Sample records for coordination isomer selection


    NARCIS (Netherlands)



    The strength distribution of high-energy gamma-rays emitted in the statistical decay of the 156Dy compound nucleus, with E* = 92.5 MeV, has been measured inclusively and for selected decay pathways in which isomers in 149Dy, 151Dy and 152Dy were populated. For both spectra a deformation \\beta\\ = 0.3

  2. Tuning zinc coordination architectures by benzenedicarboxylate position isomers and bis(triazole) (United States)

    Peng, Yan-fen; Li, Ke; Zhao, Shan; Han, Shan-shan; Li, Bao-long; Li, Hai-Yan


    Three position isomers 1,2-, 1,3-, 1,4-benzenedicarboxylate and 1,4-bis(1,2,4-triazol-4-yl)benzene were used to assembly zinc(II) coordination polymers {[Zn2(btx)0.5(1,2-bdc)2(H2O)]·H2O}n (1), {[Zn(btx)(1,3-bdc)]·2H2O·(DMF)}n (2) and {[Zn(btx)(1,4-bdc)]·3H2O}n (3). 1 is a (3,4,4,4)-connected two-dimensional network with point symbol (42·6)(44·62)(43·62·8)(42·6·103). 2 shows a two-dimensional (4,4) network. 3 exhibits a 5-fold interpenetrated three-dimensional diamondoid network. The structural versatility shows that the structures of coordination polymers can be tuned by the position isomers ligands. The luminescence and thermal stability were investigated.

  3. Quantification of Structural Isomers via Mode-Selective Irmpd (United States)

    Polfer, Nicolas C.


    Mixtures of structural isomers can pose a challenge for vibrational ion spectroscopy. In cases where particular structures display diagnostic vibrations, these structures can be selectively "burned away". In ion traps, the ion population can be subjected to multiple laser shots, in order to fully deplete a particular structure, in effect allowing a quantification of this structure. Protonated para-amino benzoic acid (PABA) serves as an illustrative example. PABA is known to preferentially exist in the N-protonated (N-prot) form in solution, but in the gas phase it is energetically favorable in the O-protonated (O-prot) form. As shown in Figure 1, the N-prot structure can be kinetically trapped in the gas phase when sprayed from non-protic solvent, whereas the O-prot structure is obtained when sprayed from protic solvents, analogous to results by others [1,2]. y parking the light source on the diagnostic 3440 wn mode, the percentage of the O-prot structure can be determined, and by default the remainder is assumed to adopt the N-prot structure. It will be shown that the relative percentages of O-prot vs N-prot are highly dependent on the solvent mixture, going from close to 0% O-prot in non-protic solvents, to 99% in protic solvents. Surprisingly, water behaves much more like a non-protic solvent than methanol. It is observed that the capillary temperature, which aids droplet desolvation by black-body radiation in the ESI source, is critical to promote the appearance of O-prot structures. These results are consistent with the picture that a protic bridge mechanism is at play to facilitate proton transfer, and thus allow conversion from N-prot to O-prot, but that this mechanism is subject to appreciable kinetic barriers on the timescale of solvent evaporation. 1. J. Phys. Chem. A 2011, 115, 7625. 2. Anal. Chem. 2012, 84, 7857.

  4. Coordination and conformational isomers in mononuclear iron complexes with pertinence to the [FeFe] hydrogenase active site. (United States)

    Orthaber, Andreas; Karnahl, Michael; Tschierlei, Stefanie; Streich, Daniel; Stein, Matthias; Ott, Sascha


    A series of six mononuclear iron complexes of the type [Fe(X-bdt)(P(R)2N(Ph)2)(CO)] (P(R)2N(Ph)2 = 1,5-diaza-3,7-diphosphaoctane, bdt = benzenedithiolate with X = H, Cl2 or Me and R = Ph, Bn, Cyc or tert-Bu) was prepared. This new class of penta-coordinate iron complexes contains a free coordination site and a pendant base as essential structural features of the [FeFe]-hydrogenase active site. The bidentate nature of the P(R)2N(Ph)2 ligands was found to be crucial for the preferential formation of coordinatively unsaturated penta-coordinate complexes, which is supported by first principle calculations. IR-spectroscopic data suggest the presence of coordination isomers around the metal center, as well as multiple possible conformers of the P(R)2N(Ph)2 ligand. This finding is further corroborated by X-ray crystallographic and computational studies. (31)P{(1)H}-NMR- and IR-spectroscopic as well as electrochemical measurements show that the electronic properties of the complexes are strongly, and independently, influenced by the P-substituents at the P(R)2N(Ph)2 ligand as well as by modifications of the bdt bridge. These results illustrate the advantages of this modular platform, which allows independent and selective tuning through site specific modifications. Potential catalytic intermediates, namely singly reduced and protonated complexes, have been further investigated by spectroscopic methods and exhibit remarkable stability. Finally, their general capacity for electro-catalytic reduction of protons to molecular hydrogen was verified.

  5. Exploring Solvent Shape and Function Using - and Isomer-Selective Vibrational Spectroscopy (United States)

    Johnson, Mark


    We illustrate the new types of information than can be obtained through isomer-selective ``hole-burning'' spectroscopy carried out in the vibrational manifolds of Ar-tagged cluster ions. Three examples of increasing complexity will be presented where the changes in a solute ion are correlated with different morphologies of a surrounding solvent cage. In the first, we discuss the weak coupling limit where different hydration morphologies lead to small distortions of a covalent ion. We then introduce the more interesting case of the hydrated electron, where different shapes of the water network lead to dramatic changes in the extent of delocalization in the diffuse excess electron cloud. We then turn to the most complex case involving hydration of the nitrosonium ion, where different arrangements of the same number of water molecules span the range in behavior from simple solvation to actively causing a chemical reaction. The latter results are particularly interesting as they provide a microscopic, molecular-level picture of the ``solvent coordinate'' commonly used to describe solvent mediated processes.

  6. Selective Placement Program Coordinator (SPPC) Directory (United States)

    Office of Personnel Management — List of the Selective Placement Program Coordinators (SPPC) in Federal agencies, updated as needed. Users can filter the list by choosing a state and/or agency name.

  7. Lack of selective developmental toxicity of three butanol isomers administered by inhalation to rats. (United States)

    Nelson, B K; Brightwell, W S; Khan, A; Burg, J R; Goad, P T


    As part of an ongoing study of the developmental toxicology of industrial alcohols, this report presents the results of the teratology assessments of 1-butanol, 2-butanol, and t-butanol administered by inhalation to rats. Groups of approximately 15 Sprague-Dawley rats were exposed at 8000, 6000, 3500, or 0 ppm 1-butanol, 7000, 5000, 3500, or 0 ppm 2-butanol, or 5000, 3500, 2000, or 0 ppm t-butanol for 7 hr/day on Gestation Days 1-19 (sperm = 0). In each case, the highest concentration was selected to produce maternal toxicity. Dams were sacrificed on Gestation Day 20, and fetuses were individually weighed, tagged, and examined for external malformations. One-half of the fetuses were stained and examined for skeletal abnormalities, and the other half were examined for visceral defects using the Wilson technique. For each butanol isomer examined, the highest concentration (and the intermediate in some cases) was maternally toxic, as manifest by reduced weight gain and feed intake. Even at a maternally toxic dose, and in spite of a dose-dependent reduction in fetal weights for each isomer, the only teratogenicity observed was a slight increase in skeletal malformations (primarily rudimentary cervical ribs), seen with the highest concentration of 1-butanol. Thus, although teratogenicity was observed at 8000 ppm 1-butanol, and developmental toxicity was observed with each of the butyl alcohol isomers studied, concentrations 50 times the current permissible exposure limits for these three butanol isomers do not produce teratogenicity in rats.

  8. Selectivity of Brij-35 in Micellar Liquid Chromatographic Separation of Positional Isomers

    Directory of Open Access Journals (Sweden)

    Najma Memon


    Full Text Available Implementation of Brij-35, a nonionic surfactant, as a mobile phase for separation of positional isomers is investigated. Chromolith C-18 SpeedROD is used as a stationary phase. The effect of surfactant and organic modifier (propanol concentration on the separation of some selected isomers is studied and evaluated in terms of linear solvation energy relationship (LSER. Shape selectivity is assessed by α value of sorbic and benzoic acid, which is found to be 1.339 by using mobile phase composed of 0.5% aqueous solutions of Brij-35 and propanol in 9 : 1. Isomers of parabens, nitroanilines, nitrophenols, and quinolinols are successfully separated using mobile phases composed of various percentages of surfactant and propanol. System constants for nonionic MLC using LSER analysis show that hydrogen bond basicity and dipolarity may be major contributors to selectivity, while excess molar refraction helps fine-tuning the separation which also imparts unique selectivity to nonionic surfactants as compared to ionic ones.

  9. UTSA-74: A MOF-74 Isomer with Two Accessible Binding Sites per Metal Center for Highly Selective Gas Separation. (United States)

    Luo, Feng; Yan, Changsheng; Dang, Lilong; Krishna, Rajamani; Zhou, Wei; Wu, Hui; Dong, Xinglong; Han, Yu; Hu, Tong-Liang; O'Keeffe, Michael; Wang, Lingling; Luo, Mingbiao; Lin, Rui-Biao; Chen, Banglin


    A new metal-organic framework Zn2(H2O)(dobdc)·0.5(H2O) (UTSA-74, H4dobdc = 2,5-dioxido-1,4-benzenedicarboxylic acid), Zn-MOF-74/CPO-27-Zn isomer, has been synthesized and structurally characterized. It has a novel four coordinated fgl topology with one-dimensional channels of about 8.0 Å. Unlike metal sites in the well-established MOF-74 with a rod-packing structure in which each of them is in a five coordinate square pyramidal coordination geometry, there are two different Zn(2+) sites within the binuclear secondary building units in UTSA-74 in which one of them (Zn1) is in a tetrahedral while another (Zn2) in an octahedral coordination geometry. After activation, the two axial water molecules on Zn2 sites can be removed, generating UTSA-74a with two accessible gas binding sites per Zn2 ion. Accordingly, UTSA-74a takes up a moderately high and comparable amount of acetylene (145 cm(3)/cm(3)) to Zn-MOF-74. Interestingly, the accessible Zn(2+) sites in UTSA-74a are bridged by carbon dioxide molecules instead of being terminally bound in Zn-MOF-74, so UTSA-74a adsorbs a much smaller amount of carbon dioxide (90 cm(3)/cm(3)) than Zn-MOF-74 (146 cm(3)/cm(3)) at room temperature and 1 bar, leading to a superior MOF material for highly selective C2H2/CO2 separation. X-ray crystal structures, gas sorption isotherms, molecular modeling, and simulated and experimental breakthroughs comprehensively support this result.

  10. UTSA-74: A MOF-74 Isomer with Two Accessible Binding Sites per Metal Center for Highly Selective Gas Separation

    KAUST Repository

    Luo, Feng


    A new metal-organic framework Zn2(H2O)-(dobdc)·0.5(H2O) (UTSA-74, H4dobdc = 2,5-dioxido-1,4-benzenedicarboxylic acid), Zn-MOF-74/CPO-27-Zn isomer, has been synthesized and structurally characterized. It has a novel four coordinated fgl topology with one-dimensional channels of about 8.0 Å. Unlike metal sites in the wellestablished MOF-74 with a rod-packing structure in which each of them is in a five coordinate square pyramidal coordination geometry, there are two different Zn2+ sites within the binuclear secondary building units in UTSA-74 in which one of them (Zn1) is in a tetrahedral while another (Zn2) in an octahedral coordination geometry. After activation, the two axial water molecules on Zn2 sites can be removed, generating UTSA-74a with two accessible gas binding sites per Zn2 ion. Accordingly, UTSA-74a takes up a moderately high and comparable amount of acetylene (145 cm3/cm3) to Zn-MOF-74. Interestingly, the accessible Zn2+ sites in UTSA-74a are bridged by carbon dioxide molecules instead of being terminally bound in Zn-MOF-74, so UTSA-74a adsorbs a much smaller amount of carbon dioxide (90 cm3/cm3) than Zn-MOF-74 (146 cm3/cm3) at room temperature and 1 bar, leading to a superior MOF material for highly selective C2H2/CO2 separation. X-ray crystal structures, gas sorption isotherms, molecular modeling, and simulated and experimental breakthroughs comprehensively support this result. © 2016 American Chemical Society.

  11. Hydrogen Bond Networks of Three Cobalt Coordination Polymers Based on Bis(triazole) and Benzenebiscarboxylate Isomers%Hydrogen Bond Networks of Three Cobalt Coordination Polymers Based on Bis(triazole) and Benzenebiscarboxylate Isomers

    Institute of Scientific and Technical Information of China (English)

    钱新; 王菊; 崔艳锋; 李宝龙; 李海燕


    Three hydrogen bond networks of cobalt(II) coordination polymers { [Co(btp)2(H2O)2]·2(l,2-Hbdc)·2H2O}n (1), { [Co(btp) (1,3 -bdc)(H2O)]·1.5H2O } n (2) and { [Co(btp)2(H2O)2]·(1,4-bdc) } n (3) were synthesized by 1,3 -bis(1,2,4- triazol- 1-yl)propane (btp) and benzenedicarboxylate position isomers. Complex 1 is comprised of [Co(btp)z(H20)]2n+ 1D cation chains, 1,2-Hbdc anions and lattice water molecules. The structure of 2 is an undulated 2D (4,4) network. Two adjacent networks interpenetrate each other to form a new 2D double-layers network which is sustained by the hydrogen bond interactions in 2. Complex 3 is comprised of [Co(btp)z(H20)]n2n+ 1D cation chains and 1,4-bdc2 anions. These [Co(btp)2(H2O)]n^2+ 1D cations and 1,2-Hbdc-/1,4-bdc2- anions form 2D hydrogen bond networks in 1 and 3. The thermal stabilities of 1, 2 and 3 were investigated.

  12. Two organoantimony (V) coordination complexes modulated by isomers of trifluoromethylbenzoate ligands: Syntheses, crystal structure, photodegradation properties (United States)

    Zhang, Xiao-Yin; Cui, Lian-sheng; Zhang, Xia; Jin, Fan; Fan, Yu-Hua


    Two organoantimony (V) coordination complexes, namely Ph3Sb(2-tmbc) (1) and Ph3Sb(3-tmbc) (2) (2-tmbc = 2-(trifluoromethyl)benzoic carboxyl, 3-tmbc = 3-(trifluoromethyl)benzoic carboxyl) have been synthesized and characterized by IR spectra, elemental analysis, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that complexes 1 and 2 show different architectures by the intermolecular hydrogen bonds (Csbnd H⋯F), complex 1 displays an 1D straight chain structure, while complex 2 shows an 1D zigzag chain structure. The photodegradation properties of complexes 1 and 2 has been investigated in organic dyes (RhB, MV, MB) the results indicated that the two complexes are good candidates for the photocatalytic degradation of three dyes. The tentative photocatalytic degradations mechanism is discussed.

  13. Reverse shape selectivity in the liquid-phase adsorption of xylene isomers in zirconium terephthalate MOF UiO-66. (United States)

    Moreira, Mariana A; Santos, João C; Ferreira, Alexandre F P; Loureiro, José M; Ragon, Florence; Horcajada, Patricia; Shim, Kyu-E; Hwang, Young-K; Lee, U-Hwang; Chang, Jong-S; Serre, Christian; Rodrigues, Alírio E


    Powder, agglomerates, and tablets of the microporous zirconium(IV) terephthalate metal-organic framework UiO-66 were evaluated for the selective adsorption and separation of xylene isomers in the liquid phase using n-heptane as the eluent. Pulse experiments, performed at 313 K in the presence of n-heptane, revealed the o-xylene preference of this material, which was further confirmed by binary and multicomponent breakthrough experiments in the presence of m- and p-xylene, resulting in selectivities at 313 K of 1.8 and 2.4 with regards to m-xylene and p-xylene, respectively. Additionally, because p-xylene is the less retained isomer, UiO-66 presents a selectivity pattern that is reverse of that of the xylenes' molecular dimension with respect to shape selectivity. The shaping of the material as tablets did not significantly change its selectivity toward the o-xylene isomer or toward p-xylene, which was the less retained isomer, despite a loss in capacity. Finally, the selectivity behavior of UiO-66 in the liquid n-heptane phase makes it a suitable material for o-xylene separation in the extract (heavy product) or p-xylene separation in the raffinate (light product) by simulated moving bed technology.

  14. Solid-vapor sorption of xylenes: prioritized selectivity as a means of separating all three isomers using a single substrate. (United States)

    Lusi, Matteo; Barbour, Leonard J


    A Werner complex is highly selective for o-xylene in a vapor mixture containing all three isomers. However, in the absence of o-xylene, the substrate shows similar selectivity for m-xylene over p-xylene. Kinetic studies show a different trend whereby m-xylene is absorbed most rapidly, implying that thermodynamic factors must be responsible for the selectivity. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Molecular tectonics: p-H-thiacalix[4]arene pyridyl appended positional isomers as tectons for the formation of 1D and 2D mercury coordination networks. (United States)

    Ovsyannikov, A; Ferlay, S; Solovieva, S E; Antipin, I S; Konovalov, A I; Kyritsakas, N; Hosseini, M W


    Three p-H-thiacalix[4]arene pyridyl appended coordinating tectons (2-4) in a 1,3-alternate conformation have been prepared and structurally characterised in the solid state. These compounds are positional isomers differing only by the position of the nitrogen atom on the pyridyl ring. Their combinations with HgCl2 lead to the formation of 1- and 2-D neutral mercury coordination networks. Whereas for tecton 2 (ortho isomer) a 2D architecture resulting from the bridging of consecutive tectons by the mononuclear HgCl2 unit is obtained, for tecton 3 (meta isomer) again a 2D network is formed. However, in that case, the interconnection of consecutive organic tectons 3 takes place through a binuclear Hg2Cl4 species. Finally, in the case of tecton 4 (para position), a 1D ribbon type double chain arrangement resulting from the bridging of consecutive tectons by trinuclear Hg3Cl6 units followed by the interconnection of two chains through the fusion of the trinuclear centres into a hexanuclear node is observed.

  16. Development of a RIMMPA-TOFMS. Isomer selective soft ionization of PCDDs/DFs

    Energy Technology Data Exchange (ETDEWEB)

    Kirihara, N.; Haruaki, Y.; Mizuho, T.; Kenji, T.; Norifumi, K.; Yasuo, S. [IDX Corporation, Tokyo (Japan); Toru, S. [JFE Engineering Corporation, Kanagawa (Japan)


    Laser mass spectrometry is an excellent technique for analyzing the dioxin discharge that changes continuously in a waste incinerator because of its rapidity and sensitivity. This instrument is being developed by many research groups around the world. A laser has also been proposed that uses a pico-second or femto-second pulse width in order to ionize softly for the polychlorodibenzo-p-dioxins and polychlorodibenzofurans (PCDDs/DFs) because of the short excitation lifetime of their molecules. In contrast, we have developed a new laser mass spectrometer, RIMMPA-TOFMS (Resonance Ionization with Multi-Mirror-System Photon Accumulation coupled with Time of Flight Mass Spectrometry), based on a two-color-two-photon ionization scheme and using a nanosecond pulse laser, which enables isomer selective soft ionization for the PCDDs/DFs, and which has high-sensitivity performance with a minimum limit of detection of 3.7 pptv (signal-to-noise ratio S/N = 3, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TeCDD)). In particular, a pulse valve has been developed that can operate under a high-temperature condition and produce a supersonic jet under the choke-flow condition, enabling isomer selective soft ionization of the PCDDs/DFs. If the supersonic jet gas ejected from our short pulse valve can not only be cooled to cryogenic temperature, but also be ordered uniformly so that the collisions between particles are minimized and the excitation lifetime of its compounds becomes longer, then the nano-second pulse width laser will also ionize softly. In this paper, we report the experimental results of the following PCDDs/DFs detected by RIMMPA-TOFMS: 2,3,7,8-TeCDD, 1,2,3,7,8-pentachlorodibenzofuran (PnCDF) and 2,3,4,7,8- PnCDF, and the mass and wavelength two-dimensional map database for the 14 kinds of PCDDs/DFs.

  17. Binding Energy Calculation of Patchouli Alcohol Isomer Cyclooxygenase Complexes Suggested as COX-1/COX-2 Selective Inhibitor

    Directory of Open Access Journals (Sweden)

    Sentot Joko Raharjo


    Full Text Available To understand the structural features that dictate the selectivity of the two isoforms of the prostaglandin H2 synthase (PGHS/COX, the three-dimensional (3D structure of COX-1/COX-2 was assessed by means of binding energy calculation of virtual molecular dynamic with using ligand alpha-Patchouli alcohol isomers. Molecular interaction studies with COX-1 and COX-2 were done using the molecular docking tools by Hex 8.0. Interactions were further visualized by using Discovery Studio Client 3.5 software tool. The binding energy of molecular interaction was calculated by AMBER12 and Virtual Molecular Dynamic 1.9.1 software. The analysis of the alpha-Patchouli alcohol isomer compounds showed that all alpha-Patchouli alcohol isomers were suggested as inhibitor of COX-1 and COX-2. Collectively, the scoring binding energy calculation (with PBSA Model Solvent of alpha-Patchouli alcohol isomer compounds (CID442384, CID6432585, CID3080622, CID10955174, and CID56928117 was suggested as candidate for a selective COX-1 inhibitor and CID521903 as nonselective COX-1/COX-2.

  18. Facile and selective synthesis of oligothiophene-based sensitizer isomers: an approach toward efficient dye-sensitized solar cells. (United States)

    Feng, Quanyou; Zhang, Qian; Lu, Xuefeng; Wang, Hong; Zhou, Gang; Wang, Zhong-Sheng


    Two sets of isomeric organic dyes with n-hexyl (DH and AH) or 2-ethylhexyl (DEH and AEH) groups substituted at the spacer part have been designed and straightforwardly synthesized via a facile and selective synthetic route. The structure difference between the isomers stands at the position of the incorporated alkyl chains which are introduced into the terthiophene spacer close to the donor (D) or anchor (A) side. The relationship between the isomeric structures and the optoelectronic properties are systematically investigated. It is found that, in the D series dyes, the alkyl group is much closer to the aromatic donor moiety, which brings about strong steric hindrance and therefore causes a remarkable twist in the molecular skeleton. In contrast, a more planar chemical structure and more effective π-conjugation are realized in the A series dye isomers. Consequently, the A series isomeric dyes demonstrate bathochromically shifted absorption bands, resulting in the improved light-harvesting capability and enhanced photo-generated current. However, the D series isomeric dyes with more twisted molecular skeleton have suppressed the intermolecular interactions and retarded the charge recombination more efficiently, which induces higher open-circuit photovoltage. Combining the two effects on the performance of the fabricated dye-sensitized solar cells (DSSC), the influence from the short-circuit photocurrent plays a more significant role on the power conversion efficiency (η). As a result, isomer AEH-based DSSC with quasi-solid-state electrolyte displays the highest η of 7.10% which remained at 98% of the initial value after continuous light soaking for 1000 h. Promisingly, a η of 8.66% has been achieved for AEH-based DSSC with liquid electrolyte containing Co(II)/(III) redox couple. This work presents the crucial issue of molecular engineering and paves a way to design organic sensitizers for highly efficient and stable DSSCs.

  19. Bioaccumulation of HCH isomers in selected macroinvertebrates from the Elbe River: sources and environmental implications. (United States)

    Kolaříková, Kateřina; von Tümpling, Wolf; Bartels, Peter


    Sediments of the Elbe River have been extremely polluted by contaminants originating from previous large-scale hexachlorocyclohexane (HCH) production and the application of γ-HCH (lindane) in its catchment in the second half of the twentieth century. In order to gain knowledge on bioaccumulation processes at lower trophic levels, field investigations of HCHs in macroinvertebrates were carried out along the longitudinal profile of the Elbe and tributary. Among the sites studied, concentrations in macroinvertebrates ranged within five orders of magnitude (0.01-100 μg/kg). In general, lower values of HCH isomers were observed at all Czech sites (mostly Elbe catchment, and these concentrations are decreasing over time to a lesser extent than γ-HCH. Higher HCH concentrations in sediments in the springtime are considered to be the result of erosion and transport processes during and after spring floods, and lower concentrations at sites downstream are thought to be caused by the time lapse involved in the transportation of contaminated particles from upstream. In addition, comparison with fish (bream) data from the literature revealed no increase in tissue concentrations between invertebrates and fish.

  20. Automated selection of LEDs by luminance and chromaticity coordinate

    CERN Document Server

    Fischer, Ulrich H P; Reinboth, Christian


    The increased use of LEDs for lighting purposes has led to the development of numerous applications requiring a pre-selection of LEDs by their luminance and / or their chromaticity coordinate. This paper demonstrates how a manual pre-selection process can be realized using a relatively simple configuration. Since a manual selection service can only be commercially viable as long as only small quantities of LEDs need to be sorted, an automated solution suggests itself. This paper introduces such a solution, which has been developed by Harzoptics in close cooperation with Rundfunk Gernrode. The paper also discusses current challenges in measurement technology as well as market trends.

  1. Toward understanding the influence of ethylbenzene in p-xylene selectivity of the porous titanium amino terephthalate MIL-125(Ti): adsorption equilibrium and separation of xylene isomers. (United States)

    Moreira, Mariana A; Santos, João C; Ferreira, Alexandre F P; Loureiro, José M; Ragon, Florence; Horcajada, Patricia; Yot, Pascal G; Serre, Christian; Rodrigues, Alírio E


    The potential of the porous crystalline titanium dicarboxylate MIL-125(Ti) in powder form was studied for the separation in liquid phase of xylene isomers and ethylbenzene (MIL stands for Materials from Institut Lavoisier). We report here a detailed experimental study consisting of binary and multi-component adsorption equilibrium of xylene isomers in MIL-125(Ti) powder at low (≤0.8 M) and bulk (≥0.8 M) concentrations. A series of multi-component breakthrough experiments was first performed using n-heptane as the eluent at 313 K, and the obtained selectivities were compared, followed by binary breakthrough experiments to determine the adsorption isotherms at 313 K, using n-heptane as the eluent. MIL-125(Ti) is a para-selective material suitable at low concentrations to separate p-xylene from the other xylene isomers. Pulse experiments indicate a separation factor of 1.3 for p-xylene over o-xylene and m-xylene, while breakthrough experiments using a diluted ternary mixture lead to selectivity values of 1.5 and 1.6 for p-xylene over m-xylene and o-xylene, respectively. Introduction of ethylbenzene in the mixture results however in a decrease of the selectivity.

  2. Pulse-fluence-specified optimal control simulation with applications to molecular orientation and spin-isomer-selective molecular alignment

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Masataka; Nakashima, Kaoru; Ohtsuki, Yukiyoshi [Department of Chemistry, Graduate School of Science, Tohoku University 6-3 Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8578 (Japan)


    We propose an optimal control simulation with specified pulse fluence and amplitude. The simulation is applied to the orientation control of CO molecules to examine the optimal combination of THz and laser pulses, and to discriminate nuclear-spin isomers of {sup 14}N{sub 2} as spatially anisotropic distributions.

  3. Post-synthetic transformation of a Zn( ii ) polyhedral coordination network into a new supramolecular isomer of HKUST-1

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yao [State Key Laboratory of Medicinal Chemical Biology; Nankai University; Tianjin 300071; P. R. China; College of Pharmacy; Wojtas, Lukasz [Department of Chemistry; University of South Florida; 4202 East Fowler Avenue; Tampa; USA; Ma, Shengqian [Department of Chemistry; University of South Florida; 4202 East Fowler Avenue; Tampa; USA; Zaworotko, Michael J. [Department of Chemistry & Environmental Sciences, Bernal Institute, University of Limerick; Limerick; Republic of Ireland; Zhang, Zhenjie [College of Chemistry, Nankai University; Tianjin; P. R. China; State Key Laboratory of Medicinal Chemical Biology; Nankai University


    A Zn-based porphyrin containing metal–organic material (porphMOM-1) was post-synthetically transformed into a Cu-based porphyrin-encapsulating metal–organic material (porph@HKUST-1-β).HKUST-1-βis a new supramolecular isomer ofHKUST-1.

  4. The Preparation and Characterization of the Geometric Isomers of a Coordination Complex: cis- and trans-bis Glycinato Copper (II) Monohydrates. (United States)

    O'Brien, Paul


    Preparation of cis and trans isomers of the kinetically labile bis glycinato copper (II) has a number of advantages including its facility, economy, ready theoretical interpretation, and biological relevance. Background information, laboratory procedures, results/discussion are provided for this experiment which can be completed in a single,…

  5. Structural and photophysical characterisation of coordination and optical isomers of mononuclear ruthenium(II) polypyridyl 1,2,4-triazole complexes

    NARCIS (Netherlands)

    Browne, Wesley R.; Hesek, Dusan; Gallagher, John F.; O’Connor, Christine M.; Killeen, J. Scott; Aoki, Fumiko; Ishida, Hitoshi; Inoue, Yoshihisa; Villani, Claudio; Vos, Johannes G.


    The X-ray crystal structure of the N2 isomers of the Ru(bipy)2 complexes of Hphpztr (1) and Hpztr (2), (bipy = 2,2'-bipyridine, Hphpztr = 2-(5'-phenyl-4'H-[1,2,4]triazol-3'-yl)pyrazine and Hpztr = 2-(4'H-[1,2,4]triazol-3'-yl)pyrazine) are reported. The molecular structure obtained for 2 demonstrates

  6. Metal selective co-ordinative self-assembly of -donors

    Indian Academy of Sciences (India)

    Ankit Jain; K Venkata Rao; Ankita Goswami; Subi J George


    Metal selective co-ordinative nanostructures were constructed by the supramolecular co-assembly of pyridine appended TTF (TTF-Py) and pyrene (PYR-Py) derivatives in appropriate solvent composition mixtures with metal ions.Microscopic analyses show that TTF-Py shows distinctive morphology with either of these metal ions, forming I-D tapes with 1:1 Pb2+ complex and 2-D sheets with 1:2 Zn2+ complex. A rationale has been provided from molecular level packing for such hierarchical changes. In case of Cu2+, we have observed an anomalous binding of metal ion to the core sulphur groups causing redox changes in the TTF core. PYR-Py on the other hand is shown to be a fluorescent sensor for Pb2+, Zn2+, Hg2+ and Ag+. With different fluorescent response for metal complexes, we essentially obtained similar 1-D assemblies suggesting similar binding modes for all of them. Supramolecular approach through which morphology of an electron donor moiety can be engineered by metal ions can be a new tool in nanoelectronics.

