Science.gov

Sample records for hybrid polar compounds

  1. Hybrid polarization control

    NASA Astrophysics Data System (ADS)

    Gray, George R.; Ibragimov, Edem; Sluz, Joseph; Sova, Raymond

    2005-05-01

    We demonstrate a novel method of polarization control that combines rotatable waveplates (angle control) and variable retarders (retardance control). Such a "hybrid" polarization controller performs far better than conventional controllers, allowing nearly perfect arbitrary-to-arbitrary polarization transformations. We show theoretically that the two control parameters augment one another because they tend to result in orthogonal movements on the Poincaré sphere.

  2. Hybrid Compounding in New Zealand English

    ERIC Educational Resources Information Center

    Degani, Marta; Onysko, Alexander

    2010-01-01

    This study investigates hybrid compound formation of Maori and English terms in present day New Zealand English (NZE). On the background of Maori and English language contact, the phenomenon of hybrid compounding emerges as a process that, on the one hand, symbolizes the vitality of the Maori element in NZE and, on the other hand, marks the…

  3. Hybrid compounds: from simple combinations to nanomachines.

    PubMed

    Müller-Schiffmann, Andreas; Sticht, Heinrich; Korth, Carsten

    2012-02-01

    The combination of two different and independently acting compounds into one covalently linked hybrid compound can convey synergy from the effects of both independently acting moieties to the new composite compound, leading to a pharmacological potency greater than the sum of each individual moiety's potencies. Here, we review a variety of such hybrid compounds, which can consist of various functional parts, molecular recognition or subcellular targeting moieties, or combinations thereof, acting either simultaneously or sequentially. Such moieties within a hybrid compound can consist of a variety of substance classes, including small organic molecules, polypeptides or nucleic acids identified either via rational molecular design or selection from libraries. Precedent for hybrid compounds comes from naturally occurring proteins and small molecules, such as botulinum toxin and bleomycin, which are secreted by micro-organisms. We review the high degree of suitability of hybrid compounds for the treatment of multifactorial diseases by simultaneously hitting several targets along an identified disease pathway. Examples are hybrid compounds against Alzheimer's disease, against the cancer-relevant phosphoinisitide-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) and epidermal growth factor signaling cascade, or in antimalarial therapy via simultaneous hitting of different mechanisms of hemozoin formation. Molecular recognition by peptides or aptamers (recognition-specific RNA or peptide sequences) can be combined with the transport of small molecule β-sheet breakers or toxins, or targeting to ubiquitin-dependent proteolysis. The vision of molecular nanomachines is currently realized in sequentially acting modular nanotransporters, consisting of four modules including a target, a membrane and nuclear translocation sequence, as well as a drug attachment domain. Through the rational combination of existing drugs and the synergy of their effects, a rapid

  4. Quinoline-based antimalarial hybrid compounds.

    PubMed

    Vandekerckhove, Stéphanie; D'hooghe, Matthias

    2015-08-15

    Quinoline-containing compounds, such as quinine and chloroquine, have a long-standing history as potent antimalarial agents. However, the increasing resistance of the Plasmodium parasite against these drugs and the lack of licensed malaria vaccines have forced chemists to develop synthetic strategies toward novel biologically active molecules. A strategy that has attracted considerable attention in current medicinal chemistry is based on the conjugation of two biologically active molecules into one hybrid compound. Since quinolines are considered to be privileged antimalarial building blocks, the synthesis of quinoline-containing antimalarial hybrids has been elaborated extensively in recent years. This review provides a literature overview of antimalarial hybrid molecules containing a quinoline core, covering publications between 2009 and 2014. PMID:25593097

  5. Conceptual design of a hybrid-type elliptically polarizing undulator

    NASA Astrophysics Data System (ADS)

    Sasaki, Shigemi

    2002-03-01

    A hybrid-type planar undulator was designed to generate circularly polarized radiation. It is an APPLE-type design consisting of four rows of hybrid structures that can be shifted with respect to each other. The magnetic field on axis can thus be adjusted so it can have linear or circular polarization including intermediate (elliptical polarization) positions. A short-period device of this kind can provide 100% circularly polarized radiation in a hard x-ray region when it is installed in a high-energy storage ring, such as the Advanced Photon Source.

  6. Creatinyl amino acids: new hybrid compounds with neuroprotective activity.

    PubMed

    Burov, Sergey; Leko, Maria; Dorosh, Marina; Dobrodumov, Anatoliy; Veselkina, Olga

    2011-09-01

    Prolonged oral creatine administration resulted in remarkable neuroprotection in experimental models of brain stroke. However, because of its polar nature creatine has poor ability to penetrate the blood-brain barrier (BBB) without specific creatine transporter (CRT). Thus, synthesis of hydrophobic derivatives capable of crossing the BBB by alternative pathway is of great importance for the treatment of acute and chronic neurological diseases including stroke, traumatic brain injury and hereditary CRT deficiency. Here we describe synthesis of new hybrid compounds-creatinyl amino acids, their neuroprotective activity in vivo and stability to degradation in different media. The title compounds were synthesized by guanidinylation of corresponding sarcosyl peptides or direct creatine attachment using isobutyl chloroformate method. Addition of lipophilic counterion (p-toluenesulfonate) ensures efficient creatine dissolution in DMF with simultaneous protection of guanidino group towards intramolecular cyclization. It excludes the application of expensive guanidinylating reagents, permits to simplify synthetic procedure and adapt it to large-scale production. The biological activity of creatinyl amino acids was tested in vivo on ischemic stroke and NaNO(2) -induced hypoxia models. One of the most effective compounds-creatinyl-glycine ethyl ester increases life span of experimental animals more than two times in hypoxia model and has neuroprotective action in brain stroke model when applied both before and after ischemia. These data evidenced that creatinyl amino acids can represent promising candidates for the development of new drugs useful in stroke treatment. PMID:21644247

  7. Temporal stability of polar organic compounds in stainless steel canisters

    SciTech Connect

    Pate, B.; Jayanty, R.K.M.; Peterson, M.R. ); Evans, G.F. )

    1992-04-01

    Because of considerable interest at US EPA for the collection of polar organic compounds in stainless steel canisters, particularly for the Toxic Air Monitoring Site (TAMS) study, the stability of 10 selected polar organics in canisters was investigated and the results are described in this paper. The polar organic compounds selected for this stability study were: methanol, acetone, isoprene, acrylonitrile, vinyl acetate, methyl ethyl ketone, t-butyl methyl ether, ethyl acetate, n-butanol, and ethyl acrylate. Two nonpolar compounds, methyl chloroform and toluene, shown to be stable in previous work were included in the stability study as controls. The compounds were loaded in unpolished and Summa-polished canisters at parts-per-billion (ppb) levels under dry and humid conditions. The canister samples were analyzed on Days 0, 1, 3, 4, 14, and 31 after loading. The experimental procedures and stability results are summarized briefly.

  8. Hybrid-Polarity SAR Architecture for Sea Oil Slick Monitoring

    NASA Astrophysics Data System (ADS)

    Buono, A.; Nunziata, F.; Li, X.; Wei, Y.; Ding, X.

    2014-11-01

    In this study, Compact Polarimetry (CP) architectures are exploited for oil slicks at sea observation purposes. In particular, Hybrid-Polarity (HP) architecture, which consists of transmitting a circularly-polarized field while receiving coherently according to a linear h-v base, is investigated. Basic concepts of wave polarimetry are used to define HP features for oil slicks monitoring. Experiments are undertaken on HP measurements emulated from actual C-band Full-Polarimetric (FP) Synthetic Aperture Radar (SAR) data. HP features performance in terms of oil slick detection and discrimination (from look-alikes and between different kinds of oil) is shown to be very close to the FP one.

  9. Volatile and polar compounds in Rosadamascena Mill 1803 cell suspension.

    PubMed

    Pavlov, Atanas; Popov, Simeon; Kovacheva, Elena; Georgiev, Milen; Ilieva, Mladenka

    2005-07-21

    Studies were conducted on low molecular metabolites (volatiles and polar compounds) produced by Rosa damascena Mill 1803 cell suspension culture, cultivated under different regimes: as a free suspension (in flasks and in bioreactor) and in a two-phase system (in the presence of Amberlite XAD-4 as a second phase). It was established that the main groups of volatiles were hydrocarbons and free acids and their esters and only traces of terpenoids were found. The main components of polar fraction were free acids, especially amino acids and oxidized acids. Depending on the culture conditions, significant differences were established in the amounts of all compounds under study in biomasses, culture media and adsorbed on the second phase (Amberlite XAD-4). PMID:15899533

  10. Hybrid em wave - polar semiconductor interaction: A polaronic study

    SciTech Connect

    Paliwal, Ayushi Dubey, Swati; Ghosh, S.

    2015-07-31

    Present paper considers incidence of a most realistic hybrid pump wave on a weakly polar semiconductor having a very small coupling constant. Possibility of optical parametric interaction has been explored in the presence of an external transverse magnetic field. The effect of doping concentrations and transverse magnetostatic field on threshold characteristics of optical parametric interaction in polar semiconductor plasma has been studied, using hydrodynamic model of semiconductors, in the far infrared regime. Numerical estimations have been carried out by using data of weakly polar III-V GaAs semiconductor and influence of control parameters on electron-LO phonon interaction has been analyzed. A particular range of physical parameters is found to be suitable for minimum threshold. The choice of nonlinear medium and favorable range of operating parameters are crucial aspects in design and fabrication of parametric amplifiers and oscillators. The hybrid mode of the pump is found to be favorable for the onset of the said process and realization of a low cost amplifier.

  11. Hybrid polarizing solids for pure hyperpolarized liquids through dissolution dynamic nuclear polarization

    PubMed Central

    Gajan, David; Bornet, Aurélien; Vuichoud, Basile; Milani, Jonas; Melzi, Roberto; van Kalkeren, Henri A.; Veyre, Laurent; Thieuleux, Chloé; Conley, Matthew P.; Grüning, Wolfram R.; Schwarzwälder, Martin; Lesage, Anne; Copéret, Christophe; Bodenhausen, Geoffrey; Emsley, Lyndon; Jannin, Sami

    2014-01-01

    Hyperpolarization of substrates for magnetic resonance spectroscopy (MRS) and imaging (MRI) by dissolution dynamic nuclear polarization (D-DNP) usually involves saturating the ESR transitions of polarizing agents (PAs; e.g., persistent radicals embedded in frozen glassy matrices). This approach has shown enormous potential to achieve greatly enhanced nuclear spin polarization, but the presence of PAs and/or glassing agents in the sample after dissolution can raise concerns for in vivo MRI applications, such as perturbing molecular interactions, and may induce the erosion of hyperpolarization in spectroscopy and MRI. We show that D-DNP can be performed efficiently with hybrid polarizing solids (HYPSOs) with 2,2,6,6-tetramethyl-piperidine-1-oxyl radicals incorporated in a mesostructured silica material and homogeneously distributed along its pore channels. The powder is wetted with a solution containing molecules of interest (for example, metabolites for MRS or MRI) to fill the pore channels (incipient wetness impregnation), and DNP is performed at low temperatures in a very efficient manner. This approach allows high polarization without the need for glass-forming agents and is applicable to a broad range of substrates, including peptides and metabolites. During dissolution, HYPSO is physically retained by simple filtration in the cryostat of the DNP polarizer, and a pure hyperpolarized solution is collected within a few seconds. The resulting solution contains the pure substrate, is free from any paramagnetic or other pollutants, and is ready for in vivo infusion. PMID:25267650

  12. Characterization of polarized THP-1 macrophages and polarizing ability of LPS and food compounds.

    PubMed

    Chanput, Wasaporn; Mes, Jurriaan J; Savelkoul, Huub F J; Wichers, Harry J

    2013-02-01

    Little is known about the polarizing potential of currently used human macrophage cell lines, while a better understanding phenomena can support the prediction of effects in vivo based on in vitro analysis. To test the polarization capability of PMA differentiated-THP-1 macrophages (M0), cells were stimulated with 20 ng ml(-1) IFNγ + 1 μg ml(-1) LPS and 20 ng ml(-1) IL-4, which are known to influence macrophage polarization in vivo and ex vivo into the M1 and M2 state, respectively. Apart from several well-known M1 and M2 markers, also new possible markers for M1 and M2 polarization were analysed in this study. The expression of M1 marker genes was up-regulated in IFNγ + LPS stimulated-M0 THP-1 macrophages. The IL-4 stimulated-M0 THP-1 macrophages expressed M2 cell membrane receptor genes. However, M2 chemokine and their receptor genes were only slightly up-regulated which might be due to the complexity of the secondary cell-cell interaction of the chemokine system. Lipopolysaccharides from E. coli (LPS) and food compounds [lentinan, vitamin D3 (vD3) and the combination of lentinan + vitamin D3 (Len + vD3)] were investigated for their polarizing ability on M0 THP-1 macrophages towards either the M1 or M2 state. LPS (700 ng ml(-1)) was able to skew M0 THP-1 macrophages towards the M1 direction since all analysed M1 marker genes were strongly expressed. Lentinan, vD3 and Len + vD3 did not induce expression of either M1 or M2 markers, indicating no polarizing ability of these compounds. Based on the expression of M1 and M2 marker genes we concluded that THP-1 macrophages could be successfully polarized into either the M1 or M2 state. Therefore, they can be used as a new macrophage polarizing model to estimate the polarizing/switching ability of test food compounds. PMID:23135314

  13. Purification of polar compounds from Radix isatidis using conventional C18 column coupled with polar-copolymerized C18 column.

    PubMed

    Zeng, Jing; Guo, Zhimou; Xiao, Yuansheng; Wang, Chaoran; Zhang, Xiuli; Liang, Xinmiao

    2010-11-01

    Regarding hydrophilic interaction chromatography and normal phase liquid chromatography, RPLC is another choice used to separate polar compounds with the improvement of polar-modified C18 stationary phase. In this study, a method using conventional C18 column coupled with polar-copolymerized C18 column was successfully developed for the separation and purification of polar compounds from Radix isatidis, which is one of the most commonly used traditional Chinese medicines (TCMs). An XTerra MS C18 column was used to fractionate the extract of R. isatidis and a homemade polar-copolymerized C18 column was utilized for the final purification due to its good separation selectivity and high resolution for polar compounds. The established purification system demonstrated good orthogonality for the polar compounds. As a result, ten compounds were purified and three of them were identified as 3-methyl-5-vinyloxazolidin-2-one (compound A), 5-hydroxymethyl-2-furaldehyde (compound B) and 3-methylfuran-2-carboxylic acid (compound G) based on the MS, IR and extensive NMR data, respectively. It was demonstrated to be a feasible and powerful technique for the purification of polar compounds under RPLC mode and more chemical information of TCMs will be obtained to interpret the efficiency of TCMs. PMID:20886519

  14. Polarization conversion by hybrid modes: Theory and applications

    NASA Astrophysics Data System (ADS)

    Mertens, K.; Sennewald, M.; Schmitt, H. J.

    1996-11-01

    In strip-loaded slab waveguides, mode coupling between the transverse magnetic (TM11) and the transverse electric (TE21) modes can occur even if isotropic materials such as InP or GaAs are used. This coupling leads to new eigenmodes with a strong hybrid character, that is, the strength of the transverse side components is in the range of the main components. We show that the effect can be explained by a perturbation analysis investigating a raised strip waveguide, which is thought as a superposition of a buried strip waveguide and a dielectric perturbation in the region of the substrate. The described mode-coupling effect should be taken into account when designing integrated optic components, where strip and strip-loaded slab waveguides are commonly used. On the other hand, the hybrid modes can be used to develop new TE/TM converters. We present a new device based on InP which converts an input TE polarization into a mixture of TE and TM polarization, making it an interesting candidate for coherent receiver chips.

  15. Introgressive hybridization: brown bears as vectors for polar bear alleles.

    PubMed

    Hailer, Frank

    2015-03-01

    The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. PMID:25775930

  16. Hybridization effects in selected actinides and their compounds

    NASA Astrophysics Data System (ADS)

    El-Khatib, Sami T.

    Many actinide systems exhibit 'unusual' phenomena that differ from the normal text-book behavior. This occurs because the 5f electrons of the actinides and their compounds experience a delicate balance between local-moment and itinerant magnetism. It is well established that strong-electron correlations affect the different properties in such systems. Even though the actinides and their compounds have been extensively studied in recent decades, both experimentally and theoretically, to date, no complete understanding of the full range of their properties has been achieved. My thesis focuses mainly on understanding the role of 5f electrons and their interactions with the electron states of the surrounding ligands. Particularly, the effect of the 5f-ligand hybridization in the development of bulk properties is investigated. The experimental studies utilized macroscopic techniques, such as magnetization, electrical-resistivity, specific-heat and resonant-ultrasound-spectroscopy measurements, as well as microscopic techniques, such as neutron-diffraction and muon-spin-resonance studies. The results are used to disentangle the importance of direct 5f--5f overlap and 5 f-ligand hybridization. The following features have been investigated in this thesis: (a) the dual nature of hybridization effects (magnetic moment reduction vs. exchange mediation) was studied for two isostructural uranium compounds U2Pd2Sn and U2Ni2 In; (b) the formation of complex magnetic structures and its connection to the hybridization effects was studied for UCuSn, UPdSn and UPdGe; (c) the tuning of the hybridization to critical values through substitutions was attempted for two single crystals of UCoAl1-xSn x and UNi1-xRh xAl alloys; (d) the effects of compositional deficiencies was studied for the copper-deficient compound in UCu1.5Sn 2; and finally, (e) the influence of strong electron correlations on the elastic properties was studied in the case of alpha-Pu.

  17. On the R 5d band polarization in rare-earth-transition metal compounds.

    PubMed

    Burzo, E; Chioncel, L; Tetean, R; Isnard, O

    2011-01-19

    Magnetic measurements and band structure calculations were performed on RT(2) and RT(5) compounds, where R is a heavy rare-earth and T = Fe, Co, Ni, Al, as well as on pseudobinary compounds GdCo(2 - x)A(x) (A = Ni, Cu, Si), YFe(2 - x)V(x) and YCo(4 - x)Ni(x)B. The calculated moments per formula unit described well the experimentally determined magnetizations. By considering the 4f-5d-3d exchange interactions, we evaluate the contributions of local 4f-5d and short range 5d-3d interactions to R 5d and Y 4d band polarizations. The 4f-5d induced polarizations are proportional to the De Gennes factor and are the same for a given R and a similar type structure. The R 5d and Y 4d band polarizations induced by R 5d-T3d or Y 4d-T3d hybridizations are proportional to the number of neighbouring T atoms, to a given R, and their magnetic moments. Previous results on the matter are also discussed. PMID:21406851

  18. Towards Hybrid Quantum Information Processing with Polar Molecules

    NASA Astrophysics Data System (ADS)

    Rabl, Peter

    2008-05-01

    With the ongoing miniaturization of on-chip traps for atoms and ions it is timely to think about coherent interfaces between AMO and solid state systems with potential applications for new hybrid implementations for quantum computers. In this talk I will discuss a potential scenario, where ensembles of polar molecules serve as long-lived quantum memories for superconducting qubits and quantum information is transmitted via a high-Q microwave cavity. Polar molecules combine the exceptional features of a large electric dipole moment and long-lived rotational states with level splittings in the GHz regime. When trapped close to the surface of a chip this combination allows strong interactions with coherent solid state devices, e.g., superconducting microwave cavities or Josephson qubits. I will first introduce the system consisting of a single polar molecule coupled to a stripline cavity which realizes a cavity QED system in the microwave regime and discuss applications for quantum information processing, state detection and new cavity-assisted cooling schemes for polar molecules. I will then switch to molecular ensemble qubits where quantum information is encoded in collective spin or rotational excitations of an ensemble of N molecules. Ensemble qubits benefit from a collectively enhanced coupling ˜√N which allows quantum state transfer between the molecules and, e.g., a charge qubit on a timescale that is compatible with typical coherence times in a solid state environment. With the goal to protect ensemble qubits from collisions, I will finally discuss a scenario, where molecules are prepared in a crystalline phase under 1D trapping conditions and dipole moments aligned by an external field.

  19. Synthesis of New 'Hybrid' Compounds Based on Benzofuroxans and Aminoalkylnaphthalimides.

    PubMed

    Chugunova, Elena; Mukhamatdinova, Rezeda; Sazykina, Marina; Dobrynin, Alexey; Sazykin, Ivan; Karpenko, Alexander; Mirina, Elena; Zhuravleva, Maria; Gavrilov, Nikolai; Karchava, Shorena; Burilov, Alexander

    2016-04-01

    Pathogenic bacteria and fungi eventually develop resistance to existing drugs, and therefore, we need constant development of new drugs. The research is aimed at addressing fundamental scientific problems-the search for new biologically active compounds among several benzofuroxan-containing 'hybrid' products. N-substituted naphthalimides were chosen as a second pharmacophore. Benzofuroxanes biological effects were studied by means of bacterial lux-biosensors. Compounds IIIa, IVa, IIIc, and IVc displayed more expressed bacteriotoxic action in comparison with the initial substances Ia-c and represent a certain interest for using as antibacterial substances. PMID:26575416

  20. Characterisation of polar organic compounds in fog water

    NASA Astrophysics Data System (ADS)

    Kiss, Gyula; Varga, Bálint; Gelencsér, András; Krivácsy, Zoltán; Molnár, Ágnes; Alsberg, Tomas; Persson, Linn; Hansson, Hans-Christen; Cristina Facchini, Maria

    In this paper the results of a systematic liquid chromatographic investigation are described to characterise water-soluble organic compounds in fog. A diode array detector is used to record the UV spectrum of the components during separation and a mass spectrometer is applied to obtain information on the ion masses of the constituents. The combination of UV and mass spectra reveal that the organic carbon content of fog water is distributed among a great number of acidic compounds which have polar functional groups and polyconjugated systems absorbing up to 500 nm. Due to the complexity of the organic fraction in fog water an unresolved hump of ions was recorded by the mass spectrometer from m/ z=100-600 the most intense peaks being detected around m/ z=200-250. Tannin and fulvic acid were also examined under the same conditions. In terms of complexity and ion distribution the mass spectrum of the organic fraction was similar to that of a fulvic acid reference material rather than to that of tannin.

  1. Volatile organic compounds adsorption onto neat and hybrid bacterial cellulose

    NASA Astrophysics Data System (ADS)

    Ion, Violeta Alexandra; Pârvulescu, Oana Cristina; Dobre, Tănase

    2015-04-01

    Adsorption dynamics of VOCs (volatile organic compounds) vapour from air streams onto fixed bed adsorbent were measured and simulated under various operation conditions. Isopropanol (IPA) and n-hexane (HEX) were selected as representatives of polar and nonpolar VOCs, whereas bacterial cellulose (BC) and BC incorporated with magnetite nanoparticles (M/BC), were tested as adsorbents. An experimental study emphasizing the influence of air superficial velocity (0.7 cm/s and 1.7 cm/s), operation temperature (30 °C and 40 °C), adsorbate and adsorbent type, on fixed bed saturation curves was conducted. Optimal adsorption performances evaluated in terms of saturation adsorption capacity were obtained for the adsorption of polar compound (IPA) onto M/BC composite (0.805 g/g) and of nonpolar compound (HEX) onto neat BC (0.795 g/g), respectively, at high values of air velocity and operation temperature. A mathematical model including mass balance of VOC species, whose parameters were fitted based on experimental data, was developed in order to predict the fixed bed saturation curves. A 23 statistical model indicating a significant increase in adsorption performances with process temperature was validated under the experimental conditions.

  2. Solid fat content as a substitute for total polar compound analysis in edible oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The solid fat contents (SFC) of heated edible oil samples were measured and found to correlate positively with total polar compounds (TPC) and inversely with triglyceride concentration. Traditional methods for determination of total polar compounds require a laboratory setting and are time intensiv...

  3. Polarization switch of four-wave mixing in large mode area hybrid photonic crystal fibers.

    PubMed

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2015-02-15

    Degenerate spontaneous four-wave mixing is considered in a large mode area hybrid photonic crystal fiber. Numerical and experimental results show birefringence assisted four-wave mixing for a certain polarization state of the pump field. The parametric gain can be turned on and off by switching the polarization state of the pump field between the two principal axis of the hybrid photonic crystal fiber. PMID:25680131

  4. Plasmon-optical phonon hybridization in polar semiconductor nano-wires

    NASA Astrophysics Data System (ADS)

    Moradi, Afshin

    2013-12-01

    The hybridization of the plasmon oscillations with the optical phonon waves in cylindrical polar semiconductor nano-wires is investigated. A simple model based on the hydrodynamic theory in conjunction with the Poisson's equation is proposed. An explicit form of the dispersion relation for hybridized surface plasmon-optical phonon modes of the system is derived.

  5. Hybrid polarization-angle multiplexing for volume holography in gold nanoparticle-doped photopolymer.

    PubMed

    Li, Chengmingyue; Cao, Liangcai; Wang, Zheng; Jin, Guofan

    2014-12-15

    We report on volume holographic hybrid polarization-angle multiplexing in a gold nanoparticle-doped photopolymer. When doping the gold nanoparticles, the linear photoinduced birefringence of the phenanthrenequinone-doped poly (methyl methacrylate) (PQ/PMMA) photopolymer could be increased by nearly 38%. The data pages could be recorded with the orthogonal circular polarization multiplexing, and the reconstructed images have a symbol-error rate of 3.81% and 4.46% for left circular polarization and right circular polarization state, respectively. Two biological image sets multiplexed both with the angle interval of 0.1° and with orthogonal circular polarization are reconstructed separately and simultaneously. PMID:25503023

  6. Hybrid curcumin compounds: a new strategy for cancer treatment.

    PubMed

    Teiten, Marie-Hélène; Dicato, Mario; Diederich, Marc

    2014-01-01

    Cancer is a multifactorial disease that requires treatments able to target multiple intracellular components and signaling pathways. The natural compound, curcumin, was already described as a promising anticancer agent due to its multipotent properties and huge amount of molecular targets in vitro. Its translation to the clinic is, however, limited by its reduced solubility and bioavailability in patients. In order to overcome these pharmacokinetic deficits of curcumin, several strategies, such as the design of synthetic analogs, the combination with specific adjuvants or nano-formulations, have been developed. By taking into account the risk-benefit profile of drug combinations, as well as the knowledge about curcumin's structure-activity relationship, a new concept for the combination of curcumin with scaffolds from different natural products or components has emerged. The concept of a hybrid curcumin molecule is based on the incorporation or combination of curcumin with specific antibodies, adjuvants or other natural products already used or not in conventional chemotherapy, in one single molecule. The high diversity of such conjugations enhances the selectivity and inherent biological activities and properties, as well as the efficacy of the parental compound, with particular emphasis on improving the efficacy of curcumin for future clinical treatments. PMID:25514225

  7. Spin Polarized Conductance in Hybrid Graphene Nanoribbons Using 5-7 Defects

    SciTech Connect

    Sumpter, Bobby G; Meunier, Vincent; Cruz Silva, Eduardo; Terrones Maldonado, Humberto; Terrones Maldonado, Mauricio; Lopez, Florentino; Botello Mendez, Andres R

    2009-01-01

    We present a class of intramolecular graphene heterojunctions and use first-principles density functional calculations to describe their electronic, magnetic, and transport properties. The hybrid graphene and hybrid graphene nanoribbons have both armchair and zigzag features that are separated by an interface made up of pentagonal and heptagonal carbon rings. Contrary to conventional graphene sheets, the computed electronic density of states indicates that all hybrid graphene and nanoribbon systems are metallic. Hybrid nanoribbons are found to exhibit a remarkable width-dependent magnetic behavior and behave as spin polarized conductors.

  8. Broadband cross polarization converter using plasmon hybridizations in a ring/disk cavity.

    PubMed

    Shi, Hongyu; Li, Jianxing; Zhang, Anxue; Wang, Jiafu; Xu, Zhuo

    2014-08-25

    In this paper, we report on the design, fabrication and subsequent investigation of a broad band cross polarization converter based on a C2-symmetric ring/disk cavity. Different plasmon hybridization modes are excited in the ring/disk cavity and enable the polarization manipulations. The designed cross polarization converter can convert the x or y polarized incident wave to its cross polarized wave in the frequency range from 9.65 to 14.16 GHz with a bandwidth of ~38% of the central wavelength and an efficiency higher than 80%. At 9.25 GHz and 14.35 GHz, the x (y) polarized incident wave is converted to a left (right) handed and right (left) handed circularly polarized wave, respectively. PMID:25321298

  9. Influences of polar auxin transport on polarity of adventitious bud formation in hybrid populas

    SciTech Connect

    Kim, Myung Won ); Hackett, W. )

    1989-04-01

    The role of auxin and cytokinin distribution of polar regeneration of adventitious bud has been investigated. Explants from leaf midvein were labelled with {sup 14}C-NAA and {sup 14}C-BA and the radioactivity in proximal, mid, and distal portions was counted after 24h and 48h. Explants showing polar regeneration of buds on the proximal end showed a clear polar distribution of {sup 14}CNAA. Auxin transport inhibitors (NPA, TIBA) eliminated polar distribution of auxin and reduced polarity of bud formation and the total number of buds formed, but did not reduce callus formation. Increased concentration of Ca(NO{sub 3}){sub 2} decreased polarity of bud formation and increased the number of buds formed but did not affect the distribution of auxin of cytokinin. Some factor in addition to polar distribution of auxin or cytokinin-auxin ratio appears to influence the polarity of adventitious bud formation.

  10. Polarization Domain Switching of Improper Hybrid Ferroelectric (Ca,Sr)3Ti2O7 Crystals

    NASA Astrophysics Data System (ADS)

    Lim, Seong Joon; Gao, Bin; Kim, Jaewook; Huang, Fei-Ting; Cheong, Sang-Wook; RCEM Team

    The observation of switchable polarization loops at room temperature in (Ca,Sr)3Ti2O7, induced by improper hybrid ferroelectricity, has drawn much attention. Since the ferroelectric polarization directly couples with structural distortions (oxygen octahedral tilting and rotation) in hybrid improper ferroelectrics, the energy barrier for polarization switching is predicted to be large, and the observation of ferroelectric polarization loops was a surprise. Furthermore, the observed complexity of the domain wall configuration in (Ca,Sr)3Ti2O7 may complicate the domain wall motion or the domain nucleation for polarization switching. Thus, it is imperative to understand the mechanism and dynamics of polarization domain switching. Particularly, it has to be clarified if polarization switching occurs through 90° or 180° switching. Comparing piezoresponse force microscope and polarized optical microscope images before and after applying electric fields consecutively, we explored the mechanism and dynamics of polarization domain switching. This work is funded by the Gordon and Betty Moore Foundation's EPiQS Initiative through Grant GBMF4413 to the Rutgers Center for Emergent Materials.

  11. Spin-Polarized Hybridization at the interface between different 8-hydroxyquinolates and the Cr(001) surface

    NASA Astrophysics Data System (ADS)

    Wang, Jingying; Deloach, Andrew; Dougherty, Daniel B.; Dougherty Lab Team

    Organic materials attract a lot of attention due to their promising applications in spintronic devices. It is realized that spin-polarized metal/organic interfacial hybridization plays an important role to improve efficiency of organic spintronic devices. Hybridized interfacial states help to increase spin injection at the interface. Here we report spin-resolved STM measurements of single tris(8-hydroxyquinolinato) aluminum molecules adsorbed on the antiferromagnetic Cr(001). Our observations show a spin-polarized interface state between Alq3 and Cr(001). Tris(8-hydroxyquinolinato) chromium has also been studied and compared with Alq3, which exhibits different spin-polarized hybridization with the Cr(001) surface state than Alq3. We attribute the differences to different character of molecular orbitals in the two different quinolates.

  12. IDENTIFICATION AND QUANTIFICATION OF AEROSOL POLAR OXYGENATED COMPOUNDS BEARING CARBOXYLIC OR HYDROXYL GROUPS. 2. ORGANIC TRACER COMPOUNDS FROM MONOTERPENES

    EPA Science Inventory

    A comparison was made of polar organic compounds found in the field with those produced in secondary organic aerosol from laboratory irradiations of natural hydrocarbons and oxides of nitrogen. The field samples comprised atmospheric particulate matter (PM2.5) collect...

  13. DETERMINATION OF POLAR VOLATILE ORGANIC COMPOUNDS IN WATER BY MEMBRANE PERMEATE AND TRAP GC-MS

    EPA Science Inventory

    A novel approach is presented combining semipermeable membranes with the accepted purge and trap gas chromatography-mass spectrometry (GC-MS) technology to produce a method of selectively extracting polar, volatile organic compounds from water, particularly those compounds not am...

  14. Performance of commercial non-methane hydrocarbon analyzers in monitoring polar volatile organic compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantifying non-methane hydrocarbons (NMHC) from animal feeding operations (AFOs) is challenging due to the broad spectrum of compounds and the polar nature of the most abundant compounds. The purpose of this study was to determine the performance of commercial NMHC analyzers for measuring volatile ...

  15. The role of spontaneous polarization in the negative thermal expansion of tetragonal PbTiO3-based compounds.

    PubMed

    Chen, Jun; Nittala, Krishna; Forrester, Jennifer S; Jones, Jacob L; Deng, Jinxia; Yu, Ranbo; Xing, Xianran

    2011-07-27

    PbTiO(3)-based compounds are well-known ferroelectrics that exhibit a negative thermal expansion more or less in the tetragonal phase. The mechanism of negative thermal expansion has been studied by high-temperature neutron powder diffraction performed on two representative compounds, 0.7PbTiO(3)-0.3BiFeO(3) and 0.7PbTiO(3)-0.3Bi(Zn(1/2)Ti(1/2))O(3), whose negative thermal expansion is contrarily enhanced and weakened, respectively. With increasing temperature up to the Curie temperature, the spontaneous polarization displacement of Pb/Bi (δz(Pb/Bi)) is weakened in 0.7PbTiO(3)-0.3BiFeO(3) but well-maintained in 0.7PbTiO(3)-0.3Bi(Zn(1/2)Ti(1/2))O(3). There is an apparent correlation between tetragonality (c/a) and spontaneous polarization. Direct experimental evidence indicates that the spontaneous polarization originating from Pb/Bi-O hybridization is strongly associated with the negative thermal expansion. This mechanism can be used as a guide for the future design of negative thermal expansion of phase-transforming oxides. PMID:21696173

  16. Polarization-dependent fluorescence from an anisotropic gold/polymer hybrid nano-emitter

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Deeb, C.; Vincent, R.; Lerond, T.; Adam, P.-M.; Plain, J.; Wiederrecht, G. P.; Charra, F.; Fiorini, C.; Colas des Francs, G.; Soppera, O.; Bachelot, R.

    2014-01-01

    Based on nanoscale photopolymerization triggered by the dipolar surface plasmon mode, we developed a light-emitting gold nanoparticle/Eosin Y-doped polymer hybrid nanostructure. Due to the anisotropic spatial distribution of the dipolar surface plasmon mode during photopolymerization, this nano-emitter is anisotropic in both geometry and emission. The trapped dye molecules in the hybrid nanostructure display fluorescence intensity that is dependent upon the polarization of the incident excitation light. This nano-emitter further allows the photo-selection of fluorescence configuration (i.e., molecule concentration and refractive index of active medium) by controlling the incident polarization.

  17. Deviations from sorption linearity on soils of polar and nonpolar organic compounds at low relative concentrations

    USGS Publications Warehouse

    Chiou, C.T.; Kile, D.E.

    1998-01-01

    A series of single-solute and binary-solute sorption data have been obtained on representative samples of polar compounds (substituted ureas and phenolic compounds) and of nonpolar compounds (e.g., EDB and TCE) on a peat soil and a mineral (Woodburn) soil; the data extend to low relative solute concentrations (C(e)/S(w)). At relatively low C(e)/S(w), both the nonpolar and the polar solutes exhibit nonlinear sorption. The sorption nonlinearity approaches apparent saturation at about C(e)/S(w) = 0.010-0.015 for the nonpolar solutes and at about C(e)/S(w) = 0.10-0.13 for the polar solutes; above these C(e)/S(w) regions, the isotherms are practically linear. The nonlinear sorption capacities are greater for polar solutes than for nonpolar solutes and the peat soil shows a greater effect than the Woodburn soil. The small nonlinear sorption capacity for a nonpolar solute is suppressed indiscriminately by either a nonpolar or a polar cosolute at relatively low C(e)/S(w) of the cosolute. By contrast, the abilities of different cosolutes to suppress the nonlinear capacity of a nominal polar solute differ drastically. For polar solutes, a nonpolar cosolute exhibits a limited suppression even at high cosolute C(e)/S(w); effective suppression occurs when the cosolute is relatively polar and at various C(e)/S(w). These differences suggest that more than a single mechanism is required to account for the nonlinear sorption of both nonpolar and polar compounds at low C(e)/S(w). Mechanistic processes consistent with these observations and with soil surface areas are discussed along with other suggested models. Some important consequences of the nonlinear competitive sorption to the behavior of contaminants in natural systems are discussed.A number of conceptual models was postulated to account for the nonlinear solute sorption on soils of significant soil organic matter. A series of single-solute and binary-route sorption data was obtained representing samples of polar compounds of

  18. Hybrid plasmonic waveguide-based ultra-low insertion loss transverse electric-pass polarizer.

    PubMed

    Sun, X; Mojahedi, M; Aitchison, J S

    2016-09-01

    We have designed and experimentally demonstrated an integrated transverse electric (TE)-pass polarizer on silicon-on-insulator platform. The polarizer consists of an asymmetric coupling section where only the transverse magnetic (TM) mode is coupled to the cross-hybrid plasmonic waveguide and attenuated. The TE mode does not couple and passes through the polarizer. The polarizer was fabricated on the silicon-on-insulator platform. The device is 30 μm long, has a high extinction ratio of more than 28 dB over 150 nm bandwidth, and has a good fabrication tolerance. Most important, the proposed polarizer has an ultra-low insertion loss of less than 0.04 dB for the TE mode. PMID:27607962

  19. Nanoscale switch for vortex polarization mediated by Bloch core formation in magnetic hybrid systems

    PubMed Central

    Wohlhüter, Phillip; Bryan, Matthew Thomas; Warnicke, Peter; Gliga, Sebastian; Stevenson, Stephanie Elizabeth; Heldt, Georg; Saharan, Lalita; Suszka, Anna Kinga; Moutafis, Christoforos; Chopdekar, Rajesh Vilas; Raabe, Jörg; Thomson, Thomas; Hrkac, Gino; Heyderman, Laura Jane

    2015-01-01

    Vortices are fundamental magnetic topological structures characterized by a curling magnetization around a highly stable nanometric core. The control of the polarization of this core and its gyration is key to the utilization of vortices in technological applications. So far polarization control has been achieved in single-material structures using magnetic fields, spin-polarized currents or spin waves. Here we demonstrate local control of the vortex core orientation in hybrid structures where the vortex in an in-plane Permalloy film coexists with out-of-plane maze domains in a Co/Pd multilayer. The vortex core reverses its polarization on crossing a maze domain boundary. This reversal is mediated by a pair of magnetic singularities, known as Bloch points, and leads to the transient formation of a three-dimensional magnetization structure: a Bloch core. The interaction between vortex and domain wall thus acts as a nanoscale switch for the vortex core polarization. PMID:26238042

  20. Nanoscale switch for vortex polarization mediated by Bloch core formation in magnetic hybrid systems

    NASA Astrophysics Data System (ADS)

    Wohlhüter, Phillip; Bryan, Matthew Thomas; Warnicke, Peter; Gliga, Sebastian; Stevenson, Stephanie Elizabeth; Heldt, Georg; Saharan, Lalita; Suszka, Anna Kinga; Moutafis, Christoforos; Chopdekar, Rajesh Vilas; Raabe, Jörg; Thomson, Thomas; Hrkac, Gino; Heyderman, Laura Jane

    2015-08-01

    Vortices are fundamental magnetic topological structures characterized by a curling magnetization around a highly stable nanometric core. The control of the polarization of this core and its gyration is key to the utilization of vortices in technological applications. So far polarization control has been achieved in single-material structures using magnetic fields, spin-polarized currents or spin waves. Here we demonstrate local control of the vortex core orientation in hybrid structures where the vortex in an in-plane Permalloy film coexists with out-of-plane maze domains in a Co/Pd multilayer. The vortex core reverses its polarization on crossing a maze domain boundary. This reversal is mediated by a pair of magnetic singularities, known as Bloch points, and leads to the transient formation of a three-dimensional magnetization structure: a Bloch core. The interaction between vortex and domain wall thus acts as a nanoscale switch for the vortex core polarization.

  1. Hybrid semiconducting polymer nanoparticles as polarization-sensitive fluorescent probes

    PubMed Central

    Zeigler, Maxwell B.; Sun, Wei; Rong, Yu; Chiu, Daniel T.

    2013-01-01

    Much work has been done on collapsed chains of conjugated semiconducting polymers and their applications as fluorescent probes or sensors. On surfaces spin-coated with semiconducting polymers, excitation energy transfer along the polymer backbone can be used to quickly and efficiently funnel energy to chromophores with localized energy minima. If each chromophore is immobilized within its matrix, this can result in large fluorescence anisotropy. Through nanoprecipitation of a matrix polymer blended at low mass ratios with short-chain, hydrophobic, fluorescent semiconducting polymers, we take advantage of this large fluorescence anisotropy to make polarization-sensitive nanoparticles. These nanoparticles are small at approximately 7 nm in diameter; exhibit a high quantum yield of 0.75; and are easily functionalized to bind to protein targets. By exciting the nanoparticles with polarized light on a wide-field fluorescence microscope, we are able to monitor not only protein location, but also changes in their orientation. PMID:23895535

  2. Reversible conversion of dominant polarity in ambipolar polymer/graphene oxide hybrids.

    PubMed

    Zhou, Ye; Han, Su-Ting; Sonar, Prashant; Ma, Xinlei; Chen, Jihua; Zheng, Zijian; Roy, V A L

    2015-01-01

    The possibility to selectively modulate the charge carrier transport in semiconducting materials is extremely challenging for the development of high performance and low-power consuming logic circuits. Systematical control over the polarity (electrons and holes) in transistor based on solution processed layer by layer polymer/graphene oxide hybrid system has been demonstrated. The conversion degree of the polarity is well controlled and reversible by trapping the opposite carriers. Basically, an electron device is switched to be a hole only device or vice versa. Finally, a hybrid layer ambipolar inverter is demonstrated in which almost no leakage of opposite carrier is found. This hybrid material has wide range of applications in planar p-n junctions and logic circuits for high-throughput manufacturing of printed electronic circuits. PMID:25801827

  3. Reversible Conversion of Dominant Polarity in Ambipolar Polymer/Graphene Oxide Hybrids

    PubMed Central

    Zhou, Ye; Han, Su-Ting; Sonar, Prashant; Ma, Xinlei; Chen, Jihua; Zheng, Zijian; Roy, V. A. L.

    2015-01-01

    The possibility to selectively modulate the charge carrier transport in semiconducting materials is extremely challenging for the development of high performance and low-power consuming logic circuits. Systematical control over the polarity (electrons and holes) in transistor based on solution processed layer by layer polymer/graphene oxide hybrid system has been demonstrated. The conversion degree of the polarity is well controlled and reversible by trapping the opposite carriers. Basically, an electron device is switched to be a hole only device or vice versa. Finally, a hybrid layer ambipolar inverter is demonstrated in which almost no leakage of opposite carrier is found. This hybrid material has wide range of applications in planar p-n junctions and logic circuits for high-throughput manufacturing of printed electronic circuits. PMID:25801827

  4. Reversible conversion of dominant polarity in ambipolar polymer/graphene oxide hybrids

    DOE PAGESBeta

    Zhou, Ye; Han, Su -Ting; Sonar, Prashant; Ma, Xinlei; Chen, Jihua; Zheng, Zijian; Roy, V. A. L.

    2015-03-24

    The possibility to selectively modulate the charge carrier transport in semiconducting materials is extremely challenging for the development of high performance and low-power consuming logic circuits. Systematical control over the polarity (electrons and holes) in transistor based on solution processed layer by layer polymer/graphene oxide hybrid system has been demonstrated. The conversion degree of the polarity is well controlled and reversible by trapping the opposite carriers. Basically, an electron device is switched to be a hole only device or vice versa. Finally, a hybrid layer ambipolar inverter is demonstrated in which almost no leakage of opposite carrier is found. Wemore » conclude that this hybrid material has wide range of applications in planar p-n junctions and logic circuits for high-throughput manufacturing of printed electronic circuits.« less

  5. Reversible conversion of dominant polarity in ambipolar polymer/graphene oxide hybrids

    SciTech Connect

    Zhou, Ye; Han, Su -Ting; Sonar, Prashant; Ma, Xinlei; Chen, Jihua; Zheng, Zijian; Roy, V. A. L.

    2015-03-24

    The possibility to selectively modulate the charge carrier transport in semiconducting materials is extremely challenging for the development of high performance and low-power consuming logic circuits. Systematical control over the polarity (electrons and holes) in transistor based on solution processed layer by layer polymer/graphene oxide hybrid system has been demonstrated. The conversion degree of the polarity is well controlled and reversible by trapping the opposite carriers. Basically, an electron device is switched to be a hole only device or vice versa. Finally, a hybrid layer ambipolar inverter is demonstrated in which almost no leakage of opposite carrier is found. We conclude that this hybrid material has wide range of applications in planar p-n junctions and logic circuits for high-throughput manufacturing of printed electronic circuits.

  6. Overcoming Chloroquine Resistance in Malaria: Design, Synthesis, and Structure-Activity Relationships of Novel Hybrid Compounds.

    PubMed

    Boudhar, Aicha; Ng, Xiao Wei; Loh, Chiew Yee; Chia, Wan Ni; Tan, Zhi Ming; Nosten, Francois; Dymock, Brian W; Tan, Kevin S W

    2016-05-01

    Resistance to antimalarial therapies, including artemisinin, has emerged as a significant challenge. Reversal of acquired resistance can be achieved using agents that resensitize resistant parasites to a previously efficacious therapy. Building on our initial work describing novel chemoreversal agents (CRAs) that resensitize resistant parasites to chloroquine (CQ), we herein report new hybrid single agents as an innovative strategy in the battle against resistant malaria. Synthetically linking a CRA scaffold to chloroquine produces hybrid compounds with restored potency toward a range of resistant malaria parasites. A preferred compound, compound 35, showed broad activity and good potency against seven strains resistant to chloroquine and artemisinin. Assessment of aqueous solubility, membrane permeability, and in vitro toxicity in a hepatocyte line and a cardiomyocyte line indicates that compound 35 has a good therapeutic window and favorable drug-like properties. This study provides initial support for CQ-CRA hybrid compounds as a potential treatment for resistant malaria. PMID:26953199

  7. [Effect and mechanism of immobilization of cadmium and lead compound contaminated soil using new hybrid material].

    PubMed

    Wang, Lin; Xu, Ying-Ming; Liang, Xue-Feng; Sun, Yang; Qin, Xu

    2011-02-01

    The effect of new hybrid material and its compound treatments with phosphate on immobilization of cadmium and lead in contaminated soil was investigated using a pot-culture experiment, and the immobilization mechanism of hybrid material was clarified through analysis of heavy metal fractions, sorption equilibration experiment and X-ray photoelectron spectroscopy (XPS). The single treatments of hybrid material could not significantly promote growth of Brassica chinensis, while the compound treatments of hybrid material and phosphate markedly increased dry biomass of shoots and roots, with maximal increases of 75.53% and 151.22%, respectively. Different hybrid material treatments could significantly reduce Cd and Pb concentrations in shoots, with maximal reductions of 66.79% and 48.62%, respectively, and the compound amendment treatments appeared more efficient than the single amendment treatments in reducing Cd and Pb uptake of B. chinensis. Different hybrid material treatments could significantly decrease concentrations of toxicity characteristic leaching procedure (TCLP) extractable Cd and Pb, and the compound hybrid material treatments appeared more efficient than the single treatments in reducing TCLP extractable Cd and Pb. Through the formation of bidentate ligand between metal ions and surface sulfhydryl by complexing reaction, the hybrid material could absorb and fix mobile fractions of Cd and Pb in soil, and promote transformation of acid extractable Cd and Pb into residual fraction, resulting in significant reduction of heavy metals bioavailability and mobility and then fixing remediation of contaminated soil. In summary, the compound treatment of hybrid material and phosphate is the most effective treatment for immobilization of Cd and Pb in contaminated soils, and the hybrid material inactivates Cd and Pb in soil mainly through special chemical adsorption. PMID:21528587

  8. Effects of polar and nonpolar groups on the solubility of organic compounds in soil organic matter

    USGS Publications Warehouse

    Chiou, C.T.; Kile, D.E.

    1994-01-01

    Vapor sorption capacities on a high-organic-content peat, a model for soil organic matter (SOM), were determined at room temperature for the following liquids: n-hexane, 1,4-dioxane, nitroethane, acetone, acetonitrile, 1-propanol, ethanol, and methanol. The linear organic vapor sorption is in keeping with the dominance of vapor partition in peat SOM. These data and similar results of carbon tetrachloride (CT), trichloroethylene (TCE), benzene, ethylene glycol monoethyl ether (EGME), and water on the same peat from earlier studies are used to evaluate the effect of polarity on the vapor partition in SOM. The extrapolated liquid solubility from the vapor isotherm increases sharply from 3-6 wt % for low-polarity liquids (hexane, CT, and benzene) to 62 wt % for polar methanol and correlates positively with the liquid's component solubility parameters for polar interaction (??P) and hydrogen bonding (??h). The same polarity effect may be expected to influence the relative solubilities of a variety of contaminants in SOM and, therefore, the relative deviations between the SOM-water partition coefficients (Kom) and corresponding octanol-water partition coefficients (Kow) for different classes of compounds. The large solubility disparity in SOM between polar and nonpolar solutes suggests that the accurate prediction of Kom from Kow or Sw (solute water solubility) would be limited to compounds of similar polarity.

  9. Hybrid perturbation scheme for wide beamwidth circularly polarized stacked patch microstrip antenna for satellite communication

    NASA Astrophysics Data System (ADS)

    Hossain, Mohammad Shakawat

    Circularly polarized microstrip antennas are popular for satellite communications due to their circularly polarized orientation. They are used frequently in modern day satellite communication. In order to achieve wide angular coverage in satellite communication, a wide beamwidth is required from the antenna. Traditional single layer microstrip antenna inherently demonstrates low angular beamwidth of approximately 600 to 800and thereby lacks wide angular coverage when used for satellite communication. The objective of this thesis is to design a single-fed stacked microstrip antenna using different perturbation techniques in order to achieve a wide angular beamwidth. This thesis presents a new design for a circularly polarized antenna based on the hybrid perturbation scheme. First, a method of stacked patch-ring with negative perturbation was used to generate a significantly larger beamwidth of 1060. The axial ratio (AR) bandwidth obtained is also significantly larger compared to the case when square rings are used as parasitic and driven rings with a single feed. A simulated impedance bandwidth (S11< - 10 dB) of 16%, 3 dB AR bandwidth of 8% and a peak gain of 8.65 dBic are obtained from this design. Next, a new design of stacked hybrid antenna is presented, which uses hybrid perturbations to generate circular polarization radiation. An enhanced beamwidth of 1260 was obtained. The simulation results are confirmed by the measured results.

  10. A hybrid particle-mesh method for incompressible active polar viscous gels

    NASA Astrophysics Data System (ADS)

    Ramaswamy, Rajesh; Bourantas, George; Jülicher, Frank; Sbalzarini, Ivo F.

    2015-06-01

    We present a hybrid particle-mesh method for numerically solving the hydrodynamic equations of incompressible active polar viscous gels. These equations model the dynamics of polar active agents, embedded in a viscous medium, in which stresses are induced through constant consumption of energy. The numerical method is based on Lagrangian particles and staggered Cartesian finite-difference meshes. We show that the method is second-order and first-order accurate with respect to grid and time-step sizes, respectively. Using the present method, we simulate the hydrodynamics in rectangular geometries, of a passive liquid crystal, of an active polar film and of active gels with topological defects in polarization. We show the emergence of spontaneous flow due to Fréedericksz transition, and transformation in the nature of topological defects by tuning the activity of the system.

  11. Evaluation of performance reference compounds (PRCs) to monitor emerging polar contaminants by polar organic chemical integrative samplers (POCIS) in rivers.

    PubMed

    Carpinteiro, Inmaculada; Schopfer, Adrien; Estoppey, Nicolas; Fong, Camille; Grandjean, Dominique; de Alencastro, Luiz F

    2016-02-01

    In this work, a method combining polar organic chemical integrative samplers (POCIS) and ultraperformance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) was assessed for the determination of two corrosion inhibitors (benzotriazole and methylbenzotriazole), seven pesticides (atrazine, diuron, isoproturon, linuron, metolachlor, penconazole, terbuthylazine), and four pharmaceuticals (carbamazepine, diclofenac, metformin, sulfamethoxazole) in river water. As a first step, two POCIS sorbents, hydrophilic-lipophilic balance (HLB) and Strata X-CW, were compared. The comparison of the uptake profiles of the studied compounds showed that the HLB sorbent provides better uptake (higher sampled amount and better linearity) than Strata X-CW except for the basic compound metformin. Since the sampling rate (R s) of POCIS depends on environmental factors, seven compounds were evaluated as potential performance reference compounds (PRCs) through kinetic experiments. Deisopropylatrazine-d5 (DIA-d5) and, as far as we know, for the first time 4-methylbenzotriazole-d3 showed suitable desorption. The efficiency of both compounds to correct for the effect of water velocity was shown using a channel system in which POCIS were exposed to 2 and 50 cm s(-1). Finally, POCIS were deployed upstream and downstream of agricultural wine-growing and tree-growing areas in the Lienne River and the Uvrier Canal (Switzerland). The impact of the studied areas on both streams could be demonstrated. PMID:26637214

  12. Solid fat content measurement as a substitute for total polar compound analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monitoring of oxidative degradation in frying oils is essential for determining an appropriate discard time. The most reliable method for monitoring the extent of oxidation in edible oils is the determination of total polar compounds. However, this method is time-consuming and not practical to execu...

  13. Solid fat content measurement as an alternative to total polar compound analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monitoring of oxidative degradation in frying oils is essential for determining an appropriate discard time. The most reliable method for monitoring the extent of oxidation in edible oils is the determination of total polar compounds (TPC). However, this method is time-consuming and not practical ...

  14. IDENTIFICATION OF POLAR VOLATILE ORGANIC COMPOUNDS IN CONSUMER PRODUCTS AND COMMON MICROENVIRONMENTS

    EPA Science Inventory

    Polar volatile organic compounds were identified in the headspace of 31 fragrance products such as perfumes, colognes and soaps. About 150 different chemicals were identified in a semiquantitative fashion, using two methods to analyze the headspace: direct injection into a gas ch...

  15. POLAR ORGANIC COMPOUNDS IN FINE PARTICLES FROM THE NEW YORK, NEW JERSEY, AND CONNECTICUT REGIONAL AIRSHED

    EPA Science Inventory

    Five key scientific questions guiding this research were explored. They are given here with results generated from the project.
     
    B.1.        How can polar organic compounds be measured in atmospheric fine particulate matter? Is there potential a...

  16. Sorption of polar and nonpolar aromatic compounds to two humic acids with varied structural heterogeneity

    SciTech Connect

    Sun, H.Y.; Zhu, D.Q.; Mao, J.D.

    2008-12-15

    The major objective of the present study was to evaluate the correlation between structural nature of humic acids (HAs) and sorption affinity of organic compounds with varied polarity. We compared the sorption behavior of three aromatic compounds-nonpolar phenanthrene (PHEN) and 1,2,4,5-tetrachlorobenzene (TeCB) and highly polar 2,4-dichlorophenol (DCP)-to a solid-phase coal humic acid (CHA) and a soil humic acid (SHA) suspended in aqueous solution. The structural nature of HAs was characterized using elemental analysis, ultraviolet absorbance, diffusive reflectance Fourier-transform infrared, and solid-state C-13 nuclear magnetic resonance. The two tested HAs have very different structural properties: CHA consists primarily of poly(methylene)-rich aliphatics with high aromatic content and some COO/N-C=O but low polarity, while SHA consists of young materials of lignin, carbohydrates, and peptides with high polarity. In response to the structural heterogeneity of HAs, sorption of nonpolar and more hydrophobic solutes (PHEN, TeCB) to CHA is much greater than that to SHA because of the predominance of hydrophobic effects; however, disparities in sorption affinity between the two HAs become smaller for polar and less hydrophobic DCP because of the major role played by polar interactions. The influence of pH on the sorption of different solutes to the two HAs was also discussed. The results of the present work highlight the importance of structural heterogeneity of both solutes and HAs in the sorption process.

  17. Polarization rotation and coupling between silicon waveguide and hybrid plasmonic waveguide

    PubMed Central

    Kim, Sangsik; Qi, Minghao

    2015-01-01

    We present a polarization rotation and coupling scheme that rotates a TE0 mode in a silicon waveguide and simultaneously couples the rotated mode to a hybrid plasmonic (HP0) waveguide mode. Such a polarization rotation can be realized with a partially etched asymmetric hybrid plasmonic waveguide consisting of a silicon strip waveguide, a thin oxide spacer, and a metal cap made from copper, gold, silver or aluminum. Two implementations, one with and one without the tapering of the metal cap are presented, and different taper shapes (linear and exponential) are also analyzed. The devices have large 3 dB conversion bandwidths (over 200 nm at near infrared) and short length (< 5 μm), and achieve a maximum coupling factor of ∼ 78% with a linearly tapered silver metal cap. PMID:25969038

  18. Controlled field evaluation of water flow rate effects on sampling polar organic compounds using polar organic chemical integrative samplers.

    PubMed

    Li, Hongxia; Vermeirssen, Etiënne L M; Helm, Paul A; Metcalfe, Chris D

    2010-11-01

    The uptake of polar organic contaminants into polar organic chemical integrative samplers (POCIS) varies with environmental factors, such as water flow rate. To evaluate the influence of water flow rate on the uptake of contaminants into POCIS, flow-controlled field experiments were conducted with POCIS deployed in channel systems through which treated sewage effluent flowed at rates between 2.6 and 37 cm/s. Both pharmaceutical POCIS and pesticide POCIS were exposed to effluent for 21 d and evaluated for uptake of pharmaceuticals and personal care products (PPCPs) and endocrine disrupting substances (EDS). The pesticide POCIS had higher uptake rates for PPCPs and EDS than the pharmaceutical POCIS, but there are some practical advantages to using pharmaceutical POCIS. The uptake of contaminants into POCIS increased with flow rate, but these effects were relatively small (i.e., less than twofold) for most of the test compounds. There was no relationship observed between the hydrophobicity (log octanol/water partition coefficient, log K(OW)) of model compounds and the effects of flow rate on the uptake kinetics by POCIS. These data indicate that water flow rate has a relatively minor influence on the accumulation of PPCPs and EDS into POCIS. PMID:20865700

  19. Anomalous temperature dependence of gas chromatographic retention indices of polar compounds on non-polar stationary phases.

    PubMed

    Pavlovskii, Alexander A; Héberger, Károly; Zenkevich, Igor G

    2016-05-01

    Increasing the reliability of both GC and GC-MS identification requires appropriate interlaboratory reproducibility of gas chromatographic retention indices (I). Known temperature dependence, I(T), is the main source of non-reproducibility of these parameters. It can be approximated with a simple linear function I(T). However, since mid-1990s-beginning of 2000s some examples of anomalous temperature dependence, I(T), preferably for polar analytes on non-polar stationary phases were revealed independently by different authors. The effect implies the variations in the sign of the temperature coefficients β=dI/dT for selected compounds and, hence, the appearance of the I-extrema (usually, minima). The current work provides evidence that the character of the anomalous I(Т) dependences (ascending, descending, or with extrema) is strongly influenced by the amounts of analytes injected into the chromatographic column, but these anomalies appeared not to be connected directly with the mass overloading of separation systems. The physicochemical model is proposed to describe the observed anomalies of I(T) dependence. This model is based on three previously known principles of chromatography, namely: The superposition of these objectives allows understanding both the unusual temperature dependence of retention indices, and the influence of the amounts of polar analytes injected into GC column on the parameters of this dependence. PMID:27062719

  20. Remote preparation of single-photon "hybrid" entangled and vector-polarization States.

    PubMed

    Barreiro, Julio T; Wei, Tzu-Chieh; Kwiat, Paul G

    2010-07-16

    Quantum teleportation faces increasingly demanding requirements for transmitting large or even entangled systems. However, knowledge of the state to be transmitted eases its reconstruction, resulting in a protocol known as remote state preparation. A number of experimental demonstrations to date have been restricted to single-qubit systems. We report the remote preparation of two-qubit "hybrid" entangled states, including a family of vector-polarization beams. Our single-photon states are encoded in the photon spin and orbital angular momentum. We reconstruct the states by spin-orbit state tomography and transverse polarization tomography. The high fidelities achieved for the vector-polarization states opens the door to optimal coupling of down-converted photons to other physical systems, such as an atom, as required for scalable quantum networks, or plasmons in photonic nanostructures. PMID:20867752

  1. Design, synthesis and anticancer activity of novel hybrid compounds between benzofuran and N-aryl piperazine.

    PubMed

    Mao, Ze-Wei; Zheng, Xi; Lin, Yu-Ping; Hu, Chun-Yan; Wang, Xiu-Li; Wan, Chun-Ping; Rao, Gao-Xiong

    2016-08-01

    A series of novel hybrid compounds between benzofuran and N-aryl piperazine have been designed and prepared. These derivatives were evaluated for their in vitro anti-tumor activity against a panel of human tumor cell lines by MTT assay. The results demonstrated that amide derivatives were more bioactive than sulfonamide compounds in general, and that chloro or trifluoromethyl substituent was vital for modulating cytotoxic activity. In particular, compound 13 was found to be the most potent compound against 4 strains human tumor cell lines, and exhibited cytotoxic activity selectively against Hela (0.03μM). PMID:27371110

  2. Development of high-performance alkali-hybrid polarized 3He targets for electron scattering

    NASA Astrophysics Data System (ADS)

    Singh, Jaideep T.; Dolph, P. A. M.; Tobias, W. A.; Averett, T. D.; Kelleher, A.; Mooney, K. E.; Nelyubin, V. V.; Wang, Yunxiao; Zheng, Yuan; Cates, G. D.

    2015-05-01

    Background: Polarized 3He targets have been used as effective polarized neutron targets for electron scattering experiments for over twenty years. Over the last ten years, the effective luminosity of polarized 3He targets based on spin-exchange optical pumping has increased by over an order of magnitude. This has come about because of improvements in commercially-available lasers and an improved understanding of the physics behind the polarization process. Purpose: We present the development of high-performance polarized 3He targets for use in electron scattering experiments. Improvements in the performance of polarized 3He targets, target properties, and operating parameters are documented. Methods: We utilize the technique of alkali-hybrid spin-exchange optical pumping to polarize the 3He targets. Spectrally narrowed diode lasers used for the optical pumping greatly improved the performance. A simulation of the alkali-hybrid spin-exchange optical pumping process was developed to provide guidance in the design of the targets. Data was collected during the characterization of 24 separate glass target cells, each of which was constructed while preparing for one of four experiments at Jefferson Laboratory in Newport News, Virginia. Results: From the data obtained we made determinations of the so-called X -factors that quantify a temperature-dependent and as-yet poorly understood spin-relaxation mechanism that limits the maximum achievable 3He polarization to well under 100%. The presence of the X -factor spin-relaxation mechanism was clearly evident in our data. Good agreement between the simulation and the actual target performance was obtained by including details such as off-resonant optical pumping. Included in our results is a measurement of the K -3He spin-exchange rate coefficient kseK=(7.46 ±0.62 ) ×10-20cm3/s over the temperature range 503 K to 563 K. Conclusions: In order to achieve high performance under the operating conditions described in this paper

  3. Separation of polar compounds using a flexible metal-organic framework

    SciTech Connect

    Motkuri, Radha K.; Thallapally, Praveen K.; Annapureddy, Harsha V.; Dang, Liem X.; Krishna, Rajamani; Nune, Satish K.; Fernandez, Carlos A.; Liu, Jian; McGrail, B. Peter

    2015-01-01

    A flexible metal-organic framework constructed from a flexible linker is shown to possess the capability of separating mixtures of polar compounds by exploiting the differences in the saturation capacities of the constituents. The separation possibilities with the flexible MOF include mixtures of propanol isomers, and various azeotropes. Transient breakthrough simulations show that these sorption-based separations are in favor of the component with higher saturation capacity.

  4. From hybrid compounds to targeted drug delivery in antimalarial therapy.

    PubMed

    Oliveira, Rudi; Miranda, Daniela; Magalhães, Joana; Capela, Rita; Perry, Maria J; O'Neill, Paul M; Moreira, Rui; Lopes, Francisca

    2015-08-15

    The discovery of new drugs to treat malaria is a continuous effort for medicinal chemists due to the emergence and spread of resistant strains of Plasmodium falciparum to nearly all used antimalarials. The rapid adaptation of the malaria parasite remains a major limitation to disease control. Development of hybrid antimalarial agents has been actively pursued as a promising strategy to overcome the emergence of resistant parasite strains. This review presents the journey that started with simple combinations of two active moieties into one chemical entity and progressed into a delivery/targeted system based on major antimalarial classes of drugs. The rationale for providing different mechanisms of action against a single or additional targets involved in the multiple stages of the parasite's life-cycle is highlighted. Finally, a perspective for this polypharmacologic approach is presented. PMID:25913864

  5. A compact polarization converter for silicon-based slot waveguides using a hybrid plasmonic effect

    NASA Astrophysics Data System (ADS)

    Xu, Yin; Xiao, Jinbiao; Sun, Xiaohan

    2014-08-01

    A compact polarization converter for silicon-based slot waveguides is proposed, in which a metal strip of silver (Ag) with a right-angled cross section located at the upper-right corner of the slot waveguide is embedded in its upper claddings. Owing to the characteristics of the introduced asymmetric hybrid plasmonic waveguide, the modal hybridness is highly enhanced and the optimal optical axis rotation angle, 45°, is realized by optimizing the location and size of the Ag, resulting in high polarization conversion efficiency (PCE). Numerical results show that a polarization converter of 15.2 μm in length, operating at a wavelength of 1.55 μm for TM-to-TE conversion, is achieved, where the PCE and insertion loss are 96.9% and 0.7 dB, respectively, and bandwidth with PCE >92% is ˜67 nm (from 1524 to 1591 nm), covering the entire C-band. Moreover, fabrication tolerances to the structural parameters and field evolution along the propagation distance are investigated.

  6. Stable multi-wavelength fiber laser based on a compounded nonlinear polarization rotation effect

    NASA Astrophysics Data System (ADS)

    Zou, Hui; Lou, Shuqin; Ma, Jianli; Su, Wei; Han, Bolin; Shen, Xiao

    2014-11-01

    A stable multi-wavelength polarization-maintaining erbium-doped fiber (PM-EDF) laser with high signal-to-noise ratio (SNR) based on a compounded nonlinear polarization rotation effect (CNPRE) is proposed and demonstrated. In order to effectively reduce homogeneous broadening of EDF and then to the alleviate mode competition, two sandwich configurations formed by a polarization dependent isolator (PDI) or a segment of single-mode fiber sandwiched between two polarization controllers (PC), are introduced into the ring cavity to generate the CNPRE. A home-made asymmetry twin-core fiber (ATCF) is also incorporated in the ring cavity as a comb filter. With only 150 mW pump power, there are up to 45-wavelengths lasing with the approximate amplitude in a 3 dB bandwidth generated at room temperature. The wavelength spacing between the adjacent peaks is 0.29 nm and the highest SNRs reach 41.5 dB by optimizing the state of polarization of PCs. The power fluctuation and wavelength shift for each lasing wavelength are less than 0.05 dB and 0.02 nm, respectively. This indicates that the proposed multi-wavelength fiber laser can be stably operated at room temperature.

  7. Distribution of aroma volatile compounds in tangerine hybrids and proposed inheritance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the desirable combination of sugars and acids, volatile compounds contribute to the essential organoleptic attributes of citrus. This study evaluated the aroma volatiles of 20 tangerine hybrids of the University of Florida breeding program. Volatiles were sampled from hand-squeezed juice by hea...