  7. Descriptions of Selected State Local Interagency Coordinating Councils (LICCs). (United States)

    Shackelford, Jo, Ed.

    The Individuals with Disabilities Education Act (IDEA) requires that each state participating in the federal early intervention program establish a state interagency coordinating council (SICC) to assist and advise the state lead agencies in achieving a coordinated service delivery system. Some states have also established local interagency…

  8. Structure selection and coordination in dual-channel supply chains

    Directory of Open Access Journals (Sweden)

    Jingjing Cai


    Full Text Available Purpose: This paper investigates the influence of channel structures and channel coordination on the supplier, the retailer and the entire supply chain in the context of two different kinds of marketing models: The common retailer and the exclusive shop.Methodology: With suppliers who manufacture the alternative commodities and retailers in the dual-channel supply chains as the object of the research, this paper compares suppliers' profits, consumer utility without coordination and contrasts suppliers' and retailers' profits with coordination to determine the range of the revenue sharing rates and which parameters are related.Findings: The analysis suggests the preference lists of the supplier and the retailer over channel structures with and without coordination are different, and depend on parameters like channel basic demand, channel cost and channel substitutability.Originality/value: In this research, new sales model for two suppliers should choose the same retailer or the exclusive retailers to sell their commodities.

  9. Bay Functionalized Perylenediimide with Pyridine Positional Isomers: NIR Absorption and Selective Colorimetric/Fluorescent Sensing of Fe(3+) and Al(3+) Ions. (United States)

    Kundu, Anu; Pitchaimani, Jayaraman; Madhu, Vedichi; Sakthivel, Pachagounder; Ganesamoorthy, Ramasamy; Anthony, Savarimuthu Philip


    Bay functionalized perylene diimide substituted with pyridine isomers, (2-pyridine (2HMP-PDI), 3-pyridine (3-HMP-PDI) and 4-pyridine (4-HMP-PDI)) have been synthesized and explored for selective coloro/fluorimetric sensing of heavy transition metal ions. HMP-PDIs showed strong NIR absorption (760-765 nm) in DMF. The absorption and fluorescence of HMP-PDIs have been tuned by make use of pyridine isomers. Reddish-orange color was observed for 2-HMP-PDI (λmax = 437, 551, 765 nm) whereas 4-HMP-PDI exhibited light green (λmax = 432, 522, 765 nm). 3-HMP-PDI showed orange-yellow (λmax = 431, 524, 762 nm). The fluorescence spectra of 2-, 3- and 4-HMP-PDI showed λmax at 585, 538, 546 nm, respectively. Interestingly, HMP-PDI dyes showed selective color change (intense pink color) and fluorescence quenching for Fe(3+) and Al(3+) metal ions in DMF. Absorbance spectra revealed complete disappearance of NIR absorption and intensification/appearance of new peak at lower wavelength. The concentration dependent studies suggest that 4-HMP-PDI can detect up to 36.52 ppb of Fe(3+) and 43.12 ppb of Al(3+) colorimetrically. The interference studies in presence of other metal ions confirmed the good selectivity for Fe(3+) and Al(3+). The mechanistic studies indicate that Lewis acidic character of Fe(3+) and Al(3+) ions were responsible for selective color change and fluorescence quenching.

  10. Residue-based Coordinated Selection and Parameter Design of Multiple Power System Stabilizers (PSSs)

    DEFF Research Database (Denmark)

    Su, Chi; Hu, Weihao; Fang, Jiakun


    data from time domain simulations. Then a coordinated approach for multiple PSS selection and parameter design based on residue method is proposed and realized in MATLAB m-files. Particle swarm optimization (PSO) is adopted in the coordination process. The IEEE 39-bus New England system model...... as the test system is built in DIgSIELNT PowerFactory 14.0, in which the proposed coordination method is validated by time domain simulations and modal analysis....

  11. o-, m-, and p-Pyridyl isomer effects on construction of 1D loop-and-chains: Silver(I) coordination polymers with Y-type tridentate ligands (United States)

    Kim, Jeong Gyun; Cho, Yoonjung; Lee, Haeri; Lee, Young-A.; Jung, Ok-Sang


    Self-assembly of silver(I) hexafluorophosphate with unique Y-type tridentate ligands (2,6-bis[(2-picolinoyloxy-5-methylphenyl)methyl]-p-tolylpicolinate (o-L), 2-nicotinoyloxy- (m-L), and 2-isonicotinoyloxy- (p-L)) produces single crystals consisting of 1D loop-and-chain coordination polymers of [Ag(o-L)](PF6)·Me2CO·CHCl3, [Ag(m-L)](PF6)·Me2CO, and [Ag3(p-L)2](PF6)3·2H2O·2C2H5OH·4CH2Cl2 with quite different trigonal prismatic, trigonal, and linear silver(I) coordination geometry, respectively. Coordinating ability of the three ligands for AgPF6 is in the order of p-L > o-L > m-L. The solvate molecules of [Ag(o-L)](PF6)·Me2CO·CHCl3 can be removed, and be replaced reversibly in the order of acetone ≫ chloroform ≈ dichloromethane ≫ benzene, without destruction of its skeleton.

  12. Coordinated transmit and receive processing with adaptive multi-stream selection

    CERN Document Server

    An, HongSun; Han, DongKeol; Chang, KyungHi


    In this paper, we propose an adaptive coordinated Tx-Rx beamforming scheme for inter-user interference cancellation, when a base station (BS) communicates with multiple users that each has multiple receive antennas. The conventional coordinated Tx-Rx beamforming scheme transmits a fixed number of data streams for each user regardless of the instantaneous channel states, that is, all the users, no matter they are with ill-conditioned or well-conditioned channels, have the same number of data streams. However, in the proposed adaptive coordinated Tx-Rx beamforming scheme, we adaptively select the number of streams per user to solve the inefficient problem of the conventional coordinated Tx-Rx beamforming scheme. As a result, the BER performance is improved. Simulation results show that the proposed algorithm outperforms the conventional co-ordinated Tx-Rx beamforming algorithm by 2.5dB at a target BER of 10^-2

  13. Utilizing reversible copper(II) peptide coordination in a sequence-selective luminescent receptor. (United States)

    Stadlbauer, Stefan; Riechers, Alexander; Späth, Andreas; König, Burkhard


    Although vast information about the coordination ability of amino acids and peptides to metal ions is available, little use of this has been made in the rational design of selective peptide receptors. We have combined a copper(II) nitrilotriacetato (NTA) complex with an ammonium-ion-sensitive and luminescent benzocrown ether. This compound revealed micromolar affinities and selectivities for glycine- and histidine-containing sequences, which closely resembles those of copper(II) ion peptide binding: the two free coordination sites of the copper(II) NTA complex bind to imidazole and amido nitrogen atoms, replicating the initial coordination steps of non-complexed copper(II) ions. The benzocrown ether recognizes the N-terminal amino moiety intramolecularly, and the significantly increased emission intensity signals the binding event, because only if prior coordination of the peptide has taken place is the intramolecular ammonium ion-benzocrown ether interaction of sufficient strength in water to trigger an emission signal. Intermolecular ammonium ion-benzocrown ether binding is not observed. Isothermal titration calorimetry confirmed the binding constants derived from emission titrations. Thus, as deduced from peptide coordination studies, the combination of a truncated copper(II) coordination sphere and a luminescent benzocrown ether allows for the more rational design of sequence-selective peptide receptors.

  14. The molecular clock in terms of quantum information processing of coherent states, entanglement and replication of evolutionarily selected decohered isomers. (United States)

    Cooper, W Grant


    Evolutionary pressures have selected quantum uncertainty limits -ΔxΔp ( x ) ≥ 1/2ħ-to operate on metastable amino DNA protons. This introduces a probability of molecular clock arrangement, keto-amino → enol-imine, where product protons are entangled and participate in coupled quantum oscillation at frequencies of ∼ 10(13) s(-1). The ket "seen by" the transcriptase, reading a coherent enol-imine G'-state, is |φ >= α| + + > +β|+- > +γ|-+ > +δ|-->. The transcriptase implements its measurement and generates an output qubit of observable genetic specificity information in an interval Δt ≪ 10(-13) s. These quantum measurements can specify the relative distribution of coherent G'-C' states at time of measurement. The ensuing quantum entanglement between coherent protons and transcriptase units is utilized as a resource to generate proper decoherence and introduce selected time-dependent substitutions, ts, and deletions, td. Topal-Fresco ts are G'202 → T, G'002 → C, *G020(0) → A and *C202(2) → T, whereas td are exhibited at coherent *A-*T sites. Variation in clock 'tic-rate' is a consequence of clock introduction of initiation codons - UUG, CUG, AUG, GUG - and stop codons, UAA, UAG, UGA. Using approximate quantum methods for times t < ∼ 100 y, the probability, P(t), of keto-amino → enolimine arrangement is P ( ρ )(t) = 1/2(γ ( ρ )/ħ)(2) t (2) where γ ( ρ ) is the energy shift. This introduces a quantum Darwinian evolution model which provides insight into biological consequences of coherent states populating human genes, including inherited (CAG)( n ) repeat tracts.

  15. Overcoming Statistical Complexity: Selective Coordination of Three Different Metal Ions to a Ligand with Three Different Coordination Sites. (United States)

    Akine, Shigehisa; Matsumoto, Takashi; Nabeshima, Tatsuya


    In general, it is difficult to selectively introduce different metal ions at specific positions of a cluster-like structure. This is mainly due to statistical problems as well as the reversibility of the formation of coordination bonds. To overcome this statistical problem, we used a carefully designed ligand, H6 L, which can accommodate three different kinds of metal ions in three types of coordination sites. The complex [LNiZn2La](3+), which contains three different metals, was quantitatively obtained by a stepwise procedure, but different products were obtained when the metal ions were added in a different order. However, equilibration studies indicated that this complex was almost solely formed among 54 (=3×3×3H2) possible products upon heating; the formation efficiency (ca. 100%) was significantly higher than the statistical probability (2.47%). Such carefully designed ligands should be useful for the synthesis multimetallic systems, which are of interest because of the interplay between the different metals.

  16. Selective Adsorption of CO2 from Light Gas Mixtures Using a Structurally Dynamic Porous Coordination Polymer**

    Energy Technology Data Exchange (ETDEWEB)

    Kristi L. Kauffman, Jeffrey T. Culp, Andrew J. Allen, Laura Espinal, Winnie Wong-Ng, Thomas D.


    The selective adsorption of CO{sub 2} from mixtures with N{sub 2}, CH{sub 4}, and N{sub 2}O in a dynamic porous coordination polymer (see monomer structure) was evaluated by ATR-FTIR spectroscopy, GC, and SANS. All three techniques indicate highly selective adsorption of CO{sub 2} from CO{sub 2}/CH{sub 4} and CO{sub 2}/N{sub 2} mixtures at 30 C, with no selectivity observed for the CO{sub 2}/N{sub 2}O system.

  17. Toward Coordinated Colloids: Site-Selective Growth of Titania on Patchy Silica Particles (United States)

    Bae, Changdeuck; Kim, Hyunchul; Montero Moreno, Josep M.; Yi, Gi-Ra; Shin, Hyunjung


    Rational synthesis of coordinated spherical colloids is reported by site-selective growth of secondary hemispherical patches on primary spherical particles with quasi-defined coordination numbers and positions. We clarify the importance of mass transport phenomena on the site-specific secondary nucleation/growth in nanoparticulate colloidal systems. By comparing ultrasonic and conventional agitation during patch growth, we found that enhanced mass transfer is the key to controlled, homogeneous transport of the molecular precursors in a solvent onto the nanoparticles. With chemically defined nucleation sites, the surfaces of spherical silica particles were modified for use as a new kind of colloid with patches at desired coordination positions. Our observations represent a significant breakthrough in colloidal chemistry and self-assembly.

  18. Deadlines in space: Selective effects of coordinate spatial processing in multitasking. (United States)

    Todorov, Ivo; Del Missier, Fabio; Konke, Linn Andersson; Mäntylä, Timo


    Many everyday activities require coordination and monitoring of multiple deadlines. One way to handle these temporal demands might be to represent future goals and deadlines as a pattern of spatial relations. We examined the hypothesis that spatial ability, in addition to executive functioning, contributes to individual differences in multitasking. In two studies, participants completed a multitasking session in which they monitored four digital clocks running at different rates. In Study 1, we found that individual differences in spatial ability and executive functions were independent predictors of multiple-task performance. In Study 2, we found that individual differences in specific spatial abilities were selectively related to multiple-task performance, as only coordinate spatial processing, but not categorical, predicted multitasking, even beyond executive functioning and numeracy. In both studies, males outperformed females in spatial ability and multitasking and in Study 2 these sex differences generalized to a simulation of everyday multitasking. Menstrual changes moderated the effects on multitasking, in that sex differences in coordinate spatial processing and multitasking were observed between males and females in the luteal phase of the menstrual cycle, but not between males and females at menses. Overall, these findings suggest that multiple-task performance reflects independent contributions of spatial ability and executive functioning. Furthermore, our results support the distinction of categorical versus coordinate spatial processing, and suggest that these two basic relational processes are selectively affected by female sex hormones and differentially effective in transforming and handling temporal patterns as spatial relations in the context of multitasking.

  19. Ligand design for site-selective metal coordination: synthesis of transition-metal complexes with η{sup 6}-coordination of the central ring of anthracene

    Energy Technology Data Exchange (ETDEWEB)

    Karslyan, Eduard E.; Borissova, Alexandra O.; Perekalin, Dmitry S. [Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow (Russian Federation)


    A polycyclic aromatic ligand for site-selective metal coordination was designed by using DFT calculations. The computational prediction was confirmed by experiments: 2,3,6,7-tetramethoxy-9,10-dimethylanthracene initially reacts with [(C{sub 5}H{sub 5})Ru(MeCN){sub 3}]BF{sub 4} to give the kinetic product with a [(C{sub 5}H{sub 5})Ru]{sup +} fragment coordinated at the terminal ring, which is then transformed into the thermodynamic product with coordination through the central ring. These isomeric complexes have markedly different UV/Vis spectra, which was explained by analysis of the frontier orbitals. At the same time, the calculations suggest that electrostatic interactions are mainly responsible for the site selectivity of the coordination. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Key point selection and clustering of swimmer coordination through Sparse Fisher-EM

    CERN Document Server

    Komar, John; Seifert, Ludovic


    To answer the existence of optimal swimmer learning/teaching strategies, this work introduces a two-level clustering in order to analyze temporal dynamics of motor learning in breaststroke swimming. Each level have been performed through Sparse Fisher-EM, a unsupervised framework which can be applied efficiently on large and correlated datasets. The induced sparsity selects key points of the coordination phase without any prior knowledge.

  1. A Perylene-Based Microporous Coordination Polymer Interacts Selectively with Electron-Poor Aromatics. (United States)

    Tran, Ly D; Ma, Jialiu; Wong-Foy, Antek G; Matzger, Adam J


    The design, synthesis, and properties of the new microporous coordination polymer UMCM-310 are described. The unique electronic character of the perylene-based linker enables selective interaction with electron-poor aromatics leading to efficient separation of nitroaromatics. UMCM-310 possesses high surface area and large pore size and thus permits the separation of large organic molecules based on adsorption rather than size exclusion.

  2. Selection of leading industries for coal resource cities based on coupling coordination of industry's technological innovation

    Institute of Scientific and Technical Information of China (English)

    Du Jiming; Yu Bo; Yao Xilong


    Taking the city of Qitaihe is as an example in order to provide practical methods for the selection of leading industries for coal resource cities,this paper establishes the specific operation scheme for selection of leading industries according to the actual situation of coal resource cities based on the theory of coupling coordination together with the coupling coordination for technological innovation.The results show that the degree for coupling coordination of the technological innovation for each alternative industry differentiates with the development of coal resource cities.For example,the average degree of food processing industry from agricultural produce is 0.9.Therefore,coal resource cities should develop some industries related to coal industry,such as coking industry,some chemical and medicines industry and non-metallic mineral products manufacturing,in the near future,however,some industries with greater market and influence potentials and low carbon emissions should be attached much importance to in the future.

  3. Dinuclear ruthenium complexes display loop isomer selectivity to c-MYC DNA G-quadriplex and exhibit anti-tumour activity. (United States)

    Zheng, Chuping; Liu, Yanan; Liu, Ying; Qin, Xiuying; Zhou, Yanhui; Liu, Jie


    G-quadruplex DNA, especially the cellular-myelocytomatosis viral oncogene (c-MYC) is closely associated with cell-cycle regulation, proliferation of tumour cells. In this work, the interaction between the c-MYC and two dinuclear Ru(II) complexes [(bpy)2Ru(bpibp)Ru(bpy)2](ClO4)4 (compound 1) and [(phen)2Ru(bpibp)Ru(phen)2](ClO4)4 (compound 2) have been studied. The data from UV-Visible, PCR-stop and Fluorescence resonance energy transfer (FRET) showed that two complexes can stabilize the structure of G-quadruplex in the c-MYC promoter and targeting the G-quadruplex loop isomers. Interestingly, the complex 2 has a greater effect on the 1:2:1 and 2:1:1 loop isomers while the 1 prefers to the 1:2:1 isomers. The mechanism studies revealed that complexes can induce apoptosis in HepG2 cells by generating ROS metabolites, triggering mitochondrial membrane potential loss and down-regulation of P-Akt (Akt also known as protein kinase B), P-p44/42 MAP kinase protein (P-p44/42), and c-MYC. Taken together, these results suggested that the two dinuclear complexes may both be candidates as anti-tumour agents as they may reduce the c-MYC gene expression. {bpibp: 4, 4'-bis (1, 10-phenanthroline-[5, 6-d] imidazole-2-yl)-biphenyl, bpy: 2,2-bipyridine, phen: 1,10-phenanthroline}. Copyright © 2016. Published by Elsevier Inc.

  4. Solvent and temperature induced switching between structural isomers of Rh(I) phosphinoalkyl thioether (PS) complexes. (United States)

    Wiester, Michael J; Braunschweig, Adam B; Yoo, Hyojong; Mirkin, Chad A


    To develop functional systems based on the weak-link approach (WLA), it is important to understand how solvent and ligand binding strength alter the coordination geometry of complexes formed from this method. A series of phosphinoalkyl thioether (PS) hemilabile ligands with varying electron donating abilities were synthesized and incorporated into homoligated Rh(I)(PS)2Cl complexes to help understand the effects of solvent and ligand binding strength on the preferred coordination modes. The switching between closed and semiopen structural isomers of these Rh(I)(PS)2Cl complexes was studied by variable temperature 31P NMR spectroscopy in different solvent mixtures of CH2Cl2 and tetrahydrofuran (THF) to obtain thermodynamic parameters (DeltaG(o), DeltaH(o), TDeltaS(o), and K(eq)). The isomers differ in the position of the chloride counterion. In the closed isomer, the Cl- anion occupies the outer coordination sphere, while in the semiopen isomer, the Cl- has moved inner sphere and displaced one of the Rh-S bonds. The closed isomer is favored in CH2Cl2 and the semiopen isomer is favored in THF. The preference for either isomer at equilibrium depends on the solvent polarity, based upon the E(T)(N) solvent polarity scale, as was determined from 15 different solvents, with more polar solvents favoring the closed isomer. The isomer preference also depends on the electron donating ability of the group attached to the sulfur of the PS ligand, with electron donating groups favoring the closed isomers and electron withdrawing groups favoring the semiopen isomers. The formation of the semiopen isomer from the closed isomer is entropically favored but enthalpically disfavored under all conditions studied. Elucidation of the principles and environments that determine the equilibrium between the two isomers will aid in the design of functional complexes prepared by the WLA.

  5. A dynamical model of hierarchical selection and coordination in speech planning.

    Directory of Open Access Journals (Sweden)

    Sam Tilsen

    Full Text Available studies of the control of complex sequential movements have dissociated two aspects of movement planning: control over the sequential selection of movement plans, and control over the precise timing of movement execution. This distinction is particularly relevant in the production of speech: utterances contain sequentially ordered words and syllables, but articulatory movements are often executed in a non-sequential, overlapping manner with precisely coordinated relative timing. This study presents a hybrid dynamical model in which competitive activation controls selection of movement plans and coupled oscillatory systems govern coordination. The model departs from previous approaches by ascribing an important role to competitive selection of articulatory plans within a syllable. Numerical simulations show that the model reproduces a variety of speech production phenomena, such as effects of preparation and utterance composition on reaction time, and asymmetries in patterns of articulatory timing associated with onsets and codas. The model furthermore provides a unified understanding of a diverse group of phonetic and phonological phenomena which have not previously been related.

  6. A dynamical model of hierarchical selection and coordination in speech planning. (United States)

    Tilsen, Sam


    studies of the control of complex sequential movements have dissociated two aspects of movement planning: control over the sequential selection of movement plans, and control over the precise timing of movement execution. This distinction is particularly relevant in the production of speech: utterances contain sequentially ordered words and syllables, but articulatory movements are often executed in a non-sequential, overlapping manner with precisely coordinated relative timing. This study presents a hybrid dynamical model in which competitive activation controls selection of movement plans and coupled oscillatory systems govern coordination. The model departs from previous approaches by ascribing an important role to competitive selection of articulatory plans within a syllable. Numerical simulations show that the model reproduces a variety of speech production phenomena, such as effects of preparation and utterance composition on reaction time, and asymmetries in patterns of articulatory timing associated with onsets and codas. The model furthermore provides a unified understanding of a diverse group of phonetic and phonological phenomena which have not previously been related.

  7. Selection of head and whisker coordination strategies during goal-oriented active touch. (United States)

    Schroeder, Joseph B; Ritt, Jason T


    In the rodent whisker system, a key model for neural processing and behavioral choices during active sensing, whisker motion is increasingly recognized as only part of a broader motor repertoire employed by rodents during active touch. In particular, recent studies suggest whisker and head motions are tightly coordinated. However, conditions governing the selection and temporal organization of such coordinated sensing strategies remain poorly understood. We videographically reconstructed head and whisker motions of freely moving mice searching for a randomly located rewarded aperture, focusing on trials in which animals appeared to rapidly "correct" their trajectory under tactile guidance. Mice orienting after unilateral contact repositioned their whiskers similarly to previously reported head-turning asymmetry. However, whisker repositioning preceded head turn onsets and was not bilaterally symmetric. Moreover, mice selectively employed a strategy we term contact maintenance, with whisking modulated to counteract head motion and facilitate repeated contacts on subsequent whisks. Significantly, contact maintenance was not observed following initial contact with an aperture boundary, when the mouse needed to make a large corrective head motion to the front of the aperture, but only following contact by the same whisker field with the opposite aperture boundary, when the mouse needed to precisely align its head with the reward spout. Together these results suggest that mice can select from a diverse range of sensing strategies incorporating both knowledge of the task and whisk-by-whisk sensory information and, moreover, suggest the existence of high level control (not solely reflexive) of sensing motions coordinated between multiple body parts. Copyright © 2016 the American Physiological Society.

  8. Selective organic synthesis through generation and reactivity control of hyper-coordinate metal species. (United States)

    Hiyama, Tamejiro


    This paper is a review of my 40 years of research at Kyoto, Sagamihara, and Yokohama, all based on the generation of hyper-coordinate metal species such as ate complexes and pentacoordinate silicates. The topics are: (i) carbenoid reagents for carbon-carbon bond-forming reactions, (ii) nucleophilic substitution at acetal carbons using aluminate reagents, (iii) preparation of magnesium enolates and its reaction with nitriles, (iv) Cr(II) reagents for reduction of organic halides and highly selective carbon-carbon bond formation, (v) organic synthesis with organosilion reagents/fluoride ions, (vi) cross-coupling reaction of organosilicon compounds, and (vii) silicon-based conjugate addition to alpha,beta-unsaturated carbonyl acceptors.

  9. A two-dimensional coordination compound as a zinc ion selective luminescent probe for biological applications. (United States)

    Dhara, Koushik; Karan, Santanu; Ratha, Jagnyeswar; Roy, Partha; Chandra, Goutam; Manassero, Mario; Mallik, Biswanath; Banerjee, Pradyot


    A 2D coordination compound {[Cu2(HL)(N3)]ClO4}infinity (1; H3L = 2,6-bis(hydroxyethyliminoethyl)-4-methyl phenol) was synthesized and characterized by single-crystal X-ray diffraction to be a polymer in the crystalline state. Each [Cu2(HL)(N3)]+ species is connected to its adjacent unit by a bridging alkoxide oxygen atom of the ligand to form a helical propagation along the crystallographic a axis. The adjacent helical frameworks are connected by a ligand alcoholic oxygen atom along the crystallographic b axis to produce pleated 2D sheets. In solution, 1 dissociates into [Cu2(HL)2(H3L)]2H2O (2); the monomer displays high selectivity for Zn2+ and can be used in HEPES buffer (pH 7.4) as a zinc ion selective luminescent probe for biological application. The system shows a nearly 19-fold Zn2+-selective chelation-enhanced fluorescence response in the working buffer. Application of 2 to cultured living cells (B16F10 mouse melanoma and A375 human melanoma) and rat hippocampal slices was also studied by fluorescence microscopy.

  10. Grip selection for sequential movements in children and adults with and without Developmental Coordination Disorder. (United States)

    Wilmut, Kate; Byrne, Maia


    When generating a movement adults favor grasps which start the body in an uncomfortable position if they end in a comfortable position (the end-state-comfort effect). In contrast, children with Developmental Coordination Disorder (DCD) select grasps which require little initial hand rotation even though they result in an uncomfortable end position. The current study considered grip selection of individuals with DCD when asked to make simple one step movements and when making more complex multi-staged movements. Adults with DCD (N=17, mean age 24:09, SD age=52months) and children with DCD (N=20, mean age 9:00, SD age=20months) and age and gender matched controls rotated a disc so an arrow pointed toward a specific target(s). Task complexity was increased by increasing the number of targets from 1 to 3. Planning for end-state-comfort was seen in all groups albeit to a lesser extent in children versus adults. The children with DCD showed fewer grips for end-state-comfort compared to their peers and this was explained by a propensity to select minimal initial rotation grasps. This result was mirrored in adults with DCD but only for the longest movement sequence. These results suggest some changes in ability from childhood to adulthood in individuals with DCD.

  11. Phase transition equilibrium of terthiophene isomers

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Jose C.S.; Lima, Carlos F.R.A.C.; Rocha, Marisa A.A. [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Gomes, Ligia R. [CIAGEB, Faculdade de Ciencias de Saude Escola Superior de Saude da UFP, Universidade Fernando Pessoa, Rua Carlos da Maia, 296, P-4200-150 Porto (Portugal); REQUIMTE, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Santos, Luis M.N.B.F., E-mail: lbsantos@fc.up.p [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)


    The thermodynamic study of the phase transition (fusion and sublimation) of 2,2':5',2''-terthiophene and 3,2':5',3''-terthiophene is presented. The obtained data is used to evaluate the (solid + liquid) and (solid + gas) phase equilibrium, and draw the phase diagrams of the pure compounds near the triple point coordinates. For each compound the vapour pressures at different temperatures were measured by a combined Knudsen effusion method with a vacuum quartz crystal microbalance. Based on the previous results, the standard molar enthalpies, entropies and Gibbs energies of sublimation were derived at T = 298.15 K. For the two terthiophenes and for 3,3'-bithiophene, the temperature, and the molar enthalpies of fusion were measured in a power compensated differential scanning calorimetry. The relationship between structure and energetics is discussed based on the experimental results, ab initio calculations and previous literature data for 2,2'-bithiophene and 3,3'-bithiophene. The 3,2':5',3''-terthiophene shows a higher solid phase stability than the 2,2':5',2''-terthiophene isomer arising from the higher cohesive energy due to positioning of the sulphur atom in the thiophene ring. The higher phase stability of 3,3'-bithiophene relative to 2,2'-bithiophene isomer is also related to its higher absolute entropy in the solid phase associated with the ring positional degeneracy observed in the crystal structure of this isomer. A significant differentiation in the crystal phase stability between isomers was found.

  12. Selected Coordination Motor Abilities of Students of the University of Physical Education During Survival Training

    Directory of Open Access Journals (Sweden)

    Tomczak Andrzej


    Full Text Available Introduction. Taking up emergency actions when fighting various types of natural disasters requires appropriate psychophysical preparation. Thanks to the development of technique, coordination motor abilities have gained greater importance than physical strength and endurance in such activities. The purpose of the present work was to assess the impact of 36 hours of survival activities and sleep deprivation on selected coordination motor abilities in students of the University of Physical Education. Material and methods. The study involved 12 male students of the University of Physical Education in Warsaw, specialising in “Physical Education in Uniformed Services”. The age of the participants was 21.0 ± 0.74 years, their body height was 179.5 ± 5.6 cm, and their body mass was 74.6 ± 8.0 kg. The assessment was performed based on the following coordination motor ability tests: a test measuring the differentiation of the use of forearm muscle strength, a running motor adjustment test, and a measurement of divided attention. A test involving shooting from a pneumatic gun and a measurement of the maximal force of the forearm were also carried out. Tests and trials were conducted before training (P1, after 24 hours of training (P2, after completing the training - that is after 36 hours of training (P3, and after 12 hours of rest (P4. During the training, the participants completed 12 km on foot, paddled for approximately 6 hours, rowed kayaks for about 4 hours, and performed survival tasks. Results. The analysis of the results of the study of maximal force and the ability to differentiate forearm muscle strength showed that the forearm muscle strength remained at the same level during the entire training. The ability to differentiate forearm muscle strength deteriorated after night training. There were no statistically significant differences in the results of the running motor adjustment tests and in shooting performance between individual

  13. A monofunctional platinum complex coordinated to a rhodium metalloinsertor selectively binds mismatched DNA in the minor groove. (United States)

    Weidmann, Alyson G; Barton, Jacqueline K


    We report the synthesis and characterization of a bimetallic complex derived from a new family of potent and selective metalloinsertors containing an unusual Rh-O axial coordination. This complex incorporates a monofunctional platinum center containing only one labile site for coordination to DNA, rather than two, and coordinates DNA nonclassically through adduct formation in the minor groove. This conjugate displays bifunctional, interdependent binding of mismatched DNA via metalloinsertion at a mismatch as well as covalent platinum binding. DNA sequencing experiments revealed that the preferred site of platinum coordination is not the traditional N7-guanine site in the major groove, but rather N3-adenine in the minor groove. The complex also displays enhanced cytotoxicity in mismatch repair-deficient and mismatch repair-proficient human colorectal carcinoma cell lines compared to the chemotherapeutic cisplatin, and it triggers cell death via an apoptotic pathway, rather than the necrotic pathway induced by rhodium metalloinsertors.

  14. Isomer Energy System Design Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, D


    Isomer energy supplies offer the potential to increase the output power over time to accommodate varying power needs. Other materials with similar energy density (for example isotopic energy sources such as {sup 238}Pu) do not offer the potential to increase power with time. Often the design life of an energy source is significant when compared to the half-life of the isotope. As a result, the conventional isotopic energy supplies operate with significant excess power at start of life to meet the power needs at end-of-life. For example a {sup 238}Pu radioisotope energy supply with a 35-year design life must account for radioactive decay losses of about 25% of the plutonium present at the start of life. This decay loss is significant if the required output power from the device is constant with time. If the required power output from the device increases with time (such as some space applications), significant increases in power supply weight are required to meet design power requirements. Isomer energy supplies offer the potential to increase the output power over time to meet varying power needs, thereby offering a significant advantage over conventional systems. Isomer energy supplies also offer the possibility of being ''turned on'' based on need at a specific time. These characteristics offer distinct advantages to isomer energy supplies. This report examines the basic engineering characteristics of a hypothetical isomer energy supply in order to gain insight into properties of isomers that will make them potentially useful as energy sources in engineered systems. These isomer properties provide a basis for identification of candidate isomers and provide a basis for an isomer search.

  15. Preferential selection of isomer binding from chiral mixtures: alternate binding modes observed for the E and Z isomers of a series of 5-substituted 2,4-diaminofuro[2,3-d]pyrimidines as ternary complexes with NADPH and human dihydrofolate reductase

    Energy Technology Data Exchange (ETDEWEB)

    Cody, Vivian, E-mail: [Structural Biology Department, Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203 (United States); University of Buffalo, 700 Ellicott Street, Buffalo, NY 14203 (United States); Piraino, Jennifer; Pace, Jim [Structural Biology Department, Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203 (United States); Li, Wei; Gangjee, Aleem [Graduate Division, Medicinal Chemistry, Duquesne University, Pittsburgh, PA 15213 (United States); Structural Biology Department, Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203 (United States)


    The structures of six chirally mixed E/Z-isomers of 5-substituted 2,4-diaminofuro[2,3-d]pyrimidines reveals only one isomer is bound in the active site of human DHFR. The configuration of all but one C9-analogue is observed as the E-isomer. The crystal structures of six human dihydrofolate reductase (hDHFR) ternary complexes with NADPH and a series of mixed E/Z isomers of 5-substituted 5-[2-(2-methoxyphenyl)-prop-1-en-1-yl]furo[2,3-d]pyrimidine-2,4-diamines substituted at the C9 position with propyl, isopropyl, cyclopropyl, butyl, isobutyl and sec-butyl (E2–E7, Z3) were determined and the results were compared with the resolved E and Z isomers of the C9-methyl parent compound. The configuration of all of the inhibitors, save one, was observed as the E isomer, in which the binding of the furopyrimidine ring is flipped such that the 4-amino group binds in the 4-oxo site of folate. The Z3 isomer of the C9-isopropyl analog has the normal 2,4-diaminopyrimidine ring binding geometry, with the furo oxygen near Glu30 and the 4-amino group interacting near the cofactor nicotinamide ring. Electron-density maps for these structures revealed the binding of only one isomer to hDHFR, despite the fact that chiral mixtures (E:Z ratios of 2:1, 3:1 and 3:2) of the inhibitors were incubated with hDHFR prior to crystallization. Superposition of the hDHFR complexes with E2 and Z3 shows that the 2′-methoxyphenyl ring of E2 is perpendicular to that of Z3. The most potent inhibitor in this series is the isopropyl analog Z3 and the least potent is the isobutyl analog E6, consistent with data that show that the Z isomer makes the most favorable interactions with the active-site residues. The isobutyl moiety of E6 is observed in two orientations and the resultant steric crowding of the E6 analog is consistent with its weaker activity. The alternative binding modes observed for the furopyrimidine ring in these E/Z isomers suggest that new templates can be designed to probe these binding

  16. Isomer Spectrum of Small Carbon Clusters

    Institute of Scientific and Technical Information of China (English)

    SHENG Yang; LI Peng; NING Xi-Jing


    A theoretical method is developed to find isomers of cluster particles, and the isomer spectrum of carbon clusters Cn (n = 3-44) is obtained. It is found that the isomers of 3-11 atoms are in either mono-ring or line shapes,while the isomers of 12-18 atoms show flat sheet shapes. As cluster size increases, bowl isomers become more (n > 19) until cage isomers dominate the structures (n > 27). Based on the isomer spectrum, results of a previous experiment are interpreted.

  17. Adsorption equilibria of dimethylnaphthalene isomers

    Energy Technology Data Exchange (ETDEWEB)

    Rota, R.; Morbidelli, M. [Politecnico di Milano (Italy). Dipt. di Chimica Fisica Applicata; Rombi, E.; Monaci, R.; Ferino, I.; Solinas, V. [Univ. di Cagliari (Italy). Dipt. di Scienze Chimiche


    Commercial sources of DMNs are the aromatic petroleum fraction of the appropriate boiling range and the coal liquefaction products. Adsorption processes for separating mixtures of dimethylnaphthalene (DMN) isomers are of potential interest for the production of 2,6-DMN. In this work, the adsorption equilibria of liquid mixtures of DMN isomers on zeolites have been investigated experimentally. The separation factors between the various isomers have been found to depend strongly on the composition of the fluid phase. A suitable equilibrium model, based on the adsorbed solution theory, has been developed to describe the multicomponent adsorption equilibria in the entire range of interest. Its performance has been tested using binary and ternary equilibrium data.

  18. Zinc(II) and cadmium(II) coordination polymers containing phenylenediacetate and bis(imidazol-1-ylmethyl)benzene linkers: The effect of ligand isomers on the solid state structures (United States)

    Günay Sezer, Güneş; Zafer Yeşilel, Okan; Şahin, Onur; Burrows, Andrew D.


    This work presents a systematic investigation of the reactions of o-, m- and p-phenylenediacetic acid with Zn(II)/Cd(II) salts in the presence of different semi-rigid o-, m- and p-bis(imidazol-1-ylmethyl)benzene co-ligands. Fourteen new coordination polymers - {[Zn(μ-opda)(μ-mbix)]·0.5H2O}n (1), {[Zn(μ-mpda)(μ-obix)]·H2O}n (2), {[Zn2(μ-mpda)2(μ-mbix)2]·5H2O}n (3), {[Zn(μ-mpda)(μ-mbix)]·2H2O}n (4), {[Zn(μ-mpda)(μ-pbix)]·0.5H2O}n (5), [Zn(μ-ppda)(μ-obix)]n (6), {[Zn(μ-ppda)(μ-mbix)]·0.5H2O}n (7), {[Zn(μ-ppda)(μ-pbix)]·H2O·DMF}n (8), {[Cd(μ-mpda)(μ-obix)1.5]·H2O}n (9), {[Cd(μ-mpda)(μ-obix)]·H2O}n (10), {[Cd(μ-mpda)(μ-mbix)(H2O)]·H2O}n(11), [Cd(μ3-ppda)(μ-obix)]n (12), [Cd(μ3-ppda)(μ-mbix)]n (13) and [Cd(μ3-ppda)(μ-pbix)]n (14) (o/m/ppda=1,2/1,3-/1,4-phenylenediacetate, o/m/pbix=1,2-/1,3-/1,4-bis(imidazol-1-ylmethyl)benzene) - have been prepared and structurally characterized. Two of the complexes were found to possess one-dimensional (1D) structures, eleven complexes were found to be two-dimensional (2D) coordination networks and one of the complexes was found to be a three-dimensional (3D) coordination network. Of the 1D structures, 3 forms nanotubes, whereas in 8 pairs of pbix ligands bridge the zinc(II) centers to generate Zn2(pbix)2 dimers, which in turn are linked together by pairs of ppda linkers to give chains. Compound 5 contains a 4-fold interpenetrated 3D framework. The structure of 10 contains interpenetrated 2D frameworks, leading to a three-dimensional gross structure. The thermal stabilities and luminescent properties for 1-14 are also reported.

  19. Inner and Outer Coordination Shells of Mg(2+) in CorA Selectivity Filter from Molecular Dynamics Simulations. (United States)

    Kitjaruwankul, Sunan; Wapeesittipan, Pattama; Boonamnaj, Panisak; Sompornpisut, Pornthep


    Structural data of CorA Mg(2+) channels show that the five Gly-Met-Asn (GMN) motifs at the periplasmic loop of the pentamer structure form a molecular scaffold serving as a selectivity filter. Unfortunately, knowledge about the cation selectivity of Mg(2+) channels remains limited. Since Mg(2+) in aqueous solution has a strong first hydration shell and apparent second hydration sphere, the coordination structure of Mg(2+) in a CorA selectivity filter is expected to be different from that in bulk water. Hence, this study investigated the hydration structure and ligand coordination of Mg(2+) in a selectivity filter of CorA using molecular dynamics (MD) simulations. The simulations reveal that the inner-shell structure of Mg(2+) in the filter is not significantly different from that in aqueous solution. The major difference is the characteristic structural features of the outer shell. The GMN residues engage indirectly in the interactions with the metal ion as ligands in the second shell of Mg(2+). Loss of hydrogen bonds between inner- and outer-shell waters observed from Mg(2+) in bulk water is mostly compensated by interactions between waters in the first solvation shell and the GMN motif. Some water molecules in the second shell remain in the selectivity filter and become less mobile to support the metal binding. Removal of Mg(2+) from the divalent cation sensor sites of the protein had an impact on the structure and metal binding of the filter. From the results, it can be concluded that the GMN motif enhances the affinity of the metal binding site in the CorA selectivity filter by acting as an outer coordination ligand.

  20. A coordination polymer based magnetic adsorbent material for hemoglobin isolation from human whole blood, highly selective and recoverable (United States)

    Zhang, Xiaoxing; Tan, Jipeng; Xu, Xinxin; Shi, Fanian; Li, Guanglu; Yang, Yiqiao


    A composite material has been obtained successfully through the loading of nanoscale coordination polymer on magnetic Fe3O4@SiO2 core-shell particle. In this composite material, coordination polymer nanoparticles distribute uniformly on Fe3O4@SiO2 and these two components are ;tied; together firmly with chemical bonds. Adsorption experiments suggest this composite material exhibits very excellent selectivity to hemoglobin. But under the same condition, its adsorption to bovine serum albumin can almost be ignored. This selectivity can be attributed to the existence of hydrophobic interactions between coordination polymer nanoparticle and hemoglobin. For composite material, the hemoglobin adsorption process follows Langmuir model perfectly with high speed. The adsorbed hemoglobin can be eluted easily by sodium dodecyl sulfate stripping reagent with structure and biological activity of hemoglobin keeps well. The composite material was also employed to separate hemoglobin from human whole blood, which receives a very satisfactory result. Furthermore, magnetic measurement reveals ferromagnetic character of this composite material with magnetization saturation 3.56 emu g-1 and this guarantees its excellent magnetic separation performance from the treated solution.

  1. Controlling orbital-selective Kondo effects in a single molecule through coordination chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Tsukahara, Noriyuki; Kawai, Maki; Takagi, Noriaki, E-mail: [Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Minamitani, Emi; Kim, Yousoo [RIKEN, 2-1 Hirosawa, Saitama 351-0198 (Japan)


    Iron(II) phthalocyanine (FePc) molecule causes novel Kondo effects derived from the unique electronic structure of multi-spins and multi-orbitals when attached to Au(111). Two unpaired electrons in the d{sub z}{sup 2} and the degenerate dπ orbitals are screened stepwise, resulting in spin and spin+orbital Kondo effects, respectively. We investigated the impact on the Kondo effects of the coordination of CO and NO molecules to the Fe{sup 2+} ion as chemical stimuli by using scanning tunneling microscopy (STM) and density functional theory calculations. The impacts of the two diatomic molecules are different from each other as a result of the different electronic configurations. The coordination of CO converts the spin state from triplet to singlet, and then the Kondo effects completely disappear. In contrast, an unpaired electron survives in the molecular orbital composed of Fe d{sub z}{sup 2} and NO 5σ and 2π* orbitals for the coordination of NO, causing a sharp Kondo resonance. The isotropic magnetic response of the peak indicates the origin is the spin Kondo effect. The diatomic molecules attached to the Fe{sup 2+} ion were easily detached by applying a pulsed voltage at the STM junction. These results demonstrate that the single molecule chemistry enables us to switch and control the spin and the many-body quantum states reversibly.

  2. Anticancer Potencies of Pt(II) - and Pd(II)-linked M2L4 Coordination Capsules with Improved Selectivity. (United States)

    Ahmedova, Anife; Momekova, Denitsa; Yamashina, Masahiro; Shestakova, Pavletta; Momekov, Georgi; Akita, Munetaka; Yoshizawa, Michito


    Pt(II) - and Pd(II)-linked M2 L4 coordination capsules, providing a confined cavity encircled by polyaromatic frameworks, exhibit anticancer activities superior to cisplatin against two types of leukemic cells (HL-60 and SKW-3) and pronounced toxicity against cisplatin-resistant cells (HL-60/CDDP). Notably, the cytotoxic selectivities of the Pt(II) and Pd(II) capsules toward cancerous cells are up to 5.3-fold higher than that of cisplatin, as estimated through the non-malignant/malignant-cells toxicity ratio employing normal kidney cells (HEK-293). In addition, the anticancer activity of the coordination capsules can be easily altered upon encapsulation of organic guest molecules.

  3. Cardiac effects of r-79595 and its isomers (r-80122 and r-80123) in an acute heart-failure model - a new class of cardiotonic agents with highly selective phosphodiesterase-iii inhibitory properties

    NARCIS (Netherlands)



    R 79595 (N-cyclohexyl-N-methyl-2-[[[phenyl (1,2,3,5-tetrahydro-2 oxoimidazo [2,1-b]-quinazolin-7-yl) methylene] amin] oxy] acetamide) and its isomers represent a novel class of compounds with phosphodiesterase (PDE) inhibitory and cardiotonic (positive inotropic) actions. The cardiac effects of this

  4. Patchouli alkohol isomers pogostemon herba predicted virtually

    Directory of Open Access Journals (Sweden)

    Sentot Joko Raharjo


    Full Text Available The aim of our research is predicting the alpha-patchouli alcohol isomer Pogostemon Herba as inhibitors cyclooxygenase (COX-1 and COX-2 isoenzymes. The data for the alpha-patchouli alcohol isomer (CD521903, CD442384, and/or CD6432585 Pogostemon Herba were explored from the pubchem database. Molecular interaction studies with COX-1 and COX-2 from mouse were done using the molecular docking tools Hex 6.12 and LeadIT2 Bisolve. The analysis of the alpha-patchouli alcohol compounds of patchouli oil showed that alpha-Patchouli alcohol (CD521903 binds to COX-1 at active sites including: LEU223B, ASP228B, LEU237B, ARG 332B, TRP 138A, GLU 139A, SER 142A, ASN 143A, and the interaction to COX-2 at active site including: GLN 289B, GLU 290B, ARG 222B, LYS 211B, THR 212B, HIS 214B, ASN 382B, HEM682B, GLN 454B, HIS 386B, TRP 387B, HIS 388B, VAL 274B, GLN 203B, VAL 291B, VAL 295B. The interaction hydrogen bond energy between alpha-patchouli alcohol: (CD521903-COX-1 complexes (-4 kJ/mol and CD521903-COX-2 complexes (-8 kJ/ mol by LeadIT2 Biosolve. This suggests alpha-patchouli alcohol CD521903 as candidate for a selective COX-2 inhibitor. These in silico data need further analyses of biological function activity

  5. Impact of selected family socio-economic factors on coordinational predispositions of children

    Directory of Open Access Journals (Sweden)

    Jarosław Domaradzki


    Full Text Available Introduction: Biological growth of children is genetically determined but there are a lot of factors modifying trends of growth. Among them the most important seems to be parents’ education and number of children in family – socio-economical factors. Factors don’t affect organism individually. Interactions between them can increase or decrease. So the aim of the work was to estimate the influence of socio-economic factors like parents’ education and number of children in family on coordinational traits of children aged 10–11. Material and methods: 199 children aged 10-11 underwent medical examination in 2008 in Polkowice and data collected were used in this study.. Information on parents’ education and number of children was used to divide children into four groups: lower education and 3 or more children in family, lower education and less than 3 children in family, higher education and more than 3 children in family and higher education and less than 3 children in family. Three coordinational traits were measured: short time memory, precision of hand and speed movement of the hand. MANOVA test was used to estimate differences between groups and to check interactions between factors. Results: From among 4 groups of boys, these from the worst socio-economic status of family received the worst results in all three tests. Differences between them and the rest of the groups were statistically significant. Differences between the rest of the groups were not statistically significant. In the girls groups children from families with higher parents’ education received statistically significant better results in test of memory. There were not differences between all 4 groups in precision of the hand test. Girls from family with higher parents’ education and 3 or more children in family received the best results in speed of the hand test. Conclusions: Boys are the gender more eco-sensitive. The family with more than 2 children in family

  6. Biological actions of formoterol isomers. (United States)

    Handley, Dean A; Senanayake, Chris H; Dutczak, William; Benovic, Jeffrey L; Walle, Thomas; Penn, Raymond B; Wilkinson, H Scott; Tanoury, Gerald J; Andersson, Rolf G G; Johansson, Fredrik; Morley, John


    Racemic beta(2) agonists, composed of equal amounts of (R)- and (S)-isomers, can display anomalous actions that compromise their effectiveness as asthma therapies. Loss of efficacy during regular use is characteristic of isoprenaline, albuterol and terbutaline and has in part been attributed to the biological effects of the (S)-isomer. This hypothesis was applied to the (R,R)- and (S,S)-isomers of formoterol. (R,R)-formoterol had 1000-times greater affinity (2.9 nm) to the human beta(2) adrenoceptor than (S,S)-formoterol (3100 nm), with receptor binding modulating intracellular cAMP levels. The minimum lethal intravenous (IV) dose was determined to be 100 mg/kg for (R,R)- and 50 mg/kg for (S,S)-formoterol, suggesting that the toxicity of (S,S)-formoterol may not be related to the binding of beta(2) adrenoceptors. In tissues pretreated with (S,S)-formoterol but not with (R,R)- or racemic formoterol contractions to high concentrations of carbachol were exaggerated. In vivo experiments with sensitized guinea pigs demonstrated that (R,R)-formoterol inhibited both histamine and antigen-induced bronchoconstriction with greater potency than (R,R/S,S)-formoterol while (S,S)-formoterol was ineffective. Metabolic radiolabeling experiments of (R,R)-, (S,S)- or (R,R/S,S)-formoterol with crude human liver phenolsulfotransferase (PST) determined the V(max)/K(m) values to be (0.151), (0.74) and (0.143), respectively. The reciprocal plot illustrates a 2-fold reduction in sulfation rate when (R,R)-formoterol is present as a single isomer. The data presented here suggest that (R,R)-formoterol binds to the beta(2) adrenoceptor and inhibits the contraction of bronchial tissues by spasmogens. However, (S,S)-formoterol exhibits properties inconsistent as an asthma therapeutic and may antagonize the actions of (R,R)-formoterol. Copyright 2002 Elsevier Science Ltd.

  7. Isomers chart; Table des isomeres

    Energy Technology Data Exchange (ETDEWEB)

    Dupont-Gautier, P.; Chantelot, S.; Moisson, N. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The nuclear isomers are nuclides offering the same mass number and the same atomic number, but different energy levels. In the following chart the zero energy ground states are omitted and the metastable isomers, i.e. of non-zero energy, known and of measurable lifetime, are listed. The lower limit of this lifetime was set here to 0.1 x 10{sup -6} s. The various isomers were classified in increasing lifetimes. (authors) [French] Les isomeres nucleaires sont des nucleides presentant le meme nombre de masse et le meme numero atomique, mais des niveaux energetiques differents. Dans la table suivante, on a neglige les etats fondamentaux d'energie nulle et on a recense les isomeres metastables, c'est-a-dire d'energie non nulle, connus et de periode mesurable. La limite inferieure de cette periode a ete fixee ici a 0,1 x 10{sup -6} s. Les differents isomeres ont ete classes par periodes croissantes. (auteurs)

  8. Isomers chart; Table des isomeres

    Energy Technology Data Exchange (ETDEWEB)

    Dupont-Gautier, P.; Chantelot, S.; Moisson, N. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The nuclear isomers are nuclides offering the same mass number and the same atomic number, but different energy levels. In the following chart the zero energy ground states are omitted and the metastable isomers, i.e. of non-zero energy, known and of measurable lifetime, are listed. The lower limit of this lifetime was set here to 0.1 x 10{sup -6} s. The various isomers were classified in increasing lifetimes. (authors) [French] Les isomeres nucleaires sont des nucleides presentant le meme nombre de masse et le meme numero atomique, mais des niveaux energetiques differents. Dans la table suivante, on a neglige les etats fondamentaux d'energie nulle et on a recense les isomeres metastables, c'est-a-dire d'energie non nulle, connus et de periode mesurable. La limite inferieure de cette periode a ete fixee ici a 0,1 x 10{sup -6} s. Les differents isomeres ont ete classes par periodes croissantes. (auteurs)

  9. CO2 selective dynamic two-dimensional Zn(II) coordination polymer. (United States)

    Hwang, In Hong; Bae, Jeong Mi; Hwang, Yong-Kyung; Kim, Ha-Yeong; Kim, Cheal; Huh, Seong; Kim, Sung-Jin; Kim, Youngmee


    A CO2 selective dynamic two-dimensional (2D) MOF system, [Zn(glu)(μ-bpe)]·2H2O (·2H2O) (glu = glutarate, bpe = 1,2-bis(4-pyridyl)ethylene), is prepared. Based on variable temperature PXRD patterns, I·2H2O exhibits a structural transformation of the framework upon desolvation. Various gas sorption analyses at low temperatures reveal that solvent-free I selectively adsorbs CO2 over N2, H2, and CH4. Stepped CO2 isotherms for solvent-free I with a large hysteresis between adsorption and desorption branches at 196 K indicate that I is a dynamic framework. Moreover, I·2H2O shows efficient heterogeneous catalytic reactivity for transesterification of various esters. The catalyst can be recycled multiple times without losing its original activity.

  10. Isomer Energy Source for Space Propulsion Systems (United States)


    Nuclear Thermal Rocket PBR Particle-Bed Reactor SNTP Space Nuclear Thermal Propulsion TIC Triggered Isomer Core TIHE Triggered Isomer in a nuclear thermal rocket (NTR) configuration. This includes study of the current state of triggered isomer research, an investigation of 4... thermal rocket this means that heat from the reactive core must be prevented from raising the temperature of the propellant prior to its release from

  11. High spin isomer beam line at RIKEN

    Energy Technology Data Exchange (ETDEWEB)

    Kishida, T.; Ideguchi, E.; Wu, H.Y. [Institute of Physical and Chemical Research, Saitama (Japan)] [and others


    Nuclear high spin states have been the subject of extensive experimental and theoretical studies. For the production of high spin states, fusion reactions are usually used. The orbital angular momentum brought in the reaction is changed into the nuclear spin of the compound nucleus. However, the maximum induced angular momentum is limited in this mechanism by the maximum impact parameter of the fusion reaction and by the competition with fission reactions. It is, therefore, difficult to populate very high spin states, and as a result, large {gamma}-detector arrays have been developed in order to detect subtle signals from such very high spin states. The use of high spin isomers in the fusion reactions can break this limitation because the high spin isomers have their intrinsic angular momentum, which can bring the additional angular momentum without increasing the excitation energy. There are two methods to use the high spin isomers for secondary reactions: the use of the high spin isomers as a target and that as a beam. A high spin isomer target has already been developed and used for several experiments. But this method has an inevitable shortcoming that only {open_quotes}long-lived{close_quotes} isomers can be used for a target: {sup 178}Hf{sup m2} (16{sup +}) with a half-life of 31 years in the present case. By developing a high spin isomer beam, the authors can utilize various short-lived isomers with a short half-life around 1 {mu}s. The high spin isomer beam line of RIKEN Accelerator Facility is a unique apparatus in the world which provides a high spin isomer as a secondary beam. The combination of fusion-evaporation reaction and inverse kinematics are used to produce high spin isomer beams; in particular, the adoption of `inverse kinematics` is essential to use short-lived isomers as a beam.

  12. Optical absorption spectra of Ag-11 isomers

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Fernandez, E. M.


    The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground-stale confi......The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground...

  13. Highly selective and sensitive detection of metal ions and nitroaromatic compounds by an anionic europium(iii) coordination polymer. (United States)

    Feyisa Bogale, Raji; Ye, Junwei; Sun, Yuan; Sun, Tongxin; Zhang, Siqi; Rauf, Abdul; Hang, Cheng; Tian, Peng; Ning, Guiling


    A luminescent Eu(iii)-based coordination polymer, {[Eu(H2O)5(BTEC)][H(C5H6N2)]·3H2O} () has been synthesized under hydrothermal conditions using 1,2,4,5-benzenetetracarboxylic acid (H4BTEC) as a linker. Compound possesses an anionic zig-zag chain constructed from the BTEC ligands and [EuO4(H2O)5] nodes. The protonated 4-aminopyridine groups as guests are located between chains. exhibits the characteristic sharp emission bands of Eu(3+) at 578, 593, 615, 652 and 693 nm upon excitation at 290 nm. The strong emission of could be quenched effectively by trace amounts of Fe(3+) ions even in the presence of other metal ions including Al(3+), Ca(2+), Cd(2+), Co(2+), Cr(3+), Cu(2+), Fe(2+), K(+), Mg(2+), Mn(2+), Pd(2+) and Zn(2+). Similarly, also exhibits superior selectivity and sensitivity towards 4-nitrophenol (4-NP) compared with other competing interfering analytes, such as 2,4,6-trinitrophenol, 2,6-dinitrotolune, 4-nitrotoluene, nitrobenzene, 1,3-dinitrobenzene, o-xylene, nitromethane, nitropropane, phenol, 4-bromophenol and bromobenzene, through a fluorescence quenching mechanism. The possible fluorescence quenching mechanisms are discussed. Moreover, could be used as a visual fluorescent test paper for selectively detecting trace amounts of Fe(3+) and 4-NP.

  14. On the calculation of Mossbauer isomer shift

    NARCIS (Netherlands)

    Filatov, Michael


    A quantum chemical computational scheme for the calculation of isomer shift in Mossbauer spectroscopy is suggested. Within the described scheme, the isomer shift is treated as a derivative of the total electronic energy with respect to the radius of a finite nucleus. The explicit use of a finite nuc

  15. A Zn(II) coordination polymer and its photocycloaddition product: syntheses, structures, selective luminescence sensing of iron(III) ions and selective absorption of dyes. (United States)

    Hu, Fei-long; Shi, Yi-Xiang; Chen, Huan-Huan; Lang, Jian-Ping


    One coordination polymer [Zn2(L)2(bpe)2(H2O)2] (1) (L = 4,4'-((1,2-phenylenebis(methylene))bis(oxy))dibenzoic acid; bpe = (E)-1,2-di(pyridin-4-yl)ethene) was prepared and structurally determined. Compound 1 has a chain structure in which its pair of bpe ligands is arranged in a head-to-tail manner with their C=C bonds being close enough for a [2 + 2] cycloaddition reaction. Upon exposure to UV light, compound 1 undergoes a single-crystal-to-single-crystal (SCSC) [2 + 2] photodimerization to generate one 2D coordination polymer [Zn(L)(rctt-tpcb)0.5(H2O)] (1a) (rctt (regio cis, trans, trans)-tpcb = tetrakis(4-pyridyl)cyclobutane). The tpcb ligands in the crystals of 1a show an intriguing in situ thermal isomerisation. The nanospheres of 1 can be obtained by recrystallization in DMSO/alcohol. The nanospheres of 1a can also be readily produced from the corresponding nanospheres of 1 by the photocyclodimerization method. Compared with those of 1a, the nanospheres of 1 display highly selective sensing of Fe(3+) ions over mixed metal ions through fluorescence quenching. Moreover, the nanospheres of 1a can rapidly adsorb CR (congo red), MB (methylene blue) or RhB (rhodamine B) over MO (methyl orange) from aqueous solutions. This work offers a new photoinduced post-synthetic method for the synthesis of multifunctional MOFs, which show luminescence sensing of Fe(3+) ions and dye adsorption properties.

  16. Highly selective CO2 adsorption accompanied with low-energy regeneration in a two-dimensional Cu(II) porous coordination polymer with inorganic fluorinated PF6(-) anions. (United States)

    Noro, Shin-ichiro; Hijikata, Yuh; Inukai, Munehiro; Fukushima, Tomohiro; Horike, Satoshi; Higuchi, Masakazu; Kitagawa, Susumu; Akutagawa, Tomoyuki; Nakamura, Takayoshi


    High selectivity and low-energy regeneration for adsorption of CO(2) gas were achieved concurrently in a two-dimensional Cu(II) porous coordination polymer, [Cu(PF(6))(2)(4,4'-bpy)(2)](n) (4,4'-bpy = 4,4'-bipyridine), containing inorganic fluorinated PF(6)(-) anions that can act as moderate interaction sites for CO(2) molecules.