  8. Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

    PubMed Central

    Bassanini, Ivan; Hult, Karl

    2015-01-01

    Summary Dicarboxylic acids and their derivatives (esters and anhydrides) have been used as acylating agents in lipase-catalyzed reactions in organic solvents. The synthetic outcomes have been dimeric or hybrid derivatives of bioactive natural compounds as well as functionalized polyesters. PMID:26664578

  9. Study of coumarin-resveratrol hybrids as potent antioxidant compounds.

    PubMed

    Matos, Maria J; Mura, Francisco; Vazquez-Rodriguez, Saleta; Borges, Fernanda; Santana, Lourdes; Uriarte, Eugenio; Olea-Azar, Claudio

    2015-01-01

    In the present work we synthesized a selected series of hydroxylated 3-phenylcoumarins 5-8, with the aim of evaluating in detail their antioxidant properties. From an in depth study of the antioxidant capacity data (ORAC-FL, ESR, CV and ROS inhibition) it was concluded that these derivatives are very good antioxidants, with very interesting profiles in all the performed assays. The study of the effect of the number and position of the hydroxyl groups on the antioxidant activity was the principal aim of this study. In particular, 7-hydroxy-3-(3'-hydroxy)phenylcoumarin (8) proved to be the most active and effective antioxidant of the selected series in four of the performed assays (ORAC-FL = 11.8, capacity of scavenging hydroxyl radicals = 54%, Trolox index = 2.33 and AI30 index = 0.18). However, the presence of two hydroxyl groups on this molecule did not increase greatly the activity profile. Theoretical evaluation of ADME properties of all the derivatives was also carried out. All the compounds can act as potential candidates for preventing or minimizing the free radical overproduction in oxidative-stress related diseases. These preliminary findings encourage us to perform a future structural optimization of this family of compounds. PMID:25690290

  10. Hybrid energy storage systems utilizing redox active organic compounds

    DOEpatents

    Wang, Wei; Xu, Wu; Li, Liyu; Yang, Zhenguo

    2015-09-08

    Redox flow batteries (RFB) have attracted considerable interest due to their ability to store large amounts of power and energy. Non-aqueous energy storage systems that utilize at least some aspects of RFB systems are attractive because they can offer an expansion of the operating potential window, which can improve on the system energy and power densities. One example of such systems has a separator separating first and second electrodes. The first electrode includes a first current collector and volume containing a first active material. The second electrode includes a second current collector and volume containing a second active material. During operation, the first source provides a flow of first active material to the first volume. The first active material includes a redox active organic compound dissolved in a non-aqueous, liquid electrolyte and the second active material includes a redox active metal.

  11. Embryo selection in IVF: is polar body array comparative genomic hybridization accurate enough?

    PubMed

    Scriven, Paul N; Ogilvie, Caroline Mackie; Khalaf, Yacoub

    2012-04-01

    The emergence of the array comparative genomic hybridization technique (aCGH) is considered an advance in preimplantation genetic testing. Analysis of the recently published pilot study using polar body aCGH indicates that the test accuracy compares favourably with the fluorescence in situ hybridization technique although a substantial number of euploid zygotes are still likely to be excluded incorrectly. A sound argument against selection in principle has recently been published, based on accumulating evidence that potentially all embryos can now be cryopreserved and transferred in subsequent frozen replacement cycles without impairing pregnancy rates. We suggest that vitrification and serial transfer without testing are likely to give patients the best chance for a successful pregnancy, and avoid the use of an expensive technology. PMID:22328558

  12. Hybrid K-Rb Spin Exchange Optical Pumping Cells for the Polarization of ^3He

    NASA Astrophysics Data System (ADS)

    Couture, Alex; Daniels, Tim; Arnold, Charles; Clegg, Tom

    2006-11-01

    We are transitioning from polarizing ^3He using optical pumping cells charged with pure Rb to using a mixture of Rb and K, lean in Rb. The reason for this is the spin exchange efficiency between K and ^3He is an order of magnitude greater than that of Rb and ^3He. Also the spin exchange cross section between Rb and K is very large, which leads to a very fast rate of polarization transfer from Rb to K. Thus by optically pumping using a standard 795 nm Rb laser on a hybrid K-Rb cell, we can obtain significant improvements in spin-up time as well as improvements in overall polarization.[1] We produce hybrid pumping cells at TUNL using a filling station consisting of an oven and a turbo pumping station to bake out and pump away any impurities in the cells. The alkali metals are introduced into the pumping cells from a Y-shaped manifold with a separate retort for each alkali. We are able to determine the ratio of K to Rb in the vapor using white light absorption spectroscopy. Light from a halogen light bulb is incident upon the heated cell and enters a spectrometer beyond. We examine the relative sizes of the D1 and D2 absorption lines for the two alkali metals. We will have data comparing hybrid cells to pure Rb cells, GE-180 cells to Pyrex, and are working to obtain comparative performance data for spectrally unnarrowed and narrowed lasers. Our latest results will be reported. [1] E. Babcock, et al. (2003) Phys. Rev. Letter Vol. 91, Num.12, 123003

  13. Atomic origin of the spin-polarization of the Co2FeAl Heusler compound

    NASA Astrophysics Data System (ADS)

    Liang, Jaw-Yeu; Lam, Tu-Ngoc; Lin, Yan-Cheng; Chang, Shu-Jui; Lin, Hong-Ji; Tseng, Yuan-Chieh

    2016-02-01

    Using synchrotron x-ray techniques, we studied the Co2FeAl spin-polarization state that generates the half-metallicity of the compound during an A2 (low-spin)  →  B2 (high-spin) phase transition. Given the advantage of element specificity of x-ray techniques, we could fingerprint the structural and magnetic cross-reactions between Co and Fe within a complex Co2FeAl structure deposited on a MgO (0 0 1) substrate. X-ray diffraction and extended x-ray absorption fine structure investigations determined that the Co atoms preferably populate the (1/4,1/4,1/4) and (3/4,3/4,3/4) sites during the development of the B2 phase. X-ray magnetic spectroscopy showed that although the two magnetic elements were ferromagnetically coupled, they interacted in a competing manner via a charge-transfer effect, which enhanced Co spin polarization at the expense of Fe spin polarization during the phase transition. This means that the spin-polarization of Co2FeAl was electronically dominated by Fe in A2 whereas the charge transfer turned the dominance to Co upon B2 formation. Helicity-dependent x-ray absorption spectra also revealed that only the minority state of Co/Fe was involved in the charge-transfer effect whereas the majority state was independent of it. Despite an overall increase of Co2FeAl magnetization, the charge-transfer effect created an undesired trade-off during the Co-Fe exchange interactions, because of the presence of twice as many X sites (Co) as Y sites (Fe) in the Heusler X 2 YZ formula. This suggests that the spin-polarization of Co2FeAl is unfortunately regulated by compromising the enhanced X (Co) sites and the suppressed Y (Fe) sites, irrespective of the development of the previously known high-spin-polarization phase of B2. This finding provides a possible cause for the limited half-metallicity of Co2FeAl discovered recently. Electronic tuning between the X and Y sites is necessary to further increase the spin-polarization, and likely the half

  14. Emissions of carbon species, organic polar compounds, potassium, and mercury from prescribed burning activities

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Obrist, D.; Zielinska, B.; Gerler, A.

    2012-04-01

    Biomass burning is an important emission source of pollutants to the atmosphere, but few studies have focused on the chemical composition of emissions from prescribed burning activities. Here we present results from a sampling campaign to quantify particulate-phase emissions from various types of prescribed fires including carbon species (Elemental Carbon: EC; Organic Carbon: OC; and Total Carbon: TC); polar organic compounds (12 different compounds and four functional classes); water-soluble potassium (K+); and mercury (Hg). We measured emissions from the following types of prescribed biomass burning in the Lake Tahoe basin located on the California/Nevada border: (i) log piles stacked and dried in the field; (ii) log piles along with green understory vegetation; and (iii) understory green vegetation and surface litter; further emissions were collected from burns conducted in a wood stove: (iv) dried wooden logs; (v) green foliage of understory vegetation collected from the field; and (vi) surface organic litter collected from the field; finally, samples were also taken from (vii) ambient air in residential areas during peak domestic wood combustion season. Results show that OC/EC ratios of prescribed burns in the field ranged from 4 to 10, but lower values (around 1) were observed in controlled stove fires. These results are consistent with an excess of OC emissions over EC found in wildfires. OC/EC ratios, however, showed clear separations between controlled wood stove combustion (higher EC) and prescribed burns in the field (lower EC). We attribute this difference to a higher combustion temperatures and dominance of flaming combustion in wood stove fires. OC positively and linearly correlated to the sum of polar organic compounds across all burn types (r2 of 0.82). The most prevalent group of polar compounds emitted during prescribed fires was resin acids (dehydroabietic, pimaric, and abietic acids), followed by levoglucosan plus mannositol. Negligible

  15. [Corrected Title: Solid-Phase Extraction of Polar Compounds from Water] Automated Electrostatics Environmental Chamber

    NASA Technical Reports Server (NTRS)

    Sauer, Richard; Rutz, Jeffrey; Schultz, John

    2005-01-01

    A solid-phase extraction (SPE) process has been developed for removing alcohols, carboxylic acids, aldehydes, ketones, amines, and other polar organic compounds from water. This process can be either a subprocess of a water-reclamation process or a means of extracting organic compounds from water samples for gas-chromatographic analysis. This SPE process is an attractive alternative to an Environmental Protection Administration liquid-liquid extraction process that generates some pollution and does not work in a microgravitational environment. In this SPE process, one forces a water sample through a resin bed by use of positive pressure on the upstream side and/or suction on the downstream side, thereby causing organic compounds from the water to be adsorbed onto the resin. If gas-chromatographic analysis is to be done, the resin is dried by use of a suitable gas, then the adsorbed compounds are extracted from the resin by use of a solvent. Unlike the liquid-liquid process, the SPE process works in both microgravity and Earth gravity. In comparison with the liquid-liquid process, the SPE process is more efficient, extracts a wider range of organic compounds, generates less pollution, and costs less.

  16. Magnetic compound refractive lens for focusing and polarizing cold neutron beams.

    PubMed

    Littrell, K C; te Velthuis, S G E; Felcher, G P; Park, S; Kirby, B J; Fitzsimmons, M R

    2007-03-01

    Biconcave cylindrical lenses are used to focus beams of x rays or neutrons using the refractive properties of matter. In the case of neutrons, the refractive properties of magnetic induction can similarly focus and simultaneously polarize the neutron beam without the concomitant attenuation of matter. This concept of a magnetic refractive lens was tested using a compound lens consisting of 99 pairs of cylindrical permanent magnets. The assembly successfully focused the intensity of a white beam of cold neutrons of one spin state at the detector, while defocusing the other. This experiment confirmed that a lens of this nature may boost the intensity locally by almost an order of magnitude and create a polarized beam. An estimate of the performance of a more practically dimensioned device suitable for incorporation in reflectometers and slit-geometry small angle scattering instruments is given. PMID:17411211

  17. Polarity, selectivity and performance of hydrophilic organic/salt-containing aqueous two-phase system on counter-current chromatography for polar compounds.

    PubMed

    Liu, Dan; Hong, Zhilai; Gao, Mingzhe; Wang, Zhixin; Gu, Ming; Zhang, Xiaozhe; Xiao, Hongbin

    2016-05-27

    The essential attributes of a solvent system for separation polar compounds on CCC are polarity, selectively and performance. Here, hydrophilic organic/salt-containing aqueous two-phase system (HO/S TPS) was evaluated as an alternative solvent system for CCC separation of polar compounds. Polarity measurements based on Rohrschneider-Snyder parameter was developed as quantitative assessing the polarity of HO/S TPS and comparing with an organic/aqueous system. All investigated 1-butanol/ethanol/saturated ammonium sulfate solution/water (BEAsWat) and 1-butanol/ethanol/saturated dipotassium hydrogen phosphate solution/water (BEDhpWat) systems with polarity values of organic phase from 4.5 to 6.8, were more polar than chloroform/methanol/water (1/1/1). The considerable water content of BEAsWat and BEDhpWat (0/1/1/1/) was 45.4 and 42.6% (w%) of hydrophilic organic phase, and 66.4 and 51.2% (w%) of salt-containing aqueous phase, respectively, closed to conventional aqueous two-phase system. Therefore, the polarity of HO/S TPS is in the middle of organic/aqueous and aqueous two-phase system. The LogKC values of twenty four polar compounds as model mixture confirmed that the polarities of HO/S TPSs were matched to that of the polar compounds and shown to be a very selective technique capable of separating positional isomers. Moreover, BEAsWat and BEDhpWat systems can be easily retained in CCC column with suitable elution mode. The hydrodynamic behavior reversion of HO/S TPS on hydrodynamic CCC was observed and was tentatively explained based on the density difference. Finally, caffeoylquinic acid isomers and dihydroxybenzoic acid isomers were successfully separated with HO/S TPS on CCC, respectively. Those results demonstrate that HO/S TPS on CCC is a performant and stable way to separate polar compounds from natural products. PMID:27131958

  18. Kilowatt-level near-diffraction-limited and linear-polarized Ytterbium-Raman hybrid nonlinear amplifier based on polarization selection loss mechanism.

    PubMed

    Ma, Pengfei; Zhang, Hanwei; Huang, Long; Wang, Xiaolin; Zhou, Pu; Liu, Zejin

    2015-10-01

    Ytterbium-Raman cascaded oscillators with linearly polarized output are designed and achieved based on polarization selection loss (PSL) mechanism for the first time. The 1120 nm laser cavity is designed with fully non polarization-maintained (NPM) fiber Bragg gratings (FBGs) and NPM active fiber while the 1080 nm laser cavity is designed based on polarization-maintained (PM) FBGs and PM active fiber. By using PSL mechanism in 1080 nm cavity, even with fully NPM 1120 nm cavity, both linear-polarized 1120 nm and 1080 nm lasers are achieved in the output port of the cascaded oscillators. Based on the new designed cascaded seeds, a high power polarization-maintained Yb-Raman hybrid nonlinear amplifier is established for further power scaling of the 1120 nm laser. In the nonlinear amplifier, only 21-meter-long active fiber and 1.5-meter-long passive fiber is used for power transferring from 1080 nm to 1120 nm. Output power of 1181 W is achieved at central wavelength of 1120 nm with the M(2) factor of <1.2 and polarization-extinction ratio (PER) of 18.2 dB. As far as we known, the output power of this all fiber format is the highest one in 1120 nm with linear polarization. This type of high power Yb-Raman nonlinear amplifier design with linear polarization can be further extended to Yb-Raman amplifying the wavelength range of 1100-1200 nm. PMID:26480163

  19. Hybrid T-helper cells: stabilizing the moderate center in a polarized system.

    PubMed

    Huang, Sui

    2013-01-01

    Polarization of cell phenotypes, a common strategy to achieve cell type diversity in metazoa, results from binary cell-fate decisions in the branching pedigree of development. Such "either-or" fate decisions are controlled by two opposing cell fate-determining transcription factors. Each of the two distinct "master regulators" promotes differentiation of its respective sister lineage. But they also suppress one other, leading to their mutually exclusive expression in the two ensuing lineages. Thus, promiscuous coexistence of the antagonist regulators in the same cell, the hallmark of the common "undecided" progenitor of two sister lineages, is considered unstable. This antagonism ensures robust polarization into two discretely distinct cell types. But now the immune system's T-helper (Th) cells and their two canonical subtypes, Th1 and Th2 cells, tell a different story, as revealed in three papers recently published in PLOS Biology. The intermediate state that co-expresses the two opposing master regulators of the Th1 and Th2 subtypes, T-bet and Gata3, is highly stable and is not necessarily an undecided precursor. Instead, the Th1/Th2 hybrid cell is a robust new type with properties of both Th1 and Th2 cells. These hybrid cells are functionally active and possess the benefit of moderation: self-limitation of effector T cell function to prevent excessive inflammation, a permanent risk in host defense that can cause tissue damage or autoimmunity. Gene regulatory network analysis suggests that stabilization of the intermediate center in a polarizing system can be achieved by minor tweaking of the architecture of the mutual suppression gene circuit, and thus is a design option readily available to evolution. PMID:23976879

  20. Isotopic analyses of nitrogenous compounds from the Murchison meteorite: ammonia, amines, amino acids, and polar hydrocarbons

    NASA Technical Reports Server (NTRS)

    Pizzarello, S.; Feng, X.; Epstein, S.; Cronin, J. R.

    1994-01-01

    The combined volatile bases (ammonia, aliphatic amines, and possibly other bases), ammonia, amino acids, and polar hydrocarbons were prepared from the Murchison meteorite for isotopic analyses. The volatile bases were obtained by cryogenic transfer after acid-hydrolysis of a hot-water extract and analyzed by combined gas chromatography-mass spectrometry of pentafluoropropionyl derivatives. The aliphatic amines present in this preparation comprise a mixture that includes both primary and secondary isomers through C5 at a total concentration of > or = 100 nmoles g-1. As commonly observed for meteoritic organic compounds, almost all isomers through C5 are present, and the concentrations within homologous series decrease with increasing chain length. Ammonia was chromatographically separated from the other volatile bases and found at a concentration of 1.1-1.3 micromoles g-1 meteorite. The ammonia analyzed includes contributions from ammonium salts and the hydrolysis of extractable organic compounds, e.g., carboxamides. Stable isotope analyses showed the volatile bases to be substantially enriched in the heavier isotopes, relative to comparable terrestrial compounds delta D < or = +1221%; delta 13C = +22%; delta 15N = +93%). Ammonia, per se, was found to have a somewhat lower delta 15N value (+69%) than the total volatile bases; consequently, a higher delta 15N (>93%) can be inferred for the other bases, which include the amines. Solvent-extractable polar hydrocarbons obtained separately were found to be enriched in 15N (delta 15N = +104%). Total amino acids, prepared from a hydrolyzed hot-water extract by cation exchange chromatography, gave a delta 15N of +94%, a value in good agreement with that obtained previously. Nitrogen isotopic data are also given for amino acid fractions separated chromatographically. The delta 15N values of the Murchison soluble organic compounds analyzed to date fall within a rather narrow range (delta 15N = +94 +/- 8%), an observation

  1. Configuration-dependent hybridization in electron spectroscopies of Ce-based compounds

    SciTech Connect

    Witkowski, N.; Bertran, F.; Malterre, D.

    1997-12-01

    In this paper, we analyze Ce 3d core-level photoemission and inverse-photoemission spectra in the framework of the single-impurity Anderson model. We show that the Gunnarsson-Sch{umlt o}nhammer model generally used to describe spectroscopic properties of Ce-based systems cannot account for the description of core-hole photoemission and inverse-photoemission spectra with the same set of parameters. By introducing 4f configuration-dependent hybridization terms, the situation is significantly improved, and a satisfactory agreement between experimental and calculated spectra is obtained. This result shows that, in contrast to what was previously claimed for highly hybridized compounds, the spectroscopic data of cerium compounds can be described in the framework of the single-impurity Anderson model. {copyright} {ital 1997} {ital The American Physical Society}

  2. Metal-VO2 hybrid grating structure for a terahertz active switchable linear polarizer

    NASA Astrophysics Data System (ADS)

    Shin, Jun-Hwan; Moon, Kiwon; Lee, Eui Su; Lee, Il-Min; Park, Kyung Hyun

    2015-08-01

    An active terahertz (THz) wave hybrid grating structure of Au/Ti metallic grating on VO2/Al2O3 (0001) was fabricated and evaluated. In our structure, it is shown that the metallic gratings on the VO2 layer strengthen the metallic characteristics to enhance the contrast of the metallic and dielectric phases of a VO2-based device. Especially, the metal grating-induced optical conductivity of the device is greatly enhanced, three times more than that of a metallic phase of bare VO2 films in the 0.1-2.0 THz spectral range. As an illustrative example, we fabricated an actively on/off switchable THz linear polarizer. The fabricated device has shown commercially comparable values in degree of polarization (DOP) and extinction ratio (ER). A high value of 0.89 in the modulation depth (MD) for the transmission field amplitude, superior to other THz wave modulators, is achieved. The experimental results show that the fabricated device can be highly useful in many applications, including active THz linear polarizers, THz wave modulators and variable THz attenuators.

  3. Metal-VO2 hybrid grating structure for a terahertz active switchable linear polarizer.

    PubMed

    Shin, Jun-Hwan; Moon, Kiwon; Lee, Eui Su; Lee, Il-Min; Park, Kyung Hyun

    2015-08-01

    An active terahertz (THz) wave hybrid grating structure of Au/Ti metallic grating on VO2/Al2O3 (0001) was fabricated and evaluated. In our structure, it is shown that the metallic gratings on the VO2 layer strengthen the metallic characteristics to enhance the contrast of the metallic and dielectric phases of a VO2-based device. Especially, the metal grating-induced optical conductivity of the device is greatly enhanced, three times more than that of a metallic phase of bare VO2 films in the 0.1-2.0 THz spectral range. As an illustrative example, we fabricated an actively on/off switchable THz linear polarizer. The fabricated device has shown commercially comparable values in degree of polarization (DOP) and extinction ratio (ER). A high value of 0.89 in the modulation depth (MD) for the transmission field amplitude, superior to other THz wave modulators, is achieved. The experimental results show that the fabricated device can be highly useful in many applications, including active THz linear polarizers, THz wave modulators and variable THz attenuators. PMID:26183858

  4. Comparison of two extraction procedures for the assessment of sediment genotoxicity: implication of polar organic compounds.

    PubMed

    Di Giorgio, Carole; Malleret, Laure; Gueydon-Morin, Céline; Rigaud, Sylvain; De Méo, Michel

    2011-10-01

    Four sediment samples (Vaïne Airport VA, Vaïne Center VC, Vaïne North VN and Reference North RN) were collected in the Berre lagoon (France). Sediments were analyzed for polycyclic aromatic hydrocarbons (PAHs) by use of pressurized fluid extraction with a mixture of hexane/dichloromethane followed by HPLC with fluorescence detection analysis. Organic pollutants were also extracted with two solvents for subsequent evaluation of their genotoxicity: a hexane/dichloromethane mixture intended to select non-polar compounds such as PAHs, and 2-propanol intended to select polar contaminants. Sediment extracts were assessed by the Salmonella/microsome mutagenicity test with Salmonella typhimurium TA98+S9 mix and YG1041±S9 mix. Extracts were also assessed for their DNA-damaging activity and their clastogenic/aneugenic properties by the comet assay and the micronucleus test with Chinese Hamster ovary (CHO) cells. The PAH concentrations were 611ngg(-1)dw, 1341ngg(-1) dw, 613ngg(-1)dw and 482ngg(-1)dw for VA, VC, VN and RN, respectively. Two genotoxic profiles were observed, depending on the extraction procedure. All the non-polar extracts were mutagenic for TA98+S9 mix, and VA, VC, VN sediment samples exerted a significant DNA-damaging and clastogenic activity in the presence of S9 mix. All the polar extracts appeared mutagenic for TA98+S9 mix and YG104±S9 mix, and VA, VC, VN were genotoxic and clastogenic both with and without S9 mix. These results indicate that the genotoxic and mutagenic activities mainly originated from PAHs in the non-polar extracts, while these activities came from other genotoxic contaminants, such as aromatic amines and nitroarenes, in the polar extracts. This study focused on the important role of uncharacterized polar contaminants such as nitro-PAHs or aromatic amines in the global mutagenicity of sediments. The necessity to use appropriate extraction solvents to accurately evaluate the genotoxic hazard of aquatic sediments is also highlighted

  5. Linear polarizer local characterizations by polarimetric imaging for applications to polarimetric sensors for torque measurement for hybrid cars

    NASA Astrophysics Data System (ADS)

    Georges, F.; Remouche, M.; Meyrueis, P.

    2011-06-01

    Usually manufacturer's specifications do not deal with the ability of linear sheet polarizers to have a constant transmittance function over their geometric area. These parameters are fundamental for developing low cost polarimetric sensors(for instance rotation, torque, displacement) specifically for hybrid car (thermic + electricity power). It is then necessary to specially characterize commercial polarizers sheets to find if they are adapted to this kind of applications. In this paper, we present measuring methods and bench developed for this purpose, and some preliminary characterization results. We state conclusions for effective applications to hybrid car gearbox control and monitoring.

  6. A comparison of concentration techniques for the analysis of polar compounds in canister samples

    SciTech Connect

    Cardin, D.B.; Deschenes, J.T.

    1994-12-31

    The analysis of polar volatile organic compounds (PVOCs) in ambient air by GC/MS requires sample preconcentration to achieve 0.1 ppb detection limits. Necessary sample volumes can exceed 300 c resulting in the co-collection of approximately 3--6 {micro}l of water, depending on the humidity of the sample. This much water will degrade column performance and will cause signal attenuation in benchtop mass spectrometers making quantification of target analytes difficult. A concentration system utilizing yet a third water management technique called Cold Trap Dehydration (CTD) will be presented. Using this technique, water can be substantially eliminated without loss of polar VOCs of interest. CO{sub 2} is also eliminated before GC/MS injection resulting in superior chromatographic performance and a more consistent GC/MS response for the extreme light VOCs. The preconcentrator uses the same hardware trapping configuration for Cold Trap Dehydration as it does for Automated 2-Dimensional Chromatography and Microscale Purge and Trap, and can select any one of the three applications under software control. To determine which approach is best for TO14 and CAAA Title 3 compounds, all three water management procedures will be examined and compared. Data will be presented showing detection limits and %RSD`s from the analysis of PVOCs in canisters using the 3-stage Entech 2000/2016CM Automated preconcentration system and an HP 5972 GC/MS.

  7. Compound gravity receptor polarization vectors evidenced by linear vestibular evoked potentials

    NASA Technical Reports Server (NTRS)

    Jones, S. M.; Jones, T. A.; Bell, P. L.; Taylor, M. J.

    2001-01-01

    The utricle and saccule are gravity receptor organs of the vestibular system. These receptors rely on a high-density otoconial membrane to detect linear acceleration and the position of the cranium relative to Earth's gravitational vector. The linear vestibular evoked potential (VsEP) has been shown to be an effective non-invasive functional test specifically for otoconial gravity receptors (Jones et al., 1999). Moreover, there is some evidence that the VsEP can be used to independently test utricular and saccular function (Taylor et al., 1997; Jones et al., 1998). Here we characterize compound macular polarization vectors for the utricle and saccule in hatchling chickens. Pulsed linear acceleration stimuli were presented in two axes, the dorsoventral (DV, +/- Z axis) to isolate the saccule, and the interaural (IA, +/- Y axis) to isolate the utricle. Traditional signal averaging was used to resolve responses recorded from the surface of the skull. Latency and amplitude of eighth nerve components of the linear VsEP were measured. Gravity receptor responses exhibited clear preferences for one stimulus direction in each axis. With respect to each utricular macula, lateral translation in the IA axis produced maximum ipsilateral response amplitudes with substantially greater amplitude intensity (AI) slopes than medially directed movement. Downward caudal motions in the DV axis produced substantially larger response amplitudes and AI slopes. The results show that the macula lagena does not contribute to the VsEP compound polarization vectors of the sacculus and utricle. The findings suggest further that preferred compound vectors for the utricle depend on the pars externa (i.e. lateral hair cell field) whereas for the saccule they depend on pars interna (i.e. superior hair cell fields). These data provide evidence that maculae saccule and utricle can be selectively evaluated using the linear VsEP.

  8. Analysis of the far-field characteristics of hybridly polarized vector beams from the vectorial structure

    NASA Astrophysics Data System (ADS)

    Li, Jia; Wu, Pinghui; Chang, Liping

    2016-01-01

    Based on the angular spectrum representation of electromagnetic beams, analytical expressions are derived for the TE term, TM term and the whole energy fluxes of a hybridly polarized vector (HPV) beam propagating in the far field. It is shown that both the TE and TM terms of the energy fluxes are strongly dependent of the truncation radius of the circular aperture. By choosing the truncation radius as a certain value, it is found that the far-zone distributions of TE and TM terms exhibit four-petal patterns with surrounding side-lobes displaying oscillating intensities. Interestingly, such phenomenon becomes extremely obvious particularly when the truncation radius is comparable with the wavelength of the propagating beam.

  9. Hydrogen-bonded inclusion compounds with reversed polarity: anionic metal-complexes and cationic organic linkers.

    PubMed

    Prakash, M Jaya; Sevov, Slavi C

    2011-12-19

    Synthesized and structurally characterized is a new series of soft-host frameworks assembled by charge-assisted hydrogen bonds between an anionic metal complex (MC) and cationic organic linkers (OL), specifically [Co(en)(ox)(2)](-) and diprotonated 4,4'-bipyridinium (H(2)bpy) or 1,2-bis(4-pyridinium)ethylene (H(2)bpye). While frameworks built of cationic complexes and anionic organic linkers are already well-known, the seven new compounds described here represent the first series of frameworks with reversed polarity, that is, made of anionic complexes and cationic organic linkers. The compounds have a general formula [OL][MC](2)·n(guest), where the guest molecules 4,4'-biphenol (bp), 4-methoxyphenol (mp), 1,4-dimethoxybenzene (dmb), 1,6-dimethoxynaphtalene (dmn), and 4-nitroanisole (na). Structurally the compounds can be described as pillared-layer frameworks with layers constructed of MC anions and linked together by hydrogen-bonded cationic OL pillars. The guest molecules occupy the galleries between the pillars while their steric, electronic, and π-π and hydrogen-bonding capabilities influence the overall structure of the soft frameworks. PMID:22085246

  10. Hybrid Compounds Strategy in the Synthesis of Oleanolic Acid Skeleton-NSAID Derivatives.

    PubMed

    Pawełczyk, Anna; Olender, Dorota; Sowa-Kasprzak, Katarzyna; Zaprutko, Lucjusz

    2016-01-01

    The current study focuses on the synthesis of several hybrid individuals combining a natural oleanolic acid skeleton and synthetic nonsteroidal anti-inflammatory drug moieties (NSAIDs). It studied structural modifications of the oleanolic acid structure by use of the direct reactivity of hydroxyl or hydroxyimino groups at position C-3 of the triterpenoid skeleton with the carboxylic function of anti-inflammatory drugs leading to new perspective compounds with high potential pharmacological activities. Novel ester- and iminoester-type derivatives of oleanolic unit with the different NSAIDs, such as ibuprofen, aspirin, naproxen, and ketoprofen, were obtained and characterized. Moreover, preliminary research of compounds obtaining structure stability under acidic conditions was examined and the PASS method of prediction of activity spectra for substances was used to estimate the potential biological activity of these compounds. PMID:27077841

  11. Phenolic compounds in berries and flowers of a natural hybrid between bilberry and lingonberry (Vaccinium × intermedium Ruthe).

    PubMed

    Lätti, Anja K; Riihinen, Kaisu R; Jaakola, Laura

    2011-06-01

    Hybridization between species plays an important role in the evolution of secondary metabolites and in the formation of combinations of existing secondary metabolites in plants. We have investigated the content of phenolic compounds in berries and flowers of Vaccinium×intermedium Ruthe, which is a rare natural hybrid between bilberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.). The berries and flowers of the hybrid showed characteristics inherited from both parent species in the distribution and contents of phenolic compounds. Bilberry is known as one of the richest sources of anthocyanins and to have a profile of 15 major forms combining cyanidin, delphinidin, petunidin, peonidin and malvidin with galactose, glucose and arabinose. Lingonberry contains only cyanidin glycosides. Hybrid berries contained all bilberry anthocyanins with pronounced cyanidin content. With regard to proanthocyanidins and flavonol glycosides, the hybrid inherited diverse profiles combining those of both parental species. The distribution of hydroxycinnamic acids was quite uniform in all studied berries. Of the identified compounds, 30 were detected in lingonberry, 46 in bilberry, 53 in hybrid berries and 38 in hybrid flowers. Hence, compared with the parent species, hybrid berries possess a more diverse profile of phenolic compounds and, therefore, can offer interesting material for breeding purposes. PMID:21382629

  12. Design, Synthesis, and Antiplasmodial Activity of Hybrid Compounds Based on (2R,3S)-N-Benzoyl-3-phenylisoserine

    PubMed Central

    2013-01-01

    A series of hybrid compounds based on (2R,3S)-N-benzoyl-3-phenylisoserine, artemisinin, and quinoline moieties was synthesized and tested for in vitro antiplasmodial activity against erythrocytic stages of K1 and W2 strains of Plasmodium falciparum. Two hybrid compounds incorporating (2R,3S)-N-benzoyl-3-phenylisoserine and artemisinin scaffolds were 3- to 4-fold more active than dihydroartemisinin, with nanomolar IC50 values against Plasmodium falciparum K1 strain. PMID:24900723

  13. Selective sensing of volatile organic compounds using novel conducting polymer-metal nanoparticle hybrids

    NASA Astrophysics Data System (ADS)

    Vaddiraju, Sreeram; Gleason, Karen K.

    2010-03-01

    Conducting polymer-metal nanoparticle hybrids, fabricated by assembling metal nanoparticles on top of functionalized conducting polymer film surfaces using conjugated linker molecules, enable the selective sensing of volatile organic compounds (VOCs). In these conducting polymer-metal nanoparticle hybrids, selectivity is achieved by assembling different metals on the same conducting polymer film. This eliminates the need to develop either different polymers chemistries or device configurations for each specific analyte. In the hybrids, chemisorption of the analyte vapor induces charge redistribution in the metal nanoparticles and changes their work function. The conjugated linker molecule causes this change in the work function of the tethered nanoparticles to affect the electronic states in the underlying conducting polymer film. The result is an easily measurable change in the resistance of the hybrid structure. The fabrication of these sensing elements involved the covalent assembly of nickel (Ni) and palladium (Pd) metal nanoparticles on top of poly(3,4-ethylenedioxythiophene-co-thiophene-3-acetic acid), poly(EDOT-co-TAA), films using 4-aminothiophenol linker molecules. The change in resistance of hybrid Pd/poly(EDOT-co-TAA) and Ni/poly(EDOT-co-TAA) hybrid films to acetone and toluene, respectively, is observed to be in proportion to their concentrations. The projected detection limits are 2 and 10 ppm for toluene and acetone, respectively. A negligible response (resistance change) of the Pd/poly(EDOT-co-TAA) films to toluene exposure confirmed its selectivity for detecting acetone. Similarly, lack of response to acetone confirmed the selectivity of the Ni/poly(EDOT-co-TAA) stacks for detecting toluene. It is anticipated that the assembly of other metals such as Ag, Au and Cu on top of poly(EDOT-co-TAA) would provide selectivity for detecting and discriminating other VOCs.

  14. EDITORIAL: New materials with high spin polarization: half-metallic Heusler compounds

    NASA Astrophysics Data System (ADS)

    Felser, Claudia; Hillebrands, Burkard

    2007-03-01

    The development of magnetic Heusler compounds, specifically designed as materials for spintronic applications, has made tremendous progress in the very recent past [1-21]. Heusler compounds can be made as half-metals, showing a high spin polarization of the conduction electrons of up to 100% [1]. These materials are exceptionally well suited for applications in magnetic tunnel junctions acting, for example, as sensors for magnetic fields. The tunnelling magneto-resistance (TMR) effect is the relative change in the electrical resistance upon application of a small magnetic field. Tunnel junctions with a TMR effect of 580% at 4 K were reported by the group of Miyazaki and Ando [1], consisting of two Co2MnSi Heusler electrodes. High Curie temperatures were found in Co2 Heusler compounds with values up to 1120 K in Co2FeSi [2]. The latest results are for a TMR device made from the Co2FeAl0.5Si0.5 Heusler compound and working at room temperature with a TMR effect of 174% [3]. The first significant magneto-resistance effect was discovered in Co2Cr0.6Fe0.4Al (CCFA) in Mainz [4]. With the classical Heusler compound CCFA as one electrode, the record TMR effect at 4 K is 240% [5]. Positive and negative TMR values at room temperature utilizing magnetic tunnel junctions with one Heusler compound electrode render magnetic logic possible [6]. Research efforts exist, in particular, in Japan and in Germany. The status of research as of winter 2005 was compiled in a recent special volume of Journal of Physics D: Applied Physics [7-20]. Since then specific progress has been made on the issues of (i) new advanced Heusler materials, (ii) advanced characterization, and (iii) advanced devices using the new materials. In Germany, the Mainz and Kaiserslautern based Research Unit 559 `New Materials with High Spin Polarization', funded since 2004 by the Deutsche Forschungsgemeinschaft, is a basic science approach to Heusler compounds, and it addresses the first two topics in particular

  15. Hybrid Density Functional Calculations of Redox Potentials of Transition Metal Compounds

    NASA Astrophysics Data System (ADS)

    Armiento, Rickard; Chevrier, Vincent; Ong, Shyue Ping; Ceder, Gerbrand

    2010-03-01

    Prior works have shown that density functional theory (DFT) with the DFT+U method resolves the underestimation of redox potentials calculated by conventional functionals for a number of transition metal compounds relevant for battery applications, including the olivine LixMPO4 (M = Fe, Mn, Co, Ni), layered LixMO2 (M = Co, Ni) and spinel-like LixMn2O4. We show that the redox potentials of these compounds are also well reproduced by the hybrid density functional by Heyd-Scuseria-Ernzerhof (HSE06). Hybrid functionals combine a conventional DFT functional with a part of Hartree-Fock (HF) exchange. While the HF part increases the computational expense by at least one order of magnitude, it provides, in contrast to DFT+U, a correction for the self-interaction error that does not rely on special treatment of the occupancies of the orbital states of ions or species-specific parameters. We compare the accuracy of regular DFT, DFT+U and HSE06 for the redox potentials, lattice constants, and other properties. Examples of electron delocalization problems connected to the self-interaction error in the systems are discussed, and shown to be resolved both by the hybrid functional and DFT+U methods. Comments are made on the possibility to approach the delocalization problem with a semi-local functional.

  16. Improved Hybrid Monte Carlo/n-Moment Transport Equations Model for the Polar Wind

    NASA Astrophysics Data System (ADS)

    Barakat, A. R.; Ji, J.; Schunk, R. W.

    2013-12-01

    In many space plasma problems (e.g. terrestrial polar wind, solar wind, etc.), the plasma gradually evolves from dense collision-dominated into rarified collisionless conditions. For decades, numerous attempts were made in order to address this type of problem using simulations based on one of two approaches. These approaches are: (1) the (fluid-like) Generalized Transport Equations, GTE, and (2) the particle-based Monte Carlo (MC) techniques. In contrast to the computationally intensive MC, the GTE approach can be considerably more efficient but its validity is questionable outside the collision-dominated region depending on the number of transport parameters considered. There have been several attempts to develop hybrid models that combine the strengths of both approaches. In particular, low-order GTE formulations were applied within the collision-dominated region, while an MC simulation was applied within the collisionless region and in the collisional-to-collisionless transition region. However, attention must be paid to assuring the consistency of the two approaches in the region where they are matched. Contrary to all previous studies, our model pays special attention to the ';matching' issue, and hence eliminates the discontinuities/inaccuracies associated with mismatching. As an example, we applied our technique to the Coulomb-Milne problem because of its relevance to the problem of space plasma flow from high- to low-density regions. We will compare the velocity distribution function and its moments (density, flow velocity, temperature, etc.) from the following models: (1) the pure MC model, (2) our hybrid model, and (3) previously published hybrid models. We will also consider a wide range of the test-to-background mass ratio.

  17. Ultrashort broadband polarization beam splitter based on a combined hybrid plasmonic waveguide.

    PubMed

    Chang, Ken-Wei; Huang, Chia-Chien

    2016-01-01

    We propose an ultracompact broadband polarization beam splitter (PBS) based on a combined hybrid plasmonic waveguide (HPW). The proposed PBS separates transverse-electric (TE) and transverse-magnetic (TM) modes using a bent lower HPW with vertical nanoscale gaps and a straight upper HPW with a horizontal nanoscale gap, respectively, without relying on an additional coupling region. This design considerably reduces the length of the PBS to the submicron scale (920 nm, the shortest PBS reported to date) while offering polarization extinction ratios (PERs) of ~19 dB (~18 dB) and insertion losses (ILs) of ~0.6 dB (~0.3 dB) for the TE (TM) mode over an extremely broad band of 400 nm (from λ = 1300 nm to 1700 nm, covering entirely second and third telecom windows). The length of the designed PBS can be reduced further to 620 nm while still offering PERs of 15 dB, realizing a densely photonic integrated circuit. Considering the fabrication tolerance, the designed PBS allows for large geometrical deviations of ± 20 nm while restricting PER variations to within 1 dB, except for those in the nanoscale gaps smaller than 10nm. Additionally, we also address the input and ouput coupling efficiencies of the proposed PBS. PMID:26786972

  18. Ultrashort broadband polarization beam splitter based on a combined hybrid plasmonic waveguide

    PubMed Central

    Chang, Ken-Wei; Huang, Chia-Chien

    2016-01-01

    We propose an ultracompact broadband polarization beam splitter (PBS) based on a combined hybrid plasmonic waveguide (HPW). The proposed PBS separates transverse-electric (TE) and transverse-magnetic (TM) modes using a bent lower HPW with vertical nanoscale gaps and a straight upper HPW with a horizontal nanoscale gap, respectively, without relying on an additional coupling region. This design considerably reduces the length of the PBS to the submicron scale (920 nm, the shortest PBS reported to date) while offering polarization extinction ratios (PERs) of ~19 dB (~18 dB) and insertion losses (ILs) of ~0.6 dB (~0.3 dB) for the TE (TM) mode over an extremely broad band of 400 nm (from λ = 1300 nm to 1700 nm, covering entirely second and third telecom windows). The length of the designed PBS can be reduced further to 620 nm while still offering PERs of 15 dB, realizing a densely photonic integrated circuit. Considering the fabrication tolerance, the designed PBS allows for large geometrical deviations of ±20 nm while restricting PER variations to within 1 dB, except for those in the nanoscale gaps smaller than 10nm. Additionally, we also address the input and ouput coupling efficiencies of the proposed PBS. PMID:26786972

  19. Transmission of photonic quantum polarization entanglement in a nanoscale hybrid plasmonic waveguide.

    PubMed

    Li, Ming; Zou, Chang-Ling; Ren, Xi-Feng; Xiong, Xiao; Cai, Yong-Jing; Guo, Guo-Ping; Tong, Li-Min; Guo, Guang-Can

    2015-04-01

    Photonic quantum technologies have been extensively studied in quantum information science, owing to the high-speed transmission and outstanding low-noise properties of photons. However, applications based on photonic entanglement are restricted due to the diffraction limit. In this work, we demonstrate for the first time the maintaining of quantum polarization entanglement in a nanoscale hybrid plasmonic waveguide composed of a fiber taper and a silver nanowire. The transmitted state throughout the waveguide has a fidelity of 0.932 with the maximally polarization entangled state Φ(+). Furthermore, the Clauser, Horne, Shimony, and Holt (CHSH) inequality test performed, resulting in value of 2.495 ± 0.147 > 2, demonstrates the violation of the hidden variable model. Because the plasmonic waveguide confines the effective mode area to subwavelength scale, it can bridge nanophotonics and quantum optics and may be used as near-field quantum probe in a quantum near-field micro/nanoscope, which can realize high spatial resolution, ultrasensitive, fiber-integrated, and plasmon-enhanced detection. PMID:25775140

  20. Ultrashort broadband polarization beam splitter based on a combined hybrid plasmonic waveguide

    NASA Astrophysics Data System (ADS)

    Chang, Ken-Wei; Huang, Chia-Chien

    2016-01-01

    We propose an ultracompact broadband polarization beam splitter (PBS) based on a combined hybrid plasmonic waveguide (HPW). The proposed PBS separates transverse-electric (TE) and transverse-magnetic (TM) modes using a bent lower HPW with vertical nanoscale gaps and a straight upper HPW with a horizontal nanoscale gap, respectively, without relying on an additional coupling region. This design considerably reduces the length of the PBS to the submicron scale (920 nm, the shortest PBS reported to date) while offering polarization extinction ratios (PERs) of ~19 dB (~18 dB) and insertion losses (ILs) of ~0.6 dB (~0.3 dB) for the TE (TM) mode over an extremely broad band of 400 nm (from λ = 1300 nm to 1700 nm, covering entirely second and third telecom windows). The length of the designed PBS can be reduced further to 620 nm while still offering PERs of 15 dB, realizing a densely photonic integrated circuit. Considering the fabrication tolerance, the designed PBS allows for large geometrical deviations of ±20 nm while restricting PER variations to within 1 dB, except for those in the nanoscale gaps smaller than 10nm. Additionally, we also address the input and ouput coupling efficiencies of the proposed PBS.

  1. Mode-evolution-based polarization rotation and coupling between silicon and hybrid plasmonic waveguides

    PubMed Central

    Kim, Sangsik; Qi, Minghao

    2015-01-01

    Hybrid plasmonic (HP) modes allow strong optical field confinement and simultaneously low propagation loss, offering a potentially compact and efficient platform for on-chip photonic applications. However, their implementation is hampered by the low coupling efficiency between dielectric guided modes and HP modes, caused by mode mismatch and polarization difference. In this work, we present a mode-evolution-based polarization rotation and coupling structure that adiabatically rotates the TE mode in a silicon waveguide and couples it to the HP mode in a strip silicon-dielectric-metal waveguide. Simulation shows that high coupling factors of 92%, 78%, 75%, and 73% are achievable using Ag, Au, Al, and Cu as the metal cap, respectively, at a conversion length of about 5 μm. For an extremely broad wavelength range of 1300–1800 nm, the coupling factor is >64% with a Ag metal cap, and the total back-reflection power, including all the mode reflections and backscattering, is below −40 dB, due to the adiabatic mode transition. Our device does not require high-resolution lithography and is tolerant to fabrication variations and imperfections. These attributes together make our device suitable for optical transport systems spanning all telecommunication bands. PMID:26680655

  2. Ferulic acid-carbazole hybrid compounds: Combination of cholinesterase inhibition, antioxidant and neuroprotection as multifunctional anti-Alzheimer agents.

    PubMed

    Fang, Lei; Chen, Mohao; Liu, Zhikun; Fang, Xubin; Gou, Shaohua; Chen, Li

    2016-02-15

    In order to search for novel multifunctional anti-Alzheimer agents, a series of ferulic acid-carbazole hybrid compounds were designed and synthesized. Ellman's assay revealed that the hybrid compounds showed moderate to potent inhibitory activity against the cholinesterases. Particularly, the AChE inhibition potency of compound 5k (IC50 1.9μM) was even 5-fold higher than that of galantamine. In addition, the target compounds showed pronounced antioxidant ability and neuroprotective property, especially against the ROS-induced toxicity. Notably, the neuroprotective effect of 5k was obviously superior to that of the mixture of ferulic acid and carbazole, indicating the therapeutic effect of the hybrid compound is better than the combination administration of the corresponding mixture. PMID:26795115

  3. The development of high-performance alkali-hybrid polarized He3 targets for electron scattering

    DOE PAGESBeta

    Singh, Jaideep T.; Dolph, Peter A.M.; Tobias, William Al; Averett, Todd D.; Kelleher, Aiden; Mooney, K. E.; Nelyubin, Vladimir V.; Wang, Yunxiao; Zheng, Yuan; Cates, Gordon D.

    2015-05-01

    We present the development of high-performance polarized ³He targets for use in electron scattering experiments that utilize the technique of alkali-hybrid spin-exchange optical pumping. We include data obtained during the characterization of 24 separate target cells, each of which was constructed while preparing for one of four experiments at Jefferson Laboratory in Newport News, Virginia. The results presented here document dramatic improvement in the performance of polarized ³He targets, as well as the target properties and operating parameters that made those improvements possible. Included in our measurements were determinations of the so-called X-factors that quantify a temperature-dependent and as-yet poorly understood spin-relaxation mechanism that limits the maximum achievable ³He polarization to well under 100%. The presence of this spin-relaxation mechanism was clearly evident in our data. We also present results from a simulation of the alkali-hydrid spin-exchange optical pumping process that was developed to provide guidance in the design of these targets. Good agreement with actual performance was obtained by including details such as off-resonant optical pumping. Now benchmarked against experimental data, the simulation is useful for the design of future targets. Included in our results is a measurement of the K- ³He spin-exchange rate coefficientmore » $$k^\\mathrm{K}_\\mathrm{se} = \\left ( 7.46 \\pm 0.62 \\right )\\!\\times\\!10^{-20}\\ \\mathrm{cm^3/s}$$ over the temperature range 503 K to 563 K.« less

  4. Selective Delivery of PEGylated Compounds to Tumor Cells by Anti-PEG Hybrid Antibodies.

    PubMed

    Tung, Hsin-Yi; Su, Yu-Cheng; Chen, Bing-Mae; Burnouf, Pierre-Alain; Huang, Wei-Chiao; Chuang, Kuo-Hsiang; Yan, Yu-Ting; Cheng, Tian-Lu; Roffler, Steve R

    2015-06-01

    Polyethylene glycol (PEG) is attached to many peptides, proteins, liposomes, and nanoparticles to reduce their immunogenicity and improve their pharmacokinetic and therapeutic properties. Here, we describe hybrid antibodies that can selectively deliver PEGylated medicines, imaging agents, or nanomedicines to target cells. Human IgG1 hybrid antibodies αPEG:αHER2 and αPEG:αCD19 were shown by ELISA, FACS, and plasmon resonance to bind to both PEG and HER2 receptors on SK-BR-3 breast adenocarcinoma and BT-474 breast ductal carcinoma cells or CD19 receptors on Ramos and Raji Burkitt's lymphoma cells. In addition, αPEG:αHER2 specifically targeted PEGylated proteins, liposomes, and nanoparticles to SK-BR-3 cells that overexpressed HER2, but not to HER2-negative MCF-7 breast adenocarcinoma cells. Endocytosis of PEGylated nanoparticles into SK-BR-3 cells was induced specifically by the αPEG:αHER2 hybrid antibody, as observed by confocal imaging of the accumulation of Qdots inside SK-BR-3 cells. Treatment of HER2(+) SK-BR-3 and BT-474 cancer cells with αPEG:αHER2 and the clinically used chemotherapeutic agent PEGylated liposomal doxorubicin for 3 hours enhanced the in vitro effectiveness of PEGylated liposomal doxorubicin by over two orders of magnitude. Hybrid anti-PEG antibodies offer a versatile and simple method to deliver PEGylated compounds to cellular locations and can potentially enhance the therapeutic efficacy of PEGylated medicines. PMID:25852063

  5. A wireless hybrid chemical sensor for detection of environmental volatile organic compounds.

    PubMed

    Chen, Cheng; Tsow, Francis; Campbell, Katherine Driggs; Iglesias, Rodrigo; Forzani, Erica; Tao, N J

    2013-05-01

    A hybrid sensor for monitoring volatile organic compounds (VOCs) in air is developed. The device combines two orthogonal sensing principles, selective molecular binding with a microfabricated quartz tuning fork detector and separation of analytes with a column. The tuning fork detector is functionalized with molecular imprinted polymers for selective binding to benzene, toluene, ethylbenzene, and xylenes (BTEX), and the separation column provides further discrimination of the analytes for real world complex sample analysis. The device is wireless, portable, battery-powered, and cell-phone operated, and it allows reliable detection in parts per billion (ppb) by volume-levels of BTEX in the presence of complex interferents. The hybrid device is suitable for occupational, environmental health, and epidemiological applications. PMID:24078793

  6. A wireless hybrid chemical sensor for detection of environmental volatile organic compounds

    PubMed Central

    Chen, Cheng; Tsow, Francis; Campbell, Katherine Driggs; Iglesias, Rodrigo; Forzani, Erica; Tao, N.J.

    2013-01-01

    A hybrid sensor for monitoring volatile organic compounds (VOCs) in air is developed. The device combines two orthogonal sensing principles, selective molecular binding with a microfabricated quartz tuning fork detector and separation of analytes with a column. The tuning fork detector is functionalized with molecular imprinted polymers for selective binding to benzene, toluene, ethylbenzene, and xylenes (BTEX), and the separation column provides further discrimination of the analytes for real world complex sample analysis. The device is wireless, portable, battery-powered, and cell-phone operated, and it allows reliable detection in parts per billion (ppb) by volume-levels of BTEX in the presence of complex interferents. The hybrid device is suitable for occupational, environmental health, and epidemiological applications. PMID:24078793

  7. Highly Polar Organic Compounds in Summer Cloud Water from Whiteface Mountain, NY

    NASA Astrophysics Data System (ADS)

    Sagona, J. A.; Dukett, J. E.; Mazurek, M.

    2010-12-01

    Highly polar organic compounds (HPOC) containing multiple oxygen atoms are of interest due to the aerosol direct and indirect effects and uncertainty they may contribute to climate forcing. Atmospheric HPOC exist as particulate or dissolved chemical species depending on relative humidity. HPOC solid mixtures are thought to scatter and absorb light due to particle size and color (white to yellow). Understanding the chemical composition of HPOC in cloud water (CW) is important for modeling and predicting the direct and indirect influences of this organic aerosol component on the climate system. In this initial study we present a detailed molecular examination of 10 CW samples. CW samples were collected in September 2009 using an automated CW collector at Whiteface Mountain (elevation 1483 m) in the Adirondack Mountains in upstate NY. We performed QA/QC experiments for the CW samples and analyzed the HPOC mixtures by ultratrace gas chromatography/mass spectrometry. Diacids such as oxalic acid and succinic acid were major components of the CW HPOC with concentrations on the order of 15 ng/mL. Substituted diacids, monoacids, and sugars also were present. We discuss the possible sources of these compounds in light of back-trajectory analysis.

  8. Synthesis and biological screening by novel hybrid fluorocarbon hydrocarbon compounds for use as artificial blood substitutes

    NASA Technical Reports Server (NTRS)

    Moacanin, J.; Scherer, K.; Toronto, A.; Lawson, D.; Terranova, T.; Yavrouian, A.; Astle, L.; Harvey, S.; Kaaelble, D. H.

    1979-01-01

    A series of hybrid fluorochemicals of general structure R(1)R(2)R(3)CR(4) was prepared where the R(i)'s (i=1,2,3) is a saturated fluoroalkyl group of formula C sub N F sub 2n+1, and R(4) is an alkyl group C sub n H sub 2n+1 or a related moiety containing amino, ether, or ester functions but no CF bonds. Compounds of this class containing approximately eight to twenty carbons total have physical properties suitable for use as the oxygen carrying phase of fluorochemical emulsion artificial blood. The chemical synthesis, and physical and biological testing of pure single isomers of the proposed artificial blood candidate compounds are included. Significant results are given.

  9. EDITORIAL: New materials with high spin polarization: half-metallic Heusler compounds

    NASA Astrophysics Data System (ADS)

    Felser, Claudia; Hillebrands, Burkard

    2007-03-01

    The development of magnetic Heusler compounds, specifically designed as materials for spintronic applications, has made tremendous progress in the very recent past [1-21]. Heusler compounds can be made as half-metals, showing a high spin polarization of the conduction electrons of up to 100% [1]. These materials are exceptionally well suited for applications in magnetic tunnel junctions acting, for example, as sensors for magnetic fields. The tunnelling magneto-resistance (TMR) effect is the relative change in the electrical resistance upon application of a small magnetic field. Tunnel junctions with a TMR effect of 580% at 4 K were reported by the group of Miyazaki and Ando [1], consisting of two Co2MnSi Heusler electrodes. High Curie temperatures were found in Co2 Heusler compounds with values up to 1120 K in Co2FeSi [2]. The latest results are for a TMR device made from the Co2FeAl0.5Si0.5 Heusler compound and working at room temperature with a TMR effect of 174% [3]. The first significant magneto-resistance effect was discovered in Co2Cr0.6Fe0.4Al (CCFA) in Mainz [4]. With the classical Heusler compound CCFA as one electrode, the record TMR effect at 4 K is 240% [5]. Positive and negative TMR values at room temperature utilizing magnetic tunnel junctions with one Heusler compound electrode render magnetic logic possible [6]. Research efforts exist, in particular, in Japan and in Germany. The status of research as of winter 2005 was compiled in a recent special volume of Journal of Physics D: Applied Physics [7-20]. Since then specific progress has been made on the issues of (i) new advanced Heusler materials, (ii) advanced characterization, and (iii) advanced devices using the new materials. In Germany, the Mainz and Kaiserslautern based Research Unit 559 `New Materials with High Spin Polarization', funded since 2004 by the Deutsche Forschungsgemeinschaft, is a basic science approach to Heusler compounds, and it addresses the first two topics in particular

  10. Core-shell nanostructured hybrid composites for volatile organic compound detection

    PubMed Central

    Tung, Tran Thanh; Losic, Dusan; Park, Seung Jun; Feller, Jean-Francois; Kim, TaeYoung

    2015-01-01

    We report a high-performance chemiresistive sensor for detection of volatile organic compound (VOC) vapors based on core-shell hybridized nanostructures of Fe3O4 magnetic nanoparticles (MNPs) and poly(3,4-ethylenedioxythiophene) (PEDOT)-conducting polymers. The MNPs were prepared using microwave-assisted synthesis in the presence of polymerized ionic liquids (PILs), which were used as a linker to couple the MNP and PEDOT. The resulting PEDOT–PIL-modified Fe3O4 hybrids were then explored as a sensing channel material for a chemiresistive sensor to detect VOC vapors. The PEDOT–PIL-modified Fe3O4 sensor exhibited a tunable response, with high sensitivity (down to a concentration of 1 ppm) and low noise level, to VOCs; these VOCs include acetone vapor, which is present in the exhaled breath of potential lung cancer patients. The present sensor, based on the hybrid nanostructured sensing materials, exhibited a 38.8% higher sensitivity and an 11% lower noise level than its PEDOT–PIL-only counterpart. This approach of embedding MNPs in conducting polymers could lead to the development of new electronic noses, which have significant potential for the use in the early diagnosis of lung cancer via the detection of VOC biomarkers. PMID:26357471

  11. Core-shell nanostructured hybrid composites for volatile organic compound detection.

    PubMed

    Tung, Tran Thanh; Losic, Dusan; Park, Seung Jun; Feller, Jean-Francois; Kim, TaeYoung

    2015-01-01

    We report a high-performance chemiresistive sensor for detection of volatile organic compound (VOC) vapors based on core-shell hybridized nanostructures of Fe3O4 magnetic nanoparticles (MNPs) and poly(3,4-ethylenedioxythiophene) (PEDOT)-conducting polymers. The MNPs were prepared using microwave-assisted synthesis in the presence of polymerized ionic liquids (PILs), which were used as a linker to couple the MNP and PEDOT. The resulting PEDOT-PIL-modified Fe3O4 hybrids were then explored as a sensing channel material for a chemiresistive sensor to detect VOC vapors. The PEDOT-PIL-modified Fe3O4 sensor exhibited a tunable response, with high sensitivity (down to a concentration of 1 ppm) and low noise level, to VOCs; these VOCs include acetone vapor, which is present in the exhaled breath of potential lung cancer patients. The present sensor, based on the hybrid nanostructured sensing materials, exhibited a 38.8% higher sensitivity and an 11% lower noise level than its PEDOT-PIL-only counterpart. This approach of embedding MNPs in conducting polymers could lead to the development of new electronic noses, which have significant potential for the use in the early diagnosis of lung cancer via the detection of VOC biomarkers. PMID:26357471

  12. Synthesis and fluorescence properties of six fluorescein-nitroxide radical hybrid-compounds.

    PubMed

    Sato, Shingo; Endo, Susumu; Kurokawa, Yusuke; Yamaguchi, Masaki; Nagai, Akio; Ito, Tomohiro; Ogata, Tateaki

    2016-12-01

    Six fluorescein-nitroxide radical hybrid-compounds (2ab, 3ab, 4, and 5) were synthesized by the condensation of 5- or 6-carboxy-fluorescein and 4-amino-TEMPO (2ab), 5- or 6-aminofluorescein and 4-carboxy-TEMPO (3ab), and fluorescein and 4-carboxy-TEMPO (4), or by reaction of the 3-hydroxyl group of fluorescein with DPROXYL-3-ylmethyl methanesulfonate (5). Fluorescence intensities (around 520nm) after reduction of the radical increased to 1.43-, 1.38-, and 1.61-folds for 2a, 2b and 3b respectively; 3a alone exhibited a decrease in intensity on reduction. Since 4 was readily solvolyzed in PBS or even methanol to afford fluorescein and 4-carboxy-TEMPO, its fluorescence change could not be measured. Hybrid compound 5 containing an ether-linkage between the fluorescein phenol and 3-hydroxymethyl-DPROXYL hydroxyl centers, was stable and on reduction, showed a maximum increase (3.21-fold) in relative fluorescence intensity in PBS (pH5.0), despite its remarkably low absolute fluorescence intensity. PMID:27337053

  13. Hybrid cable television and orthogonal-frequency-division-multiplexing transport system basing on single wavelength polarization and amplitude remodulation schemes.

    PubMed

    Chang, Ching-Hung; Liu, Wei-Chen; Peng, Peng-Chun; Lu, Hai-Han; Wu, Po-Yi; Wang, Jyun-Bo

    2011-05-01

    A hybrid community antenna television (CATV) and orthogonal-frequency-division-multiplexing (OFDM) transport system is proposed and experimentally demonstrated to transmit multiple CATV channels and bi-directional radio frequency signals on a single optical carrier. By polarization remodulating an optical CATV signal with downstream OFDM signals and then amplitude remodulating upstream OFDM signals with the hybrid CATV/OFDM signals, this architecture can efficiently utilize only one optical carrier to support optical analog/digital CATV transmission and bi-directional wireless broadband services for each client. Good experimental results prove that this architecture provides a proper wavelength utilization scheme for future multiwavelength optical transport systems. PMID:21540979

  14. Hybrid density functional calculations of redox potentials and formation energies of transition metal compounds

    NASA Astrophysics Data System (ADS)

    Chevrier, V. L.; Ong, S. P.; Armiento, R.; Chan, M. K. Y.; Ceder, G.

    2010-08-01

    We compare the accuracy of conventional semilocal density functional theory (DFT), the DFT+U method, and the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional for structural parameters, redox reaction energies, and formation energies of transition metal compounds. Conventional DFT functionals significantly underestimate redox potentials for these compounds. Zhou [Phys. Rev. B 70, 235121 (2004)]10.1103/PhysRevB.70.235121 addressed this issue with DFT+U and a linear-response scheme for calculating U values. We show that the Li intercalation potentials of prominent Li-ion intercalation battery materials, such as the layered LixMO2 ( M=Co and Ni), LixTiS2 ; olivine LixMPO4 ( M=Mn , Fe, Co, and Ni); and spinel-like LixMn2O4 , LixTi2O4 , are also well reproduced by HSE06, due to the self-interaction error correction from the partial inclusion of Hartree-Fock exchange. For formation energies, HSE06 performs well for transition metal compounds, which typically are not well reproduced by conventional DFT functionals but does not significantly improve the results of nontransition metal oxides. Hence, we find that hybrid functionals provide a good alternative to DFT+U for transition metal applications when the large extra computational effort is compensated by the benefits of (i) avoiding species-specific adjustable parameters and (ii) a more universal treatment of the self-interaction error that is not exclusive to specific atomic orbital projections on selected ions.

  15. Characterization of polar organic compounds and source analysis of fine organic aerosols in Hong Kong

    NASA Astrophysics Data System (ADS)

    Li, Yunchun

    Organic aerosols, as an important fraction of airborne particulate mass, significantly affect the environment, climate, and human health. Compared with inorganic species, characterization of individual organic compounds is much less complete and comprehensive because they number in thousands or more and are diverse in chemical structures. The source contributions of organic aerosols are far from being well understood because they can be emitted from a variety of sources as well as formed from photochemical reactions of numerous precursors. This thesis work aims to improve the characterization of polar organic compounds and source apportionment analysis of fine organic carbon (OC) in Hong Kong, which consists of two parts: (1) An improved analytical method to determine monocarboxylic acids, dicarboxylic acids, ketocarboxylic acids, and dicarbonyls collected on filter substrates has been established. These oxygenated compounds were determined as their butyl ester or butyl acetal derivatives using gas chromatography-mass spectrometry. The new method made improvements over the original Kawamura method by eliminating the water extraction and evaporation steps. Aerosol materials were directly mixed with the BF 3/BuOH derivatization agent and the extracting solvent hexane. This modification improves recoveries for both the more volatile and the less water-soluble compounds. This improved method was applied to study the abundances and sources of these oxygenated compounds in PM2.5 aerosol samples collected in Hong Kong under different synoptic conditions during 2003-2005. These compounds account for on average 5.2% of OC (range: 1.4%-13.6%) on a carbon basis. Oxalic acid was the most abundant species. Six C2 and C3 oxygenated compounds, namely oxalic, malonic, glyoxylic, pyruvic acids, glyoxal, and methylglyoxal, dominated this suite of oxygenated compounds. More efforts are therefore suggested to focus on these small compounds in understanding the role of oxygenated

  16. Intermodal and cross-polarization four-wave mixing in large-core hybrid photonic crystal fibers.

    PubMed

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2015-03-01

    Degenerate four-wave mixing is considered in large mode area hybrid photonic crystal fibers, combining photonic bandgap guidance and index guidance. Co- and orthogonally polarized pump, signal and idler fields are considered numerically by calculating the parametric gain and experimentally by spontaneous degenerate four-wave mixing. Intermodal and birefringence assisted intramodal phase matching is observed. Good agreement between calculations and experimental observations is obtained. Intermodal four-wave mixing is achieved experimentally with a conversion efficiency of 17%. PMID:25836821

  17. SEMI-VOLATILE ORGANIC ACIDS AND OTHER POLAR COMPOUNDS COLLECTED IN NEW YORK CITY IN RESPONSE TO THE EVENTS OF 9/11

    EPA Science Inventory

    Concentrations of over 25 polar semi-volatile and non-volatile organic compounds were measured in Lower Manhattan, New York using a high capacity Integrated Organic Gas and Particle sampler, after the initial destruction of the World Trade Center. The polar organic compounds in...

  18. Determination of phenolic compounds in air by using cyclodextrin-silica hybrid microporous composite samplers.

    PubMed

    Mauri-Aucejo, Adela R; Ponce-Català, Patricia; Belenguer-Sapiña, Carolina; Amorós, Pedro

    2015-03-01

    An analytical method for the determination of phenolic compounds in air samples based on the use of cyclodextrin-silica hybrid microporous composite samplers is proposed. The method allows the determination of phenol, guaiacol, cresol isomers, eugenol, 4-ethylphenol and 4-ethylguaiacol in workplaces according to the Norm UNE-EN 1076:2009 for active sampling. Therefore, the proposed method offers an alternative for the assessment of the occupational exposure to phenol and cresol isomers. The detection limits of the proposed method are lower than those for the NIOSH Method 2546. Storage time of samples almost reaches 44 days. Recovery values for phenol, guaiacol, o-cresol, m-cresol, p-cresol, 4-ethylguaiacol, eugenol and 4-ethylphenol are 109%, 99%, 102%, 94%, 94%, 91%, 95% and 102%, respectively with a coefficient of variation below 6%. The method has been applied to the assessment of exposure in different areas of a farm and regarding the quantification of these compounds in the vapors generated by burning incense sticks and an essential oil marketed as air fresheners. The acquired results are comparable with those provided from a reference method for a 95% of confidence level. The possible use of these samplers for the sampling of other toxic compounds such as phthalates is evaluated by qualitative analysis of extracts from incense sticks and essential oil samples. PMID:25618708

  19. Selective separation and purification of highly polar basic compounds using a silica-based strong cation exchange stationary phase.

    PubMed

    Long, Zhen; Guo, Zhimou; Xue, Xingya; Zhang, Xiuli; Nordahl, Lilly; Liang, Xinmiao

    2013-12-01

    Compared to moderately and weakly hydrophilic bases, highly polar basic compounds are even more difficult to separate due to their poor retention in reversed phase (RP) mode. This study described the successful applications of a strong cation exchange (SCX) stationary phase to achieve symmetric peak shape, adequate retention and selectivity in the separation of very polar basic compounds. Salt and acetonitrile concentrations were adjusted to optimize the separation. Good correlations (R(2)=0.998-1.000) between the logarithm of the retention factor and the logarithm of salt or acetonitrile concentration were obtained. Gradients generated by changing salt or acetonitrile concentration were compared for the analysis of different highly polar bases. Although all of the analytes were eluted more quickly with an acetonitrile gradient, the effect of the gradients tested on peak width and peak shape varied with respect to analyte. In addition, the effects of different types of cation and anion additives were also investigated. After separation parameters were acquired, the SCX-based method was utilized to analyze highly hydrophilic alkaloids from Scopolia tangutica Maxim with high separation efficiency (plate numbers>32,000 m(-1)). Concurrently, one very polar alkaloid fraction was purified with symmetric peak shape using the current method. Our results suggest that SCX stationary phase can be used as an alternative to RP stationary phase in the analysis and purification of highly hydrophilic basic compounds. PMID:24267097

  20. Simultaneous detection of nonpolar and polar compounds by heat-assisted laser ablation electrospray ionization mass spectrometry.

    PubMed

    Vaikkinen, Anu; Shrestha, Bindesh; Nazarian, Javad; Kostiainen, Risto; Vertes, Akos; Kauppila, Tiina J

    2013-01-01

    A heat-assisted laser ablation electrospray ionization (HA-LAESI) method for the simultaneous mass spectrometric analysis of nonpolar and polar analytes was developed. The sample was introduced using mid-infrared laser ablation of a water-rich target. The ablated analytes were ionized with an electrospray plume, which was intercepted by a heated nitrogen gas jet that enhanced the ionization of analytes of low polarity. The feasibility of HA-LAESI was tested by analyzing, e.g., naphtho[2,3-a]pyrene, cholesterol, tricaprylin, 1,1',2,2'-tetramyristoyl cardiolipin, bradykinin fragment 1-8, and 1-palmitoyl-2-oleoyl-sn-glycerol. HA-LAESI was found better suited for low polarity compounds than conventional LAESI, whereas polar compounds were observed with both techniques. The sensitivity of HA-LAESI for the polar bradykinin fragment 1-8 was slightly lower than observed for LAESI. HA-LAESI showed a linear response for 500 nM to 1.0 mM solutions (n = 11) of verapamil with R(2) = 0.988. HA-LAESI was applied for the direct analysis of tissue samples, e.g., avocado (Persea americana) mesocarp and mouse brain tissue sections. Spectra of the avocado showed abundant triglyceride ion peaks, and the results for the mouse brain sections showed cholesterol as the main species. Conventional LAESI shows significantly lower ionization efficiency for these neutral lipids. HA-LAESI can be applied to the analysis of nonpolar and polar analytes, and it extends the capabilities of conventional LAESI to nonpolar and neutral compounds. PMID:23199051

  1. Generation of azimuthally polarized beams in fast axial flow CO2 laser with hybrid circular subwavelength grating mirror.

    PubMed

    Zhao, Jiang; Li, Bo; Zhao, Heng; Wang, Wenjin; Hu, Yi; Liu, Sisi; Wang, Youqing

    2014-06-10

    A hybrid circular subwavelength grating mirror is proposed and fabricated as a rear mirror in a fast axial flow CO2 laser system to generate azimuthally polarized beams (APBs). This grating mirror, with particular gold-covered ridges and nanopillar-stuffed grooves, performs wideband TE wave reflectivity and high polarization selectivity. It shows that the polarization selectivity mechanism lies in the gold ridge's high reflectivity to the TE wave and the lower TM wave reflectivity, which are the result of the mode leaking into substrate through the dielectric-like nanopillar layer. Finally, a high-quality 550 W APB is obtained in subsequent experiments, which provides potential applications in drilling and welding. PMID:24921136

  2. Analysis of highly polar compounds in groundwater samples from ammunition waste sites. Part I-Characterization of the pollutant spectrum.

    PubMed

    Preiss, Alfred; Elend, Manfred; Gerling, Susanne; Tränckner, Simone

    2005-09-01

    Five groundwater samples from the former ammunition production site at Elsnig, Germany, were analyzed for highly polar components by LC-NMR and LC-MS. A variety of unknown pollutants could be identified. Possibilities and limitations of the combined use of LC-NMR and LC-MS techniques for on-line identification are discussed. Further unknown components were identified through isolation by HPLC cuts and off-line NMR and MS investigations. Most of the polar compounds in the investigated samples could also be quantified. PMID:16049958

  3. Multifunctional soft hybrid bio-platforms based on nano-silver and natural compounds.

    PubMed

    Barbinta-Patrascu, M E; Badea, N; Pirvu, C; Bacalum, M; Ungureanu, C; Nadejde, P L; Ion, C; Rau, I

    2016-12-01

    Novel nanohybrids consisting of nano-Ag, chitosan, lipids and phyto-compounds (chlorophyll a and curcumin) have been achieved through a simple bottom-up strategy, resulting in stable (ZP=-30.9mV) and spherical-shaped nano-entities with size <200nm (estimated by AFM analysis and DLS measurements). The formation of these biohybrids was monitored by absorption and emission spectroscopy, exploiting the spectral fingerprint of chlorophyll a. The bio-performances of these hybrid materials such as: high antioxidant activity (96.63%), strong biocidal properties against Escherichia coli ATCC 8738 (exhibiting an inhibition zone diameter of 32mm), hemocompatibility, in vitro cytotoxicity against HT-29 cancer cells and no toxicity to normal cells (in the biohybrid concentration range of 5.7-17%), make them promising candidates in bio-applications (antimicrobial and antioxidant coating, cancer treatment). PMID:27612787

  4. Polyaniline nanoparticle-carbon nanotube hybrid network vapour sensors with switchable chemo-electrical polarity

    NASA Astrophysics Data System (ADS)

    Lu, Jianbo; Park, Bong Jun; Kumar, Bijandra; Castro, Mickaël; Choi, Hyoung Jin; Feller, Jean-François

    2010-06-01

    Chemo-resistive sensors were prepared from monodisperse poly(aniline) nanoparticles (PaniNP) synthesized via oxidative dispersion polymerization. Poly(styrene sulfonic acid) (PSSA) was used as the stabilizer and dopant agent. PaniNP transducers were assembled by spraying layer by layer a solution containing different concentrations of PaniNP and multi-wall carbon nanotubes (MWNT) onto interdigitated electrodes. This process led to stable sensors with reproducible responses upon chemical cycling. Chemo-electrical properties of these sensors have been investigated in sequential flows of pure nitrogen and nitrogen saturated with a set of volatile organic compounds (VOC). Interestingly the sensing mode of PaniNP transducers (the NVC or PVC effect) can be switched simply by increasing PaniNP content or by the addition of only 0.5% of MWNT to reach a resistance lower than 150 Ω. Due to their original conducting architecture well imaged by atomic force microscopy (AFM), i.e. a double percolated conductive network, PaniNP-MWNT hybrids present both higher sensitivity and selectivity than other formulations, demonstrating a positive synergy. Mechanisms are proposed to describe the original chemo-electrical behaviours of PaniNP-based sensors and explain the origin of their selectivity and sensing principle. These features make them attractive to be integrated in e-noses.

  5. Potential of genetically engineered hybrid poplar for pyrolytic production of bio-based phenolic compounds.

    PubMed

    Toraman, Hilal E; Vanholme, Ruben; Borén, Eleonora; Vanwonterghem, Yumi; Djokic, Marko R; Yildiz, Guray; Ronsse, Frederik; Prins, Wolter; Boerjan, Wout; Van Geem, Kevin M; Marin, Guy B

    2016-05-01

    Wild-type and two genetically engineered hybrid poplar lines were pyrolyzed in a micro-pyrolysis (Py-GC/MS) and a bench scale setup for fast and intermediate pyrolysis studies. Principal component analysis showed that the pyrolysis vapors obtained by micro-pyrolysis from wood of caffeic acid O-methyltransferase (COMT) and caffeoyl-CoA O-methyltransferase (CCoAOMT) down-regulated poplar trees differed significantly from the pyrolysis vapors obtained from non-transgenic control trees. Both fast micro-pyrolysis and intermediate pyrolysis of transgenic hybrid poplars showed that down-regulation of COMT can enhance the relative yield of guaiacyl lignin-derived products, while the relative yield of syringyl lignin-derived products was up to a factor 3 lower. This study indicates that lignin engineering via genetic modifications of genes involved in the phenylpropanoid and monolignol biosynthetic pathways can help to steer the pyrolytic production of guaiacyl and syringyl lignin-derived phenolic compounds such as guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-vinylguaiacol, syringol, 4-vinylsyringol, and syringaldehyde present in the bio-oil. PMID:26890798

  6. Photoreceptors in the crayfish compound eye: electrical interactions between cells as related to polarized-light sensitivity

    PubMed Central

    Muller, Kenneth J.

    1973-01-01

    1. The sensitivity to plane-polarized light and the electrical interactions of photoreceptors were examined with intracellular and extracellular micro-electrodes in excised compound eyes of the crayfish. 2. There are two types of photoreceptor: each photoreceptor cell responds best to polarized light when the electric-vector of the light is oriented in one of two orthogonal directions. Seven cells, representing each type, are grouped together to form ommatidia. 3. In each ommatidium, cells that are sensitive to the same orientation of the electric-vector of polarized light are coupled electrically. Cells having orthogonal polarized-light sensitivities are not coupled. 4. Nearly all cells studied were sensitive to orange light. A few cells of both types were found that were sensitive to blue light. Blue-sensitive cells were not coupled to orange-sensitive cells. 5. The photocurrents of both cell types produce negative extracellular potentials which can be greater than 10 mV when measured near the photoreceptive membranes within ommatidia. Evidence suggests that the extracellular potentials produced by one type of cell can effectively reduce the receptor potentials recorded in the other cell type. It is proposed that such a mutual non-synaptic interaction can make a cell more sensitive to the orientation of polarized-light than would be predicted from the cell's differential absorption of polarized light (i.e. its dichroic ratio). ImagesAB PMID:4759681

  7. Design and fabrication of polarization-insensitive hybrid solgel arrayed waveguide gratings.

    PubMed

    Park, Soon-Ryong; Jeong, Jaewan; O, Beom-Hoan; Lee, Seung-Gol; Lee, El-Hang

    2003-03-15

    We report on the successful design and fabrication of a polarization-insensitive arrayed waveguide grating (AWG), using solgel-derived silica glass films formed on fused-silica substrates. By controlling the waveguide width and making the propagation constants of the polarizations equal, we have found it possible to fabricate polarization-insensitive solgel-based AWGs. Polarization-insensitive design improves the cross talk by approximately 10 dB in the dynamic range. PMID:12659253

  8. Rapid screening of polar compounds in Brazilian propolis by high-temperature high-resolution gas chromatography-mass spectrometry.

    PubMed

    Pereira, A S; Norsell, M; Cardoso, J N; Aquino Neto, F R; Ramos, M F

    2000-11-01

    Methanol extracts of propolis from six different places, five in Rio de Janeiro state and one in São Paulo state, both in the Southeast of Brazil, were investigated using high-temperature high-resolution gas chromatography (HT-HRGC) and HT-HRGC-mass spectometry. The main purpose of the study was to establish the applicability of HT-HRGC as an analytical method for systematic studies of polar propolis fractions. Several compounds, including carbohydrates, phenolic acid derivatives, and high molecular weight compounds (e.g., wax esters of long chain fatty alcohols) could be readily characterized in the crude extracts by HT-HRGC-MS. HT-HRGC and HT-HRGC-MS were shown to be quick and informative tools for rapid analysis of crude polar extracts without cleanup. PMID:11087464

  9. Copper(I) Metal-Organic Framework: Visual Sensor for Detecting Small Polar Aliphatic Volatile Organic Compounds.

    PubMed

    Yu, Yang; Ma, Jian-Ping; Zhao, Chao-Wei; Yang, Jing; Zhang, Xiao-Meng; Liu, Qi-Kui; Dong, Yu-Bin

    2015-12-21

    A porous Cu(I)-MOF [H2O⊂Cu2(L)2I2; L = 1-benzimidazolyl-3,5-bis(4-pyridyl)benzene], which can be a visual and luminescent sensor for detecting small polar aliphatic volatile organic compounds (VOCs), such as alcohols, ketones, and halocarbons, is reported. The naked-eye and luminescent detection limitations for these VOCs are 5 and 1 ppm, respectively. PMID:26645672

  10. Spin exchange optical pumping based polarized {sup 3}He filling station for the Hybrid Spectrometer at the Spallation Neutron Source

    SciTech Connect

    Jiang, C. Y.; Tong, X.; Brown, D. R.; Culbertson, H.; Kadron, B.; Robertson, J. L.; Graves-Brook, M. K.; Hagen, M. E.; Lee, W. T.; Winn, B.

    2013-06-15

    The Hybrid Spectrometer (HYSPEC) is a new direct geometry spectrometer at the Spallation Neutron Source at the Oak Ridge National Laboratory. This instrument is equipped with polarization analysis capability with 60 Degree-Sign horizontal and 15 Degree-Sign vertical detector coverages. In order to provide wide angle polarization analysis for this instrument, we have designed and built a novel polarized {sup 3}He filling station based on the spin exchange optical pumping method. It is designed to supply polarized {sup 3}He gas to HYSPEC as a neutron polarization analyzer. In addition, the station can optimize the {sup 3}He pressure with respect to the scattered neutron energies. The depolarized {sup 3}He gas in the analyzer can be transferred back to the station to be repolarized. We have constructed the prototype filling station. Preliminary tests have been carried out demonstrating the feasibility of the filling station. Here, we report on the design, construction, and the preliminary results of the prototype filling station.

  11. Effect-directed analysis to explore the polar bear exposome: identification of thyroid hormone disrupting compounds in plasma.

    PubMed

    Simon, Eszter; van Velzen, Martin; Brandsma, Sicco H; Lie, Elisabeth; Løken, Katharina; de Boer, Jacob; Bytingsvik, Jenny; Jenssen, Bjørn M; Aars, Jon; Hamers, Timo; Lamoree, Marja H

    2013-08-01

    Compounds with transthyretin (TTR)-binding potency in the blood plasma of polar bear cubs were identified with effect-directed analysis (EDA). This approach contributes to the understanding of the thyroid disrupting exposome of polar bears. The selection of these samples for in-depth EDA was based on the difference between the observed TTR-binding potency on the one hand and the calculated potency (based on known concentrations of TTR-binding compounds and their relative potencies) on the other. A library-based identification was applied to the liquid chromatography-time-of-flight-mass spectrometry (LC-ToF-MS) data by screening for matches between compound lists and the LC-ToF-MS data regarding accurate mass and isotope pattern. Then, isotope cluster analysis (ICA) was applied to the LC-ToF-MS data allowing specific screening for halogen isotope patterns. The presence of linear and branched nonylphenol (NP) was observed for the first time in polar bears. Furthermore, the presence of one di- and two monohydroxylated octachlorinated biphenyls (octaCBs) was revealed in the extracts. Linear and branched NP, 4'-OH-CB201 and 4,4'-OH-CB202 could be successfully confirmed with respect to their retention time in the analytical system. In addition, branched NP, mono- and dihydroxylated-octaCBs showed TTR-binding potencies and could explain another 32 ± 2% of the total measured activities in the extracts. PMID:23763488

  12. Molecularly imprinted polymers for the pre-concentration of polar organic micropollutants for compound-specific isotope analysis

    NASA Astrophysics Data System (ADS)

    Bakkour, Rani; Hofstetter, Thomas B.

    2014-05-01

    Compound-specific isotope analysis (CSIA) is a promising tool for assessing transformations of polar organic micropollutants such as pesticides, pharmaceuticals and consumer chemicals in aquatic systems. There are, however, two major challenges: (1) Polar organic micropollutants occur at very low levels and, as a consequence, large amounts of water are required to achieve analyte enrichment with factors of 50'000 and more, inevitably leading to large interferences from the aqueous matrix. (2) The polarity of these micropollutants impedes the use of typical non-polar sorbates for solid-phase enrichment. In view of these challenges, the use of molecularly imprinted polymers (MIP) is a promising approach to produce tailor-made materials for highly selective enrichment of polar organic micropollutants with reduced matrix interferences. In this work, we explore the use of MIP to selectively enrich benzotriazoles, an important class of polar aquatic micropollutants. Polymers were synthesized in the presence of 5,6-dimethyl-1H-benzotriazole as a template, which leaves cavities in the polymer matrix with a very high affinity to the template and closely related structures including our main target analyte, 1H-benzotrizole. After extraction of the template, specific recognition of substituted benzotriazoles is expected by the synthesized MIPs. As the MIP has no specific affinity to the matrix, there is also expected to be negligible enrichment of the matrix. Retention factors of the MIP are compared for different synthetic procedures and to non-imprinted polymers where no specific intermolecular interactions with benzotriazoles are expected. Optimum performance of the MIP is demonstrated in this study in terms of the selectivity of enrichment, recoveries of analytes and the goodness of carbon and nitrogen isotope ratios measured by gas chromatography isotopic ratio mass spectrometry (GC/IRMS). This approach will enable us to enrich large amounts of aqueous samples while

  13. Novel R-roscovitine NO-donor hybrid compounds as potential pro-resolution of inflammation agents

    PubMed Central

    Montanaro, Gabriele; Bertinaria, Massimo; Rolando, Barbara; Fruttero, Roberta; Lucas, Christopher D.; Dorward, David A.; Rossi, Adriano G.; Megson, Ian L.; Gasco, Alberto

    2013-01-01

    Neutrophils play a pivotal role in the pathophysiology of multiple human inflammatory diseases. Novel pharmacological strategies which drive neutrophils to undergo programmed cell death (apoptosis) have been shown to facilitate the resolution of inflammation. Both the cyclin-dependent kinase inhibitor (CDKi) R-roscovitine and nitric oxide (NO) have been shown to enhance apoptosis of neutrophils and possess pro-resolution of inflammation properties. In order to search for new multi-target pro-resolution derivatives, here we describe the design, synthesis and investigation of the biological potential of a small series of hybrid compounds obtained by conjugating R-roscovitine with two different NO-donor moieties (compounds 2, 9a, 9c). The synthesized compounds were tested as potential pro-resolution agents, with their ability to promote human neutrophil apoptosis evaluated. Both compound 9a and 9c showed an increased pro-apoptotic activity when compared with either R-roscovitine or structurally related compounds devoid of the ability to release NO (des-NO analogues). Inhibition of either NO-synthase or soluble guanylate cyclase did not affect the induction of apoptosis by the R-roscovitine derivatives, similar to that reported for other classes of NO-donors. In contrast the NO scavenger PTIO prevented the enhanced apoptosis seen with compound 9a over R-roscovitine. These data show that novel compounds such as CDKi–NO-donor hybrids may have additive pro-resolution of inflammation effects. PMID:23394865

  14. Potential influence of iodine-containing compounds on the chemistry of the troposphere in the polar spring. I. Ozone depletion

    SciTech Connect

    Calvert, Jack G; Lindberg, Steven Eric

    2004-05-01

    Iodine in the atmosphere, identified largely by the presence of IO, is a ubiquitous component of the troposphere in coastal and oceanic areas. The role, if any, that iodine chemistry plays in the polar ozone depletion episodes is not known. These events are rationalized today largely in terms of Br2- and BrCl-initiated reactions. The potential for enhancement of ozone depletions through the presence of iodine-containing molecules (I{sub 2}, IBr, ICl, CH{sub 2}I{sub 2}, CH{sub 2}IBr, CH{sub 2}ICl, and CH{sub 3}I) is investigated in this study. Computer simulations of the homogeneous chemistry are made using a reasonably complete reaction mechanism for Br-, Cl- and I-containing species together with representative chemistry of trace gases in the clean troposphere. The extent of uncertain alternative pathways and efficiencies for OIO and I{sub 2}O{sub 2} photolyses are varied over a range of possible values to establish the sensitivity of the depletion events to these variables. The study shows that significant enhancements of the polar ozone depletion are expected when small amounts of iodine-containing compounds such as CH{sub 2}I{sub 2}, IBr, or ICl are present in a polar air mass containing representative Br{sub 2}-BrCl-trace gas mixtures. The synergistic effect of the iodine compounds results from additional halogen-atom formation from IO-IO, IO-BrO, and IO-ClO reactions. Measurements of IO and precursor iodine-containing compounds are encouraged for future polar spring studies, as well as currently acknowledged important trace species (O{sub 3}, CH{sub 2}O, BrO, Br{sub 2}, and BrCl).

  15. Identification of phenolic compounds from lingonberry (Vaccinium vitis-idaea L.), bilberry (Vaccinium myrtillus L.) and hybrid bilberry (Vaccinium x intermedium Ruthe L.) leaves.

    PubMed

    Hokkanen, Juho; Mattila, Sampo; Jaakola, Laura; Pirttilä, Anna Maria; Tolonen, Ari

    2009-10-28

    Phenolic compounds from leaves of lingonberry (Vaccinium vitis-idaea L.), bilberry (Vaccinium myrtillus L.), and the natural hybrid of bilberry and lingonberry (Vaccinium x intermedium Ruthe L., hybrid bilberry) were identified using LC/TOF-MS and LC/MS/MS after extraction from the plant material in methanol in an ultrasonicator. The phenolic profiles in the plants were compared using the LC/TOF-MS responses. This is the first thorough report of phenolic compounds in hybrid bilberry. In total, 51 different phenolic compounds were identified, including flavan-3-ols, proanthocyanidins, flavonols and their glycosides, and various phenolic acid conjugates. Of the identified compounds, 35 were detected in bilberry, 36 in lingonberry, and 46 in the hybrid. To our knowledge, seven compounds were previously unreported in Vaccinium genus and many of the compounds are reported for the first time from bilberry and lingonberry. PMID:19788243

  16. Effect of lattice constant on pseudo Jahn-Teller polar distortion: Application to search for new multiferroic compounds

    NASA Astrophysics Data System (ADS)

    Song, Guang; Zhang, Weiyi

    2016-08-01

    By analog to Maxwell construction for the first-order phase transition, the pseudo Jahn-Teller polar distortion arises naturally once the local bond length of transition-metal oxygen octahedra is enhanced beyond the inflexion point of pair potential into the concave-down dominated region. This concept is applied to search for the new multiferroic compounds for which we specifically choose the (BaMnO3)1/(BaFeO3)1 superlattice as a candidate. The large Ba radius favors the polar distortion in a BaMnO3 layer, while the orbital-ordering-induced superexchange ferromagnetic coupling among Fe-Fe and double-exchange mediated ferromagnetic coupling among Fe-Mn ions stabilize the overall ferromagnetic insulator. A large magnetic moment of 7 μB per unit cell and electric polarization of 14.4 μ Ccm -2 are obtained. Our study offers an important insight for designing robust multiferroic compounds in the future.

  17. Multi-compound polarization by DNP allows simultaneous assessment of multiple enzymatic activities in vivo

    NASA Astrophysics Data System (ADS)

    Wilson, David M.; Keshari, Kayvan R.; Larson, Peder E. Z.; Chen, Albert P.; Hu, Simon; Van Criekinge, Mark; Bok, Robert; Nelson, Sarah J.; Macdonald, Jeffrey M.; Vigneron, Daniel B.; Kurhanewicz, John

    2010-07-01

    Methods for the simultaneous polarization of multiple 13C-enriched metabolites were developed to probe several enzymatic pathways and other physiologic properties in vivo, using a single intravenous bolus. A new method for polarization of 13C sodium bicarbonate suitable for use in patients was developed, and the co-polarization of 13C sodium bicarbonate and [1- 13C] pyruvate in the same sample was achieved, resulting in high solution-state polarizations (15.7% and 17.6%, respectively) and long spin-lattice relaxation times ( T1) (46.7 s and 47.7 s respectively at 3 T). Consistent with chemical shift anisotropy dominating the T1 relaxation of carbonyls, T1 values for 13C bicarbonate and [1- 13C] pyruvate were even longer at 3 T (49.7 s and 67.3 s, respectively). Co-polarized 13C bicarbonate and [1- 13C] pyruvate were injected into normal mice and a murine prostate tumor model at 3 T. Rapid equilibration of injected hyperpolarized 13C sodium bicarbonate with 13C CO 2 allowed calculation of pH on a voxel by voxel basis, and simultaneous assessment of pyruvate metabolism with cellular uptake and conversion of [1- 13C] pyruvate to its metabolic products. Initial studies in a Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) model demonstrated higher levels of hyperpolarized lactate and lower pH within tumor, relative to surrounding benign tissues and to the abdominal viscera of normal controls. There was no significant difference observed in the tumor lactate/pyruvate ratio obtained after the injection of co-polarized 13C bicarbonate and [1- 13C] pyruvate or polarized [1- 13C] pyruvate alone. The technique was extended to polarize four 13C labelled substrates potentially providing information on pH, metabolism, necrosis and perfusion, namely [1- 13C]pyruvic acid, 13C sodium bicarbonate, [1,4- 13C]fumaric acid, and 13C urea with high levels of solution polarization (17.5%, 10.3%, 15.6% and 11.6%, respectively) and spin-lattice relaxation values similar to those

  18. Synthesis and solvent-dependent photochromic reactions of porphyrin-spiropyran hybrid compounds

    NASA Astrophysics Data System (ADS)

    Hur, Dae Young; Park, Tae Jong; Shin, Eun Ju

    2014-01-01

    Porphyrin(Por)-spiropyran(SP) hybrid compounds, including Por-SP dyad, Por-SP2 triad, and Por-SP4 pentad, were prepared and characterized by 1H NMR, MALDI-TOF MS and UV-Vis spectroscopies. Upon 350 nm UV irradiation of Por-SPn (n = 1, 2, 4) in dichloromethane, unusual red-shifted absorption spectra were observed with the colour change from pink into green. Probably due to the protonation of core nitrogens in porphyrin ring, their absorption maxima in dichloromethane were shifted from 418 (Soret band), 515, 550, 590, 645 (four Q bands) nm into 450 and 665 nm. Also, fluorescence maxima were also shifted from 650 and 715 nm to 692 nm. In the other hands, upon irradiation with 350 nm UV light in THF, the colour changed from pink into violet and absorption band at 590 nm increased and the fluorescence spectra showed the decrease of 650 and 715 nm bands and increase of 600-640 nm band, due to the normal ring-opening reaction of spiropyran moiety into merocyanine. In the dark, original absorption and fluorescence spectra were recovered very slowly in dichloromethane, but quickly in THF. The reversible photochromic reactions of Por-SPn (n = 1, 2, 4) in dichloromethane and THF were investigated by observing absorption and fluorescence spectral changes during UV irradiation or standing in the dark.

  19. Model-based predictions of solid state intermetallic compound layer growth in hybrid microelectronic circuits

    SciTech Connect

    Vianco, P.T.; Erickson, K.L.; Hopkins, P.L.

    1997-12-31

    A mathematical model was developed to quantitatively describe the intermetallic compound (IMC) layer growth that takes place between a Sn-based solder and a noble metal thick film conductor material used in hybrid microcircuit (HMC) assemblies. The model combined the reaction kinetics of the solder/substrate interaction, as determined from ancillary isothermal aging experiments, with a 2-D finite element mesh that took account of the porous morphology of the thick film coating. The effect of the porous morphology on the IMC layer growth when compared to the traditional 1-D computations was significant. The previous 1-D calculations under-predicted the nominal IMC layer thickness relative to the 2-D case. The 2-D model showed greater substrate consumption by IMC growth and lesser solder consumption that was determined with the 1-D computation. The new 2-D model allows the design engineer to better predict circuit aging and hence, the reliability of HMC hardware that is placed in the field.

  20. SCC-DFTB parameters for simulating hybrid gold-thiolates compounds.

    PubMed

    Fihey, Arnaud; Hettich, Christian; Touzeau, Jérémy; Maurel, François; Perrier, Aurélie; Köhler, Christof; Aradi, Bálint; Frauenheim, Thomas

    2015-10-15

    We present a parametrization of a self-consistent charge density functional-based tight-binding scheme (SCC-DFTB) to describe gold-organic hybrid systems by adding new Au-X (X = Au, H, C, S, N, O) parameters to a previous set designed for organic molecules. With the aim of describing gold-thiolates systems within the DFTB framework, the resulting parameters are successively compared with density functional theory (DFT) data for the description of Au bulk, Aun gold clusters (n = 2, 4, 8, 20), and Aun SCH3 (n = 3 and 25) molecular-sized models. The geometrical, energetic, and electronic parameters obtained at the SCC-DFTB level for the small Au3 SCH3 gold-thiolate compound compare very well with DFT results, and prove that the different binding situations of the sulfur atom on gold are correctly described with the current parameters. For a larger gold-thiolate model, Au25 SCH3 , the electronic density of states and the potential energy surfaces resulting from the chemisorption of the molecule on the gold aggregate obtained with the new SCC-DFTB parameters are also in good agreement with DFT results. PMID:26280464

  1. GaN-nanowire/ TiO2-nanocluster hybrid sensors for detection of Benzene and related aromatic compounds

    NASA Astrophysics Data System (ADS)

    Aluri, Geetha S.; Motayed, Abhishek; Davydov, Albert V.; Oleshko, Vladimir; Bertness, Kris A.; Sanford, Norman A.; Rao, Mulpuri V.

    2011-05-01

    Nanowire-nanocluster hybrid chemical sensors were realized by functionalizing gallium nitride (GaN) nanowires with titanium dioxide (TiO2) nanoclusters for selectively sensing Benzene and other related aromatic compounds. Hybrid sensor devices were developed by fabricating two-terminal devices using individual GaN nanowires followed by the deposition of TiO2 nanoclusters using RF magnetron sputtering. The sensor fabrication process employed all standard micro-fabrication techniques. A change of current was observed for these hybrid sensors when exposed to aromatic compounds such as Benzene, Toluene, Ethylbenzene, Xylene, and Chlorobenzene mixed with air. However, these sensors did not show any sensitivity when exposed to Methanol, Ethanol, Isopropanol, Chloroform, Acetone, and 1, 3-Hexadiene. These sensors were capable of sensing the aromatic compounds only under ultraviolet excitation. The sensitivity range for the above mentioned aromatic compounds varied from 1% down to 50 parts per billion (ppb) at room-temperature. By combining the enhanced catalytic properties of the TiO2 nanoclusters with the sensitive transduction capability of the nanowires, an ultra-sensitive and highly selective chemical sensing architecture is demonstrated. We have proposed a mechanism that could qualitatively explain the observed sensing behavior.

  2. A new analytical approach for the comprehensive characterization of polar xenobiotic organic compounds downgradient of old municipal solid waste (MSW) landfills.

    PubMed

    Preiss, A; Berger-Preiss, E; Elend, M; Gerling, S; Kühn, S; Schuchardt, S

    2012-07-01

    Groundwater samples collected downgradient from a former municipal solid waste landfill near Berlin, Germany, were analyzed by GC-MS, HPLC-MS, and HPLC-NMR hyphenated techniques to comprehensively characterize the xenobiotic organic compounds (XOCs). The focus thereby was on the detection and identification of the polar XOCs which were analyzed in the extract obtained after separation of the unpolar components by pre-extraction. HPLC-NMR and HPLC-MS runs were used to identify polar XOCs on-line or to obtain preliminary structure information on the other XOCs. These compounds were then isolated by HPLC fractionation and their structures elucidated by off-line NMR and MS investigations. A variety of polar XOCs, products of the dye industry, degradation products of polyethylene glycol, and some heterocyclic compounds could be identified. Furthermore, a semi-quantitative estimation of the identified polar compounds is given. PMID:22526634

  3. Petroleum alteration by thermochemical sulfate reduction - A comprehensive molecular study of aromatic hydrocarbons and polar compounds

    NASA Astrophysics Data System (ADS)

    Walters, Clifford C.; Wang, Frank C.; Qian, Kuangnan; Wu, Chunping; Mennito, Anthony S.; Wei, Zhibin

    2015-03-01

    Thermochemical sulfate reduction (TSR) alters petroleum composition as it proceeds towards the complete oxidation of hydrocarbons to CO2. The effects of TSR on the molecular and isotopic composition of volatile species are well known; however, the non-volatile higher molecular weight aromatic and polar species have not been well documented. To address this deficiency, a suite of onshore Gulf coast oils and condensates generated from and accumulating in Smackover carbonates was assembled to include samples that experienced varying levels of TSR alteration and in reservoir thermal cracking. The entire molecular composition of aromatic hydrocarbons and NSO species were characterized and semi-quantified using comprehensive GC × GC (FID and CSD) and APPI-FTICR-MS. The concentration of thiadiamondoids is a reliable indicator of the extent of TSR alteration. Once generated by TSR, thiadiamondoids remain thermally stable in all but the most extreme reservoir temperatures (>180 °C). Hydrocarbon concentrations and distributions are influenced by thermal cracking and TSR. With increasing TSR alteration, oils become enriched in monoaromatic hydrocarbons and the distribution of high molecular weight aromatic hydrocarbons shifts towards more condensed species with a decrease in the number of alkyl carbons. Organosulfur compounds are created by the TSR process. In addition to the increase in benzothiophenes and dibenzothiophenes noted in previous studies, TSR generates condensed species containing one or more sulfur atoms that likely are composed of a single or multiple thiophenic cores. We hypothesize that these species are generated from the partial oxidation of PAHs and dealkylation reactions, followed by sulfur incorporation and condensation reactions. The organosulfur species remaining in the TSR altered oils are "proto-solid bitumen" moieties that upon further condensation, oxidation or sulfur incorporation result in highly sulfur enriched solid bitumen, which is

  4. Effect of light on the polarization of a banana-shaped achiral compound doped with a photoactive azobenzene material

    SciTech Connect

    Nair, Geetha G.; Prasad, S. Krishna; Hiremath, Uma S.; Yelamaggad, C. V.

    2001-07-01

    We report photoinduced effects on a liquid crystal comprising of bent-core molecules, doped with a photoactive azobenzene compound and exhibiting the recently discovered {open_quotes}banana{close_quotes} B{sub 2} mesophase. The photoisomerization of the azobenzene molecules, brought about by the UV radiation, hardly changes the B{sub 2}-isotropic transition temperatures, but has a significant influence on the spontaneous polarization (Ps) as well as the switching time in the B{sub 2} phase. The efficiency of this opto-polarization effect has been observed to be strongly dependent on the temperature at which the irradiation is carried out. A possible mechanism responsible for the observed phenomenon has been suggested. {copyright} 2001 American Institute of Physics.

  5. Polarization holographic gratings in hybrid solgel films doped with Disperse Red 1.

    PubMed

    Raschellà, Raffaella; Marino, Iari-Gabriel; Lottici, Pier Paolo; Bersani, Danilo

    2003-11-15

    Polarization holographic gratings in sp configuration are written at 488 nm in photorefractive organic-inorganic films based on SiO2. The films, prepared by a solgel technique, contain Disperse Red 1, carbazole units, and 2,4,7-trinitro-9-fluorenone. The gratings are characterized by their diffraction efficiency for a 632.8-nm probe. The polarization gratings act as a half-wave plate, and the diffraction efficiency is independent of the polarization direction of the probe. PMID:14649954

  6. Correlation of soil and sediment organic matter polarity to aqueous sorption of nonionic compounds

    USGS Publications Warehouse

    Kile, D.E.; Wershaw, R. L.; Chiou, C.T.

    1999-01-01

    Polarities of the soiL/sediment organic matter (SOM) in 19 soil and 9 freshwater sediment sam pies were determined from solid-state 13C-CP/MAS NMR spectra and compared with published partition coefficients (K(oc)) of carbon tetrachloride (CT) from aqueous solution. Nondestructive analysis of whole samples by solid-state NMR permits a direct assessment of the polarity of SOM that is not possible by elemental analysis. The percent of organic carbon associated with polar functional groups was estimated from the combined fraction of carbohydrate and carboxylamide-ester carbons. A plot of the measured partition coefficients (K(oc)) of carbon tetrachloride (CT) vs. percent polar organic carbon (POC) shows distinctly different populations of soils and sediments as well as a roughly inverse trend among the soil/sediment populations. Plots of K(oc) values for CT against other structural group carbon fractions did not yield distinct populations. The results indicate that the polarity of SOM is a significant factor in accounting for differences in K(oc) between the organic matter in soils and sediments. The alternate direct correlation of the sum of aliphatic and aromatic structural carbons with K(oc) illustrates the influence of nonpolar hydrocarbon on solute partition interaction. Additional elemental analysis data of selected samples further substantiate the effect of the organic matter polarity on the partition efficiency of nonpolar solutes. The separation between soil and sediment samples based on percent POC reflects definite differences of the properties of soil and sediment organic matters that are attributable to diagenesis.Polarities of the soil/sediment organic matter (SOM) in 19 soil and 9 freshwater sediment samples were determined from solid-state 13C-CP/MAS NMR spectra and compared with published partition coefficients (Koc) of carbon tetrachloride (CT) from aqueous solution. Nondestructive analysis of whole samples by solid-state NMR permits a direct

  7. Organic high ionic strength aqueous two-phase solvent system series for separation of ultra-polar compounds by spiral high-speed counter-current chromatography

    PubMed Central

    Zeng, Yun; Liu, Gang; Ma, Ying; Chen, Xiaoyuan; Ito, Yoichiro

    2011-01-01

    Existing two-phase solvent systems for high-speed countercurrent chromatography cover the separation of hydrophobic to moderately polar compounds, but often fail to provide suitable partition coefficient values for highly polar compounds such as sulfonic acids, catecholamines and zwitter ions. The present paper introduces a new solvent series which can be applied for the separation of these polar compounds. It is composed of 1-butanol, ethanol, saturated ammonium sulfate and water at various volume ratios and consists of a series of 10 steps which are arranged according to the polarity of the solvent system so that the two-phase solvent system with suitable K values for the target compound(s) can be found in a few steps. Each solvent system gives proper volume ratio and high density difference between the two phases to provide a satisfactory level of retention of the stationary phase in the spiral column assembly. The method is validated by partition coefficient measurement of four typical polar compounds including methyl green (basic dye), tartrazine (sulfonic acid), tyrosine (zwitter ion) and epinephrine (a catecholamine), all of which show low partition coefficient values in the polar 1-butanol-water system. The capability of the method is demonstrated by separation of three catecholamines. PMID:22033108

  8. Preparation of Core-Shell Hybrid Compounds by Atomic Transfer Radical Polymerization and Its Application to Plastic Lens of Headlamp.

    PubMed

    Noh, Seung-Man; Ahn, Jae-Beum; Choi, Ki-Hyun; Park, Seung-Kyu

    2015-09-01

    Nano silica ball (NSB) core polymethylmethacrylate (PMMA) shell hybrid nanocomposites were synthesized by atomic transfer radical polymerization (ATRP) method for the application to the clearcoat to enhance scratch resistance. The characteristics of the synthesized inorganic/organic hybrid material were examined by scanning electron microscope (SEM), particle size analysis, Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis-differential scanning calorimetry (TGA-DSC). The scratch resistance and light transmittance of the clearcoat were measured by a nano-scratch tester and UV-visible spectroscopy, respectively. The average particle size of the NSB-PMMA hybrid compounds was 30 nm with narrow size distribution. Even 0.1 wt% loading of NSB-PMMA in the clearcoat dramatically enhanced the scratch resistance, about 40% increase in the force of the first fracture, while slightly reduced the light transmittance, about 5% only. PMID:26716303

  9. Development of an in situ derivatization technique for rapid analysis of levoglucosan and polar compounds in atmospheric organic aerosol

    NASA Astrophysics Data System (ADS)

    Sheesley, Rebecca J.; Mieritz, Mark; DeMinter, Jeff T.; Shelton, Brandon R.; Schauer, James J.

    2015-12-01

    A novel thermal desorption gas chromatography mass spectrometry (TD-GCMS) technique was developed for the analysis of levoglucosan and other polar compounds in atmospheric organic aerosol. The method employs an in situ derivatization to add tri-methylsilyl groups to alcohol functional groups on simple carbohydrates, like levoglucosan and sterols. The new method was then demonstrated on a set of 40 filter samples collected in Fresno, CA. The results from the in situ silylation TD-GCMS method were compared, using levoglucosan, with a solvent extraction, high-volume injection GCMS method resulting in an r2 = 0.91.

  10. Development of an in situ derivatization technique for rapid analysis of levoglucosan and polar compounds in atmospheric organic aerosol

    NASA Astrophysics Data System (ADS)

    Sheesley, Rebecca J.; Mieritz, Mark; DeMinter, Jeff T.; Shelton, Brandon R.; Schauer, James J.

    2015-12-01

    A novel thermal desorption gas chromatography mass spectrometry (TD-GCMS) technique was developed for the analysis of levoglucosan and other polar compounds in atmospheric organic aerosol. The method employs an in situ derivatization to add tri-methylsilyl groups to alcohol functional groups on simple carbohydrates, like levoglucosan and sterols. The new method was then demonstrated on a set of 40 filter samples collected in Fresno, CA. The results from the in situ silylation TD-GCMS method were compared, using levoglucosan, with a solvent extraction, high-volume injection GCMS method resulting in an r2 = 0.91.

  11. Anomalous temperature dependence of gas chromatographic retention indices of polar compounds on nonpolar phases

    NASA Astrophysics Data System (ADS)

    Zenkevich, I. G.; Pavlovskii, A. A.

    2016-05-01

    The character of the temperature dependences of the retention indices RI( T) of polar sorbates on nonpolar stationary phases was found to depend on the dosed amounts of sorbates, but not on column overloading. A physicochemical model was suggested to explain the observed anomalies in RI( T).

  12. Non-polar halogenated natural products bioaccumulated in marine samples. II. Brominated and mixed halogenated compounds.

    PubMed

    Vetter, Walter; Jun, Wu

    2003-07-01

    Several identified and potential natural brominated bioaccumulative compounds were studied in this work. 4,6-dibromo-2-(2('),4(')-dibromo)phenoxyanisole (BC-2) previously detected in Australian marine mammals and isolated from sponges, was synthesized. Two byproducts (a tetrabromo isomer and a tribromo congener) were investigated as well. The byproducts of the synthesis were not identified in the environmental samples investigated. Previously described natural brominated compounds (BC-1, BC-2, BC-3, BC-10, BC-11, MHC-1) and anthropogenic brominated diphenyl ethers (BDE-47, BDE-99, BDE-100, BDE-154) were detected in a sample of human milk. The sample was from a woman from the Faeroe Islands who frequently consumed fish as well as whale blubber and meat. The most abundant compound originated from the natural tetrabromo phenoxyanisole BC-3 which may have a 3:1 distribution of bromine on the two phenyl units. This sample also accumulated a dibromochloroanisole, as well as a previously unknown mixed halogenated compound (MHC-X) and an unknown, most likely aromatic brominated compound. Co-elutions on a DB-5 column were found for BDE-99 and BC-11 as well as BDE-154 and the unknown brominated compound. This suggests that quantification of these two compounds has to be carried out carefully.Two samples of lower trophic level, namely Baltic cod liver and Mexican mussel tissue, were investigated as well. The cod liver samples contained BDE congeners but also abundant signals for the natural 2,3,3('),4,4('),5,5(')-heptachloro-1(')-methyl-1,2(')-bipyrrole Q1 and tribromoanisole (TBA). The mussel sample contained Q1, TBA, another halogenated anisole, BC-1, BC-2, and BC-3, as well as additional, potential natural brominated compounds in the elution range of tribromophenoxyanisoles. PMID:12738265

  13. Two New Organo-Inorganic Hybrid Compounds: Nitrilophosphonates of Aluminum and Copper

    NASA Astrophysics Data System (ADS)

    Cabeza, Aurelio; Bruque, Sebastián; Guagliardi, Antonietta; Aranda, Miguel A. G.

    2001-08-01

    Two new organo-inorganic hybrid compounds, aluminum nitrilotris(methylene)trismonohydrogenphosphonate hydrate, Al[(HO3PCH2)3N]H2O, and tricopper(II) bis-nitrilobis(methylene)diphosphonate, Cu3[(O3PCH2)2NH2]2, have been synthesized. The crystal structures have been determined ab initio from powder diffraction data and refined by the Rietveld method. Al[(HO3PCH2)3N]H2O is monoclinic, space group P21/n, with a=12.1945(3) Å, b=9.1129(3) Å, c=8.5495(2) Å, β=94.317(2)°, Z=4, and the X-ray powder diffraction pattern has been refined to RwP=8.7%. Cu3[(O3PCH2)2NH2]2 is orthorhombic, space group Pbca, with a=16.1209(6) Å, b=9.4890(4) Å, c=9.4113(4) Å, Z=4 and its pattern was refined to RwP=13.5%. The crystal structure of aluminum phosphonate contains a close packing of inorganic chains, formed by alternating AlO6 octahedra and O3PC tetrahedra. These chains are covalently interconnected by the organic groups to give the 3D framework. The structure of copper phosphonate has two distinct copper environments, one a tetragonally elongated tetrahedron and the other a distorted square plane. These structural units are linked by the organic phosphonate. Thermal and infrared data are discussed.

  14. Electromagnetic Components of Auroral Hiss and Lower Hybrid Waves in the Polar Magnetosphere

    NASA Technical Reports Server (NTRS)

    Wong, H. K.

    1995-01-01

    DE-1 has frequently observed waves in the whistler and lower hybrid frequencies range. Besides the electrostatic components, these waves also exhibit electromagnetic components. It is generally believed that these waves are excited by the electron acoustic instability and the electron-beam-driven lower hybrid instability. Because the electron acoustic and the lower hybrid waves are predominately electrostatic waves, they cannot account for the observed electromagnetic components. In this work, it is suggested that these electromagnetic components can be explained by waves that are generated near the resonance cone and that propagate away from the source. The role that these electromagnetic waves can play in particle acceleration processes at low altitude is discussed.

  15. Semiconductor superlattice diodes for detection of terahertz photons: The role of hybridization of the plasma and polar-optical phonon modes

    SciTech Connect

    Ignatov, Anatoly A.

    2014-08-28

    The current (voltage) responsivity of a superlattice-based diode detector has been studied theoretically in the terahertz frequency band that includes the region of the polar-optical phonon frequencies. Within the framework of an equivalent circuit approach, the electro-dynamical model which allows one to analyze the responsivity taking into account the hybridization of the plasma and polar-optical phonon modes both in the substrate and in the cladding layers of the diode has been suggested. It has been shown that the presence of the plasma and polar-optical phonon modes gives rise to strong features in the frequency dependence of the responsivity, i.e., to the resonance dips and peaks at frequencies of hybridized plasmons and polar-optical phonons. It has been suggested that by judicious engineering of the superlattice-based diodes, it would be possible to enhance substantially their responsivity in the terahertz frequency band.

  16. Cross polarization and magic angle sample spinning NMR spectra of model organic compounds. 1. Highly protonated molecules

    SciTech Connect

    Alemany, L.B.; Grant, D.M.; Pugmire, R.J.; Alger, T.D.; Zilm, K.W.

    1983-04-20

    CP/MAS /sup 13/C NMR spectra were obtained at various contact times on ten solid organic compounds containing a variety of simple functional groups. The spectra show that signal intensities that agree with atomic ratios can be obtained with a contact time of 2.25 ms and often with a contact time as short as about 1 ms. Computer analysis of signal intensities obtained at a minimum of ten different contact times provides T/sub CH/ data that are consistent with these experimental results. The experimental results are also consistent with the previously reported lack of significant variation in the spectra of complex organic solids obtained with contact times of about 1 to 3 ms. In general, nonprotonated carbon atoms polarize more slowly than protonated carbon atoms. The compounds exhibit a wide range of proton spin lattice relaxation times. Some compounds exhibit more resonances than are found in the /sup 13/C(/sup 1/H) spectra of the compounds in solution because the crystalline environment removes the nominal spatial equivalence found for carbon atoms related to each other by unimolecular symmetry elements.

  17. Ambient gas/particle partitioning. 3. Estimating partition coefficients of apolar, polar, and ionizable organic compounds by their molecular structure.

    PubMed

    Arp, Hans Peter H; Gosses, Kai-Uwe

    2009-03-15

    Equilibrium gas/particle partitioning coefficients of terrestrial aerosols, Kip, are dependent on various intermolecular interactions that can be quantified by experimentally determined compound-specific descriptors. For many compounds of environmental interest, such as emerging contaminants and atmospheric phototransformation products, these compound-specific descriptors are unknown or immeasurable. Often, only the molecular structure is known. Here we present the ability of two computer programs to predict equilibrium partitioning to terrestrial aerosols solely on the basis of molecular structure: COSMOtherm and SPARC. The greatest hurdle with designing such an approach is to identify suitable molecular surrogates to represent the dominating sorbing phases, which for ambient terrestrial aerosols are the water insoluble organic matter (WIOM) phase and the mixed-aqueous phase. For the WI0M phase, hypothetical urban secondary organic aerosol structural units from Kalberer et al. Science 2004, 303, 1659-1662 were investigated as input surrogates, and for the mixed-aqueous phase mildly acidic water was used as a surrogate. Using a validation data set of more than 1400 experimentally determined Kip values for polar, apolar, and ionic compounds ranging over 9 orders of magnitude (including semivolatile compounds such as PCDD/Fs, pesticides, and PBDEs), SPARC and COSMOtherm were generally able to predict Kip values well within an order of magnitude over an ambient range of temperature and relative humidity. This is remarkable as these two models were not fitted or calibrated to any experimental data. As these models can be used for potentially any organic molecule, they are particularly recommended for environmental screening purposes and for use when experimental compound descriptor data are not available. PMID:19368193

  18. Detection of flavor compounds in longissimus muscle from four hybrid pig breeds of Sus scrofa, Bamei pig, and Large White.

    PubMed

    Chen, Guoshun; Sui, Yanan; Chen, Sheng

    2014-01-01

    To detect the flavor quality and flavor compounds in raw longissimus muscle from four typical pig breeds: Sus scrofa × Bamei pig named F1 (group A), F1 × F1 (group B), F1 × Bamei pig (group C), and F1 × Large White (group D). The chemical compositions of longissimus muscles from four breeds were examined using headspace solid-phase microextraction/gas chromatography mass spectrometry method. Distinct differences for the same flavor compounds of longissimus muscles between different breeds were analyzed. Totally 64 flavor compounds shared in four groups, and 10 flavor compounds with significant difference among four groups (p < 0.05), including allyl butyrate, (Z)-2-penten-1-ol, 2,2-dimethyl-3-methyl oxirane, 2-pentylfuran, dodecane, 2,4-decadienal, vinylsilane, 3-methyl-1-butanol, (1-methyldecyl)-benzene, and dipropyl phthalate. Totally, 23-41 flavor compounds did not commonly exist in four groups, such as only as dibutyl isophthalate in group A; 6,10-dimethyl-5-9-undecadien-2 one, bis (2-trimethylsilyl) ethyl ester-malonic acid, heptadecane, 2,4,6-trimethyl pyridine, and diisooctyl adipate in group C alone; and 1,3-dimethylcyclopentanol, 2-octanone, and trimethylsilane in group D alone. While, no specific flavor compounds were identified in group B. All these flavor compounds covered 12 types of hydrocarbons, alcohols, aldehydes, hydroxybenzenes, acids, ketones, esters, sulfides, furans, alkenes, and pyrrole. Besides, we analyzed 14 flavor compounds with different flavors combining with previous studies. The flavor compounds in longissimus muscles might be closely related to the breeds, and the hybrid of S. scrofa × Bamei pig had the most flavor compounds in raw longissimus muscle. PMID:25052201

  19. Weak hybridization and isolated localized magnetic moments in the compounds CeT2Cd20 (T = Ni, Pd)

    NASA Astrophysics Data System (ADS)

    White, Benjamin; Yazici, Duygu; Ho, Pei-Chun; Kanchanavatee, Noravee; Pouse, Naveen; Friedman, Aaron; Maple, M. Brian

    2015-03-01

    Large Ce-Ce distances of 6.7-6.8 Åand weak hybridization between Ce 4 f and itinerant electron states act to promote stable localized magnetic moments in the compounds CeT2Cd20 (T = Ni, Pd), but also conspire to severely limit the strength of the Ruderman-Kittel-Kasuya-Yosida (RKKY) magnetic exchange interaction that couples them. As a consequence, measurements of electrical resistivity, performed on single-crystalline samples of these new Cd-based compounds down to 0.138 K, were unable to resolve any evidence for magnetic order. In this presentation, we will compare measurements of the physical properties of CeT2Cd20 (T = Ni, Pd) under ambient and applied pressures with the reported properties of the isostructural compounds CeT2X20 (T = transition metal; X = Al, Zn). We will use these comparisons to discuss the interplay of unit cell volume, hybridization, and the RKKY interaction and its role in establishing the ground states of the Ce-based ``1-2-20'' compounds. Sample synthesis and physical properties measurements were supported by the U.S. DOE under Grant No. DE-FG02-04-ER46105. Measurements of electrical resistivity below 1 K were supported by the NSF under Grants No. DMR-1206553 and No. DMR-1104544.

  20. Fluid and hybrid modeling of nanosecond surface discharges: effect of polarity and secondary electrons emission

    NASA Astrophysics Data System (ADS)

    Babaeva, Natalia Yu; Tereshonok, Dmitry V.; Naidis, George V.

    2016-08-01

    In this paper, we report on results from a computational investigation of nanosecond pulsed surface discharges of positive and negative polarity using a 2D fluid and fluid-Monte Carlo simulation. The streamers propagate along the dielectric surface in an asymmetric actuator geometry. The essential difference between the streamers of positive and negative polarities is observed. For positive polarity the intense sheath region is formed near the surface having high values of the electric field. The negative streamer has a lower field at the streamer front and in the sheath region. The disparity between the positive and negative surface streamers increases when electron Monte Carlo simulation is used that treats the energetic secondary electrons in a fully kinetic way. We also found that for a negative polarity applied to the exposed electrode, a thin layer of precursor electrons ahead of a streamer is formed having a shape of a narrow protruding needle. The effect is attributed to the production and trapping of fast secondary electrons in the narrow anodic sheath region.

  1. Structure-Triggered High Quantum Yield Luminescence and Switchable Dielectric Properties in Manganese(II) Based Hybrid Compounds.

    PubMed

    Wang, Zhong-Xia; Li, Peng-Fei; Liao, Wei-Qiang; Tang, Yuanyuan; Ye, Heng-Yun; Zhang, Yi

    2016-04-01

    Two new manganese(II) based organic-inorganic hybrid compounds, C11 H21 Cl3 MnN2 (1) and C11 H22 Cl4 MnN2 (2), with prominent photoluminescence and dielectric properties were synthesized by solvent modulation. Compound 1 with novel trigonal bipyramidal geometry exhibits bright red luminescence with a lifetime of 2.47 ms and high quantum yield of 35.8 %. Compound 2 with tetrahedral geometry displays intense long-lived (1.54 ms) green light emission with higher quantum yield of 92.3 %, accompanied by reversible solid-state phase transition at 170 K and a distinct switchable dielectric property. The better performance of 2 results from the structure, including a discrete organic cation moiety and inorganic metal anion framework, which gives the cations large freedom of motion. PMID:26864910

  2. ANALYSIS OF AMBIENT POLAR VOLATILE ORGANIC COMPOUNDS USING CHEMICAL IONIZATION -- ION TRAP DETECTOR

    EPA Science Inventory

    The current approach to measuring trace levels of volatile organic compounds (VOCs) in ambient air requires cryogenic trapping of the analytes, followed by thermal desorption and low-temperature refocussing onto a column for analysis by capillary gas chromatography/mass spectrome...

  3. Headspace analysis of polar organic compounds in biological matrixes using solid phase microextraction (SPME)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Analysis of biological fluids and waste material is difficult and tedious given the sample matrix. A rapid automated method for the determination of volatile fatty acids and phenolic and indole compounds was developed using a multipurpose sampler (MPS) with solid phase microextraction (SPME) and GC-...

  4. Determinatin of the Dipole Moment of Polar Compounds in Nonpolar Solvents.

    ERIC Educational Resources Information Center

    Janini, George M.; Katrib, Ali H.

    1983-01-01

    Proposes a simple experiment based on the procedure of Guggenheim and Smith for the determinatin of the dipole moments of two isomeric compounds in nonpolar solvents. Provides background information, laboratory procedures, sample data, results of least squares analysis and discussion of results. (JM)

  5. NON-POLAR VOLATILE ORGANIC COMPOUNDS IN WHOLE AIR SAMPLES FROM THE AUTOEX STUDIES

    EPA Science Inventory

    Air samples were captured in SUMMA polished stainless steel canisters and returned to the laboratory for analysis of trace level volatile organic compounds by gas chromatography - mass spectrometry. ampling was performed over 2-hour periods at various distances from heavily trave...

  6. A comprehensive quantification method for eicosanoids and related compounds by using liquid chromatography/mass spectrometry with high speed continuous ionization polarity switching.

    PubMed

    Yamada, Masaki; Kita, Yoshihiro; Kohira, Takahiro; Yoshida, Kenji; Hamano, Fumie; Tokuoka, Suzumi M; Shimizu, Takao

    2015-07-15

    Fatty acids and related metabolites, comprising several hundreds of molecular species, are an important target in disease metabolomics, as they are involved in various mammalian pathologies and physiologies. Selected reaction monitoring (SRM) analysis, which is capable of monitoring hundreds of compounds in a single run, has been widely used for comprehensive quantification. However, it is difficult to monitor a large number of compounds with different ionization polarity, as polarity switching requires a sub-second period per cycle in classical mass spectrometers. In the present study, we developed and evaluated a comprehensive quantification method for eicosanoids and related compounds by using LC/MS with high-speed continuous ionization polarity switching. The new method employs a fast (30ms/cycle) continuous ionization polarity switching, and differentiates 137 targets either by chromatography or by SRM transition. Polarity switching did not affect the lower limits of quantification, which ranged similarly from 0.5 to 200pg on column. Lipid extracts from mouse tissues were analyzed by this method, and 65 targets were quantitatively detected in the brain, including 6 compounds analyzed in the positive ion mode. We demonstrated that a fast continuous ionization polarity switching enables the quantification of a wide variety of lipid mediator species without compromising the sensitivity and reliability. PMID:26046978

  7. Parametric excitation of coupled fast and slow upper hybrid waves by counter-propagating circularly polarized lasers in a magnetized plasma

    NASA Astrophysics Data System (ADS)

    Verma, Kanika; Baliyan, Sweta; Sajal, Vivek; Kumar, Ravindra; Sharma, Navneet K.

    2016-07-01

    The parametric decay of large amplitude non-resonant beating mode of counter-propagating lasers (having a frequency difference ≥ 2 ω p ) into a pair of upper hybrid waves is studied in magnetized plasma. One of the excited upper hybrid waves (known as fast wave) having phase velocity close to c , can be utilized for electron acceleration. The coupled mode equations of fast and slow upper hybrid waves are modelled by solving equation of motion and continuity equation simultaneously (using the density perturbation technique) to derive the dispersion relation for two plasmon decay process. The growth rate of the present excitation process using right circularly polarized beating lasers is higher as compared with the growth rates of the excitation processes using ordinary and extraordinary beating lasers. However, the growth rate is not significant in the case of left circularly polarized beating lasers. The growth rate ˜ 0.15 ω p s - 1 is achieved for right circularly polarized beating lasers having v 1 , 2 / c = 0.1 for scattering angle θ s ˜ 160 ° and applied magnetic field ˜ 90 T. The growth rate of fast upper hybrid wave was reduced with the applied axial magnetic field in the present case. The present work is not only significant for the electron acceleration by fast upper hybrid wave but also for diagnostic purpose.

  8. Polar/apolar compounds induce leukemia cell differentiation by modulating cell-surface potential.

    PubMed Central

    Arcangeli, A; Carlà, M; Del Bene, M R; Becchetti, A; Wanke, E; Olivotto, M

    1993-01-01

    The mechanism of action of polar/apolar inducers of cell differentiation, such as dimethyl sulfoxide and hexamethylene-bisacetamide, is still obscure. In this paper evidence is provided that their effects on murine erythroleukemia cells are modulated by various extracellular cations as a precise function of the cation effects on membrane surface potential. The interfacial effects of the inducers were directly measured on the charged electrode, showing that both dimethyl sulfoxide and hexamethylene-bisacetamide, at the effective concentrations for cell differentiation and within the physiological range of charge density, adsorb at the charged surface and produce a potential shift. A linear correlation was found between this shift and the inducer effects on cell differentiation. Besides offering a different interpretation of the mechanism of action of the inducers, these findings indicate that surface potential has a signaling function. They may also be relevant to cancer treatments based on tumor-cell commitment to terminal differentiation. Images Fig. 1 PMID:8516337

  9. Polar intermetallic compounds of the silicon and arsenic family elements and their ternary hydrides and fluorides

    SciTech Connect

    Leon-Escamilla, E.A.

    1996-10-17

    An investigation has been made on the effects of hydrogen and fluoride in the solid state chemistry of alkaline-earth and divalent rare-earth metal pnictide (Pn) and tetrelide (Tt) phases A{sub 5}(Pn,Tt,){sub 3}Z{sub x}, where A = Ca, Sr, Ba, Sm, Eu, Yb; Pn = As, Sb, Bi; Tt = Si, Ge, Sn, Pb and Z = H, F. Several trivalent rare-earth-metal pnictides, RE{sub 5}Pn{sub 3} (RE = Y, La, Gd, Tb, Dy, Ho, Er, Tm) and alkaline-earth-metal trielides, A{sub 5}Tr{sub 3}Z{sub x} (Tr = Ga, In, Tl) have been included in an effort to complete observed structural trends. Two main experimental techniques were followed throughout this work, (a) reactions in absence of hydrogen or under continuous high vacuum, and (b) reactions with binary metal hydrides, AH{sub x}, in closed containers. The results demonstrate that all the phases reported with the {beta}-Yb{sub 5}Sb{sub 3}-type structure in the A{sub 5}Pn{sub 3} systems are hydrogen-stabilized compounds. Reactions in absence of hydrogen lead to compounds with the Mn{sub 5}Si{sub 3}-type structure. The structure type {beta}-Yb{sub 5}Sb{sub 3} (= Ca{sub 5}SB{sub 3}F) was found to be characteristic of ternary systems and inaccurately associated with phases that form in the Y{sub 5}Bi{sub 3}-type. A new series of isomorphous Zintl compounds with the Ca{sub 16}Sb{sub 11}-type structure were prepared and studied as well. All the alkaline-earth-metal tetrelides, A{sub 5}Tt{sub 3}, that crystallize in the Cr{sub 5}B{sub 3}-type structure can be interstitially derivatized by hydrogen or fluoride. Binary and ternary compounds were characterized by Guinier powder patterns, single crystal X-ray and powder neutron diffraction techniques. In an effort to establish property-structure relationships, electrical resistivity and magnetic measurements were performed on selected systems, and the results were explained in terms of the Zintl concepts, aided by extended Hueckel band calculations.

  10. Bibenzyl- and stilbene-core compounds with non-polar linker atom substituents as selective ligands for estrogen receptor beta.

    PubMed

    Waibel, Michael; De Angelis, Meri; Stossi, Fabio; Kieser, Karen J; Carlson, Kathryn E; Katzenellenbogen, Benita S; Katzenellenbogen, John A

    2009-09-01

    A series of structurally simple bibenzyl-diol and stilbene-diol core molecules, structural analogs of the well-known hexestrol and diethylstilbestrol non-steroidal estrogens, were prepared and evaluated as estrogen receptor (ER) subtype-selective ligands. Analysis of their ERalpha and ERbeta binding showed that certain substitution patterns engendered binding affinities that were >100-fold selective for ERbeta. When further investigated in cell-based gene transcription assays, some molecules showed similarly high relative transcriptional potency selectivity in favor of ERbeta. Interestingly, the most ERbeta-selective molecules were those bearing non-polar substituents on one of the internal carbon atoms. These compounds should be useful probes for determining the physiological roles of ERbeta, and they might lead to the development of more selective and thus safer pharmaceuticals. PMID:19286283

  11. Sorption of non-polar organic compounds by micro-sized plastic particles in aqueous solution.

    PubMed

    Hüffer, Thorsten; Hofmann, Thilo

    2016-07-01

    The presence of microscale polymer particles (i.e., microplastics) in the environment has become a major concern in recent years. Sorption of organic compounds by microplastics may affect the phase distribution within both sediments and aqueous phases. To investigate this process, isotherms were determined for the sorption of seven aliphatic and aromatic organic probe sorbates by four polymers with different physico-chemical properties. Sorption increased in the order polyamide < polyethylene < polyvinylchloride < polystyrene. This order does not reflect the particle sizes of the investigated microplastics within the aqueous dispersions, indicating the influence of additional factors (e.g., π-π-interactions) on the sorption of aromatic compounds by polystyrene. Linear isotherms by polyethylene suggested that sorbate uptake was due to absorption into the bulk polymer. In contrast, non-linear isotherms for sorption by PS, PA, and PVC suggest a predominance of adsorption onto the polymer surface, which is supported by the best fit of these isotherms using the Polanyi-Manes model. A strong relationship between the sorption coefficients of the microplastics and the hydrophobicity of the sorbates suggests that hydrophobic interactions are of major importance. PMID:27086075

  12. Fluorescence in situ hybridization and spectral imaging analysisof human oocytes and first polar bodies

    SciTech Connect

    Weier, Heinz-Ulli G.; Weier, Jingly F.; Oter Renom, Maria; Zheng,Xuezhong; Colls, Pere; Nureddin, Aida; Pham, Chau D.; Chu, Lisa W.; Racowsky, Catherine; Munne, Santiago

    2004-10-06

    We investigated the frequencies of abnormalities involving either chromosome 1, 16, 18 or 21 in failed-fertilized human oocytes.While abnormalities involving chromosome 16 showed an age-dependant increase, results for the other chromosomes did not show statistically significant differences between the three age groups <35 yrs, 35-39 yrs, and >39 yrs. The scoring of four chromosomes is likely to underestimate the true rate of aneuploid cells. Thus, for a pilot study investigating a more comprehensive analysis of oocytes and their corresponding first polar bodies (1PBs), we developed a novel 8-probe chromosome enumeration scheme using FISH and SIm.

  13. A stereo-compound hybrid microscope for combined intracellular and optical recording of invertebrate neural network activity.

    PubMed

    Frost, William N; Wang, Jean; Brandon, Christopher J

    2007-05-15

    Optical recording studies of invertebrate neural networks with voltage-sensitive dyes seldom employ conventional intracellular electrodes. This may in part be due to the traditional reliance on compound microscopes for such work. While such microscopes have high light-gathering power, they do not provide depth of field, making working with sharp electrodes difficult. Here we describe a hybrid microscope design, with switchable compound and stereo objectives, that eases the use of conventional intracellular electrodes in optical recording experiments. We use it, in combination with a voltage-sensitive dye and photodiode array, to identify neurons participating in the swim motor program of the marine mollusk Tritonia. This microscope design should be applicable to optical recording studies in many preparations. PMID:17306887

  14. Electronic and optical properties of (U,Th)O2 compound from screened hybrid density functional studies

    NASA Astrophysics Data System (ADS)

    Mo, Chongjie; Yang, Yu; Kang, Wei; Zhang, Ping

    2016-04-01

    The electronic structure and optical properties for the (U,Th)O2 compound are systematically studied by employing the Heyd-Scuseria-Ernzerh method (HSE) of screened hybrid density functional. The electronic band gap of (U,Th)O2 is predicted to be 3.06 eV, in the middle of the values of UO2 and ThO2. Based on wavefunction analysis, we conclude (U,Th)O2 to be a Mott insulator in its ground state. The frequency dependent dielectric functions and optical properties are then calculated and compared with those of ThO2 and UO2. At the visible light frequency range, the adsorption coefficients for ThO2, UO2 and (U,Th)O2 are totally different, which gives an accessible method to predict the proportion of U atoms in an arbitrary unknown (U,Th)O2 compounds from the adsorption spectrum of visible lights.

  15. Development of the performance reference compound approach for the calibration of "polar organic chemical integrative sampler" (POCIS).

    PubMed

    Belles, Angel; Tapie, Nathalie; Pardon, Patrick; Budzinski, Hélène

    2014-02-01

    The purpose of the Water Framework Directive is to ensure the quality of the natural water across Europe. In this context, passive samplers have shown interesting capacities for the monitoring of contaminants in aqueous ecosystems. They allow the measurement of time-weighted average concentrations, overcoming many drawbacks of the spot-sampling techniques known to be expensive and time consuming. However, application of passive samplers such as polar organic chemical integrative samplers (POCIS) for the monitoring of hydrophilic contaminants requires calibration to define compound sampling rates; key parameters to deduce the pollutant water concentrations from the amounts of pollutants accumulated by the device. Unfortunately, sampling rates are influenced by a range of environmental factors; in that respect, a question remains: is it not evident to know to what extent the sampling rates obtained in laboratory experiments can be used in field conditions? The problem can be solved for hydrophobic samplers by using performance reference compounds (PRCs), and an ongoing challenge for POCIS is focused on the improvement of the quantitative aspect of this family of samplers. In this study, potential PRCs have been selected during a specific experiment and their performance was tested in the laboratory under two hydrodynamic conditions. Results revealed a good proportionality between elimination rates of PRCs and sampling rates of chemicals. Afterwards, the application of the approach under environmental conditions was assessed by deploying POCIS in the Arcachon Bay (France) where POCIS-PRC-derived water concentrations appear to be close to the simultaneous grab-sampling results. PMID:23978936

  16. A novel stir bar sorptive extraction coating based on monolithic material for apolar, polar organic compounds and heavy metal ions.

    PubMed

    Huang, Xiaojia; Qiu, Ningning; Yuan, Dongxing; Huang, Benli

    2009-04-15

    In this study, a novel stir bar sorptive extraction (SBSE) based on monolithic material (SBSEM) was prepared. The monolithic material was obtained by in situ copolymerization of vinylpyrrolidone and divinylbenzene in the presence of a porogen solvent containing cyclohexanol and 1-dodecanol with azobisisobutyronitrile as initiator. The influences of polymerization conditions on the extraction efficiencies were investigated, using phenol and p-nitrophenol as detected solutes. The monolithic material was characterized by various techniques, such as elemental analysis, scanning electron microscopy, mercury intrusion porosimetry, infrared spectroscopy. Polycyclic aromatic hydrocarbons were used to investigate the extraction efficiencies of SBSEM for apolar analytes. Hormones, aromatic amines and phenols were selected as test analytes to investigate the extraction efficiencies of SBSEM for weakly and strongly polar compounds. The results showed that the new SBSEM could enrich the above-mentioned organic compounds effectively. It is worthy to mention that the SBSEM can enrich some heavy metal ions, such as Cu(2+), Pb(2+), Cr(3+) and Cd(2+), through coordination adsorption. To our best knowledge, that is the first to use SBSE to enrich heavy metal ions. PMID:19174210

  17. Feasibility of analysis of polar compounds by high performance liquid chromatography with Fourier transform infrared spectroscopic detection

    SciTech Connect

    Amateis, P.G.

    1984-01-01

    High performance liquid chromatographic separations employing on-line flow cell Fourier transform infrared spectroscopic detection were developed for polar compounds including phenols, alcohols, amines and azaarenes. Detection by FTIR gave information concerning hydrogen bonding and solvent effects occurring during the separations in addition to giving structural information about eluted species to aid in identification. Both analytical size and microbore normal phase columns were employed. Such experimental considerations as column overload, injected minimum detectable quantities, the use of analytical vs. microbore columns and flow cell pathlength were examined. The developed HPLC-FTIR systems were applied to the analysis of several coal liquefaction samples for heteroatom content. Confirmatory and additional information concerning the samples were provided by field ionization mass spectrometry, gas chromatography/mass spectrometry and reversed phase liquid chromatography employing UV detection. An equation relating reversed phase retention times to structural parameters was developed and applied to the analysis of the coal-derived samples. Two process solvents were found to contain primarily alkyl-substituted phenols in addition to azaarenes such as pyridine and quinoline. Some non-distillable coal-derived samples were found to contain azaarenes such as alkyl quinolines. Evidence was also found concerning the presence of hydroxy-pyridine type compounds and the incorporation of process solvent molecules into the coal structure during liquefaction.