  17. [Wisconsin Administrative Practice Scale: Special Education. A Survey of Selected Administrative Practices Used in the Coordination of Diagnostic Units for Handicapped Children. Test and Manual.]. (United States)

    Lietz, Jeremy Jon

    The Wisconsin Administrative Practice Scale: Special Education (WAPS) is a self-administering survey instrument designed to measure implementation of 162 selected administrative practices and policies used to coordinate diagnostic units for handicapped children. One hundred thirty-five items are grouped into seven subscales each consisting of…

  18. Spectral identification of fullerene C82 isomers (United States)

    Gao, Bin; Liu, Lei; Wang, ChunRu; Wu, ZiYu; Luo, Yi


    Ultraviolet photoelectron spectra (UPS) of C82 isomers have been calculated using hybrid density functional theory in combination with the Gelius model [Proceedings of the International Conference on Electron spectroscopy, edited by D. A. Shirley (North-Holland, Amsterdam, 1972), p. 311; J. Electron Spectrosc. Relat. Phenom. 5, 985 (1974)]. The calculated UPS spectra are found to be isomer dependent and in good agreement with the experimental counterparts. Near-edge x-ray absorption fine structure (NEXAFS), x-ray photoelectron spectroscopy (XPS), x-ray emission spectroscopy, and the resonant inelastic x-ray scattering (RIXS) spectra of three important isomers [3(C2), 6(Cs), and 9(C2v)] have also been simulated. Strong isomer dependence has also been found for NEXAFS, XPS, and RIXS spectra.

  19. Conjugated linoleic acid isomers and cancer. (United States)

    Kelley, Nirvair S; Hubbard, Neil E; Erickson, Kent L


    We reviewed the literature regarding the effects of conjugated linoleic acid (CLA) preparations enriched in specific isomers, cis9, trans11-CLA (c9, t11-CLA) or trans10, cis12-CLA (t10, c12-CLA), on tumorigenesis in vivo and growth of tumor cell lines in vitro. We also examined the potential mechanisms by which CLA isomers may alter the incidence of cancer. We found no published reports that examined the effects of purified CLA isomers on human cancer in vivo. Incidence of rat mammary tumors induced by methylnitrosourea was decreased by c9, t11-CLA in all studies and by t10, c12-CLA in just a few that included it. Those 2 isomers decreased the incidence of forestomach tumors induced by benzo (a) pyrene in mice. Both isomers reduced breast and forestomach tumorigenesis. The c9, t11-CLA isomer did not affect the development of spontaneous tumors of the intestine or mammary gland, whereas t10, c12-CLA increased development of genetically induced mammary and intestinal tumors. In vitro, t10, c12-CLA inhibited the growth of mammary, colon, colorectal, gastric, prostate, and hepatoma cell lines. These 2 CLA isomers may regulate tumor growth through different mechanisms, because they have markedly different effects on lipid metabolism and regulation of oncogenes. In addition, c9, t11-CLA inhibited the cyclooxygenase-2 pathway and t10, c12-CLA inhibited the lipooxygenase pathway. The t10, c12-CLA isomer induced the expression of apoptotic genes, whereas c9, t11-CLA did not increase apoptosis in most of the studies that assessed it. Several minor isomers including t9, t11-CLA; c11, t13-CLA; c9, c11-CLA; and t7, c11-CLA were more effective than c9, t11-CLA or t10, c12-CLA in inhibiting cell growth in vitro. Additional studies with purified isomers are needed to establish the health benefit and risk ratios of each isomer in humans.

  20. Facile synthesis of 2D Zn(II) coordination polymer and its crystal structure, selective removal of methylene blue and molecular simulations (United States)

    Sezer, Güneş Günay; Yeşilel, Okan Zafer; Şahin, Onur; Arslanoğlu, Hasan; Erucar, İlknur


    A new coordination polymer {[Zn(μ3-ppda)(H2O)(μ-bpa)Zn(μ-ppda)(μ-bpa)]·4H2O}n (1) (ppda = 1,4-phenylenediacetate, bpa = 1,2-bis(4-pyridyl)ethane) has been synthesized by microwave-assisted reaction and characterized by elemental analysis, IR spectroscopy, single-crystal and powder X-ray diffractions. The asymmetric unit of 1 consists of two Zn(II) ions, two bpa ligands, two ppda ligands, one coordinated and four non-coordinated water molecules. In 1, ppda2- anions are linked the adjacent Zn(II) centers to generate 1D double-stranded chains. These chains are connected into 2D sheets by the bridging bpa ligands. Atomically detailed modeling was performed to compute single and binary component adsorption isotherms of H2, CO2, CH4 and N2 in complex 1. Results showed that 1 exhibits a high adsorption selectivity towards CO2 due to its high affinity for CO2. Results of this study will be helpful to guide the microwave-assisted reaction of coordination polymers to design promising adsorbents for gas storage and gas separation applications. The luminescent property of 1 and the selective removal of dyes in 1 have been also discussed. Results showed that 1 can be a potential candidate for luminescence applications and can selectively adsorb methylene blue (MB) dye molecules.

  1. Separation of C6-Olefin Isomers in Reactive Extractants

    Institute of Scientific and Technical Information of China (English)

    SONG Fengxia; YU Yanmei; CHEN Jian


    Chemical complexation,in which certain metal ions (especially Ag+ and Cu+) reversibly and selectively complex olefin isomers,was used to separate 1-hexene from a mixture of intemal hexenes as an attractive alternative to traditional distillation.Several potential reactive extractants were investigated for their selectivity of both 1-hexene to 2-hexene and 1-hexene to 3-hexene.With 3 mol/L AgNO3-N-methyl-pyrrolidone (NMP) solution as extractant,the selectivity of 1-hexene to 3-hexane was increased to about 2.0 and the selectivity of 1-hexene to 2-hexene reached 1.5.Both the raffinate phase and the extracted phase were analyzed using a gas chromatograph equipped with a flame ionization detector and a 50-m capillary column.The experimental results show that the silver nitrate NMP solution has the better selectivity than other reactive extractions.

  2. Shape-, size-, and functional group-selective binding of small organic guests in a paramagnetic coordination cage. (United States)

    Turega, Simon; Whitehead, Martina; Hall, Benjamin R; Meijer, Anthony J H M; Hunter, Christopher A; Ward, Michael D


    The host-guest chemistry of the octanuclear cubic coordination cage [Co(8)L(12)](16+) (where L is a bridging ligand containing two chelating pyrazolyl-pyridine units connected to a central naphthalene-1,5-diyl spacer via methylene "hinges") has been investigated in detail by (1)H NMR spectroscopy. The cage encloses a cavity of volume of ca. 400 Å(3), which is accessible through 4 Å diameter portals in the centers of the cube faces. The paramagnetism of the cage eliminates overlap of NMR signals by dispersing them over a range of ca. 200 ppm, making changes of specific signals easy to observe, and also results in large complexation-induced shifts of bound guests. The cage, in CD(3)CN solution, acts as a remarkably size- and shape-selective host for small organic guests such as coumarin (K = 78 M(-1)) and other bicyclic molecules of comparable size and shape such as isoquinoline-N-oxide (K = 2100 M(-1)). Binding arises from two independent recognition elements, which have been separately quantified. These are (i) a polar component arising from interaction of the H-bond accepting O atom of the guest with a convergent group of CH protons inside the cavity that lie close to a fac tris-chelate metal center and are therefore in a region of high electrostatic potential; and (ii) an additional component arising from the second aromatic ring (aromatic/van der Waals interactions with the interior surface of the cage and/or solvophobic interactions). The strength of the first component varies linearly with the H-bond-accepting ability of the guest; the second component is fixed at approximately 10 kJ mol(-1). We have also used (1)H-(1)H exchange spectroscopy (EXSY) experiments to analyze semiquantitatively two distinct dynamic processes, viz. movement of the guest into and out of the cavity and tumbling of the guest inside the host cavity. Depending on the size of the guest and the position of substituents, the rates of these processes can vary substantially, and the rates

  3. Fixed-bed adsorption separation of xylene isomers over sio2/silicallite-1 core-shell adsorbents

    KAUST Repository

    Khan, Easir A.


    SiO2/Silicalite-1 core-shell material has been demonstrated as potential shape selective adsorbent in gas phase separation of p-xylene from a mixture of p/o-xylene isomers. The core-shell composite comprised of large silica core and thin polycrystalline silicalite-1 shell which was synthesized via a self-assembly of silicalite-1 nanocrystals on core silica surface followed by a secondary seeded growth method. The core materials, SiO2 used in this study has mesoporosity with an average pore diameter of 60Å and hence offers no shape selectivity for xylene isomers. However, the shell, silicalite-1 contains rigid pore structures and preferentially adsorbs p-xylene from their isomers mixtures. A series of adsorption fixed bed breakthrough adsorption/desorption experiment was performed to obtain the equilibrium isotherms and adsorption isotherm parameters of xylene isomers. The equilibrium isotherms of xylene isomers follow the Langmuir\\'s model. A chromatographic adsorption model has been used to describe the fixed-bed breakthrough profiles of xylene isomers. The model has successfully predicted the responses of the binary mixtures of p/o-xylene isomers. The SiO2/silicalite-1 core-shell adsorbents have shown para-selectivity as high as 15. © Bangladesh Uni. of Engg. & Tech.

  4. High-harmonic spectroscopy of molecular isomers

    Energy Technology Data Exchange (ETDEWEB)

    Wong, M. C. H.; Brichta, J.-P.; Bhardwaj, V. R. [Department of Physics, University of Ottawa, 150 Louis-Pasteur, Ottawa, Ontario, K1N 6N5 (Canada); Spanner, M.; Patchkovskii, S. [National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6 (Canada)


    We demonstrate that high-order-harmonic generation (HHG) spectroscopy can be used to probe stereoisomers of randomly oriented 1,2-dichloroethylene (C{sub 2}H{sub 2}Cl{sub 2}) and 2-butene (C{sub 4}H{sub 8}). The high-harmonic spectra of these isomers are distinguishable over a range of laser intensities and wavelengths. Time-dependent numerical calculations of angle-dependent ionization yields for 1,2-dichloroethylene suggest that the harmonic spectra of molecular isomers reflect differences in their strong-field ionization. The subcycle ionization yields for the cis isomer are an order of magnitude higher than those for the trans isomer. The sensitivity in discrimination of the harmonic spectra of cis- and trans- isomers is greater than 8 and 5 for 1,2-dichloroethylene and 2-butene, respectively. We show that HHG spectroscopy cannot differentiate the harmonic spectra of the two enantiomers of the chiral molecule propylene oxide (C{sub 3}H{sub 6}O).

  5. Aromatic Character of All Possible C36H2 Isomers

    Institute of Scientific and Technical Information of China (English)

    Ablikim Kerim


    The stability of C36H2 isomers and selection rules for choosing position in addition reactions based on symmetrical C36(D6h and D2d) fullerene have been studied by means of Aihara's topological resonance energy (TRE) and bond resonance energy (BRE) methods. The relation between the addition pattern and BREs is established, showing high antiaromatic bonds are preferred for addition. These results show that TRE and BRE methods can be used to predict and interpret addition sites for these systems.

  6. Cis and Trans Isomers of Cycloalkenes (United States)

    Barrows, Susan E.; Eberlein, Thomas H.


    As a rule, a trans disubstituted alkene is more stable than the corresponding cis isomer. For cycloalkenes of fewer than eleven members, cis isomers are more stable than their trans counterparts. Although this exception to the normal rule is occasionally noted in beginning organic chemistry textbooks, it is often done without a careful analysis of the reasons behind it. The purpose of this article is to provide that analysis. In order for a cycloalkene to accommodate a trans double bond one or more of the following nonideal geometries must occur: a twisted π bond; pyramidal sp 2 -carbon atoms; nonideal sp 3 bond angles; or longer than normal C C single and double bonds. This article provides a list of experimentally determined relative energies of the cis and trans isomers within the series cycloheptene cycloundecene, along with computationally derived energies at several levels of theory. It also examines the geometric distortions through which cycloalkenes relieve the strain introduced by a trans double bond.

  7. A Database of Transition-Metal-Coordinated Peptide Cross-Sections: Selective Interaction with Specific Amino Acid Residues (United States)

    Dilger, Jonathan M.; Glover, Matthew S.; Clemmer, David E.


    Ion mobility mass spectrometry (IMS-MS) techniques were used to generate a database of 2288 collision cross sections of transition-metal-coordinated tryptic peptide ions. This database consists of cross sections for 1253 [Pep + X]2+ and 1035 [Pep + X + H]3+, where X2+ corresponds to Mn2+, Co2+, Ni2+, Cu2+, or Zn2+. This number of measurements enables the extraction of structural trends for transition-metal-coordinated peptide ions. The range of structures and changes in collision cross sections for X2+-coordinated species (compared with protonated species of the same charge state) is similar to Mg2+-coordinated species. This suggests that the structures are largely determined by similarities in cation size with differences among the cross section distributions presumably caused by X2+ interactions with specific functional groups offered by the residue R-groups or the peptide backbone. Cross section contributions for individual residues upon X2+ solvation are assessed with the derivation of intrinsic size parameters (ISPs). The comparison of the [Pep + X]2+ ISPs with those previously reported for [Pep + Mg]2+ ions displays a lower contribution to the cross section for His, carboxyamidomethylated Cys, and Met, and is consistent with specific metal-residue interactions identified within protein X-ray crystallography databases.

  8. Analysis of Heme oxygenase isomers in rat

    Institute of Scientific and Technical Information of China (English)

    Yun-ZhuLi; Wen-JunCui; Xue-HongZhang; Qing-XiangShen; JianWang; She


    AIM:To purify and identify heme oxygenase(HO) isomers which exist in rat liver,spleen and brain treated with hematin and phenylhydrazine and in untrated rat liver and to investigate the characteristics of HO isomers,to isolate and confirm the rat HO-1 cDNA that actually encodes HO-1 by expressing cDNA in monkey Kidney cells(COS-1 cells),to prepare the rat heme oxygenase-1(HO-1)mutant and to detect inhibition of HO-1 mutated enzyme.

  9. Two Novel Isomers of HPS3 System

    Institute of Scientific and Technical Information of China (English)

    Hai Tao YU; Ming Xia LI; Yu Juan CHI; Fu Long YUANG; Hong Gang FU; Jia Zhong SUN


    Two new isomers of HPS3 system, HP(S)S2 and HSSPS, are predicted by means of B3LYP method with 6-311++G(3df,3pd) basis set. The two isomers can isomerize into thermodynamically the most stable species HSPS2, which have been experimentally identified, with relatively higher reaction barriers. In view of their higher thermodynamical and kinetic stability and the experimental observation for HP(O)O2 and HOOPO in previous study, we can reasonably believe that the two species can be spectrosymmetrically characterized in future experiments.

  10. An Assessment of Nuclear Isomers as an Energy Storage Medium

    Energy Technology Data Exchange (ETDEWEB)

    Hartouni, E P


    Nuclear Isomers have been suggested as a potential high energy density medium that might be used to store energy. This talk assesses the state of the science supporting key elements of using nuclear isomers in energy storage applications. The focus is on the nuclear isomer {sup 178m2}Hf which has been most widely suggested for energy storage applications. However, the science issues apply to all nuclear isomer. The assessment addresses the production of the nuclear isomer, and inducing the release of the isomer. Also discussed are novel speculations on photon and/or neutron chain reactions, both as a 'pure' material as well as mixed with other materials.

  11. Solvent-mediated crystal-to-crystal interconversion between discrete lanthanide complexes and one-dimensional coordination polymers and selective sensing for small molecules. (United States)

    Wu, Jin-Ji; Ye, Yu-Xin; Qiu, Ying-Yu; Qiao, Zheng-Ping; Cao, Man-Li; Ye, Bao-Hui


    Two isostructural 1D coordination polymers {[Ln(OAc)2(H2O)(OBPT)]·3H2O}n (HOBPT = 4,6-bis(2-pyridyl)-1,3,5-triazin-2-ol, Ln = Eu(3+), 1; Tb(3+), 3) and two discrete complexes [Ln(OAc)2(DMF)2(OBPT)] (Ln = Eu(3+), 2; Tb(3+), 4) have been synthesized in H2O-MeOH or DMF solvents, respectively. Their structures were identified by powder X-ray diffraction. Single-crystal X-ray studies for complexes 1 and 2 revealed that the coordination geometries of the Eu(3+) ions are similar and can be described as a distorted tricapped trigonal prism with six oxygen atoms and three nitrogen atoms. The difference between them is that one aqua ligand and one oxygen atom from the OBPT ligand complete the coordination sphere in complex 1, whereas two DMF molecules complete the coordination sphere in complex 2. Interestingly, the solvent-mediated, reversible crystal-to-crystal transformation between them was achieved by immersing the crystalline samples in the corresponding solvent (H2O or DMF) or by exposing them to solvent vapor. Complex 1 shows a highly selective luminescence enhancement in response to DMF in comparison to that observed in response to other examined solvents such as acetone, ethyl acetate, ethanol, acetonitrile, methanol, and THF.

  12. 'Melatonin isomer' in wine is not an isomer of the melatonin but tryptophan-ethylester. (United States)

    Gardana, Claudio; Iriti, Marcello; Stuknytė, Milda; De Noni, Ivano; Simonetti, Paolo


    Melatonin is a neurohormone, chronobiotic, and antioxidant compound found in wine and deriving directly from grapes and/or synthesized by yeast during alcoholic fermentation. In addition, a melatonin isomer has been detected in different foods, wine among them. The special interest for melatonin isomer related to the fact that it was found in greater quantities than melatonin and probably shares some of its biological properties. Despite this, its chemical structure has not yet been defined; although some researchers hypothesize, it could be melatonin with the ethylacetamide group shifted into position N1. Thus, the aim of our study was to identify the structures of the melatonin isomer. For this purpose, melatonin and melatonin isomer in Syrah wine were separated chromatographically by a sub-2 μm particle column and detected by tandem mass spectrometry. The sample was then purified and concentrated by solid-phase extraction, hydrolyzed with alkali or esterase, and substrates and products quantified by UPLC-MS/MS. Moreover, melatonin, melatonin isomer, and their product ions were evaluated by high-resolution mass spectrometry. The amount of melatonin isomer and melatonin in the wine was 84 ± 4 and 3 ± 0 ng/mL, respectively. In the solutions, containing diluted alkali or esterase, melatonin isomer was hydrolyzed in about 8 min. Correspondingly, tryptophan was detected, and its amount increased and reached the maximum concentration in about 8 min. Melatonin concentration was not affected by diluted alkali or esterase. The fragmentation pattern of melatonin isomer was different from that of melatonin but comparable to that of tryptophan-ethylester. Finally, the so-called melatonin isomer identity was verified by cochromatography with authentic standard of tryptophan-ethylester. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Nuclear spins of the isomers /sup 191m-185m/Hg determined by on-line quantum-beat spectroscopy

    CERN Document Server

    Kremmling, H; Fischer, H G; Kluge, H J; Kühl, T; Schüssler, H A


    The nuclear spins of the very neutron-deficient /sup 191m-185m/Hg isomers were measured on line at the mass separator ISOLIDE at CERN using pulsed-laser excitation and observation of the time-resolved quantum beats from selected hyperfine-structure states. The spins of these isomers are with I=13/2 equal to those of the long-lived isomers /sup 199m-193m/Hg already known. The persistence of this spin value for eight isomers is explained by the model of rotation-aligned coupling. (12 refs).

  14. A new isomer in {sup 125}La

    Energy Technology Data Exchange (ETDEWEB)

    Canchel, G. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire]|[Department of Physics, Accelerator Laboratory, University of Jyvaeskylae, P.O. Box 35, FIN-40351 Jyvaeskylae (Finland); Beraud, R.; Chabanat, E.; Emsallem, A.; Redon, N. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Dendooven, P.; Huikari, J.; Jokinen, A.; Kolhinen, V.; Lhersonneau, G.; Oinonen, M.; Nieminen, A.; Penttilae, H.; Peraejaervi, K.; Wang, J.C.; Aeystoe, J. [Department of Physics, Accelerator Laboratory, University of Jyvaeskylae, P.O. Box 35, FIN-40351 Jyvaeskylae (Finland)


    Levels in {sup 125}La have been studied via {beta}{sup +}/EC decay of on-line mass-separated {sup 125}Ce using the HIGISOL technique. A new (390{+-}40) ms isomer is definitely attributed to {sup 125}La by conversion electron measurements of the 107 keV E3 isomeric transition. (orig.) With 2 figs., 1 tab., 11 refs.

  15. Organometallic chemistry: Heavyweight isomer brings stability (United States)

    Scheschkewitz, David


    Due to its high reactivity, vinylidene -- the sole 'electron-precise' isomer of acetylene -- is only known to exist in the gas phase. Now, a stable base-free digermanium version of a vinylidene has been isolated by the clever use of suitable substituents.

  16. Always-optimally-coordinated candidate selection algorithm for peer-to-peer files sharing system in mobile self-organized networks

    Institute of Scientific and Technical Information of China (English)

    Li Xi; Ji Hong; Zheng Ruiming; Li Ting


    In order to improve the performance of peer-to-peer files sharing system under mobile distributed environments, a novel always-optimally-coordinated (AOC) criterion and corresponding candidate selection algorithm are proposed in this paper. Compared with the traditional min-hops criterion, the new approach introduces a fuzzy knowledge combination theory to investigate several important factors that influence files transfer success rate and efficiency. Whereas the min-hops based protocols only ask the nearest candidate peer for desired files, the selection algorithm based on AOC comprehensively considers users' preference and network requirements with flexible balancing rules. Furthermore, its advantage also expresses in the independence of specified resource discovering protocols, allowing for scalability. The simulation results show that when using the AOC based peer selection algorithm, system performance is much better than the min-hops scheme, with files successful transfer rate improved more than 50% and transfer time reduced at least 20%.

  17. Isomer separation and measurement of nuclear moments with the ISOLDE RILIS

    Energy Technology Data Exchange (ETDEWEB)

    Koester, U.; Catherall, R. [ISOLDE, CERN (Switzerland); Fedoseyev, V.N. [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation); Franchoo, S. [K.U. Leuven, Instituut voor Kern en Stralingsfysica (Belgium); Georg, U. [ISOLDE, CERN (Switzerland); Huyse, M.; Kruglov, K. [K.U. Leuven, Instituut voor Kern en Stralingsfysica (Belgium); Lettry, J. [ISOLDE, CERN (Switzerland); Mishin, V.I. [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation); Oinonen, M.; Ravn, H. [ISOLDE, CERN (Switzerland); Seliverstov, M.D. [St. Petersburg Nuclear Physics Institute (Russian Federation); Simon, H. [ISOLDE, CERN (Switzerland); Van Duppen, P.; Van Roosbroeck, J.; Weissman, L. [K.U. Leuven, Instituut voor Kern en Stralingsfysica (Belgium)


    Short-lived radioisotopes are element selectively ionized by the resonance ionization laser ion source (RILIS) of the on-line isotope separator ISOLDE (CERN). The relative production of low and high spin isomers can be significantly changed when a narrow-bandwidth laser is used to scan through the atomic hyperfine structure. This allows the assignment of gamma ray transitions to the decay of the individual isomers. Moreover, the measurement of the hyperfine splitting provides a very sensitive method for the determination of magnetic moments of exotic isotopes. The technical developments are discussed for the example of copper.

  18. Selective Synthesis of Molecular Borromean Rings: Engineering of Supramolecular Topology via Coordination-Driven Self-Assembly. (United States)

    Kim, Taegeun; Singh, Nem; Oh, Jihun; Kim, Eun-Hee; Jung, Jaehoon; Kim, Hyunuk; Chi, Ki-Whan


    Molecular Borromean rings (BRs) is one of the rare topology among interlocked molecules. Template-free synthesis of BRs via coordination-driven self-assembly of tetracene-based Ru(II) acceptor and ditopic pyridyl donors is reported. NMR and single-crystal XRD analysis observed sequential transformation of a fully characterized monomeric rectangle to molecular BRs and vice versa. Crystal structure of BRs revealed that the particular topology was enforced by the appropriate geometry of the metallacycle and multiple parallel-displaced π-π interactions between the donor and tetracene moiety of the acceptor. Computational studies based on density functional theory also supported the formation of BRs through dispersive intermolecular interactions in solution.

  19. Characterizing traits of coordination

    NARCIS (Netherlands)

    Poss, R.


    How can one recognize coordination languages and technologies? As this report shows, the common approach that contrasts coordination with computation is intellectually unsound: depending on the selected understanding of the word "computation", it either captures too many or too few programming

  20. Modelling Study of Interstellar Ethanimine Isomers (United States)

    Quan, Donghui; Herbst, Eric; Corby, Joanna F.; Durr, Allison; Hassel, George


    Ethanimine (CH3CHNH) , including both the E- and Z- isomers, were detected towards the star-forming region Sgr B2(N) using the GBT PRIMOS data (Loomis et al 2013), and were recently imaged by the ACTA (Corby et al. 2015). These aldimines can serve as precursors of biological molecules such as amino acids thus are considered prebiotic molecules in interstellar medium. In this study, we present chemical simulations of ethanimine with various physical conditions. From models for Sgr B2(N) and environs, calculated ethanimine abundances show reasonable agreement with observed values, while the translucent cloud models yield much lower abundances. These results agree with locations suggested by observations that ethanimine isomers were detected in the foreground of the shells of the hot core.

  1. A thirty second isomer in Hf-171

    NARCIS (Netherlands)

    Campbell, P; Billowes, J; Cochrane, ECA; Cooke, JL; Cooper, TG; Dendooven, P; Evans, DE; Grant, IS; Griffith, JAR; Honkanen, A; Huhta, M; Oinonen, M; Pearson, MR; Penttila, H; Persson, B.L.; Richardson, DS; Tungate, G; Wheeler, PD; Zybert, L; Aysto, J


    An isomer has been detected in Hf-171 with a half-life of T-1/2 = 29.5(9) s. The state was populated in the Yb-170(alpha,3n)Hf-171m reaction at a beam energy of E-alpha = 50 MeV in an on-line ion guide isotope separator. The isomeric Hf-17lm(+) beam was extracted from the ion guide, mass-analysed an

  2. Supramolecular networking of macrocycles based on exo-coordination: from discrete to continuous frameworks. (United States)

    Park, Sunhong; Lee, So Young; Park, Ki-Min; Lee, Shim Sung


    achieve in these networked macrocycles are one to three dimensional coordination polymers based on homo- and heteronuclear metal systems. Using crystal engineering methods, we have also investigated variation in the donors, interdonor distances, ligand isomer structures, and the effect of counter anions on the chemical and physical properties of the products. Understanding the relationship between structure and function in these exo-coordination products is an important step in the design of these new supramolecules for practical applications. We investigated the photophysical properties of the exocyclic complexes and a chromogenic macrocycle, which exhibited cation-selective and anion-controlled color change depending on an exo- or endo- ligand binding mode. Overall, we suggest that the exocyclic coordination behavior provides a versatile strategy for the preparation of new molecular networks and materials.

  3. Selenium-platinum coordination compounds as novel anticancer drugs: selectively killing cancer cells via a reactive oxygen species (ROS)-mediated apoptosis route. (United States)

    Zeng, Lingwu; Li, Yang; Li, Tianyu; Cao, Wei; Yi, Yu; Geng, Weijia; Sun, Zhiwei; Xu, Huaping


    We report the preparation of selenium-containing platinum-based anticancer drug EG-Se/Pt. EG-Se/Pt was obtained from the coordination of selenium-containing molecules (EG-Se) with cisplatin (CDDP). The structure of EG-Se/Pt was characterized by (1) H and (77) Se NMR spectroscopy, XPS, ESI-MS, and MALDI-TOF. In aqueous solution, EG-Se/Pt self-assembles to form spherical aggregates. EG-Se/Pt shows enhanced stability against dilution and high salt concentration compared with EG-Se. EG-Se/Pt induces cell apoptosis via reactive oxygen species (ROS), which leads to high selectivity between cancer cells and normal cells in cytotoxicity assays. More importantly, EG-Se/Pt effectively inhibits tumor growth in vivo in tumor-bearing mice. It is anticipated that tuning the ROS level through the assembly of selenium-containing molecules can be a general method to realize anticancer selectivity.

  4. Target-Triggered Switching on and off the Luminescence of Lanthanide Coordination Polymer Nanoparticles for Selective and Sensitive Sensing of Copper Ions in Rat Brain. (United States)

    Huang, Pengcheng; Wu, Fangying; Mao, Lanqun


    Copper ions (Cu(2+)) in the central nervous system play a crucial role in the physiological and pathological events, so simple, selective, and sensitive detection of cerebral Cu(2+) is of great importance. In this work, we report a facile yet effective fluorescent method for sensing of Cu(2+) in rat brain using one kind of lanthanide coordination polymer nanoparticle, adenosine monophosphate (AMP) and terbium ion (Tb(3+)), i.e., AMP-Tb, as the sensing platform. Initially, a cofactor ligand, 5-sulfosalicylic acid (SSA), as the sensitizer, was introduced into the nonluminescent AMP-Tb suspension, resulting in switching on the luminescence of AMP-Tb by the removal of coordinating water molecules and concomitant energy transfer from SSA to Tb(3+). The subsequent addition of Cu(2+) into the resulting SSA/AMP-Tb can strongly quench the fluorescence because the specific coordination interaction between SSA and Cu(2+) rendered energy transfer from SSA to Tb(3+) inefficient. The decrease ratio of the fluorescence intensities of SSA/AMP-Tb at 550 nm show a linear relationship for Cu(2+) within the concentration range from 1.5 to 24 μM with a detection limit of 300 nM. The method demonstrated here is highly selective and is free from the interference of metal ions, amino acids, and the biological species commonly existing in the brain such as dopamine, lactate, and glucose. Eventually, by combining the microdialysis technique, the present method has been successfully applied in the detection of cerebral Cu(2+) in rat brain with the basal dialysate level of 1.91 ± 0.40 μM (n = 3). This method is very promising to be used for investigating the physiological and pathological events that cerebral Cu(2+) participates in.