  18. Two hybrid compounds constructed from Ni-tris(imidazolyl) complexes and Keggin clusters: Syntheses, structures and electrochemical properties

    NASA Astrophysics Data System (ADS)

    Zhang, Zhuanfang; Sun, Xiaojun; Ma, Huiyuan; Pang, Haijun; Li, Shaobin; Zhao, Chunyan

    2016-07-01

    By introducing different polyoxotungstates into the Ni-tib (tib = 1, 3, 5-tris (1-imidazolyl)benzene) system, two new polyoxometalate-based inorganic-organic hybrids with distinct architectures, [Ni(Htib)4][PW12O40]2 (1) and [Nitib]2(H2O)4](GeW12O40)·2H2O (2) have been synthesized under the same hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and characterized by infrared spectra (IR), elemental analyses, powder X-ray diffraction (PXRD) patterns and thermogravimetic (TG) analyses. Structural analyses show that compound 1 is a dimer, in which two neighboring mono-connected [PW12O40]3- (PW12) clusters are linked together by a [Ni(Htib)4] complex cation. In contrast to compound 1, compound 2 presents a 2D grid layer formed by bi-connected [GeW12O40]4- (GeW12) clusters and [Ni2(H2O)4(tib)2] complex cations, and the adjacent layers are further linked together by the hydrogen bondings to form a highly opened 3D framework. The distinct structural features of two hybrids suggest that the charge of the Keggin anions should play a key role in the process of assembly. Additionally, the electrochemical properties of compounds 1 and 2 have been investigated, and the results indicated that 1 and 2 have good electrocatalytic activities towards reduction of nitrite and oxidation of ascorbic acid.

  19. Two hybrid compounds constructed from Ni-tris(imidazolyl) complexes and Keggin clusters: Syntheses, structures and electrochemical properties

    NASA Astrophysics Data System (ADS)

    Zhang, Zhuanfang; Sun, Xiaojun; Ma, Huiyuan; Pang, Haijun; Li, Shaobin; Zhao, Chunyan

    2016-07-01

    By introducing different polyoxotungstates into the Ni-tib (tib = 1, 3, 5-tris (1-imidazolyl)benzene) system, two new polyoxometalate-based inorganic-organic hybrids with distinct architectures, [Ni(Htib)4][PW12O40]2 (1) and [Nitib]2(H2O)4](GeW12O40)·2H2O (2) have been synthesized under the same hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and characterized by infrared spectra (IR), elemental analyses, powder X-ray diffraction (PXRD) patterns and thermogravimetic (TG) analyses. Structural analyses show that compound 1 is a dimer, in which two neighboring mono-connected [PW12O40]3- (PW12) clusters are linked together by a [Ni(Htib)4] complex cation. In contrast to compound 1, compound 2 presents a 2D grid layer formed by bi-connected [GeW12O40]4- (GeW12) clusters and [Ni2(H2O)4(tib)2] complex cations, and the adjacent layers are further linked together by the hydrogen bondings to form a highly opened 3D framework. The distinct structural features of two hybrids suggest that the charge of the Keggin anions should play a key role in the process of assembly. Additionally, the electrochemical properties of compounds 1 and 2 have been investigated, and the results indicated that 1 and 2 have good electrocatalytic activities towards reduction of nitrite and oxidation of ascorbic acid.

  20. Sorption / desorption hysteresis of non-polar organic compounds in carbonaceous materials

    NASA Astrophysics Data System (ADS)

    Wang, G.; Kleineidam, S.; Grathwohl, P.

    2003-04-01

    Natural and thermally-altered carbonaceous materials (coals, charcoal, cokes) are nowadays found in many soil and sediment samples due to anthropogenic impact (e.g. industrial activities, traffic) to the natural environment. The sorption -- desorption characteristics of hydrophobic organic compounds on that type of geosorbents play an important role in contaminant fate and transport and are yet not precisely known. Contaminant transport and bioavailibility models often assume complete sorption reversibility. In this study, a series of desorption steps using the ASE (accelerated solvent extractor) with water at different temperatures were carried out to determine the desorption enthalpy and to study hysteresis phenomena. The initial natural loading of PAHs onto the geosorbents was determined by solvent extraction (acetone and toluene). The background loading is in the order of 0.8 mg kg-1 -- 102 mg kg-1 for the natural coals and in the order of 0.16 mg kg-1 -- 10 mg kg-1 for the thermally altered coals. The results are compared to kinetic and equilibrium data from laboratory experiments on sorptive uptake of the phenanthrene onto the same carbonaceous samples.

  1. Generation regimes of bidirectional hybridly mode-locked ultrashort pulse erbium-doped all-fiber ring laser with a distributed polarizer.

    PubMed

    Krylov, Alexander A; Chernykh, Dmitriy S; Arutyunyan, Natalia R; Grebenyukov, Vyacheslav V; Pozharov, Anatoly S; Obraztsova, Elena D

    2016-05-20

    We report on the stable picosecond and femtosecond pulse generation from the bidirectional erbium-doped all-fiber ring laser hybridly mode-locked with a coaction of a single-walled carbon nanotube-based saturable absorber and nonlinear polarization evolution that was introduced through the insertion of the short-segment polarizing fiber. Depending on the total intracavity dispersion value, the laser emits conservative solitons, transform-limited Gaussian pulses, or highly chirped stretched pulses with almost 20 nm wide parabolic spectrum in both clockwise (CW) and counterclockwise (CCW) directions of the ring. Owing to the polarizing action in the cavity, we have demonstrated for the first time, to the best of our knowledge, an efficient tuning of soliton pulse characteristics for both CW and CCW channels via an appropriate polarization control. We believe that the bidirectional laser presented may be highly promising for gyroscopic and other dual-channel applications. PMID:27411151

  2. Highly active and stable hydrogen evolution electrocatalysts based on molybdenum compounds on carbon nanotube-graphene hybrid support.

    PubMed

    Youn, Duck Hyun; Han, Suenghoon; Kim, Jae Young; Kim, Jae Yul; Park, Hunmin; Choi, Sun Hee; Lee, Jae Sung

    2014-05-27

    Highly active and stable electrocatalysts for hydrogen evolution have been developed on the basis of molybdenum compounds (Mo2C, Mo2N, and MoS2) on carbon nanotube (CNT)-graphene hybrid support via a modified urea-glass route. By a simple modification of synthetic variables, the final phases are easily controlled from carbide, nitride to sulfide with homogeneous dispersion of nanocrystals on the CNT-graphene support. Among the prepared catalysts, Mo2C/CNT-graphene shows the highest activity for hydrogen evolution reaction with a small onset overpotential of 62 mV and Tafel slope of 58 mV/dec as well as an excellent stability in acid media. Such enhanced catalytic activity may originate from its low hydrogen binding energy and high conductivity. Moreover, the CNT-graphene hybrid support plays crucial roles to enhance the activity of molybdenum compounds by alleviating aggregation of the nanocrystals, providing a large area to contact with electrolyte, and facilitating the electron transfer. PMID:24787540

  3. Oxygen indicator composed of an organic/inorganic hybrid compound of methylene blue, reductant, surfactant and saponite.

    PubMed

    Sumitani, Makoto; Takagi, Shinsuke; Tanamura, Yoshihiko; Inoue, Haruo

    2004-08-01

    An organic/inorganic hybrid compound consisting of methylene blue, a cationic surfactant and a reductant intercalated into saponite was found to serve as an oxygen indicator that changes color in the presence of oxygen. A mixture of a blue colored dye, methylene blue, a reductant in the form of ascorbic acid or reducing sugar, and cetyltrimethylammonium ion intercalated into synthetic saponite became colorless in an atmosphere having an oxygen concentration of less than 0.1 vol%, and then returned to its blue color as a result of subsequent exposure to air. An oxygen indicator, in the form of a thin film coated on paper prepared by adding a pigment, phloxine B, to the above organic/inorganic hybrid compound, exhibited a pink color at oxygen concentrations of less than 0.1 vol%, and a blue color at oxygen concentrations of higher than 0.5 vol%. In addition, this oxygen indicator exhibited superior photo-fading resistance and storage stability compared with indicators using only methylene blue as the functional dye. PMID:15352503

  4. A reductionist mechanistic model for bioconcentration of neutral and weakly polar organic compounds in fish.

    PubMed

    Kuo, Dave T F; Di Toro, Dominic M

    2013-09-01

    The bioconcentration factor (BCF) of neutral and weakly polar organic chemicals in fish is modeled using independently calibrated models of chemical partitioning (freely dissolved fraction of chemical in the aqueous phase [φsys ] and wet-weight fish-water partition coefficient [KFW ]), respiratory exchange (respiratory update rate constant [k1 ], and respiratory elimination rate constant [k2  = k1 /KFW ]), and biotransformation (whole-body biotransformation rate constant [kM ]) as BCF = φsys KFW /(1 + kM /k2 ). Existing k1 models tend to overestimate for chemicals with log KOW  < 3.5, which constituted 30% to 50% of the examined chemicals. A revised k1 model covering a wider log KOW range (0-8.5) is presented k1  = (5.46 × 10(-6) MW + 0.261/KOW )(-1) , where MW is the molecular weight. The biotransformation rate constant kM is modeled using biota internal partitioning and Abraham parameters as reactivity descriptors. The reductionist model was tested using 3 different BCF data sets (US Environmental Protection Agency's Estimation Programs Interface [EPI], n = 548; Hertfordshire, n = 210; Arnot-Gobas, n = 1855) and compared with the following 3 state-of-the-art models: 1) the EPI Suite BCFBAF module, 2) the European Commision's Computer Assisted Evaluation of industrial chemical Substances According to Regulations (CAESAR), and 3) the EPI/Arnot mechanistic kinetic model. The reductionist model performed comparably with the alternative models (root mean square errors [RMSEs] = 0.72-0.77), with only 5 fitting parameters and no training against experimental BCFs. Respiratory elimination and biotransformation dominate the total depuration (i.e., [k2  + kM ]/kT  ≥ 0.8) for approximately 98% of the data entries, thus validating the reductionist approximation. Mechanistic models provide greater insights into bioaccumulation and are more sensitive to biological variation. All three BCF data sets and relevant

  5. Study on the Keggin zinctungstates based hybrid compound with like DNA spiral chain

    NASA Astrophysics Data System (ADS)

    Li, Liang; Sha, Jing-Quan; Zong, Xi-Ming; Liu, Cui-Juan; Zhang, Qian-Nan; Wang, Dong-Wen; Yang, Xiao-Ning; Wang, Yu

    2014-05-01

    A new compound based on polyoxometalates (POMs) and the quinolone antibacterial pipemidic acid (HPPA), {[Zn(HPPA)2H2O]2[H2ZnW12O40]}ṡ9H2O (1), was hydrothermally synthesized and characterized by elemental analyses, IR and XPRD. Single-crystal X-ray diffraction analysis reveals that the [ clusters and Zn-HPPA complexes constructed both right- and left-double-stranded like DNA helical chains in the title compound, and these helical chains are further connected together forming the fascinating quadruple-stranded helices via sharing the ZnW12 clusters. Note that the compound 1 represents the first example of zinctungstate POMs modified by antibacterial drugs. In addition, the antibacterial properties of the compound 1 were investigated.

  6. A 14 × 14 μm2 footprint polarization-encoded quantum controlled-NOT gate based on hybrid waveguide

    NASA Astrophysics Data System (ADS)

    Wang, S. M.; Cheng, Q. Q.; Gong, Y. X.; Xu, P.; Sun, C.; Li, L.; Li, T.; Zhu, S. N.

    2016-05-01

    Photonic quantum information processing system has been widely used in communication, metrology and lithography. The recent emphasis on the miniaturized photonic platform is thus motivated by the urgent need for realizing large-scale information processing and computing. Although the integrated quantum logic gates and quantum algorithms based on path encoding have been successfully demonstrated, the technology for handling another commonly used polarization-encoded qubits has yet to be fully developed. Here, we show the implementation of a polarization-dependent beam-splitter in the hybrid waveguide system. With precisely design, the polarization-encoded controlled-NOT gate can be implemented using only single such polarization-dependent beam-splitter with the significant size reduction of the overall device footprint to 14 × 14 μm2. The experimental demonstration of the highly integrated controlled-NOT gate sets the stage to develop large-scale quantum information processing system. Our hybrid design also establishes the new capabilities in controlling the polarization modes in integrated photonic circuits.

  7. A 14 × 14 μm2 footprint polarization-encoded quantum controlled-NOT gate based on hybrid waveguide

    PubMed Central

    Wang, S. M.; Cheng, Q. Q.; Gong, Y. X.; Xu, P.; Sun, C.; Li, L.; Li, T.; Zhu, S. N.

    2016-01-01

    Photonic quantum information processing system has been widely used in communication, metrology and lithography. The recent emphasis on the miniaturized photonic platform is thus motivated by the urgent need for realizing large-scale information processing and computing. Although the integrated quantum logic gates and quantum algorithms based on path encoding have been successfully demonstrated, the technology for handling another commonly used polarization-encoded qubits has yet to be fully developed. Here, we show the implementation of a polarization-dependent beam-splitter in the hybrid waveguide system. With precisely design, the polarization-encoded controlled-NOT gate can be implemented using only single such polarization-dependent beam-splitter with the significant size reduction of the overall device footprint to 14 × 14 μm2. The experimental demonstration of the highly integrated controlled-NOT gate sets the stage to develop large-scale quantum information processing system. Our hybrid design also establishes the new capabilities in controlling the polarization modes in integrated photonic circuits. PMID:27142992

  8. A 14 × 14 μm(2) footprint polarization-encoded quantum controlled-NOT gate based on hybrid waveguide.

    PubMed

    Wang, S M; Cheng, Q Q; Gong, Y X; Xu, P; Sun, C; Li, L; Li, T; Zhu, S N

    2016-01-01

    Photonic quantum information processing system has been widely used in communication, metrology and lithography. The recent emphasis on the miniaturized photonic platform is thus motivated by the urgent need for realizing large-scale information processing and computing. Although the integrated quantum logic gates and quantum algorithms based on path encoding have been successfully demonstrated, the technology for handling another commonly used polarization-encoded qubits has yet to be fully developed. Here, we show the implementation of a polarization-dependent beam-splitter in the hybrid waveguide system. With precisely design, the polarization-encoded controlled-NOT gate can be implemented using only single such polarization-dependent beam-splitter with the significant size reduction of the overall device footprint to 14 × 14 μm(2). The experimental demonstration of the highly integrated controlled-NOT gate sets the stage to develop large-scale quantum information processing system. Our hybrid design also establishes the new capabilities in controlling the polarization modes in integrated photonic circuits. PMID:27142992

  9. Hybrid QM/MM study of FMO complex with polarized protein-specific charge

    NASA Astrophysics Data System (ADS)

    Jia, Xiangyu; Mei, Ye; Zhang, John Z. H.; Mo, Yan

    2015-11-01

    The Fenna-Matthews-Olson (FMO) light-harvesting complex is now one of the primary model systems for the study of excitation energy transfer (EET). However, the mechanism of the EET in this system is still controversial. In this work, molecular dynamics simulations and the electrostatic-embedding quantum-mechanics/molecular-mechanics single-point calculations have been employed to predict the energy transfer pathways utilizing the polarized protein-specific charge (PPC), which provides a more realistic description of Coulomb interaction potential in the protein than conventional mean-field charge scheme. The recently discovered eighth pigment has also been included in this study. Comparing with the conventional mean-field charges, more stable structures of FMO complex were found under PPC scheme during molecular dynamic simulation. Based on the electronic structure calculations, an exciton model was constructed to consider the couplings during excitation. The results show that pigments 3 and 4 dominate the lowest exciton levels whereas the highest exciton level are mainly constituted of pigments 1 and 6. This observation agrees well with the assumption based on the spatial distribution of the pigments. Moreover, the obtained spectral density in this study gives a reliable description of the diverse local environment embedding each pigment.

  10. High-speed guided-wave electro-optic modulators and polarization converters in III-V compound semiconductors

    NASA Astrophysics Data System (ADS)

    Rahmatian, Farnoosh

    In the last few decades, the need for electronic communication has increased by several orders of magnitude. Due to the rapid growth of the demand for transmission bandwidth, development of very high-speed communication systems is crucial. This thesis describes integrated-optic electro-optic modulators using travelling-wave electrodes in compound semiconductors for ultra-high-speed guided-wave optical communications. Both Mach-Zehnder (MZ) interferometric modulators and polarization converters (PC) have been studied with particular emphasis on the latter ones. Slow-wave travelling-wave electrodes in compound semiconductors have previously been proposed and demonstrated. Here, a study of slow-wave, travelling-wave electrodes on compound semiconductors has been performed in order to significantly improve their use in ultra-wide-band guided-wave electro-optic devices. The most important factors limiting the high frequency performance of such devices, in general, are the microwave-lightwave velocity mismatch and the microwave loss on the electrodes. Based on the deeper understanding acquired through our study, we have designed, fabricated, and tested low-loss, slow-wave, travelling-wave electrodes on semi- insulating GaAs (SI-GaAs) and AlGaAs/GaAs substrates. Microwave-to-lightwave velocity matching within 1% was achieved using slow-wave coplanar strip electrodes; many of the electrodes had effective microwave indices in the range 3.3 to 3.4 (measured at frequencies up to 40 GHz). For the electrodes fabricated on SI-GaAs substrates, microwave losses of 0.22 Np/cm and 0.34 Np/cm (average values at 40 GHz) were measured for the slow-wave coplanar strip and the slow-wave coplanar waveguide electrodes, respectively. For the electrodes fabricated on the AlGaAs/GaAs substrates containing the modulators, the corresponding losses were, on average, 0.17 Np/cm higher at 40 GHz. For the first time, ultra-wide-band polarization converters using slow-wave electrodes have been

  11. Tuning the electronic hybridization in the heavy fermion cage compound YbFe2Zn20 with Cd doping

    NASA Astrophysics Data System (ADS)

    Cabrera-Baez, M.; Ribeiro, R. A.; Avila, M. A.

    2016-09-01

    The tuning of the electronic properties of heavy fermion compounds by chemical substitution provides excellent opportunities for further understanding the physics of hybridized ions in crystal lattices. Here we present an investigation on the effects of Cd doping in flux-grown single crystals of the complex intermetallic cage compound YbFe2Zn20, which has been described as a heavy fermion with a Sommerfeld coefficient of 535 mJ mol‑1 · K‑2. The substitution of Cd for Zn disturbs the system by expanding the unit cell and, in this case, the size of the Zn cages that surround the Yb and Fe. With an increasing amount of Cd, the hybridization between the Yb 4f electrons and the conduction electrons is weakened, as shown by a decrease in the Sommerfeld coefficient, which should be accompanied by a valence shift of the Yb3+ due to the negative chemical pressure effect. This scenario is also supported by the low temperature DC magnetic susceptibility, which is gradually suppressed and shows an increment of the Kondo temperature, based on a shift to higher temperatures of the characteristic broad susceptibility peak. Furthermore, the DC resistivity decreases with the isoelectronic substitution of Cd for Zn, contrary to expectations in an increasingly disordered system, and implying that the valence shift is not related to charge carrier doping. The combined results demonstrate the excellent complementarity between positive physical pressure and negative chemical pressure, and point to a rich playground for exploring the physics and chemistry of strongly correlated electron systems in the general family of Zn20 compounds, despite their structural complexity.

  12. Tuning the electronic hybridization in the heavy fermion cage compound YbFe2Zn20 with Cd doping.

    PubMed

    Cabrera-Baez, M; Ribeiro, R A; Avila, M A

    2016-09-21

    The tuning of the electronic properties of heavy fermion compounds by chemical substitution provides excellent opportunities for further understanding the physics of hybridized ions in crystal lattices. Here we present an investigation on the effects of Cd doping in flux-grown single crystals of the complex intermetallic cage compound YbFe2Zn20, which has been described as a heavy fermion with a Sommerfeld coefficient of 535 mJ mol(-1) · K(-2). The substitution of Cd for Zn disturbs the system by expanding the unit cell and, in this case, the size of the Zn cages that surround the Yb and Fe. With an increasing amount of Cd, the hybridization between the Yb 4f electrons and the conduction electrons is weakened, as shown by a decrease in the Sommerfeld coefficient, which should be accompanied by a valence shift of the Yb(3+) due to the negative chemical pressure effect. This scenario is also supported by the low temperature DC magnetic susceptibility, which is gradually suppressed and shows an increment of the Kondo temperature, based on a shift to higher temperatures of the characteristic broad susceptibility peak. Furthermore, the DC resistivity decreases with the isoelectronic substitution of Cd for Zn, contrary to expectations in an increasingly disordered system, and implying that the valence shift is not related to charge carrier doping. The combined results demonstrate the excellent complementarity between positive physical pressure and negative chemical pressure, and point to a rich playground for exploring the physics and chemistry of strongly correlated electron systems in the general family of Zn20 compounds, despite their structural complexity. PMID:27419654

  13. Open Field Study of Some Zea mays Hybrids, Lipid Compounds and Fumonisins Accumulation

    PubMed Central

    Giorni, Paola; Dall’Asta, Chiara; Reverberi, Massimo; Scala, Valeria; Ludovici, Matteo; Cirlini, Martina; Galaverna, Gianni; Fanelli, Corrado; Battilani, Paola

    2015-01-01

    Lipid molecules are increasingly recognized as signals exchanged by organisms interacting in pathogenic and/or symbiotic ways. Some classes of lipids actively determine the fate of the interactions. Host cuticle/cell wall/membrane components such as sphingolipids and oxylipins may contribute to determining the fate of host–pathogen interactions. In the present field study, we considered the relationship between specific sphingolipids and oxylipins of different hybrids of Zea mays and fumonisin by F. verticillioides, sampling ears at different growth stages from early dough to fully ripe. The amount of total and free fumonisin differed significantly between hybrids and increased significantly with maize ripening. Oxylipins and phytoceramides changed significantly within the hybrids and decreased with kernel maturation, starting from physiological maturity. Although the correlation between fumonisin accumulation and plant lipid profile is certain, the data collected so far cannot define a cause-effect relationship but open up new perspectives. Therefore, the question—“Does fumonisin alter plant lipidome or does plant lipidome modulate fumonisin accumulation?”—is still open. PMID:26378580

  14. Open Field Study of Some Zea mays Hybrids, Lipid Compounds and Fumonisins Accumulation.

    PubMed

    Giorni, Paola; Dall'Asta, Chiara; Reverberi, Massimo; Scala, Valeria; Ludovici, Matteo; Cirlini, Martina; Galaverna, Gianni; Fanelli, Corrado; Battilani, Paola

    2015-09-01

    Lipid molecules are increasingly recognized as signals exchanged by organisms interacting in pathogenic and/or symbiotic ways. Some classes of lipids actively determine the fate of the interactions. Host cuticle/cell wall/membrane components such as sphingolipids and oxylipins may contribute to determining the fate of host-pathogen interactions. In the present field study, we considered the relationship between specific sphingolipids and oxylipins of different hybrids of Zea mays and fumonisin by F. verticillioides, sampling ears at different growth stages from early dough to fully ripe. The amount of total and free fumonisin differed significantly between hybrids and increased significantly with maize ripening. Oxylipins and phytoceramides changed significantly within the hybrids and decreased with kernel maturation, starting from physiological maturity. Although the correlation between fumonisin accumulation and plant lipid profile is certain, the data collected so far cannot define a cause-effect relationship but open up new perspectives. Therefore, the question-"Does fumonisin alter plant lipidome or does plant lipidome modulate fumonisin accumulation?"-is still open. PMID:26378580

  15. Effects of alpha beam on the parametric decay of a parallel propagating circularly polarized Alfven wave: Hybrid simulations

    SciTech Connect

    Gao, Xinliang; Lu, Quanming; Tao, Xin; Hao, Yufei; Wang, Shui

    2013-09-15

    Alfven waves with a finite amplitude are found to be unstable to a parametric decay in low beta plasmas. In this paper, the parametric decay of a circularly polarized Alfven wave in a proton-electron-alpha plasma system is investigated with one-dimensional (1-D) hybrid simulations. In cases without alpha particles, with the increase of the wave number of the pump Alfven wave, the growth rate of the decay instability increases and the saturation amplitude of the density fluctuations slightly decrease. However, when alpha particles with a sufficiently large bulk velocity along the ambient magnetic field are included, at a definite range of the wave numbers of the pump wave, both the growth rate and the saturation amplitude of the parametric decay become much smaller and the parametric decay is heavily suppressed. At these wave numbers, the resonant condition between the alpha particles and the daughter Alfven waves is satisfied, therefore, their resonant interactions might play an important role in the suppression of the parametric decay instability.

  16. Effects of alpha beam on the parametric decay of a parallel propagating circularly polarized Alfven wave: Hybrid simulations

    NASA Astrophysics Data System (ADS)

    Gao, Xinliang; Lu, Quanming; Tao, Xin; Hao, Yufei; Wang, Shui

    2013-09-01

    Alfven waves with a finite amplitude are found to be unstable to a parametric decay in low beta plasmas. In this paper, the parametric decay of a circularly polarized Alfven wave in a proton-electron-alpha plasma system is investigated with one-dimensional (1-D) hybrid simulations. In cases without alpha particles, with the increase of the wave number of the pump Alfven wave, the growth rate of the decay instability increases and the saturation amplitude of the density fluctuations slightly decrease. However, when alpha particles with a sufficiently large bulk velocity along the ambient magnetic field are included, at a definite range of the wave numbers of the pump wave, both the growth rate and the saturation amplitude of the parametric decay become much smaller and the parametric decay is heavily suppressed. At these wave numbers, the resonant condition between the alpha particles and the daughter Alfven waves is satisfied, therefore, their resonant interactions might play an important role in the suppression of the parametric decay instability.

  17. A 3D hybrid praseodymium-antimony-oxochloride compound: single-crystal-to-single-crystal transformation and photocatalytic properties.

    PubMed

    Zou, Guo-Dong; Zhang, Gui-Gang; Hu, Bing; Li, Jian-Rong; Feng, Mei-Ling; Wang, Xin-Chen; Huang, Xiao-Ying

    2013-11-01

    A 3D organic-inorganic hybrid compound, (2-MepyH)3[{Fe(1,10-phen)3}3][{Pr4Sb12O18(OH)Cl(11.5)}(TDC)(4.5)({Pr4Sb12O18(OH)Cl(9.5)} Cl)]·3(2-Mepy)·28H2O (1; 2-Mepy=2-methylpyridine, 1,10-phen=1,10-phenanthroline, H2TDC=thiophene-2,5-dicarboxylic acid), was hydrothermally synthesized and structurally characterized. Unusually, two kinds of high-nuclearity clusters, namely [(Pr4Sb12O18(OH)Cl11)(COO)5](5-) and [(Pr4Sb12O18(OH)Cl9)Cl(COO)5](4-), coexist in the structure of compound 1; two of the latter clusters are doubly bridged by two μ2-Cl(-) moieties to form a new centrosymmetric dimeric cluster. An unprecedented spontaneous and reversible single-crystal-to-single-crystal transformation was observed, which simultaneously involved a notable organic-ligand movement between the metal ions and an alteration of the bridging ion in the dimeric cluster, induced by guest-release/re-adsorption, thereby giving rise to the interconversion between compound 1 and the compound (2-MepyH)3[{Fe(1,10-phen)3}3][{Pr4Sb12O18(OH)Cl(11.5)}(TDC)4({Pr4Sb12O18Cl(10.5)(TDC)(0.5)(H2O)(1.5)}O(0.5))]·25H2O (1'). The mechanism of this transformation has also been discussed in great detail. Photocatalytic H2-evolution activity was observed for compound 1' under UV light with Pt as a co-catalyst and MeOH as a sacrificial electron donor. PMID:24114981

  18. Hybrid Hamiltonian and Green's Function Approach for Studying Native Point Defect Levels in Semiconductor Compounds and Superlattices

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Srini; Van Orden, Derek; Yu, Zhi-Gang

    2016-04-01

    We have developed a hybrid method that can be applied to study isolated defects in semiconductor compounds and superlattices. The method is a combination of (1) a long-range tight-binding (TB) Hamiltonian, (2) a first-principles Hamiltonian, and (3) a Green's function (GF) formalism. The calculation of the GF requires accurate energy band structure, wave functions, and defect potentials. The TB Hamiltonian with sp 3 orbitals basis ensures accurate band gaps and band masses while providing the functional form for the wave functions. We calculated the band gaps of InAs/GaSb and InAs/InAsSb strained-layer superlattices and found them to agree well with measurements. The change in potentials caused by native point defects (NPDs) was obtained from a first-principles method using Spanish Initiative for Electronic Simulations with Thousands of Atoms, which also uses sp 3 basis. We describe the method of calculating NPD energy levels in compounds and superlattices, obtain some defect levels in GaAs, InAs, InSb, and GaSb compounds, and provide details of the NPD-level calculations.

  19. Hybrid Hamiltonian and Green's Function Approach for Studying Native Point Defect Levels in Semiconductor Compounds and Superlattices

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Srini; Van Orden, Derek; Yu, Zhi-Gang

    2016-09-01

    We have developed a hybrid method that can be applied to study isolated defects in semiconductor compounds and superlattices. The method is a combination of (1) a long-range tight-binding (TB) Hamiltonian, (2) a first-principles Hamiltonian, and (3) a Green's function (GF) formalism. The calculation of the GF requires accurate energy band structure, wave functions, and defect potentials. The TB Hamiltonian with sp 3 orbitals basis ensures accurate band gaps and band masses while providing the functional form for the wave functions. We calculated the band gaps of InAs/GaSb and InAs/InAsSb strained-layer superlattices and found them to agree well with measurements. The change in potentials caused by native point defects (NPDs) was obtained from a first-principles method using Spanish Initiative for Electronic Simulations with Thousands of Atoms, which also uses sp 3 basis. We describe the method of calculating NPD energy levels in compounds and superlattices, obtain some defect levels in GaAs, InAs, InSb, and GaSb compounds, and provide details of the NPD-level calculations.

  20. Enantiomer separation of acidic chiral compounds on a quinine-silica/zirconia hybrid monolith by capillary electrochromatography.

    PubMed

    Tran, Le Ngoc; Park, Jung Hag

    2015-05-29

    A weak anion-exchanger chiral selector, quinine-incorporated silica/zirconia hybrid monolithic (QUI-S/ZHM) capillary column was prepared by sol-gel technology. The performance of the QUI-S/ZHM column was investigated for enantioresolution of a set of acidic chiral drugs and dinitrobenzoyl (DNB)-amino acids by capillary electrochromatography in aqueous organic mobile phases composed of acetonitrile (ACN) and triethylammonium acetate (TEAA) buffer. Effects of several parameters including the ACN content, concentration and pH of the mobile phase on the chiral separation were examined. Baseline resolutions of all the compounds were obtained in the mobile phase consisting of 70:30 ACN/TEAA (10mM, pH 6) under applied voltage of -10kV at 25°C within 20min. PMID:25892638

  1. Polyhalogenated compounds (PCBs, chlordanes, HCB and BFRs) in four polar bears (Ursus maritimus) that swam malnourished from East Greenland to Iceland.

    PubMed

    Vetter, Walter; Gall, Vanessa; Skírnisson, Karl

    2015-11-15

    Levels of organohalogen compounds (PCBs, chlordane, PBB 153, PBDEs, HCB) were determined in adipose tissue, liver, kidney and muscle of four polar bears which swam and/or drifted to Iceland in extremely malnourished condition. Since the colonization in the 9th century polar bears have been repeatedly observed in Iceland. However, in recent years three of the animals have clearly left their natural habitat in poor condition in May or June, i.e. at the end of the major feeding season. The fourth bear is believed to have drifted with melting ice to North-Eastern Iceland in mid-winter. The concentrations of the POPs were within the range or higher than the typical concentrations measured in polar bears from the East Greenland population. In addition to the targeted compounds, we tentatively detected Dechlorane 602 and its potential hydrodechlorinated Cl11-metabolite in all samples. Moreover, a polychlorinated compound which partly co-eluted with PCB 209 was detected in all liver samples but not in adipose tissue, kidney or muscle. The mass spectrum of the potential metabolite did not allow determining its structure. Polar bears are good swimmers and can reach Iceland from the ice edge of East Greenland within a few days. Potential reasons for the swims are briefly discussed. PMID:26172596

  2. An electrogenerated chemiluminescence sensor based on gold nanoparticles@C60 hybrid for the determination of phenolic compounds.

    PubMed

    Lu, Qiyi; Hu, Hongxiang; Wu, Yuanya; Chen, Shihong; Yuan, Dehua; Yuan, Ruo

    2014-10-15

    This paper described a novel strategy for the construction of an electrogenerated chemiluminescence (ECL) sensor based on gold nanoparticles@C60 (AuNPs@C60) hybrid for detecting phenolic compounds. First, C60 was functionalized with l-cysteine. Subsequently, with C60 as the core, gold nanoparticles (AuNPs) are synthesized and grown through an in situ reduction method in the presence of ascorbic acid (AA). The resulted flowerlike AuNPs@C60 nanoparticles were modified onto the glassy carbon electrode to achieve the sensor (AuNPs@C60/GCE). Here, l-cysteine not only can improve the biocompatibility and hydrophilicity of C60 but also can enhance the electrogenerated chemiluminescence (ECL) of peroxydisulfate system. Furthermore, both AuNPs and C60 are also beneficial to the ECL of the peroxydisulfate system. Due to the combination of l-cysteine, AuNPs and C60, the proposed ECL sensor exhibited an excellent analytical performance. Under an optimum condition, the ECL intensity increased linearly with phenolic compounds. The linear ranges of 6.2 × 10(-8)-1.2 × 10(-4)M, 5.0 × 10(-8)-1.1 × 10(-4)M and 5.0 × 10(-8)-1.1 × 10(-4)M were obtained for catechol (CC), hydroquinone (HQ) and p-cresol (PC), respectively, and the detection limits were 2.1 × 10(-8)M, 1.5 × 10(-8)M and 1.7 × 10(-8)M, respectively. The AuNPs@C60 hybrid might hold a new opportunity to develop an ECL sensor. PMID:24836015

  3. Optimal densities of alkali metal atoms in an optically pumped K-Rb hybrid atomic magnetometer considering the spatial distribution of spin polarization.

    PubMed

    Ito, Yosuke; Sato, Daichi; Kamada, Keigo; Kobayashi, Tetsuo

    2016-07-11

    An optically pumped K-Rb hybrid atomic magnetometer can be a useful tool for biomagnetic measurements due to the high spatial homogeneity of its sensor property inside a cell. However, because the property varies depending on the densities of potassium and rubidium atoms, optimization of the densities is essential. In this study, by using the Bloch equations of K and Rb and considering the spatial distribution of the spin polarization, we confirmed that the calculation results of spin polarization behavior are in good agreement with the experimental data. Using our model, we calculated the spatial distribution of the spin polarization and found that the optimal density of K atoms is 3 × 1019 m-3 and the optimal density ratio is nK/nRb ~ 400 to maximize the output signal and enhance spatial homogeneity of the sensor property. PMID:27410815

  4. Hybrid plasmonic gap modes in metal film-coupled dimers and their physical origins revealed by polarization resolved dark field spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Guang-Can; Zhang, Yong-Liang; Lei, Dang Yuan

    2016-03-01

    Plasmonic gap modes sustained by metal film-coupled nanostructures have recently attracted extensive research attention due to flexible control over their spectral response and significantly enhanced field intensities at the particle-film junction. In this work, by adopting an improved dark field spectroscopy methodology - polarization resolved spectral decomposition and colour decoding - we are able to ``visualize'' and distinguish unambiguously the spectral and far field radiation properties of the complex plasmonic gap modes in metal film-coupled nanosphere monomers and dimers. Together with full-wave numerical simulation results, it is found that while the monomer-film system supports two hybridized dipole-like plasmon modes having different oscillating orientations and resonance strengths, the scattering spectrum of the dimer-film system features two additional peaks, one strong yet narrow resonant mode corresponding to a bonding dipolar moment and one hybridized higher order resonant mode, both polarized along the dimer axis. In particular, we demonstrate that the polarization dependent scattering radiation of the film-coupled nanosphere dimer can be used to optically distinguish from monomers and concurrently determine the spatial orientation of the dimer with significantly improved accuracy at the single-particle level, illustrating a simple yet highly sensitive plasmon resonance based nanometrology method.Plasmonic gap modes sustained by metal film-coupled nanostructures have recently attracted extensive research attention due to flexible control over their spectral response and significantly enhanced field intensities at the particle-film junction. In this work, by adopting an improved dark field spectroscopy methodology - polarization resolved spectral decomposition and colour decoding - we are able to ``visualize'' and distinguish unambiguously the spectral and far field radiation properties of the complex plasmonic gap modes in metal film

  5. Weak hybridization and isolated localized magnetic moments in the compounds CeT2Cd20 (T = Ni, Pd)

    NASA Astrophysics Data System (ADS)

    White, B. D.; Yazici, D.; Ho, P.-C.; Kanchanavatee, N.; Pouse, N.; Fang, Y.; Breindel, A. J.; Friedman, A. J.; Maple, M. B.

    2015-08-01

    We report the physical properties of single crystals of the compounds CeT2Cd20 (T = Ni, Pd) that were grown in a molten Cd flux. Large separations of  ˜6.7-6.8 Å between Ce ions favor the localized magnetic moments that are observed in measurements of the magnetization. The strength of the Ruderman-Kittel-Kasuya-Yosida magnetic exchange interaction between the localized moments is severely limited by the large Ce-Ce separations and by weak hybridization between localized Ce 4 f and itinerant electron states. Measurements of electrical resistivity performed down to 0.138 K were unable to observe evidence for the emergence of magnetic order; however, magnetically-ordered ground states with very low transition temperatures are still expected in these compounds despite the isolated nature of the localized magnetic moments. Such a fragile magnetic order could be highly susceptible to tuning via applied pressure, but evidence for the emergence of magnetic order has not been observed so far in our measurements up to 2.5 GPa.

  6. Weak hybridization and isolated localized magnetic moments in the compounds CeT2Cd20 (T = Ni, Pd)

    DOE PAGESBeta

    White, B. D.; Yazici, D.; Ho, P. -C.; Kanchanavatee, N.; Pouse, N.; Fang, Y.; Breindel, A. J.; Friedman, A. J.; Maple, M. B.

    2015-07-20

    Here, we report the physical properties of single crystals of the compounds CeT2Cd20 (T = Ni, Pd) that were grown in a molten Cd flux. Large separations of ~6.7- 6.8 Å between Ce ions favor the localized magnetic moments that are observed in measurements of the magnetization. The strength of the Ruderman-Kittel-Kasuya- Yosida magnetic exchange interaction between the localized moments is severely limited by the large Ce-Ce separations and by weak hybridization between localized Ce 4f and itinerant electron states. Measurements of electrical resistivity performed down to 0.138 K were unable to observe evidence for the emergence of magnetic order;more » however, magnetically-ordered ground states with very low transition temperatures are still expected in these compounds despite the isolated nature of the localized magnetic moments. Such a fragile magnetic order could be highly susceptible to tuning via applied pressure, but evidence for the emergence of magnetic order has not been observed so far in our measurements up to 2.5 GPa.« less

  7. Design, synthesis and evaluation of novel tacrine-multialkoxybenzene hybrids as multi-targeted compounds against Alzheimer's disease.

    PubMed

    Zhang, Chao; Du, Qiao-Yi; Chen, Lang-Di; Wu, Wen-Hao; Liao, Si-Yan; Yu, Li-Hong; Liang, Xin-Tong

    2016-06-30

    A series of benzoates (or phenylacetates or cinnamates) - tacrine hybrids (7a-o) were designed, synthesized and evaluated as multi-potent anti-Alzheimer drug candidates. The screening results showed that most of them exhibited a significant ability to inhibit ChEs, certain selectivity for AChE over BuChE and strong potency inhibitory of self-induced β-amyloid (Aβ) aggregation. All IC50 values of biological activity were at the nanomolar range. Especially, compound 7c displayed the greatest ability to inhibit AChE with an IC50 value of 5.63 nM and the highest selectivity with ratio of BuChE/AChE value of 64.6. Moreover, it also exhibited a potent inhibitory of Aβ aggregation with an IC50 value of 51.81 nM. A Lineweaver-Burk plot and molecular modeling study showed that compound 7c targeted both the CAS and PAS of ChEs. A structure-activity relationship analysis suggested that the electron density of aromatic ring which was linked with tacrine through acetyl group played a significant role in determining the inhibitory activity. PMID:27061983

  8. Weak hybridization and isolated localized magnetic moments in the compounds CeT₂Cd₂₀ (T = Ni, Pd).

    PubMed

    White, B D; Yazici, D; Ho, P-C; Kanchanavatee, N; Pouse, N; Fang, Y; Breindel, A J; Friedman, A J; Maple, M B

    2015-08-12

    We report the physical properties of single crystals of the compounds CeT2Cd20 (T = Ni, Pd) that were grown in a molten Cd flux. Large separations of  ∼6.7-6.8 Å between Ce ions favor the localized magnetic moments that are observed in measurements of the magnetization. The strength of the Ruderman-Kittel-Kasuya-Yosida magnetic exchange interaction between the localized moments is severely limited by the large Ce-Ce separations and by weak hybridization between localized Ce 4 f and itinerant electron states. Measurements of electrical resistivity performed down to 0.138 K were unable to observe evidence for the emergence of magnetic order; however, magnetically-ordered ground states with very low transition temperatures are still expected in these compounds despite the isolated nature of the localized magnetic moments. Such a fragile magnetic order could be highly susceptible to tuning via applied pressure, but evidence for the emergence of magnetic order has not been observed so far in our measurements up to 2.5 GPa. PMID:26189502

  9. Segmentation and quantification of blood vessels for OCT-based micro-angiograms using hybrid shape/intensity compounding

    PubMed Central

    Yousefi, Siavash; Liu, Ting; Wang, Ruikang K.

    2014-01-01

    Optical coherence tomography (OCT) based microangiography is capable of visualizing 3D functional blood vessel networks within microcirculatory tissue beds in vivo. To provide the quantitative information of vasculature from the microangiograms such as vessel diameter and morphology, it is necessary to develop efficient vessel segmentation algorithms. In this paper, we propose to develop a hybrid Hessian/intensity based method to segment and quantify shape and diameter of the blood vessels innervating capillary beds that are imaged by functional OCT in vivo. The proposed method utilizes the multi-scale Hessian filters to segment tubular structures such as blood vessels, but compounded by the intensity-based segmentation method to mitigate the limitations of Hessian filter's sensitivity to the selection of scale parameters. Such compounding segmentation scheme takes the advantage of morphological nature of Hessian filters while correcting for the scale parameter selection by intensity-based segmentation. The proposed algorithm is tested on a wound healing model and its performance of segmentation vessels is quantified by a publicly available manual segmentation dataset. We believe that this method will play an important role in the quantification of micro-angiograms for microcirculation research in ophthalmology and diagnosing retinal eye diseases involved with microcirculation. PMID:25283347

  10. Controlling the number of walls in multi walled carbon nanotubes/alumina hybrid compound via ball milling of precipitate catalyst

    NASA Astrophysics Data System (ADS)

    Nosbi, Norlin; Akil, Hazizan Md

    2015-06-01

    This paper reports the influence of milling time on the structure and properties of the precipitate catalyst of multi walled carbon nanotubes (MWCNT)/alumina hybrid compound, produced through the chemical vapour deposition (CVD) process. For this purpose, light green precipitate consisted of aluminium, nickel(II) nitrate hexahydrate and sodium hydroxide mixture was placed in a planetary mill equipped with alumina vials using alumina balls at 300 rpm rotation speed for various milling time (5-15 h) prior to calcinations and CVD process. The compound was characterized using various techniques. Based on high-resolution transmission electron microscopy analysis, increasing the milling time up to 15 h decreased the diameter of MWCNT from 32.3 to 13.1 nm. It was noticed that the milling time had a significant effect on MWCNT wall thickness, whereby increasing the milling time from 0 to 15 h reduced the number of walls from 29 to 12. It was also interesting to note that the carbon content increased from 23.29 wt.% to 36.37 wt.% with increasing milling time.

  11. Non-polar organic compounds in marine aerosols over the northern South China Sea: Influence of continental outflow.

    PubMed

    Zhao, Yan; Zhang, Yingyi; Fu, Pingqing; Ho, Steven Sai Hang; Ho, Kin Fai; Liu, Fobang; Zou, Shichun; Wang, Shan; Lai, Senchao

    2016-06-01

    Filter samples of total suspended particle (TSP) collected during a cruise campaign over the northern South China Sea (SCS) from September to October 2013 were analyzed for non-polar organic compounds (NPOCs) as well as organic carbon (OC), elemental carbon (EC) and water-soluble ions. A total of 115 NPOCs species in groups of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), iso-/antiso-alkanes, hopanes, steranes, methylalkanes, branched alkanes, cycloalkanes, alkenes and phthalates were detected. The characteristics of NPOCs in marine TSP samples were investigated to understand the sources from the Asian continent and other regions. The concentrations of total NPOCs ranged from 19.8 to 288.2 ng/m(3) with an average of 87.9 ng/m(3), which accounted for 0.8-1.7% (average 1.0%) of organic matter (OM). n-Alkanes was the predominant group, accounting for 43.1-79.5%, followed by PAHs (5.5-44.4%) and hopanes (1.6-11.4%). We found that primary combustion (biomass burning/fossil fuel combustion) was the dominant source for the majority of NPOCs (89.1%). Biomass burning in southern/southeastern China via long-range transport was proposed to be a major contributor of NPOCs in marine aerosols over the northern SCS, suggested by the significant correlations between nss-K(+) and NPOCs groups as well as the analysis of air mass back-trajectory and fire spots. For the samples with strong continental influence, the strong enhancement in concentrations of n-alkanes, PAHs, hopanes and steranes were attributed to fossil fuel (coal/petroleum) combustion. In addition, terrestrial plants waxes were another contributor to NPOCs. PMID:27023121

  12. Source parameter inversion of compound earthquakes on GPU/CPU hybrid platform

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Ni, S.; Chen, W.

    2012-12-01

    Source parameter of earthquakes is essential problem in seismology. Accurate and timely determination of the earthquake parameters (such as moment, depth, strike, dip and rake of fault planes) is significant for both the rupture dynamics and ground motion prediction or simulation. And the rupture process study, especially for the moderate and large earthquakes, is essential as the more detailed kinematic study has became the routine work of seismologists. However, among these events, some events behave very specially and intrigue seismologists. These earthquakes usually consist of two similar size sub-events which occurred with very little time interval, such as mb4.5 Dec.9, 2003 in Virginia. The studying of these special events including the source parameter determination of each sub-events will be helpful to the understanding of earthquake dynamics. However, seismic signals of two distinctive sources are mixed up bringing in the difficulty of inversion. As to common events, the method(Cut and Paste) has been proven effective for resolving source parameters, which jointly use body wave and surface wave with independent time shift and weights. CAP could resolve fault orientation and focal depth using a grid search algorithm. Based on this method, we developed an algorithm(MUL_CAP) to simultaneously acquire parameters of two distinctive events. However, the simultaneous inversion of both sub-events make the computation very time consuming, so we develop a hybrid GPU and CPU version of CAP(HYBRID_CAP) to improve the computation efficiency. Thanks to advantages on multiple dimension storage and processing in GPU, we obtain excellent performance of the revised code on GPU-CPU combined architecture and the speedup factors can be as high as 40x-90x compared to classical cap on traditional CPU architecture.As the benchmark, we take the synthetics as observation and inverse the source parameters of two given sub-events and the inversion results are very consistent with the

  13. Inorganic-organic hybrid compounds: Synthesis and characterization of three new metal phosphonates with similar characteristic structural features

    SciTech Connect

    Bauer, Sebastian; Stock, Norbert . E-mail: stock@ac.uni-kiel.de

    2006-01-15

    The phosphonocarboxylic acid H(HO{sub 3}PCH{sub 2}){sub 2}NH-CH{sub 2}C{sub 6}H{sub 4}-COOH (H{sub 5} L ) was synthesized and characterized by NMR- and IR-spectroscopy, thermogravimetric (TG) analysis and single-crystal X-ray diffraction. Reactions of H{sub 5} L with samarium(III) chloride and calcium(II) chloride resulted in three new compounds, Sm[(O{sub 3}PCH{sub 2}){sub 2}NH-CH{sub 2}C{sub 6}H{sub 4}-COOH].H{sub 2}O (1), Ca[H(O{sub 3}PCH{sub 2}){sub 2}NH-CH{sub 2}C{sub 6}H{sub 4}-COOH].H{sub 2}O (2), and Ca[(HO{sub 3}PCH{sub 2}){sub 2}NH-CH{sub 2}C{sub 6}H{sub 4}-COOH]{sub 2}.4H{sub 2}O (3). The single-crystal structure determination of the title compounds reveals that in H{sub 5} L as well as in compounds 1, 2, and 3 zwitterions are present. Within the M-O building units of the metal phosphonates we observed a different degree of dimensionality, depending on the oxidation state of the metal ion and the synthesis conditions. In 1, one-dimensional chains of edge-sharing SmO{sub 8} polyhedra are observed while in 2, isolated units of edge-sharing CaO{sub 6} octahedra and in 3 isolated CaO{sub 6} octahedra are observed. However, looking at the organic part, the rigid phenyl carboxylic acid moieties arrange in a 'zipper-like' fashion and hydrogen bonding plays an important role in the stabilization of the crystal structure. The title compounds were further characterized by IR spectroscopy and TG analysis. Additionally, the thermal stability of 1 was investigated by temperature-dependent X-ray diffraction. -- Graphical abstract: Hydrothermal reactions of the phosphonocarboxylic acid H(HO{sub 3}PCH{sub 2}){sub 2}NH-CH{sub 2}C{sub 6}H{sub 4}-COOH with Sm{sup 3+} and Ca{sup 2+} salts has led to three new inorganic-organic hybrid compounds. All crystal structures contain phosphonate zwitterions and have a layer-like arrangement. The rigid organic groups arrange in a 'zipper-like' fashion and hydrogen bonding plays an important role in the stabilization of the crystal

  14. Properties of hybrid CVD/PAN graphite fibers and their bromine intercalation compounds

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Lake, Max L.; Moinuddin, Alia; Marabito, Mark

    1992-01-01

    A hybrid fiber with a PAN core surrounded by a vapor grown carbon fiber (VGCF) sheath was fabricated using a proprietary process. The density, ultimate tensile strength, Young's modulus, and resistivity of pristine and bromine intercalated fibers made by this technique having diameters varying from 5 to 50 microns were compared with the values predicted from the rule of mixtures model. For both the pristine and intercalated fibers, the density, ultimate tensile strength, and Young's modulus of the fibers were lower than predicted, but the resistivity was measured to be consistent with predictions. The lower than theoretical mechanical properties may be evidence of a low density disordered interface between the core and the sheath which would lower the density and degrade the mechanical properties, but would leave the resistivity nearly unaffected. Intercalation had little if any effect on the ultimate tensile strength and Young's modulus, but raised the density by about 11 pct., and lowered the resistivity by an order of magnitude. The diameter dependence of the resistivity showed evidence of a depletion layer of the type found in VGCF.

  15. Assessment of the oxidative and hydrolytic degradation of the lipid fraction of mortadella by means of HPSEC analyses of polar compounds.

    PubMed

    Summo, Carmine; Bilancia, Maria Teresa; Caponio, Francesco

    2008-08-01

    The aim of this work was to use the HPSEC analysis of polar compounds to assess the level of oxidative and hydrolytic degradation of the lipid fraction of mortadella. The results indicated high primary oxidative degradation of the lipid fraction in the samples, with a mean value for oxidized triacylglycerols of 1.77%, and low secondary oxidation, with a mean value for triacylglycerol oligopolymers of 0.16%. In addition, in some cases, significant hydrolytic degradation was found. HPSEC analysis of polar compounds, to evaluate the level of oxidative and hydrolytic degradation of the mortadella lipid fraction, could be used as an alternative to commonly used techniques, some of which are not always reliable. PMID:22063035

  16. High polar organic-inorganic hybrid coating stir bar sorptive extraction combined with high performance liquid chromatography-inductively coupled plasma mass spectrometry for the speciation of seleno-amino acids and seleno-oligopeptides in biological samples.

    PubMed

    Mao, Xiangju; Hu, Bin; He, Man; Chen, Beibei

    2012-09-21

    of PSP-TiO(2) organic-inorganic hybrid SBSE coating was based on the cation exchange interaction, which made it feasible to directly extract high polar seleno-amino acids and seleno-oligopeptides in biological samples without derivatization. This coating could also be suitable for stir bar sorptive extraction of other cationic compounds from the environmental and biological samples. PMID:22885051

  17. Evaluation of an in-injection port thermal desorption-gas chromatography/mass spectrometry method for analysis of non-polar organic compounds in ambient aerosol samples.

    PubMed

    Ho, Steven Sai Hang; Yu, Jian Zhen; Chow, Judith C; Zielinska, Barbara; Watson, John G; Sit, Elber Hoi Leung; Schauer, James J

    2008-07-25

    Thermal desorption coupled with gas chromatography/mass spectrometry (TD-GC/MS) is an alternative to solvent extraction (SE)-based GC/MS (SE-GC/MS) for the analysis of non-polar organic compounds in filter or impactor-collected aerosols. TD-GC/MS has no sample pretreatment and requires a small filter aliquot for detecting individual organic compounds. The performance of an in-injection port TD-GC/MS is evaluated for polycyclic aromatic hydrocarbons (PAHs), n-alkanes, iso-/anteiso-alkanes, hopanes, steranes, branched alkanes, cyclohexanes, alkenes, and phthalates in standards and ambient air samples. Replicate analysis for 132 organic compounds showed relative standard deviations <10%, with the majority <5%. Accuracy for 15 PAHs, determined with NIST standard reference material (SRM) 1649a urban dust, was within +/-5% of the certified values. TD-GC/MS and SE-GC/MS method comparisons for 14 Hong Kong ambient samples agreed within 11% for 106 non-polar compounds. For 19 Tong Liang, China samples, agreement was within 13% for 23 PAHs. PMID:18556009

  18. Crystal structure and chemical bonding of novel Li-containing polar intermetallic compound La{sub 11}Li{sub 12}Ge{sub 16}

    SciTech Connect

    Jung, Yaho; Nam, Gnu; Jeon, Jieun; Kim, Youngjo; You, Tae-Soo

    2012-12-15

    A novel Li-containing polar intermetallic compound La{sub 11}Li{sub 12}Ge{sub 16} has been synthesized using the high-temperature reaction method and characterized by both powder and single-crystal X-ray diffractions. The title compound crystallized in the orthorhombic crystal system (space group Immm, Z=2, Pearson symbol oI78) with fifteen crystallographically unique atomic positions in the asymmetric unit, and the lattice parameters are refined as a=4.5244(4) A, b=6.9932(6) A, and c=53.043(5) A. The complex crystal structure of the title compound can be described as a 2:1 intergrowth of two closely related compounds: La{sub 2}Li{sub 2}Ge{sub 3} (Ce{sub 2}Li{sub 2}Ge{sub 3}-type) and La{sub 3}Li{sub 4}Ge{sub 4} (Zr{sub 3}Cu{sub 4}Si{sub 4}-type) acting like 'building-blocks' along the c-axis. Six La sites are categorized into three distinct types based on the local coordination environment showing the coordination numbers of 12-14. Three unique Li sites are placed in the centers of local tetrahedra formed by four Ge atoms which eventually construct Ge{sub 2} dimers or 1-dimensional cis-/trans-Ge chains. Theoretical investigations using the tight-binding linear muffin-tin orbital (LMTO) method provide rationales for an improved structural stability and for unique local coordination geometries established by anionic elements including [LiGe{sub 4}] tetrahedra, cis-/trans-Ge chain and Ge{sub 2} dimers. - Graphical abstract: Reported is a novel ternary Li-containing polar intermetallic compound La{sub 11}Li{sub 12}Ge{sub 16}. The complex crystal structure can be viewed as a simple combination of two closely related known compounds acting as 'building-blocks', La{sub 2}Li{sub 2}G{sub 3} and La{sub 3}Li{sub 4}Ge{sub 4}, in a 2:1 stoichiometric ratio. Highlights: Black-Right-Pointing-Pointer A novel Li-containing polar intermetallic compound La{sub 11}Li{sub 12}Ge{sub 16} was synthesized. Black-Right-Pointing-Pointer The complex crystal structure was easily explained as

  19. End-Group-Functionalized Poly(α-olefinates) as Non-Polar Building Blocks: Self-Assembly of Sugar-Polyolefin Hybrid Conjugates.

    PubMed

    Thomas, Tessy S; Hwang, Wonseok; Sita, Lawrence R

    2016-04-01

    Living coordinative chain-transfer polymerization of α-olefins, followed by chemical functionalization of a Zn(polymeryl)2 intermediate, provides entry to end-group functionalized poly(α-olefinates) (x-PAOs) that can serve as a new class of non-polar building block with tailorable occupied volumes. Application of these x-PAOs for the synthesis and self-assembly of sugar-polyolefin hybrid conjugates demonstrate the ability to manipulate the morphology of the ultra-thin film nanostructure through variation in occupied volume of the x-PAO domain. PMID:26961338

  20. The Synthesis and Characterization of Aromatic Hybrid Anderson-Evans POMs and their Serum Albumin Interactions: The Shift from Polar to Hydrophobic Interactions.

    PubMed

    Al-Sayed, Emir; Blazevic, Amir; Roller, Alexander; Rompel, Annette

    2015-12-01

    Four aromatic hybrid Anderson polyoxomolybdates with Fe(3+) or Mn(3+) as the central heteroatom have been synthesized by using a pre-functionalization protocol and characterized by using single-crystal X-ray diffraction, FTIR, ESI-MS, (1) H NMR spectroscopy, and elemental analysis. Structural analysis revealed the formation of (TBA)3 [FeMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ]⋅3.5 ACN (TBA-FeMo6 -bzn; TBA=tetrabutylammonium, ACN=acetonitrile, bzn=TRIS-benzoic acid alkanolamide, TRISR=(HOCH2 )3 CR)), (TBA)3 [FeMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ]⋅2.5 ACN (TBA-FeMo6 -cin; cin=TRIS-cinnamic acid alkanolamide), (TBA)3 [MnMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ]⋅3.5 ACN (TBA-MnMo6 -bzn), and (TBA)3 [MnMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ]⋅2.5 ACN (TBA-MnMo6 -cin). To make these four compounds applicable in biological systems, an ion exchange was performed that gave the water-soluble (up to 80 mM) sodium salts Na3 [FeMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ] (Na-FeMo6 -bzn), Na3 [FeMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ] (Na-FeMo6 -cin), Na3 [MnMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ] (Na-MnMo6 -bzn), and Na3 [MnMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ] (Na-MnMo6 -cin). The hydrolytic stability of the sodium salts was examined by applying ESI-MS in the pH range of 4 to 9. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that human and bovine serum albumin (HSA and BSA) remain intact in solutions that contain up to 100 equivalents of the sodium salts over more than 4 d at 20 °C. Tryptophan (Trp) fluorescence quenching was applied to study the interactions between the sodium salts and HSA and BSA at pH 5.5 and 7.4. The quenching constants were extracted by using Stern-Volmer analysis, which suggested the formation of a 1:1 POM-protein complex in all samples. It is suggested that the aromatic hybrid POM approaches subdomain IIA of HSA and exhibits hydrophobic interactions with its hydrophobic tails, whereas the Anderson core is stabilized through electrostatic

  1. The Synthesis and Characterization of Aromatic Hybrid Anderson–Evans POMs and their Serum Albumin Interactions: The Shift from Polar to Hydrophobic Interactions

    PubMed Central

    Al-Sayed, Emir; Blazevic, Amir; Roller, Alexander; Rompel, Annette

    2015-01-01

    Four aromatic hybrid Anderson polyoxomolybdates with Fe3+ or Mn3+ as the central heteroatom have been synthesized by using a pre-functionalization protocol and characterized by using single-crystal X-ray diffraction, FTIR, ESI-MS, 1H NMR spectroscopy, and elemental analysis. Structural analysis revealed the formation of (TBA)3[FeMo6O18{(OCH2)3CNHCOC6H5}2]⋅3.5 ACN (TBA-FeMo6-bzn; TBA=tetrabutylammonium, ACN=acetonitrile, bzn=TRIS-benzoic acid alkanolamide, TRIS–R=(HOCH2)3C–R)), (TBA)3[FeMo6O18{(OCH2)3CNHCOC8H7}2]⋅2.5 ACN (TBA-FeMo6-cin; cin=TRIS-cinnamic acid alkanolamide), (TBA)3[MnMo6O18{(OCH2)3CNHCOC6H5}2]⋅3.5 ACN (TBA-MnMo6-bzn), and (TBA)3[MnMo6O18{(OCH2)3CNHCOC8H7}2]⋅2.5 ACN (TBA-MnMo6-cin). To make these four compounds applicable in biological systems, an ion exchange was performed that gave the water-soluble (up to 80 mm) sodium salts Na3[FeMo6O18{(OCH2)3CNHCOC6H5}2] (Na-FeMo6-bzn), Na3[FeMo6O18{(OCH2)3CNHCOC8H7}2] (Na-FeMo6-cin), Na3[MnMo6O18{(OCH2)3CNHCOC6H5}2] (Na-MnMo6-bzn), and Na3[MnMo6O18{(OCH2)3CNHCOC8H7}2] (Na-MnMo6-cin). The hydrolytic stability of the sodium salts was examined by applying ESI-MS in the pH range of 4 to 9. Sodium dodecylsulfate–polyacrylamide gel electrophoresis (SDS-PAGE) showed that human and bovine serum albumin (HSA and BSA) remain intact in solutions that contain up to 100 equivalents of the sodium salts over more than 4 d at 20 °C. Tryptophan (Trp) fluorescence quenching was applied to study the interactions between the sodium salts and HSA and BSA at pH 5.5 and 7.4. The quenching constants were extracted by using Stern–Volmer analysis, which suggested the formation of a 1:1 POM–protein complex in all samples. It is suggested that the aromatic hybrid POM approaches subdomain IIA of HSA and exhibits hydrophobic interactions with its hydrophobic tails, whereas the Anderson core is stabilized through electrostatic interactions with polar amino acid side chains from, for example

  2. Electrons per atom ratio determination and Hume-Rothery electron concentration rule for P-based polar compounds studied by FLAPW-fourier calculations.

    PubMed

    Mizutani, Uichiro; Sato, Hirokazu; Inukai, Manabu; Nishino, Yoichi; Zijlstra, Eeuwe Sieds

    2015-02-01

    The extent to which reliable electrons per atom ratio, e/a, are determined and the validity of the Hume-Rothery stabilization mechanism are ensured upon increasing ionicity are studied by applying first-principles full potential linearized augmented plane wave (FLAPW)-Fourier band calculations to as many as 59 binary compounds formed by adding elements from periods 2-6 to phosphorus in group 15 of the Periodic Table. Van Arkel-Ketelaar triangle maps were constructed both by using the Allen electronegativity data and by using an energy difference between the center-of-gravity energies of FLAPW-derived s and p partial densities of states (DOSs) for the equiatomic compounds studied. The determination of e/a and the test of the interference condition, both of which play a key role in the Hume-Rothery stabilization mechanism, were reliably made for all intermetallic compounds, as long as the ionicity is less than 50%. In the A-P (A = Li, Na, K, Rb, and Cs) compounds with ionicity exceeding 50%, however, e/a determination becomes unstable, as reflected in its P concentration dependence. New Hume-Rothery electron concentration rules were theoretically found in two families of polar compounds: skutterudite compounds TMP(3), TMAs(3), and TMSb(3) (TM = Co, Ni, Rh, and Ir; cI32) with e/a = 4.34 and TM(3)P (TM = Cr, Mn, Fe, and Ni; tI32) with e/a = 2.20. PMID:25531024

  3. Anti-melanogenic effects of resveratryl triglycolate, a novel hybrid compound derived by esterification of resveratrol with glycolic acid.

    PubMed

    Park, Soojin; Seok, Jin Kyung; Kwak, Jun Yup; Choi, Yun-Hyeok; Hong, Seong Su; Suh, Hwa-Jin; Park, Woncheol; Boo, Yong Chool

    2016-07-01

    Resveratrol is known to inhibit cellular melanin synthesis by multiple mechanisms. Glycolic acid (GA) is used in skin care products for its excellent skin penetration. The purpose of this study was to examine the anti-melanogenic effects of resveratryl triglycolate (RTG), a novel hybrid compound of resveratrol and GA, in comparison with resveratrol, GA, resveratryl triacetate (RTA) and arbutin. Resveratrol, RTG, and RTA inhibited the catalytic activity human tyrosinase (TYR) more potently than arbutin or GA did. Their cytotoxic and anti-melanogenic effects were examined using murine melanoma B16/F10 cells and human epidermal melanocytes (HEMs). The cytotoxicity of RTG was similar to that of resveratrol and RTA. RTG at 3-10 μM decreased melanin levels and cellular TYR activities in α-melanocyte-stimulating hormone-stimulated B16/F10 cells, and L-tyrosine-stimulated HEMs. RTG also suppressed mRNA and protein expression of TYR, tyrosinase-related protein 1, L-3,4-dihydroxyphenylalanine chrome tautomerase, and microphthalmia-associated transcription factor (MITF) in HEMs stimulated with L-tyrosine. This study suggests that, like resveratrol and RTA, RTG can attenuate cellular melanin synthesis effectively through the suppression of MITF-dependent expression of melanogenic enzymes and the inhibition of catalytic activity of TYR enzyme. RTG therefore has potential for use as a cosmeceutical ingredient for skin whitening. PMID:27059716

  4. Ampholine-functionalized hybrid organic-inorganic silica material as sorbent for solid-phase extraction of acidic and basic compounds.

    PubMed

    Wang, Tingting; Chen, Yihui; Ma, Junfeng; Chen, Mingliang; Nie, Chenggang; Hu, Minjie; Li, Ying; Jia, Zhijian; Fang, Jianghua; Gao, Haoqi

    2013-09-20

    A novel sorbent for solid-phase extraction (SPE) was synthesized by chemical immobilization of ampholine on hybrid organic-inorganic silica material. The ampholine-functionalized hybrid organic-inorganic silica sorbent is consisted of aliphatic amine groups, carboxyl groups and long carbon chains, allowing for extraction of both acidic and basic compounds. The retention properties of the developed sorbent were evaluated for 1-hydroxy-2-naphthoic acid (HNA), 1-naphthoic acid (NA), 3-hydroxybenzoic acid (HBA), benzoic acid (BA), sorbic acid (SA), vanillic aldehyde (VA), butyl 4-hydroxybenzoate (BHB), propyl 4-hydroxybenzoate (PHB), ethyl 4-hydroxybenzoate (EHB), and methyl 4-hydroxybenzoate (MHB). The results show that such a sorbent has three types of interaction, i.e., electrostatic interaction, hydrophobic interaction, and hydrogen bonding, exhibiting high extraction efficiency towards the compounds tested. The adsorption capacities of the analytes ranged from 0.61 to 6.54μgmg(-1). The reproducibility of the sorbent preparation was evaluated at three spiking concentration levels, with relative standard deviations (RSDs) of 1.0-10.5%. The recoveries of ten acidic and basic compounds spiked in beverage Coca-Cola(®) sample ranged from 82.5% to 98.2% with RSDs less than 5.8%. Under optimum conditions, the ampholine-functionalized hybrid organic-inorganic silica sorbent rendered higher extraction efficiency for acidic compounds than that of the commercially available ampholine-functionalized silica particles, and was comparable to that of the commercial Oasis WAX and Oasis WCX. PMID:23953713

  5. Trace-level determination of polar flavour compounds in butter by solid-phase extraction and gas chromatography-mass spectrometry.

    PubMed

    Adahchour, M; Vreuls, R J; van der Heijden, A; Brinkman, U A

    1999-06-01

    Volatile compounds are responsible for the aromas of butter. A simple technique for the determination of these components is described which is based on solid-phase extraction (SPE) after melting of the butter and separation of the aqueous phase from the fat. Volatile flavours present in the water fraction are collected by off-line SPE on cartidges packed with a copolymer sorbent. After desorption with 500 microliters of methyl acetate, 1-microliter aliquots are quantified and/or identified by gas chromatography-mass spectrometry. The procedure was tested with respect to recovery, linearity and limit of detection in real-life samples using five polar model analytes. It allows the characterisation of polar flavour compounds in butter prior to and after heat treatment at 170 degrees C. From the five model compounds, vanillin, traces of diacetyl and maltol were found to be present in the butter samples. After heat treatment 500-1000-fold increased concentration of maltol, and substantial amounts of furaneol were detected. PMID:10399332

  6. Chromatographic techniques for the determination of alkyl-phenols, tocopherols and other minor polar compounds in raw and roasted cold pressed cashew nut oils.

    PubMed

    Gómez-Caravaca, Ana María; Verardo, Vito; Caboni, Maria Fiorenza

    2010-11-19

    Anacardium occidentale belongs to the family Anacardiaceae and is principally grown in tropical America (Mexico, Peru, Brazil, etc.) and India. Cashew nuts contain low amounts of hydroxy alkyl phenols that come from an oily liquid present in their shell and that is known as cashew-nut shell liquid. This paper reports the alkyl phenols composition of cold pressed raw and roasted cashew nut oil. First of all, cashew nut shell liquid was used for a basic fractionation of the alkyl phenol classes by preparative TLC and definitively identified by GC-MS and GC-FID. Anacardic acids were the major alkylphenols contained in both oils followed by cardol, cardanol and 2-methylcardol compounds, respectively. Raw and roasted oils did not show different compositions except for cardanols. The oil produced from roasted cashew nut reported a higher concentration of cardanols. Furthermore, tocopherols and other minor polar compounds were determined by HPLC-FLD and HPLC-DAD-MS, respectively. Tocopherol content varied in a range of 171.48-29.56mg/100g from raw to roasted cashew nut oil, being β-tocopherol the one which presented a higher decrease (93.68%). Also minor polar compounds in cashew oil decreased after roasting from 346.52 to 262.83mg/kg. PMID:20961547

  7. Characterization of polar polycyclic aromatic compounds in a heavy-duty diesel exhaust particulate by capillary column gas chromatography and high-resolution mass spectrometry

    SciTech Connect

    Bayona, J.M.; Markides, K.E.; Lee, M.L.

    1988-12-01

    Polar normal-phase HPLC fractions of a heavy-duty diesel exhaust particulate, a National Bureau of Standards (NBS) standard reference material (SRM) 1650, were analyzed by capillary column GC coupled to both low- and high-resolution mass spectrometry (HRMS) using electron impact (EI) and negative ion chemical ionization (NICI). Over 80 polycyclic aromatic compounds (PAC), belonging to many different chemical classes (anhydrides, carboxaldehydes, diazaarenes, cyclic imides, nitrohydroxy-PAC, nitroaza-PAC, nitrodiaza-PAC, nitrolactones, and quinones) were tentatively identified. Ten of them were positively identified by comparison of retention times with authentic standards. Among them, phenazine and phthalic anhydride were positively identified for the first time in diesel exhaust particulates. In addition, cyclic imides and their alkylated derivatives were tentatively identified for the first time. Other novel polar chemical classes of PAC were evidenced by MICI MS using a direct-insertion probe.

  8. Synthesis, crystal structure and luminescence properties of one inorganic-organic hybrid compound [FTMA] 2[Co(NCS) 4] (FTMA = ferrocenylmethyltrimethylammonium cation)

    NASA Astrophysics Data System (ADS)

    Bai, Yan; Zhang, Guo-Qiang; Dang, Dong-Bin; Ma, Peng-Tao; Niu, Jing-Yang

    2011-08-01

    A new inorganic-organic hybrid compound [FTMA] 2[Co(NCS) 4] (FTMA = ferrocenylmethyltrimethylammonium cation) has been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Co(II) atom has a distorted tetrahedral environment with four N atoms of four NCS - anions. In the solid state there are C-H⋯π interactions between adjacent ferrocenyl cations, which generate one-dimensional (1-D) supramolecular chain, and C-H⋯S hydrogen bonds between [FTMA] + cations and cobalt thiocyanate anions. The title compound shows strong purple fluorescence emission in the solid state at room temperature.

  9. Synthesis, crystal structure and luminescence properties of one inorganic-organic hybrid compound [FTMA]2[Co(NCS)4] (FTMA = ferrocenylmethyltrimethylammonium cation).

    PubMed

    Bai, Yan; Zhang, Guo-Qiang; Dang, Dong-Bin; Ma, Peng-Tao; Niu, Jing-Yang

    2011-08-01

    A new inorganic-organic hybrid compound [FTMA](2)[Co(NCS)(4)] (FTMA = ferrocenylmethyltrimethylammonium cation) has been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Co(II) atom has a distorted tetrahedral environment with four N atoms of four NCS(-) anions. In the solid state there are C-H⋯π interactions between adjacent ferrocenyl cations, which generate one-dimensional (1-D) supramolecular chain, and C-H⋯S hydrogen bonds between [FTMA](+) cations and cobalt thiocyanate anions. The title compound shows strong purple fluorescence emission in the solid state at room temperature. PMID:21530374

  10. Evaluation of polycaprolactone as a new sorbent coating for determination of polar organic compounds in water samples using membrane-SPME.

    PubMed

    Marcinkowski, Łukasz; Kloskowski, Adam; Spietelun, Agata; Namieśnik, Jacek

    2015-02-01

    Commercially available solid-phase microextraction fibers used for isolation of polar analytes are based on the adsorption phenomenon. In consequence, typical limitations bonded with analytes displacement and matrix effects are very frequent. In the present study, alternative solution is described. Polycaprolactone (PCL) was used for the first time as sorbent to isolate polar organic compounds from water samples using the membrane-solid-phase microextraction (M-SPME) technique. In this technique, due to protective role of the mechanically and thermally stable polydimethylsiloxane (PDMS) membrane, internal polar coating might be melted during extraction and desorption of analytes. In consequence sorbents with low melting points like a PCL might be utilized. Based on chromatographic retention data, triazines were selected as a model compounds for evaluation of the sorptive properties of the polycaprolactone. Applying the screening plan and central composite design, statistically significant parameters influencing extraction efficiency were determined and optimized. The analysis of variance confirmed the significant influence of temperature, salt content, and pH of samples on the extraction efficiency. Besides the new PCL/PDMS fiber, a commercial fiber coated with divinylbenzene/polydimethylsiloxane (DVB/PDMS) was used for comparative studies. The results obtained showed that PCL is an interesting sorbent which can be successfully applied for isolation of polar organics from aqueous matrices at a broad range of analytes concentration. The determined detection limits of procedure based on the novel fiber enable its application at the concentration levels of triazines recommended by the US EPA standards. The practical applicability of the developed fiber has been confirmed by the results based on the analysis of real samples. PMID:25416232

  11. Mechanisms of G1 cell cycle arrest and apoptosis in myeloma cells induced by hybrid-compound histone deacetylase inhibitor

    SciTech Connect

    Fujii, Seiko; Okinaga, Toshinori; Ariyoshi, Wataru; Takahashi, Osamu; Iwanaga, Kenjiro; Nishino, Norikazu; Tominaga, Kazuhiro; Nishihara, Tatsuji

    2013-05-10

    Highlights: •Novel histone deacetylase inhibitor Ky-2, remarkably inhibits myeloma cell growth. •Ky-2 demonstrates no cytotoxicity against normal lymphocytic cells. •Ky-2 induces cell cycle arrest through the cell cycle-associated proteins. •Ky-2 induces Bcl-2-inhibitable apoptosis through a caspase-dependent cascade. -- Abstract: Objectives: Histone deacetylase (HDAC) inhibitors are new therapeutic agents, used to treat various types of malignant cancers. In the present study, we investigated the effects of Ky-2, a hybrid-compound HDAC inhibitor, on the growth of mouse myeloma cells. Materials and methods: Myeloma cells, HS-72, P3U1, and mouse normal cells were used in this study. Effect of HDAC inhibitors on cell viability was determined by WST-assay and trypan blue assay. Cell cycle was analyzed using flow cytometer. The expression of cell cycle regulatory and the apoptosis associated proteins were examined by Western blot analysis. Hoechst’s staining was used to detect apoptotic cells. Results: Our findings showed that Ky-2 decreased the levels of HDACs, while it enhanced acetylation of histone H3. Myeloma cell proliferation was inhibited by Ky-2 treatment. Interestingly, Ky-2 had no cytotoxic effects on mouse normal cells. Ky-2 treatment induced G1-phase cell cycle arrest and accumulation of a sub-G1 phase population, while Western blotting analysis revealed that expressions of the cell cycle-associated proteins were up-regulated. Also, Ky-2 enhanced the cleavage of caspase-9 and -3 in myeloma cells, followed by DNA fragmentation. In addition, Ky-2 was not found to induce apoptosis in bcl-2 overexpressing myeloma cells. Conclusion: These findings suggest that Ky-2 induces apoptosis via a caspase-dependent cascade and Bcl-2-inhibitable mechanism in myeloma cells.

  12. Preparation of polypyrrole composite solid-phase microextraction fiber coatings by sol-gel technique for the trace analysis of polar biological volatile organic compounds.

    PubMed

    Zhang, Zhuomin; Zhu, Li; Ma, Yunjian; Huang, Yichun; Li, Gongke

    2013-02-21

    Two novel polypyrrole (PPy) composite solid-phase microextraction (SPME) fiber coatings involving polypyrrole β-naphthalenesulfonic acid (PPy/β-NSA) and polypyrrole graphene (PPy/GR) composite SPME fiber coatings were prepared by a simple sol-gel technique for selectively sampling relatively polar biological volatile organic compounds (VOCs). Crucial preparation conditions of the PPy composite SPME fiber coatings were optimized and are discussed in detail. Physical tests suggested that the PPy composite SPME fiber coatings possessed a porous surface morphology, stable chemical and thermal properties. Due to the inducing polar functional groups in the PPy molecule, the PPy composite SPME fiber coatings achieved a higher extraction capacity and special selectivity for the polar biological VOCs with conjugate structures, compared with commercial SPME fiber coatings. Enrichment factors of most of the VOCs by the PPy/β-NSA and PPy/GR SPME fibers were much higher than those achieved by common commercially available SPME fiber coatings. Finally, the PPy/β-NSA and PPy/GR SPME fiber coatings were applied for the trace analysis of typical polar VOCs from ant and coriander samples coupled with gas chromatography/mass spectrometry (GC/MS) detection, respectively. It was satisfactory that the average contents of 4-heptanone, 4-heptanol, 4-nonanone and methyl 5-methylsalicylate from ant samples were actually found to be 28.0, 58.7, 3.0 and 0.6 μg g(-1), and the average contents of nonane, decanal, undecanal and dodecanal from coriander samples were actually found to be 0.79, 0.13, 0.06 and 0.21 μg g(-1). The results suggested that PPy composite SPME coatings will be a potentially excellent sampling technique for the trace analysis of polar biological VOCs. PMID:23282483

  13. SAMPLE EXTRACTION AND GC-MS ANALYSIS FOR POLAR VOLATILE ORGANIC COMPOUNDS (PVOCS) IN LIQUID BIOLOGICAL MEDIA

    EPA Science Inventory

    Current approaches for assessing the cumulative exposures and effects from broad classes of environmental stressors incorporate the measurement of specific groups of endogenous compounds in human biological fluids. Recent focus has been on interpreting patterns of differentially...

  14. Controllable Assembly of Vanadium-Containing Polyoxoniobate-Based Three-Dimensional Organic-Inorganic Hybrid Compounds and Their Photocatalytic Properties.

    PubMed

    Hu, Jufang; Wang, Yin; Zhang, Xinning; Chi, Yingnan; Yang, Song; Li, Jikun; Hu, Changwen

    2016-08-01

    The controllable synthesis of two vanadium-containing polyoxoniobate-based three-dimensional organic-inorganic hybrid compounds, [Co(pn)2]4[HPNb10V(IV)2O40(V(IV)O)4]·17H2O (1) and [Co(pn)2]5[PNb12O40(V(IV)O)6](OH)7·15H2O (2), where pn = 1,2-diaminopropane, is realized by changing the hydrothermal temperature or adding N-(aminoethyl)piperazine as an additive. Both compounds 1 and 2 are structurally characterized by single-crystal/powder X-ray diffraction and IR and X-ray photoelectron spectroscopy. Compound 1 features a new divanadium-substituted Keggin polyoxoniobate capped by four vanadyl groups, and the polyanion in 2 exhibits the highest coordination number (10-connected) in polyoxoniobate chemistry. Moreover, the photocatalytic activities of 1 and 2 for hydrogen evolution are preliminarily assessed. PMID:27442602

  15. Evaluation of the use of performance reference compounds in an oasis-HLB adsorbent based passive sampler for improving water concentration estimates of polar herbicides in freshwater

    USGS Publications Warehouse

    Mazzella, N.; Lissalde, S.; Moreira, S.; Delmas, F.; Mazellier, P.; Huckins, J.N.

    2010-01-01

    Passive samplers such as the Polar Organic Chemical Integrative Sampler (POCIS) are useful tools for monitoring trace levels of polar organic chemicals in aquatic environments. The use of performance reference compounds (PRC) spiked into the POCIS adsorbent for in situ calibration may improve the semiquantitative nature of water concentration estimates based on this type of sampler. In this work, deuterium labeled atrazine-desisopropyl (DIA-d5) was chosen as PRC because of its relatively high fugacity from Oasis HLB (the POCIS adsorbent used) and our earlier evidence of its isotropic exchange. In situ calibration of POCIS spiked with DIA-d5was performed, and the resulting time-weighted average concentration estimates were compared with similar values from an automatic sampler equipped with Oasis HLB cartridges. Before PRC correction, water concentration estimates based on POCIS data sampling ratesfrom a laboratory calibration exposure were systematically lower than the reference concentrations obtained with the automatic sampler. Use of the DIA-d5 PRC data to correct POCIS sampling rates narrowed differences between corresponding values derived from the two methods. Application of PRCs for in situ calibration seems promising for improving POCIS-derived concentration estimates of polar pesticides. However, careful attention must be paid to the minimization of matrix effects when the quantification is performed by HPLC-ESI-MS/MS. ?? 2010 American Chemical Society.

  16. A novel hybrid aspirin-NO-releasing compound inhibits TNFalpha release from LPS-activated human monocytes and macrophages

    PubMed Central

    Turnbull, Catriona M; Marcarino, Paolo; Sheldrake, Tara A; Lazzarato, Loretta; Cena, Clara; Fruttero, Roberta; Gasco, Alberto; Fox, Sarah; Megson, Ian L; Rossi, Adriano G

    2008-01-01

    Background The cytoprotective nature of nitric oxide (NO) led to development of NO-aspirins in the hope of overcoming the gastric side-effects of aspirin. However, the NO moiety gives these hybrids potential for actions further to their aspirin-mediated anti-platelet and anti-inflammatory effects. Having previously shown that novel NO-aspirin hybrids containing a furoxan NO-releasing group have potent anti-platelet effects, here we investigate their anti-inflammatory properties. Here we examine their effects upon TNFα release from lipopolysaccharide (LPS)-stimulated human monocytes and monocyte-derived macrophages and investigate a potential mechanism of action through effects on LPS-stimulated nuclear factor-kappa B (NF-κB) activation. Methods Peripheral venous blood was drawn from the antecubital fossa of human volunteers. Mononuclear cells were isolated and cultured. The resultant differentiated macrophages were treated with pharmacologically relevant concentrations of either a furoxan-aspirin (B8, B7; 10 μM), their respective furazan NO-free counterparts (B16, B15; 10 μM), aspirin (10 μM), existing nitroaspirin (NCX4016; 10 μM), an NO donor (DEA/NO; 10 μM) or dexamethasone (1 μM), in the presence and absence of LPS (10 ng/ml; 4 h). Parallel experiments were conducted on undifferentiated fresh monocytes. Supernatants were assessed by specific ELISA for TNFα release and by lactate dehydrogenase (LDH) assay for cell necrosis. To assess NF-κB activation, the effects of the compounds on the loss of cytoplasmic inhibitor of NF-κB, IκBα (assessed by western blotting) and nuclear localisation (assessed by immunofluorescence) of the p65 subunit of NF-κB were determined. Results B8 significantly reduced TNFα release from LPS-treated macrophages to 36 ± 10% of the LPS control. B8 and B16 significantly inhibited monocyte TNFα release to 28 ± 5, and 49 ± 9% of control, respectively. The B8 effect was equivalent in magnitude to that of dexamethasone, but

  17. High extraction efficiency fiber coated with calix[4] open-chain crown ether for solid-phase microextraction of polar aromatic and aliphatic compounds.

    PubMed

    Liu, Mingming; Zeng, Zhaorui; Lei, Yun; Li, Haibing

    2005-11-01

    The calix[4] open-chain crown ether, 5,11,17,23-tetra-tert-butyl-25,27-di(2-allyloxyethoxyl)-26,28-dihydroxycalix[4]arene was synthesized and used for preparation of solid-phase microextraction (SPME) fibers of enhanced extraction efficiency. The new SPME coating made from calix[4] open-chain crown ether and hydroxyl-terminated silicone oil was developed with the aid of vinyltriethoxylsilane as bridge using sol-gel method and cross-linking technology. The efficiency of the novel fiber in the extraction of polar aromatic and aliphatic compounds, such as phenols, alcohols, and volatile fatty acids, was also investigated. Due to the introduction of the polar open-chain crown ether in calix[4]arene molecules, the calix[4] open-chain crown ether fiber showed much better selectivity and sensitivity to these polar compounds in comparison with calix[4]arene fiber. It also had superior extraction efficiency when compared to commercial poly(dimethylsiloxane)-divinylbenzene and polyacrylate fibers. Parts per billion to parts per trillion level detection limits were achieved for most of the analytes through SPME in conjunction with GC and flame ionization detector. The linear ranges were two to four orders of magnitude, and the RSD values were below 7% for all analytes. The novel fiber was applied to determine volatile alcohols and fatty acids in wine samples. The volatile-free wine prepared in this work was used to assure similar chemical environment for analytes in both calibration solutions and in real wine samples, thus compensating for possible matrix interferences. The established internal standard method using 4-methyl-2-pentanol as internal standard showed satisfactory accuracy and precision. PMID:16342796

  18. HPLC-DAD-q-TOF-MS as a powerful platform for the determination of phenolic and other polar compounds in the edible part of mango and its by-products (peel, seed, and seed husk).

    PubMed

    Gómez-Caravaca, Ana María; López-Cobo, Ana; Verardo, Vito; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

    2016-04-01

    Free and bound phenolic and other polar compounds in mango edible fraction and its by-products (peel, seed, and seed husk) have been determined by HPLC-DAD-ESI-qTOF-MS. This analytical technique has demonstrated to be a valuable platform for the identification and quantification of these compounds in mango. In fact, UV-Vis and mass spectra data allowed the determination of 91 free compounds and 13 bound (cell wall linked) compounds taking into account the four fractions of mango. To our knowledge, this is the first time that mango seed husk has been studied regarding its phenolic compounds. The method proposed showed LODs between 0.006 and 0.85 μg/mL and accuracy ranged from 94.8 and 100.7%. Mango peel presented the highest concentration of free polar compounds followed by seed, pulp, and seed husk. It is also important to highlight that bound phenolic compounds had never been determined in mango pulp, seed, and seed husk before. Furthermore, ellagic acid was the most abundant bound compound in the four mango fractions analyzed. These results show that mango pulp and its by-products are a good source of phenolic and other polar compounds. In particular, mango seed contains a high total concentration of ellagic acid (650 mg/100 g dry weight). PMID:26703086

  19. IDENTIFICATION AND QUANTIFICATION OF AEROSOL POLAR OXYGENATED COMPOUNDS BEARING CARBOXYLIC AND/OR HYDROXYL GROUPS. 1. METHOD DEVELOPMENT

    EPA Science Inventory

    In this study, a new analytical technique was developed for the identification and quantification of multi-functional compounds containing simultaneously at least one hydroxyl or one carboxylic group, or both. This technique is based on derivatizing first the carboxylic group(s) ...

  20. A polarization-independent terahertz plasmon-induced transparency metamaterial based on hybrid graphene-gold structure for bio-sensing

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaolei; Yuan, Cai; Lv, Wenhua; Xu, Shilin; Yao, Jianquan

    2016-02-01

    A polarization-independent terahertz metamaterial based on hybrid graphene-gold structure with excellent refractive index sensing characteristics is proposed. The proposed structure exhibits a sharply narrow plasmon-induced transparency peak in the transmission spectrum at the terahertz regime. Obvious frequency shift in the transparency peak can be observed by varying the surrounding medium's refractive index or the Fermi level in graphene, which can be well applied in bio-sensing technology. Moreover, an electrical RLC circuit model is used to provide a reasonable explanation for the optical response process in the proposed structure. Our work can offer reference value for the application of graphene technology as well as new idea for designing novel biosensors.

  1. Eugenia calycina Cambess extracts and their fractions: Their antimicrobial activity and the identification of major polar compounds using electrospray ionization FT-ICR mass spectrometry.

    PubMed

    Ferreira, Fernanda P S; Morais, Sandra R; Bara, Maria T F; Conceição, Edemilson C; Paula, José R; Carvalho, Thays C; Vaz, Boniek G; Costa, Helber B; Romão, Wanderson; Rezende, Maria H

    2014-10-01

    Eugenia calycina, which is described as "red pitanga or pitanga cherry of cerrado," is widely distributed in the Cerrado area of Brazil. Its leaf and bark extracts are used in folk medicine for many applications. In this study, the compositions of the major polar compounds of the bark and leaf extracts and their fractions were obtained from a liquid-liquid extraction using hexane, dichloromethane, ethyl acetate, and water. They were then evaluated using electrospray ionization negative FT-ICR mass spectrometry (ESI(-) FT-ICR MS), which revealed a large number of oxygen-containing compounds, such as flavonoids, terpenes, tanins, steroids, and fat acids. The biological activity of these extracts towards several bacterial and fungal strains was then evaluated. The highest activity was found using aqueous fractions, in which the ESI(-) FT-ICR MS analysis revealed compounds with a high content of oxygen (e.g., glycosed flavonoids, tannins, and polyphenolic compounds) against Cryptococcus sp. D (minimum inhibitory concentration [MIC]=15.62μg/mL). Strong activity was also found using the hexanic fractions-in which the ESI(-) FT-ICR MS analysis revealed that the compounds contained a decreased amount of oxygen (e.g., fat acids and steroids)-towards Cryptococcus gatti L48, Cryptococcus neoformans L3 (MIC=31.2μg/mL), and Cryptococcus sp. D (MIC=62.5μg/mL). Therefore, antimicrobial assays using the bark/leaf extracts of E. calycina present prospects for the research of active substances that may be used for the treatment of cryptococcosis, a disease that is common in immunosuppressed patients. PMID:25108373

  2. Coupling physical chemical techniques with hydrotalcite-like compounds to exploit their structural features and new multifunctional hybrids with luminescent properties.

    PubMed

    Costantino, Umberto; Costantino, Ferdinando; Elisei, Fausto; Latterini, Loredana; Nocchetti, Morena

    2013-08-28

    Hydrotalcite-like compounds (HTlc), belonging to the large class of Layered Double Hydroxides (LDH), have excited wide interest owing to the incredible number of their potential and achieved applications in physical, chemical and bio-chemical fields. This perspective review deals with recent advances in the application of physical-chemical techniques for the study of HTlc structure and for the design and synthesis, using intercalation chemistry routes, of new hybrid materials. Firstly, a rapid survey on the most common synthetic strategies for the attainment of HTlc with different crystallinity degree and crystal size and for their modification to obtain hybrids has been made, and the use of coupled techniques (XRPD, luminescence, Solid State MAS NMR and Molecular Dynamics) to gain structural information is reported. Then, the design, synthesis and photophysical characterization of azoic dyes-intercalated and co-intercalated HTlc hybrid materials are described. Hybrids constituted of ZnAl-HTlc, co-intercalated with stearate anions and methyl orange or methyl yellow dyes, have been used as nanofillers of hydrophobic polymers. The polymeric nano-composites obtained have been characterized by means of XRPD patterns, Thermo-Gravimetric Analysis and Confocal Fluorescence Microscopy. This latter technique has been found to be an excellent, complementary and non-invasive tool to probe the dispersion degree of the fluorescent fillers into the polymeric matrices and their stability in the compounding process. Finally, the synthesis and spectroscopic characterization of nanoparticle (NP) decorated HTlc for advanced antimicrobial and photo-catalytic applications are also reported. The review terminates with a concluding short note and future trends. PMID:23812233

  3. Comparison of major taste compounds and antioxidative properties of fruits and flowers of different Sambucus species and interspecific hybrids.

    PubMed

    Mikulic-Petkovsek, Maja; Ivancic, Anton; Schmitzer, Valentina; Veberic, Robert; Stampar, Franci

    2016-06-01

    Differences in the content of sugars, organic acids, total phenolics and antioxidative activity have been evaluated among three different elderberry species (Sambucus nigra, Sambucus cerulea, Sambucus javanica) and seven interspecific hybrids. The highest content of sugars has been determined in the fruits of JA×CER hybrid and the lowest in fruits of (JA×NI)×cv. Black Beauty hybrid. S. nigra berries contained highest levels of total organic acids. S. nigra and (JA×NI)×CER flower extracts were characterized by 1.3- to 2.8-fold higher content of total sugars compared to other species/hybrids analyzed. Total phenolic content (TPC) in berries ranged from 3687 to 6831 mg GAE per kg FW. The highest TPC has been determined in S. nigra fruits and flowers. The ABTS scavenging activity differed significantly among species and hybrids and ranged from 3.2 to 39.59 mM trolox/kgF W in fruits and 44.87-118.26 mM trolox/kg DW in flowers. PMID:26830570

  4. A 640×512-20μm dual-polarity ROIC for MWIR and LWIR hybrid FPAs

    NASA Astrophysics Data System (ADS)

    Eminoglu, Selim; Incedere, O. Samet; Bayhan, Nusret; Isikhan, Murat; Soyer, S. T.; Ustundag, C. M. B.; Kocak, Serhat; Turan, Ozge; Eksi, Umut; Akin, Tayfun

    2016-05-01

    This paper reports the development of a new dual-polarity Direct-Injection (DI) Readout Integrated Circuit (ROIC), called MT6420DDA, designed to support back-to-back connected photodiodes with a single contact per pixel using dual pixel input circuitries suitable for both p-on-n and n-on-p type detectors. The ROIC has a format of 640 × 512 (VGA) and a pixel pitch of 20μm, and can be used to build dual-color or dual-band FPAs working in the MWIR and/or LWIR bands. The ROIC supports snapshot operation with Integrate-then-Read (ITR) and Integrate-while-Read modes (IWR). MT6420DDA has a system-on-chip architecture, with programmable biasing, timing, and configuration. The ROIC supports 2, 4, and 8-output modes at pixel output rates up to 12.5 MHz per output. It runs on 3.3 V analog and 1.8 V digital supplies, and dissipates less than 135 mW in the 4-output mode at 10 MHz. The ROIC has separate programmable full well capacitance values of 1.5 Me-, 3.0 Me-, and 6.0 Me- for both polarities in the high-gain (HG), mid-gain (MG), and low-gain (LG) modes. The ROIC supports two type of polarity switching modes as PSBF (Polarity Switching between Frames) and PSWF (Polarity Switching within Frames). In the PSBF modes, an alternating input polarity is used for each detector type for each frame during each integration period, possibly with different full-well and integration time settings. In the PSWF mode, both type of pixels are exposed almost simultaneously, where detector current is integrated in a time multiplexed manner using the two separate integration capacitors of the pixel input circuitry. The PSBF mode is simple, but the time stamp for each image frame is different. The PSWF mode is complex, but results in a pseudo simultaneous registration of images for each color or spectral band. The ROIC has been developed for cryogenic operation down to 65K with an input referred noise level of less than 470 e- rms in the low-gain (LG) mode at 77K. The MT6420DDA ROIC has been

  5. Preconcentration of polar phenolic compounds from water samples and soil extract by liquid-phase microextraction and determination via liquid chromatography with ultraviolet detection.

    PubMed

    Dolatto, Rafael Garrett; Messerschmidt, Iara; Pereira, Betânia Fraga; Martinazzo, Rosane; Abate, Gilberto

    2016-02-01

    This work proposes a liquid-phase microextraction (LPME) method to extract the highly polar compounds phenol (Ph), o-cresol (o-Cr), m-cresol (m-Cr), p-cresol (p-Cr), and 2,4-dimethylphenol (2,4-DMP) from aqueous matrices. The first extraction step of the LPME method employed a common volumetric flask and n-octanol, and the second extraction step used NaOH as the acceptor phase. The optimized extraction conditions were 900 μL of n-octanol as the extraction solvent, NaOH at 0.60 mol L(-1) as the acceptor phase, an extraction time of 5.0 min, HCl at 0.01 mol L(-1) and NaCl at 20.0% as the donor phase, and an extraction temperature of 20.0°C. The analysis of 50.0 mL of aqueous sample, pretreated under the optimized LPME conditions, afforded a limit of detection (LOD) between 0.3 and 3.5 μg L(-1), a limit of quantification (LOQ) between 1.2 and 11.6 μg L(-1), and a linear range from 2.50 to 50.0 μg L(-1) for Ph, o-Cr, m-Cr and p-Cr and from 12.5 to 250 μg L(-1) for 2,4-DMP. The proposed LPME method was a successful sample preparation strategy, and allowed for precise and accurate quantification of polar phenolic compounds in aqueous matrices such as tap water, river water, groundwater, and seawater, and also in a soil extract. The recovery values ranged from 72.5% to 126.0%, and the relative standard deviation was between 0.3 and 11.5%. PMID:26653452

  6. Quantitative structure-property relationship analysis for the retention index of fragrance-like compounds on a polar stationary phase.

    PubMed

    Rojas, Cristian; Duchowicz, Pablo R; Tripaldi, Piercosimo; Pis Diez, Reinaldo

    2015-11-27

    A quantitative structure-property relationship (QSPR) was developed for modeling the retention index of 1184 flavor and fragrance compounds measured using a Carbowax 20M glass capillary gas chromatography column. The 4885 molecular descriptors were calculated using Dragon software, and then were simultaneously analyzed through multivariable linear regression analysis using the replacement method (RM) variable subset selection technique. We proceeded in three steps, the first one by considering all descriptor blocks, the second one by excluding conformational descriptor blocks, and the last one by analyzing only 3D-descriptor families. The models were validated through an external test set of compounds. Cross-validation methods such as leave-one-out and leave-many-out were applied, together with Y-randomization and applicability domain analysis. The developed model was used to estimate the I of a set of 22 molecules. The results clearly suggest that 3D-descriptors do not offer relevant information for modeling the retention index, while a topological index such as the Randić-like index from reciprocal squared distance matrix has a high relevance for this purpose. PMID:26521096

  7. An exploratory investigation of polar organic compounds in waters from a lead–zinc mine and mill complex

    USGS Publications Warehouse

    Rostad, Colleen E.; Schmitt, Christopher J.; Schumacher, John G.; Leiker, Thomas J.

    2011-01-01

    Surface water samples were collected in 2006 from a lead mine-mill complex in Missouri to investigate possible organic compounds coming from the milling process. Water samples contained relatively high concentrations of dissolved organic carbon (DOC; greater than 20 mg/l) for surface waters but were colorless, implying a lack of naturally occurring aquatic humic or fulvic acids. Samples were extracted by three different types of solid-phase extraction and analyzed by electrospray ionization/mass spectrometry. Because large amounts of xanthate complexation reagents are used in the milling process, techniques were developed to extract and analyze for sodium isopropyl xanthate and sodium ethyl xanthate. Although these xanthate reagents were not found, trace amounts of the degradates, isopropyl xanthyl thiosulfonate and isopropyl xanthyl sulfonate, were found in most locations sampled, including the tailings pond downstream. Dioctyl sulfosuccinate, a surfactant and process filtering aid, was found at concentrations estimated at 350 μg/l at one mill outlet, but not downstream. Release of these organic compounds downstream from lead-zinc mine and milling areas has not previously been reported. A majority of the DOC remains unidentified.

  8. Spin Polarization Inversion at Benzene-Absorbed Fe4N Surface

    PubMed Central

    Zhang, Qian; Mi, Wenbo; Wang, Xiaocha; Wang, Xuhui

    2015-01-01

    We report a first-principle study on electronic structure and simulation of the spin-polarized scanning tunneling microscopy graphic of a benzene/Fe4N interface. Fe4N is a compound ferromagnet suitable for many spintronic applications. We found that, depending on the particular termination schemes and interface configurations, the spin polarization on the benzene surface shows a rich variety of properties ranging from cosine-type oscillation to polarization inversion. Spin-polarization inversion above benzene is resulting from the hybridizations between C pz and the out-of-plane d orbitals of Fe atom. PMID:26012892

  9. Extracted Venom and Cuticular Compounds of Imported Fire Ants, Solenopsis spp., and Chemotaxonomic Applications Across a Persistent Hybrid Zone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Characterization of cuticular biomolecular assemblages for imported fire ants permit basic distinctions among colonies of S. invicta, S. richteri, and their hybrids; thus, providing opportunities to investigate details of landscape ecology for this species complex as well as to assess levels of inva...

  10. SrZn2Sn2 and Ca2Zn3Sn6 — two new Ae-Zn-Sn polar intermetallic compounds (Ae: alkaline earth metal)

    NASA Astrophysics Data System (ADS)

    Stegmaier, Saskia; Fässler, Thomas F.

    2012-08-01

    SrZn2Sn2 and Ca2Zn3Sn6, two closely related new polar intermetallic compounds, were obtained by high temperature reactions of the elements. Their crystal structures were determined with single crystal XRD methods, and their electronic structures were analyzed by means of DFT calculations. The Zn-Sn structure part of SrZn2Sn2 comprises (anti-)PbO-like {ZnSn4/4} and {SnZn4/4} layers. Ca2Zn3Sn6 shows similar {ZnSn4/4} layers and {Sn4Zn} slabs constructed of a covalently bonded Sn scaffold capped by Zn atoms. For both phases, the two types of layers are alternatingly stacked and interconnected via Zn-Sn bonds. SrZn2Sn2 adopts the SrPd2Bi2 structure type, and Ca2Zn3Sn6 is isotypic to the R2Zn3Ge6 compounds (R=La, Ce, Pr, Nd). Band structure calculations indicate that both SrZn2Sn2 and Ca2Zn3Sn6 are metallic. Analyses of the chemical bonding with the electron localization function (ELF) show lone pair like basins at Sn atoms and Zn-Sn bonding interactions between the layers for both title phases, and covalent Sn-Sn bonding within the {Sn4Zn} layers of Ca2Zn3Sn6.

  11. Comprehensive two dimensional gas chromatography with fast-quadrupole mass spectrometry detector analysis of polar compounds extracted from the bio-oil from the pyrolysis of sawdust.

    PubMed

    Schneider, Jaderson K; da Cunha, Michele E; dos Santos, Anaí L; Maciel, Gabriela P S; Brasil, Márcia C; Pinho, Andrea R; Mendes, Fábio L; Jacques, Rosângela A; Caramão, Elina B

    2014-08-22

    In this paper it is studied the most polar fractions of bio-oil produced by fast pyrolysis of Lignocel BK40-90 (sawdust from forest timber). The biomass was submitted to the pyrolysis in an existing FCC pilot plant that was adapted for this procedure. The equipment consists of a fluidized bed reactor with nitrogen injection. The unit operates with continuous biomass feeding and continuous solids circulation. The produced bio-oil was submitted to an aqueous alkaline extraction, isolating the acidic compounds that were analyzed by one-dimensional gas chromatography and comprehensive two-dimensional gas chromatography with quadrupole mass spectrometry detection (qMS). One hundred and thirty compounds (mainly phenols and ketones) were tentatively identified in the extract, some of them by the use of retention indexes. The main differences between chromatographic techniques were the substantial increasing in the peak capacity of GC×GC and the resolution of some co-elutions that occurred in GC/qMS. It is also possible to conclude that this extract is rich in important raw materials for the chemical industry and can be used for this end. PMID:25022485

  12. Exploring the possibilities of capacitively coupled contactless conductivity detection in combination with liquid chromatography for the analysis of polar compounds using aminoglycosides as test case.

    PubMed

    Jankovics, Péter; Chopra, Shruti; El-Attug, Mohamed N; Cabooter, Deirdre; Wolfs, Kris; Noszál, Béla; Van Schepdael, Ann; Adams, Erwin

    2015-08-10

    The analysis of highly polar (often charged) compounds which lack a strong UV absorbing chromophore is really challenging. Despite the numerous analytical methods published, the demand for a simple, robust and cheap technique for their analysis still persists. Here, reversed phase (RP) liquid chromatography (LC) with capacitively coupled contactless conductivity detection (C(4)D) was explored for the first time as a possible method for separation and detection of various aminoglycoside (AMG) antibiotics which were taken as typical test compounds: tobramycin (TOB), spectinomycin, streptomycin, amikacin, kanamycin A and kanamycin B. C(4)D was performed using a commercially available as well as a laboratory made cell. As ion-pairing reagents (IPR) four perfluorinated carboxylic acids were used: pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid (NFPA) and pentadecafluorooctanoic acid (PDFOA). 0.125 mM NFPA-acetonitrile (ACN) (90:10) or 0.125 mM PDFOA-ACN (70:30) as mobile phases were suitable to detect TOB with reasonable retention times. However, NFPA was preferred for practical reasons. Its applicable concentration range in the mobile phase was strongly restricted by loss of chromatographic performance at lower levels and excessive background conductivity at higher levels. Overall repeatability and robustness of the method were rather poor which was explained by the relatively low IPR levels. Selectivity between the tested AMGs was mainly influenced by the number of protonated amino groups per molecule making it impossible to separate compounds of equal net charges. Problems encountered with gradient elution, hydrophilic interaction liquid chromatography (HILIC) and separation at high pH without IPRs are also discussed. PMID:25549929

  13. QSRR Models for Kováts’ Retention Indices of a Variety of Volatile Organic Compounds on Polar and Apolar GC Stationary Phases Using Molecular Connectivity Indexes

    PubMed Central

    Faham, Shadab

    2010-01-01

    Quantitative structure-retention relationship (QSRR) approaches, based on molecular connectivity indices are useful to predict the gas chromatography of Kováts relative retention indices (GC-RRIs) of 132 volatile organic compounds (VOCs) on different 12 (4 apolar and 8 polar) stationary phases (C67, C103, C78, C∞, POH, TTF, MTF, PCL, PBR, TMO, PSH and PCN) at 130 °C. Full geometry optimization based on Austin model 1 semi-empirical molecular orbital method was carried out. The sets of 30 molecular descriptors were derived directly from the topological structures of the compounds from DRAGON program. By means of the final variable selection method, which is elimination selection stepwise regression algorithms, three optimal descriptors were selected to develop a QSRR model to predict the RRI of organic compounds on each stationary phase with a correlation coefficient between 0.9378 and 0.9673 and a leave-one-out cross-validation correlation coefficient between 0.9325 and 0.9653. The root mean squares errors over different 12 phases were within the range of 0.0333–0.0458. Furthermore, the accuracy of all developed models was confirmed using procedures of Y-randomization, external validation through an odd–even number and division of the entire dataset into training and test sets. A successful interpretation of the complex relationship between GC RRIs of VOCs and the chemical structures was achieved by QSRR. The three connectivity indexes in the models are also rationally interpreted, which indicated that all organic compounds’ RRI was precisely represented by molecular connectivity indexes. Electronic supplementary material The online version of this article (doi:10.1365/s10337-010-1741-4) contains supplementary material, which is available to authorized users. PMID:21088689

  14. Synthesis, structure and in vitro antibacterial activities of new hybrid disinfectants quaternary ammonium compounds: pyridinium and quinolinium stilbene benzenesulfonates.

    PubMed

    Chanawanno, Kullapa; Chantrapromma, Suchada; Anantapong, Theerasak; Kanjana-Opas, Akkharawit; Fun, Hoong-Kun

    2010-09-01

    The series of pyridinium (1-10) and quinolinium (11-20) stilbene benzenesulfonates have been synthesized and their structures were investigated by UV-vis, FT-IR and (1)H NMR spectroscopy. In addition, compound 5 was also determined by single crystal X-ray diffraction technique. The antibacterial activity of the synthesized compounds against both gram-positive and gram-negative bacteria has been determined. The quinolinium derivatives exhibited two very potent characteristic activities, namely, (i) specific activity to Methicillin-Resistant Staphylococcus aureus and (ii) with broad band spectrum activity. Compounds 11, 13 and 14 are the most active showing broad spectrum antibacterial activity against gram-positive (Methicillin-Resistant S. aureus, S. aureus, Bacillus subtilis, Vancomycin-Resistant Enterococcus faecalis and E. faecalis) and gram-negative bacterium (Shigella sonnei). The MICs of these compounds were found to be better than that of Benzalkonium chloride (BZK), the commercially used disinfectant. PMID:20619939

  15. Novel Hybrid Compound of a Plinabulin Prodrug with an IgG Binding Peptide for Generating a Tumor Selective Noncovalent-Type Antibody-Drug Conjugate.

    PubMed

    Muguruma, Kyohei; Yakushiji, Fumika; Kawamata, Ryosuke; Akiyama, Daichi; Arima, Risako; Shirasaka, Takuya; Kikkawa, Yamato; Taguchi, Akihiro; Takayama, Kentaro; Fukuhara, Takeshi; Watabe, Tetsuro; Ito, Yuji; Hayashi, Yoshio

    2016-07-20

    Although several approaches for making antibody-drug conjugates (ADC) have been developed, it has yet to be reported that an antibody binding peptide such as Z33 from protein A is utilized as the pivotal unit to generate the noncovalent-type ADC (NC-ADC). Herein we aim to establish a novel probe for NC-ADC by synthesizing the Z33-conjugated antitumor agent, plinabulin. Due to the different solubility of two components, including hydrophobic plinabulin and hydrophilic Z33, an innovative method with a solid-supported disulfide coupling reagent is required for the synthesis of the target compounds with prominent efficiency (29% isolated yield). We demonstrate that the synthesized hybrid exhibits a binding affinity against the anti-HER2 antibody (Herceptin) and the anti-CD71 antibody (6E1) (Kd = 46.6 ± 0.5 nM and 4.5 ± 0.56 μM, respectively) in the surface plasmon resonance (SPR) assay. In the cell-based assays, the hybrid provides a significant cytotoxicity in the presence of Herceptin against HER2 overexpressing SKBR-3 cells, but not against HER2 low-expressing MCF-7 cells. Further, it is noteworthy that the hybrid in combination with Herceptin induces cytotoxicity against Herceptin-resistant SKBR-3 (SKBR-3HR) cells. Similar results are obtained with the 6E1 antibody, suggesting that the synthesized hybrid can be widely applicable for NC-ADC using the antibody of interest. In summary, a series of evidence presented here strongly indicate that NC-ADCs have high potential for the next generation of antitumor agents. PMID:27304609

  16. Hydrogen bonded supra-molecular framework in inorganic-organic hybrid compounds: Syntheses, structures, and photoluminescent properties

    NASA Astrophysics Data System (ADS)

    Yan, Li; Liu, Wei; Li, Chuanbi; Wang, Yifei; Ma, Li; Dong, Qinqin

    2013-03-01

    Two novel compounds constructed from aromatic acid and N-Heterocyclic ligands have been synthesized by hydrothermal reaction: [Cd(mip)(1,8-NDC)(H2O)]2 (1) [mip = 2-(3-methoxyphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, 1,8-NDC = naphthalene-1,8-dicarboxylic acid] and Cd(mip)2(NTC)2 (2) [NTC = nicotinic acid]. Compounds 1 and 2 are characterized by elemental analysis, IR, single crystal X-ray diffraction and thermogravimetric analysis (TGA). Single-crystal X-ray investigation reveals that compounds 1-2 are 0 dimensional (0D) structures, and the existence of hydrogen bonds and π-π interactions lead the 0D to 2D novel framework. Hydrogen bonds and π-π interactions are powerful non-covalent intermolecular interactions for directing supra-molecular architectures. TG analysis shows clear courses of weight loss, which corresponds to the decomposition of different ligands. At room temperature, compound 1 exhibits emission at 449 nm upon excitation at 325 nm, and compound 2 shows a strong emission at 656 nm upon excitation at 350 nm. Fluorescent spectrum displays that compounds 1 and 2 are potential luminescent materials.

  17. Synthesis and biological effects of new hybrid compounds composed of benzylguanidines and the alkylating group of busulfan on neuroblastoma cells.

    PubMed

    Hampel, Thomas; Bruns, Marietta; Bayer, Melanie; Handgretinger, Rupert; Bruchelt, Gernot; Brückner, Reinhard

    2014-06-15

    (131)Iodine-labelled (meta-iodobenzyl)guanidine ([(131)I]-mIBG) and busulfan [butane-1,4-diylbis(methanesulfonate)] are well-established pharmaceuticals in neuroblastoma therapy. We report the design, synthesis, and testing of hybrid molecules-mBBG and pBBG-which combine key structural features of (meta-iodobenzyl)guanidine and busulfan: they contain a benzylguanidine moiety for accumulating in neuroblastoma cells via the noradrenaline transporter and, in the meta- or para-position, respectively, one of the two identical alkylating motives of busulfan for killing cells. Uptake and toxicity of hybrids mBBG and pBBG in human neuroblastoma cells compared favorably to their ancestors [(131)I]-mIBG and busulfan. PMID:24814532

  18. B-C-N Compounds with Mixed Hybridization of sp2-Like and sp3-Like Bonds

    NASA Astrophysics Data System (ADS)

    Luo, Xiao-Guang; He, Ju-Long

    2012-03-01

    We perform first-principles calculations of the structural and electronic properties of hypothetical bc6-BC4N and N-substituted bc6-BC4N, which are derived from a body-center-cubic carbon structure. Our calculations show that the former is a semiconductor with an indirect band gap of 0.91 eV and the latter is metallic. The calculated bond length, bond population, and charge density of N-substituted bc6-BC4N indicate that one C-N bond has been broken after N-substitution, which means that the structure contains a mixed hybridization of sp2-like and sp3-like bonds. At the pressure above 100 GPa, the structure changes to a pure sp3-like hybridization.

  19. Design, synthesis and anticonvulsant activity of new hybrid compounds derived from N-phenyl-2-(2,5-dioxopyrrolidin-1-yl)-propanamides and -butanamides.

    PubMed

    Kamiński, Krzysztof; Rapacz, Anna; Filipek, Barbara; Obniska, Jolanta

    2016-07-01

    The focused library of 21 new N-phenyl-2-(2,5-dioxopyrrolidin-1-yl)propanamide, 2-(3-methyl-2,5-dioxopyrrolidin-1-yl)propanamide, and 2-(2,5-dioxopyrrolidin-1-yl)butanamide derivatives as potential new hybrid anticonvulsant agents was synthesized. These hybrid molecules were obtained as close analogs of previously described N-benzyl derivatives and fuse the chemical fragments of clinically relevant antiepileptic drugs such as ethosuximide, levetiracetam, and lacosamide. The initial anticonvulsant screening was performed in mice (ip) using the 'classical' maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) tests, as well as in the six-Hertz (6Hz) model of pharmacoresistant limbic seizures. Applying the rotarod test, the acute neurological toxicity was determined. The broad spectra of activity across the preclinical seizure models in mice (ip) displayed compounds 4, 5, 11, and 19. The most favorable anticonvulsant properties demonstrated 4 (ED50 MES=96.9mg/kg, ED50scPTZ=75.4mg/kg, ED50 6Hz=44.3mg/kg) which showed TD50=335.8mg/kg in the rotarod test that yielded satisfying protective indexes (PI MES=3.5, PI scPTZ=4.4, PI 6Hz=7.6). Consequently, compound 4 revealed comparable or better safety profile than model antiepileptic drugs (AEDs): ethosuximide, lacosamide, and valproic acid. In the in vitro assays, compound 4 was observed as relatively effective binder to the neuronal voltage-sensitive sodium and diltiazem site of L-type calcium channels. PMID:27211245

  20. Characterization of organic-inorganic hybrid layered perovskite and intercalated compound (n-C12H25NH3)2ZnCl4

    NASA Astrophysics Data System (ADS)

    Abdel-Kader, M. M.; Aboud, A. I.; Gamal, W. M.

    2016-05-01

    We report on some electrical properties and solid-solid phase transitions of organic-inorganic hybrid layered halide perovskite and intercalated compound (n-C12H25NH3)2ZnCl4 which is one member of the long-chain compounds of the series (n-CnH2n+1NH3)2,(n = 8-18). The complex dielectric permittivity ɛ*(ω,T) and the ac conductivity σ (ω,T) were measured as functions of temperature 100 K < T < 390 K and frequency 5 kHz < f < 100 kHz. Moreover, the differential scanning calorimetery and the differential thermal analysis thermograms were performed. The analysis of our data confirms the existence of a structural phase transition at T ≈ (362 ± 2) K, where the compound changes its state from intercalation to non-intercalation with a drastic increase in the c-axis by about 16.4%. The behavior of the frequency-dependent conductivity follows the Jonscher universal power law: σ (ω, T) αῳs(ῳ,T). The mechanism of electrical conduction in the low-temperature phase (phase II) can be described as quantum mechanical tunneling model.

  1. Bidirectional quantum teleportation of unknown photons using path-polarization intra-particle hybrid entanglement and controlled-unitary gates via cross-Kerr nonlinearity

    NASA Astrophysics Data System (ADS)

    Heo, Jino; Hong, Chang-Ho; Lim, Jong-In; Yang, Hyung-Jin

    2015-05-01

    We propose an arbitrary controlled-unitary (CU) gate and a bidirectional quantum teleportation (BQTP) scheme. The proposed CU gate utilizes photonic qubits (photons) with cross-Kerr nonlinearities (XKNLs), X-homodyne detectors, and linear optical elements, and consists of the consecutive operation of a controlled-path (C-path) gate and a gathering-path (G-path) gate. It is almost deterministic and feasible with current technology when a strong coherent state and weak XKNLs are employed. Based on the CU gate, we present a BQTP scheme that simultaneously teleports two unknown photons between distant users by transmitting only one photon in a path-polarization intra-particle hybrid entangled state. Consequently, it is possible to experimentally implement BQTP with a certain success probability using the proposed CU gate. Project supported by the Ministry of Science, ICT&Future Planning, Korea, under the C-ITRC (Convergence Information Technology Research Center) Support program (NIPA-2013-H0301-13-3007) supervised by the National IT Industry Promotion Agency.

  2. Hybridizing cross-polarization with NOE or refocused-INEPT enhances the sensitivity of MAS NMR spectroscopy.

    PubMed

    Zhang, Rongchun; Mroue, Kamal H; Ramamoorthy, Ayyalusamy

    2016-05-01

    Heteronuclear cross polarization (CP) has been commonly used to enhance the sensitivity of dilute low-γ nuclei in almost all solid-state NMR experiments. However, CP relies on heteronuclear dipolar couplings, and therefore the magnetization transfer efficiency becomes inefficient when the dipolar couplings are weak, as is often the case for mobile components in solids. Here, we demonstrate methods that combine CP with heteronuclear Overhauser effect (referred to as CP-NOE) or with refocused-INEPT (referred to as CP-RINEPT) to overcome the efficiency limitation of CP and enhance the signal-to-noise ratio (S/N) for mobile components. Our experimental results reveal that, compared to the conventional CP, significant S/N ratio enhancement can be achieved for resonances originating from mobile components, whereas the resonance signals associated with rigid groups are not significantly affected due to their long spin-lattice relaxation times. In fact, the S/N enhancement factor is also dependent on the temperature, CP contact time as well as on the system under investigation. Furthermore, we also demonstrate that CP-RINEPT experiment can be successfully employed to independently detect mobile and rigid signals in a single experiment without affecting the data collection time. However, the resolution of CP spectrum obtained from the CP-RINEPT experiment could be slightly compromised by the mandatory use of continuous wave (CW) decoupling during the acquisition of signals from rigid components. In addition, CP-RINEPT experiment can be used for spectral editing utilizing the difference in dynamics of different regions of a molecule and/or different components present in the sample, and could also be useful for the assignment of resonances from mobile components in poorly resolved spectra. Therefore, we believe that the proposed approaches are beneficial for the structural characterization of multiphase and heterogeneous systems, and could be used as a building block in

  3. Hybridizing cross-polarization with NOE or refocused-INEPT enhances the sensitivity of MAS NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Mroue, Kamal H.; Ramamoorthy, Ayyalusamy

    2016-05-01

    Heteronuclear cross polarization (CP) has been commonly used to enhance the sensitivity of dilute low-γ nuclei in almost all solid-state NMR experiments. However, CP relies on heteronuclear dipolar couplings, and therefore the magnetization transfer efficiency becomes inefficient when the dipolar couplings are weak, as is often the case for mobile components in solids. Here, we demonstrate methods that combine CP with heteronuclear Overhauser effect (referred to as CP-NOE) or with refocused-INEPT (referred to as CP-RINEPT) to overcome the efficiency limitation of CP and enhance the signal-to-noise ratio (S/N) for mobile components. Our experimental results reveal that, compared to the conventional CP, significant S/N ratio enhancement can be achieved for resonances originating from mobile components, whereas the resonance signals associated with rigid groups are not significantly affected due to their long spin-lattice relaxation times. In fact, the S/N enhancement factor is also dependent on the temperature, CP contact time as well as on the system under investigation. Furthermore, we also demonstrate that CP-RINEPT experiment can be successfully employed to independently detect mobile and rigid signals in a single experiment without affecting the data collection time. However, the resolution of CP spectrum obtained from the CP-RINEPT experiment could be slightly compromised by the mandatory use of continuous wave (CW) decoupling during the acquisition of signals from rigid components. In addition, CP-RINEPT experiment can be used for spectral editing utilizing the difference in dynamics of different regions of a molecule and/or different components present in the sample, and could also be useful for the assignment of resonances from mobile components in poorly resolved spectra. Therefore, we believe that the proposed approaches are beneficial for the structural characterization of multiphase and heterogeneous systems, and could be used as a building block in

  4. Polybenzimidazole compounds

    DOEpatents

    Klaehn, John R.; Peterson, Eric S.; Wertsching, Alan K.; Orme, Christopher J.; Luther, Thomas A.; Jones, Michael G.

    2010-08-10

    A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

  5. Polar organic compounds in pore waters of the Chesapeake Bay impact structure, Eyreville core hole: Character of the dissolved organic carbon and comparison with drilling fluids

    USGS Publications Warehouse

    Rostad, C.E.; Sanford, W.E.

    2009-01-01

    Pore waters from the Chesapeake Bay impact structure cores recovered at Eyreville Farm, Northampton County, Virginia, were analyzed to characterize the dissolved organic carbon. After squeezing or centrifuging, a small volume of pore water, 100 ??L, was taken for analysis by electrospray ionization-mass spectrometry. Porewater samples were analyzed directly without filtration or fractionation, in positive and negative mode, for polar organic compounds. Spectra in both modes were dominated by low-molecular-weight ions. Negative mode had clusters of ions differing by -60 daltons, possibly due to increasing concentrations of inorganic salts. The numberaverage molecular weight and weight-average molecular weight values for the pore waters from the Chesapeake Bay impact structure are higher than those reported for other aquatic sources of natural dissolved organic carbon as determined by electrospray ionization-mass spectrometry. In order to address the question of whether drilling mud fluids may have contaminated the pore waters during sample collection, spectra from the pore waters were compared to spectra from drilling mud fluids. Ions indicative of drilling mud fluids were not found in spectra from the pore waters, indicating there was no detectable contamination, and highlighting the usefulness of this analytical technique for detecting potential contamination during sample collection. ?? 2009 The Geological Society of America.

  6. Characterization of aerosol associated non-polar organic compounds using TD-GC-MS: a four year study from Delhi, India.

    PubMed

    Yadav, Shweta; Tandon, Ankit; Attri, Arun K

    2013-05-15

    Aerosol associated Non-Polar Organic Compounds (NPOCs)--25 n-alkanes, 17 Polycyclic Aromatic Hydrocarbons (PAHs), and 3 Isoprenoid hydrocarbons--have been identified and quantified in PM10 samples collected over four years in time sequence (2006-2009), using Thermal Desorption Gas Chromatography Mass Spectrometry, in Delhi region. Established organic markers, associated diagnostic parameters, and molecular diagnostic ratios were used to assess and discern the contributing biogenic, petrogenic and pyrogenic sources to NPOCs. Analysis show that anthropogenic contributions to NPOCs exhibit increase from 2006 to 2009. Distribution profiles of NPOCs were significantly affected by change in season. Lower concentrations of NPOCs during summer months, and higher during winter, once scaled to Planetary Boundary Layer height, suggests that contributing sources were most active during summer months. During monsoon season high mass fractions of Total n-alkanes (ppm), Total PAHs (ppm), and Black carbon (BC) % alludes at the role of differential washout process involving hydrophilic and hydrophobic fractions of ambient aerosols. Significantly high, four year average concentrations of TPAH and BC signify the dominance of pyrogenic source contributions to PM10. High correlation between monthly mean concentrations of TPAH and BC (R(2)=0.75) suggests that besides common emission source, they are also contributed, individually, by exclusive independent sources. PMID:23500789

  7. [Polar neutral organic compounds (POCN) in city aerosols. 2. Measuring of emissions from domestic fuel and vehicle exhaust and from immission particles in Berlin (West)].

    PubMed

    Moriske, H J; Freise, R; Schneider, C; Rüden, H

    1987-10-01

    During April and May 1985, some emission samples from private coal firing (domestic fuel) were taken and were fired with two different kind of coal (bituminous and brown coal). Also, measurements were done under different combustion conditions (low and high concentrations of oxygenium during the combustion process). In June and November 1985, some emission samples from heavy diesel-engines were taken in a special tunnel equipment, at different engine conditions. During September 1985, also suspended particulates in a highway traffic tunnel were taken. All these samples were taken using high volume cascade impactors which give a fractionation of the suspended particulates into different particle sizes, according to their retention behaviour in the human respiratory system. The results of these emission samples and samples in the highway tunnel were compared with prior immission measurements of urban suspended particulates in Berlin-West, during January 1984. The etherextractable organic matter (= EEOM) of the total suspended particulate matter (= TPM) was determined using ultrasonic extraction method. The EEOM was separated into an acidic (= AF), a basic (= BF) and a neutral fraction (= NF) by dissolution in acidic and basic agents. Of the neutral fraction (NF), further separation was done into aliphatic compounds (= AIP), polycyclic aromatic hydrocarbons (= PAH) and polar neutral organic compounds (POCN) by using thin layer chromatography. From the PAH and POCN, single compounds were identified by gas chromatographic analysis with dual capillary collumns and internal standard method. All organic fractions were tested to their mutagenic activity in the Salmonella typhimurium mammalian microsome bioassay by Ames. The following results were gained: the neutral fraction (NF) made the highest part of the EEOM (greater than or equal to 60%) whereas the part of the AF amounted to 10-25% and of the basic fraction (BF) to approximatively 5-20%. Making further separation of

  8. Hybrid compounds of Keggin polyoxotungstate with transition metal ion as the central atom. Synthesis, structure and properties

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Min; Chen, Ya-Guang; Shi, Tian

    2016-02-01

    The compounds (Hbipy)2[Co(bipy)2(H2O)4]2(CoW12O40)·2bipy·7H2O (1) and [Ni2(Hbipy)2(bipy)(H2O)4(H2W12O40)]·5H2O (2) (bipy = 4,4-bipyridine) were synthesized hydrothermally and characterized by elemental analysis, IR spectroscopy, TG analyses, solid ultraviolet diffuse spectroscopy and single crystal X-ray diffraction method. In 1 the complex ions, [Co(bipy)2(H2O)4]2+, construct a supramolecular layer through π-π stacking interaction. The heteropolyanions with central Co atom and supramolecular layers are linked by hydrogen bonds. In 2 a 2D structure is formed from metatungstate anions and binuclear Ni-bipy complexes through the coordination of metatungstate anions and bipy to Ni ions. Between the layers and bipyridine molecules are the hydrogen bond interactions. The formation of 1 and 2 shows that the solution acidity and metal ions influence greatly the structure of the compounds. Solid ultraviolet diffusion results indicate that the compounds 1 and 2 are potential semiconductor materials. In 1 and 2 there exists a weak antiferromagnetic interaction.

  9. Polyoxometalate-based organic-inorganic hybrid compounds containing transition metal mixed-organic-ligand complexes of N-containing and pyridinecarboxylate ligands.

    PubMed

    Zhao, De-Chuan; Hu, Yang-Yang; Ding, Hong; Guo, Hai-Yang; Cui, Xiao-Bing; Zhang, Xiao; Huo, Qi-Sheng; Xu, Ji-Qing

    2015-05-21

    Five new organic–inorganic hybrid compounds based on the Keggin-type polyoxoanion [SiW12O40]4−, namely [Cu3(2,2′-bpy)3(inic)(μ2-OH)(H2O)][SiW12O40]·2H2O (1), [Cu6(phen)6(μ3-Cl)2(μ2-Cl)2Cl2(inic)2][SiW12O40]·6H2O (2), [Cu2(hnic)(2,2′-bpy)2Cl]2[H2SiW12O40] (3), [Cu2(nic)(phen)2Cl2]2[SiW12O40] (4) and [Cu2(pic)(2,2′-bpy)2Cl]2[SiW12O40] (5) (inic = isonicotinic acid, hnic = 2-hydroxy-nicotinic acid, nic = nicotinic acid, pic = picolinic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) have been synthesized and characterized by IR, UV-Vis, XPS, XRD, cyclic voltammetric measurements, photoluminescence analysis and single crystal X-ray diffraction analysis. Crystal analysis reveals that compound 1 exhibits a 2-D double layered framework structure constructed from [SiW12O40]4− and copper-aqua-2,2′-bipy-hydroxyl-isonicotinate complexes. Compound 2 is a 0-D discrete structure formed by [SiW12O40]4− and copper-chloro-isonicotinate-phenanthroline complexes. Compound 3 shows a 1-D single chain structure based on the linkage of copper-2,2-bpy-chloro-2-hydroxy-nicotinate complexes and [SiW12O40]4−. Compounds 4 and 5 both contain polyoxometalate supported transition metal complexes, one is a polyoxometalate supported copper-chloro-nicotinate-phenanthroline complex in 4, and the other is a polyoxometalate supported copper-2,2-bpy-chloro-nicotinate complex in 5. It should be noted that nicotinic, isonicotinic and picolinic acids are structural isomers and 2-hydroxy-nicotinic acid is an in situ hydroxylated product of nicotinic acid. In addition, photocatalytic degradation of Rhodamine B (RhB) by compounds 1–5 has been investigated in aqueous solutions. PMID:25882351

  10. A new hybrid constructed from Dawson-like polyoxometalates and dicopper coordination compounds containing a discrete tridecameric water cluster

    NASA Astrophysics Data System (ADS)

    Yang, Hongxun; Cao, Minna; Gao, Shuiying; Cao, Rong

    2014-01-01

    A new organic-inorganic hybrid polyoxotungstates, [Cu2Cl(H2O)3(phen)2]2[H3SbW18O60]·7H2O (phen = 1,10-phenanthroline, 1), has been synthesized and characterized by elemental analyses, FTIR, TG, UV-DRS, XRPD, magnetic property and X-ray single crystal diffraction. The structure analyses reveal that complex 1 based on Dawson-like polyoxoanions and dicopper coordination cations exhibits 3D supramolecular network via hydrogen bonding and π-π stacking containing a new discrete tridecameric water cluster. The magnetic property of 1 was also investigated between 2 and 300 K, indicating the existence of antiferromagnetic exchange interaction between the Cu(II) centres.

  11. Weak hybridization and isolated localized magnetic moments in the compounds CeT2Cd20 (T = Ni, Pd)

    SciTech Connect

    White, B. D.; Yazici, D.; Ho, P. -C.; Kanchanavatee, N.; Pouse, N.; Fang, Y.; Breindel, A. J.; Friedman, A. J.; Maple, M. B.

    2015-07-20

    Here, we report the physical properties of single crystals of the compounds CeT2Cd20 (T = Ni, Pd) that were grown in a molten Cd flux. Large separations of ~6.7- 6.8 Å between Ce ions favor the localized magnetic moments that are observed in measurements of the magnetization. The strength of the Ruderman-Kittel-Kasuya- Yosida magnetic exchange interaction between the localized moments is severely limited by the large Ce-Ce separations and by weak hybridization between localized Ce 4f and itinerant electron states. Measurements of electrical resistivity performed down to 0.138 K were unable to observe evidence for the emergence of magnetic order; however, magnetically-ordered ground states with very low transition temperatures are still expected in these compounds despite the isolated nature of the localized magnetic moments. Such a fragile magnetic order could be highly susceptible to tuning via applied pressure, but evidence for the emergence of magnetic order has not been observed so far in our measurements up to 2.5 GPa.

  12. Hybrid-integrated polarization mode converters and low-voltage electro-optic modulators using crystal-ion-sliced LiNbO3 films

    NASA Astrophysics Data System (ADS)

    Radojevic, Antonije M.; Fujita, Junichiro; Eldada, Louay A.

    2002-06-01

    Lithium Niobate (LiNbO3) films produced by the crystal ion slicing (CIS) method are introduced in various components in use in the optical telecommunications market. The CIS technique employs high-energy ion implantation to create a narrow (~0.2 micrometers ) planar layer of localized damage, buried ~10 micrometers beneath the surface of the implanted LiNbO3 wafers. This sacrificial layer allows for slicing of microns-thick LiNbO3 films, either by selective wet chemical etching or by thermal shock. The obtained films have bulk material properties and morphology suitable for integrated optics applications. Slices of X-cut LiNbO3 were used to produce zero-order wave retarders that can be inserted in slots cut into planar lightwave circuits, resulting in TE-TM polarization mode conversion with high extinction ratio (30 dB) and low excess loss (<0.1 dB). Conventional LiNbO3 waveguide fabrication techniques were combined with the CIS process to produce CIS films of Z-cut LiNbO3 with optical circuits patterned prior to lift-off, having propagation losses typical of bulk LiNbO3 waveguides. Using thin sheets of LiNbO3, velocity- and impedance-matched modulators can be fabricated with low V(pi )L(~7.6 V.cm) and low microwave losses (0.3 db/cm.GHz1/2). The CIS film optical circuits can be integrated into hybrid systems with otherwise incompatible, yet technologically important materials platforms.

  13. Production of hybrid lipid-based particles loaded with inorganic nanoparticles and active compounds for prolonged topical release.

    PubMed

    García-González, C A; Sampaio da Sousa, A R; Argemí, A; López Periago, A; Saurina, J; Duarte, C M M; Domingo, C

    2009-12-01

    The production of particulate hybrid carriers containing a glyceryl monostearate (Lumulse GMS-K), a waxy triglyceride (Cutina HR), silanized TiO(2) and caffeine were investigated with the aim of producing sunscreens with UV-radiation protection properties. Particles were obtained using the supercritical PGSS (Particles from Gas Saturated Solutions) technique. This method takes advantages of the lower melting temperatures of the lipids obtained from the dissolution of CO(2) in the bulk mixture. Experiments were performed at 13 MPa and 345 K, according to previous melting point measurements. Blends containing Lumulse GMS-K and Cutina HR lipids (50 wt%) were loaded with silanized TiO(2) and caffeine in percentile proportions of 6 and 4 wt%, respectively. The particles produced were characterized using several analytical techniques as follows: system crystallinity was checked by X-ray diffraction and differential scanning calorimetry, thermal stability by thermogravimetric analysis, and morphology by scanning and transmission electron microscopy. Further, the UV-shielding ability of TiO(2) after its dispersion in the lipidic matrix was assessed by solid UV-vis spectroscopy. Preliminary results indicated that caffeine-loaded solid lipid particles presented a two-step dissolution profile, with an initial burst of 60 wt% of the loaded active agent. Lipid blends loaded with TiO(2) and caffeine encompassed the UV-filter behavior of TiO(2) and the photoaging prevention properties of caffeine. PMID:19720123

  14. Simultaneous detection of polar and nonpolar compounds by ambient mass spectrometry with a dual electrospray and atmospheric pressure chemical ionization source.

    PubMed

    Cheng, Sy-Chyi; Jhang, Siou-Sian; Huang, Min-Zong; Shiea, Jentaie

    2015-02-01

    A dual ionization source combining electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) was developed to simultaneously ionize both polar and nonpolar compounds. The source was constructed by inserting a fused silica capillary into a stainless steel column enclosed in a glass tube. A high dc voltage was applied to a methanol solution flowing in the fused silica capillary to generate an ESI plume at the capillary tip. A high ac voltage was applied to a ring electrode attached to the glass tube to generate plasma from the nitrogen gas flowing between the glass tube and the stainless steel column. The concentric arrangement of the ESI plume and the APCI plasma in the source ensured that analytes entering the ionization region interacted with both ESI and APCI primary ion species generated in the source. Because the high voltages required for ESI and APCI were independently applied and controlled, the dual ion source could be operated in ESI-only, APCI-only, or ESI+APCI modes. Analytes were introduced into the ESI and/or APCI plumes by irradiating sample surfaces with a continuous-wavelength laser or a pulsed laser beam. Analyte ions could also be produced by directing the dual ESI+APCI source toward sample surfaces for desorption and ionization. The ionization mechanisms involved in the dual ion source include Penning ionization, ion molecule reactions, and fused-droplet electrospray ionization. Standards of polycyclic aromatic hydrocarbons, angiotensin I, lidocaine, ferrocene, diesel, and rosemary oils were used for testing. Protonated analyte ions were detected in ESI-only mode, radical cations were detected in APCI-only mode, and both types of ions were detected in ESI+APCI mode. PMID:25562530

  15. Experimental and theoretical study of AC electrical conduction mechanisms of Organic-inorganic hybrid compound Bis (4-acetylanilinium) tetrachlorocadmiate (II)

    NASA Astrophysics Data System (ADS)

    Jellibi, A.; Chaabane, I.; Guidara, K.

    2016-06-01

    A new organic-inorganic bis (4-acetylaniline) tetrachlorocadmate [C8H10NO]2[CdCl4] can be obtained by slow evaporation at room temperature and characterized by X-ray powder diffraction. It crystallized in an orthorhombic system (Cmca space group). The material electrical properties were characterized by impedance spectroscopy technique in the frequency range from 209 Hz-5 MHz and temperature 413 to 460 K. Besides, the impedance plots show semicircle arcs at different temperatures and an electrical equivalent circuit has been proposed to interpret the impedance results. The circuits consist of the parallel combination of a resistance (R), capacitance (C) and fractal capacitance (CPE). The variation of the exponent s as a function of temperature suggested that the conduction mechanism in Bis (4-acetylanilinium) tetrachlorocadmiate compound is governed by two processes which can be ascribed to a hopping transport mechanism: correlated barrier hopping (CBH) model below 443 K and the small polaron tunneling (SPT) model above 443 K.