  5. Novel polyazamacrocyclic receptor decorated core-shell superparamagnetic microspheres for selective binding and magnetic enrichment of palladium: synthesis, adsorptive behavior and coordination mechanism. (United States)

    Wu, Fengcheng; Ye, Gang; Yi, Rong; Sun, Taoxiang; Xu, Chao; Chen, Jing


    The development of economical and green technologies for the effective recovery of palladium has attracted worldwide attention in recent years. Magnetic separation involving the use of functional magnetic nanoparticles (MNPs) with superparamagnetic characteristics holds great promise in this respect. This study presents a novel class of core-shell structured superparamagnetic microspheres decorated with polyazamacrocyclic receptors, which show a highly-selective binding to Pd(ii) in HNO3 media. The superparamagnetic microspheres possess a high saturation magnetization (53.8 emu g(-1)) and high adsorption capacity (qmax≈ 105.3 μmol g(-1)), affording efficient enrichment and fast separation (within 13 seconds) of palladium under an applied magnetic field. Adsorptive behavior was fully investigated combined with the corresponding theoretical analysis by using kinetic equations and Langmuir/Freundlich isotherm models. Moreover, the coordination mechanism of the polyazamacrocyclic receptors to Pd(ii) was carefully examined based on high resolution X-ray photoelectron spectroscopy (XPS) and FT-IR spectrophotometry. A suggested mechanism involving the synergistic effect of the cyclic amines and carboxyl arms of the polyazamacrocyclic receptors was proposed to describe the coordination manner, while explaining the selectivity to Pd(ii) in HNO3 solutions. From a practical perspective, the Pd(ii)-enriched microspheres could be readily regenerated for cycle use. We conclude that this kind of polyazamacrocyclic receptor decorated superparamagnetic microsphere is of potential use for the effective recovery of Pd(ii) as well as other precious metals.

  6. Conjugated linoleic acid isomers: differences in metabolism and biological effects. (United States)

    Churruca, Itziar; Fernández-Quintela, Alfredo; Portillo, Maria Puy


    The term conjugated linoleic acid (CLA) refers to a mixture of linoleic acid positional and geometric isomers, characterized by having conjugated double bonds, not separated by a methylene group as in linoleic acid. CLA isomers appear as a minor component of the lipid fraction, found mainly in meat and dairy products from cows and sheep. The most abundant isomer is cis-9,trans-11, which represents up to 80% of total CLA in food. These isomers are metabolized in the body through different metabolic pathways, but important differences, that can have physiological consequences, are observed between the two main isomers. The trans-10,cis-12 isomer is more efficiently oxidized than the cis-9,trans-11 isomer, due to the position of its double bounds. Interest in CLA arose in its anticarcinogenic action but there is an increasing amount of specific scientific literature concerning the biological effects and properties of CLA. Numerous biological effects of CLA are due to the separate action of the most studied isomers, cis-9,trans-11 and trans-10,cis-12. It is also likely that some effects are induced and/or enhanced by these isomers acting synergistically. Although the cis-9,trans-11 isomer is mainly responsible for the anticarcinogenic effect, the trans-10,cis-12 isomer reduces body fat and it is referred as the most effective isomer affecting blood lipids. As far as insulin function is concerned, both isomers seem to be responsible for insulin resistance in humans. Finally, with regard to the immune system it is not clear whether individual isomers of CLA could act similarly or differently.

  7. A new arene-Ru based supramolecular coordination complex for efficient binding and selective sensing of green fluorescent protein. (United States)

    Mishra, Anurag; Ravikumar, Sambandam; Song, Young Ho; Prabhu, Nadarajan Saravanan; Kim, Hyunuk; Hong, Soon Ho; Cheon, Seyeon; Noh, Jaegeun; Chi, Ki-Whan


    A new dipyridyl ligand is encoded with 120° angularity between its coordination vectors by using a central pyridine carboxamide scaffold to orient two 4-(pyridin-4-ylethynyl)phenyl moieties. The N,N'-bis(4-(pyridin-4-ylethynyl)phenyl)pyridine-2,6-dicarboxamide ligand undergoes self-assembly with a diruthenium arene complex to furnish a [2 + 2] metallacycle with a wedge-like structure. The metallacycle binds to the enhanced green fluorescent protein (EGFP) variant of GFP, resulting in steady-state spectral changes in UV-Vis absorption and emission experiments. These studies indicate that the metallacycle induces conformation changes to the EGFP, disrupting the tripeptide chromophore. Furthermore, gel electrophoresis, circular dichroism and atomic force microscopy studies indicate that binding ultimately leads to aggregation of the protein. Computational investigations indicate a favorable interaction, predominantly between the metallacycle and the Arg168 residue of the EGFP. An interaction with Arg168 and related residues was previously observed for an emission-attenuating antibody, supporting that these interactions induce changes to the photophysical properties of EGFP by disrupting the tripeptidechromophore in a similar manner. Additionally, we have also described the quenching study of the reporter GFP protein in vivo by a new metal complex using reflected fluorescence microscopy. We anticipate that such metal complexes which can passively diffuse into the cells in vivo can serve as potential tools in molecular and drug targeting based biological studies.

  8. Divergent kinetic and thermodynamic hydration of a porous Cu(II) coordination polymer with exclusive CO₂ sorption selectivity. (United States)

    Du, Miao; Li, Cheng-Peng; Chen, Min; Ge, Zhi-Wei; Wang, Xi; Wang, Lei; Liu, Chun-Sen


    Selective adsorption and separation of CO2 are of great importance for different target applications. Metal-organic frameworks (MOFs) represent a promising class of porous materials for this purpose. Here we present a unique MOF material, [Cu(tba)2]n (tba = 4-(1H-1,2,4-triazol-1-yl)benzoate), which shows high CO2 adsorption selectivity over CH4/H2/O2/Ar/N2 gases (with IAST selectivity of 41-68 at 273 K and 33-51 at 293 K). By using a critical point dryer, the CO2 molecules can be well sealed in the 1D channels of [Cu(tba)2]n to allow a single-crystal X-ray analysis, which reveals the presence of not only C(δ+)-H···O(δ-) bonds between the host framework and CO2 but also quadrupole-quadrupole (CO2(δ-)···(δ+)CO2) interactions between the CO2 molecules. Furthermore, [Cu(tba)2]n will suffer divergent kinetic and thermodynamic hydration processes to form its isostructural hydrate {[Cu(tba)2](H2O)}n and a mononuclear complex [Cu(tba)2(H2O)4] via single-crystal to single-crystal transformations.

  9. Tautomeric conversion, vibrational spectra, and density functional studies on peripheral sulfur derivatives of benzothiazole and benzothiazoline isomers (United States)

    Altun, Ahmet; Kuliyev, Eziz; Aghatabay, Naz M.


    The room temperature structural (tautomerism, dimerization, conformational preference, geometry parameters) and vibrational spectral (IR and Raman) analyses have been performed on benzothiazoline (benzothiazoline-2-thione, 3-methyl-benzothiazoline-2-thione) and benzothiazole [2-mercaptobenzothiazole, 2-methylthiobenzothiazole, and bis(benzothiazole-2-ylthio)ethane] derivatives at the B3LYP/6-311++G∗∗ level of theory. Although the keto to enol transition barriers are too high over the most stable benzothiazoline isomers, vibrational spectral analyses reveal some major bands of benzothiazole isomers in the present room temperature experimental FT-IR and FT-Raman specta. Therefore, benzothiazole isomers exist at rare amounts in the powdered samples that are mainly composed of benzothiazoline isomers. The benzothiazole isomers have two stable conformations due to the orientation of their SH and SCH3 moieties. The energetic and vibrational spectral analyses suggest that the benzothiazoline-2-thione molecules can be stabilized further through the NH⋯S intermolecular hydrogen bonds in solid phase. All observed fundamental vibrational bands of the molecules have been assigned based on the calculated mode frequencies and IR/Raman intensities. The mode assignments have been expressed in terms of internal coordinates and their percent potential energy distributions. The effects of substitution at the nitrogen and peripheral sulfur atoms have been analyzed for the geometries and vibrational bands of the molecules.

  10. Polyamide-scorpion cyclam lexitropsins selectively bind AT-rich DNA independently of the nature of the coordinated metal.

    Directory of Open Access Journals (Sweden)

    Anthony T S Lo

    Full Text Available Cyclam was attached to 1-, 2- and 3-pyrrole lexitropsins for the first time through a synthetically facile copper-catalyzed "click" reaction. The corresponding copper and zinc complexes were synthesized and characterized. The ligand and its complexes bound AT-rich DNA selectively over GC-rich DNA, and the thermodynamic profile of the binding was evaluated by isothermal titration calorimetry. The metal, encapsulated in a scorpion azamacrocyclic complex, did not affect the binding, which was dominated by the organic tail.

  11. A label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) based on platinum (II)-oligonucleotide coordination induced gold nanoparticles aggregation. (United States)

    Fan, Daoqing; Zhai, Qingfeng; Zhou, Weijun; Zhu, Xiaoqing; Wang, Erkang; Dong, Shaojun


    Herein, a gold nanoparticles (AuNPs) based label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) was constructed for the first time. Four bases (G-G mismatch) mismatched streptavidin aptamer (MSAA) was used to protect AuNPs from salt-induced aggregation and recognize Pt (II) specifically. Only in the presence of Pt (II), coordination occurs between G-G bases and Pt (II), leading to the activation of streptavidin aptamer. Streptavidin coated magnetic beads (MBs) were used as separation agent to separate Pt (II)-coordinated MSAA. The residual less amount of MSAA could not efficiently protect AuNPs anymore and aggregation of AuNPs will produce a colorimetric product. With the addition of Pt (II), a pale purple-to-blue color variation could be observed by the naked eye. A detection limit of 150nM and a linear range from 0.6μM to 12.5μM for Pt (II) could be achieved without any amplification.

  12. Conformation analysis of isomers of imidoyl halides

    Energy Technology Data Exchange (ETDEWEB)

    Gershikov, A.G.; Vul' fov, A.L.; Savelova, V.A.; Drizhd, L.P.


    The possible mechanisms of the intramolecular syn-anti isomerization of imidoyl halides have been analyzed with the aid of nonempirical quantum-chemical calculations. In the liquid phase isomerization can occur after a preliminary step of ionization with the formation of nitrilium cations. The conformational features have been studied by the methods of molecular mechanics, the differences between the energies of the syn and anti isomers of a number of imidoyl halides and closely related azomethines have been calculated, and the relative equilibrium concentrations of the isomeric forms at 298/sup 0/K have been evaluated.

  13. Evolution of High Cellulolytic Activity in Symbiotic Streptomyces through Selection of Expanded Gene Content and Coordinated Gene Expression.

    Directory of Open Access Journals (Sweden)

    Adam J Book


    Full Text Available The evolution of cellulose degradation was a defining event in the history of life. Without efficient decomposition and recycling, dead plant biomass would quickly accumulate and become inaccessible to terrestrial food webs and the global carbon cycle. On land, the primary drivers of plant biomass deconstruction are fungi and bacteria in the soil or associated with herbivorous eukaryotes. While the ecological importance of plant-decomposing microbes is well established, little is known about the distribution or evolution of cellulolytic activity in any bacterial genus. Here we show that in Streptomyces, a genus of Actinobacteria abundant in soil and symbiotic niches, the ability to rapidly degrade cellulose is largely restricted to two clades of host-associated strains and is not a conserved characteristic of the Streptomyces genus or host-associated strains. Our comparative genomics identify that while plant biomass degrading genes (CAZy are widespread in Streptomyces, key enzyme families are enriched in highly cellulolytic strains. Transcriptomic analyses demonstrate that cellulolytic strains express a suite of multi-domain CAZy enzymes that are coregulated by the CebR transcriptional regulator. Using targeted gene deletions, we verify the importance of a highly expressed cellulase (GH6 family cellobiohydrolase and the CebR transcriptional repressor to the cellulolytic phenotype. Evolutionary analyses identify complex genomic modifications that drive plant biomass deconstruction in Streptomyces, including acquisition and selective retention of CAZy genes and transcriptional regulators. Our results suggest that host-associated niches have selected some symbiotic Streptomyces for increased cellulose degrading activity and that symbiotic bacteria are a rich biochemical and enzymatic resource for biotechnology.

  14. Evolution of High Cellulolytic Activity in Symbiotic Streptomyces through Selection of Expanded Gene Content and Coordinated Gene Expression. (United States)

    Book, Adam J; Lewin, Gina R; McDonald, Bradon R; Takasuka, Taichi E; Wendt-Pienkowski, Evelyn; Doering, Drew T; Suh, Steven; Raffa, Kenneth F; Fox, Brian G; Currie, Cameron R


    The evolution of cellulose degradation was a defining event in the history of life. Without efficient decomposition and recycling, dead plant biomass would quickly accumulate and become inaccessible to terrestrial food webs and the global carbon cycle. On land, the primary drivers of plant biomass deconstruction are fungi and bacteria in the soil or associated with herbivorous eukaryotes. While the ecological importance of plant-decomposing microbes is well established, little is known about the distribution or evolution of cellulolytic activity in any bacterial genus. Here we show that in Streptomyces, a genus of Actinobacteria abundant in soil and symbiotic niches, the ability to rapidly degrade cellulose is largely restricted to two clades of host-associated strains and is not a conserved characteristic of the Streptomyces genus or host-associated strains. Our comparative genomics identify that while plant biomass degrading genes (CAZy) are widespread in Streptomyces, key enzyme families are enriched in highly cellulolytic strains. Transcriptomic analyses demonstrate that cellulolytic strains express a suite of multi-domain CAZy enzymes that are coregulated by the CebR transcriptional regulator. Using targeted gene deletions, we verify the importance of a highly expressed cellulase (GH6 family cellobiohydrolase) and the CebR transcriptional repressor to the cellulolytic phenotype. Evolutionary analyses identify complex genomic modifications that drive plant biomass deconstruction in Streptomyces, including acquisition and selective retention of CAZy genes and transcriptional regulators. Our results suggest that host-associated niches have selected some symbiotic Streptomyces for increased cellulose degrading activity and that symbiotic bacteria are a rich biochemical and enzymatic resource for biotechnology.

  15. Competitive coordination of Cu2+ between cysteine and pyrophosphate ion: toward sensitive and selective sensing of pyrophosphate ion in synovial fluid of arthritis patients. (United States)

    Deng, Jingjing; Yu, Ping; Yang, Lifen; Mao, Lanqun


    Direct selective and sensitive sensing of pyrophosphate ion (PPi) in synovial fluid of arthritis patients is of great importance because of its crucial roles in the diagnosis and therapy of arthritic diseases. In this study, we demonstrate a sensitive and selective method for PPi sensing in synovial fluid of arthritis patients with gold nanoparticles (Au-NPs) as the signal readout based on the competitive coordination chemistry of Cu(2+) between cysteine and PPi. Initially, Au-NPs stabilized with cysteine are red in color and exhibit absorption at 519 nm in the UV-vis spectrum. The addition of an aqueous solution of Cu(2+) to the Au-NPs dispersion containing cysteine causes the aggregation of Au-NPs, resulting in the wine red-to-blue color change and the appearance of a new absorption at 650 nm in the UV-vis spectrum of the Au-NPs dispersion. The subsequent addition of PPi to the Au-NPs aggregation well solubilizes the aggregated Au-NPs with the changes in both the color and the UV-vis spectrum of the Au-NPs dispersion. These changes are ascribed to the higher coordination reactivity between Cu(2+) and PPi than that between Cu(2+) and cysteine. On the basis of this, the concentration of PPi can be visualized with the naked eyes through the blue-to-wine red color change of the Au-NPs dispersion and quantitatively determined by UV-vis spectroscopy. Under the optimized conditions, the ratio of the absorbance at 650 nm (A(650)) to that at 519 nm (A(519)) shows a linear relationship with PPi concentration within a concentration range from 130 nM to 1.3 mM. The method demonstrated here is highly sensitive, free from the interference from other species in the synovial fluid, and is thus particularly useful for fast and simple clinic diagnosis of arthritic diseases.

  16. The interstellar chemistry of H2C3O isomers (United States)

    Loison, Jean-Christophe; Agúndez, Marcelino; Marcelino, Núria; Wakelam, Valentine; Hickson, Kevin M.; Cernicharo, José; Gerin, Maryvonne; Roueff, Evelyne; Guélin, Michel


    We present the detection of two H2C3O isomers, propynal and cyclopropenone, toward various starless cores and molecular clouds, together with upper limits for the third isomer propadienone. We review the processes controlling the abundances of H2C3O isomers in interstellar media showing that the reactions involved are gas-phase ones. We show that the abundances of these species are controlled by kinetic rather than thermodynamic effects. PMID:27013768

  17. Nuclear isomers as ultra-high-energy-density materials (United States)

    Poppe, C. H.; Weiss, M. S.; Anderson, J. D.


    A major energy advance could result if the enormous potential of nuclear energy storage could be tapped without the penalty of radioactive by-products. Recent research has uncovered a new method for nuclear energy storage with high energy density and no residual radioactivity. Nuclear isomers are metastable states of atomic nuclei which release their energy in a prompt burst of electromagnetic radiation; in many cases the product remaining after decay of isomer is stable and no activity is produced by the electromagnetic decay. Two kinds of nuclear isomers are known: spin isomers and shape isomers. The former lacks a release mechanism. Theory has predicted the existence of shape isomers in the mass range around mercury and gold where decay by fission is prohibited. Experiments on the existence of fissionless shape isomers have resulted in evidence for 27 different shape isomers in isotopes of mercury, lead, and thallium. Three potential candidates for release mechanisms have been identified to date: neutron catalysis (Hf- 178), laser-electron-nuclear coupling (Th-229), and Stark-shift-induced mixing (speculative). Ways of producing nonfissioning shape isomers are discussed.

  18. Anion Receptor Design: Exploiting Outer-Sphere Coordination Chemistry To Obtain High Selectivity for Chloridometalates over Chloride. (United States)

    Carson, Innis; MacRuary, Kirstian J; Doidge, Euan D; Ellis, Ross J; Grant, Richard A; Gordon, Ross J; Love, Jason B; Morrison, Carole A; Nichol, Gary S; Tasker, Peter A; Wilson, A Matthew


    High anion selectivity for PtCl6(2-) over Cl(-) is shown by a series of amidoamines, R(1)R(2)NCOCH2CH2NR(3)R(4) (L1 with R(1) = R(4) = benzyl and R(2) = R(3) = phenyl and L3 with R(1) = H, R(2) = 2-ethylhexyl, R(3) = phenyl and R(4) = methyl), and amidoethers, R(1)R(2)NCOCH2CH2OR(3) (L5 with R(1) = H, R(2) = 2-ethylhexyl and R(3) = phenyl), which provide receptor sites which extract PtCl6(2-) preferentially over Cl(-) in extractions from 6 M HCl solutions. The amidoether receptor L5 was found to be a much weaker extractant for PtCl6(2-) than its amidoamine analogues. Density functional theory calculations indicate that this is due to the difficulty in protonating the amidoether to generate a cationic receptor, LH(+), rather than the latter showing weaker binding to PtCl6(2-). The most stable forms of the receptors, LH(+), contain a tautomer in which the added proton forms an intramolecular hydrogen bond to the amide oxygen atom to give a six-membered proton chelate. Dispersion-corrected DFT calculations appear to suggest a switch in ligand conformation for the amidoamine ligands to an open tautomer state in the complex, such that the cationic N-H or O-H groups are also readily available to form hydrogen bonds to the PtCl6(2-) ion, in addition to the array of polarized C-H bonds. The predicted difference in energies between the proton chelate and nonchelated tautomer states for L1 is small, however, and the former is found in the X-ray crystal structure of the assembly [(L1H)2PtCl6]. The DFT calculations and the X-ray structure indicate that all LH(+) receptors present an array of polarized C-H groups to the large, charge diffuse PtCl6(2-) anion resulting in high selectivity of extraction of PtCl6(2-) over the large excess of chloride.

  19. Structures and Stability of HNS2 Isomers

    Institute of Scientific and Technical Information of China (English)

    CHI,Yu-Juan(池玉娟); YU,Hai-Tao(于海涛); Fu,Hong-Gang(傅宏刚); HUANG,Xu-Ri(黄旭日); LI,Ze-Sheng(李泽生); SUN,Jia-Zhong(孙家钟)


    Potential energy surface of HNS2 is investigated by means of second-order Moller-Plesset perturbation theory (MP2) and QCISD(T) (single-point) methods. At final QCISD (T)/6-311++ G(3df,2p)//MP2/6-311++ G(d,p) level with zero-point vibrational energies included, cis-HNSS is found to be global minimum on the potential energy surface, followed by low-lying trans-HNSS, HN(S)S(C2v), cis-HSNS, cis-HSSN,rans-HSNS, trans-HSSN, and HN(S)S(Cs) by 13.46,66.92, 78.25, 80.38, 81.22, 81.38 and 86.40 kJ/mol, respectively. A new high-lying HS(N)S isomer with Cs symmetry is located on the potential energy surface. The kinetic stabilities of all isomers are predicted. Comparisons are made for HNS2 with its analogues, HNO2, HPS2 and HPO2. The causes that lead to the differences between HNS2 and its analogues are hypervalent capacity of phosphorus and distinct electronegativities of hydrogen, nitrogen and phosphorus.

  20. Structures and Stability of NHS2 Isomers

    Institute of Scientific and Technical Information of China (English)

    池玉娟; 于海涛; 等


    Potential energy surface of HNS2 is investigated by means of second-order Moller-Plesset Perturbation theory(MP2) and QCISD(T) (single-point)methods,At final QCISD (T)/6-311++G(3df,2p)//MP2/6-311+G(d,p),level with zero-point vibrational energies included,cis-NHSS is found to be global minimum on the potential energy sufrace,followed by low-lying trans-HNSS ,HN(S)S(C2v).cis-HSNS,cis-NSSN,trans-HSNS,trans-NSSN,and HN(S)S(Cs) by 13.46,66.92,78.25,80.38,81.22,81.38 and 86.40 kJ/mol,respectively.A new high-lying HS(N)S isomer with Cs symmetry is located on the potential energy surface ,The kinetic stabilities of all isomers are predicted.Comprisons are made for HNS2 with its analogues,NHO2,HPS2 and HPO2,The causes that lead to the differences between HNS2 and its analogues are hypervalent capacity of phosphorus and distinct electronegativities of hydrogen,nitrogen and phosphorus.

  1. HLA-DRB1 may be antagonistically regulated by the coordinately evolved promoter and 3'-UTR under stabilizing selection.

    Directory of Open Access Journals (Sweden)

    Benrong Liu

    Full Text Available HLA-DRB1 is the most polymorphic MHC (major histocompatibility complex class II gene in human, and plays a crucial role in the development and function of the immune system. Extensive polymorphisms exist in the promoter and 3'-UTR of HLA-DRB1, especially a LTR (Long terminal repeat element in the promoter, which may be involved in the expression regulation. However, it remains unknown how the polymorphisms in the whole promoter region and 3'-UTR to regulate the gene expression. In this study, we investigated the extensive polymorphisms in the HLA-DRB1 promoter and 3'-UTR, and how these polymorphisms affect the gene expression in both independent and jointly manners. It was observed that most of the haplotypes in the DRB1 promoter and 3'-UTR were clustered into 4 conserved lineages (H1, H2, H3 and H4, and showed high linkage disequilibrium. Compared with H1 and H2 lineage, a LTR element in the promoter of H3 and H4 lineage significantly suppressed the promoter activity, whereas the activity of the linked 3'-UTR increased, leading to no apparent difference in the final expression product between H1/H2 and H3/H4 lineage. Nevertheless, compared with the plasmid with a promoter and 3'-UTR from the same lineage, the recombinant plasmid with a promoter from H2 and a 3'-UTR from H3 showed about double fold increased luciferase activity, Conversely, the recombinant plasmid with a promoter from H3 and a 3'-UTR from H2 resulted in about 2-fold decreased luciferase activity. These results indicate that the promoter and 3'-UTR of HLA-DRB1 may antagonistically regulate the gene expression, which may be subjected to stabilizing selection. These findings may provide a novel insight into the mechanisms of the diseases associated with HLA-DRB1 genes.

  2. Lipid and Glycolipid Isomer Analyses Using Ultra-High Resolution Ion Mobility Spectrometry Separations

    Directory of Open Access Journals (Sweden)

    Roza Wojcik


    Full Text Available Understanding the biological roles and mechanisms of lipids and glycolipids is challenging due to the vast number of possible isomers that may exist. Mass spectrometry (MS measurements are currently the dominant approach for studying and providing detailed information on lipid and glycolipid presence and changes. However, difficulties in distinguishing the many structural isomers, due to the distinct lipid acyl chain positions, double bond locations or specific glycan types, inhibit the delineation and assignment of their biological roles. Here we utilized ultra-high resolution ion mobility spectrometry (IMS separations by applying traveling waves in a serpentine multi-pass Structures for Lossless Ion Manipulations (SLIM platform to enhance the separation of selected lipid and glycolipid isomers. The multi-pass arrangement allowed the investigation of paths ranging from ~16 m (one pass to ~60 m (four passes for the distinction of lipids and glycolipids with extremely small structural differences. These ultra-high resolution SLIM IMS-MS analyses provide a foundation for exploring and better understanding isomer-specific biological activities and disease processes.

  3. Infrared spectroscopy of the acetyl cation and its protonated ketene isomer

    Energy Technology Data Exchange (ETDEWEB)

    Mosley, J. D.; Young, J. W.; Duncan, M. A. [Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States)


    [C{sub 2},H{sub 3},O]{sup +} ions are generated with a pulsed discharge in a supersonic expansion containing methyl acetate or acetone. These ions are mass selected and their infrared spectra are recorded via laser photodissociation and the method of argon tagging. Computational chemistry is employed to investigate structural isomers and their spectra. The acetyl cation (CH{sub 3}CO{sup +}) is the global minimum and protonated ketene (CH{sub 2}COH{sup +}) is the next lowest energy isomer (+176.2 kJ/mol). When methyl acetate is employed as the precursor, the infrared spectrum reveals that only the acetyl cation is formed. Partially resolved rotational structure reveals rotation about the C{sub 3} axis. When acetone is used as the precursor, acetyl is still the most abundant cation, but there is also a minor component of protonated ketene. Computations reveal a significant barrier to interconversion between the two isomers (+221 kJ/mol), indicating that protonated ketene must be obtained via kinetic trapping. Both isomers may be present in interstellar environments, and their implications for astrochemistry are discussed.

  4. Table of superdeformed nuclear bands and fission isomers

    Energy Technology Data Exchange (ETDEWEB)

    Firestone, R.B. [Lawrence Berkeley Lab., CA (United States); Singh, B. [McMaster Univ., Hamilton, ON (Canada)


    A minimum in the second potential well of deformed nuclei was predicted and the associated shell gaps are illustrated in the harmonic oscillator potential shell energy surface calculations shown in this report. A strong superdeformed minimum in {sup 152}Dy was predicted for {beta}{sub 2}-0.65. Subsequently, a discrete set of {gamma}-ray transitions in {sup 152}DY was observed and, assigned to the predicted superdeformed band. Extensive research at several laboratories has since focused on searching for other mass regions of large deformation. A new generation of {gamma}-ray detector arrays is already producing a wealth of information about the mechanisms for feeding and deexciting superdeformed bands. These bands have been found in three distinct regions near A=l30, 150, and 190. This research extends upon previous work in the actinide region near A=240 where fission isomers were identified and also associated with the second potential well. Quadrupole moment measurements for selected cases in each mass region are consistent with assigning the bands to excitations in the second local minimum. As part of our committment to maintain nuclear structure data as current as possible in the Evaluated Nuclear Structure Reference File (ENSDF) and the Table of Isotopes, we have updated the information on superdeformed nuclear bands. As of April 1994, we have complied data from 86 superdeformed bands and 46 fission isomers identified in 73 nuclides for this report. For each nuclide there is a complete level table listing both normal and superdeformed band assignments; level energy, spin, parity, half-life, magneto moments, decay branchings; and the energies, final levels, relative intensities, multipolarities, and mixing ratios for transitions deexciting each level. Mass excess, decay energies, and proton and neutron separation energies are also provided from the evaluation of Audi and Wapstra.

  5. Stereospecific Synthesis of the Geometrical Isomers of a Natural Product (United States)

    Grove, T.; DiLella, D.; Volker, E.


    Stereospecific synthesis of a geometrical isomer is not a common topic for the introductory organic chemistry laboratory. We have developed and tested an experiment for the synthesis of (Z) and (E) isomers that has been performed successfully by undergraduate students. The experiment is presented to the students as a puzzle in which they must…

  6. The Structures and Stability of HNOS Isomers

    Institute of Scientific and Technical Information of China (English)

    CHI,Yu-Juan; YU,Hai-Tao; FU,Hong-Gang; XIN,Bai-Fu; LI,Ze-Sheng; SUN,Jia-Zhong


    Potential energy surface of HNOS system is investigated by means ofMP2 method with 6-311 ++ G(d, p)basis set. The energyfor each minimum and saddle point on the potential energy surface is corrected at the QCISD(T)/6-311 ++ G(3df, 2p) level of theory with zero-point vibrational energy included. As a result, eighteen isoners are theoretically predicted and cis-HNSO is found to be global minimum on the potential energy surface. Wherein, fourteen isoners are considered as kinetically stable species, and should be experimentally observed. Comparisons are made for HNOS system with its analogues, HNO2 and HNS2. The nature of bonding and isomers' stability of HNOS system are similar to HNS2. The obvious similarities and discrepancies among HNOS, HNO2 and HNS2are attributed to the hypervalent capacity of sulfur, oxygen and nitrogen atoms.

  7. Analysis of Heme oxygenase isomers in rat

    Institute of Scientific and Technical Information of China (English)

    Zhen-Wei Xia; Wen-Jun Cui; Xue-Hong Zhang; Qing-Xiang Shen; Jian Wang; Yun-Zhu Li; Shen-Nian Chen; Shan-Chang Yu


    AIM: To purify and identify heme oxygenase (HO) isomers which exist in rat liver, spleen and brain treated with hematin and phenylhydrazine and in untreated rat liver and to investigate the characteristics of HO isomers, to isolate and confirm the rat HO-1 cDNA that actually encodes HO-1 by expressing cDNA in monkey kidney cells (COS-1 cells), to prepare the rat heme oxygenase-1 (HO-1) mutant and to detect inhibition of HO-1 mutated enzyme.METHODS: First, rat liver, spleen and brain microsomal fi-actions were purified by DEAE-Sephacel and hydroxylapatite. The characteristics including activity, immunity and inducibility of two isomers (HO-1 and HO-2), and their apparent molecular weight were measured by detecting enzymatic activities, SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting analysis, respectively. Second, plasmid pcDNA3HO1 containing native rat HO-1 cDNA and pcDNA3HO1D25 carrying mutated rat HO-1 cDNA (His25Ala) were constructed by site-directed mutagenesis. COS-1 cells transfected with pcDNA3HO1 and pcDNA3HO1D25 were collected and disrupted by sonication, the microsomes were prepared by ultracentrifugation. Third, the inhibition of rat HO-1 mutant was analyzed.RESULTS: Two isomers were purified and identified in treated rat liver, spleen, brain and untreated rat liver. HO-1 was the predominant form with a ratio of 2.0:1 and 3.2:1 of HO-1 and HO-2 in liver and spleen, respectively, but only the activity of HO-2 in the brain and untreated liver could be detected. The apparent molecular weights of HO-1 and HO-2 were about Mr 30 000 and Mr 36 000 under reducing conditions, respectively. The antiserum against liver HO-2 was employed in Western blotting analysis, the reactivity of HO-1 in the liver was not observed. The plasmid pcDNA3HO1 was highly expressed in endoplasmic reticulum of transfected COS-1 cells. The specific activity was ≈5-fold higher than that of the control. However, the enzyme activity of mutated HO-1 declined. While

  8. Regiospecific formation of cobamide isomers is directed by CobT. (United States)

    Crofts, Terence S; Hazra, Amrita B; Tran, Jennifer L A; Sokolovskaya, Olga M; Osadchiy, Vadim; Ad, Omer; Pelton, Jeffrey; Bauer, Stefan; Taga, Michiko E


    Cobamides, which include vitamin B₁₂ (cobalamin), are a class of modified tetrapyrroles synthesized exclusively by prokaryotes that function as cofactors for diverse biological processes. Cobamides contain a centrally bound cobalt ion that coordinates to upper and lower axial ligands. The lower ligand is covalently linked to a phosphoribosyl moiety through an alpha-glycosidic bond formed by the CobT enzyme. CobT can catalyze the phosphoribosylation of a variety of substrates. We investigated the ability of CobT to act on either of two nitrogen atoms within a single, asymmetric benzimidazole substrate to form two isomeric riboside phosphate products. Reactions containing asymmetric benzimidazoles as substrates for homologues of CobT from different bacteria resulted in the production of distinct ratios of two isomeric products, with some CobT homologues favoring the production of a single isomer and others forming a mixture of products. These preferences were reflected in the production of cobamide isomers with lower ligands attached in different orientations, some of which are novel cobamides that have not been characterized previously. Two isomers of methoxybenzimidazolylcobamide were found to be unequal in their ability to support ethanolamine ammonia-lyase dependent growth in Salmonella enterica, suggesting that CobT's regiospecificity could be biologically important. We also observed differences in pKa, which can influence the reactivity of the cofactor and could contribute to these distinct biological activities. Relaxed regiospecificity was achieved by introducing a single point mutation in an active site residue of CobT. These new cobamide isomers could be used to probe the mechanisms of cobamide-dependent enzymes.

  9. Backbone cyclization of analgesic conotoxin GeXIVA facilitates direct folding of the ribbon isomer. (United States)

    Wu, Xiaosa; Huang, Yen-Hua; Kaas, Quentin; Harvey, Peta J; Wang, Conan K; Tae, Han-Shen; Adams, David J; Craik, David J


    Conotoxin GeXIVA inhibits the α9α10 nicotinic acetylcholine receptor (nAChR) and is analgesic in animal models of pain. α-conotoxins have four cysteines, which can have three possible disulfide connectivities: globular (CysI-CysIII and CysII-CysIV); ribbon (CysI-CysIV and CysII-CysIII) or bead (CysI-CysII and CysIII-CysIV). Native α-conotoxins preferably adopt the globular connectivity, and previous studies of α-conotoxins have focused on the globular isomers as the ribbon and bead isomers typically have lower potency at nAChRs than the globular form. A recent report showed that the bead and ribbon isomers of GeXIVA are more potent than the globular isomer, with low nanomolar half maximal inhibitory concentrations (IC50s). Despite this high potency, the therapeutic potential of GeXIVA is limited because, like most peptides, it is susceptible to proteolytic degradation and is challenging to synthesize in high yield. Here we used backbone cyclization as a strategy to improve the folding yield as well as increase the serum stability of ribbon GeXIVA while preserving activity at the α9α10 nAChR. Specifically, cyclization of ribbon GeXIVA with a two-residue linker maintained the biological activity at the human α9α10 nAChR and improved stability in human serum. Short linkers led to selective formation of the ribbon disulfide isomer without requiring orthogonal protection. Overall, this study highlights the value of backbone cyclization in directing folding, improving yields and stabilizing conotoxins with therapeutic potential. Copyright © 2017, The American Society for Biochemistry and Molecular Biology.

  10. Poisson Coordinates. (United States)

    Li, Xian-Ying; Hu, Shi-Min


    Harmonic functions are the critical points of a Dirichlet energy functional, the linear projections of conformal maps. They play an important role in computer graphics, particularly for gradient-domain image processing and shape-preserving geometric computation. We propose Poisson coordinates, a novel transfinite interpolation scheme based on the Poisson integral formula, as a rapid way to estimate a harmonic function on a certain domain with desired boundary values. Poisson coordinates are an extension of the Mean Value coordinates (MVCs) which inherit their linear precision, smoothness, and kernel positivity. We give explicit formulas for Poisson coordinates in both continuous and 2D discrete forms. Superior to MVCs, Poisson coordinates are proved to be pseudoharmonic (i.e., they reproduce harmonic functions on n-dimensional balls). Our experimental results show that Poisson coordinates have lower Dirichlet energies than MVCs on a number of typical 2D domains (particularly convex domains). As well as presenting a formula, our approach provides useful insights for further studies on coordinates-based interpolation and fast estimation of harmonic functions.

  11. High-K isomers in {sup 176}W and mechanisms of K-violation

    Energy Technology Data Exchange (ETDEWEB)

    Crowell, B.; Janssens, R.V.F.; Blumenthal, D.J. [and others


    K-isomers are states in deformed nuclei whose {gamma}-decay is hindered by selection rules involving K, the projection of the angular momentum along the axis of symmetry of the nucleus. Previous work with the Argonne Notre Dame BGO Array delineated the existence of two K-isomers in {sup 176}W, one of which had a very unusual pattern of decay. A short description of this work was published as a letter, and a more complete account is being readied for submission. These results provided evidence that quantum-mechanical fluctuations in the nuclear shape may be responsible for some of the observed K-violating transitions. In addition, hints were present in the data of the existence of another K-isomer with an even higher in. An experiment was performed in September 1994 to observe this isomer, using the reaction {sup 50}Ti({sup 130}Te,4n), and a technique in which recoiling {sup 176}W nuclei were created 17-cm upstream of the center of the array and caught on a Pb catcher foil at the center. Intense ({approximately} 3 pnA) beams of {sup 130}Te were supplied by the ECR source using a new sputtering technique. The recoil-shadow geometry was highly successful at removing the background from non-isomeric decays, allowing the weakly populated K-isomers to be detected cleanly. In addition, the availability of pulsed beams from ATLAS and the timing data from the BGO array provided a second technique for isolating the decays of interest, by selecting events in which a given number of BGO detectors fired between beam pulses. This method was used in the previous experiment, and was also applied in this experiment as a second level of selection. As a result, gamma-ray transitions were detected in the present experiment with intensities as small as {approximately} 0.02 % of the {sup 176}W reaction channel. The existence of the new isomer was confirmed, and a partial level-scheme was constructed.

  12. Quantitative trace analysis of eight chloramphenicol isomers in urine by chiral liquid chromatography coupled to tandem mass spectrometry. (United States)

    Berendsen, Bjorn J A; Essers, Martien L; Stolker, Linda A A M; Nielen, Michel W F


    Chloramphenicol is a broad-spectrum antibiotic with, apart from its human medicinal use, veterinary abuse in all major food-producing animals. Chloramphenicol occurs in four stereoisomers (all para-nitro substituted) and furthermore four meta-nitro analogs of chloramphenicol exist. In this paper these are referred to as eight chloramphenicol isomers. According to EU regulations an analytical method should be able to discriminate the analyte from interfering substances that might be present in the sample, including isomers. For the first time a quantitative method for the analysis of trace levels of eight chloramphenicol isomers in urine by chiral liquid chromatography in combination with tandem mass spectrometric detection is reported. The separation of the isomers on the analytical column, the clean-up of urine and the selectivity of the monitored product ions turned out to be critical parameters. To obtain reproducible retention isocratic elution on a chiral AGP column was applied. For urine samples matrix compounds present in the final extract caused decreased retention of the isomers on the chiral stationary phase and a lack of chromatographic resolution. Therefore an extended clean-up procedure that combines solid phase extraction and liquid-liquid extraction had to be developed. The final method was fully validated and showed satisfactory performance for all isomers with decision limits (CCα) ranging from 0.005 to 0.03 μg L(-1) and within-laboratory reproducibility of all isomers below 20% at the minimum required performance limit level of 0.3 μg L(-1).

  13. A PCP Pincer Ligand for Coordination Polymers with Versatile Chemical Reactivity: Selective Activation of CO2 Gas over CO Gas in the Solid State. (United States)

    He, Junpeng; Waggoner, Nolan W; Dunning, Samuel G; Steiner, Alexander; Lynch, Vincent M; Humphrey, Simon M


    A tetra(carboxylated) PCP pincer ligand has been synthesized as a building block for porous coordination polymers (PCPs). The air- and moisture-stable PCP metalloligands are rigid tetratopic linkers that are geometrically akin to ligands used in the synthesis of robust metal-organic frameworks (MOFs). Here, the design principle is demonstrated by cyclometalation with Pd(II) Cl and subsequent use of the metalloligand to prepare a crystalline 3D MOF by direct reaction with Co(II) ions and structural resolution by single crystal X-ray diffraction. The Pd-Cl groups inside the pores are accessible to post-synthetic modifications that facilitate chemical reactions previously unobserved in MOFs: a Pd-CH3 activated material undergoes rapid insertion of CO2 gas to give Pd-OC(O)CH3 at 1 atm and 298 K. However, since the material is highly selective for the adsorption of CO2 over CO, a Pd-N3 modified version resists CO insertion under the same conditions.

  14. Mechanochemical and Conventional Synthesis of Zn(II)/Cd(II) Luminescent Coordination Polymers: Dual Sensing Probe for Selective Detection of Chromate Anions and TNP in Aqueous Phase. (United States)

    Parmar, Bhavesh; Rachuri, Yadagiri; Bisht, Kamal Kumar; Laiya, Ridhdhi; Suresh, Eringathodi


    Isostructural Zn(II)/Cd(II) mixed ligand coordination polymers (CPs) {[M(IPA)(L)]}n (CP1 and CP2) built from isophthalic acid (H2IPA) and 3-pyridylcarboxaldehyde nicotinoylhydrazone (L) were prepared using versatile synthetic routes: viz., diffusion of precursor solutions, conventional reflux methods, and green mechanochemical (grinding) reactions. Both robust CPs synthesized by different routes were characterized by various analytical methods, and their thermal and chemical stability as well as the phase purity was established. Crystallographic studies revealed that CP1 and CP2 are isostructural frameworks and feature a double-lined two-dimensional network composed of Zn(2+)/Cd(2+) nodes connected through IPA and pillared by the Schiff base ligand L with a double-walled edge. The photoluminescent (PL) properties of CP1 and CP2 have been exploited as dual detection fluorosensors for hexavalent chromate anions (CrO4(2-)/Cr2O7(2-)) and 2,4,6-trinitrophenol (TNP) because it was observed that the emission intensity of aqueous suspensions of CPs selectively quenches by chromate anions or TNP among large pools of different anions or nitro compounds, respectively. Competitive experiments in the presence of interfering anions/other nitro compounds also revealed no major effect in the quenching efficiency, suggesting the selective detection of hexavalent chromate anions as well as TNP by the LCPs. The limits of detection by CP1 for CrO4(2-)/Cr2O7(2-) and TNP are 4 ppm/4 ppm and 28 ppb, respectively, whereas the limits of detection by CP2 for the same analytes are 1 ppm/1 ppm and 14 ppb, respectively. A probable mechanism for the quenching phenomena is also discussed.

  15. Configuration Control in the Synthesis of Homo- and Heteroleptic Bis(oxazolinylphenolato/thiazolinylphenolato) Chelate Ligand Complexes of Oxorhenium(V): Isomer Effect on Ancillary Ligand Exchange Dynamics and Implications for Perchlorate Reduction Catalysis. (United States)

    Liu, Jinyong; Wu, Dimao; Su, Xiaoge; Han, Mengwei; Kimura, Susana Y; Gray, Danielle L; Shapley, John R; Abu-Omar, Mahdi M; Werth, Charles J; Strathmann, Timothy J


    This study develops synthetic strategies for N,N-trans and N,N-cis Re(O)(LO-N)2Cl complexes and investigates the effects of the coordination spheres and ligand structures on ancillary ligand exchange dynamics and catalytic perchlorate reduction activities of the corresponding [Re(O)(LO-N)2](+) cations. The 2-(2'-hydroxyphenyl)-2-oxazoline (Hhoz) and 2-(2'-hydroxyphenyl)-2-thiazoline (Hhtz) ligands are used to prepare homoleptic N,N-trans and N,N-cis isomers of both Re(O)(hoz)2Cl and Re(O)(htz)2Cl and one heteroleptic N,N-trans Re(O)(hoz)(htz)Cl. Selection of hoz/htz ligands determines the preferred isomeric coordination sphere, and the use of substituted pyridine bases with varying degrees of steric hindrance during complex synthesis controls the rate of isomer interconversion. The five corresponding [Re(O)(LO-N)2](+) cations exhibit a wide range of solvent exchange rates (1.4 to 24,000 s(-1) at 25 °C) and different LO-N movement patterns, as influenced by the coordination sphere of Re (trans/cis), the noncoordinating heteroatom on LO-N ligands (O/S), and the combination of the two LO-N ligands (homoleptic/heteroleptic). Ligand exchange dynamics also correlate with the activity of catalytic reduction of aqueous ClO4(-) by H2 when the Re(O)(LO-N)2Cl complexes are immobilized onto Pd/C. Findings from this study provide novel synthetic strategies and mechanistic insights for innovations in catalytic, environmental, and biomedical research.

  16. Separation of p-divinylbenzene by selective room-temperature adsorption inside Mg-CUK-1 prepared by aqueous microwave synthesis. (United States)

    Saccoccia, Beau; Bohnsack, Alisha M; Waggoner, Nolan W; Cho, Kyung Ho; Lee, Ji Sun; Hong, Do-Young; Lynch, Vincent M; Chang, Jong-San; Humphrey, Simon M


    A new Mg(II) -based version of the porous coordination polymer CUK-1 with one-dimensional pore structure was prepared by microwave synthesis in water. Mg-CUK-1 is moisture-stable, thermally stable up to 500 °C, and shows unusual reversible soft-crystal behavior: dehydrated single crystals of the material selectively adsorb a range of organic molecules at ambient temperature and pressure. Both polar and apolar aromatic compounds, including pyridine, benzene, p-xylene, and p-divinylbenzene (p-DVB), are all readily adsorbed, while other isomers from complex mixtures of xylenes or DVBs are selectively excluded. The solvent-loaded structures have been studied by single-crystal X-ray diffraction. Time-dependent liquid sorption experiments using commercially available DVB demonstrate a high and rapid selective adsorption of p-DVB and exclusion of m-DVB and ethylvinylbenzene isomers.

  17. Comparison of the repeated dose toxicity of isomers of dinitrotoluene. (United States)

    Lent, Emily May; Crouse, Lee C B; Quinn, Michael J; Wallace, Shannon M


    Dinitrotoluene (DNT) is a nitroaromatic explosive used in propellant mixtures and in the production of plastics. Isomers of DNT were administered daily via oral gavage to male Sprague-Dawley rats for 14 days to determine the subacute toxicity of individual isomers of DNT. The 3,5-DNT isomer was the most toxic isomer, inducing weight loss and mortality within 3 days. Cyanosis and anemia were observed for all isomers. Exposure to 2,4-, 2,6-, and 3,5-DNT resulted in decreased testes mass and degenerative histopathological changes. Increased splenic mass was observed for 2,4-, 2,6-, and 2,5-DNT. Extramedullary hematopoiesis of the spleen was noted for all isomers, while lymphoid hyperplasia of the spleen was noted for all isomers except 2,5-DNT. Increased liver mass was observed for 2,3-DNT and 3,4-DNT. Hepatocellular lesions were observed for 2,6-DNT and 2,4-DNT. Neurotoxic effects were noted for 3,4-DNT, 2,4-DNT, and 3,5-DNT.

  18. Effect of C6-olefin isomers on π-complexation for purification of 1-hexene by reactive extractive distillation

    NARCIS (Netherlands)

    Wentink, A.E.; Kockmann, D.; Kuipers, N.J.M.; Haan, de A.B.; Scholz, J.; Mulder, H.


    Separation of α-olefins from other olefin isomers is a difficult and expensive operation because of the low selectivities encountered. A promising alternative is π-complexation in combination with extractive distillation: reactive extractive distillation (RED). In this paper, silver nitrate dissolve

  19. Adsorption and Diffusion of Xylene Isomers on Mesoporous Beta Zeolite

    Directory of Open Access Journals (Sweden)

    Aixia Song


    Full Text Available A systematic and detailed analysis of adsorption and diffusion properties of xylene isomers over Beta zeolites with different mesoporosity was conducted. Adsorption isotherms of xylene isomers over microporous and mesoporous Beta zeolites through gravimetric methods were applied to investigate the impact of mesopores inside Beta zeolites on the adsorption properties of xylene isomers in the pressure range of lower 20 mbar. It is seen that the adsorption isotherms of three xylene isomers over microporous and mesoporous Beta zeolites could be successfully described by the single-site Toth model and the dual-site Toth model, respectively. The enhanced adsorption capacities and decreased Henry’s constants (KH and the initial heats of adsorption (Qst for the all xylene isomers are observed after the introduction of mesopores in the zeolites. For three xylene isomers, the order of Henry’s constant is o-xylene > m-xylene > p-xylene, whereas the adsorption capacities of Beta zeolite samples for xylene isomers execute the following order of o-xylene > p-xylene > m-xylene, due to the comprehensive effects from the molecular configuration and electrostatic interaction. At the same time, the diffusion properties of xylene isomers in the mesoporous Beta zeolites were also studied through the desorption curves measured by the zero length column (ZLC method at 333–373 K. It turned out that the effective diffusion time constant (Deff/R2 is a growing trend with the increasing mesoporosity, whereas the tendency of the activation energy is just the reverse, indicating the contribution of mesopores to facilitate molecule diffusion by shortening diffusion paths and reducing diffusion resistances. Moreover, the diffusivities of three xylene isomers in all Beta zeolites follow an order of p-xylene > m-xylene > o-xylene as opposed to KH, conforming the significant effects of adsorbate-adsorbent interaction on the diffusion.

  20. Separation of Opiate Isomers Using Electrospray Ionization and Paper Spray Coupled to High-Field Asymmetric Waveform Ion Mobility Spectrometry (United States)

    Manicke, Nicholas E.; Belford, Michael


    One limitation in the growing field of ambient or direct analysis methods is reduced selectivity caused by the elimination of chromatographic separations prior to mass spectrometric analysis. We explored the use of high-field asymmetric waveform ion mobility spectrometry (FAIMS), an ambient pressure ion mobility technique, to separate the closely related opiate isomers of morphine, hydromorphone, and norcodeine. These isomers cannot be distinguished by tandem mass spectrometry. Separation prior to MS analysis is, therefore, required to distinguish these compounds, which are important in clinical chemistry and toxicology. FAIMS was coupled to a triple quadrupole mass spectrometer, and ionization was performed using either a pneumatically assisted heated electrospray ionization source (H-ESI) or paper spray, a direct analysis method that has been applied to the direct analysis of dried blood spots and other complex samples. We found that FAIMS was capable of separating the three opiate structural isomers using both H-ESI and paper spray as the ionization source.

  1. Isolation and Metabolic Characterization of a Pseudomonas stutzeri Mutant Able To Grow on the Three Isomers of Xylene (United States)

    Di, Le; Accarino, M.; Bolognese, F.; Galli, E.; Barbieri, P.


    From an o-xylene-degrading Pseudomonas stutzeri strain (OX1), we previously isolated mutant M1, which had acquired the ability to grow on m-xylene and p-xylene but lost the ability to utilize the ortho isomer. From M1 cultures we have now isolated a revertant strain (R1) which grows on o-xylene and retains the ability to grow with the meta and para isomers regardless of the selective pressure applied. In P. stutzeri R1, o-xylene is degraded through two successive monooxygenations of the aromatic ring, while m-xylene and p-xylene catabolism proceeds through the progressive oxidation of a methyl substituent, although unquantifiable amounts of these two substrates are transformed into the corresponding dimethylphenols, which are not utilized for further growth. The two catabolic pathways are inducible by all three xylene isomers. PMID:16535677

  2. Separation and identification of indene–C70 bisadduct isomers (United States)

    Zhang, Bolong; Subbiah, Jegadesan; Jones, David J


    Summary Following an initial work on the isolation of a single geometric isomer from an indene–C70 bisadduct (IC70BA) mixture, we report the full fractionation and identification of the bisadduct species in the material. Eleven fractions of IC70BA isomers were separated by high-performance liquid chromatography. A number of fractions contained relatively pure isomer species and their configuration were deduced using a variety of analytical techniques including 1H and 13C NMR and UV–vis spectroscopy. The electrochemical properties and the organic solar cell device performance were investigated for fractions where a reasonable quantity of sample could be isolated. PMID:27340480

  3. Properties of neutron-rich hafnium high-spin isomers

    CERN Document Server

    Tungate, G; Walker, P M; Neyens, G; Billowes, J; Flanagan, K; Koester, U H; Litvinov, Y

    It is proposed to study highly-excited multi-quasiparticle isomers in neutron-rich hafnium (Z=72) isotopes. Long half-lives have already been measured for such isomers in the storage ring at GSI, ensuring their accessibility with ISOL production. The present proposal focuses on:\\\\ (i) an on-line experiment to measure isomer properties in $^{183}$Hf and $^{184}$Hf, and\\\\ (ii) an off-line molecular breakup test using REXTRAP, to provide Hf$^{+}$ beams for future laser spectroscopy and greater sensitivity for the future study of more neutron-rich isotopes.

  4. Studies of high-K isomers at TRIUMF-ISAC

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.B. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada); Walker, P.M. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada); Department of Physics, University of Surrey, Guildford, Surrey (United Kingdom); Chakrawarthy, R.S. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada); Austin, R.A.E. [Department of Physics and Astronomy, McMaster University, Hamilton, ON (Canada); Ball, G.C. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada); Carroll, J.J. [Department of Physics and Astronomy, Youngstown State University, Ohio (United States); Cunningham, E. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada); Finlay, P. [Department of Physics, University of Guelph, Guelph, ON (Canada); Garrett, P.E. [Lawrence Livermore National Laboratory, Livermore, California (United States); Grinyer, G.F. [Department of Physics, University of Guelph, Guelph, ON (Canada); Hackman, G. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada); Hyland, B. [Department of Physics, University of Guelph, Guelph, ON (Canada); Koopmans, K. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada); Department of Physics and Astronomy, McMaster University, Hamilton, ON (Canada); Kulp, W.D. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia (United States); Leslie, J.R. [Physics Department, Queen' s University, Kingston, ON (Canada); Phillips, A.A. [Department of Physics, University of Guelph, Guelph, ON (Canada); Propri, R. [Department of Physics and Astronomy, Youngstown State University, Ohio (United States); Regan, P.H. [Department of Physics, University of Surrey, Guildford, Surrey (United Kingdom); Sarazin, F. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada); Schumaker, M.A. [Department of Physics, University of Guelph, Guelph, ON (Canada); Scraggs, H.C. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada)] [and others


    The properties of high-K isomers have been investigated by measuring {gamma} rays from a source of the 31-year {sup 178}Hf{sup m2} isomer and from the decay of implanted {sup 178,179}Lu beams. Low-intensity transitions have been identified in the decay of {sup 178}Hf{sup m2}, demonstrating a consistent extension of K-hindrance systematics to higher multipolarities, and elucidating the spin-dependence of the mixing between the two K{sup {pi}} = 8{sup -} bands. A search is underway for new isomers in {sup 178,179}Lu and the preliminary results of the analysis are reported.

  5. Detection of Actinides via Nuclear Isomer De-Excitation

    Energy Technology Data Exchange (ETDEWEB)

    Francy, Christopher J. [Oregon State Univ., Corvallis, OR (United States)


    This dissertation discusses a data collection experiment within the Actinide Isomer Identification project (AID). The AID project is the investigation of an active interrogation technique that utilizes nuclear isomer production, with the goal of assisting in the interdiction of illicit nuclear materials. In an attempt to find and characterize isomers belonging to 235U and its fission fragments, a 232Th target was bombarded with a monoenergetic 6Li ion beam, operating at 45 MeV.

  6. High-K isomers in $^{176}$W and mechanisms of K-violation

    CERN Document Server

    Crowell, B; Blumenthal, D J; Freeman, S J; Lister, C J; Carpenter, M P; Henry, R G; Janssens, R V F; Khoo, T L; Lauritsen, T; Liang, Y; Soramel, F; Bearden, I G; Crowell, B; Chowdhury, P; Blumenthal, D J; Freeman, S J; Lister, C J; Carpenter, M P; Henry, R G; Janssens, R V F; Khoo, T L; Lauritsen, T; Liang, Y; Soramel, F; Bearden, I G


    An isomer, with t1/2 = 35 +- 10 ns and J, Kpi = 14, 14+, has been observed in the nucleus 176W using the reaction 150Nd(30Si,4n) at a beam energy of 133 MeV. The isomer exhibits an unusual pattern of decay in which the _majority_ of the flux proceeds directly to states with =0, bypassing available levels of intermediate K. This severe breakdown of normal K-selection rules in 176W is compared with recent observations of K-violation in neighboring nuclei, within the framework of proposed theoretical approaches. The available data on these K-violating decays seem to have a consistent explanation in models of K-mixing which include large-amplitude fluctuations of the nuclear shape.

  7. Purification of 2,6-Diisopropylnaphthalene by Static Melt Crystallization from a Mixture Containing Diisopropylnaphthalene Isomers

    Institute of Scientific and Technical Information of China (English)

    TIAN,Zheng-Hua; JIA,Hong-Min; ZHAO,Gui-Li; HU,Wei-Qi


    2,6-Diisopropylnaphthalene (2,6-DIPN), as the precursor of important monomer 2,6-naphthalene dicarboxylic acid, could be produced by the shape-selective isopropylation of naphthalene with propene resulting in an isomeric mixture having different alkylation levels. Since the boiling points of DIPNs were very close and the differences of melting points in-between isomers were quite distinctive, the static melt crystallization was applied to separate and purify 2,6-DIPN from its isomers. 2,6-DIPN with purity ≥99% was produced through a process of three stages:crystallization→sweating→melting. The phase diagram of 2,6-DIPN-2,7-DIPN binary system was plotted to optimize the temperature control of crystallization. By repeated crystallization of melts with different concentration levels, the yield of pure 2,6-DIPN could be enhanced to 87%. No solvent was necessary.

  8. Improvement of ISOM by using filter

    Directory of Open Access Journals (Sweden)

    Imen Chaabouni


    Full Text Available Image compression helps in storing the transmitted data in proficient way by decreasing its redundancy. This technique helps in transferring more digital or multimedia data over internet as it increases the storage space. It is important to maintain the image quality even if it is compressed to certain extent. Depend upon this the image compression is classified into two categories : lossy and lossless image compression. There are many lossy digital image compression techniques exists. Among this Incremental Self Organizing Map is a familiar one. The good pictures quality can be retrieved if image denoising technique is used for compression and also provides better compression ratio. Image denoising is an important pre-processing step for many image analysis and computer vision system. It refers to the task of recovering a good estimate of the true image from a degraded observation without altering and changing useful structure in the image such as discontinuities and edges. Many approaches have been proposed to remove the noise effectively while preserving the original image details and features as much as possible. This paper proposes a technique for image compression using Incremental Self Organizing Map (ISOM with Discret Wavelet Transform (DWT by applying filtering techniques which play a crucial role in enhancing the quality of a reconstructed image. The experimental result shows that the proposed technique obtained better compression ratio value.

  9. Complexation and coordination selectivities of the tetradentate ligand 7-[(2-hydroxy-5-sulfophenyl) azo]-8-hydroxyquinoline-5-sulfonic acid with Fe(II), Ni(II), Zn(II), Cd(II) and VO(IV)

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hu; Kai, Fumiaki; Hirohata, Masaaki; Nakamura, Masaaki; Matsuzaki, Susumu; Komori, Kenji; Tsunematsu, Yuriko [Kumamoto Univ. (Japan)


    The new title tetradentate ligand (SPAHQS), containing both phenylazo and 8-quinolinol fragments, was prepared. Proton-dissociation processes of the ligand and complexing equilibria with Fe(II), Ni(II), Zn(II), Cd(II), and VO(IV) were analyzed spectrophotometrically. Coordination modes of SPAHQS with these metal ions have been investigated by means of polarography and Raman spectroscopy in aqueous solution. It was established that the coordination selectivity of SPAHQS for such metal ions is mainly dependent on steric factors in the chelate ring formed, not on HSAB properties. 18 refs., 6 figs., 2 tabs.

  10. Syntheses, structures and selective dye adsorption of five formic-based coordination polymers prepared by in-situ hydrolysis of N, N‧-dimethylformamide (United States)

    Zhu, Zheng; Meng, Xiang-min; Zhang, Dong-mei; Zhang, Xia; Wang, Mei; Jin, Fan; Fan, Yu-hua


    Five functional coordination polymers (formic-based CPs) namely: {[Cu2(CHOO)3(bibp)2]·CHOO}n (1), {[Co2(CHOO)3(bibp)2]·NO3·H2O}n (2), {[Ni2(CHOO)3(bibp)2]·NO3·H2O}n (3) [Co(CHOO)2(bbibp)]n (4) and [Zn(CHOO)2(bbibp)]n (5) (bibp=4,4‧-bis(imidazolyl)biphenyl, bbibp=4,4‧-bis(benzoimidazo-1-yl)biphenyl) have been successfully hydrothermally synthesized using the in-situ hydrolysis of N, N‧-dimethylformamide (DMF) as the source of formate. All of these five polymers were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analysis. Complexes 1-3 have the similar three-dimensional 3D kag topological framework built from the bibp ligand as the support member between the neighboring formic planes. Both complexes 4 and 5 have the similar one-dimensional 1D linear chain which is further assembled into 3D supermolecular structure by C-H…O hydrogen bonds. The dyes adsorption experiments have also been investigated systematically. The results show that complexes 2 and 3 exhibit high selective adsorption ability towards anionic dyes in their aqueous solution. Moreover, complex 2 displays good reversibility in the process of the dyes adsorption-release. Meanwhile, the unusual blocking phenomenon was firstly observed when complex 2 was in MO/OIV aqueous solutions with different concentration.