  16. Differential profiling of volatile organic compound biomarker signatures utilizing a logical statistical filter-set and novel hybrid evolutionary classifiers

    NASA Astrophysics Data System (ADS)

    Grigsby, Claude C.; Zmuda, Michael A.; Boone, Derek W.; Highlander, Tyler C.; Kramer, Ryan M.; Rizki, Mateen M.

    2012-06-01

    A growing body of discoveries in molecular signatures has revealed that volatile organic compounds (VOCs), the small molecules associated with an individual's odor and breath, can be monitored to reveal the identity and presence of a unique individual, as well their overall physiological status. Given the analysis requirements for differential VOC profiling via gas chromatography/mass spectrometry, our group has developed a novel informatics platform, Metabolite Differentiation and Discovery Lab (MeDDL). In its current version, MeDDL is a comprehensive tool for time-series spectral registration and alignment, visualization, comparative analysis, and machine learning to facilitate the efficient analysis of multiple, large-scale biomarker discovery studies. The MeDDL toolset can therefore identify a large differential subset of registered peaks, where their corresponding intensities can be used as features for classification. This initial screening of peaks yields results sets that are typically too large for incorporation into a portable, electronic nose based system in addition to including VOCs that are not amenable to classification; consequently, it is also important to identify an optimal subset of these peaks to increase classification accuracy and to decrease the cost of the final system. MeDDL's learning tools include a classifier similar to a K-nearest neighbor classifier used in conjunction with a genetic algorithm (GA) that simultaneously optimizes the classifier and subset of features. The GA uses ROC curves to produce classifiers having maximal area under their ROC curve. Experimental results on over a dozen recognition problems show many examples of classifiers and feature sets that produce perfect ROC curves.

  17. A novel approach for identification of biologically active phenolic compounds in complex matrices using hybrid quadrupole-orbitrap mass spectrometer: A promising tool for testing antimicrobial activity of hops.

    PubMed

    Dušek, Martin; Jandovská, Vladimíra; Čermák, Pavel; Mikyška, Alexandr; Olšovská, Jana

    2016-08-15

    The phenolic compounds, secondary metabolites of hops represent a large family of compounds that could be subsequently divided into smaller groups based on the similarities between their chemical structures. The antibacterial, antifungal and antiviral properties of hops are well known, but there is a lack of information about antimicrobial activities of individual hop compounds. This study was carried out with an objective to identify compounds present in hops that have potential antibacterial activity. In the first stage of experiment, the active compounds with potential anti-microbial activity had to be extracted from hop cones. Therefore, minced hop cones were applied on solid growth medium inoculated with Staphylococcus aureus. The active substances that migrated into the medium created an inhibition zone. In the second stage of experiment, the inhibition zones were cut out from Petri dishes, active compounds were extracted from these zones and consequently analyzed using LC-HRMS. These complex assays were developed and optimized. The data were acquired by using a quadrupole-orbitrap hybrid mass spectrometer by targeted-MS2 experiment in both ionization modes. The MS method has been developed as a screening method with a subsequent fragmentation of compound of interest on the base of inclusion mass list. The unknown compounds extracted from inhibition zones have been identified either by searching against a database or their structure has been elucidated on the basis of their fragmentation spectra. On the basis of this experiment the list of active compounds with potential anti-microbial activities was enhanced. PMID:27260455

  18. Long-term nitrogen compound removal trends of a hybrid subsurface constructed wetland treating milking parlor wastewater throughout its 7 years of operation.

    PubMed

    Harada, J; Inoue, T; Kato, K; Izumoto, H; Zhang, X; Sakuragi, H; Wu, D; Ietsugu, H; Sugawara, Y

    2016-01-01

    This study evaluated the nitrogen compound removal efficiency of a hybrid subsurface constructed wetland, which began treating milking parlor wastewater in Hokkaido, northern Japan, in 2006. The wetland's overall removal rates of total nitrogen (TN) and ammonium (NH4(+)-N) improved after the second year of operation, and its rate of organic nitrogen (Org-N) removal was stable at 90% efficiency. Only nitrate (NO3(-)-N) levels were increased following the treatment. Despite increased NO3(-)-N (maximum of 3 mg-N/L) levels, TN removal rates were only slightly affected. Removal rates of TN and Org-N were highest in the first vertical bed. NH4(+)-N removal rates were highest in the second vertical bed, presumably due to water recirculation and pH adjustment. Concentrations of NO3(-)-N appeared when total carbon (TC) levels were low, which suggests that low TC prevented complete denitrification in the second vertical bed and the final horizontal bed. In practice, the beds removed more nitrogen than the amount theoretically removed by denitrification, as calculated by the amount of carbon removed from the system. This carbon-nitrogen imbalance may be due to other nitrogen transformation mechanisms, which require less carbon. PMID:26942522

  19. Evaluation of the magnetic coupling degree and performance of an axial-axial flux compound-structure permanent-magnet synchronous machine used for hybrid electric vehicles

    NASA Astrophysics Data System (ADS)

    Zheng, Ping; Zhao, Jing; Wu, Qian; Fan, Weiguang; Shen, Lin; Li, Lina; Liu, Ranran

    2008-04-01

    A novel axial-axial flux compound-structure permanent-magnet synchronous machine (CS-PMSM), which is a hybrid electric vehicle (HEV) power train concept, is integrated by two axial flux disk machines. As the two machines share a common rotor [a magnet rotor with permanent magnets (PMs) on both sides], there may be magnetic coupling between them. Three-dimensional (3D) finite-element method (FEM) calculation shows that the two machines have little magnetic coupling if they have the same pole number and consistent magnetization direction of the two layers of PMs on the common rotor. The performance of the CS-PMSM is evaluated on criteria such as power, power per unit volume and mass, torque, and torque ripple. The power and torque equations of this type of machine are deduced and verified with 3D FEM. After the optimization of diameter ratio and pole number, the power and power per unit active volume and mass are high. The torque ripple is much reduced due to the optimization of the pole arc embrace and magnet skewing angle.

  20. Evaluation of performance and magnetic characteristics of a radial-radial flux compound-structure permanent-magnet synchronous machine used for hybrid electric vehicle

    NASA Astrophysics Data System (ADS)

    Zheng, Ping; Liu, Ranran; Shen, Lin; Li, Lina; Fan, Weiguang; Wu, Qian; Zhao, Jing

    2008-04-01

    A breed of compound-structure permanent-magnet synchronous machine (CS-PMSM) is used for power-split hybrid electric vehicles (HEVs). It can help to fulfill both the speed and torque control of the internal combustion engine and, thus, realize the optimum operation of the HEV. In this paper, a radial-radial flux CS-PMSM, which is integrated by two machines radially [one stator machine (SM) and one double-rotor machine (DRM)], is designed and investigated. The machine performance is evaluated with finite-element method (FEM) and satisfactory results are obtained. The back electromotive force curves of the two machines are somewhat similar to sinusoidal ones; the average torques both meet the requirements; and due to the adoption of skewed slots, the cogging torques and torque ripples are quite small. The inductance parameter is calculated with a phasor diagram based two-dimensional FEM and the magnetic saturation and cross-magnetization effect are discussed. It is concluded that the SM is slightly saturated with no or little cross-magnetization phenomenon, whereas the DRM has deep-degree magnetic saturation and the cross-magnetization effect is notable.

  1. Polar organic marker compounds in atmospheric aerosol in the Po Valley during the Supersito campaigns - Part 1: Low molecular weight carboxylic acids in cold seasons

    NASA Astrophysics Data System (ADS)

    Pietrogrande, Maria Chiara; Bacco, Dimitri; Visentin, Marco; Ferrari, Silvia; Poluzzi, Vanes

    2014-04-01

    In the framework of the “Supersito” project, three intensive experimental campaigns were conducted in the Po Valley (Northern Italy) in cold seasons, such as late autumn, pre-winter and deep-winter, over three years from 2011 to 2013. As a part of a study on polar marker compounds, including carboxylic acids, sugar derivatives and lignin phenols, the present study reports a detailed discussion on the atmospheric concentrations of 14 low molecular weight carboxylic acids, mainly dicarboxylic and oxo-hydroxy carboxylic acids, as relevant markers of primary and secondary organic aerosols. PM2.5 samples were collected in two monitoring sites, representing urban and rural background stations. The total quantities of carboxylic acids were 262, 167 and 249 ng m-3 at the urban site and 308, 115, 248 ng m-3 at the rural site in pre-winter, fall and deep-winter, respectively. These high concentrations can be explained by the large human emission sources in the urbanized region, combined with the stagnant atmospheric conditions during the cold seasons that accumulate the organic precursors and accelerate the secondary atmospheric reactions. The distribution profiles of the investigated markers suggest the dominant contributions of primary anthropogenic sources, such as traffic, domestic heating and biomass burning. These results are confirmed by comparison with additional emission tracers, such as anhydro-saccharides for biomass burning and fatty acids originated from different anthropogenic sources. In addition, some secondary constituents were detected in both sites, as produced by in situ photo-chemical reactions from both biogenic (e.g. pinonic acid) and anthropogenic precursors (e.g. phthalic and adipic acids). The impact of different sources from human activities was elucidated by investigating the week pattern of carboxylic and fatty acid concentrations. The weekly trends of analytes during the warmer campaign (fall 2012; mean temperature: 12 °C) may be related to

  2. Coumarin-Chalcone Hybrids as Peroxyl Radical Scavengers: Kinetics and Mechanisms.

    PubMed

    Mazzone, Gloria; Galano, Annia; Alvarez-Idaboy, Juan R; Russo, Nino

    2016-04-25

    The primary antioxidant activity of coumarin-chalcone hybrids has been investigated using the density functional and the conventional transition state theories. Their peroxyl radical scavenging ability was studied in solvents of different polarity and taking into account different reaction mechanisms. It was found that the activity of the hybrids increases with the polarity of the environment and the number of phenolic sites. In addition, their peroxyl radical scavenging activity is larger than those of the corresponding nonhybrid coumarin and chalcone molecules. This finding is in line with previous experimental evidence. All the investigated molecules were found to react faster than Trolox with (•)OOH, regardless of the polarity of the environment. The role of deprotonation on the overall activity of the studied compounds was assessed. The rate constants and branching ratios for the reactions of all the studied compounds with (•)OOH are reported for the first time. PMID:26998844

  3. 4,5-Diaryl-3H-1,2-dithiole-3-thiones and related compounds as combretastatin A-4/oltipraz hybrids: Synthesis, molecular modelling and evaluation as antiproliferative agents and inhibitors of tubulin.

    PubMed

    Wang, Zhiwei; Qi, Huan; Shen, Qirong; Lu, Guodong; Li, Mingyang; Bao, Kai; Wu, Yingliang; Zhang, Weige

    2016-10-21

    A new series of 4,5-diaryl-3H-1,2-dithiole-3-thiones and related compounds were designed and synthesised as combretastatin A-4/oltipraz hybrids. We evaluated the antiproliferative activities, inhibition of tubulin polymerization, and cell-cycle effects of these compounds. Several compounds in this series, such as 4d and 5c, displayed significant activity against SGC-7901, KB and HT-1080 cell lines, as determined using MTT assays. The most active compound, 4d, markedly inhibited tubulin polymerization, with an IC50 value of 4.44 μM being observed. In mechanistic studies, 4d caused cell arrest in G2/M phase, induced apoptotic cell death, and disrupted microtubule formation. Molecular docking studies revealed that 4d interacts and binds efficiently with the tubulin protein. PMID:27428395

  4. Glassy polarization behavior in ferroelectric compounds Pb(Mg{1}/{3}Nb{2}/{3}) O3 and Pb(Zn{1}/{3}Nb{2}/{3}) O3

    NASA Astrophysics Data System (ADS)

    Burns, Gerald; Dacol, F. H.

    1983-12-01

    We report measurements of the temperature dependence of the optic index of refraction, n(T), at several wave lengths in two ferroelectric compounds that have the simple perovskite ABO 3 structure. The compounds are Pb(Mg{1}/{3}Nb{2}/{3}) O3 and Pb(Zn{1}/{3}Nb{2}/{3}) O3 where the B-site ions are disordered. Deviations from the high temperature linear n(T) can be observed starting at a temperature T d (far above the ferroelectric phase transition temperature T c). We assume a model in which these deviations arise from very local randomly oriented polarization (i.e. glassy polarization), P d. Then, using the quadratic electrooptic effect and the known coefficients, we determine P d and compare it to the normally observed ferroelectric reversible spontaneous polarization P r. Also, from infrared reflectivity data, we show that these materials are microscopically homogeneous. We believe that our model of the phase transition contains the basic physics describing ferroelectrics with diffuse phase transitions.

  5. Hybrid organic PVDF-inorganic M-rGO-TiO2 (M = Ag, Pt) nanocomposites for multifunctional volatile organic compound sensing and photocatalytic degradation-H2 production

    NASA Astrophysics Data System (ADS)

    Ong, W. L.; Gao, M.; Ho, G. W.

    2013-10-01

    This work focused on the development of a hybrid organic-inorganic TiO2 nanocomposite, which demonstrates the first ever report on harmful volatile organic compound (VOC) sensing and photocatalytic degradation-H2 production. The sensing and photocatalytic properties are enhanced by the synergetic effects of well-structured TiO2 nanotubes, metal nanoparticles and reduced graphene oxide loading for enhanced light absorption and charge-transfer kinetics. Hybridization of a functionalized TiO2 nanocomposite with a polyvinylidene fluoride (PVDF) matrix induced strong cross-linking networks between the inorganic-organic components, which promote mechanical reinforcement-flexibility and highly porous asymmetric structures. The developed solution processable nanocomposite has immense potential to remedy the global environmental and energy issues by producing clean water/air and energy from organic compound waste.This work focused on the development of a hybrid organic-inorganic TiO2 nanocomposite, which demonstrates the first ever report on harmful volatile organic compound (VOC) sensing and photocatalytic degradation-H2 production. The sensing and photocatalytic properties are enhanced by the synergetic effects of well-structured TiO2 nanotubes, metal nanoparticles and reduced graphene oxide loading for enhanced light absorption and charge-transfer kinetics. Hybridization of a functionalized TiO2 nanocomposite with a polyvinylidene fluoride (PVDF) matrix induced strong cross-linking networks between the inorganic-organic components, which promote mechanical reinforcement-flexibility and highly porous asymmetric structures. The developed solution processable nanocomposite has immense potential to remedy the global environmental and energy issues by producing clean water/air and energy from organic compound waste. Electronic supplementary information (ESI) available: Digital photographs illustrating color change during photoreduction of GO (Fig. S1). See DOI: 10.1039/c3nr

  6. Sol-gel encapsulation of binary Zn(II) compounds in silica nanoparticles. Structure-activity correlations in hybrid materials targeting Zn(II) antibacterial use.

    PubMed

    Halevas, E; Nday, C M; Kaprara, E; Psycharis, V; Raptopoulou, C P; Jackson, G E; Litsardakis, G; Salifoglou, A

    2015-10-01

    In the emerging issue of enhanced multi-resistant properties in infectious pathogens, new nanomaterials with optimally efficient antibacterial activity and lower toxicity than other species attract considerable research interest. In an effort to develop such efficient antibacterials, we a) synthesized acid-catalyzed silica-gel matrices, b) evaluated the suitability of these matrices as potential carrier materials for controlled release of ZnSO4 and a new Zn(II) binary complex with a suitably designed well-defined Schiff base, and c) investigated structural and textural properties of the nanomaterials. Physicochemical characterization of the (empty-loaded) silica-nanoparticles led to an optimized material configuration linked to the delivery of the encapsulated antibacterial zinc load. Entrapment and drug release studies showed the competence of hybrid nanoparticles with respect to the a) zinc loading capacity, b) congruence with zinc physicochemical attributes, and c) release profile of their zinc load. The material antimicrobial properties were demonstrated against Gram-positive (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus) and negative (Escherichia coli, Pseudomonas aeruginosa, Xanthomonas campestris) bacteria using modified agar diffusion methods. ZnSO4 showed less extensive antimicrobial behavior compared to Zn(II)-Schiff, implying that the Zn(II)-bound ligand enhances zinc antimicrobial properties. All zinc-loaded nanoparticles were less antimicrobially active than zinc compounds alone, as encapsulation controls their release, thereby attenuating their antimicrobial activity. To this end, as the amount of loaded zinc increases, the antimicrobial behavior of the nano-agent improves. Collectively, for the first time, sol-gel zinc-loaded silica-nanoparticles were shown to exhibit well-defined antimicrobial activity, justifying due attention to further development of antibacterial nanotechnology. PMID:26198972

  7. Experimental designs dedicated to the evaluation of a membrane extraction method: membrane-assisted solvent extraction for compounds having different polarities by means of gas chromatography-mass detection.

    PubMed

    Vincelet, Carole; Roussel, Jean Marc; Benanou, David

    2010-03-01

    Membrane-assisted solvent extraction was applied for the determination of different classes of compounds in water, having K(o/w) (octanol-water partition coefficient) values between 10(1) (aniline) and 10(8) (methyl stearate), by means of experimental designs. Four solvents were investigated--propan-2-ol, ethyl acetate, diisopropyl ether and cyclohexane--as well as extraction time, temperature, salt impact, pH and methanol addition. The best choice was diisopropyl ether, 50 degrees C, 30 min and an addition of 3 g of sodium chloride at pH 2 for polar compounds. The relative standard deviation (n = 3) was found in the range from 5 to 17%. Recoveries ranged between 34 and 100%. Membrane-assisted solvent extraction was successfully applied to a fast screening method dedicated to an unknown wastewater sample. PMID:20127320

  8. Application of recent double-hybrid density functionals to low-lying singlet-singlet excitation energies of large organic compounds

    NASA Astrophysics Data System (ADS)

    Meo, F. Di; Trouillas, P.; Adamo, C.; Sancho-García, J. C.

    2013-10-01

    The present work assesses some recently developed double-hybrid density functionals (B2π-PLYP, PBE0-DH, and PBE0-2) using linear-response Tamm-Dancoff Time-Dependent Density Functional Theory. This assessment is achieved against experimentally derived low-lying excitation energies of large organic dyes of recent interest, including some excitations dominated by charge-transfer transitions. Comparisons are made with some of the best-performing methods established from the literature, such as PBE0 or B3LYP hybrid or the recently proposed B2-PLYP and B2GP-PLYP double-hybrid models, to ascertain their quality and robustness on equal footing. The accuracy of parameter-free or empirical forms of double-hybrid functionals is also briefly discussed. Generally speaking, it turns out that double-hybrid expressions always provide more accurate estimates than corresponding hybrid methods. Double-hybrid functionals actually reach averaged accuracies of 0.2 eV, that can be admittedly considered close to any intended accuracy limit within the present theoretical framework.

  9. The use of a housecleaning product in an indoor environment leading to oxygenated polar compounds and SOA formation: Gas and particulate phase chemical characterization

    NASA Astrophysics Data System (ADS)

    Rossignol, S.; Rio, C.; Ustache, A.; Fable, S.; Nicolle, J.; Même, A.; D'Anna, B.; Nicolas, M.; Leoz, E.; Chiappini, L.

    2013-08-01

    This work investigates Secondary Organic Aerosol (SOA) formed by limonene ozonolysis using a housecleaning product in indoor environment. This study combines simulation chamber ozonolysis experiments and field studies in an experimental house allowing different scenarios of housecleaning product use in real conditions. Chemical speciation has been performed using a new method based on simultaneous sampling of both gas and particulate phases on sorbent tubes and filters. This method allowed the identification and quantification of about 35 products in the gas and particulate phases. Among them, products known to be specific from limonene ozonolysis such as limononaldehyde, ketolimonene and ketolimonic acid have been detected. Some other compounds such as 2-methylbutanoic acid had never been detected in previous limonene ozonolysis studies. Some compounds like levulinic acid had already been detected but their formation remained unexplained. Potential reaction pathways are proposed in this study for these compounds. For each experiment, chemical data are coupled together with physical characterization of formed particles: mass and size and number distribution evolution which allowed the observation of new particles formation (about 87,000 particle cm-3). The chemical speciation associated to aerosol size distribution results confirmed that limonene emitted by the housecleaning product was responsible for SOA formation. To our knowledge, this work provides the most comprehensive analytical study of detected compounds in a single experiment for limonene ozonolysis in both gaseous and particulate phases in real indoor environment.

  10. Assessment of volatile compounds, neutral and polar lipid fatty acids of four beef muscles from USDA Choice and Select graded carcasses and their relationships with consumer palatability scores and intramuscular fat content.

    PubMed

    Hunt, M R; Legako, J F; Dinh, T T N; Garmyn, A J; O'Quinn, T G; Corbin, C H; Rathmann, R J; Brooks, J C; Miller, M F

    2016-06-01

    Fatty acids (FA) in neutral and polar lipids (NL and PL) and volatile compounds were determined in Gluteus medius (GM), Longissimus lumborum (LL), Serratus ventralis (SV), and Semimembranosus (SM) muscles from upper 2/3 USDA Choice and Select quality grades (QG). Concentrations of NL FA (mg/g) were influenced by intramuscular fat (IMF) content being greater in upper 2/3 Choice compared with Select. The SV contained greater concentrations of NL FA; meanwhile, the SM contained the lowest quantities of NL FA. Percentages (g/100g of total FA) of NL SFA and MUFA were increased in beef with greater IMF content. Concentrations and percentages of PL FA had muscle specific differences between QG. Volatile compounds were primarily affected by muscle. Increases in SFA and MUFA were related with consumer liking, regardless of lipid fraction. Overall the influence of QG on SFA and MUFA was muscle specific. Therefore, each muscle may require specific considerations when considering FA, volatile compounds, and ultimately consumer liking. PMID:26874592

  11. Energetics of nonpolar and polar compounds in cationic, anionic, and nonionic micelles studied by all-atom molecular dynamics simulation combined with a theory of solutions.

    PubMed

    Date, Atsushi; Ishizuka, Ryosuke; Matubayasi, Nobuyuki

    2016-05-21

    Energetic analysis was conducted for nonpolar and polar solutes bound in a cationic micelle of dodecyl trimethyl ammonium bromide (DTAB), an anionic micelle of sodium dodecyl sulfate (SDS), and a nonionic micelle of tetraethylene glycol monododecyl ether (Brij30). All-atom molecular dynamics simulation was performed, and the free energies of binding the solutes in the hydrophobic-core and headgroup regions of the micelles were computed using the energy-representation method. It was found in all the micelles examined that aromatic naphthalene is preferably located more outward than aliphatic propane and that the polar solutes are localized at the interface of the hydrophobic and hydrophilic regions. The roles of the surfactant and water were then elucidated by decomposing the free energy into the contributions from the respective species. Water was observed to play a decisive role in determining the binding location of the solute, while the surfactant was found to be more important for the overall stabilization of the solute within the micelle. The effects of attractive and repulsive interactions of the solute with the surfactant and water were further examined, and their competition was analyzed in connection with the preferable location of the solute in the micellar system. PMID:27117093

  12. Characterization of phenolic and other polar compounds in a lemon verbena extract by capillary electrophoresis-electrospray ionization-mass spectrometry.

    PubMed

    Quirantes-Piné, Rosa; Arráez-Román, David; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

    2010-09-01

    In this study, a CE-MS method has been developed to carry out the qualitative characterization of a lemon verbena (Lippia citriodora) extract for the first time. The CE and ESI-MS parameters were optimized with respect to resolution, analysis time and peak shape in order to maximize the number of compounds detected and the sensitivity of their determination. The use of two different MS analyzers, TOF-MS and IT-MS, enabled the tentative identification of the major components of this extract. Thus, using this method, 16 compounds were determined. Some of them have been previously identified by HPLC methods, although four compounds were also found for the first time in lemon verbena such as asperuloside, tuberonic acid glucoside or 5'-hydroxyjasmonic acid 5'-O-glucoside, shanzhiside and ixoside. These results demonstrate that CE-MS generates data complementary to those obtainable by HPLC-MS and it is particularly suited to the analysis of plant metabolites. PMID:20715141

  13. Synthesis of newer 1,2,3-triazole linked chalcone and flavone hybrid compounds and evaluation of their antimicrobial and cytotoxic activities.

    PubMed

    Kant, Rama; Kumar, Dharmendra; Agarwal, Drishti; Gupta, Rinkoo Devi; Tilak, Ragini; Awasthi, Satish Kumar; Agarwal, Alka

    2016-05-01

    The present study was carried out in an attempt to synthesize a new class of antimicrobial and antiplasmodial agents by copper catalyzed click chemistry to afford 25 compounds 10-14(a-e) of 1,4-disubstituted-1,2,3-triazole derivatives of chalcones and flavones. The structures of the newly synthesized compounds were established by elemental analysis, IR, (1)H NMR, (13)C NMR and Mass spectral data. The newly synthesized compounds were evaluated for their antibacterial activity against Gram positive bacteria (Staphylococcus aureus, Enterococcus faecalis), Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Shigella boydii, Klebsiella pneumoniae) and antifungal activity against (Candida albicans, Candida tropicalis, Candida parapsilosis, Cryptococcus neoformans, Dermatophyte) as well as molds (Aspergillus niger, Aspergillus fumigatus). The antiplasmodial and cytotoxic activities of these compounds were also evaluated against human malaria parasite Plasmodium falciparum strain 3D7 and human hepato-cellular carcinoma cells (Huh-7), respectively. Compounds 10a, 10c, 10d, 12c and 14e showed promising antibacterial activity while compounds 10e, 11d, 11e, 12c, 13a, 13b, 13e, 14a and 14d showed good antifungal activity as compared to the corresponding standard drugs. Compound 10b was found to be the most active against Plasmodium falciparum while the remaining compounds showed moderate to weak antiplasmodial activity. However, cytotoxic activities of all compounds were found ineffective against Huh-7 cells. PMID:26922227

  14. The development of high-performance alkali-hybrid polarized He3 targets for electron scattering

    SciTech Connect

    Singh, Jaideep T.; Dolph, Peter A.M.; Tobias, William Al; Averett, Todd D.; Kelleher, Aiden; Mooney, K. E.; Nelyubin, Vladimir V.; Wang, Yunxiao; Zheng, Yuan; Cates, Gordon D.

    2015-05-01

    We present the development of high-performance polarized ³He targets for use in electron scattering experiments that utilize the technique of alkali-hybrid spin-exchange optical pumping. We include data obtained during the characterization of 24 separate target cells, each of which was constructed while preparing for one of four experiments at Jefferson Laboratory in Newport News, Virginia. The results presented here document dramatic improvement in the performance of polarized ³He targets, as well as the target properties and operating parameters that made those improvements possible. Included in our measurements were determinations of the so-called X-factors that quantify a temperature-dependent and as-yet poorly understood spin-relaxation mechanism that limits the maximum achievable ³He polarization to well under 100%. The presence of this spin-relaxation mechanism was clearly evident in our data. We also present results from a simulation of the alkali-hydrid spin-exchange optical pumping process that was developed to provide guidance in the design of these targets. Good agreement with actual performance was obtained by including details such as off-resonant optical pumping. Now benchmarked against experimental data, the simulation is useful for the design of future targets. Included in our results is a measurement of the K- ³He spin-exchange rate coefficient $k^\\mathrm{K}_\\mathrm{se} = \\left ( 7.46 \\pm 0.62 \\right )\\!\\times\\!10^{-20}\\ \\mathrm{cm^3/s}$ over the temperature range 503 K to 563 K.

  15. Synthesis, crystal structure and luminescent properties of one new inorganic-organic hybrid compound [O 2NBzQL] 4[Cd(SCN) 4(NCS) 2] (O 2NBzQL = 1-(4'-NO 2-benzyl)quinolinium cation)

    NASA Astrophysics Data System (ADS)

    Bai, Yan; Hu, Xue-Fu; Dang, Dong-Bin; Bi, Feng-Lei; Niu, Jing-Yang

    2011-01-01

    A new inorganic-organic hybrid compound [O 2NBzQL] 4[Cd(SCN) 4(NCS) 2] (O 2NBzQL = 1-(4'-NO 2-benzyl)quinolinium cation) has been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Cd(II) atom has an distorted octahedral environment with an N 4S 2 donor set. In solid state there are three types of face-to-face π-π interactions between adjacent cations and multiform C-H⋯S and C-H⋯N hydrogen bonds between [O 2NBzQL] + cations and cadmium thiocyanate anions. The luminescent properties of the title compound were both investigated in H 2O solution and in solid state at room temperature, respectively.

  16. Synthesis, crystal structure and luminescent properties of one new inorganic-organic hybrid compound [O2NBzQL]4[Cd(SCN)4(NCS)2] (O2NBzQL=1-(4'-NO2-benzyl)quinolinium cation).

    PubMed

    Bai, Yan; Hu, Xue-Fu; Dang, Dong-Bin; Bi, Feng-Lei; Niu, Jing-Yang

    2011-01-01

    A new inorganic-organic hybrid compound [O2NBzQL]4[Cd(SCN)4(NCS)2] (O2NBzQL=1-(4'-NO2-benzyl)quinolinium cation) has been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Cd(II) atom has an distorted octahedral environment with an N4S2 donor set. In solid state there are three types of face-to-face π-π interactions between adjacent cations and multiform C-H⋯S and C-H⋯N hydrogen bonds between [O2NBzQL]+ cations and cadmium thiocyanate anions. The luminescent properties of the title compound were both investigated in H2O solution and in solid state at room temperature, respectively. PMID:20934904

  17. Adsorption behaviors of neutral and ionizable compounds on hybrid stationary phases in the absence (BEH-C18) and the presence (CSH-C18) of immobile surface charges.

    PubMed

    Gritti, Fabrice; Guiochon, Georges

    2013-03-22

    The adsorption behaviors of a neutral (caffeine) and a positively charged compound (nortriptylinium) are investigated on two RPLC/hybrid stationary phases, eluted with a low ionic strength buffer (phosphate buffer, W(S)pH 2.63, I=10mM). The first phase, bridge ethylene hybrid (BEH), is neutral at all pHs whereas the second, charged surface hybrid (CSH), contains a protonated ligand at W(W)pH <7. The band profiles of these two compounds eluted by mixture of acetonitrile and water were recorded under overloaded conditions. The adsorption isotherms of the neutral compound on both columns were well accounted for by a heterogeneous Linear-Langmuir (LL) model, which has an adsorption-desorption equilibrium constants about twice larger for caffeine on the CSH than on the BEH, due to charge-dipole interactions. In contrast, at low loadings (0.3 and 1.2μL, C=30g/L), the adsorption isotherm of the charged compound can be accounted for by a homogeneous electrostatically modified Langmuir (EML) or by a heterogeneous bi-EML implicit isotherms onto the CSH and BEH adsorbent, respectively. Electrostatic repulsions definitely account the lesser retention of the ionizable compound on CSH than on BEH. This is explained by the surface potential of CSH-C18 at 20mV and by the subsequent decrease of the equilibrium constant of weak adsorption sites (C18 environment) and removal of the strong adsorption sites (accessible silanols). At the highest sample loadings (5 and 20μL, C=30g/L), the EML and the bi-EML isotherms failed because some adsorbate-adsorbate interactions take place when bulk concentrations exceed 0.2g/L. The experimental data were then successively fitted to an empirical heterogeneous Langmuir-Moreau (LM) explicit isotherm. The best saturation capacities of the empirical heterogeneous LM isotherm is consistent with the manufacturer's estimate of the surface concentration of residual silanols onto the BEH- and CSH-C18 endcapped adsorbent (<0.1μmol/m(2)). PMID:23422897

  18. Porous polymer monoliths: Preparation of sorbent materials with high-surface areas and controlled surface chemistry for high-throughput, online, solid-phase extraction of polar organic compounds

    SciTech Connect

    Xie, S.; Svec, F.; Frechet, J.M.J.

    1998-12-01

    Porous monolithic materials with high surface areas have been prepared from commercial 80% divinylbenzene. The pore properties of these materials are controlled by the type and composition of the porogenic solvent and by the percentage of cross-linking monomer (divinylbenzene) in the polymerization mixture. Surface area was found to increase with the divinylbenzene content of the monolith. Using high-grade divinylbenzene and a suitable porogenic solvent, monolithic materials with specific surface areas as high as 400 m{sup 2}/g yet still permeable to liquids at reasonable back pressure were obtained for the first time. A macroporous material with hydrodynamic properties optimized for solid-phase extraction has been designed and its permeability and adsorption ability was demonstrated by adsorbing phenols at flow velocities that exceed those of current materials by a factor of 30. A unique set of polymerization conditions had to be developed to allow the incorporation of polar 2-hydroxylethyl methacrylate into the hydrophobic nonpolar backbone of the divinylbenzene monolithic material. This improves wettability while high-flow properties are maintained and unusually high recoveries of polar compounds are allowed.

  19. The motley family of polar compounds (MV)[M(X{sub 5-x}X Prime {sub x})] based on anionic chains of trans-connected M{sup (III)}(X,X Prime ){sub 6} octahedra (M=Bi, Sb; X, X Prime =Cl, Br, I) and methylviologen (MV) dications

    SciTech Connect

    Leblanc, Nicolas; Mercier, Nicolas; Allain, Magali; Toma, Oksana; Auban-Senzier, Pascale; Pasquier, Claude

    2012-11-15

    The search for hybrid organic-inorganic materials remains a great challenge in the field of ferroelectrics. Following the discovery of the room temperature ferroelectric material (MV)[BiI{sub 3}Cl{sub 2}] (MV{sup 2+}: methylviologen) exhibiting the highest polarization value in the field of hybrid ferroelectrics, we report here nine new hybrids with the general formulation (MV)[M{sup (III)}X{sub 5-x}X Prime {sub x}] (M=Bi, Sb; X, X Prime =Cl, Br, I): (MV)[BiCl{sub 3.3}Br{sub 1.7}] (1), (MV)[BiCl{sub 1.3}Br{sub 3.7}] (2), (MV)[BiBr{sub 3.2}I{sub 1.8}] (3), (MV)[SbCl{sub 5}] (4), (MV)[SbBr{sub 5}] (5), (MV)[SbCl{sub 3.8}Br{sub 1.2}] (6), (MV)[SbCl{sub 2.4}Br{sub 2.6}] (7), (MV)[SbI{sub 3}Cl{sub 2}] (8) and (MV)[SbBr{sub 3.8}I{sub 1.2}] (9). Depending on the presence of polar chains or not, and on the coupling of polar chains, two types of centrosymmetrical structures [C1] and [C2] and two types of polar structures [P1] and [P2] are defined. (2) undergoes a paraelectric-to-relaxor ferroelectric transition around 100-150 K depending of the frequency showing that the Curie temperature, T{sub C}, of (MV)[BiBr{sub 5}] (243 K) can be modulated by the substitution of Br by Cl. The most interesting family is the [P2] type because the syn coupling of polar chains is in favor of high polarization values, as in (MV)[BiI{sub 3}Cl{sub 2}]. Five of the nine new hybrids, (4), (6-9), which have the [P2] type structure are potential ferroelectrics. - Graphical abstract: The methylviologen haloantimonate (MV)[SbX{sub 5-x}X Prime {sub x}] families (X, X Prime =Cl, Br, I) - [P1] and [P2] are the two kinds of polar structures - and view of the (MV)[SbBr{sub 3.8}I{sub 1.2}] hybrid based on chiral polar chains which are in syn coupling. Highlights: Black-Right-Pointing-Pointer Nine hybrids based on methylviologen and halometalate chains have been discovered. Black-Right-Pointing-Pointer The polar nature of chains is due to the ns{sup 2} stereoactivity of Sb{sup (III)} or Bi{sup (III

  20. Hydrogen bonded supra-molecular framework in inorganic-organic hybrid compounds of Mn(II) and Zn(II): Syntheses, structures, and photoluminescent studies

    NASA Astrophysics Data System (ADS)

    Yan, Li; Li, Chuanbi; Chen, Xiaoli

    2014-01-01

    In our efforts to tune the structures of compounds by selection of polycarboxylic acid ligands and N-heterocyclic ligands, two novel unreported compounds [Mn(cipt)(m-BDC)·H2O]n (1) and [Zn(mip)(NDC)]n (2) were obtained by hydrothermal reaction, where cipt = 2-(3-chlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, m-BDC = isophthalic acid, mip = 2-(3-methoxyphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, and NDC = naphthalene-1,4-dicarboxylic acid. All compounds have been characterized by IR, elemental analyses, single crystal X-ray diffraction, and thermogravimetric analysis (TGA). Structural analyses show that compounds 1 and 2 possess mononuclear structures and exhibit 1D zigzag chain structure. The intermolecular O-H⋯O and N-H⋯O interactions extend the compounds into 2D sheet networks. There are H-bonds and π-π interactions in the title compounds. Furthermore, the solid-state fluorescence spectrum of compounds 1 and 2 were also investigated.

  1. Deep Co penetration and spin-polarization of C{sub 60} molecules at hybridized Co-C{sub 60} interfaces

    SciTech Connect

    Cheng, Pei-Yu; Chan, Yuet-Loy; Hsu, Yao-Jane; Chiang, Meng-Ruei; Wang, Pen-Cheng; Wei, D. H.

    2014-01-27

    We used near-edge x-ray absorption fine structure spectroscopy to identify the interplays at organic semiconductor-ferromagnet interfaces. When monitoring the L-edge intensity of 0.36 nm Co depositing on C{sub 60} films of various thicknesses, we detected weaker Co signal from structures with larger C{sub 60} thicknesses. Having determined that the electron mean escape depth in C{sub 60} is 4.9 nm, further model analysis indicates that the decline of spectral intensity is due to deep penetration of Co clusters. Finally, C K-edge spectra reveal clear evidences of orbital hybridization between Co and C{sub 60} as well as a visible dichroic effect at 125 K.

  2. Characterization of polyphenols, sugars, and other polar compounds in persimmon juices produced under different technologies and their assessment in terms of compositional variations.

    PubMed

    Jiménez-Sánchez, Cecilia; Lozano-Sánchez, Jesús; Marti, Nuria; Saura, Domingo; Valero, Manuel; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

    2015-09-01

    Persimmon juice is emerging in the global juice market as a new wholesome commercial juice that could effectively complement a healthy diet, given the epidemiological evidence linking a diet rich in fruits and vegetables with reduced incidences of chronic diseases. However, little data are available on the persimmon-juice composition or on the effect of the technological treatment employed for its production. The present work performs a complete qualitative analytical characterization through high-performance liquid chromatography coupled to electrospray time-of-flight mass spectrometry (HPLC-DAD-ESI-TOF/MS) of the diverse persimmon juices produced under different technologies in a pilot plant (clarification, astringency removal, flash vacuum expansion, centrifugation and pasteurization) in order to evaluate the effect of the different production procedures on the polar chemical profile of persimmon juice. Persimmon-juice extracts have been found to be a source of sugars, protein derivatives, organic acids, vitamins, and polyphenols, including simple polyphenols (phenolic acids and flavonoids) and polymerized flavan-3-ols. A marked influence of processing on the composition of the juices has been noticed. Extracts 3 and 7 (undergoing the combinations of clarification and centrifugation, and astringency removal, centrifugation and pasteurization, respectively) contained more polyphenols, which may help reduce risk of chronic diseases. PMID:25842339

  3. Fluorescence polarization-based assays for detecting compounds binding to inactive c-Jun N-terminal kinase 3 and p38α mitogen-activated protein kinase.

    PubMed

    Ansideri, Francesco; Lange, Andreas; El-Gokha, Ahmed; Boeckler, Frank M; Koch, Pierre

    2016-06-15

    Two fluorescein-labeled pyridinylimidazoles were synthesized and evaluated as probes for the binding affinity determination of potential kinase inhibitors to the c-Jun N-terminal kinase 3 (JNK3) and p38α mitogen-activated protein kinase (MAPK). Fluorescence polarization (FP)-based competition binding assays were developed for both enzymes using 1-(3',6'-dihydroxy-3-oxo-3H-spiro[isobenzofuran-1,9'-xanthen]-5-yl)-3-(4-((4-(4-(4-fluorophenyl)-2-(methylthio)-1H-imidazol-5-yl)pyridin-2-yl)amino)phenyl)thiourea (5) as an FP probe (JNK3: Kd = 3.0 nM; p38α MAPK: Kd = 5.7 nM). The validation of the assays with known inhibitors of JNK3 and p38α MAPK revealed that both FP assays correlate very well with inhibition data received by the activity assays. This, in addition to the viability of both FP-based binding assays for the high-throughput screening procedure, makes the assays suitable as inexpensive prescreening protocols for JNK3 and p38α MAPK inhibitors. PMID:26954235

  4. SrZn{sub 2}Sn{sub 2} and Ca{sub 2}Zn{sub 3}Sn{sub 6} - two new Ae-Zn-Sn polar intermetallic compounds (Ae: alkaline earth metal)

    SciTech Connect

    Stegmaier, Saskia; Faessler, Thomas F.

    2012-08-15

    SrZn{sub 2}Sn{sub 2} and Ca{sub 2}Zn{sub 3}Sn{sub 6}, two closely related new polar intermetallic compounds, were obtained by high temperature reactions of the elements. Their crystal structures were determined with single crystal XRD methods, and their electronic structures were analyzed by means of DFT calculations. The Zn-Sn structure part of SrZn{sub 2}Sn{sub 2} comprises (anti-)PbO-like {l_brace}ZnSn{sub 4/4}{r_brace} and {l_brace}SnZn{sub 4/4}{r_brace} layers. Ca{sub 2}Zn{sub 3}Sn{sub 6} shows similar {l_brace}ZnSn{sub 4/4}{r_brace} layers and {l_brace}Sn{sub 4}Zn{r_brace} slabs constructed of a covalently bonded Sn scaffold capped by Zn atoms. For both phases, the two types of layers are alternatingly stacked and interconnected via Zn-Sn bonds. SrZn{sub 2}Sn{sub 2} adopts the SrPd{sub 2}Bi{sub 2} structure type, and Ca{sub 2}Zn{sub 3}Sn{sub 6} is isotypic to the R{sub 2}Zn{sub 3}Ge{sub 6} compounds (R=La, Ce, Pr, Nd). Band structure calculations indicate that both SrZn{sub 2}Sn{sub 2} and Ca{sub 2}Zn{sub 3}Sn{sub 6} are metallic. Analyses of the chemical bonding with the electron localization function (ELF) show lone pair like basins at Sn atoms and Zn-Sn bonding interactions between the layers for both title phases, and covalent Sn-Sn bonding within the {l_brace}Sn{sub 4}Zn{r_brace} layers of Ca{sub 2}Zn{sub 3}Sn{sub 6}. - Graphical abstract: Crystal structures of the new Ae-Zn-Sn polar intermetallic phases SrZn{sub 2}Sn{sub 2} and Ca{sub 2}Zn{sub 3}Sn{sub 6}. Highlights: Black-Right-Pointing-Pointer New polar intermetallic phases SrZn{sub 2}Sn{sub 2} and Ca{sub 2}Zn{sub 3}Sn{sub 6}. Black-Right-Pointing-Pointer Obtained by high temperature reactions of the elements. Black-Right-Pointing-Pointer Single crystal XRD structure determination and DFT electronic structure calculations. Black-Right-Pointing-Pointer Closely related crystal and electronic structures. Black-Right-Pointing-Pointer Metallic conductivity coexisting with lone pairs and covalent bonding

  5. Synthesis, crystal structure, thermal analysis and vibrational spectroscopy accomplished with DFT calculation of new hybrid compound [2-CH3C6H4NH3]HSO4.H2O

    NASA Astrophysics Data System (ADS)

    Ben Hassen, C.; Boujelbene, M.; Marweni, S.; Bahri, M.; Mhiri, T.

    2015-10-01

    The present paper undertakes the study of a new organic/inorganic hybrid compound [2-CH3C6H4NH3]HSO4.H2O characterized by the X-ray diffraction, TG-DTA, IR and Raman spectroscopy accomplished with DFT calculation. It is crystallized in the monoclinic system with the centrosymmetric space group P 21/c, with a = 9.445 (5) Å, b = 10.499 Å, c = 10.073 Å, β = 90.627 (5)° and Z = 4. The atomic arrangement can be described as inorganic layers built by infinite chains, parallel to the (a c) planes between which the organic cations are inserted. In this atomic arrangement, hydrogen bonds and π-π interactions between the different species have an important role in the tri-dimensional network cohesion. Besides, the X-ray powder diffraction of the title compound confirms the existence of only one phase at room temperature. The thermal decomposition of precursors studied by thermo gravimetric analysis (TGA), the differential thermal analysis (DTA) and the temperature-dependent X-ray diffraction, show crystalline anhydrous compounds upon dehydration. DFT/BHHLYP calculations were performed, using the DZV (d,p) basis set, to determine the harmonic frequencies of the vibrational modes of an optimized cluster structure. The calculated modes were animated using the Molden graphical package to give tentative assignments of the observed IR and Raman spectra.

  6. Synthesis, crystal structure and non-linear optical properties of inorganic-organic hybrid compound based on face-sharing octahedral [PbBr3]∞ chains

    NASA Astrophysics Data System (ADS)

    Ben Ahmed, A.; Feki, H.; Abid, Y.

    2015-09-01

    4-BenzylPiPeridine-PbBr3 has been synthesized. The crystal structures of the title compound have been defined by X-ray diffraction analysis and characterized by FT-IR, Raman and UV-visible instrumental methods. The recorded spectrum by UV-visible spectroscopy for the investigated compound show good transparency in the visible region. This result indicates a non-zero value of the first Hyperpolarizability. We also report DFT calculations of the electric dipole moments (μ), Polarizability (α), the first Hyperpolarizability (β) and HOMO-LUMO analysis of the title compound was theoretically investigated by Gaussian 03 package. Our results suggest that the investigated material might have microscopic nonlinear optical behavior with non-zero values.

  7. Synthesis, structure, and bonding in K12Au21Sn4. A polar intermetallic compound with dense Au20 and open AuSn4 layers

    SciTech Connect

    Li, Bin; Kim, Sung-Jin; Miller, Gordon J.; and Corbett, John D.

    2009-10-29

    The new phase K{sub 12}Au{sub 21}Sn{sub 4} has been synthesized by direct reaction of the elements at elevated temperatures. Single crystal X-ray diffraction established its orthorhombic structure, space group Pmmn (No. 59), a = 12.162(2); b = 18.058(4); c = 8.657(2) {angstrom}, V = 1901.3(7) {angstrom}{sup 3}, and Z = 2. The structure consists of infinite puckered sheets of vertex-sharing gold tetrahedra (Au{sub 20}) that are tied together by thin layers of alternating four-bonded-Sn and -Au atoms (AuSn{sub 4}). Remarkably, the dense but electron-poorer blocks of Au tetrahedra coexist with more open and saturated Au-Sn layers, which are fragments of a zinc blende type structure that maximize tetrahedral heteroatomic bonding outside of the network of gold tetrahedra. LMTO band structure calculations reveal metallic properties and a pseudogap at 256 valence electrons per formula unit, only three electrons fewer than in the title compound and at a point at which strong Au-Sn bonding is optimized. Additionally, the tight coordination of the Au framework atoms by K plays an important bonding role: each Au tetrahedra has 10 K neighbors and each K atom has 8-12 Au contacts. The appreciably different role of the p element Sn in this structure from that in the triel members in K{sub 3}Au{sub 5}In and Rb{sub 2}Au{sub 3}Tl appears to arise from its higher electron count which leads to better p-bonding (valence electron concentrations = 1.32 versus 1.22).

  8. Polarization Filtering of SAR Data

    NASA Technical Reports Server (NTRS)

    Dubois, Pascale C.; Van Zyl, Jakob J.

    1991-01-01

    Theoretical analysis of polarization filtering of synthetic-aperture-radar (SAR) returns provide hybrid method applied to either (1) maximize signal-to-noise ratio of return from given target or (2) enhance contrast between targets of two different types (that have different polarization properties). Method valid for both point and extended targets and for both monostatic and bistatic radars as well as SAR. Polarization information in return signals provides more complete description of radar-scattering properties of targets and used to obtain additional information about targets for use in classifying them, discriminating between them, or enhancing features of radar images.

  9. Syntheses, structures and photocatalytic properties of five new praseodymium-antimony oxochlorides: from discrete clusters to 3D inorganic-organic hybrid racemic compounds.

    PubMed

    Zou, Guo-Dong; Wang, Ze-Ping; Song, Ying; Hu, Bing; Huang, Xiao-Ying

    2014-07-14

    Five novel praseodymium-antimony oxochloride (Pr-Sb-O-Cl) cluster-based compounds, namely (2-MepyH)2[Fe(1,10-phen)3]2[Pr4Sb12O18Cl14.6(OH)2.4(Hsal)]·H2O (1), (2-MepyH)2[Fe(1,10-phen)3]4{[Pr4Sb12O18Cl13.5(OH)0.5](bcpb)2[Pr4Sb12O18Cl13.5(OH)0.5]}·42H2O (2), (3-MepyH)2[Fe(1,10-phen)3]{[Pr4Sb12O18Cl13(H2O)2](bcpb)}·2(3-Mepy)·3H2O (3), [Fe(1,10-phen)3]2{[Pr4Sb12O18Cl10(H2O)2](bcpb)2}·3(3-Mepy)·13H2O (4), and (2-MepyH)6[Fe(1,10-phen)3]10{[Pr4Sb12O18Cl13(OH)2]2[Pr4Sb12O18Cl9][Pr4Sb12O18Cl9(OH)2]2(Hpdc)10(pdc)2}·110H2O (5) (2-Mepy = 2-methylpyridine, 3-Mepy = 3-methylpyridine, 1,10-phen = 1,10-phenanthroline, H2sal = salicylic acid, H3bcpb = 3,5-bis(4-carboxyphenoxy)benzoic acid, H3pdc = 3,5-pyrazoledicarboxylic acid) have been solvothermally synthesized and structurally characterized. Compound 1 is the first zero-dimensional (0D) Pr-Sb-O-Cl cluster decorated by an organic ligand. Compounds 2-4 are constructed from the same H3bcpb ligands but adopt different structures: 2 represents a rare example of a one-dimensional (1D) nanotubular structure based on high-nuclearity clusters; 3 exhibits a two-dimensional (2D) mono-layered structure, in which left-handed and right-handed helical chains are alternately arranged, while 4 features a double-layered structure with an unprecedented (3,3,6)-connected 3-nodal topological net. Compound 5 is a unique three-dimensional (3D) 2-fold interpenetrating racemic compound, simultaneously containing three kinds of Pr-Sb-O-Cl-pdc clusters. UV-light photocatalytic H2 evolution activity was observed for compound 3 with Pt as a co-catalyst and MeOH as a sacrificial electron donor. In addition, the magnetic properties of compounds 1 and 5 are also studied. PMID:24869770

  10. Design, synthesis, and anticonvulsant activity of new hybrid compounds derived from 2-(2,5-dioxopyrrolidin-1-yl)propanamides and 2-(2,5-dioxopyrrolidin-1-yl)butanamides.

    PubMed

    Kamiński, Krzysztof; Zagaja, Mirosław; Łuszczki, Jarogniew J; Rapacz, Anna; Andres-Mach, Marta; Latacz, Gniewomir; Kieć-Kononowicz, Katarzyna

    2015-07-01

    The library of 27 new 1-(4-phenylpiperazin-1-yl)- or 1-(morpholin-4-yl)-(2,5-dioxopyrrolidin-1-yl)propanamides and (2,5-dioxopyrrolidin-1-yl)butanamides as potential new hybrid anticonvulsant agents was synthesized. These hybrid molecules join the chemical fragments of well-known antiepileptic drugs (AEDs) such as ethosuximide, levetiracetam, and lacosamide. Compounds 5, 10, 11, and 24 displayed the broad spectra of activity across the preclinical seizure models, namely, the maximal electroshock (MES) test, the subcutaneous pentylenetetrazole (scPTZ) test, and the six-hertz (6 Hz) model of pharmacoresistant limbic seizures. The highest protection was demonstrated by 11 (ED50 MES = 88.4 mg/kg, ED50 scPTZ = 59.9 mg/kg, ED50 6 Hz = 21.0 mg/kg). This molecule did not impair the motor coordination of animals in the chimney test even at high doses (TD50 > 1500 mg/kg), yielding superb protective indexes (PI MES > 16.97, PI PTZ > 25.04, PI 6 Hz > 71.43). As a result, 11 displayed distinctly better safety profile than clinically relevant AEDs ethosuximide, lacosamide, or valproic acid. PMID:26052884

  11. Synthesis and structure-activity relationships of novel hybrid ferrocenyl compounds based on a bicyclic core skeleton for breast cancer therapy.

    PubMed

    Li, Changhao; Tang, Chu; Hu, Zhiye; Zhao, Chenxi; Li, Chenlu; Zhang, Silong; Dong, Chune; Zhou, Hai-Bing; Huang, Jian

    2016-07-01

    Breast cancer is the most frequent cancer in women worldwide, and incidence is increasing year by year. Although current selective estrogen receptor modulators (SERMs) have clear advantages in the treatment of hormone-responsive breast cancer, they are ineffective for ER(-). In this study, we describe the design and synthesis of a series of dual-acting estrogen receptor (ER) and histone deacetylase (HDAC) inhibitors with incorporation of the ferrocenyl moiety, leading to novel hybrid ferrocenyl complexes (FcOBHS-HDACis) for breast cancer therapy. It is worth to note that these ferrocenyl conjugates could not only potently inhibit HDACs and the proliferation of ERα positive (ER(+)) breast cancer cells (MCF-7), but also show significant antiproliferative effect on ER(-) breast cancer cells (MDA-MB-231). Thus, the FcOBHS-HDACi conjugates represent a novel approach to the development of efficiently dual-acting agents for treatment of breast cancer. PMID:27240467

  12. Polarization developments

    SciTech Connect

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist.

  13. Accurate treatment of spontaneous polarization in III-nitrides

    NASA Astrophysics Data System (ADS)

    Dreyer, Cyrus E.; Janotti, Anderson; van de Walle, Chris G.

    2015-03-01

    The III-nitride compounds assume the wurtzite crystal structure in the ground state and therefore exhibit spontaneous and piezoelectric dipole moments in the c direction. Discontinuities in these moments at heterostructure interfaces result in electric fields in the layers, which can be detrimental because they separate electrons and holes in quantum wells. Accurate values for polarization differences are critical for understanding and engineering III-nitride heterostructures. Direct experimental measurement of spontaneous polarization has not been possible to date, and calculations are complicated by the necessity to choose a reference structure. The universal choice of reference structure for wurtzite has been zincblende; we demonstrate that this choice does not allow consistent determination of the differences of spontaneous polarizations between materials, which determine their physical manifestation. Using first-principles techniques based on hybrid density functional theory, we have determined polarization discontinuities using a consistent reference based on the hexagonal layered structure of these materials. We will discuss the results in light of available experimental data, and outline consequences for device simulations. Work supported by DOE.

  14. Neuronal polarization.

    PubMed

    Takano, Tetsuya; Xu, Chundi; Funahashi, Yasuhiro; Namba, Takashi; Kaibuchi, Kozo

    2015-06-15

    Neurons are highly polarized cells with structurally and functionally distinct processes called axons and dendrites. This polarization underlies the directional flow of information in the central nervous system, so the establishment and maintenance of neuronal polarization is crucial for correct development and function. Great progress in our understanding of how neurons establish their polarity has been made through the use of cultured hippocampal neurons, while recent technological advances have enabled in vivo analysis of axon specification and elongation. This short review and accompanying poster highlight recent advances in this fascinating field, with an emphasis on the signaling mechanisms underlying axon and dendrite specification in vitro and in vivo. PMID:26081570

  15. Polarization Aberrations

    NASA Technical Reports Server (NTRS)

    Mcguire, James P., Jr.; Chipman, Russell A.

    1990-01-01

    The analysis of the polarization characteristics displayed by optical systems can be divided into two categories: geometrical and physical. Geometrical analysis calculates the change in polarization of a wavefront between pupils in an optical instrument. Physical analysis propagates the polarized fields wherever the geometrical analysis is not valid, i.e., near the edges of stops, near images, in anisotropic media, etc. Polarization aberration theory provides a starting point for geometrical design and facilitates subsequent optimization. The polarization aberrations described arise from differences in the transmitted (or reflected) amplitudes and phases at interfaces. The polarization aberration matrix (PAM) is calculated for isotropic rotationally symmetric systems through fourth order and includes the interface phase, amplitude, linear diattenuation, and linear retardance aberrations. The exponential form of Jones matrices used are discussed. The PAM in Jones matrix is introduced. The exact calculation of polarization aberrations through polarization ray tracing is described. The report is divided into three sections: I. Rotationally Symmetric Optical Systems; II. Tilted and Decentered Optical Systems; and Polarization Analysis of LIDARs.

  16. Solvent-assisted stir bar sorptive extraction by using swollen polydimethylsiloxane for enhanced recovery of polar solutes in aqueous samples: Application to aroma compounds in beer and pesticides in wine.

    PubMed

    Ochiai, Nobuo; Sasamoto, Kikuo; David, Frank; Sandra, Pat

    2016-07-15

    A novel solvent-assisted stir bar sorptive extraction (SA-SBSE) technique was developed for enhanced recovery of polar solutes in aqueous samples. A conventional PDMS stir bar was swollen in several solvents with log Kow ranging from 1.0 to 3.5 while stirring for 30min prior to extraction. After extraction, thermal desorption - gas chromatography - (tandem) mass spectrometry (TD-GC-(MS/)MS) or liquid desorption - large volume injection (LD-LVI)-GC-MS were performed. An initial study involved investigation of potential solvents for SA-SBSE by weighing of the residual solvent in the swollen PDMS stir bar before and after extraction. Compared to conventional SBSE, SA-SBSE using diethyl ether, methyl isobutyl ketone, dichloromethane, diisopropyl ether and toluene provided higher recoveries from water samples for test solutes with log Kow<2.5. For SA-SBSE using dichloromethane, recoveries were improved by factors of 1.4-4.1, while maintaining or even improving the recoveries for test solutes with log Kow>2.5. The performance of the SA-SBSE method using dichloromethane, diisopropyl ether, and cyclohexane is illustrated with analyses of aroma compounds in beer and of pesticides in wine. PMID:27289502

  17. Syntheses and structures of two gold(I) coordination compounds derived from P-S hybrid ligands and their efficient catalytic performance in the photodegradation of nitroaromatics in water.

    PubMed

    Qi, Hai-Xiao; Wang, Jian-Feng; Ren, Zhi-Gang; Ning, Jin-Jiao; Lang, Jian-Ping

    2015-03-28

    Solvothermal reactions of HAuCl4·4H2O with a P-S hybrid ligand N,N-bis(diphenylphosphanylmethyl)-amino-thiocarbamide (dppatc) at 80 °C and 115 °C produced two Au-P-S complexes, [Au2(dppatc)2]Cl2 (1) and [Au2(dppmt)2]n (2) (dppmtH = (diphenylphosphino)methanethiol). 1 and 2 were characterized by elemental analyses, IR and UV-vis spectra, thermal-gravity analyses, powder X-ray diffraction and single crystal X-ray diffraction analyses. Compound 1 contains a dinuclear [Au2(dppatc)2](2+) dication, while 2 has a one-dimensional chain formed by AuAu aurophilic interactions. Compounds 1 and 2 exhibited excellent catalytic activity toward the photodegradation of nitrobenzene, p-nitrophenol and 2,4-dinitrophenol in aqueous solutions. The degradation reactions followed the zero-order kinetic model, in which the three nitroaromatics could be converted into CO2 and H2O in 92-96% yields. PMID:25708322

  18. Electronic structure of HgBa{sub 2}Ca{sub n-1}Cu{sub n}O{sub 2n+2} (n= 1, 2, 3) superconductor parent compounds from periodic hybrid density functional theory

    SciTech Connect

    Moreira, Iberio de P. R.; Rivero, Pablo; Illas, Francesc

    2011-02-21

    The electronic structure of HgBa{sub 2}Ca{sub n-1}Cu{sub n}O{sub 2n+2} (n= 1, 2, and 3) high T{sub c} superconductor parent compounds has been investigated by means of periodic hybrid density functional theory. Similar to other cuprates, these materials are predicted to exhibit an antiferromagnetic ground state with well localized S= 1/2 magnetic centers at the Cu{sup 2+} sites. However, the presence of the HgO{sub 2} structural units largely defines the nature of states dominating the energy range around Fermi energy. This results in a complex charge transfer character of the insulating gap which decreases when increasing the number of CuO{sub 2} planes in the unit cell, to the point that in the HgBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub 8} compound it becomes so small that one can claim that the resulting material is metallic. Nevertheless, the metallic character arises from the HgO{sub 2} structural units and coexists with the antiferromagnetic order arising from the localized spins at the Cu{sup 2+} sites.

  19. Preparation of a novel ionic hybrid stationary phase by non-covalent functionalization of single-walled carbon nanotubes with amino-derivatized silica gel for fast HPLC separation of aromatic compounds.

    PubMed

    Aral, Hayriye; Çelik, K Serdar; Aral, Tarık; Topal, Giray

    2016-03-01

    Single-walled carbon nanotubes (SWCNTs) were immobilized on spherical silica gel with a 4-μm average particle size and a 60-Å average pore size. The amino-derivatized silica gel was non-covalently coated with carboxylated SWCNTs to preserve the structure of the nanotubes and their physico-chemical properties. The novel ionic hybrid stationary phase was characterized by scanning electron microscopy (SEM), infra-red (IR) spectroscopy and elemental analysis, and then, it was used to fill an empty 150×4.6mm(2) high-performance liquid chromatography (HPLC) column. Chromatographic parameters, such as the theoretical plate number, retention factor and peak asymmetry factor, and analytical parameters, such as the limit of detection (LOD), limit of quantification (LOQ), linear range, calibration equation, and R(2) value, and quantitative analysis parameters were calculated for all of the analytes. Using different mobile phases, five different classes of aromatic hydrocarbons were separated in a very short analysis time of 4-8min. Furthermore, a high theoretical plate number (up to 25000) and an excellent peak asymmetry factor (1.0) were obtained. The results showed that the surface of the SWNTs had very strong interactions with aromatic groups, therefore providing high selectivity for the separation of different classes of aromatic compounds. This study indicates that SWCNTs enable the extension of the application range of the newly prepared stationary phases for the fast separation of aromatic compounds by HPLC. PMID:26717810

  20. Spring polar ozone behavior

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1992-01-01

    Understanding of the springtime behavior of polar stratospheric ozone as of mid 1990 is summarized. Heterogeneous reactions on polar stratospheric clouds as hypothesis for ozone loss are considered and a simplified description of the behavior of Antarctic ozone in winter and spring is given. Evidence that the situation is more complicated than described by the theory is produced. Many unresolved scientific issues remain and some of the most important problems are identified. Ozone changes each spring since 1979 have clearly established for the first time that man made chlorine compounds influence stratospheric ozone. Long before important advances in satellite and in situ investigations, it was Dobson's decision to place a total ozone measuring spectrometer at Halley Bay in Antarctica during the International Geophysical Year and subsequent continuous monitoring which led to the discovery that ozone was being destroyed each spring by chlorine processed by polar stratospheric clouds.

  1. Polar Bear

    USGS Publications Warehouse

    Amstrup, S.D.; DeMaster

    1988-01-01

    Polar bears are long-lived, late-maturing carnivores that have relatively low rates of reproduction and natural mortality. Their populations are susceptible to disturbance from human activities, such as the exploration and development of mineral resources or hunting. Polar bear populations have been an important renewable resource available to coastal communities throughout the Arctic for thousands of years.

  2. Crystal structure, thermal studies, Hirshfeld surface analysis, vibrational and DFT investigation of organic-inorganic hybrid compound [C9H6NOBr2]2CuBr4·2H2O

    NASA Astrophysics Data System (ADS)

    Mesbeh, Radhia; Hamdi, Besma; Zouari, Ridha

    2016-12-01

    Single crystals of a hybrid organic/inorganic material with the formula [C9H6NOBr2]2CuBr4·2H2O were studied by X-ray diffraction. The compound crystallizes in the monoclinic system, space group C2/c with the following unit cell parameters: a = 7.8201 (12) Ǻ, b = 18.203 (3) Ǻ, c = 19.486 (3) Ǻ, β = 98.330 (5)°, Z = 4, V = 2744.6 (7) Ǻ3. Crystal structure was solved with a final R = 5.66% for 3483 independent reflections. The atomic arrangement shows an alternation of organic and inorganic layers. Between layers, the cohesion is performed via Osbnd H⋯Br, Csbnd H⋯Br, Nsbnd H⋯Br, Nsbnd H⋯O and Osbnd H⋯O hydrogen bending. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements have been carried out on [C9H6NOBr2]2CuBr4·2H2O crystal in the temperature range between 50 and 500 °C. The assignment of the observed bands in the solid state FTIR and Raman spectra of the compound was assisted by the theoretically predicted frequencies and compared with data previously reported for similar compounds. The theoretical geometrical parameters in the ground state have been investigated by density functional theory (DFT) with the B3LYP/LanL2DZ level of theory. The optical properties were investigated by optical absorption and show two bands at 279, 300 nm. The percentages of hydrogen bonding interactions are analyzed by Fingerprint plots of Hirshfeld surface.

  3. 8-fluoropurine compounds

    DOEpatents

    Barrio, Jorge R.; Satyamurthy, Nagichettiar; Namavari, Mohammad; Phelps, Michael E.

    2001-01-01

    An efficient, regiocontrolled approach to the synthesis of 8-fluoropurines by direct fluorination of purines with dilute elemental fluorine, or acetyl hypofluorite, is provided. In a preferred embodiment, a purine compound is dissolved in a polar solvent and reacted with a dilute mixture of F.sub.2 in He or other inert gas.

  4. Polarized rainbow.

    PubMed

    Können, G P; de Boer, J H

    1979-06-15

    The Airy theory of the rainbow is extended to polarized light. For both polarization directions a simple analytic expression is obtained for the intensity distribution as a function of the scattering angle in terms of the Airy function and its derivative. This approach is valid at least down to droplet diameters of 0.3 mm in visible light. The degree of polarization of the rainbow is less than expected from geometrical optics; it increases with droplet size. For a droplet diameter >1 mm the locations of the supernumerary rainbows are equal for both polarization directions, but for a diameter <1 mm the supernumerary rainbows of the weaker polarization component are located between those in the strong component. PMID:20212586

  5. Differential modulation of brain nicotinic acetylcholine receptor function by cytisine, varenicline, and two novel bispidine compounds: emergent properties of a hybrid molecule.

    PubMed

    Peng, Can; Stokes, Clare; Mineur, Yann S; Picciotto, Marina R; Tian, Chengju; Eibl, Christoph; Tomassoli, Isabelle; Guendisch, Daniela; Papke, Roger L

    2013-11-01

    Partial agonist therapies for the treatment of nicotine addiction and dependence depend on both agonistic and antagonistic effects of the ligands, and side effects associated with other nAChRs greatly limit the efficacy of nicotinic partial agonists. We evaluated the in vitro pharmacological properties of four partial agonists, two current smoking cessation drugs, varenicline and cytisine, and two novel bispidine compounds, BPC and BMSP, by using defined nAChR subtypes expressed in Xenopus laevis oocytes and human embryonic kidney 293 cells. Similar to varenicline and cytisine, BPC and BMSP are partial agonists of α4β2 nAChRs, although BMSP produced very little activation of these receptors. Unlike varenicline and cytisine, BPC and BMSP showed desired low activity. BPC produced mecamylamine-sensitive steady-state activation of α4* receptors that was not evident with BMSP. We evaluated the modulation of α4*- and α7-mediated responses in rat lateral geniculate nucleus (LGN) neurons and hippocampal stratum radiatum (SR) interneurons, respectively. The LGN neurons were sensitive to a very low concentration of varenicline, and the SR interneuron responses were also sensitive to varenicline at a submicromolar concentration. Although 300 nM BPC strongly inhibited the ACh-evoked responses of LGN neurons, it did not inhibit the α7 currents of SR interneurons. Similar results were observed with 300 nM BMSP. Additionally, the bispidine compounds were efficacious in the mouse tail suspension test, demonstrating that they affect receptors in the brain when delivered systemically. Our data indicate that BPC and BMSP are promising α4β2* partial agonists for pharmacotherapeutics. PMID:23959137

  6. Differential Modulation of Brain Nicotinic Acetylcholine Receptor Function by Cytisine, Varenicline, and Two Novel Bispidine Compounds: Emergent Properties of a Hybrid Molecule

    PubMed Central

    Peng, Can; Stokes, Clare; Mineur, Yann S.; Picciotto, Marina R.; Tian, Chengju; Eibl, Christoph; Tomassoli, Isabelle; Guendisch, Daniela

    2013-01-01

    Partial agonist therapies for the treatment of nicotine addiction and dependence depend on both agonistic and antagonistic effects of the ligands, and side effects associated with other nAChRs greatly limit the efficacy of nicotinic partial agonists. We evaluated the in vitro pharmacological properties of four partial agonists, two current smoking cessation drugs, varenicline and cytisine, and two novel bispidine compounds, BPC and BMSP, by using defined nAChR subtypes expressed in Xenopus laevis oocytes and human embryonic kidney 293 cells. Similar to varenicline and cytisine, BPC and BMSP are partial agonists of α4β2 nAChRs, although BMSP produced very little activation of these receptors. Unlike varenicline and cytisine, BPC and BMSP showed desired low activity. BPC produced mecamylamine-sensitive steady-state activation of α4* receptors that was not evident with BMSP. We evaluated the modulation of α4*- and α7-mediated responses in rat lateral geniculate nucleus (LGN) neurons and hippocampal stratum radiatum (SR) interneurons, respectively. The LGN neurons were sensitive to a very low concentration of varenicline, and the SR interneuron responses were also sensitive to varenicline at a submicromolar concentration. Although 300 nM BPC strongly inhibited the ACh-evoked responses of LGN neurons, it did not inhibit the α7 currents of SR interneurons. Similar results were observed with 300 nM BMSP. Additionally, the bispidine compounds were efficacious in the mouse tail suspension test, demonstrating that they affect receptors in the brain when delivered systemically. Our data indicate that BPC and BMSP are promising α4β2* partial agonists for pharmacotherapeutics. PMID:23959137

  7. Polar Glaciology

    NASA Technical Reports Server (NTRS)

    Robin, G. D.