  11. Carotenoids and their isomers: color pigments in fruits and vegetables. (United States)

    Khoo, Hock-Eng; Prasad, K Nagendra; Kong, Kin-Weng; Jiang, Yueming; Ismail, Amin


    Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as 'functional food ingredients'. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant colors of a variety of fruits and vegetables. Carotenoids extensively studied in this regard include β-carotene, lycopene, lutein and zeaxanthin. Coloration of fruits and vegetables depends on their growth maturity, concentration of carotenoid isomers, and food processing methods. This article focuses more on several carotenoids and their isomers present in different fruits and vegetables along with their concentrations. Carotenoids and their geometric isomers also play an important role in protecting cells from oxidation and cellular damages.

  12. Reelfoot and Lake Isom National Wildlife Refuges : Wildlife Inventory Plan (United States)

    US Fish and Wildlife Service, Department of the Interior — This wildlife inventory plan for Reelfoot and Lake Isom National Wildlife Refuges includes survey procedure forms that represent cost effective inventory of the...

  13. Carotenoids and Their Isomers: Color Pigments in Fruits and Vegetables

    Directory of Open Access Journals (Sweden)

    Yueming Jiang


    Full Text Available Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as ‘functional food ingredients’. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant colors of a variety of fruits and vegetables. Carotenoids extensively studied in this regard include β-carotene, lycopene, lutein and zeaxanthin. Coloration of fruits and vegetables depends on their growth maturity, concentration of carotenoid isomers, and food processing methods. This article focuses more on several carotenoids and their isomers present in different fruits and vegetables along with their concentrations. Carotenoids and their geometric isomers also play an important role in protecting cells from oxidation and cellular damages.

  14. Aromaticity of All Possible C26N2 Isomers

    Institute of Scientific and Technical Information of China (English)

    TANG,Ming-Hui; ABLIKIM,Kerim


    The aromaticity of all possible heterofullerenes C26N2 and C28 based on Td symmetry has been studied by means of the topological resonance energy and percentage topological resonance energy methods. The relationship between the aromaticity of the C26N2 isomers and the sites where nitrogen atoms dope at the C28 cage has been discussed. The calculation results show that the most stable isomer of C26N2 derivatives is formed by nitrogen atoms doping at the two tetrahedral vertices. C26N2 isomers are more stable than C28, but the C26N2-2 isomers are less stable than C4-28. The effect of nitrogen substitution on C28 stability was investigated by the topological charge stabilization rule.

  15. Separation of amyl alcohol isomers in ZIF-77

    NARCIS (Netherlands)

    Bueno-Perez, R.; Gutiérrez-Sevillano, J.J.; Dubbeldam, D.; Merkling, P.J.; Calero, S.


    The separation of pentanol isomer mixtures is shown to be very efficient using the nanoporous adsorbent zeolitic imidazolate framework ZIF-77. Through molecular simulations, we demonstrate that this material achieves a complete separation of linear from monobranchedand these from dibranchedisomers.

  16. Reelfoot/Lake Isom National Wildlife Refuge: Comprehensive Conservation Plan (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Reelfoot and Lake Isom NWRs for the next 15 years. This plan outlines the refuges'...

  17. Isomer spectroscopy of {sup 125,127}Cd

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, F. [Institut fuer Kernphysik, Universitaet Koeln (Germany); GSI, Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Gorska, M.; Grawe, H.; Pietri, S. [GSI, Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Caceres, L. [GSI, Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Departmento de Fisicia Teorica, Universidad Autonoma de Madrid (Spain); Jungclaus, A. [Departmento de Fisicia Teorica, Universidad Autonoma de Madrid (Spain); Pfuetzner, M. [IEP, Warsaw University, Warsaw (Poland); Regan, P.H; Podolyak, Z. [Department of Physics, University of Surrey, Guildford (United Kingdom); Rudolf, D. [Department of Physics, Lund University (Sweden)


    The results of investigations of isomeric decay in odd mass heavy Cd isotopes namely {sup 125,127}Cd are reported. To date information has been obtained on even mass heavy Cd isotopes and the systematics show evolution of single particle energies for them. The experiment was performed at GSI, Darmstadt to investigate the single particle level structure of odd mass heavy Cd isotopes. Nuclei of interest were produced in fragmentation reaction of {sup 136}Xe beam at energy 750MeV/u on a {sup 9}Be target of 4g/cm{sup 2} thickness. Selection of ions from unwanted reaction products and event by event identification was facilitated by FRagment Separator (FRS). Isomers populated in the reaction were implanted in a plastic catcher surrounded by 15 Ge cluster detectors from RISING array to detect gamma radiations. Level schemes based on the intensity balance and life time information were constructed for the first time for these nuclei. Comparison of the experimental results with shell model calculation are discussed.

  18. Reactivity and selectivity differences between catecholate and catechothiolate Ru complexes. Implications regarding design of stereoselective olefin metathesis catalysts. (United States)

    Khan, R Kashif M; Torker, Sebastian; Hoveyda, Amir H


    The origins of the unexpected finding that Ru catechothiolate complexes, in contrast to catecholate derivatives, promote exceptional Z-selective olefin metathesis reactions are elucidated. We show that species containing a catechothiolate ligand, unlike catecholates, preserve their structural integrity under commonly used reaction conditions. DFT calculations indicate that, whereas alkene coordination is the stereochemistry-determining step with catecholate complexes, it is through the metallacyclobutane formation that the identity of the major isomer is determined with catechothiolate systems. The present findings suggest that previous models for Z selectivity, largely based on steric differences, should be altered to incorporate electronic factors as well.

  19. Regiospecific Distribution of trans-Octadecenoic Acid Positional Isomers in Triacylglycerols of Partially Hydrogenated Vegetable Oil and Ruminant Fat. (United States)

    Yoshinaga, Kazuaki; Kawamura, Yoshinori; Kitayama, Takashi; Nagai, Toshiharu; Mizobe, Hoyo; Kojima, Koichi; Watanabe, Yomi; Sato, Shinichi; Beppu, Fumiaki; Gotoh, Naohiro


    It is revealed that binding position of fatty acid in triacylglycerol (TAG) deeply relates to the expression of its function. Therefore, we investigated the binding positions of individual trans-octadecenoic acid (trans-C18:1) positional isomers, known as unhealthy fatty acids, on TAG in partially hydrogenated canola oil (PHCO), milk fat (MF), and beef tallow (BT). The analysis was carried out by the sn-1(3)-selective transesterification of Candida antarctica Lipase B and by using a highly polar ionic liquid capillary column for gas chromatography-flame ionization detection. Trans-9-C18:1, the major trans-C18:1 positional isomer, was selectively located at the sn-2 position of TAG in PHCO, although considerable amounts of trans-9-C18:1 were also esterified at the sn-1(3) position. Meanwhile, trans-11-C18:1, the major isomer in MF and BT, was preferentially located at the sn-1(3) position. These results revealed that the binding position of trans-C18:1 positional isomer varies between various fats and oils.

  20. Anaerobic biodegradability of phthalic acid isomers and related compounds. (United States)

    Kleerebezem, R; Pol, L W; Lettinga, G


    All three phthalic acid isomers (ortho, meta and para benzene dicarboxylic acid) are produced in massive amounts, and used in the chemical industry as plasticizers or for the production of polyester. Wastestreams generated during the production of phthalate isomers generally contain high concentrations of aromatic acids. To study the potential biodegradability of these primarily anthropogenic compounds in anaerobic bioreactors, biodegradability studies were performed. Compounds tested were benzoate, ortho-phthalate, isophthalate, terephthalate, dimethyl phthalate, dimethyl terephthalate, para-toluate and para-xylene. Seed materials tested were two types of granular sludge and digested sewage sludge. It was found that all phthalate isomers and their corresponding dimethyl-esters, could be completely mineralized by all seed materials studied. Lag phases required for 50% degradation of these compounds, ranged from 17 to 156 days. The observed degradation curves could be explained by growth of an initially small amount of organisms in the inoculum with the specific ability to degrade one phthalate isomer. The observed order in the length of the lag phases for the phthalate isomers is: phthalate terephthalate terephthalate was found to be fermentation of the phthalate isomer. Para-toluate was degraded only by digested sewage sludge after a lag phase of 425 days. The observed degradation rates of this compound were very low. No mineralization of para-xylene was observed. In general, the differences in the lag phases between different seed materials were relatively small. These results indicate that the time needed for the start-up of anaerobic bioreactors treating wastewaters containing phthalic acid isomers, depends little on the microbial composition of the seed material applied, but may take several months.


    CERN Multimedia

    A. Ball

    Overview From a technical perspective, CMS has been in “beam operation” state since 6th November. The detector is fully closed with all components operational and the magnetic field is normally at the nominal 3.8T. The UXC cavern is normally closed with the radiation veto set. Access to UXC is now only possible during downtimes of LHC. Such accesses must be carefully planned, documented and carried out in agreement with CMS Technical Coordination, Experimental Area Management, LHC programme coordination and the CCC. Material flow in and out of UXC is now strictly controlled. Access to USC remains possible at any time, although, for safety reasons, it is necessary to register with the shift crew in the control room before going down.It is obligatory for all material leaving UXC to pass through the underground buffer zone for RP scanning, database entry and appropriate labeling for traceability. Technical coordination (notably Stephane Bally and Christoph Schaefer), the shift crew and run ...

  2. A new high-spin isomer in {sup 195}Bi

    Energy Technology Data Exchange (ETDEWEB)

    Roy, T.; Mukherjee, G.; Rana, T.K.; Bhattacharya, Soumik; Asgar, Md.A.; Bhattacharya, C.; Bhattacharya, S.; Bhattacharyya, S.; Pai, H. [Variable Energy Cyclotron Centre, Kolkata (India); Madhavan, N.; Bala, I.; Gehlot, J.; Gurjar, R.K.; Jhingan, A.; Kumar, R.; Muralithar, S.; Nath, S.; Singh, R.P.; Varughese, T. [Inter University Acclerator Centre, New Delhi (India); Basu, K.; Bhattacharjee, S.S.; Ghugre, S.S.; Raut, R.; Sinha, A.K. [UGC-DAE-CSR Kolkata Centre, Kolkata (India); Palit, R. [Tata Institute of Fundamental Research, Department of Nuclear and Atomic Physics, Mumbai (India)


    A new high-spin isomer has been identified in {sup 195}Bi at the focal plane of the HYbrid Recoil mass Analyser (HYRA) used in the gas-filled mode. The fusion evaporation reactions {sup 169}Tm ({sup 30}Si, x n) {sup 193,} {sup 195}Bi were used with the beam energies on targets of 168 and 146MeV for 6n and 4n channels, respectively. The evaporation residues, separated from the fission fragments, and their decays were detected at the focal plane of HYRA using MWPC, Si-Pad and clover HPGe detectors. The half-life of the new isomer in {sup 195}Bi has been measured to be 1.6(1) μs. The configuration of the new isomer has been proposed and compared with the other isomers in this region. The Total Routhian Surface (TRS) calculations for the three-quasiparticle configurations corresponding to the new isomer suggest an oblate deformation for this isomeric state. The same calculations for different configurations in {sup 195}Bi and for the even-even {sup 194}Pb core indicate that the proton i{sub 13/2} orbital has a large shape driving effect towards oblate shape in these nuclei. (orig.)

  3. Direct observation of long-lived isomers in $^{212}$Bi

    CERN Document Server

    Chen, L; Geissel, H; Litvinov, Yu A; Beckert, K; Beller, P; Bosch, F; Boutin, D; Caceres, L; Carroll, J J; Cullen, D M; Cullen, I J; Franzke, B; Gerl, J; Górska, M; Jones, G A; Kishada, A; Knöbel, R; Kozhuharov, C; Kurcewicz, J; Litvinov, S A; Liu, Z; Mandal, S; Montes, F; Münzenberg, G; Nolden, F; Ohtsubo, T; Patyk, Z; Plaß, W R; Podolyák, Zs; Rigby, S; Saito, N; Saito, T; Scheidenberger, C; Simpson, E C; Shindo, M; Steck, M; Sun, B; Williams, S J; Weick, H; Winkler, M; Wollersheim, H -J; Yamaguchi, T


    Long-lived isomers in 212Bi have been studied following 238U projectile fragmentation at 670 MeV per nucleon. The fragmentation products were injected as highly charged ions into the GSI storage ring, giving access to masses and half-lives. While the excitation energy of the first isomer of 212Bi was confirmed, the second isomer was observed at 1478(30) keV, in contrast to the previously accepted value of >1910 keV. It was also found to have an extended Lorentz-corrected in-ring halflife >30 min, compared to 7.0(3) min for the neutral atom. Both the energy and half-life differences can be understood as being due a substantial, though previously unrecognised, internal decay branch for neutral atoms. Earlier shell-model calculations are now found to give good agreement with the isomer excitation energy. Furthermore, these and new calculations predict the existence of states at slightly higher energy that could facilitate isomer de-excitation studies.

  4. Effects of butanol isomers on dipalmitoylphosphatidylcholine bilayer membranes. (United States)

    Reeves, Megan D; Schawel, Adam K; Wang, Weidong; Dea, Phoebe


    Differential scanning calorimetry and (31)P-NMR were used to study the effects of butanol isomers on the thermotropic phase behavior of dipalmitoylphosphatidylcholine (DPPC) bilayers. The threshold concentration for the onset of interdigitation for each isomer was determined by the disappearance of the pretransition and the onset of a large hysteresis between the heating and cooling scans of the gel-to-liquid main transition. The threshold concentration was found to correlate with increased solubility of the isomers in the aqueous phase, led by tert-butanol. However, as the solution concentration of tert-butanol increased, there was an abrupt shrinking of the hysteresis, initially with well-resolved shoulder peaks indicating mixed phases. The eventual disappearance of the shoulder peaks was correlated with a breakdown of the multilamellar structure identified using (31)P-NMR.


    CERN Multimedia

    A. Ball


    Operational Experience At the end of the first full-year running period of LHC, CMS is established as a reliable, robust and mature experiment. In particular common systems and infrastructure faults accounted for <0.6 % CMS downtime during LHC pp physics. Technical operation throughout the entire year was rather smooth, the main faults requiring UXC access being sub-detector power systems and rack-cooling turbines. All such problems were corrected during scheduled technical stops, in the shadow of tunnel access needed by the LHC, or in negotiated accesses or access extensions. Nevertheless, the number of necessary accesses to the UXC averaged more than one per week and the technical stops were inevitably packed with work packages, typically 30 being executed within a few days, placing a high load on the coordination and area management teams. It is an appropriate moment for CMS Technical Coordination to thank all those in many CERN departments and in the Collaboration, who were involved in CMS techni...

  6. Coordination of Conditional Poisson Samples

    Directory of Open Access Journals (Sweden)

    Grafström Anton


    Full Text Available Sample coordination seeks to maximize or to minimize the overlap of two or more samples. The former is known as positive coordination, and the latter as negative coordination. Positive coordination is mainly used for estimation purposes and to reduce data collection costs. Negative coordination is mainly performed to diminish the response burden of the sampled units. Poisson sampling design with permanent random numbers provides an optimum coordination degree of two or more samples. The size of a Poisson sample is, however, random. Conditional Poisson (CP sampling is a modification of the classical Poisson sampling that produces a fixed-size πps sample. We introduce two methods to coordinate Conditional Poisson samples over time or simultaneously. The first one uses permanent random numbers and the list-sequential implementation of CP sampling. The second method uses a CP sample in the first selection and provides an approximate one in the second selection because the prescribed inclusion probabilities are not respected exactly. The methods are evaluated using the size of the expected sample overlap, and are compared with their competitors using Monte Carlo simulation. The new methods provide a good coordination degree of two samples, close to the performance of Poisson sampling with permanent random numbers.

  7. Theoretical Study of the Diastereofacial Isomers of Aldrin and Dieldrin

    Directory of Open Access Journals (Sweden)

    Zoran Zdravkovski


    Full Text Available The Diels-Alder reaction of hexachlorocyclopentadiene with norbornadiene givesaldrin but theoretically three other diastereofacial isomers are possible. On oxidation theseisomers can generate eight adducts one of which is known as dieldrin. All these, as well asthe corresponding reactions with hexafluorocyclopenadiene were studied by semiempirical(AM1 and PM3 and hybrid density functional (B3LYP methods. Besides the energy levels,the transition states were calculated for the reactions leading to the diastereofacial isomers ofaldrin, which indicate that aldrin is the favored product of the reaction both fromthermodynamic and kinetic point of view.

  8. Characterization of vanadium compounds in selected crudes. II. Electron paramagnetic resonance studies of the first coordination spheres in porphyrin and non-porphyrin fractions

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, J.G.; Biggs, W.R.; Fetzer, J.C.


    The authors applied electron paramagnetic resonance spectroscopy (EPR) to heavy petroleum fractions to characterize the first coordination sphere around the vanadyl +2 ion. The fractions were generated using a modified porphyrin extraction procedure. For the residual oil from the extraction, which contains the non-porphyrin metals, the first coordination sphere was dominated by 4N and N O 2S for Boscan, Beta, Morichal, and Arabian Heavy crudes. Maya had distinctively different parameters. These findings are significant for determining the overall structure of metal-containing compounds in heavy crude oils. They discuss the difference between the porphyrin and non-porphyrin behavior, possible biogenic precursors, and some process implications. 59 references, 1 figure, 2 tables.

  9. Design and structure analysis of artificial metalloproteins: selective coordination of His64 to copper complexes with square-planar structure in the apo-myoglobin scaffold. (United States)

    Abe, Satoshi; Ueno, Takafumi; Reddy, Pattubala A N; Okazaki, Seiji; Hikage, Tatsuo; Suzuki, Atsuo; Yamane, Takashi; Nakajima, Hiroshi; Watanabe, Yoshihito


    apo-Myoglobin (apo-Mb) was reconstituted with three copper complexes: CuII(Sal-Phe) (1; Sal-Phe = N-salicylidene-L-phenylalanato), CuII(Sal-Leu) (2; Sal-Leu = N-salicylidene-L-leucinato), and CuII(Sal-Ala) (3; Sal-Ala = N-salicylidene-L-alanato). The crystal structures of 1.apo-Mb (1.65 Angstrom resolution) and 2.apo-Mb (1.8 Angstrom resolution) show that the coordination geometry around the CuII atom in apo-Mb is distorted square-planar with tridentate Sal-X and a Nepsilon atom of His64 in the apo-Mb cavity and the plane of these copper complexes is perpendicular to that of heme. These results suggest that the apo-Mb cavity can hold metal complexes with various coordination geometries.

  10. Coordination Capacity

    CERN Document Server

    Cuff, Paul; Cover, Thomas


    We develop elements of a theory of cooperation and coordination in networks. Rather than considering a communication network as a means of distributing information, or of reconstructing random processes at remote nodes, we ask what dependence can be established among the nodes given the communication constraints. Specifically, in a network with communication rates between the nodes, we ask what is the set of all achievable joint distributions p(x1, ..., xm) of actions at the nodes on the network. Several networks are solved, including arbitrarily large cascade networks. Distributed cooperation can be the solution to many problems such as distributed games, distributed control, and establishing mutual information bounds on the influence of one part of a physical system on another.

  11. Isomer-specific analysis of nonylphenols with estrogenic activity and their distribution in aquatic environment in relation to endocrine disrupters

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y.S.; Katase, T.; Inoue, T. [Nihon Univ., Fujisawa, Kanagawa (Japan). College of Bioresource Sciences; Horii, Y.; Yamashita, N. [National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki (Japan); Makino, M.; Uchiyama, T.; Fujimoto, Y. [Nihon Univ., Chiba (Japan). College of Pharmacy


    The effect of estrogen-exposure on levels of a larval storage protein of Balanus amphitrite, cypris major protein (CMP), which is related to barnacle vitellin, has been examined at low concentrations (0.01-1.0 {mu}g/l) of 4-nonylphenol (NP) and 17{beta}-estradiol (E2) (1.0 {mu}g/l) from egg hatching until the nauplius cypris stage. Eventually, the exposure to 0.01 {mu}g/l of NP led to a ca. 50% increase in the optical density of the CMP. There are theoretically ca. 170 kinds of isomers of NP, based on the structure of the nonyl side chain in NP. We fractionated a commercial NP by high performance liquid chromatography (HPLC) to give six fractions (Fr. 1- Fr. 6). Fr. 3 - Fr. 5 were further separated to afford 14 fractions by using gas chromatograph equipped with a preparative fraction collector (GC-PFC) and 11 NP isomers were identified by gas chromatograph equipped with mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR). The chemical structures of 11 isomers (NP1 to NP14) were characterized and estrogenicities of the selected isomers were tested in recombinant yeast screen system. The 4-(1,1-dimethyl-2-ethyl-pentyl)- phenol (NP7) was found to exhibit the highest estrogenic activity corresponding to 1.9 x 10{sup -3} that of E2. The NP4 and 6 were structurally in diastereomer. The individual isomer of NP in aquatic samples taken from Ariake Sea and Tokyo, Japan was analyzed by steam distillation extraction in the present study.

  12. Isomer and decay studies for the rp process at IGISOL

    Energy Technology Data Exchange (ETDEWEB)

    Kankainen, A.; Elomaa, V.V.; Eronen, T.; Hakala, J.; Jokinen, A.; Karvonen, P.; Reponen, M.; Rissanen, J.; Saastamoinen, A.; Weber, C.; Aeystoe, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Novikov, Yu.N.; Batist, L. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Oinonen, M. [University of Helsinki, Dating Laboratory, Helsinki (Finland); Vorobjev, G. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)


    This article reviews the decay studies of neutron-deficient nuclei within the mass region A=56-100 performed at the Ion-Guide Isotope Separator On-Line (IGISOL) facility in the University of Jyvaeskylae over last 25 years. Development from He-jet measurements to on-line mass spectrometry, and eventually to atomic mass measurements and post-trap spectroscopy at IGISOL, has yielded studies of around 100 neutron-deficient nuclei over the years. The studies form a solid foundation to astrophysical rp -process path modelling. The focus is on isomers studied either via spectroscopy or via Penning-trap mass measurements. The review is complemented with recent results on the ground and isomeric states of {sup 90}Tc. The excitation energy of the low-spin isomer in {sup 90}Tc has been measured as E{sub x}=144.1(17) keV with JYFLTRAP double Penning trap and the ground state of {sup 90}Tc has been confirmed to be the (8{sup +}) state with a half-life of T{sub 1/2}=49.2(4) s. Finally, the mass-excess results for the spin-gap isomers {sup 53}Co{sup m} and {sup 95}Pd{sup m} and implications from the JYFLTRAP mass measurements for the (21{sup +}) isomer in {sup 94}Ag are discussed. (orig.)

  13. The molecular properties of nitrobenzanthrone isomers and their mutagenic activities. (United States)

    Ostojić, Bojana D; Stanković, Branislav; Ðorđević, Dragana S


    The mutagenic activity of five mono-substituted nitrobenzanthrones (NBA) has been determined in the Ames assay (Takamura-Enya et al., 2006). In the present study, a theoretical investigation of the electronic properties of all mono-substituted NBA isomers and their relation to mutagenic activity are presented. Equilibrium geometries, vertical ionization potentials (VIP), vertical electron affinities (VEA), relative energies, dipole moments and electronic dipole polarizabilities, and the IR and Raman spectra of NBA isomers calculated by Density Functional Theory (DFT) methods are presented. The position of the nitro group affects the spectral features of the IR and Raman spectra of the NBA isomers. The results show that a good linear relationship exists between the summation of Raman activities (∑ARaman) over all the 3N-6 vibrational modes and the mutagenic activity of the NBA isomers in Salmonella typhimurium strains. The spectroscopic results suggest that the unknown mutagenic activities of 4-NBA, 5-NBA, 6-NBA, 8-NBA and 10-NBA are predicted to follow the order 4-NBA>10-NBA>5-NBA>8-NBA>6-NBA. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. High Spin Isomers and Super Heavy Elements (SHE) Synthesis (United States)

    Popescu, Domitian G.


    To get closer to the SHE-Island the new radioactive beams are proposed for future fusion reaction. We suggest something different : to use the advantage of High Spin Isomer States, by tacking into account the importance of the G (spin-isospin cupling) suggested by Ripka 1.

  15. Identification of position isomers by energy-resolved mass spectrometry. (United States)

    Menachery, Sunil Paul M; Laprévote, Olivier; Nguyen, Thao P; Aravind, Usha K; Gopinathan, Pramod; Aravindakumar, Charuvila T


    This study reports an energy-resolved mass spectrometric (ERMS) strategy for the characterization of position isomers derived from the reaction of hydroxyl radicals ((●)OH) with diphenhydramine (DPH) that are usually hard to differentiate by other methods. The isomer analogues formed by (●)OH attack on the side chain of DPH are identified with the help of a specific fragment ion peak (m/z 88) in the collision-induced dissociation (CID) spectrum of the protonated molecule. In the negative ion mode, the breakdown curves of the deprotonated molecules show an order of stability (supported by density functional theory (DFT) calculations) ortho > meta > para of the positional isomers formed by the hydroxylation of the aromatic ring. The gas phase stability of the deprotonated molecules [M - H](-) towards the benzylic cleavage depends mainly on the formation of intramolecular hydrogen bonds and of the mesomeric effect of the phenol hydroxyl. The [M - H](-) molecules of ortho and meta isomers result a peak at m/z 183 with notably different intensities because of the presence/absence of an intramolecular hydrogen bonding between the OH group and C9 protons. The ERMS approach discussed in this report might be an effective replacement for the conventional methods that requires very costly and time-consuming separation/purification methods along with the use of multi-spectroscopic methods.

  16. Generalized seniority states and isomers in tin isotopes (United States)

    Jain, Ashok Kumar; Maheshwari, Bhoomika


    Isomeric studies in neutron-rich nuclei are a powerful tool for exploring structure at the nuclear extremes. In this paper we discuss the systematic features of the excitation energies and transition probabilities of Sn isotopes in the region N = 50-82 and present their basic understanding in terms of generalized seniority. We further use generalized seniority as a probe to explore the neutron-rich {6}+ seniority isomers in 134-138Sn, and to validate the neutron single-particle energies beyond N = 82. We show that these isomers behave as generalized seniority isomers, where the so-called anomalous {{B}}(E2) behavior of the {6}+ isomer in 136Sn may be naturally explained. We support these results by shell model calculations, where the latest neutron single-particle energies of the N = 82-126 region have been used, and the i13/2 neutron single-particle energy has been suitably modified in the renormalized charge-dependent Bonn interaction. This entails a possible new subshell closure at N = 112 due to the suggested higher location of the i13/2 neutron orbital, also consistent with the choice of orbitals in the generalized seniority scheme. However, a small reduction in the f7/2 two-body matrix elements is still required in the shell model calculations to consistently reproduce the experimental level energies as well as the transition probabilities in 134-138Sn isotopes.

  17. Shape Isomer in 236U Populated by Thermal Neutron Capture

    DEFF Research Database (Denmark)

    Andersen, Verner; Christensen, Carl Jørgen; Borggreen, J.


    The 116 ns shape isomer in 236U was populated by thermal neutron capture. Conversion electrons and X-rays were detected simultaneously in delayed coincidence with fission. The ratio of delayed to prompt fission was measured with the result, σIIf/σf = (1.0±0.2) × 10−5. A branching of the isomeric...

  18. Thorium isomer for radiative emission of neutrino pair

    CERN Document Server

    Sasao, N; Yoshimi, A; Yoshimura, K; Yoshimura, M


    It is proposed to use the isomer ionic ground state $^{229m}$Th$^{4+}$ embedded in transparent crystals for precision determination of unknown neutrino parameters. Isolation from solid environment of the proposed nuclear process, along with available experimental techniques of atomic physics, has a great potentiality for further study.

  19. Synthesis and comparative biological evaluation of L- and D-isomers of {sup 18}F-labeled fluoroalkyl phenylalanine derivatives as tumor imaging agents

    Energy Technology Data Exchange (ETDEWEB)

    Wang Limin [Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104 (United States); Lieberman, Brian P.; Ploessl, Karl; Qu Wenchao [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Kung, Hank F., E-mail: [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104 (United States)


    Introduction: L-Amino acid-based tracers have established their important role as tumor metabolic imaging agents. Recently, a number of studies demonstrated that D-amino acids may have improved imaging properties than their corresponding L-isomers. We synthesized and evaluated the D-isomer of a new phenylalanine derivative, p-(2-[{sup 18}F]fluoroethyl)-phenylalanine ([{sup 18}F]FEP), in comparison to its L-isomer and previously reported the L- and D-isomers of O-(2-[{sup 18}F]fluoroethyl)-tyrosine ([{sup 18}F]FET). Methods: L- and D-Isomers of [{sup 18}F]FET and [{sup 18}F]FEP were successfully synthesized via a rapid and efficient two-step nucleophilic fluorination and deprotection reaction. In vitro studies were carried out in 9L glioma cells. In in vivo studies, Fisher 344 rats bearing the 9L tumor model were used. Results: L- and D-Isomers of {sup 18}F-fluoroalkyl tyrosine and phenylalanine derivatives were efficiently labeled with high enantiomeric purity (>95%), good yield (11-45%) and high specific activity (21-75 GBq/{mu}mol). D-[{sup 18}F]FEP showed a similar linear time-dependent uptake as D-[{sup 18}F]FET, while their corresponding L-isomers had much faster and higher uptake (4.3- to 16.0-fold at maximum uptake). The maximum uptake of the new compounds, L- and D-[{sup 18}F]FEP, was 1.4- and 5.2-fold of that reported for L- and D-[{sup 18}F]FET, respectively. Transport characterization studies indicated that both L- and D-[{sup 18}F]FEP were selective substrates for system L. While L-[{sup 18}F]FEP exhibited preference towards one subtype of system L, LAT1, D-[{sup 18}F]FEP did not exhibit the same preference. Small animal PET imaging studies showed that both L- and D-[{sup 18}F]FEP had higher uptake in 9L tumor compared to surrounding tissues, but D-isomer had lower tumor-to-muscle ratio in comparison with its L-isomer. Conclusion: Both L- and D-[{sup 18}F]FEP are substrates for system L amino acid transporter with different preference toward its

  20. FY2011 Annual Report for the Actinide Isomer Detection Project

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Glen A.; Francy, Christopher J.; Ressler, Jennifer J.; Erikson, Luke E.; Tatishvili, Gocha; Hatarik, R.