    1984-01-01

    Two fields of research on polar ice sheets are likely to be of dominant interest during the 1990s. These are: the role of polar ice sheets in the hydrological cycle ocean-atmosphere-ice sheets-oceans, especially in relation to climate change; and the study and interpretation of material in deep ice cores to provide improved knowledge of past climates and of the varying levels of atmospheric constituents such as CO2, NOx, SO2, aerosols, etc., over the past 200,000 years. Both topics require a better knowledge of ice dynamics. Many of the studies that should be undertaken in polar regions by Earth Observing System require similar instruments and techniques to those used elsewhere over oceans and inland surfaces. However to study polar regions two special requirements need to be met: Earth Observing System satellite(s) need to be in a sufficiently high inclination orbit to cover most of the polar regions. Instruments must also be adapted, often by relatively limited changes, to give satisfactory data over polar ice. The observational requirements for polar ice sheets in the 1990s are summarized.

  8. Polar organic marker compounds in atmospheric aerosols during the LBA-SMOCC 2002 biomass burning experiment in Rondônia, Brazil: sources and source processes, time series, diel variations and size distributions

    NASA Astrophysics Data System (ADS)

    Claeys, M.; Kourtchev, I.; Pashynska, V.; Vas, G.; Vermeylen, R.; Wang, W.; Cafmeyer, J.; Chi, X.; Artaxo, P.; Andreae, M. O.; Maenhaut, W.

    2010-04-01

    Measurements of polar organic marker compounds were performed on aerosols that were collected at a pasture site in the Amazon basin (Rondônia, Brazil) using a High-Volume dichotomous sampler (HVDS) and a Micro-Orifice Uniform Deposit Impactor (MOUDI). The samplings were conducted within the framework of the LBA-SMOCC (Large-Scale Biosphere Atmosphere Experiment in Amazônia - Smoke Aerosols, Clouds, Rainfall, and Climate: Aerosols From Biomass Burning Perturb Global and Regional Climate) campaign, which took place from 9 September till 14 November 2002, spanning the late dry season (biomass burning), the transition period, and the onset of the wet season (clean conditions). In the present study a more detailed discussion is presented compared to previous reports on the behavior of selected polar marker compounds, including: (a) levoglucosan, a tracer for biomass burning, (b) malic acid, a tracer for the oxidation of semivolatile carboxylic acids, (c) tracers for secondary organic aerosol (SOA) from isoprene, i.e., the 2-methyltetrols (2-methylthreitol and 2-methylerythritol) and the C5-alkene triols [2-methyl-1,3,4-trihydroxy-1-butene (cis and trans) and 3-methyl-2,3,4-trihydroxy-1-butene], and (d) sugar alcohols (arabitol, mannitol, and erythritol), tracers for fungal spores. The results obtained for levoglucosan are covered first with the aim to address its contrasting behavior with that of malic acid, the isoprene SOA tracers, and the fungal spore tracers. The tracer data are discussed taking into account new insights that recently became available into their stability and/or aerosol formation processes. During all three periods, levoglucosan was the most dominant identified organic species in the PM2.5 size fraction of the HVDS samples. In the dry period levoglucosan reached concentrations of up to 7.5 μg m-3 and exhibited diel variations with a nighttime prevalence. It was closely associated with the PM mass in the size-segregated samples and was mainly

  9. Polar organic marker compounds in atmospheric aerosols during the LBA-SMOCC 2002 biomass burning experiment in Rondônia, Brazil: sources and source processes, time series, diel variations and size distributions

    NASA Astrophysics Data System (ADS)

    Claeys, M.; Kourtchev, I.; Pashynska, V.; Vas, G.; Vermeylen, R.; Wang, W.; Cafmeyer, J.; Chi, X.; Artaxo, P.; Andreae, M. O.; Maenhaut, W.

    2010-10-01

    Measurements of polar organic marker compounds were performed on aerosols that were collected at a pasture site in the Amazon basin (Rondônia, Brazil) using a high-volume dichotomous sampler (HVDS) and a Micro-Orifice Uniform Deposit Impactor (MOUDI) within the framework of the 2002 LBA-SMOCC (Large-Scale Biosphere Atmosphere Experiment in Amazônia - Smoke Aerosols, Clouds, Rainfall, and Climate: Aerosols From Biomass Burning Perturb Global and Regional Climate) campaign. The campaign spanned the late dry season (biomass burning), a transition period, and the onset of the wet season (clean conditions). In the present study a more detailed discussion is presented compared to previous reports on the behavior of selected polar marker compounds, including levoglucosan, malic acid, isoprene secondary organic aerosol (SOA) tracers and tracers for fungal spores. The tracer data are discussed taking into account new insights that recently became available into their stability and/or aerosol formation processes. During all three periods, levoglucosan was the most dominant identified organic species in the PM2.5 size fraction of the HVDS samples. In the dry period levoglucosan reached concentrations of up to 7.5 μg m-3 and exhibited diel variations with a nighttime prevalence. It was closely associated with the PM mass in the size-segregated samples and was mainly present in the fine mode, except during the wet period where it peaked in the coarse mode. Isoprene SOA tracers showed an average concentration of 250 ng m-3 during the dry period versus 157 ng m-3 during the transition period and 52 ng m-3 during the wet period. Malic acid and the 2-methyltetrols exhibited a different size distribution pattern, which is consistent with different aerosol formation processes (i.e., gas-to-particle partitioning in the case of malic acid and heterogeneous formation from gas-phase precursors in the case of the 2-methyltetrols). The 2-methyltetrols were mainly associated with the

  10. Polarization Transfer by Solution in Laser-Polarized Liquid Xenon

    NASA Astrophysics Data System (ADS)

    Fitzgerald, R. J.; Sauer, K. L.; Happer, W.

    1998-05-01

    We have dissolved compounds in hyperpolarized liquid Xe, in which the ^129Xe polarization was ~ 20%, and have observed the transfer of polarization through cross-relaxation from ^129Xe to other spins in solution. We have measured enhanced NMR signals for ^1H that are more than a factor of 45 larger than thermal polarization signals at 200 K and 1.4 T. For ^13C, we have seen signal enhancements of over 70. The lifetimes of the enhancements were ~ 20 min. In dissolved toluene, we have further observed different enhancements of the ring and the methyl proton signals.

  11. Quantitative target and systematic non-target analysis of polar organic micro-pollutants along the river Rhine using high-resolution mass-spectrometry--Identification of unknown sources and compounds.

    PubMed

    Ruff, Matthias; Mueller, Miriam S; Loos, Martin; Singer, Heinz P

    2015-12-15

    In this study, the contamination by polar organic pollutants was investigated along the Rhine River, an important source of drinking water for 22 million people in central Europe. Following the flow of the river, a traveling water mass was sampled using weekly flow-proportional composite samples at ten different downstream sites, including main tributaries. Using a broad analytical method based on solid phase extraction and high-resolution mass spectrometry, the water was analyzed for more than 300 target substances. While the water in Lake Constance contained only 83 substances in often low concentrations, the number of detects found in the water phase increased to 143 substances and a weekly load of more than 7 tons at the last sampling site, the Dutch-German border. Mostly present were chemicals originating from wastewater treatment plants, especially the artificial sweetener Acesulfam and two pharmaceuticals, Metformin and Gabapentin, which dominate the weekly load up to 58%. Although the sample campaign was performed in a dry period in early spring, a large variety of pesticides and biocides were detected. Several industrial point sources were identified along the waterway's 900 km journey, resulting in high concentrations in the tributaries and loads of up to 160 kg. Additionally, an unbiased non-target analysis was performed following two different strategies for the prioritization of hundreds of potentially relevant unknown masses. While for the first prioritization strategy, only chlorinated compounds were extracted from the mass spectrometer datasets, the second prioritization strategy was performed using a systematic reduction approach between the different sampling sites. Among others, two substances that never had been detected before in this river, namely, the muscle relaxant Tizanidine and the solvent 1,3-Dimethyl-2-imidazolidinone (DMI), were identified and confirmed, and their loads were roughly estimated along the river. PMID:26402878

  12. Polarizing cues.

    PubMed

    Nicholson, Stephen P

    2012-01-01

    People categorize themselves and others, creating ingroup and outgroup distinctions. In American politics, parties constitute the in- and outgroups, and party leaders hold sway in articulating party positions. A party leader's endorsement of a policy can be persuasive, inducing co-partisans to take the same position. In contrast, a party leader's endorsement may polarize opinion, inducing out-party identifiers to take a contrary position. Using survey experiments from the 2008 presidential election, I examine whether in- and out-party candidate cues—John McCain and Barack Obama—affected partisan opinion. The results indicate that in-party leader cues do not persuade but that out-party leader cues polarize. This finding holds in an experiment featuring President Bush in which his endorsement did not persuade Republicans but it polarized Democrats. Lastly, I compare the effect of party leader cues to party label cues. The results suggest that politicians, not parties, function as polarizing cues. PMID:22400143

  13. Polar motion

    NASA Technical Reports Server (NTRS)

    Kolenkiewicz, R.

    1973-01-01

    Tracking of the Beacon Explorer-C satellite by a precision laser system was used to measure the polar motion and solid earth tide. The tidal perturbation of satellite latitude is plotted as variation in maximum latitude in seconds of arc on earth's surface as a function of the date, and polar motion is shown by plotting the variation in latitude of the laser in seconds of arc along the earth's surface as a function of date

  14. Real and hybrid atomic orbitals

    NASA Astrophysics Data System (ADS)

    Cook, D. B.; Fowler, P. W.

    1981-09-01

    It is shown that the Schrödinger equation for the hydrogenlike atom separates in both spheroconal and prolate spheroidal coordinates and that these separations provide a sound theoretical basis for the real and hybrid atomic orbitals. Thus the real and hybrid atomic orbitals have as sound a pedigree as the more familiar complex orbitals based on the separation of the Schrödinger equation in spherical polar coordinates.

  15. Ab-Initio Study on Plutonium Compounds Pu3M (M=Al, Ga, In), PuNp and Elemental Neptunium

    SciTech Connect

    Kutepov, A L

    2005-09-07

    Using spin-polarized relativistic density functional theory the electronic and magnetic structures for the plutonium compounds Pu{sub 3}M(M = Al; Ga; In) and PuNp have been investigated. For the first group of compounds the enhanced hybridization between Pu 5f and p-states of alloying element, as it has been found in spin-polarized calculations, is believed to be the main reason for the higher formation energies obtained in such kind of studies in comparison with the non-spin-polarized case. Also, comparative analysis of the actinides U, Np, Pu, Am, and Cm has been performed based on their electronic and magnetic structure. Some noticeable difference in the calculated magnetic structure was discovered between the actinide with local magnetic moments (Cm) and the actinides (Pu, Am) in which magnetic moments were found only in the calculations.

  16. Varying polarization and spin angular momentum flux of radially polarized beams by anisotropic Kerr media.

    PubMed

    Gu, Bing; Wen, Bo; Rui, Guanghao; Xue, Yuxiong; Zhan, Qiwen; Cui, Yiping

    2016-04-01

    Light fields with structured polarization distribution interacting with structured media will result in many novel optical effects in both the linear and nonlinear regimes. In this work, we report a theoretical investigation of both vectorial self-diffraction behaviors and polarization evolution characteristics of a radially polarized beam induced by anisotropic Kerr nonlinearity. By taking the polarization-orientation dependence of the third-order refractive nonlinearity, we study the far-field vectorial self-diffraction patterns of the radially polarized beam using the vectorial Rayleigh-Sommerfeld formulas. Numerical results reveal that the self-diffraction patterns with a four-fold rotational symmetry exhibit hybrid states of polarization. Moreover, the interaction of radially polarized beams with the anisotropic nonlinear Kerr media leads to the redistribution of the spin angular momentum (SAM) flux in the far-field plane. The presented work opens up new avenues for varying polarization and SAM through anisotropic optical nonlinearity. PMID:27192288

  17. Explaining Polarization Reversals in STEREO Wave Data

    NASA Technical Reports Server (NTRS)

    Breneman, A.; Cattell, C.; Wygant, J.; Kersten, K.; Wilson, L, B., III; Dai, L.; Colpitts, C.; Kellogg, P. J.; Goetz, K.; Paradise, A.

    2012-01-01

    Recently Breneman et al. reported observations of large amplitude lightning and transmitter whistler mode waves from two STEREO passes through the inner radiation belt (L<2). Hodograms of the electric field in the plane transverse to the magnetic field showed that the transmitter waves underwent periodic polarization reversals. Specifically, their polarization would cycle through a pattern of right-hand to linear to left-hand polarization at a rate of roughly 200 Hz. The lightning whistlers were observed to be left-hand polarized at frequencies greater than the lower hybrid frequency and less than the transmitter frequency (21.4 kHz) and right-hand polarized otherwise. Only righthand polarized waves in the inner radiation belt should exist in the frequency range of the whistler mode and these reversals were not explained in the previous paper. We show, with a combination of observations and simulated wave superposition, that these polarization reversals are due to the beating of an incident electromagnetic whistler mode wave at 21.4 kHz and linearly polarized, symmetric lower hybrid sidebands Doppler-shifted from the incident wave by +/-200 Hz. The existence of the lower hybrid waves is consistent with the parametric decay mechanism of Lee and Kuo whereby an incident whistler mode wave decays into symmetric, short wavelength lower hybrid waves and a purely growing (zero-frequency) mode. Like the lower hybrid waves, the purely growing mode is Doppler-shifted by 200 Hz as observed on STEREO. This decay mechanism in the upper ionosphere has been previously reported at equatorial latitudes and is thought to have a direct connection with explosive spread F enhancements. As such it may represent another dissipation mechanism of VLF wave energy in the ionosphere and may help to explain a deficit of observed lightning and transmitter energy in the inner radiation belts as reported by Starks et al.

  18. Structural characterization, phase transition and switchable dielectric behaviors in a new zigzag chain organic-inorganic hybrid compound: [C3H7NH3]2SbI5.

    PubMed

    Mao, Chen-Yu; Liao, Wei-Qiang; Wang, Zhong-Xia; Li, Peng-Fei; Lv, Xing-Hui; Ye, Heng-Yun; Zhang, Yi

    2016-03-28

    A novel zigzag chain organic-inorganic hybrid compound of the general formula R2MI5, [n-C3H7NH3]2[SbI5] (1), was successfully synthesized, in which the n-propylammonium cations were located in the free cavities between the one-dimensional zigzag chains. Systematic characterization was performed to investigate the phase transition of 1. A pair of sharp peaks at 211.8 K (heating) and 203.7 K (cooling) with a hysteresis 8.1 K were observed in the differential scanning calorimetry (DSC) curve, indicating the first-order phase transition behavior of 1. The temperature dependence dielectric measurement demonstrated a step-like change at around 211.8 K, which makes 1 a potential switchable dielectric material. Frequency dependence measurement revealed that the frequency exerts a weak influence on the dielectric permittivity. Further structural analysis shows that both anionic and cationic moieties contribute to the phase transition, accompanied by weak hydrogen bond interactions between cations and the [SbI5]n(2-) chains. PMID:26893146

  19. Process for removing halogenated aliphatic and aromatic compounds from petroleum products

    DOEpatents

    Googin, John M.; Napier, John M.; Travaglini, Michael A.

    1983-01-01

    A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced.

  20. Process for removing halogenated aliphatic and aromatic compounds from petroleum products

    DOEpatents

    Googin, J.M.; Napier, J.M.; Travaglini, M.A.

    1983-09-20

    A process is described for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 1 fig.

  1. Macrocyclic compounds as corrosion inhibitors

    SciTech Connect

    Quraishi, M.A.; Rawat, J.; Ajmal, M.

    1998-12-01

    The influence of three macrocyclic compounds on corrosion of mild steel (MS) in hydrochloric acid (HCl) was investigated using weight loss, potentiodynamic polarization, alternating current (AC) impedance, and hydrogen permeation techniques. All the investigated compounds showed significant efficiencies and reduced permeation of hydrogen through MS in HCl. Inhibition efficiency (IE) varied with the nature and concentrations of the inhibitors, temperature, and concentrations of the acid solutions. The addition of iodide ions (I{sup {minus}}) increased IE of all the tested compounds as a result of the synergistic effect. Potentiodynamic polarization results revealed that macrocyclic compounds acted as mixed inhibitors in 1 M HCl to 5 M HCl. Adsorption on the metal surface obeyed Temkin`s adsorption isotherm. Auger electron spectroscopy (AES) of the polished MS surface, exposed with tetraphenyldithia-octaazacyclotetradeca-hexaene (PTAT) proved adsorption of this compound on the surface through nitrogen and sulfur atoms.

  2. Polar Stratigraphy

    NASA Technical Reports Server (NTRS)

    1999-01-01

    These three images were taken on three different orbits over the north polar cap in April 1999. Each shows a different part of the same ice-free trough. The left and right images are separated by a distance of more than 100 kilometers (62 miles). Note the similar layers in each image.

  3. Political polarization

    PubMed Central

    Dixit, Avinash K.; Weibull, Jörgen W.

    2007-01-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality. PMID:17452633

  4. Controlled switching of ultrafast circular polarization oscillations in spin-polarized vertical-cavity surface-emitting lasers

    SciTech Connect

    Höpfner, Henning Lindemann, Markus; Gerhardt, Nils C.; Hofmann, Martin R.

    2014-01-13

    We demonstrate a scheme for controlled switching of polarization oscillations in spin-polarized vertical-cavity surface-emitting lasers (spin-VCSEL). Under hybrid electrical and optical pumping conditions, our VCSEL devices show polarization oscillations with frequencies far above the VCSEL's electrical modulation bandwidth. Using multiple optical pulses, we are able to excite and amplify these polarization oscillations. When specific phase and amplitude conditions for the optical excitation pulses are met, destructive interference leads to switch-off of the polarization oscillation, enabling the generation of controlled short polarization bursts.

  5. Hybridization schemes for clusters

    NASA Astrophysics Data System (ADS)

    Wales, David J.

    The concept of an optimum hybridization scheme for cluster compounds is developed with particular reference to electron counting. The prediction of electron counts for clusters and the interpretation of the bonding is shown to depend critically upon the presumed hybridization pattern of the cluster vertex atoms. This fact has not been properly appreciated in previous work, particularly in applications of Stone's tensor surface harmonic (TSH) theory, but is found to be a useful tool when dealt with directly. A quantitative definition is suggested for the optimum cluster hybridization pattern based directly upon the ease of interpretation of the molecular orbitals, and results are given for a range of species. The relationship of this scheme to the detailed cluster geometry is described using Löwdin's partitioned perturbation theory, and the success and range of application of TSH theory are discussed.

  6. Cell polarity

    PubMed Central

    Romereim, Sarah M

    2011-01-01

    Despite extensive genetic analysis of the dynamic multi-phase process that transforms a small population of lateral plate mesoderm into the mature limb skeleton, the mechanisms by which signaling pathways regulate cellular behaviors to generate morphogenetic forces are not known. Recently, a series of papers have offered the intriguing possibility that regulated cell polarity fine-tunes the morphogenetic process via orienting cell axes, division planes and cell movements. Wnt5a-mediated non-canonical signaling, which may include planar cell polarity, has emerged as a common thread in the otherwise distinct signaling networks that regulate morphogenesis in each phase of limb development. These findings position the limb as a key model to elucidate how global tissue patterning pathways direct local differences in cell behavior that, in turn, generate growth and form. PMID:22064549

  7. Polar Textures

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03646 Polar Textures

    This VIS image shows part of the south polar region. The ejecta from the relatively young crater covers the rougher textured polar surface.

    Image information: VIS instrument. Latitude 81S, Longitude 54.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  8. EVALUATION OF AN ANION EXCHANGE RESIN FOR SAMPLING AMBIENT LEVEL PHENOLIC COMPOUNDS

    EPA Science Inventory

    The determination of human exposure to polar volatile and semivolatile organic compounds is an area of increasing importance to EPA. ince the bioavailability of many polar compounds is greater than for relatively non-polar compounds, methods are needed for the selective sampling ...

  9. Flare Hybrids

    NASA Astrophysics Data System (ADS)

    Tomczak, M.; Dubieniecki, P.

    2015-12-01

    On the basis of the Solar Maximum Mission observations, Švestka ( Solar Phys. 121, 399, 1989) introduced a new class of flares, the so-called flare hybrids. When they start, they look like typical compact flares (phase 1), but later on, they look like flares with arcades of magnetic loops (phase 2). We summarize the characteristic features of flare hybrids in soft and hard X-rays as well as in the extreme ultraviolet; these features allow us to distinguish flare hybrids from other flares. In this article, additional energy release or long plasma cooling timescales are suggested as possible causes of phase 2. We estimate the frequency of flare hybrids, and study the magnetic configurations favorable for flare hybrid occurrence. Flare hybrids appear to be quite frequent, and the difference between the lengths of magnetic loops in the two interacting loop systems seem to be a crucial parameter for determining their characteristics.

  10. Hybrid superconducting magnetic suspensions

    SciTech Connect

    Tixador, P.; Hiebel, P.; Brunet, Y.

    1996-07-01

    Superconductors, especially high T{sub c} ones, are the most attractive materials to design stable and fully passive magnetic suspensions which have to control five degrees of freedom. The hybrid superconducting magnetic suspensions present high performances and a simple cooling mode. They consist of a permanent magnet bearing, stabilized by a suitable magnet-superconductor structure. Several designs are given and compared in terms of forces and stiffnesses. The design of the magnet bearing plays an important part. The superconducting magnetic bearing participates less in levitation but must provide a high stabilizing stiffness. This is achieved by the magnet configuration, a good material in term of critical current density and field cooling. A hybrid superconducting suspension for a flywheel is presented. This system consists of a magnet thrust bearing stabilized by superconductors interacting with an alternating polarity magnet structure. First tests and results are reported. Superconducting materials are magnetically melt-textured YBaCuO.

  11. Polar Landforms

    NASA Technical Reports Server (NTRS)

    2005-01-01

    10 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows eroded remnants of carbon dioxide ice in the south polar residual cap of Mars. The scarps that outline each small mesa have retreated about 3 meters (10 feet) per Mars year since MGS began orbiting the red planet in 1997.

    Location near: 87.0oS, 31.9oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  12. Towards development of lignin reinforced elastomeric compounds with reduced energy dissipation

    NASA Astrophysics Data System (ADS)

    Bahl, Kushal

    This research deals with development of lignin as reinforcing filler for elastomeric compounds. Lignins are naturally abundant and cost competitive wood derivatives possessing strong mechanical properties and offering reactive functional groups on their surfaces. The presence of the functional groups imparts polarity to the lignin molecules and makes them incompatible with non-polar elastomers. Also, the large particle size of lignin does not produce desired mechanical reinforcement. The present study deals with solving the outstanding issues associated with the use of lignin as fillers for polymeric compounds. In addition, the work specifically focuses on producing rubber compounds with reduced energy dissipation via partial replacement of carbon black with lignin. The first part of this study is devoted to suppression of the polarity of lignin and achievement of compatibility with rubber matrix via modification of lignosulfonates (LS) with cyclohexylamine (CA). CA reduces the polarity of lignin via interactions originating from proton transfer and hydrogen bonding. X-ray Photoelectron Spectroscopy (XPS) confirms the attachment of CA on the surfaces of lignin. The mechanical properties of rubber compounds increase substantially along with improvement in cure properties and increase in crosslink density in the presence of LS particles modified with CA. The tensile strength and storage modulus show an increase by 45% and 41% respectively. The values of the 100% modulus and elongation at break also improve by 35% and 60% respectively. The second part of this study exploits the non-covalent interactions between lignin and carbon black (CB) for the design of novel hybrid filler particles exhibiting lower energy loss in rubber compounds. The hybrid fillers offer unique morphology consisting of coating layers of lignin on carbon black particle aggregates. It is found that such coating layers are formed due to pi-pi interactions between lignin and carbon black. Raman

  13. Compound matrices

    NASA Astrophysics Data System (ADS)

    Kravvaritis, Christos; Mitrouli, Marilena

    2009-02-01

    This paper studies the possibility to calculate efficiently compounds of real matrices which have a special form or structure. The usefulness of such an effort lies in the fact that the computation of compound matrices, which is generally noneffective due to its high complexity, is encountered in several applications. A new approach for computing the Singular Value Decompositions (SVD's) of the compounds of a matrix is proposed by establishing the equality (up to a permutation) between the compounds of the SVD of a matrix and the SVD's of the compounds of the matrix. The superiority of the new idea over the standard method is demonstrated. Similar approaches with some limitations can be adopted for other matrix factorizations, too. Furthermore, formulas for the n - 1 compounds of Hadamard matrices are derived, which dodge the strenuous computations of the respective numerous large determinants. Finally, a combinatorial counting technique for finding the compounds of diagonal matrices is illustrated.

  14. Polarization response of nanowires à la carte.

    PubMed

    Casadei, Alberto; Llado, Esther Alarcon; Amaduzzi, Francesca; Russo-Averchi, Eleonora; Rüffer, Daniel; Heiss, Martin; Dal Negro, Luca; Fontcuberta i Morral, Anna

    2015-01-01

    Thanks to their special interaction with light, semiconductor nanowires have opened new avenues in photonics, quantum optics and solar energy harvesting. One of the major challenges for their full technological deployment has been their strong polarization dependence in light absorption and emission. In the past, metal nanostructures have been shown to have the ability to modify and enhance the light response of nanoscale objects. Here we demonstrate that a hybrid structure formed by GaAs nanowires with a highly dense array of bow-tie antennas is able to modify the polarization response of a nanowire. As a result, the increase in light absorption for transverse polarized light changes the nanowire polarization response, including the polarization response inversion. This work will open a new path towards the widespread implementation of nanowires applications such as in photodetection, solar energy harvesting and light emission. PMID:25564366

  15. Polarization response of nanowires à la carte

    PubMed Central

    Casadei, Alberto; Llado, Esther Alarcon; Amaduzzi, Francesca; Russo-Averchi, Eleonora; Rüffer, Daniel; Heiss, Martin; Negro, Luca Dal; Morral, Anna Fontcuberta i

    2015-01-01

    Thanks to their special interaction with light, semiconductor nanowires have opened new avenues in photonics, quantum optics and solar energy harvesting. One of the major challenges for their full technological deployment has been their strong polarization dependence in light absorption and emission. In the past, metal nanostructures have been shown to have the ability to modify and enhance the light response of nanoscale objects. Here we demonstrate that a hybrid structure formed by GaAs nanowires with a highly dense array of bow-tie antennas is able to modify the polarization response of a nanowire. As a result, the increase in light absorption for transverse polarized light changes the nanowire polarization response, including the polarization response inversion. This work will open a new path towards the widespread implementation of nanowires applications such as in photodetection, solar energy harvesting and light emission. PMID:25564366

  16. Polar ozone

    NASA Technical Reports Server (NTRS)

    Solomon, S.; Grose, W. L.; Jones, R. L.; Mccormick, M. P.; Molina, Mario J.; Oneill, A.; Poole, L. R.; Shine, K. P.; Plumb, R. A.; Pope, V.

    1990-01-01

    The observation and interpretation of a large, unexpected ozone depletion over Antarctica has changed the international scientific view of stratospheric chemistry. The observations which show the veracity, seasonal nature, and vertical structure of the Antarctic ozone hole are presented. Evidence for Arctic and midlatitude ozone loss is also discussed. The chemical theory for Antarctic ozone depletion centers around the occurrence of polar stratospheric clouds (PSCs) in Antarctic winter and spring; the climatology and radiative properties of these clouds are presented. Lab studies of the physical properties of PSCs and the chemical processes that subsequently influence ozone depletion are discussed. Observations and interpretation of the chemical composition of the Antarctic stratosphere are described. It is shown that the observed, greatly enhanced abundances of chlorine monoxide in the lower stratosphere are sufficient to explain much if not all of the ozone decrease. The dynamic meteorology of both polar regions is given, interannual and interhemispheric variations in dynamical processes are outlined, and their likely roles in ozone loss are discussed.

  17. Polar Markings

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA02155 Polar Markings

    These bright and dark markings occurred near the end of summer in the south polar region. The dark material is likely dust that has been freed of frost cover.

    Image information: VIS instrument. Latitude -76.3N, Longitude 84.9E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  18. Polar Layers

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA02153 Polar Layers

    This image of the south polar region shows layered material. It is not known if the layers are formed yearly or if they form over the period of 10s to 100s of years or more.

    Image information: VIS instrument. Latitude -80.3N, Longitude 296.2E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  19. Polar Ridges

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03662 Polar Ridges

    This ridge system is located in the south polar region.

    Image information: VIS instrument. Latitude -81.7N, Longitude 296.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  20. Polar Textures

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03638 Polar Textures

    This image illustrates the variety of textures that appear in the south polar region during late summer.

    Image information: VIS instrument. Latitude 80.5S, Longitude 57.9E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  1. Polar Terrains

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03577 Polar Terrains

    The region surrounding the South Polar Cap contains many different terrain types. This image shows both etched terrain and a region of 'mounds'.

    Image information: VIS instrument. Latitude 75S, Longitude 286.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  2. Hybrid reflection type metasurface of nano-antennas designed for optical needle field generation

    NASA Astrophysics Data System (ADS)

    Wang, Shiyi; Zhan, Qiwen

    2015-03-01

    We propose a reflection type metal-insulator-metal (MIM) metasurface composed of hybrid optical antennas for comprehensive spatial engineering the properties of optical fields. Its capability is illustrated with an example to create a radially polarized vectorial beam for optical needle field generation. Functioning as local quarter-wave-plates (QWP), the MIM metasurface is designed to convert circularly polarized incident into local linear polarization to create an overall radial polarization with corresponding binary phases and desired normalized amplitude modulation ranged from 0.07 to 1. To obtain enough degrees of freedom, the optical-antenna layer comprises periodic arrangements of double metallic nano-bars with perpendicular placement and single nano-bars respectively for different amplitude modulation requirements. Both of the antennas enable to introduce π/2 retardation while reaching the desired modulation range both for phase and amplitude. Through adjusting the antennas' geometry and array carefully, we shift the gap-surface plasmon resonances facilitated by optical antennas to realize the manipulation of vectorial properties. Designed at 1064 nm wavelength, the particularly generated vectorial light output can be further tightly focused by a high numerical aperture objective to obtain longitudinally polarized flat-top focal field. The so-called optical needle field is a promising candidate for novel applications that transcend disciplinary boundaries. The proposed metasurface establishes a new class of compact optical components based on nano-scale structures, leading to compound functions for vectorial light generation.

  3. Histidine-modified organic-silica hybrid monolithic column for mixed-mode per aqueous and ion-exchange capillary electrochromatography.

    PubMed

    Tang, Sheng; Liu, Shujuan; Liang, Xiaojing; Tang, Xiaofen; Wu, Xingcai; Guo, Yong; Liu, Xia; Jiang, Shengxiang

    2015-06-01

    A novel organic-silica hybrid monolith was prepared through the binding of histidine onto the surface of monolithic matrix for mixed-mode per aqueous and ion-exchange capillary electrochromatography. The imidazolium and amino groups on the surface of the monolithic stationary phase were used to generate an anodic electro-osmotic flow as well as to provide electrostatic interaction sites for the charged compounds at low pH. Typical per aqueous chromatographic behavior was observed in water-rich mobile phases. Various polar and hydrophilic analytes were selected to evaluate the characteristics and chromatographic performance of the obtained monolith. Under per aqueous conditions, the mixed-mode mechanism of hydrophobic and ion-exchange interactions was observed and the resultant monolithic column proved to be very versatile for the efficient separations of these polar and hydrophilic compounds (including amides, nucleosides and nucleotide bases, benzoic acid derivatives, and amino acids) in highly aqueous mobile phases. The successful applications suggested that the histidine-modified organic-silica hybrid monolithic column could offer a wide range of retention behaviors and flexible selectivities toward polar and hydrophilic compounds. PMID:25845702

  4. Polar Barchans

    NASA Technical Reports Server (NTRS)

    2004-01-01

    20 July 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark, barchan sand dunes of the north polar region of Mars. Barchan dunes are simple, rounded forms with two horns that extend downwind. Inequalities in local wind patterns may result in one horn being extended farther than the other, as is the case for several dunes in this image. The image also shows several barchans may merge to form a long dune ridge. The horns and attendant slip faces on these dunes indicate wind transport of sand from the upper left toward the lower right. The image is located near 77.6oN, 103.6oW. The picture covers an area about 3 km (1.9 mi) wide; sunlight illuminates the scene from the lower left.

  5. Polar Polygons

    NASA Technical Reports Server (NTRS)

    2004-01-01

    26 December 2003 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture displays polygons outlined by cracks in the martian south polar region. This southern summer view was acquired in October 2003 and is located near 86.9oS, 170.6oW. Polygons similar in size and shape to these are common in the arctic and antarctic regions of Earth. On Earth, they indicate the presence (or the past presence) of ground ice and the freeze-thaw cycles that accompany this ice. On Mars, whether ground ice was responsible for these landforms is uncertain, but their presence is suggestive that ground ice may exist or may once have existed in this region. The picture covers an area 3 km (1.9 mi) wide. Sunlight illuminates the scene from the upper left.

  6. Process for removing halogenated aliphatic and aromatic compounds from petroleum products. [Polychlorinated biphenyls; methylene chloride; perchloroethylene; trichlorofluoroethane; trichloroethylene; chlorobenzene

    DOEpatents

    Googin, J.M.; Napier, J.M.; Travaglini, M.A.

    1982-03-31

    A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contracting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible polyhydroxy compound, such as, water, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds in the low polar or nonpolar solvent by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered for recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 2 tables.

  7. Stellarator hybrids

    SciTech Connect

    Furth, H.P.; Ludescher, C.

    1984-08-01

    The present paper briefly reviews the subject of tokamak-stellarator and pinch-stellarator hybrids, and points to two interesting new possibilities: compact-torus-stellarators and mirror-stellarators.

  8. Active and Passive Hybrid Sensor

    NASA Technical Reports Server (NTRS)

    Carswell, James R.

    2010-01-01

    A hybrid ocean wind sensor (HOWS) can map ocean vector wind in low to hurricane-level winds, and non-precipitating and precipitating conditions. It can acquire active and passive measurements through a single aperture at two wavelengths, two polarizations, and multiple incidence angles. Its low profile, compact geometry, and low power consumption permits installation on air craft platforms, including high-altitude unmanned aerial vehicles (UAVs).

  9. Photoinduced mass transport in azo compounds

    NASA Astrophysics Data System (ADS)

    Klismeta, K.; Teteris, J.; Aleksejeva, J.

    2013-12-01

    The photoinduced changes of optical properties in azobenzene containing compound thin films were studied under influence of polarized and non-polarized 532 nm laser light. Under influence of light azo compounds experience trans-cis isomerisation process, that can be observed in the absorbance spectrum of the sample. If the light is linearly polarized, molecules align perpendicularly to the electric field vector and as a result photoinduced dichroism and birefringence is obtained. If a known lateral polarization modulation of the light beam is present, mass transport of the azobenzene containing compound occurs. By measuring the surface relief with a profilometer the direction of mass transport can be determined. The studies of this work show that direct holographic recording of surface relief gratings can be used in optoelectronics, telecommunications and data storage.

  10. Spin and orbital orderings behind multiferroicity in delafossite and related compounds.

    PubMed

    Terada, Noriki

    2014-11-12

    Coupling between noncollinear magnetic ordering and ferroelectricicty in magnetoelectric multiferroics has been extensively studied in the last decade. Delafossite family compounds with triangular lattice structure provide a great opportunity to study the coupling between spin and electric dipole in multiferroics due to the variety of magnetic phases with different symmetry. This review introduces the magnetic and ferroelectric phase transitions in delafossite ferrites, CuFe(1-x)X(x)O(2) (X = Al, Ga), AgFeO(2) and the related compound α-NaFeO(2). In CuFeO(2), the ferroelectric phase appears under a magnetic field or chemical substitution. The proper screw magnetic ordering with the magnetic point group 21', which has been determined by detailed analysis in neutron diffraction experiments, induces the ferroelectric polarization along the monoclinic b axis in CuFeO2. The cycloidal magnetic orderings are realized in AgFeO(2) and α-NaFeO(2), which are of the point group m1' allowing polarization in the ac plane. The emergence of ferroelectric polarization can be explained by both the extended inverse Dzyaloshinsky-Moriya effect and the d − p hybridization mechanism. These mechanisms are supported by experimental evidence in CuFe(1-x)Ga(x)O2. The polarized neutron diffraction experiment demonstrated one-to-one correspondence between ferroelectric polarization and spin helicity, S(i) × S(j). The incommensurate orbital ordering with 2 Q wave vector, observed by the soft x-ray resonant diffraction experiment, proved that the spin-orbit interaction ties spin and orbital orders to each other, playing a crucial role for the emergence of ferroelectricity in CuFe(1-x)Ga(x)O2. PMID:25336518

  11. Polarized internal target apparatus

    DOEpatents

    Holt, R.J.

    1984-10-10

    A polarized internal target apparatus with a polarized gas target of improved polarization and density (achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms) is described.

  12. Polarized internal target apparatus

    DOEpatents

    Holt, Roy J.

    1986-01-01

    A polarized internal target apparatus with a polarized gas target of improved polarization and density achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms.

  13. Coumarin hybrids as novel therapeutic agents.

    PubMed

    Sandhu, Sonali; Bansal, Yogita; Silakari, Om; Bansal, Gulshan

    2014-08-01

    Naturally occurring coumarins, having wide spectrum of activities such as antioxidant, anti-inflammatory, anticancer, MAO-B inhibitory and antimicrobial, are frequently used by the researchers to develop novel synthetic and semisynthetic coumarin based therapeutic agents. Many of these agents are hybrid molecules, which are designed through concept of molecular hybridization and have shown multiple pharmacological activities. This multifunctional attribute of these hybrid compounds makes them potential drug candidates for the treatment of multifactorial diseases such as cancer, Alzheimer's disease, metabolic syndromes, AIDS, malaria, and cardiovascular diseases. The present review compiles research reports on development of different coumarin hybrids, classify these on the basis of their therapeutic uses and propose structure-activity relationships. It is intended to help medicinal chemist in designing and synthesizing novel and potent hybrid compounds for the treatment of different disorders. PMID:24934993

  14. Characterization of polyphenolic metabolites in grape hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The composition and content of polyphenolic compounds in the berries of 48 hybrid grapes (Vitis) were characterized for two consecutive years. A total of 48 polyphenolic compounds including 28 anthocyanins, 2 hydroxybenzoic acids, 6 hydroxycinnamic derivatives, 6 flavonols and 6 flavanols were ident...

  15. Experimental demonstration of hybrid improper ferroelectricity and the presence of abundant charged walls in (Ca,Sr)3Ti2O7 crystals.

    PubMed

    Oh, Yoon Seok; Luo, Xuan; Huang, Fei-Ting; Wang, Yazhong; Cheong, Sang-Wook

    2015-04-01

    On the basis of successful first-principles predictions of new functional ferroelectric materials, a number of new ferroelectrics have been experimentally discovered. Using trilinear coupling of two types of octahedron rotation, hybrid improper ferroelectricity has been theoretically predicted in ordered perovskites and the Ruddlesden-Popper compounds (Ca3Ti2O7, Ca3Mn2O7 and (Ca/Sr/Ba)3(Sn/Zr/Ge)2O7). However, the ferroelectricity of these compounds has never been experimentally confirmed and even their polar nature has been under debate. Here we provide the first experimental demonstration of room-temperature switchable polarization in bulk crystals of Ca3Ti2O7, as well as Sr-doped Ca3Ti2O7. Furthermore, (Ca, Sr)3Ti2O7 is found to exhibit an intriguing ferroelectric domain structure resulting from orthorhombic twins and (switchable) planar polarization. The planar domain structure accompanies abundant charged domain walls with conducting head-to-head and insulating tail-to-tail configurations, which exhibit a conduction difference of two orders of magnitude. These discoveries provide new research opportunities, not only for new stable ferroelectrics of Ruddlesden-Popper compounds, but also for meandering conducting domain walls formed by planar polarization. PMID:25581628

  16. Polarization transfer NMR imaging

    DOEpatents

    Sillerud, Laurel O.; van Hulsteyn, David B.

    1990-01-01

    A nuclear magnetic resonance (NMR) image is obtained with spatial information modulated by chemical information. The modulation is obtained through polarization transfer from a first element representing the desired chemical, or functional, information, which is covalently bonded and spin-spin coupled with a second element effective to provide the imaging data. First and second rf pulses are provided at first and second frequencies for exciting the imaging and functional elements, with imaging gradients applied therebetween to spatially separate the nuclei response for imaging. The second rf pulse is applied at a time after the first pulse which is the inverse of the spin coupling constant to select the transfer element nuclei which are spin coupled to the functional element nuclei for imaging. In a particular application, compounds such as glucose, lactate, or lactose, can be labeled with .sup.13 C and metabolic processes involving the compounds can be imaged with the sensitivity of .sup.1 H and the selectivity of .sup.13 C.

  17. Polar narcosis: Designing a suitable training set

    SciTech Connect

    Ramos, E.U.; Vaes, W.H.J.; Verhaar, H.J.M.; Hermens, L.M.

    1995-12-31

    Substituted phenols, anilines, pyridines and nitrobenzenes can be classified as polar narcotics. These chemicals differ from non-polar narcotic compounds not only in that they exhibit a 5 to 10 times higher toxicity, but also in their Fish Acute Toxic Syndromes, together suggesting a different mode of action. For 97 polar narcotics, which are not ionized under physiological conditions, 11 physico-chemical and quantum-chemical descriptors were calculated. Using Principal Components Analysis 91% of the total variance could be explained by three Principal Components, which were subsequently used as factors in a Statistical Design. Eleven compounds were selected based on a two-level full factorial design, including three compounds near the center (2{sup 3} + 3). QSARs were developed for both, the design set and a set of 63 polar narcotics for which guppy and/or fathead minnow data were available in the literature. Both QSAR, based on PLS, resulted in good models (R{sup 2} = 0.96 and Q{sup 2} = 0.8{sup 2}; R{sup 2}= 0.86 and Q{sup 2} = 0.83 respectively) and gave similar Pseudo Regression Coefficients. In addition the model based on the designed chemicals was able to predict the toxicity of the 63 compounds (R{sup 2} = 0.85). These results show that these 11 chemicals are a well-balanced set for further studies of polar narcosis.

  18. Mutagenicity of oxaspiro compounds with Salmonella.

    PubMed

    Sinsheimer, J E; Chakraborty, P K; Messerly, E A; Gaddamidi, V

    1989-10-01

    The spiro attachment of an epoxide group to a tetrahydropyran ring in the trichothecene mycotoxins has prompted this study of the mutagenicity and alkylation rates of the trichothecene, anguidine, and 5 related model oxaspiro compounds. While the model compounds were weak alkylating agents of 4-(4-nitrobenzyl)pyridine as a test nucleophile, anguidine lacks such activity. Also, while mutagenicity was not established for anguidine in Salmonella TA100, 3 of the oxaspiro compounds were weakly mutagenic and 2 compounds were toxic to the bacteria. The toxicity and mutagenicity of the model compounds are more related to their polarity than to their alkylation rates. PMID:2677708

  19. Polar Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 3 May 2004 This nighttime visible color image was collected on January 1, 2003 during the Northern Summer season near the North Polar Troughs.

    This daytime visible color image was collected on September 4, 2002 during the Northern Spring season in Vastitas Borealis. The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 79, Longitude 346 East (14 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with

  20. Penta prism laser polarizer.

    PubMed

    Lotem, H; Rabinovitch, K

    1993-04-20

    A novel type of laser prism polarizer is proposed. The polarizer is characterized by a high transmission efficiency, a high optical damage threshold, and a high extinction ratio. The polarizer is shaped like a regular penta prism and, thus, it is a constant deviation angle device. Polarization effects occur upon the two internal cascade reflections in the prism. Anisotropic and Isotropic types of the polarizer are discussed. The isotropic polarizer is a prism made of a high refractive-index glass coated by multilayer polarization-type dielectric coatings. Efficient s-state polarization is obtained because of p-state leakage upon the two internal cascade reflections. The anisotropic polarizer is made of a birefringent crystal in which angular polarization splitting is obtained by the bireflectance (double-reflection) effect. Fanning of a laser beam into up to eight polarized beams is possible in a prism made of a biaxial crystal. PMID:20820335

  1. Sky light polarization detection with linear polarizer triplet in light field camera inspired by insect vision.

    PubMed

    Zhang, Wenjing; Cao, Yu; Zhang, Xuanzhe; Liu, Zejin

    2015-10-20

    Stable information of a sky light polarization pattern can be used for navigation with various advantages such as better performance of anti-interference, no "error cumulative effect," and so on. But the existing method of sky light polarization measurement is weak in real-time performance or with a complex system. Inspired by the navigational capability of a Cataglyphis with its compound eyes, we introduce a new approach to acquire the all-sky image under different polarization directions with one camera and without a rotating polarizer, so as to detect the polarization pattern across the full sky in a single snapshot. Our system is based on a handheld light field camera with a wide-angle lens and a triplet linear polarizer placed over its aperture stop. Experimental results agree with the theoretical predictions. Not only real-time detection but simple and costless architecture demonstrates the superiority of the approach proposed in this paper. PMID:26560386

  2. Deep eutectic solvents as novel extraction media for phenolic compounds from model oil.

    PubMed

    Gu, Tongnian; Zhang, Mingliang; Tan, Ting; Chen, Jia; Li, Zhan; Zhang, Qinghua; Qiu, Hongdeng

    2014-10-11

    Deep eutectic solvents (DES) as a new kind of green solvent were used for the first time to excellently extract phenolic compounds from model oil. It was also proved that DES could be used to extract other polar compounds from non-polar or weakly-polar solvents by liquid-phase microextraction. PMID:25144155

  3. Thermal expansion, polarization and phase diagrams of Ba1-yBi2y/3Ti1-xZrxO3 and Ba1-yLayTi1-y/4O3 compounds

    NASA Astrophysics Data System (ADS)

    Gorev, Michail; Bondarev, Vitaly; Flerov, Igor; Maglione, Mario; Simon, Annie; Sciau, Philippe; Boulos, Madona; Guillemet-Fritsch, Sophie

    2009-02-01

    The thermal expansion properties of the ceramic compositions Ba1-yLayTi1-y/4O3 (y = 0.0, 0.026, 0.036, 0.054) and Ba1-yBi2y/3Ti1-xZrxO3 (y = 0.10; x = 0.0, 0.04, 0.05, 0.10, 0.15) were determined in the temperature range 120-700 K. We report the temperature-dependent measurements of the strain, thermal expansion coefficient and the magnitude of root mean square polarization. The results obtained are discussed together with the data on the structure and dielectric properties.

  4. High stability silver nanoparticles-graphene/poly(ionic liquid)-based chemoresistive sensors for volatile organic compounds' detection.

    PubMed

    Tung, Tran Thanh; Castro, Mickael; Kim, Tae Young; Suh, Kwang S; Feller, Jean-Francois

    2014-06-01

    Hybrids of silver nanoparticle-decorated reduced graphene oxide (Ag-RGO) have been prepared with the use of poly(ionic liquid) (PIL) as a versatile capping agent to develop volatile organic compound (VOC) sensors. The hybrid materials of Ag-RGO/PIL were assembled into three-dimensional-laminated nanostructures, where spherical Ag nanoparticles with diameters between 50 and 300 nm were homogeneously distributed on the graphene sheets and interspaced between them. Ag-RGO/PIL sensors were fabricated by spray layer-by-layer technique and used to detect a set of polar (methanol, ethanol, methyl acetate, acetone and water) and non-polar (chloroform, dichlorobenzene, toluene and styrene) organic vapours. Much higher sensitivity and discriminability were obtained for polar vapours although non-polar ones could also be detected. In comparison with either simple reduced graphene oxide or carbon nanotubes (CNT) functionalised by PIL, the hybrid Ag-RGO/PIL-based sensors showed superior performances in terms of sensitivity, selectivity, stability and high reliability. For example, a signal-to-noise ratio up to 168 was obtained for 1 ppm of methanol and signals drift between two experiments spaced out in the time of 3 months was less than 3%. It is expected that by extrapolation, a limit of detection at the parts per billion level can be reached. These results are promising to design e-noses based on high stability chemoresistive sensors for emerging applications such as anticipated diagnostic of food degradation or diseases by the analysis of VOC, some of them being in this case considered as biomarkers. PMID:24414740

  5. Polarized Light in Astronomy.

    ERIC Educational Resources Information Center

    King, D. J.

    1983-01-01

    The application of very sensitive electronic detecting devices during the last decade has revolutionized and revitalized the study of polarization in celestial objects. The nature of polarization, how polaroids work, interstellar polarization, dichroic filters, polarization by scattering, and modern polarimetry are among the topics discussed. (JN)

  6. Linearly polarized fiber amplifier

    DOEpatents

    Kliner, Dahv A.; Koplow, Jeffery P.

    2004-11-30

    Optically pumped rare-earth-doped polarizing fibers exhibit significantly higher gain for one linear polarization state than for the orthogonal state. Such a fiber can be used to construct a single-polarization fiber laser, amplifier, or amplified-spontaneous-emission (ASE) source without the need for additional optical components to obtain stable, linearly polarized operation.

  7. Nondiffracting transversally polarized beam.

    PubMed

    Yuan, G H; Wei, S B; Yuan, X-C

    2011-09-01

    Generation of a nondiffracting transversally polarized beam by means of transmitting an azimuthally polarized beam through a multibelt spiral phase hologram and then highly focusing by a high-NA lens is presented. A relatively long depth of focus (∼4.84λ) of the electric field with only radial and azimuthal components is achieved. The polarization of the wavefront near the focal plane is analyzed in detail by calculating the Stokes polarization parameters. It is found that the polarization is spatially varying and entirely transversally polarized, and the polarization singularity disappears at the beam center, which makes the central bright channel possible. PMID:21886250

  8. Changing polar environments: Interdisciplinary challenges

    NASA Astrophysics Data System (ADS)

    Shepson, Paul B.; Ariya, Parisa A.; Deal, Clara J.; Donaldson, D. James; Douglas, Thomas A.; Loose, Brice; Maksym, Ted; Matrai, Patricia A.; Russell, Lynn M.; Saenz, Benjamin; Stefels, Jacqueline; Steiner, Nadja

    2012-03-01

    In the past few decades, there has been enormous growth in scientific studies of physical, chemical, and biological interactions among reservoirs in polar regions. This has come, in part, as a result of a few significant discoveries: There is dramatic halogen chemistry that occurs on and above the sea ice in the springtime that destroys lower tropospheric ozone and mercury [Simpson et al., 2007; Steffen et al., 2008], the sunlit snowpack is very photochemically active [Grannas et al., 2007], biology as a source of organic compounds plays a pivotal role in these processes, and these processes are occurring in the context of rapidly changing polar regions under climate feedbacks that are as of yet not fully understood [Serreze and Barry, 2011]. Stimulated by the opportunities of the International Polar Year (IPY, 2007-2009), a number of large-scale field studies in both polar environments have been undertaken, aimed at the study of the complex biotic and abiotic processes occurring in all phases (see Figure 1). Sea ice plays a critical role in polar environments: It is a highly reflective surface that interacts with radiation; it provides a habitat for mammals and micro-organisms alike, thus playing a key role in polar trophic processes and elemental cycles; and it creates a saline environment for chemical processes that facilitate release of halogenated gases that contribute to the atmosphere's ability to photochemically cleanse itself in an otherwise low-radiation environment. Ocean-air and sea ice-air interfaces also produce aerosol particles that provide cloud condensation nuclei.

  9. Multipurpose Compound

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  10. Crossed elliptical polarization undulator

    SciTech Connect

    Sasaki, Shigemi

    1997-05-01

    The first switching of polarization direction is possible by installing two identical helical undulators in series in a same straight section in a storage ring. By setting each undulator in a circular polarization mode in opposite handedness, one can obtain linearly polarized radiation with any required polarization direction depending on the modulator setting between two undulators. This scheme can be used without any major degradation of polarization degree in any low energy low emittance storage ring.

  11. Polarization-balanced beamsplitter

    DOEpatents

    Decker, D.E.

    1998-02-17

    A beamsplitter assembly is disclosed that includes several beamsplitter cubes arranged to define a plurality of polarization-balanced light paths. Each polarization-balanced light path contains one or more balanced pairs of light paths, where each balanced pair of light paths includes either two transmission light paths with orthogonal polarization effects or two reflection light paths with orthogonal polarization effects. The orthogonal pairing of said transmission and reflection light paths cancels polarization effects otherwise caused by beamsplitting. 10 figs.

  12. Polarization-balanced beamsplitter

    DOEpatents

    Decker, Derek E.

    1998-01-01

    A beamsplitter assembly that includes several beamsplitter cubes arranged to define a plurality of polarization-balanced light paths. Each polarization-balanced light path contains one or more balanced pairs of light paths, where each balanced pair of light paths includes either two transmission light paths with orthogonal polarization effects or two reflection light paths with orthogonal polarization effects. The orthogonal pairing of said transmission and reflection light paths cancels polarization effects otherwise caused by beamsplitting.

  13. Interspecific transplantation of polar plasm between Drosophila embryos

    PubMed Central

    1976-01-01

    Posterior polar plasm of the Drosophila egg has been shown to function autonomously in germ cell determination after transplantation to either the anterior or mid-ventral region of the early embryo. By means of similar transplantations, we have tested the ability of polar plasm of Drosophila immigrans to induce the formation of pole cells in a Drosophila melanogaster embryo. After the transplantation of polar plasm, "hybrid" pole cells were found in which both pole cell-specific organelles, the polar granules and nuclear body, were structurally similar to those characteristic of the transplanted cytoplasm. In order to determine whether these hybrid cells can function as germ cell precursors, these cells were transplanted to the posterior tip of genetically marked embryos. Approximately 5% of the flies obtained from embryos receiving potential pole cells produce offspring derived from the induced pole cells. This result demonstrates that polar plasm can function in interspecific species combinations and indicates that the molecular mechanisms of germ cell determination are conservative in evolution. Finally, in order to test whether there is any evidence for cytoplasmic inheritance of polar granules, embryos derived from hybrid pole cells were examined for their polar granule morphology. The fine structure of the granules conformed to that of the nucleus. Thus, no evidence was found for the cytoplasmic inheritance of these particular organelles. PMID:820700

  14. Ionic liquid-based one-step micellar extraction of multiclass polar compounds from hawthorn fruits by ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry.

    PubMed

    Hu, Shuai-Shuai; Yi, Ling; Li, Xing-Ying; Cao, Jun; Ye, Li-Hong; Cao, Wan; Da, Jian-Hua; Dai, Han-Bin; Liu, Xiao-Juan

    2014-06-11

    An ionic liquid (IL)-based one-step micellar extraction procedure was developed for the extraction of multiclass polar analytes (protocatechuic acid, chlorogenic acid, epicatechin, hyperoside, isoquercitrin, quercetin) from hawthorn fruits and their determination using ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF/MS). Compared to conventional organic solvent extractions, this newly proposed method was much easier, more sensitive, environmentally friendly, and effective as well. Several important parameters influencing the micellar extraction efficiency are discussed, such as selection of ILs, surfactant concentration, and extraction time. Under the optimal conditions, good linearity was achieved for each analyte with correlation coefficients (r(2)) ranging from 0.9934 to 0.9999, and the recovery values ranged from 89.3 to 106% with relative standard deviations lower than 5.5%. Results suggest that the IL-based one-step micellar extraction could be an alternative and promising means in future food analysis. PMID:24845828

  15. Neutron polarizers based on polarized ^3He

    NASA Astrophysics Data System (ADS)

    Gentile, T. R.; Jones, G. L.; Thompson, A. K.; Fei, X.; Keith, C. D.; Rich, D.; Snow, W. M.; Penttila, S.

    1997-10-01

    Research is underway at NIST, Indiana Univ., and LANL to develop neutron polarizers and analyzers based on polarized ^3He. Such devices, which rely on the strong spin dependence of the neutron capture cross section by polarized ^3He, have applications in weak interaction physics and materials science. In addition, the technology for polarized ^3He production is directly applicable to polarized gas MRI of lungs, and polarized targets. Our program, which includes both the spin-exchange and metastability-exchange optical pumping methods, will be reviewed. Spin-exchange has been used to analyze a polarized cold neutron beam at NIST, and also for lung imaging in collaboration with the Univ. of Pennsylvania. In the metastable method, the ^3He is polarized at low pressure, and must be substantially compressed. A piston compressor has been designed for this goal at Indiana Univ. and is under construction. At NIST we have compressed polarized gas using an apparatus that is based on a modified commercial diaphragm pump.

  16. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2001-01-01

    Seawater and natural brines accounted for about 63% of US magnesium compounds production during 2000. Premier Services in Florida, Dow Chemical in Michigan, Martin Marietta Magnesia Specialties, and Rohm & Haas recovered dead-burned and caustic-calcined magnesias from seawater. And Premier Services' recoveries, in Nevada, were from magnasite.

  17. Polarity of oxide surfaces and nanostructures

    NASA Astrophysics Data System (ADS)

    Goniakowski, Jacek; Finocchi, Fabio; Noguera, Claudine

    2008-01-01

    Whenever a compound crystal is cut normal to a randomly chosen direction, there is an overwhelming probability that the resulting surface corresponds to a polar termination and is highly unstable. Indeed, polar oxide surfaces are subject to complex stabilization processes that ultimately determine their physical and chemical properties. However, owing to recent advances in their preparation under controlled conditions and to improvements in the experimental techniques for their characterization, an impressive variety of structures have been investigated in the last few years. Recent progress in the fabrication of oxide nano-objects, which have been largely stimulated by a growing demand for new materials for applications ranging from micro-electronics to heterogeneous catalysis, also offer interesting examples of exotic polar structures. At odds with polar orientations of macroscopic samples, some smaller size polar nano-structures turn out to be perfectly stable. Others are subject to unusual processes of stabilization, which are absent or not effective in their extended counterparts. In this context, a thorough and comprehensive reflexion on the role that polarity plays at oxide surfaces, interfaces and in nano-objects seems timely. This review includes a first section which presents the theoretical concepts at the root of the polar electrostatic instability and its compensation and introduces a rigorous definition of polar terminations that encompasses previous theoretical treatments; a second section devoted to a summary of all experimental and theoretical results obtained since the first review paper by Noguera (2000 J. Phys.: Condens. Matter 12 R367); and finally a discussion section focusing on the relative strength of the stabilization mechanisms, with special emphasis on ternary compound surfaces and on polarity effects in ultra-thin films.

  18. Engineering robust polar chiral clathrate crystals.

    PubMed

    Frampton, Christopher S; Ketuly, Kamal A; Hadi, A Hamid A; Gall, James H; Macnicol, David D

    2013-08-21

    The R-(+)-enantiomeric form of Dianin's compound and the S-(+)-enantiomeric form of its direct thiachroman analogue both obtained chromatographically employing a cellulose tris(3,5-dimethylphenylcarbamate) column, are shown to undergo supramolecular assembly to form a polar clathrate lattice which is stable even in the absence of a consolidating guest component. PMID:23799369

  19. Temperature- and frequency-dependent dielectric properties of organic–inorganic hybrid compound: (C{sub 6}H{sub 9}N{sub 2}){sub 2}(Hg{sub 0.75}Cd{sub 0.25})Cl{sub 4}

    SciTech Connect

    Elwej, R. Hamdi, M.; Hannachi, N.; Hlel, F.

    2015-02-15

    Highlights: • We have synthesized a new hybrid compound of composition (C6H9N2)2(Hg0.75Cd0.25)Cl4. • The Ac conductivity of the title material was studied as a function of frequency and temperature. • The dielectric data have been analyzed in modulus formalism using KWW. - Abstract: The bis-2-amino-4-picolinium tetrachloromercurate-cadmate compound (C{sub 6}H{sub 9}N{sub 2}){sub 2}(Hg{sub 0.75}Cd{sub 0.25})Cl{sub 4} was prepared by hydrothermal method and characterized by X-ray diffraction (XRD) technique. The electrical properties of the compound were studied using impedance spectroscopy in the frequency and temperature range of 200 Hz–5 MHz and 308–403 K, respectively. The equivalent circuit is modeled by a combination of a parallel Rp//CPE circuit to explain the impedance results. The dielectric data were analyzed using complex electrical modulus M* at various temperatures. The activation energy responsible for the relaxation calculated from the modulus spectra is found to be almost the same as the value obtained from the temperature variation of dc conductivity. The electrical modulus and its scaling behavior are also investigated.

  20. Jupiter: Aerosol Chemistry in the Polar Atmosphere.

    PubMed

    Wong; Lee; Yung; Ajello

    2000-05-10

    Aromatic compounds have been considered a likely candidate for enhanced aerosol formation in the polar region of Jupiter. We develop a new chemical model for aromatic compounds in the Jovian auroral thermosphere/ionosphere. The model is based on a previous model for hydrocarbon chemistry in the Jovian atmosphere and is constrained by observations from Voyager, Galileo, and the Infrared Space Observatory. Precipitation of energetic electrons provides the major energy source for the production of benzene and other heavier aromatic hydrocarbons. The maximum mixing ratio of benzene in the polar model is 2x10-9, a value that can be compared with the observed value of 2+2-1x10-9 in the north polar auroral region. Sufficient quantities of the higher ring species are produced so that their saturated vapor pressures are exceeded. Condensation of these molecules is expected to lead to aerosol formation. PMID:10813686

  1. Intercalated hybrid graphite fiber composite

    NASA Technical Reports Server (NTRS)

    Gaier, James R. (Inventor)

    1993-01-01

    The invention is directed to a highly conductive lightweight hybrid material and methods of producing the same. The hybrid composite is obtained by weaving strands of a high strength carbon or graphite fiber into a fabric-like structure, depositing a layer of carbon onto the structure, heat treating the structure to graphitize the carbon layer, and intercalating the graphitic carbon layer structure. A laminate composite material useful for protection against lightning strikes comprises at least one layer of the hybrid material over at least one layer of high strength carbon or graphite fibers. The composite material of the present invention is compatible with matrix compounds, has a coefficient of thermal expansion which is the same as underlying fiber layers, and is resistant to galvanic corrosion in addition to being highly conductive. These materials are useful in the aerospace industry, in particular as lightning strike protection for airplanes.

  2. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2003-01-01

    Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

  3. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  4. Ricean Bias Correction in Linear Polarization Observation

    NASA Astrophysics Data System (ADS)

    Sohn, Bong Won

    2011-12-01

    I developed an enhanced correction method for Ricean bias which occurs in linear polarization measurement. Two known methods for Ricean bias correction are reviewed. In low signal-to-noise area, the method based on the mode of the equation gives better representation of the fractional polarization. But a caution should be given that the accurate estimation of noise level, i.e. σ of the polarized flux, is important. The maximum likelihood method is better choice for high signal-to-noise area. I suggest a hybrid method which uses the mode of the equation at the low signal-to-noise area and takes the maximum likelihood method at the high signal-to-noise area. A modified correction coefficient for the mode solution is proposed. The impact on the depolarization measure analysis is discussed.

  5. Linearly polarized single TM mode terahertz waveguide.

    PubMed

    Li, Haisu; Ren, Guobin; Atakaramians, Shaghik; Kuhlmey, Boris T; Jian, Shuisheng

    2016-09-01

    We design a hollow-core terahertz (THz) waveguide guiding a single linearly polarized mode. This is achieved using a hybrid cladding, where we introduce a ring of subwavelength structures, including metal wires and air-holes. The wire-based cladding is extremely anisotropic, reflecting only transverse magnetic (TM) modes. The polarization of TM modes is further manipulated by replacing some wires with air-holes. Numerical simulations confirm the guidance of only an x-polarized TM2 mode over 0.36-0.46 THz in a wavelength-scale core (diameter of 1 mm). The propagation losses are of the order 0.25  dB/cm, with low bend losses <0.3  dB/cm at 0.4 THz for a bend radius of 5 cm. PMID:27607958

  6. Hybrid microelectronic technology

    NASA Astrophysics Data System (ADS)

    Moran, P.

    Various areas of hybrid microelectronic technology are discussed. The topics addressed include: basic thick film processing, thick film pastes and substrates, add-on components and attachment methods, thin film processing, and design of thick film hybrid circuits. Also considered are: packaging hybrid circuits, automating the production of hybrid circuits, application of hybrid techniques, customer's view of hybrid technology, and quality control and assurance in hybrid circuit production.

  7. Polarized Light Corridor Demonstrations.

    ERIC Educational Resources Information Center

    Davies, G. R.

    1990-01-01

    Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

  8. Polarization at SLAC

    SciTech Connect

    Woods, M.

    1995-01-01

    A highly polarized electron beam is a key feature. for the Current physics program at SLAC. An electron beam polarization of 80% can now be routinely achieved for typically 5000 hours of machine operation per year. Two main Physics programs utilize the polarized beam. Fixed target experiments in End Station A study the collision of polarized electrons with polarized nuclear targets to elucidate the spin structure of the nucleon and to provide an important test of QCD. Using the SLAC Linear Collider, collisions of polarized electrons with unpolarized positrons allow precise measurements of parity violation in the Z-fermion couplings and provide a very precise measurement of tile weak mixing angle. This paper discusses polarized beam operation at SLAC, and gives an overview of the polarized physics program.

  9. A Translational Polarization Rotator

    NASA Technical Reports Server (NTRS)

    Chuss, David T.; Wollack, Edward J.; Pisano, Giampaolo; Ackiss, Sheridan; U-Yen, Kongpop; Ng, Ming wah

    2012-01-01

    We explore a free-space polarization modulator in which a variable phase introduction between right- and left-handed circular polarization components is used to rotate the linear polarization of the outgoing beam relative to that of the incoming beam. In this device, the polarization states are separated by a circular polarizer that consists of a quarter-wave plate in combination with a wire grid. A movable mirror is positioned behind and parallel to the circular polarizer. As the polarizer-mirror distance is separated, an incident liear polarization will be rotated through an angle that is proportional to the introduced phase delay. We demonstrate a prototype device that modulates Stokes Q and U over a 20% bandwidth.

  10. High circular polarization in electroluminescence from MoSe2

    NASA Astrophysics Data System (ADS)

    Onga, Masaru; Zhang, Yijin; Suzuki, Ryuji; Iwasa, Yoshihiro

    2016-02-01

    The coupling between the valley degree of freedom and the optical helicity is one of the unique phenomena in transition metal dichalcogenides. The significant valley polarization evaluated from circularly polarized photoluminescence (PL) has been reported in many transition metal dichalcogenides, except in MoSe2. This compound is an anomalous material showing ultra-fast relaxation of the valley polarized states, which causes negligible polarization in the PL. Meanwhile, circularly polarized electroluminescence (EL) has been recently reported in a WSe2 light-emitting transistor, providing another method for using the valley degree of freedom. Here, we report the EL properties of MoSe2, demonstrating electrical switching of the optical helicity. Importantly, we observed high circular polarization reaching 66%. The results imply that the dominant mechanism of circularly polarized EL is robust against intervalley scattering, in marked contrast to the PL.

  11. Polar Ozone Workshop. Abstracts

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1988-01-01

    Results of the proceedings of the Polar Ozone Workshop held in Snowmass, CO, on May 9 to 13, 1988 are given. Topics covered include ozone depletion, ozonometry, polar meteorology, polar stratospheric clouds, remote sensing of trace gases, atmospheric chemistry and dynamical simulations.

  12. Graphing Polar Curves

    ERIC Educational Resources Information Center

    Lawes, Jonathan F.

    2013-01-01

    Graphing polar curves typically involves a combination of three traditional techniques, all of which can be time-consuming and tedious. However, an alternative method--graphing the polar function on a rectangular plane--simplifies graphing, increases student understanding of the polar coordinate system, and reinforces graphing techniques learned…

  13. Playing with Polarizers.

    ERIC Educational Resources Information Center

    Hecht, Jeff

    1991-01-01

    Discussed is how polarized sunglasses block glare, help spot subtle differences in surfaces, and give a clearer view under water. Information on unpolarized and polarized light is provided. The reasons causing glare to occur and how polarizers decrease glare are discussed. (KR)

  14. Polarity at Many Levels

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    2004-01-01

    An attempt is made to find how polarity arises and is maintained, which is a central issue in development. It is a fundamental attribute of living things and cellular polarity is also important in the development of multicellular organisms and controversial new work indicates that polarization in mammals may occur much earlier than previously…

  15. Physics with Polarized Nuclei.

    ERIC Educational Resources Information Center

    Thompson, William J.; Clegg, Thomas B.

    1979-01-01

    Discusses recent advances in polarization techniques, specifically those dealing with polarization of atomic nuclei, and how polarized beams and targets are produced. These techniques have greatly increased the scope of possible studies, and provided the tools for testing fundamental symmetries and the spin dependence of nuclear forces. (GA)

  16. Bumblebees Learn Polarization Patterns

    PubMed Central

    Foster, James J.; Sharkey, Camilla R.; Gaworska, Alicia V.A.; Roberts, Nicholas W.; Whitney, Heather M.; Partridge, Julian C.

    2014-01-01

    Summary Foraging insect pollinators such as bees must find and identify flowers in a complex visual environment. Bees use skylight polarization patterns for navigation [1–3], a capacity mediated by the polarization-sensitive dorsal rim area (DRA) of their eye [4, 5]. While other insects use polarization sensitivity to identify appropriate habitats [6], oviposition sites, and food sources [7], to date no nonnavigational functions of polarization vision have been identified in bees. Here we investigated the ability of bumblebees (Bombus terrestris) to learn polarization patterns on artificial “flowers” in order to obtain a food reward. We show that foraging bumblebees can learn to discriminate between two differently polarized targets, but only when the target artificial “flower” is viewed from below. A context for these results is provided by polarization imaging of bee-pollinated flowers, revealing the potential for polarization patterns in real flowers. Bees may therefore have the ability to use polarization vision, possibly mediated by their polarization-sensitive DRA, both for navigation and to learn polarization patterns on flowers, the latter being the first nonnavigational function for bee polarization vision to be identified. PMID:24909321

  17. Polarization feedback laser stabilization

    DOEpatents

    Esherick, Peter; Owyoung, Adelbert

    1988-01-01

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other.

  18. Calculation of polarization effects

    SciTech Connect

    Chao, A.W.

    1983-09-01

    Basically there are two areas of accelerator applications that involve beam polarization. One is the acceleration of a polarized beam (most likely a proton beam) in a synchrotron. Another concerns polarized beams in an electron storage ring. In both areas, numerical techniques have been very useful.

  19. Quantum mechanical force field for water with explicit electronic polarization

    SciTech Connect

    Han, Jaebeom; Mazack, Michael J. M.; Zhang, Peng; Truhlar, Donald G.; Gao, Jiali

    2013-08-07

    A quantum mechanical force field (QMFF) for water is described. Unlike traditional approaches that use quantum mechanical results and experimental data to parameterize empirical potential energy functions, the present QMFF uses a quantum mechanical framework to represent intramolecular and intermolecular interactions in an entire condensed-phase system. In particular, the internal energy terms used in molecular mechanics are replaced by a quantum mechanical formalism that naturally includes electronic polarization due to intermolecular interactions and its effects on the force constants of the intramolecular force field. As a quantum mechanical force field, both intermolecular interactions and the Hamiltonian describing the individual molecular fragments can be parameterized to strive for accuracy and computational efficiency. In this work, we introduce a polarizable molecular orbital model Hamiltonian for water and for oxygen- and hydrogen-containing compounds, whereas the electrostatic potential responsible for intermolecular interactions in the liquid and in solution is modeled by a three-point charge representation that realistically reproduces the total molecular dipole moment and the local hybridization contributions. The present QMFF for water, which is called the XP3P (explicit polarization with three-point-charge potential) model, is suitable for modeling both gas-phase clusters and liquid water. The paper demonstrates the performance of the XP3P model for water and proton clusters and the properties of the pure liquid from about 900 × 10{sup 6} self-consistent-field calculations on a periodic system consisting of 267 water molecules. The unusual dipole derivative behavior of water, which is incorrectly modeled in molecular mechanics, is naturally reproduced as a result of an electronic structural treatment of chemical bonding by XP3P. We anticipate that the XP3P model will be useful for studying proton transport in solution and solid phases as well as

  20. Quantum mechanical force field for water with explicit electronic polarization

    PubMed Central

    Han, Jaebeom; Mazack, Michael J. M.; Zhang, Peng; Truhlar, Donald G.; Gao, Jiali

    2013-01-01

    A quantum mechanical force field (QMFF) for water is described. Unlike traditional approaches that use quantum mechanical results and experimental data to parameterize empirical potential energy functions, the present QMFF uses a quantum mechanical framework to represent intramolecular and intermolecular interactions in an entire condensed-phase system. In particular, the internal energy terms used in molecular mechanics are replaced by a quantum mechanical formalism that naturally includes electronic polarization due to intermolecular interactions and its effects on the force constants of the intramolecular force field. As a quantum mechanical force field, both intermolecular interactions and the Hamiltonian describing the individual molecular fragments can be parameterized to strive for accuracy and computational efficiency. In this work, we introduce a polarizable molecular orbital model Hamiltonian for water and for oxygen- and hydrogen-containing compounds, whereas the electrostatic potential responsible for intermolecular interactions in the liquid and in solution is modeled by a three-point charge representation that realistically reproduces the total molecular dipole moment and the local hybridization contributions. The present QMFF for water, which is called the XP3P (explicit polarization with three-point-charge potential) model, is suitable for modeling both gas-phase clusters and liquid water. The paper demonstrates the performance of the XP3P model for water and proton clusters and the properties of the pure liquid from about 900 × 106 self-consistent-field calculations on a periodic system consisting of 267 water molecules. The unusual dipole derivative behavior of water, which is incorrectly modeled in molecular mechanics, is naturally reproduced as a result of an electronic structural treatment of chemical bonding by XP3P. We anticipate that the XP3P model will be useful for studying proton transport in solution and solid phases as well as across

  1. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2010-01-01

    Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

  2. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2002-01-01

    Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  3. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2011-01-01

    Seawater and natural brines accounted for about 54 percent of U.S. magnesium compounds production in 2010. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash-Wendover and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its operation mentioned above.

  4. Is CH3NH3PbI3 Polar?

    PubMed

    G, Sharada; Mahale, Pratibha; Kore, Bhushan P; Mukherjee, Somdutta; Pavan, Mysore S; De, Chandan; Ghara, Somnath; Sundaresan, A; Pandey, Anshu; Guru Row, Tayur N; Sarma, D D

    2016-07-01

    In view of the continued controversy concerning the polar/nonpolar nature of the hybrid perovskite system, CH3NH3PbI3, we report the first investigation of a time-resolved pump-probe measurement of the second harmonic generation efficiency as well as using its more traditional form as a sensitive probe of the absence/presence of the center of inversion in the system both in its excited and ground states, respectively. Our results clearly show that SHG efficiency, if nonzero, is below the limit of detection, strongly indicative of a nonpolar or centrosymmetric structure. Our results on the same samples, based on temperature dependent single crystal X-ray diffraction and P-E loop measurements, are entirely consistent with the above conclusion of a centrosymmetric structure for this compound in all three phases, namely the high temperature cubic phase, the intermediate temperature tetragonal phase and the low temperature orthorhombic phase. It is important to note that all our experimental probes are volume averaging and performed on bulk materials, suggesting that basic material properties of CH3NH3PbI3 are consistent with a centrosymmetric, nonpolar structure. PMID:27282976

  5. Superconducting-semiconducting nanowire hybrid microwave circuits

    NASA Astrophysics Data System (ADS)

    de Lange, G.; van Heck, B.; Bruno, A.; van Woerkom, D.; Geresdi, A.; Plissard, S. R.; Bakkers, E. P. A. M.; Akhmerov, A. R.; Dicarlo, L.

    2015-03-01

    Hybrid superconducting-semiconducting circuits offer a versatile platform for studying quantum effects in mesoscopic solid-state systems. We report the realization of hybrid artificial atoms based on Indium-Arsenide nanowire Josephson elements in a circuit quantum electrodynamics architecture. Transmon-like single-junction devices have gate-tunable transition frequencies. Split-junction devices behave as transmons near zero applied flux and as flux qubits near half flux quantum, wherein states with oppositely flowing persistent current can be driven by microwaves. This flux-qubit like behaviour results from non-sinusoidal current-phase relations in the nanowire Josephson elements. These hybrid microwave circuits are made entirely of magnetic-field compatible materials, offering new opportunities for hybrid experiments combining microwave circuits with polarized spin ensembles and Majorana bound states. We acknowledge funding from Microsoft Research and the Dutch Organization for Fundamental Research on Matter (FOM).

  6. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

  7. Intermetallic Compounds

    NASA Astrophysics Data System (ADS)

    Takagiwa, Y.; Matsuura, Y.; Kimura, K.

    2014-06-01

    We have focused on the binary narrow-bandgap intermetallic compounds FeGa3 and RuGa3 as thermoelectric materials. Their crystal structure is FeGa3-type (tetragonal, P42/ mnm) with 16 atoms per unit cell. Despite their simple crystal structure, their room temperature thermal conductivity is in the range 4-5-W-m-1-K-1. Both compounds have narrow-bandgaps of approximately 0.3-eV near the Fermi level. Because their Seebeck coefficients are quite large negative values in the range 350-<-| S 373K|-<-550- μV-K-1 for undoped samples, it should be possible to obtain highly efficient thermoelectric materials both by adjusting the carrier concentration and by reducing the thermal conductivity. Here, we report the effects of doping on the thermoelectric properties of FeGa3 and RuGa3 as n and p-type materials. The dimensionless figure of merit, ZT, was significantly improved by substitution of Sn for Ga in FeGa3 (electron-doping) and by substitution of Zn for Ga in RuGa3 (hole-doping), mainly as a result of optimization of the electronic part, S 2 σ.

  8. Linearly polarized light emission from quantum dots with plasmonic nanoantenna arrays.

    PubMed

    Ren, Mengxin; Chen, Mo; Wu, Wei; Zhang, Lihui; Liu, Junku; Pi, Biao; Zhang, Xinzheng; Li, Qunqing; Fan, Shoushan; Xu, Jingjun

    2015-05-13

    Polarizers provide convenience in generating polarized light, meanwhile their adoption raises problems of extra weight, cost, and energy loss. Aiming to realize polarizer-free polarized light sources, herein, we present a plasmonic approach to achieve direct generation of linearly polarized optical waves at the nanometer scale. Periodic slot nanoantenna arrays are fabricated, which are driven by the transition dipole moments of luminescent semiconductor quantum dots. By harnessing interactions between quantum dots and scattered fields from the nanoantennas, spontaneous emission with a high degree of linear polarization is achieved from such hybrid antenna system with polarization perpendicular to antenna slot. We also demonstrate that the polarization is engineerable in aspects of both spectrum and magnitude by tailoring plasmonic resonance of the antenna arrays. Our findings will establish a basis for the development of innovative polarized light-emitting devices, which are useful in optical displays, spectroscopic techniques, optical telecommunications, and so forth. PMID:25877386

  9. Hybrid Gear

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  10. Thermally activated delayed fluorescence with circularly polarized luminescence characteristics.

    PubMed

    Imagawa, Takuro; Hirata, Shuzo; Totani, Kenro; Watanabe, Toshiyuki; Vacha, Martin

    2015-09-01

    A metal-free aromatic compound with a chiral carbon sandwiched between a donor moiety and an acceptor moiety was designed. Under thermally activated delayed fluorescence, the compound displayed a photoluminescence quantum yield of 26%, and showed circularly polarized luminescence with a dissymmetry factor of 10(-3). PMID:26207648

  11. Composition law for polarizers

    NASA Astrophysics Data System (ADS)

    Lages, J.; Giust, R.; Vigoureux, J.-M.

    2008-09-01

    The polarization process when polarizers act on an optical field is studied. We give examples for two kinds of polarizers. The first kind presents an anisotropic absorption—as in a Polaroid film—and the second one is based on total reflection at the interface with a birefringent medium. Using the Stokes vector representation, we determine explicitly the trajectories of the wave light polarization during the polarization process. We find that such trajectories are not always geodesics of the Poincaré sphere as is usually thought. Using the analogy between light polarization and special relativity, we find that the action of successive polarizers on the light wave polarization is equivalent to the action of a single resulting polarizer followed by a rotation achieved, for example, by a device with optical activity. We find a composition law for polarizers similar to the composition law for noncollinear velocities in special relativity. We define an angle equivalent to the relativistic Wigner angle which can be used to quantify the quality of two composed polarizers.

  12. The Physics of Polarization

    NASA Astrophysics Data System (ADS)

    Degl'Innocenti, Egidio Landi

    2015-10-01

    The introductory lecture that has been delivered at this Symposium is a condensed version of an extended course held by the author at the XII Canary Island Winter School from November 13 to November 21, 2000. The full series of lectures can be found in Landi Degl'Innocenti (2002). The original reference is organized in 20 Sections that are here itemized: 1. Introduction, 2. Description of polarized radiation, 3. Polarization and optical devices: Jones calculus and Muller matrices, 4. The Fresnel equations, 5. Dichroism and anomalous dispersion, 6. Polarization in everyday life, 7. Polarization due to radiating charges, 8. The linear antenna, 9. Thomson scattering, 10. Rayleigh scattering, 11. A digression on Mie scattering, 12. Bremsstrahlung radiation, 13. Cyclotron radiation, 14. Synchrotron radiation, 15. Polarization in spectral lines, 16. Density matrix and atomic polarization, 17. Radiative transfer and statistical equilibrium equations, 18. The amplification condition in polarized radiative transfer, and 19. Coupling radiative transfer and statistical equilibrium equations.

  13. Treatment System for Removing Halogenated Compounds from Contaminated Sources

    NASA Technical Reports Server (NTRS)

    Quinn, Jacqueline W. (Inventor); Clausen, Christian A. (Inventor); Yestrebsky, Cherie L. (Inventor)

    2015-01-01

    A treatment system and a method for removal of at least one halogenated compound, such as PCBs, found in contaminated systems are provided. The treatment system includes a polymer blanket for receiving at least one non-polar solvent. The halogenated compound permeates into or through a wall of the polymer blanket where it is solubilized with at least one non-polar solvent received by said polymer blanket forming a halogenated solvent mixture. This treatment system and method provides for the in situ removal of halogenated compounds from the contaminated system. In one embodiment, the halogenated solvent mixture is subjected to subsequent processes which destroy and/or degrade the halogenated compound.

  14. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2012-01-01

    Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.

  15. Bismaleimide compounds

    DOEpatents

    Adams, Johnnie E.; Jamieson, Donald R.

    1986-01-14

    Bismaleimides of the formula ##STR1## wherein R.sub.1 and R.sub.2 each independently is H, C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, C1 or Br, or R.sub.1 and R.sub.2 together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R.sub.1 and R.sub.2 are not t-butyl or t-butoxy; X is O, S or Se; n is 1-3; and the alkylene bridging group, optionally, is substituted by 1-3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

  16. Bismaleimide compounds

    DOEpatents

    Adams, J.E.; Jamieson, D.R.

    1986-01-14

    Bismaleimides of the formula shown in the diagram wherein R[sub 1] and R[sub 2] each independently is H, C[sub 1-4]-alkyl, C[sub 1-4]-alkoxy, Cl or Br, or R[sub 1] and R[sub 2] together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R[sub 1] and R[sub 2] are not t-butyl or t-butoxy; X is O, S or Se; n is 1--3; and the alkylene bridging group, optionally, is substituted by 1--3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

  17. Process of forming compounds using reverse micelle or reverse microemulsion systems

    DOEpatents

    Linehan, John C.; Fulton, John L.; Bean, Roger M.

    1998-01-01

    The present invention is directed to a process for producing a nanometer-sized metal compound. The process comprises forming a reverse micelle or reverse microemulsion system comprising a polar fluid in a non-polar or low-polarity fluid. A first reactant comprising a multi-component, water-soluble metal compound is introduced into the polar fluid in a non-polar or low-polarity fluid. This first reactant can be introduced into the reverse micelle or reverse microemulsion system during formation thereof or subsequent to the formation of the reverse micelle or microemulsion system. The water-soluble metal compound is then reacted in the reverse micelle or reverse microemulsion system to form the nanometer-sized metal compound. The nanometer-sized metal compound is then precipitated from the reverse micelle or reverse microemulsion system.

  18. ) Hybrid Composite

    NASA Astrophysics Data System (ADS)

    Show, Bijay Kumar; Mondal, Dipak Kumar; Maity, Joydeep

    2014-12-01

    In this research work, the dry sliding wear behavior of 6351 Al-(4 vol.% SiC + 4 vol.% Al2O3) hybrid composite was investigated at low sliding speed (1 m/s) against a hardened EN 31 disk at different loads. In general, the wear mechanism involved adhesion (along with associated subsurface cracking and delamination) and microcutting abrasion at lower load. While at higher load, abrasive wear involving microcutting and microploughing along with adherent oxide formation was observed. The overall wear rate increased with increasing normal load. The massive particle clusters as well as individual reinforcement particles were found to stand tall to resist abrasive wear. Besides, at higher load, the generation of adherent nodular tribo-oxide through nucleation and epitaxial growth on existing Al2O3 particles lowered down the wear rate. Accordingly, at any normal load, 6351 Al-(4 vol.% SiC + 4 vol.% Al2O3) hybrid composite exhibited superior wear resistance (lower overall wear rate) than the reported wear resistance of monolithic 6351 Al alloy.

  19. Hybrid Simulator

    Energy Science and Technology Software Center (ESTSC)

    2005-10-15

    HybSim (short for Hybrid Simulator) is a flexible, easy to use screening tool that allows the user to quanti the technical and economic benefits of installing a village hybrid generating system and simulates systems with any combination of —Diesel generator sets —Photovoltaic arrays -Wind Turbines and -Battery energy storage systems Most village systems (or small population sites such as villages, remote military bases, small communities, independent or isolated buildings or centers) depend on diesel generationmore » systems for their source of energy. HybSim allows the user to determine other "sources" of energy that can greatly reduce the dollar to kilo-watt hour ratio. Supported by the DOE, Energy Storage Program, HybSim was initially developed to help analyze the benefits of energy storage systems in Alaskan villages. Soon after its development, other sources of energy were added providing the user with a greater range of analysis opportunities and providing the village with potentially added savings. In addition to village systems, HybSim has generated interest for use from military institutions in energy provisions and USAID for international village analysis.« less

  20. Device For Viewing Polarized Light

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    1995-01-01

    Technique for detection of polarized light based on observation of scene through two stacked polarizing disks. No need to rotate polarizers to create flicker indicative of polarization. Implemented by relatively simple, lightweight apparatus. Polarization seen as bow-tie rainbow pattern. Advantageous for detecting polarization in variety of meteorological, geological, astronomical, and related applications.

  1. Distribution of aroma volatiles in a population of tangerine hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    While orange juice volatile composition has been well studied, little is known about volatiles in tangerines. This study was undertaken to determine the most common compounds present in 45 tangerine hybrids, and to find relationships among these hybrids based on volatile content. Fruits were harve...

  2. Synthesis, SAR and antibacterial studies on novel chalcone oxazolidinone hybrids.

    PubMed

    Selvakumar, N; Kumar, G Sunil; Azhagan, A Malar; Rajulu, G Govinda; Sharma, Shikha; Kumar, M Sitaram; Das, Jagattaran; Iqbal, Javed; Trehan, Sanjay

    2007-04-01

    With an intention to synergise the antibacterial activity of chalcones and oxazolidinones, several hybrid compounds possessing both chalcone and oxazolidinone moieties were synthesized and tested for antibacterial activity. The hybrid molecules containing heterocycles instead of aromatic ring were found to be active. A SAR study with various heterocycles resulted in a lead molecule 20, which was converted to one of the potent antibacterial compounds 27. PMID:17150281

  3. Consecutive polarizers arrangement producing maximum polarized light intensity

    NASA Astrophysics Data System (ADS)

    Wirjawan, Johannes V. D.

    2016-03-01

    Polarizer mainly functions as a specific filter that blocks or transmits lights of certain polarization. Malus' law predicts the average intensity of polarized light passing a polarizer that transmits certain polarization direction will be proportional to the squared cosine of angle between the two polarization directions. Arranging several polarizers consecutively with various transmission directions will produce various final intensity as well as final polarized direction. Specific arrangement of an arbitrary number (N > 3) of polarizers producing maximum intensity of polarized light will be discussed in this paper. In addition, interesting pattern of maximum values of some trigonometric functions that are difficult to be solved analytically can be obtained from this discussion.

  4. Hybrid germanium iodide perovskite semiconductors: active lone pairs, structural distortions, direct and indirect energy gaps, and strong nonlinear optical properties.

    PubMed

    Stoumpos, Constantinos C; Frazer, Laszlo; Clark, Daniel J; Kim, Yong Soo; Rhim, Sonny H; Freeman, Arthur J; Ketterson, John B; Jang, Joon I; Kanatzidis, Mercouri G

    2015-06-01

    The synthesis and properties of the hybrid organic/inorganic germanium perovskite compounds, AGeI3, are reported (A = Cs, organic cation). The systematic study of this reaction system led to the isolation of 6 new hybrid semiconductors. Using CsGeI3 (1) as the prototype compound, we have prepared methylammonium, CH3NH3GeI3 (2), formamidinium, HC(NH2)2GeI3 (3), acetamidinium, CH3C(NH2)2GeI3 (4), guanidinium, C(NH2)3GeI3 (5), trimethylammonium, (CH3)3NHGeI3 (6), and isopropylammonium, (CH3)2C(H)NH3GeI3 (7) analogues. The crystal structures of the compounds are classified based on their dimensionality with 1–4 forming 3D perovskite frameworks and 5–7 1D infinite chains. Compounds 1–7, with the exception of compounds 5 (centrosymmetric) and 7 (nonpolar acentric), crystallize in polar space groups. The 3D compounds have direct band gaps of 1.6 eV (1), 1.9 eV (2), 2.2 eV (3), and 2.5 eV (4), while the 1D compounds have indirect band gaps of 2.7 eV (5), 2.5 eV (6), and 2.8 eV (7). Herein, we report on the second harmonic generation (SHG) properties of the compounds, which display remarkably strong, type I phase-matchable SHG response with high laser-induced damage thresholds (up to ∼3 GW/cm(2)). The second-order nonlinear susceptibility, χS(2), was determined to be 125.3 ± 10.5 pm/V (1), (161.0 ± 14.5) pm/V (2), 143.0 ± 13.5 pm/V (3), and 57.2 ± 5.5 pm/V (4). First-principles density functional theory electronic structure calculations indicate that the large SHG response is attributed to the high density of states in the valence band due to sp-hybridization of the Ge and I orbitals, a consequence of the lone pair activation. PMID:25950197

  5. Automatic Bayesian polarity determination

    NASA Astrophysics Data System (ADS)

    Pugh, D. J.; White, R. S.; Christie, P. A. F.

    2016-07-01

    The polarity of the first motion of a seismic signal from an earthquake is an important constraint in earthquake source inversion. Microseismic events often have low signal-to-noise ratios, which may lead to difficulties estimating the correct first-motion polarities of the arrivals. This paper describes a probabilistic approach to polarity picking that can be both automated and combined with manual picking. This approach includes a quantitative estimate of the uncertainty of the polarity, improving calculation of the polarity probability density function for source inversion. It is sufficiently fast to be incorporated into an automatic processing workflow. When used in source inversion, the results are consistent with those from manual observations. In some cases, they produce a clearer constraint on the range of high-probability source mechanisms, and are better constrained than source mechanisms determined using a uniform probability of an incorrect polarity pick.

  6. Automatic Bayesian polarity determination

    NASA Astrophysics Data System (ADS)

    Pugh, D. J.; White, R. S.; Christie, P. A. F.

    2016-04-01

    The polarity of the first motion of a seismic signal from an earthquake is an important constraint in earthquake source inversion. Microseismic events often have low signal-to-noise ratios, which may lead to difficulties estimating the correct first-motion polarities of the arrivals. This paper describes a probabilistic approach to polarity picking that can be both automated and combined with manual picking. This approach includes a quantitative estimate of the uncertainty of the polarity, improving calculation of the polarity probability density function for source inversion. It is sufficiently fast to be incorporated into an automatic processing workflow. When used in source inversion, the results are consistent with those from manual observations. In some cases, they produce a clearer constraint on the range of high-probability source mechanims, and are better constrained than source mechanisms determined using a uniform probability of an incorrect polarity pick.

  7. Hybridized tetraquarks

    NASA Astrophysics Data System (ADS)

    Esposito, A.; Pilloni, A.; Polosa, A. D.

    2016-07-01

    We propose a new interpretation of the neutral and charged X , Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules but rather a manifestation of the interplay between the two. While meson molecules need a negative or zero binding energy, its counterpart for h-tetraquarks is required to be positive. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs0 π± channel by the D0 Collaboration and the negative result presented subsequently by the LHCb Collaboration are understood in this scheme, together with a considerable portion of available data on X , Z particles. Considerations on a state with the same quantum numbers as the X (5568) are also made.

  8. Solid-state NMR characterization of the structure and thermal stability of hybrid organic-inorganic compounds based on a HLaNb2O7 Dion-Jacobson layered perovskite.

    PubMed

    Cattaneo, Alice S; Ferrara, Chiara; Marculescu, Adriana Mossuto; Giannici, Francesco; Martorana, Antonino; Mustarelli, Piercarlo; Tealdi, Cristina

    2016-08-01

    Dion-Jacobson phases, like MLaNb2O7, are an interesting class of ion-exchangeable layered perovskites possessing electronic and photocatalytic properties. Their protonated and organo-modified homologues, in particular, have already been indicated as promising catalysts. However, the structural analysis of these highly tailorable materials is still incomplete, and both the intercalation process and thermal stability of the included organic moieties are far from being completely understood. In this study, we present a thorough solid-state NMR characterization of HLaNb2O7·xH2O intercalated with different amounts of octylamine, or with decylamine. Samples were analyzed as prepared, and after thermal treatment at different temperatures up to 220 °C. The substitution of pristine proton ions was followed via(1)H MAS NMR spectroscopy, whereas the alkyl chains were monitored through (13)C((1)H) CP MAS experiments. The interactions in the interlayer space were explored using (13)C((1)H) 2D heteronuclear correlation experiments. We demonstrate that some of the protons are involved in the functionalization reaction, and some of them are in close proximity to the alkyl ammonium chains. Heating of the hybrid materials leads first to a rearrangement of the alkyl chains and then to their degradation. The spatial arrangement of the chains, their interactions and the thermal behavior of the materials depend on the extent of the functionalization, and on the nature of the intercalated alkyl ammonium ions. PMID:27440133

  9. A dual polarized antenna system using a meanderline polarizer

    NASA Technical Reports Server (NTRS)

    Burger, H. A.

    1978-01-01

    Certain applications of synthetic aperture radars require transmitting on one linear polarization and receiving on two orthogonal linear polarizations for adequate characterization of the surface. To meet the current need at minimum cost, it was desirable to use two identical horizontally polarized shaped beam antennas and to change the polarization of one of them by a polarization conversion plate. The plate was realized as a four-layer meanderline polarizer designed to convert horizontal polarization to vertical.

  10. Polarization feedback laser stabilization

    DOEpatents

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  11. Polar and Magneto-Electric Properties of Anti-Ferrodistortive Ordered Jahn-Teller Distortions in a multiferroic metal-organic framework

    NASA Astrophysics Data System (ADS)

    Stroppa, Alessandro

    2013-04-01

    There is great interest in hybrid organic-inorganic materials such as metal-organic frameworks (MOFs). Here, we focus on [C(NH2)3]Cu(HCOO)3, a MOF with perovskite topology which crystallizes in polar space group Pna21. In inorganic compounds, octahedral tilting and Jahn-Teller structural distortions are usually non-polar distortions. However, in this MOF cooperative interactions between the antiferro-distortive distortions of the framework and the C(NH2)3 organic cation via hydrogen bonding breaks the inversion symmetry and induces a ferroelectric polarization. Our ab-initio study supports the picture of an orbital-order-induced ferroelectricity, a rare example of dipolar ordering caused by electronic degrees of freedom. Moreover, we show that the switching of polarization direction implies the reversal of the weak ferromagnetic component. These results therefore offer an important starting point for tailoring multiferroic properties in this emerging class of materials for various technological applications.

  12. Asymmetric chemical reactions by polarized quantum beams

    NASA Astrophysics Data System (ADS)

    Takahashi, Jun-Ichi; Kobayashi, Kensei

    One of the most attractive hypothesis for the origin of homochirality in terrestrial bio-organic compounds (L-amino acid and D-sugar dominant) is nominated as "Cosmic Scenario"; a chiral impulse from asymmetric excitation sources in space triggered asymmetric reactions on the surfaces of such space materials as meteorites or interstellar dusts prior to the existence of terrestrial life. 1) Effective asymmetric excitation sources in space are proposed as polarized quantum beams, such as circularly polarized light and spin polarized electrons. Circularly polarized light is emitted as synchrotron radiation from tightly captured electrons by intense magnetic field around neutron stars. In this case, either left-or right-handed polarized light can be observed depending on the direction of observation. On the other hand, spin polarized electrons is emitted as beta-ray in beta decay from radioactive nuclei or neutron fireballs in supernova explosion. 2) The spin of beta-ray electrons is longitudinally polarized due to parity non-conservation in the weak interaction. The helicity (the the projection of the spin onto the direction of kinetic momentum) of beta-ray electrons is universally negative (left-handed). For the purpose of verifying the asymmetric structure emergence in bio-organic compounds by polarized quantum beams, we are now carrying out laboratory simulations using circularly polarized light from synchrotron radiation facility or spin polarized electron beam from beta-ray radiation source. 3,4) The target samples are solid film or aqueous solution of racemic amino acids. 1) K.Kobayashi, K.Kaneko, J.Takahashi, Y.Takano, in Astrobiology: from simple molecules to primitive life; Ed. V.Basiuk; American Scientific Publisher: Valencia, 2008. 2) G.A.Gusev, T.Saito, V.A.Tsarev, A.V.Uryson, Origins Life Evol. Biosphere. 37, 259 (2007). 3) J.Takahashi, H.Shinojima, M.Seyama, Y.Ueno, T.Kaneko, K.Kobayashi, H.Mita, M.Adachi, M.Hosaka, M.Katoh, Int. J. Mol. Sci. 10, 3044

  13. Asymptotes in Polar Coordinates.

    ERIC Educational Resources Information Center

    Fay, Temple H.

    1986-01-01

    An old way to determine asymptotes for curves described in polar coordinates is presented. Practice in solving trigonometric equations, in differentiation, and in calculating limits is involved. (MNS)

  14. Polarization at SLC

    SciTech Connect

    Swartz, M.L.

    1988-07-01

    The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs.

  15. Polarized negative ions

    SciTech Connect

    Haeberli, W.

    1981-04-01

    This paper presents a survey of methods, commonly in use or under development, to produce beams of polarized negative ions for injection into accelerators. A short summary recalls how the hyperfine interaction is used to obtain nuclear polarization in beams of atoms. Atomic-beam sources for light ions are discussed. If the best presently known techniques are incorporated in all stages of the source, polarized H/sup -/ and D/sup -/ beams in excess of 10 ..mu..A can probably be achieved. Production of polarized ions from fast (keV) beams of polarized atoms is treated separately for atoms in the H(25) excited state (Lamb-Shift source) and atoms in the H(1S) ground state. The negative ion beam from Lamb-Shift sources has reached a plateau just above 1 ..mu..A, but this beam current is adequate for many applications and the somewhat lower beam current is compensated by other desirable characteristics. Sources using fast polarized ground state atoms are in a stage of intense development. The next sections summarize production of polarized heavy ions by the atomic beam method, which is well established, and by optical pumping, which has recently been demonstrated to yield very large nuclear polarization. A short discussion of proposed ion sources for polarized /sup 3/He/sup -/ ions is followed by some concluding remarks.

  16. Polarization In Remote Sensing

    NASA Astrophysics Data System (ADS)

    Egan, Walter G.

    1988-06-01

    Various aspects of polarization in remote sensing are presented including mathematical treatments and selected experimental observations. The observations are of the percent polarization from Haleakala volcanic ash, basalt powder, rhyolytic oumice. rose quartz, niccolite, ilmenite, black oak leaves. dried red pine needles, a New Haven red pine stand, moist soil, the sky above Mauna Loa Observatory, the sky above Long Island in summer and winter, and cirrus clouds. Also, space based shuttle photographic observations of polarization are described. Instrumental polarization from a Cassegrainian telescope is described as well as the design of an imaging soectropolarimeter for remote sensing. A list is presented of twelve polarimetric properties associated with remote sensing.

  17. Extraterrestrial Organic Compounds in Meteorites

    NASA Technical Reports Server (NTRS)

    Botta, Oliver; Bada, Jeffrey L.; Meyer, Michael (Technical Monitor)

    2003-01-01

    Many organic compounds or their precursors found in meteorites originated in the interstellar or circumstellar medium and were later incorporated into planetesimals during the formation of the solar system. There they either survived intact or underwent further processing to synthesize secondary products on the meteorite parent body. The most distinct feature of CI and CM carbonaceous chondrites, two types of stony meteorites, is their high carbon content (up to 3% of weight), either in the form of carbonates or of organic compounds. The bulk of the organic carbon consists of an insoluble macromolecular material with a complex structure. Also present is a soluble organic fraction, which has been analyzed by several separation and analytical procedures. Low detection limits can be achieved by derivatization of the organic molecules with reagents that allow for analysis by gas chromatography/mass spectroscopy and high performance liquid chromatography. The CM meteorite Murchison has been found to contain more than 70 extraterrestrial amino acids and several other classes of compounds including carboxylic acids, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbons, fullerenes, heterocycles as well as carbonyl compounds, alcohols, amines and amides. The organic matter was found to be enriched in deuterium, and distinct organic compounds show isotopic enrichments of carbon and nitrogen relative to terrestrial matter.

  18. Floral traits and pollination ecology of European Arum hybrids.

    PubMed

    Chartier, Marion; Liagre, Suzanne; Weiss-Schneeweiss, Hanna; Kolano, Bozena; Bessière, Jean-Marie; Schönenberger, Jürg; Gibernau, Marc

    2016-02-01

    Hybridisation is common in plants and can affect the genetic diversity and ecology of sympatric parental populations. Hybrids may resemble the parental species in their ecology, leading to competition and/or gene introgression; alternatively, they may diverge from the parental phenotypes, possibly leading to the colonisation of new ecological niches and to speciation. Here, we describe inflorescence morphology, ploidy levels, pollinator attractive scents, and pollinator guilds of natural hybrids of Arum italicum and A. maculatum (Araceae) from a site with sympatric parental populations in southern France to determine how these traits affect the hybrid pollination ecology. Hybrids were characterised by inflorescences with a size and a number of flowers more similar to A. italicum than to A. maculatum. In most cases, hybrid stamens were purple, as in A. maculatum, and spadix appendices yellow, as in A. italicum. Hybrid floral scent was closer to that of A. italicum, but shared some compounds with A. maculatum and comprised unique compounds. Also, the pollinator guild of the hybrids was similar to that of A. italicum. Nevertheless, the hybrids attracted a high proportion of individuals of the main pollinator of A. maculatum. We discuss the effects of hybridisation in sympatric parental zones in which hybrids exhibit low levels of reproductive success, the establishment of reproductive barriers between parental species, the role of the composition of floral attractive scents in the differential attraction of pollinators and in the competition between hybrids and their parental species, and the potential of hybridisation to give rise to new independent lineages. PMID:26552380

  19. Supramolecular hydrogen-bonding patterns in the organic-inorganic hybrid compound bis(4-amino-5-chloro-2,6-dimethylpyrimidinium) tetrathiocyanatozinc(II)-4-amino-5-chloro-2,6-dimethylpyrimidine-water (1/2/2).

    PubMed

    Karthikeyan, Ammasai; Zeller, Matthias; Thomas Muthiah, Packianathan

    2016-04-01

    Zinc thiocyanate complexes have been found to be biologically active compounds. Zinc is also an essential element for the normal function of most organisms and is the main constituent in a number of metalloenzyme proteins. Pyrimidine and aminopyrimidine derivatives are biologically very important as they are components of nucleic acids. Thiocyanate ions can bridge metal ions by employing both their N and S atoms for coordination. They can play an important role in assembling different coordination structures and yield an interesting variety of one-, two- and three-dimensional polymeric metal-thiocyanate supramolecular frameworks. The structure of a new zinc thiocyanate-aminopyrimidine organic-inorganic compound, (C6H9ClN3)2[Zn(NCS)4]·2C6H8ClN3·2H2O, is reported. The asymmetric unit consist of half a tetrathiocyanatozinc(II) dianion, an uncoordinated 4-amino-5-chloro-2,6-dimethylpyrimidinium cation, a 4-amino-5-chloro-2,6-dimethylpyrimidine molecule and a water molecule. The Zn(II) atom adopts a distorted tetrahedral coordination geometry and is coordinated by four N atoms from the thiocyanate anions. The Zn(II) atom is located on a special position (twofold axis of symmetry). The pyrimidinium cation and the pyrimidine molecule are not coordinated to the Zn(II) atom, but are hydrogen bonded to the uncoordinated water molecules and the metal-coordinated thiocyanate ligands. The pyrimidine molecules and pyrimidinium cations also form base-pair-like structures with an R2(2)(8) ring motif via N-H...N hydrogen bonds. The crystal structure is further stabilized by intermolecular N-H...O, O-H...S, N-H...S and O-H...N hydrogen bonds, by intramolecular N-H...Cl and C-H...Cl hydrogen bonds, and also by π-π stacking interactions. PMID:27045184

  20. Hybrid anode for semiconductor radiation detectors

    DOEpatents

    Yang, Ge; Bolotnikov, Aleksey E; Camarda, Guiseppe; Cui, Yonggang; Hossain, Anwar; Kim, Ki Hyun; James, Ralph B

    2013-11-19

    The present invention relates to a novel hybrid anode configuration for a radiation detector that effectively reduces the edge effect of surface defects on the internal electric field in compound semiconductor detectors by focusing the internal electric field of the detector and redirecting drifting carriers away from the side surfaces of the semiconductor toward the collection electrode(s).

  1. Lower hybrid emission diagnostics on the NASA Lewis bumpy torus

    NASA Technical Reports Server (NTRS)

    Mallavarpu, R.

    1977-01-01

    The feasibility of using RF emission near the lower hybrid frequency of the NASA Lewis Bumpy Torus plasma for diagnostic purposes is examined. The emission is detected using a spectrum analyzer and a 50 omega miniature coaxial antenna that is sensitive to the polarization of the incoming signal. The frequency shift of the lower hybrid emission peak is monitored as a function of the background pressure, electrode voltage, electrode ring configuration and the strength of the toroidal dc magnetic field. Simultaneous measurements of the average plasma density are made with a polarization diplexing microwave interferometer. Data derived from the experiment are discussed with reference to the following: (1) the strength of the dc magnetic field in the emitting region; (2) comparison of the lower hybrid plasma density with the average plasma density; and (3) validity of the cold plasma lower hybrid resonance formula in the high density operating regime of the bumpy torus plasma.

  2. Strongly hybridized plasmon-photon modes in optoplasmonic microtubular cavities

    NASA Astrophysics Data System (ADS)

    Yin, Y.; Li, S. L.; Giudicatti, S.; Jiang, C. Y.; Ma, L. B.; Schmidt, O. G.

    2015-12-01

    Strongly hybridized plasmon-photon modes are observed in a microtubular cavity coated with a gold nanocap. Polarization-resolved measurements reveal that the transverse magnetic polarized light predominantly excites the hybrid resonant modes in these optoplasmonic microcavities. Remarkably, the exterior field of the hybrid mode is enhanced by more than an order of magnitude over previously reported designs and is caused by the light confinement in an extremely thin cavity wall. Both finite element method calculations and an effective potential approach confirm our experimental observations. Our work reveals the basic physical mechanisms responsible for exciting hybrid modes in optoplasmonic microcavities and as such is relevant for both fundamental and applied studies in photonics and plasmonics.

  3. Macroscopic dynamics of polar nematic liquid crystals.

    PubMed

    Brand, Helmut R; Pleiner, Harald; Ziebert, Falko

    2006-08-01

    We present the macroscopic equations for polar nematic liquid crystals. We consider the case where one has both, the usual nematic director, n[over ] , characterizing quadrupolar order as well as the macroscopic polarization, P , representing polar order, but where their directions coincide and are rigidly coupled. In this case one has to choose P as the independent macroscopic variable. Such equations are expected to be relevant in connection with nematic phases with unusual properties found recently in compounds composed of banana-shaped molecules. Among the effects predicted, which are absent in conventional nematic liquid crystals showing only quadrupolar order, are pyro-electricity and its analogs for density and for concentration in mixtures as well as a flow alignment behavior, which is more complex than in usual low molecular weight nematics. We also discuss the formation of defect structures expected in such systems. PMID:17025458

  4. RHIC Polarized proton operation

    SciTech Connect

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D'Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R,; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; J.; Severino, F.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J. Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-03-28

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP{sup 4}. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above

  5. The Polar Insulation Investigation

    ERIC Educational Resources Information Center

    Urban-Rich, Juanita

    2006-01-01

    In this article, the author developed an activity called "The Polar Insulation Investigation." This activity builds on students' natural interest in "things polar" and introduces them to animal adaptations in a unique way. The aim of the exploration is to determine the role of animal coverings (e.g., blubber, fur, and feathers) and to see which is…

  6. Our Polar Past

    ERIC Educational Resources Information Center

    Clary, Renee; Wandersee, James

    2009-01-01

    The study of polar exploration is fascinating and offers students insights into the history, culture, and politics that affect the developing sciences at the farthest ends of Earth. Therefore, the authors think there is value in incorporating polar exploration accounts within modern science classrooms, and so they conducted research to test their…

  7. Polar Science Is Cool!

    ERIC Educational Resources Information Center

    Weeks, Sophie

    2012-01-01

    Children are fascinated by the fact that polar scientists do research in extremely cold and dangerous places. In the Arctic they might be viewed as lunch by a polar bear. In the Antarctic, they could lose toes and fingers to frostbite and the wind is so fast it can rip skin off. They camp on ice in continuous daylight, weeks from any form of…

  8. Polarized Light: Three Demonstrations.

    ERIC Educational Resources Information Center

    Goehmann, Ruth; Welty, Scott

    1984-01-01

    Describes three demonstrations used in the Chicago Museum of Science and Industry polarized light show. The procedures employed are suitable for the classroom by using smaller polarizers and an overhead projector. Topic areas include properties of cellophane tape, nondisappearing arrows, and rope through a picket fence. (JN)

  9. Mechanism of lunar polarization.

    PubMed

    Hopfield, J J

    1966-03-18

    A theoretical model to explain the negative polarization of moonlight at small lunar phase angles is developed. The model is based on the polarization of light in the diffraction region bordering the geometric shadow of an opaque dielectric obstacle. PMID:17817298

  10. Measurements of optical polarization properties in dental tissues and biomaterials

    NASA Astrophysics Data System (ADS)

    Fernández-Oliveras, Alicia; Pecho, Oscar E.; Rubiño, Manuel; Pérez, María M.

    2011-05-01

    Since biological tissues can have the intrinsic property of altering the polarization of incident light, optical polarization studies are important for a complete characterization. We have measured the polarized light scattered off of different dental tissues and biomaterials for a comparative study of their optical polarization property. The experimental setup was composed by a He-Ne laser, two linear polarizers and a detection system based on a photodiode. The laser beam was passed through one linear polarizer placed in front of the sample, beyond which the second linear polarizer (analyzer) and the photodiode detector were placed. First, the maximum laser-light intensity (reference condition) was attained without the sample in the laser path. Then, the sample was placed between the two polarizers and the polarization shift of the scattered laser light was determined by rotating the analyzer until the reference condition was reached. Two dental-resin composites (nanocomposite and hybrid) and two human dental tissues (enamel and dentine) were analyzed under repeatability conditions at three different locations on the sample: 20 measurements of the shift were taken and the average value and the uncertainty associated were calculated. For the human dentine the average value of the polarization shift found was 7 degrees, with an associated uncertainty of 2 degrees. For the human enamel and both dental-resin composites the average shift values were found to be similar to their corresponding uncertainties (2 degrees). The results suggest that although human dentine has notable polarization properties, dental-resin composites and human enamel do not show significant polarization shifts.

  11. Interference and complementarity for two-photon hybrid entangled states

    SciTech Connect

    Nogueira, W. A. T.; Santibanez, M.; Delgado, A.; Saavedra, C.; Neves, L.; Lima, G.; Padua, S.

    2010-10-15

    In this work we generate two-photon hybrid entangled states (HESs), where the polarization of one photon is entangled with the transverse spatial degree of freedom of the second photon. The photon pair is created by parametric down-conversion in a polarization-entangled state. A birefringent double-slit couples the polarization and spatial degrees of freedom of these photons, and finally, suitable spatial and polarization projections generate the HES. We investigate some interesting aspects of the two-photon hybrid interference and present this study in the context of the complementarity relation that exists between the visibility of the one-photon and that of the two-photon interference patterns.

  12. Polarization and polarization fatigue in ferroelectrics

    NASA Astrophysics Data System (ADS)

    Du, Xiaofeng

    This thesis addresses some fundamental issues in ferroelectricity and its applications through a computational and experimental effort. It focuses on a variety of perovskite-type ferroelectric oxides and investigates the physical basis for spontaneous polarization, domain wall dynamics, and texture development in thin film applications. The dipole-dipole interactions between ionic species in perovskite-type materials have been calculated to determine the local field and the lattice instability. Different ferroelectric and anti-ferroelectric polarization transitions can be realized by taking into account the structure distortion of the parent perovskites. We find the local field is enhanced by short range disorder and its nature varies from disorder to disorder, causing polarization transitions in non-(100) directions. The molecular field theory has also been extended to layered perovskites, which favors in-plane polarization over c-polarization. These theoretical predictions are in agreement with the experimental observations of various perovskites and layered perovskites in both single crystal and thin film forms. Domain switching in PZT has been studied by probing the frequency dependency of polarization hysteresis. A picture of thermally activated domain wall movement is established from the frequency spectra of coercive field. The field dependence of domain wall bulging and the nature of the binding between pinning obstacles and the walls are inferred from such a study. Consistent with this picture, polarization fatigue can be defined as a process of increasing the resistance from pinning defects to domain wall motion. The chemical species that act as pinning defects have been identified through model experiments that control carrier injection, electrode interfaces, and film compositions. Based on these observations, a methodology is proposed to evaluate and predict the fatigue damage of both PZT and layered perovskite thin films. Processing of layered

  13. The Aquila Launch Vehicle - A hybrid propulsion space booster

    NASA Astrophysics Data System (ADS)

    Flittie, Kirk J.; Estey, Paul N.; Kniffen, R. J.

    1991-10-01

    The Aquila Launch Vehicle is the first low-cost hybrid rocket propulsion space booster capable of placing 1450-kg payloads into LEO with high availability and reliability, as well as unprecedented levels of production, ground, and flight operations safety. Since hybrid rockets cannot explode, they may be readily manufactured in light-industrial production facilities. Polar-orbit operations with commercial and government-project payloads are scheduled to begin from Vandenberg AFB in 1995.

  14. Parallel Polarization State Generation

    PubMed Central

    She, Alan; Capasso, Federico

    2016-01-01

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security. PMID:27184813

  15. Polarization of clouds

    NASA Astrophysics Data System (ADS)

    Goloub, Philippe; Herman, Maurice; Parol, Frederic

    1995-12-01

    This paper reports the main results concerning polarization by clouds derived from POLDER (polarization and directionality of earth's reflectances) airborne version. These results tend to confirm the high information content in the polarization (phase, altimetry). The preliminary results of EUCREX'94 (European Cloud Radiation Experiment) evidenced the drastically different polarized signatures for ice crystals and water droplets. Here we report systematic and statistically significative observations over the whole EUCREX data set. The results show that the cirrus exhibit their own signature. Preliminary observations performed during CLEOPATRA'91 (Cloud Experiment Ober Pfaffenhofen And Transport) and EUCREX'94 campaigns have shown the feasibility of cloud altimetry using spectral information (443 nm and 865 nm) of the polarized light over liquid water droplets clouds. Altimetry technique has been generalized on ASTEX-SOFIA'92 and EUCREX'94 data sets. All these results are presented and discussed in this paper.

  16. Precision Polarization of Neutrons

    NASA Astrophysics Data System (ADS)

    Martin, Elise; Barron-Palos, Libertad; Couture, Aaron; Crawford, Christopher; Chupp, Tim; Danagoulian, Areg; Estes, Mary; Hona, Binita; Jones, Gordon; Klein, Andi; Penttila, Seppo; Sharma, Monisha; Wilburn, Scott

    2009-05-01

    Determining polarization of a cold neutron beam to high precision is required for the next generation neutron decay correlation experiments at the SNS, such as the proposed abBA and PANDA experiments. Precision polarimetry measurements were conducted at Los Alamos National Laboratory with the goal of determining the beam polarization to the level of 10-3 or better. The cold neutrons from FP12 were polarized using optically polarized ^3He gas as a spin filter, which has a highly spin-dependent absorption cross section. A second ^ 3He spin filter was used to analyze the neutron polarization after passing through a resonant RF spin rotator. A discussion of the experiment and results will be given.

  17. Parallel Polarization State Generation

    NASA Astrophysics Data System (ADS)

    She, Alan; Capasso, Federico

    2016-05-01

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security.

  18. Parallel Polarization State Generation.

    PubMed

    She, Alan; Capasso, Federico

    2016-01-01

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security. PMID:27184813

  19. Cell polarity: mechanochemical patterning.

    PubMed

    Goehring, Nathan W; Grill, Stephan W

    2013-02-01

    Nearly every cell type exhibits some form of polarity, yet the molecular mechanisms vary widely. Here we examine what we term 'chemical systems' where cell polarization arises through biochemical interactions in signaling pathways, 'mechanical systems' where cells polarize due to forces, stresses and transport, and 'mechanochemical systems' where polarization results from interplay between mechanics and chemical signaling. To reveal potentially unifying principles, we discuss mathematical conceptualizations of several prototypical examples. We suggest that the concept of local activation and global inhibition - originally developed to explain spatial patterning in reaction-diffusion systems - provides a framework for understanding many cases of cell polarity. Importantly, we find that the core ingredients in this framework - symmetry breaking, self-amplifying feedback, and long-range inhibition - involve processes that can be chemical, mechanical, or even mechanochemical in nature. PMID:23182746

  20. Molecular content of polar-ring galaxies

    NASA Astrophysics Data System (ADS)

    Combes, F.; Moiseev, A.; Reshetnikov, V.

    2013-06-01

    We have searched for CO lines in a sample of 21 new morphologically determined polar-ring galaxies (of which nine are kinematically confirmed), obtained from a wide search in the Galaxy Zoo project by Moiseev and collaborators. Polar-ring galaxies (PRGs) are a unique class of objects, tracing special episodes in the galaxy mass assembly: they can be formed through galaxy interaction and merging, but also through accretion from cosmic filaments. Furthermore, they enable the study of dark matter haloes in three dimensions. The polar ring itself is a sub-system rich in gas, where molecular gas is expected, and new stars are formed. Among the sample of 21 PRGs, we have detected five CO-rich systems, that can now be followed up with higher spatial resolution. Their average molecular mass is 9.4 × 109M⊙, and their average gas fraction is 27% of their baryonic mass, with a range from 15 to 43%, implying that they have just accreted a large amount of gas. The position of the detected objects in the velocity-magnitude diagram is offset from the Tully-Fisher relation of normal spirals, as was already found for PRGs. This work is part of our multi-wavelength project to determine the detailed morphology and dynamics of PRGs, test through numerical models their formation scenario, and deduce their dark matter content and 3D-shape. Based on observations carried out with the IRAM 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).Spectra of detections are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5">130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/554/A11

  1. Polarization holographic optical recording of a new photochromic diarylethene

    NASA Astrophysics Data System (ADS)

    Pu, Shouzhi; Miao, Wenjuan; Chen, Anyin; Cui, Shiqiang

    2008-12-01

    A new symmetrical photochromic diarylethene, 1,2-bis[2-methyl-5-(3-methoxylphenyl)-3-thienyl]perfluorocyclopentene (1a), was synthesized, and its photochromic properties were investigated. The compound exhibited good photochromism both in solution and in PMMA film with alternating irradiation by UV/VIS light, and the maxima absorption of its closed-ring isomer 1b are 582 and 599 nm, respectively. Using diarylethene 1b/PMMA film as recording medium and a He-Ne laser (633 nm) for recording and readout, four types of polarization and angular multiplexing holographic optical recording were performed perfectly. For different types of polarization recording including parallel linear polarization recording, parallel circular polarization recording, orthogonal linear polarization recording and orthogonal circular polarization recording,have been accomplished successfully. The results demonstrated that the orthogonal circular polarization recording is the best method for polarization holographic optical recording when this compound was used as recording material. With angular multiplexing recording technology, two high contrast holograms were recorded in the same place on the film with the dimension of 0.78 μm2.

  2. Railgun hybrid armatures, experimental results and performance characteristics

    NASA Astrophysics Data System (ADS)

    Crawford, Roger; Keefer, Dennis; Sedghinasab, Ahad

    1991-01-01

    Six hybrid armature designs were evaluated in the UTSI one-centimeter square-bore railgun. Advanced diagnostic instrumentation was used to determine the characteristics of hybrid armatures which include a compound armature (current in plasma brushes to the metal armature followed by a plasma armature). The hybrid armatures were compact, with shorter current distributions than plasma armatures as measured with both optical and electromagnetic probes. Although the results are preliminary, due to the limited geometries investigated, the results are very encouraging. The short (less than one-bore-diameter) hybrids demonstrated efficiencies equal to or greater than plasma armatures and good armature stability.

  3. Hybrid mimics and hybrid vigor in Arabidopsis

    PubMed Central

    Wang, Li; Greaves, Ian K.; Groszmann, Michael; Wu, Li Min; Dennis, Elizabeth S.; Peacock, W. James

    2015-01-01

    F1 hybrids can outperform their parents in yield and vegetative biomass, features of hybrid vigor that form the basis of the hybrid seed industry. The yield advantage of the F1 is lost in the F2 and subsequent generations. In Arabidopsis, from F2 plants that have a F1-like phenotype, we have by recurrent selection produced pure breeding F5/F6 lines, hybrid mimics, in which the characteristics of the F1 hybrid are stabilized. These hybrid mimic lines, like the F1 hybrid, have larger leaves than the parent plant, and the leaves have increased photosynthetic cell numbers, and in some lines, increased size of cells, suggesting an increased supply of photosynthate. A comparison of the differentially expressed genes in the F1 hybrid with those of eight hybrid mimic lines identified metabolic pathways altered in both; these pathways include down-regulation of defense response pathways and altered abiotic response pathways. F6 hybrid mimic lines are mostly homozygous at each locus in the genome and yet retain the large F1-like phenotype. Many alleles in the F6 plants, when they are homozygous, have expression levels different to the level in the parent. We consider this altered expression to be a consequence of transregulation of genes from one parent by genes from the other parent. Transregulation could also arise from epigenetic modifications in the F1. The pure breeding hybrid mimics have been valuable in probing the mechanisms of hybrid vigor and may also prove to be useful hybrid vigor equivalents in agriculture. PMID:26283378

  4. Interplanetary magnetic sector polarity inferred from polar geomagnetic field observations

    NASA Technical Reports Server (NTRS)

    Friis-Christensen, E.; Lassen, K.; Wilcox, J. M.; Gonzalez, W.; Colburn, D. S.

    1971-01-01

    In order to infer the interplanetary sector polarity from polar geomagnetic field diurnal variations, measurements were carried out at Godhavn and Thule (Denmark) Geomagnetic Observatories. The inferred interplanetary sector polarity was compared with the polarity observed at the same time by Explorer 33 and 35 magnetometers. It is shown that the polarity (toward or away from the sun) of the interplanetary magnetic field can be reliably inferred from observations of the polar cap geomagnetic fields.

  5. Biodegradation of halogenated organic compounds.

    PubMed Central

    Chaudhry, G R; Chapalamadugu, S

    1991-01-01

    compounds. Recent developments in designing recombinant microorganisms and hybrid metabolic pathways are discussed. PMID:2030673

  6. Biodegradation of halogenated organic compounds.

    PubMed

    Chaudhry, G R; Chapalamadugu, S

    1991-03-01

    compounds. Recent developments in designing recombinant microorganisms and hybrid metabolic pathways are discussed. PMID:2030673

  7. Neutron Polarizers Based on Polarized 3He

    SciTech Connect

    William M. Snow

    2005-05-01

    The goal of this work, which is a collaborative effort between Indiana University, NIST, and Hamilton College, is to extend the technique of polarized neutron scattering into new domains by the development and application of polarized 3He-based neutron spin filters. After the IPNS experiment which measured Zeeman sp[litting in surface scattered neutrons using a polarized 3He cell as a polarization analyzer transporterd by car from Bloomington to Chicago, the Indiana work focused on technical developments to improve the 3He polarization of the Indiana compression system. The compression system was rebuilt with a new valve system which allows gas trapped in the dead volume of the compressors at the end of the piston stroke to be exhausted and conducted back to the optical pumping cell where it can be repolarized. We also incorporated a new intermediate storage volume made at NIST from 1720 glass which will reduce polarization losses between the compressors. Furthermore, we improved the stability of the 1083 nm laser by cooling the LMA rod. We achieved 60% 3he polarization in the optical pumping cell and 87% preservation of the polarization during compression. In parallel we built a magnetically-shielded transport solenoid for use on neutron scattering instruments such as POSY which achieves a fractional field uniformity of better than 10-3 per cm. The field was mapped using an automated 3D field mapping system for in-situ measurement of magnetic field gradients Diluted magnetic semiconductors offer many exciting opportunities for investigation of spintronic effects in solids and are certain to be one of the most active areas of condensed matter physics over then next several years. These materials can act as efficient spin injectors for devices that make use of spin-dependent transport phenomena. We just (late July 2002) finished a neutron reflectivity experiment at NIST on a GaMnAs trilayer film. This material is a ferromagnetic semiconductor which is of interest

  8. Polarization at the SLC

    SciTech Connect

    Moffeit, K.C.

    1988-10-01

    The Stanford Linear collider was designed to accommodate polarized electron beams. Longitudinally polarized electrons colliding with unpolarized positrons at a center of mass energy near the Z/sup 0/ mass can be used as novel and sensitive probes of the electroweak process. A gallium arsenide based photon emission source will provide a beam of longitudinally polarized electrons of about 45 percent polarization. A system of bend magnets and a superconducting solenoid will be used to rotate the spins so that the polarization is preserved while the 1.21 GeV electrons are stored in the damping ring. Another set of bend magnets and two superconducting solenoids orient the spin vectors so that longitudinal polarization of the electrons is achieved at the collision point with the unpolarized positrons. A system to monitor the polarization based on Moller and Compton scattering will be used. Nearly all major components have been fabricated and tested. Subsystems of the source and polarimeters have been installed, and studies are in progress. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. 8 refs., 16 figs., 1 tab.

  9. Spin polarization in half-metallic ferromagnets

    NASA Astrophysics Data System (ADS)

    Biasini, M.; Mills, A. P., Jr.

    2005-03-01

    Ferromagnetic contacts for spin injection and analysis are key components determining the performance of spintronic devices. For practical applications the materials for these contacts should have a high electron spin polarization at the Fermi surface (FS) at room temperature. We need to develop suitable new high Curie-temperature ferromagnets from the class of half metallic compounds that are theoretically ideal for spintronics [1]. We point out that a polarized slow positron probe combined with the two-dimensional angular correlation of annihilation radiation (2D-ACAR) technique [2] would allow unambiguous, direct, room-temperature determinations of the spin polarization of the conducting electrons at the FS of important candidate spintronic ferromagnetic thin films and single crystals. The electron spin polarization at the FS may be deduced directly from the amplitudes of the discontinuities in the electron occupation number at the Fermi momentum for two directions of the polarization of a positron probe relative to the saturating magnetic field direction [3]. Work supported in part by NSF grants DMR 0216927 and PHY 0140382 and by DOD/DARPA/DMEA, Award DMEA90-02-2-0216. [1] I. Zutic et al., Rev. Mod. Phys. 76, 323 (2004).[2] S. Berko, in Positron Solid-State Physics, Brant and Dupasquier, eds. (North-Holland, 1983) p. 64.[3] K. E. H. M. Hanssen et al., Phys. Rev. B 42, 1533 (1990).

  10. Two different types of optical hybrid qubits for teleportation in a lossy environment

    NASA Astrophysics Data System (ADS)

    Kim, Hoyong; Lee, Seung-Woo; Jeong, Hyunseok

    2016-08-01

    We investigate the performance of quantum teleportation under a lossy environment using two different types of optical hybrid qubits. One is the hybrid of a polarized single-photon qubit and a coherent-state qubit (type-I logical qubit), and the other is the hybrid of a qubit of the vacuum and the single-photon and a coherent-state qubit (type-II logical qubit). We show that type-II hybrid qubits are generally more robust to photon loss effects compared to type-I hybrid qubits with respect to fidelities and success probabilities of quantum teleportation.

  11. Review of Polarized Ion Sources

    NASA Astrophysics Data System (ADS)

    Zelenski, A.

    2016-02-01

    Recent progress in polarized ion sources development is reviewed. New techniques for production of polarized H‑ ion (proton), D‑ (D+) and 3He++ ion beams will be discussed. A novel polarization technique was successfully implemented for the upgrade of the RHIC polarized H‑ ion source to higher intensity and polarization. In this technique, a proton beam inside the high magnetic field solenoid is produced by ionization of the atomic hydrogen beam (from an external source) in the He-gas ionizer cell. Polarized electron capture from the optically-pumped Rb vapor further produces proton polarization (Optically Pumped Polarized Ion Source technique). The upgraded source reliably delivered beam for the 2013 polarized run in RHIC at S = 510 GeV. This was a major factor contributing to RHIC polarization increase to over 60 % for colliding beams. Feasibility studies of a new polarization technique for polarized 3He++ source based on BNL Electron Beam Ion Source is also discussed.

  12. North Polar Dunes

    NASA Technical Reports Server (NTRS)

    2006-01-01

    23 January 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark sand dunes in the north polar region of Mars. Surrounding much of the north polar ice cap are fields of sand dunes. In this case, the strongest winds responsible for the dunes blew off the polar cap (not seen here), from the north-northwest (upper left).

    Location near: 76.5oN, 63.7oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Summer

  13. GUIDE FOR POLARIZED NEUTRONS

    DOEpatents

    Sailor, V.L.; Aichroth, R.W.

    1962-12-01

    The plane of polarization of a beam of polarized neutrons is changed by this invention, and the plane can be flipped back and forth quicitly in two directions in a trouble-free manner. The invention comprises a guide having a plurality of oppositely directed magnets forming a gap for the neutron beam and the gaps are spaced longitudinally in a spiral along the beam at small stepped angles. When it is desired to flip the plane of polarization the magnets are suitably rotated to change the direction of the spiral of the gaps. (AEC)

  14. Association of electron conical distributions with upper hybrid waves

    NASA Technical Reports Server (NTRS)

    Menietti, J. D.; Lin, C. S.; Wong, H. K.; Bahnsen, A.; Gurnett, D. A.

    1992-01-01

    The particle and plasma wave data of the DE 1 and Swedish Viking satellites shows that intense (greater than 1 mV/m) upper hybrid emissions are sometimes present in the midaltitude polar magnetosphere on both the dayside cusp/cleft and the nightside auroral regions and that waves near the upper hybrid frequency are often associated with electron conical distributions. These observations are consistent with the production of at least some electron conical distributions by oblique heating of the electrons by upper hybrid waves. Examination of the wave data to establish the role of parallel heating remains to be performed.

  15. Association of electron conical distributions with upper hybrid waves

    SciTech Connect

    Menietti, J.D.; Lin, C.S.; Wong, H.K. ); Bahnsen, A. ); Gurnett, D.A. )

    1992-02-01

    The particle and plasma wave data of the DE 1 and Swedish Viking satellites shows that intense (> 1 mV/m) upper hybrid emissions are sometimes present in the mid-altitude polar magnetosphere on both the dayside cusp/cleft and the nightside auroral regions and that waves near the upper hybrid frequency are often associated with electron conical distributions. These observations are consistent with the production of at least some electron conical distributions by oblique heating of the electrons by upper hybrid waves. Examination of the wave data to establish the role of parallel heating remains to be performed.

  16. Effects of Substrate, Protein Environment, and Proximal Ligand Mutation on Compound I and Compound 0 of Chloroperoxidase

    NASA Astrophysics Data System (ADS)

    Lai, Wenzhen; Chen, Hui; Cho, Kyung-Bin; Shaik, Sason

    2009-07-01

    This paper investigates the enzyme chloroperoxidase (CPO) by means of hybrid quantum mechanical/molecular mechanical (QM/MM) calculations. The effects of anionic substrate, protein environment, and proximal ligand mutation on the high-valent iron-oxo species, compound I (Cpd I), and the ferric hydroperoxide complex, compound 0 (Cpd 0), are studied. The results indicate that the presence of an anionic substrate (acetate) and the protonation state of one critical residue (Glu104) have a considerable impact on the relative stabilities of Cpd I and Cpd 0. In the absence of the substrate or when the substrate is protonated, Cpd I is considerably more stable, and its formation barrier is smaller than in the case where the substrate is in its anionic state and when Glu104 is deprotonated. This trend, which is shown to be a simple manifestation of the Hammond principle, reproduces the experimental observation that the working pH of the enzyme is acidic. Furthermore, in the absence of substrate (or when it is protonated), the relative Cpd 0/Cpd I energies are found to be a good index of Cpd I stability in heme enzymes and to follow the experimental order: horseradish peroxidase (HRP) > CPO > P450. In silico mutation of the proximal ligand from cysteine to selenocysteine was found to have no effect at all on the properties of Cpd I (e.g., spin density on the chalcogen, Mössbauer parameters, etc.) and its relative stability to Cpd 0 or on the corresponding barrier for formation. This surprising finding shows that the polar CPO pocket applies a leveling effect that stabilizes the anionic forms of the proximal ligands (CysS- and CysSe-). This in turn means that the Se-Cpd I of the mutant CPO is observable.

  17. Dihedron dielectric loaded surface plasmon athermal polarization converter.

    PubMed

    Hassan, K; Leroy, F; Colas-des-Francs, G; Weeber, J-C

    2014-02-01

    We investigate numerically a novel plasmonic polarization converter relying on the excitation of a so-called dihedron dielectric loaded plasmon polariton. The dihedron dielectric loaded waveguide consists of a dielectric ridge implemented at the inner corner of a metal-coated dielectric step. For a dielectric ridge with a square cross section, the plasmon polariton modes supported by each side of the metallized step hybridize to create supermodes with crossed polarizations. We show that the two supermodes can be operated in a dual-mode interferometer configuration to perform an efficient (24 dB) TE-TM/TM-TE polarization conversion over typical distances below 30 μm at telecommunications wavelengths. In addition, on the basis of the thermo-optical properties of our device, we find that the dihedron plasmonic polarization converter is temperature insensitive. PMID:24487902

  18. Generation of arbitrary vector fields based on a pair of orthogonal elliptically polarized base vectors.

    PubMed

    Xu, Danfeng; Gu, Bing; Rui, Guanghao; Zhan, Qiwen; Cui, Yiping

    2016-02-22

    We present an arbitrary vector field with hybrid polarization based on the combination of a pair of orthogonal elliptically polarized base vectors on the Poincaré sphere. It is shown that the created vector field is only dependent on the latitude angle 2χ but is independent on the longitude angle 2ψ on the Poincaré sphere. By adjusting the latitude angle 2χ, which is related to two identical waveplates in a common path interferometric arrangement, one could obtain arbitrary type of vector fields. Experimentally, we demonstrate the generation of such kind of vector fields and confirm the distribution of state of polarization by the measurement of Stokes parameters. Besides, we investigate the tight focusing properties of these vector fields. It is found that the additional degree of freedom 2χ provided by arbitrary vector field with hybrid polarization allows one to control the spatial structure of polarization and to engineer the focusing field. PMID:26907066

  19. Polar flexoelectric in-plane and out-of-plane switching in bent core nematic mixtures

    NASA Astrophysics Data System (ADS)

    Elamain, Omaima; Hegde, Gurumurthy; Komitov, Lachezar

    2016-07-01

    Polar electro-optic response, arising from the coupling between an applied in-plane and out-of-plane dc electric field, respectively, and the flexoelectric polarization of bent core nematic liquid crystal mixtures with hybrid alignment is studied in conventional sandwich cells with homeotropic anchoring at one of the cell substrates and planar at the other. Such a hybrid alignment, however, results in a splay/bend elastic deformation of the nematic giving rise of a flexoelectric polarization. It was found that a pronounced polar electro-optic response, both in-plane and out of plane, took place in the bent core nematic mixtures at very low voltages due to the high flexoelectric polarization in these mixtures, compared with the one observed in calamitic liquid crystals.

  20. Polar Environmental Monitoring

    NASA Technical Reports Server (NTRS)

    Nagler, R. G.; Schulteis, A. C.

    1979-01-01

    The present and projected benefits of the polar regions were reviewed and then translated into information needs in order to support the array of polar activities anticipated. These needs included measurement sensitivities for polar environmental data (ice/snow, atmosphere, and ocean data for integrated support) and the processing and delivery requirements which determine the effectiveness of environmental services. An assessment was made of how well electromagnetic signals can be converted into polar environmental information. The array of sensor developments in process or proposed were also evaluated as to the spectral diversity, aperture sizes, and swathing capabilities available to provide these measurements from spacecraft, aircraft, or in situ platforms. Global coverage and local coverage densification options were studied in terms of alternative spacecraft trajectories and aircraft flight paths.