    This project seeks to identify a new signature for actinide element detection in active interrogation. This technique works by exciting and identifying long-lived nuclear excited states (isomers) in the actinide isotopes and/or primary fission products. Observation of isomers in the fission products will provide a signature for fissile material. For the actinide isomers, the decay time and energy of the isomeric state is unique to a particular isotope, providing an unambiguous signature for SNM. This project entails isomer identification and characterization and neutron population studies. This document summarizes activities from its third year - completion of the isomer identification characterization experiments and initialization of the neutron population experiments. The population and decay of the isomeric state in 235U remain elusive, although a number of candidate gamma rays have been identified. In the course of the experiments, a number of fission fragment isomers were populated and measured [Ressler 2010]. The decays from these isomers may also provide a suitable signature for the presence of fissile material. Several measurements were conducted throughout this project. This report focuses on the results of an experiment conducted collaboratively by PNNL, LLNL and LBNL in December 2010 at LBNL. The measurement involved measuring the gamma-rays emitted from an HEU target when bombarded with 11 MeV neutrons. This report discussed the analysis and resulting conclusions from those measurements. There was one strong candidate, at 1204 keV, of an isomeric signature of 235U. The half-life of the state is estimated to be 9.3 {mu}s. The measured time dependence fits the decay time structure very well. Other possible explanations for the 1204-keV state were investigated, but they could not explain the gamma ray. Unfortunately, the relatively limited statistics of the measurement limit, and the lack of understanding of some of the systematic of the experiment, limit


    CERN Multimedia

    C. Delaere


    Since the LHC ceased operations in February, a lot has been going on at Point 5, and Run Coordination continues to monitor closely the advance of maintenance and upgrade activities. In the last months, the Pixel detector was extracted and is now stored in the pixel lab in SX5; the beam pipe has been removed and ME1/1 removal has started. We regained access to the vactank and some work on the RBX of HB has started. Since mid-June, electricity and cooling are back in S1 and S2, allowing us to turn equipment back on, at least during the day. 24/7 shifts are not foreseen in the next weeks, and safety tours are mandatory to keep equipment on overnight, but re-commissioning activities are slowly being resumed. Given the (slight) delays accumulated in LS1, it was decided to merge the two global runs initially foreseen into a single exercise during the week of 4 November 2013. The aim of the global run is to check that we can run (parts of) CMS after several months switched off, with the new VME PCs installed, th...


    CERN Multimedia

    Christophe Delaere


    The focus of Run Coordination during LS1 is to monitor closely the advance of maintenance and upgrade activities, to smooth interactions between subsystems and to ensure that all are ready in time to resume operations in 2015 with a fully calibrated and understood detector. After electricity and cooling were restored to all equipment, at about the time of the last CMS week, recommissioning activities were resumed for all subsystems. On 7 October, DCS shifts began 24/7 to allow subsystems to remain on to facilitate operations. That culminated with the Global Run in November (GriN), which   took place as scheduled during the week of 4 November. The GriN has been the first centrally managed operation since the beginning of LS1, and involved all subdetectors but the Pixel Tracker presently in a lab upstairs. All nights were therefore dedicated to long stable runs with as many subdetectors as possible. Among the many achievements in that week, three items may be highlighted. First, the Strip...

  3. Isomer-specific regulation of metabolism and PPARγ signaling by CLA in human preadipocytes


    Brown, J. Mark; Boysen, Maria Sandberg; Jensen, Søren Skov; Morrison, Ron F.; Storkson, Jayne; Lea-Currie, Renee; Pariza, Michael; Mandrup, Susanne; McIntosh, Michael K.


    Trans-10,cis-12 conjugated linoleic acid (CLA) has previously been shown to be the CLA isomer responsible for CLA-induced reductions in body fat in animal models, and we have shown that this isomer, but not the cis-9,trans-11 CLA isomer, specifically decreased triglyceride (TG) accumulation in primary human adiopcytes in vitro. Here we investigated the mechanism behind the isomer-specific, CLA-mediated reduction in TG accumulation in differentiating human preadipocytes. Trans-10,cis-12 CLA de...

  4. Supramolecular Isomers of Metal-Organic Frameworks Derived from a Partially Flexible Ligand with Distinct Binding Motifs

    KAUST Repository

    Abdul Halim, Racha Ghassan


    Three novel metal-organic frameworks (MOFs) were isolated upon reacting a heterofunctional ligand 4 (pyrimidin-5 yl)benzoic acid (4,5-pmbc) with mixed valence Cu(I,II) under solvothermal conditions. X-ray crystal structural analysis reveals that the first compound is a layered structure composed of one type of inorganic building block, dinuclear paddlewheel [Cu2(O2C–)4], which are linked through 4,5-pmbc ligands. The two other supramolecular isomers are composed of the same Cu(II) dinuclear paddlewheel and a dinuclear Cu2I2 cluster, which are linked via the 4,5-pmbc linkers to yield two different 3-periodic frameworks with underlying topologies related to lvt and nbo. The observed structural diversity in these structures is due to the distinct coordination modes of the two coordinating moieties (the carboxylate group on the phenyl ring and the N-donor atoms from the pyrimidine moiety).

  5. Theoretical study on the structures, stabilities and electronic properties of S2 O5 2- isomers in the gas and solution phases (United States)

    Abedi, Mostafa; Vahedpour, Morteza; Farnia, Solaleh; Farrokhpour, Hossein


    Different theoretical levels of theory including B3LYP/6-311 + G(3df,3pd), MP2/6-311 + G(3df,3pd), QCISD/6-311 + G(d,p), CBS-QB3 and CCSD(T)/6-311 + (d,p)//B3LYP/6-311 + G(3df,3pd) have been employed to determine the structures, relative stabilities, electronic properties and thermochemistry of the selected ? isomers in the gas phase and aqueous solution. Atoms in molecules (AIM) method and natural bonding orbital (NBO) were used to characterize the origin of atomic bonds. The NBO and AIM calculations showed that the strength of S-O and S-S bonds in the (O3SSO2)2-, (O2SOSO2)2- and (OSOSO3)2- isomer are relatively weak and go toward dissociation to form ? , ? , SO- and ? radical anions. For more confirmation, the dissociation equilibrium constant (K diss) of each isomer were calculated at 298 K and showed that by increasing the dielectric constant of the solvent, the stability of the isomer increases. Based on these result, the ? isomers are considerably unstable and dissociate in the gas phase compared with solution.

  6. Driven evolution of a constitutional dynamic library of molecular helices toward the selective generation of [2 x 2] gridlike arrays under the pressure of metal ion coordination. (United States)

    Giuseppone, Nicolas; Schmitt, Jean-Louis; Lehn, Jean-Marie


    Constitutional dynamics, self-assembly, and helical-folding control are brought together in the efficient Sc(OTf)3/microwave-catalyzed transimination of helical oligohydrazone strands, yielding highly diverse dynamic libraries of interconverting constituents through assembly, dissociation, and exchange of components. The transimination-type mechanism of the ScIII-promoted exchange, as well as its regioselectivity, occurring only at the extremities of the helical strands, allow one to perform directional terminal polymerization/depolymerization processes when starting with dissymmetric strands. A particular library is subsequently brought to express quantitatively [2 x 2] gridlike metallosupramolecular arrays in the presence of ZnII ions by component recombination generating the correct ligand from the dynamic set of interconverting strands. This behavior represents a process of driven evolution of a constitutional dynamic chemical system under the pressure (coordination interaction) of an external effector (metal ions).

  7. A CD36-related Transmembrane Protein Is Coordinated with an Intracellular Lipid-binding Protein in Selective Carotenoid Transport for Cocoon Coloration*


    Sakudoh, Takashi; Iizuka, Tetsuya; Narukawa, Junko; Sezutsu, Hideki; Kobayashi, Isao; Kuwazaki, Seigo; Banno, Yutaka; Kitamura, Akitoshi; Sugiyama, Hiromu; Takada, Naoko; Fujimoto, Hirofumi; Kadono-Okuda, Keiko; Mita, Kazuei; Tamura, Toshiki; Yamamoto, Kimiko


    The transport pathway of specific dietary carotenoids from the midgut lumen to the silk gland in the silkworm, Bombyx mori, is a model system for selective carotenoid transport because several genetic mutants with defects in parts of this pathway have been identified that manifest altered cocoon pigmentation. In the wild-type silkworm, which has both genes, Yellow blood (Y) and Yellow cocoon (C), lutein is transferred selectively from the hemolymph lipoprotein to the silk gland cells where it...

  8. Assigning Peptide Disulfide Linkage Pattern Among Regio-Isomers via Methoxy Addition to Disulfide and Tandem Mass Spectrometry (United States)

    Durand, Kirt L.; Tan, Lei; Stinson, Craig A.; Love-Nkansah, Chasity B.; Ma, Xiaoxiao; Xia, Yu


    Pinpointing disulfide linkage pattern is critical in the characterization of proteins and peptides consisting of multiple disulfide bonds. Herein, we report a method based on coupling online disulfide modification and tandem mass spectrometry (MS/MS) to distinguish peptide disulfide regio-isomers. Such a method relies on a new disulfide bond cleavage reaction in solution, involving methanol as a reactant and 254 nm ultraviolet (UV) irradiation. This reaction leads to selective cleavage of a disulfide bond and formation of sulfenic methyl ester (-SOCH3) at one cysteine residue and a thiol (-SH) at the other. Under low energy collision-induced dissociation (CID), cysteine sulfenic methyl ester motif produces a signature methanol loss (-32 Da), allowing its identification from other possible isomeric structures such as S-hydroxylmethyl (-SCH2OH) and methyl sulfoxide (-S(O)-CH3). Since disulfide bond can be selectively cleaved and modified upon methoxy addition, subsequent MS2 CID of the methoxy addition product provides enhanced sequence coverage as demonstrated by the analysis of bovine insulin. More importantly, this reaction does not induce disulfide scrambling, likely due to the fact that radical intermediates are not involved in the process. An approach based on methoxy addition followed by MS3 CID has been developed for assigning disulfide linkage patterns in peptide disulfide regio-isomers. This methodology was successfully applied to characterizing peptide systems having two disulfide bonds and three disulfide linkage isomers: side-by-side, overlapped, and looped-within-a-loop configurations.

  9. Assigning Peptide Disulfide Linkage Pattern Among Regio-Isomers via Methoxy Addition to Disulfide and Tandem Mass Spectrometry (United States)

    Durand, Kirt L.; Tan, Lei; Stinson, Craig A.; Love-Nkansah, Chasity B.; Ma, Xiaoxiao; Xia, Yu


    Pinpointing disulfide linkage pattern is critical in the characterization of proteins and peptides consisting of multiple disulfide bonds. Herein, we report a method based on coupling online disulfide modification and tandem mass spectrometry (MS/MS) to distinguish peptide disulfide regio-isomers. Such a method relies on a new disulfide bond cleavage reaction in solution, involving methanol as a reactant and 254 nm ultraviolet (UV) irradiation. This reaction leads to selective cleavage of a disulfide bond and formation of sulfenic methyl ester (-SOCH3) at one cysteine residue and a thiol (-SH) at the other. Under low energy collision-induced dissociation (CID), cysteine sulfenic methyl ester motif produces a signature methanol loss (-32 Da), allowing its identification from other possible isomeric structures such as S-hydroxylmethyl (-SCH2OH) and methyl sulfoxide (-S(O)-CH3). Since disulfide bond can be selectively cleaved and modified upon methoxy addition, subsequent MS2 CID of the methoxy addition product provides enhanced sequence coverage as demonstrated by the analysis of bovine insulin. More importantly, this reaction does not induce disulfide scrambling, likely due to the fact that radical intermediates are not involved in the process. An approach based on methoxy addition followed by MS3 CID has been developed for assigning disulfide linkage patterns in peptide disulfide regio-isomers. This methodology was successfully applied to characterizing peptide systems having two disulfide bonds and three disulfide linkage isomers: side-by-side, overlapped, and looped-within-a-loop configurations. [Figure not available: see fulltext.

  10. An UPLC-MS/MS method for separation and accurate quantification of tamoxifen and its metabolites isomers. (United States)

    Arellano, Cécile; Allal, Ben; Goubaa, Anwar; Roché, Henri; Chatelut, Etienne


    A selective and accurate analytical method is needed to quantify tamoxifen and its phase I metabolites in a prospective clinical protocol, for evaluation of pharmacokinetic parameters of tamoxifen and its metabolites in adjuvant treatment of breast cancer. The selectivity of the analytical method is a fundamental criteria to allow the quantification of the main active metabolites (Z)-isomers from (Z)'-isomers. An UPLC-MS/MS method was developed and validated for the quantification of (Z)-tamoxifen, (Z)-endoxifen, (E)-endoxifen, Z'-endoxifen, (Z)'-endoxifen, (Z)-4-hydroxytamoxifen, (Z)-4'-hydroxytamoxifen, N-desmethyl tamoxifen, and tamoxifen-N-oxide. The validation range was set between 0.5ng/mL and 125ng/mL for 4-hydroxytamoxifen and endoxifen isomers, and between 12.5ng/mL and 300ng/mL for tamoxifen, tamoxifen N-desmethyl and tamoxifen-N-oxide. The application to patient plasma samples was performed. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Orbital-like motion of hydride ligands around low-coordinate metal centers. (United States)

    Ortuño, Manuel A; Vidossich, Pietro; Conejero, Salvador; Lledós, Agustí


    Hydrogen atoms in the coordination sphere of a transition metal are highly mobile ligands. Here, a new type of dynamic process involving hydrides has been characterized by computational means. This dynamic event consists of an orbital-like motion of hydride ligands around low-coordinate metal centers containing N-heterocyclic carbenes. The hydride movement around the carbene-metal-carbene axis is the lowest energy mode connecting energy equivalent isomers. This understanding provides crucial information for the interpretation of NMR spectra.

  12. Identification of isomers and control of ionization and dissociation processes using dual-mass-spectrometer scheme and genetic algorithm optimization

    Institute of Scientific and Technical Information of China (English)

    陈洲; 佟秋男; 张丛丛; 胡湛


    Identification of acetone and its two isomers, and the control of their ionization and dissociation processes are per-formed using a dual-mass-spectrometer scheme. The scheme employs two sets of time of flight mass spectrometers to simultaneously acquire the mass spectra of two different molecules under the irradiation of identically shaped femtosecond laser pulses. The optimal laser pulses are found using closed-loop learning method based on a genetic algorithm. Com-pared with the mass spectra of the two isomers that are obtained with the transform limited pulse, those obtained under the irradiation of the optimal laser pulse show large differences and the various reaction pathways of the two molecules are selectively controlled. The experimental results demonstrate that the scheme is quite effective and useful in studies of two molecules having common mass peaks, which makes a traditional single mass spectrometer unfeasible.

  13. Cyclic Versus Linear Isomers Produced by Reaction of the Methylidyne Radical (CH) with Small Unsaturated Hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Goulay, Fabien; Trevitt, Adam J.; Meloni, Giovanni; Selby, Talitha M.; Osborn, David L.; Taatjes, Craig A.; Vereecken, Luc; Leone, Stephen R.


    The reactions of the methylidyne radical (CH) with ethylene, acetylene, allene, and methylacetylene are studied at room temperature using tunable vacuum ultraviolet (VUV) photoionization and time-resolved mass spectrometry. The CH radicals are prepared by 248 nm multiphoton photolysis of CHBr3 at 298 K and react with the selected hydrocarbon in a helium gas flow. Analysis of photoionization efficiency versus VUV photon wavelength permits isomer-specific detection of the reaction products and allows estimation of the reaction product branching ratios. The reactions proceed by either CH insertion or addition followed by H atom elimination from the intermediate adduct. In the CH + C2H4 reaction the C3H5 intermediate decays by H atom loss to yield 70(+-8)percent allene, 30(+-8)percent methylacetylene and less than 10percent cyclopropene, in agreement with previous RRKM results. In the CH + acetylene reaction, detection of mainly the cyclic C3H2 isomer is contrary to a previous RRKM calculation that predicted linear triplet propargylene to be 90percent of the total H-atom co-products. High-level CBS-APNO quantum calculations and RRKM calculation for the CH + C2H2 reaction presented in this manuscript predict a higher contribution of the cyclic C3H2 (27.0percent) versus triplet propargylene (63.5percent) than these earlier predictions. Extensive calculations on the C3H3 and C3H2D system combined with experimental isotope ratios for the CD + C2H2 reaction indicate that H-atom assisted isomerization in the present experiments is responsible for the discrepancy between the RRKM calculations and the experimental results. Cyclic isomers are also found to represent 30(+-6)percent of the detected products in the case of CH + methylacetylene, together with 33(+-6)percent 1,2,3-butatriene and 37(+-6)percent vinylacetylene. The CH + allene reaction gives 23(+-5)percent 1,2,3-butatriene and 77(+-5)percent vinylacetylene, whereas cyclic isomers are produced below the detection limit

  14. 智能配电系统多层级选择性保护技术%The Technology for Selective Coordination of Multilevel Protection in Intelligent Power Distribution System

    Institute of Scientific and Technical Information of China (English)

    张丽萍; 蔡传庆; 缪希仁


    Smart grid is the future development direction of the electric industry. The reliability and continuity of the power supply is particularly concerned by people. Multilevel protection in intelligent power distribution is critical. The conventional method for short circuit fault in low-voltage system is over-current protection. But it has disadvantages such as inadequate of speed and reliability and inadequate of the ability to coordinate at each level etc. In order to research the mechanism of the full range of selective coordination of multi-level protection and improve the existing lack of selective protection, based on the review of applied research of selective protection methods of short-circuit fault in recent years, the paper proposed the experimental system and control and test device technology solution of multi-level selective short-circuit fault protection, and provide an experimental basis for research of low-voltage multi-level selective coordination protection.%智能电网是整个电力行业未来的发展方向,作为其中的重要组成部分,保障智能配电系统供电的可靠性与持续性尤其受人关注。本文从建设坚强智能配电网的需求出发,总结了传统过电流保护技术的不足和包括应用在线监测以及对控制与保护等方面的技术要求,提出低压配电系统多层级选择性保护技术,并分析了多层级选择性保护系统的关键技术实现,展望该技术的应用趋势,为实现多层级全范围选择性保护提供一个新思路。

  15. On the decrease in charge radii of multi-quasi particle isomers

    Energy Technology Data Exchange (ETDEWEB)

    Bissell, M.L. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Flanagan, K.T. [Schuster Laboratory, University of Manchester, Manchester M13 9PL (United Kingdom); Gardner, M.D. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Avgoulea, M. [Schuster Laboratory, University of Manchester, Manchester M13 9PL (United Kingdom); Billowes, J. [Schuster Laboratory, University of Manchester, Manchester M13 9PL (United Kingdom); Campbell, P. [Schuster Laboratory, University of Manchester, Manchester M13 9PL (United Kingdom); Cheal, B. [Schuster Laboratory, University of Manchester, Manchester M13 9PL (United Kingdom)]. E-mail:; Eronen, T. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) FIN-40351 Jyvaeskylae (Finland); Forest, D.H. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Huikari, J. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) FIN-40351 Jyvaeskylae (Finland); Jokinen, A. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) FIN-40351 Jyvaeskylae (Finland); Moore, I.D. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) FIN-40351 Jyvaeskylae (Finland); Nieminen, A. [Schuster Laboratory, University of Manchester, Manchester M13 9PL (United Kingdom); Penttilae, H. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) FIN-40351 Jyvaeskylae (Finland); Rinta-Antila, S. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) FIN-40351 Jyvaeskylae (Finland); Tordoff, B. [Schuster Laboratory, University of Manchester, Manchester M13 9PL (United Kingdom); Tungate, G. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Aystoe, J. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) FIN-40351 Jyvaeskylae (Finland)


    We report changes in mean-square charge radii, {delta}, magnetic moments and quadrupole moments for three multi-quasi particle isomers; {sup 97m2}Y, {sup 176m}Yb and {sup 178m1}Hf. All the isomers are observed to display a decrease in compared to the lower-lying nuclear state on which the isomer is built. The decreases in occur despite the isomers showing increases in quadrupole moment. Possible mechanisms for the effect, which is now seen for six multi-quasi particle isomers, are discussed.

  16. Population and decay of a Kπ=8- two-quasineutron isomer in 244Pu (United States)

    Hota, S. S.; Tandel, S. K.; Chowdhury, P.; Ahmad, I.; Carpenter, M. P.; Chiara, C. J.; Greene, J. P.; Hoffman, C. R.; Jackson, E. G.; Janssens, R. V. F.; Kay, B. P.; Khoo, T. L.; Kondev, F. G.; Lakshmi, S.; Lalkovski, S.; Lauritsen, T.; Lister, C. J.; McCutchan, E. A.; Moran, K.; Peterson, D.; Shirwadkar, U.; Seweryniak, D.; Stefanescu, I.; Toh, Y.; Zhu, S.


    The decay of a Kπ=8- isomer in 244Pu and the collective band structures populating the isomer were studied using deep inelastic excitations with 47Ti and 208Pb beams, respectively. Precise measurements of M 1 /E 2 branching ratios in the band confirm a 9 /2-[734] ν⊗7 /2+[624] ν configuration assignment for the isomer, validating the systematics of Kπ=8- , two-quasineutron isomers observed in even-Z , N =150 isotones. These isomers around the deformed shell gap at N =152 provide critical benchmarks for theoretical predictions of single-particle energies in this gateway region to superheavy nuclei.

  17. Motor coordination: a local hub for coordination. (United States)

    Calabrese, Ronald L


    A local interneuron of a crayfish central pattern generator serves as a hub that integrates ascending and descending coordinating information and passes it on to a local oscillatory microcircuit to coordinate a series of segmental appendages known as swimmerets.

  18. A thirty second isomer in {sup 171}Hf

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, P.; Billowes, J.; Cooper, T.G.; Grant, I.S.; Pearson, M.R.; Wheeler, P.D. [Schuster Laboratory, University of Manchester, M13 9PL (United Kingdom); Cochrane, E.C.A.; Cooke, J.L.; Evans, D.E.; Griffith, J.A.R.; Persson, J.R.; Richardson, D.S.; Tungate, G.; Zybert, L. [School of Physics and Space Research, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Dendooven, P.; Honkanen, A.; Huhta, M.; Oinonen, M.; Penttilae, H.; Aeystoe, J. [Accelerator Laboratory, University of Jyvaeskylae, PL 35 Jyvaeskylae SF-403 51 (Finland)


    An isomer has been detected in {sup 171}Hf with a half-life of T{sub 1/2} 29.5(9) s. The state was populated in the {sup 170}Yb({alpha},3n){sup 171m}Hf reaction at a beam energy of E{sub {alpha}} = 50 MeV in an on-line ion guide isotope separator. The isomeric {sup 171m}Hf{sup +} beam was extracted from the ion guide, mass-analysed and implanted in the surface of a microchannel-plate. The half-life of the collected activity was measured from the decay of the microchannel-plate count rate. We associate the isomer with the first excited state in {sup 171}Hf with spin 1/2{sup -} at an excitation energy of 22(2) keV. (author)

  19. Fluorescence characteristics of polychlorinated biphenyl isomers in cyclodextrin media

    Energy Technology Data Exchange (ETDEWEB)

    Femia, R.A.; Scypinski, S.; Love, L.J.C.


    The fluorescence characteristics of several polychlorinated biphenyl (PCB) isomers in ..cap alpha..- and ..beta..-cyclodextrin (CD) are discussed and contrasted. The steric hindrance of PCBs imposed by the positions of the chlorine atoms on the rings determines the overall stability of the resulting inclusion complexes with cyclodextrin which is reflected in the fluorescence intensities. Less substituted homologues include into the CD cavity equally well in both cyclodextrins, but very heavily substituted molecules show drastic differences between their fluorescence intensities in the ..cap alpha..- and ..beta..-cyclodextrin solutions. This behavior can be employed as a method for spectral fractionation of PCB isomers. Spectral separation is demonstrated here for two variably substituted molecules, and the photophysical limitations of this approach are discussed.

  20. Spectroscopic Studies of the Several Isomers of UO3

    Energy Technology Data Exchange (ETDEWEB)

    Sweet, Lucas E.; Reilly, Dallas D.; Abrecht, David G.; Buck, Edgar C.; Meier, David E.; Su, Yin-Fong; Brauer, Carolyn S.; Schwantes, Jon M.; Tonkyn, Russell G.; Szecsody, James E.; Blake, Thomas A.; Johnson, Timothy J.


    Uranium trioxide is known to adopt seven different structural forms. While these structural forms have been well characterized using x-ray or neutron diffraction techniques, little work has been done to characterize their spectroscopic properties, particularly of the pure phases. Since the structural isomers of UO3 all have similar thermodynamic stabilities and most tend to hydrolyze under open atmospheric conditions, mixtures of UO3 phases and the hydrolysis products are common. Much effort went into isolating pure phases of UO3. Utilizing x-ray diffraction as a sample identification check, UV/Vis/NIR spectroscopic signatures of α-UO3, β-UO3, γ-UO3 and UO2(OH)2 products were obtained. The spectra of the pure phases can now be used to characterize typical samples of UO3, which are often mixtures of isomers.

  1. Observation of the 2$^+$ isomer in $^{52}$Co

    CERN Document Server

    Orrigo, S E A; Gelletly, W; Fujita, Y; Blank, B; Giovinazzo, J; Agramunt, J; Algora, A; Ascher, P; Bilgier, B; Cáceres, L; Cakirli, R B; de France, G; Ganioğlu, E; Gerbaux, M; Grévy, S; Kamalou, O; Kozer, H C; Kucuk, L; Kurtukian-Nieto, T; Molina, F; Popescu, L; Rogers, A M; Susoy, G; Stodel, C; Suzuki, T; Tamii, A; Thomas, J C


    We report the first observation of the 2$^+$ isomer in $^{52}$Co, produced in the $\\beta$ decay of the 0$^+$, $^{52}$Ni ground state. We have observed three $\\gamma$-rays at 849, 1910, and 5185 keV characterizing the de-excitation of the isomer. We have measured a half-life of 102(6) ms for the isomeric state. The Fermi and Gamow-Teller transition strengths for the $\\beta$ decay of $^{52m}$Co to $^{52}$Fe have been determined. We also add new information on the $\\beta$ decay of the 6$^+$, $^{52}$Co ground state, for which we have measured a half-life of 112(3) ms.

  2. The structural and dynamical variables of pentane isomers (United States)

    Patel, Tarika K.; Vaghela, M. V.; Gajjar, P. N.


    We derived structural and dynamical properties of pentane isomers: normal pentane, iso-pentane and neo pentane for liquid and gaseous state. We use molecular dynamics simulation to calculate the dynamical properties of pentane isomers for number of particles 729 using the intermolecular potential and force due to Lenard Jones potential. The computations also include mean square displacement and self diffusion co-efficient using Einstein relation. In structural properties, structure factor and phonon frequency are obtaining from P Y Method and Hubbard and Beeby Approach respectively. The Intermolecular potential and self diffusion co-efficient depend on the branching in the structure. The pair correlation function and phonon dispersion curves revels the complex structure of neo-pentane with respect to iso-pentane and n-pentane.

  3. Theoretical characterisation of the SSO, cyclic SOS and SOS isomers (United States)

    Denis, Pablo A.


    The SSO, cyclic SOS and open SOS isomers have been investigated, employing the CCSD(T) methodology and the cc-pV(X + d)Z X = 3, 4, 5, 6 basis sets. The anharmonic force fields have been calculated to predict the fundamental vibrational frequencies, rotational constants, vibration-rotation corrections, anharmonic corrections to zero-point energies, and structural parameters. At the CCSD(T)/CBS limit and including corrections for scalar relativistic effects, complete quadruple excitations, spin-orbit and core-valence correlation effects, the estimated enthalpies of formation are -13.9 ± 1, 32.1 ± 1, and -51.2 ± 1 kcal/mol, for SSO, cyclic-SOS and open-SOS, respectively. Finally, it was found that the asymmetric SO stretch of the open and cyclic SOS isomers are located in a nearly identical position and it is likely that SOS also maybe present in the surface of Io.

  4. Mobilities of Li(+)-attached butanol isomers in He gas. (United States)

    Takahashi, K; Saito, K; Koizumi, T; Matoba, S; Kojima, T M; Tanuma, H; Shiromaru, H


    Mobilities of Li(+)-attached butanol isomers, (n-BuOH)Li(+), (s-BuOH)Li(+), (i-BuOH)Li(+), and (t-BuOH)Li(+), in helium gas were measured over a range of reduced electric fields (E/N = 25-96 Td) at room temperature. Arrival time measurements accurately identified small differences in the measured mobilities of the isomer ions. At low E/N (≤30 Td, corresponding to a mean collision energy ε≤0.05 eV), (n-BuOH)Li(+) showed a mobility about 1.5% greater than that of the other ions, but at high E/N (≥75 Td, ε≥0.1 eV) its mobility was about 1.1% less.

  5. Preparation of Conjugated Linoleic Acid and Identification of Its Isomers

    Institute of Scientific and Technical Information of China (English)

    郭诤; 张根旺; 孙彦


    Conjugated linoleic acid(CLA)is a kind of fatty acid with physiological activities and potential appli-cation prospect ,A synthesis method of conjugated linoleic acid and a purification technology were studied .CLA was prepared and purified by urea-complexation and conjugation using safflower oil as raw material,The purity of CLA and total recovery of the product was more than 95% and 48%,respectively,The main isomers produced in alkali-catalyzed conjugation were identified by gas chromatography (GC)linked to mass spectrometry(MS) and Fourier transform infrared spectroscopy(FTIR),The total amount of the two main isomers (9cis,11trans-and 10trans,12cis-CLA) determined by GC was more than 90% of the product.

  6. A simple, rapid method for HPLC analysis of lycopene isomers. (United States)

    Ishida, B K; Ma, J; Chan, B


    A rapid method for the extraction, separation and quantification of the geometric isomers of lycopene and beta-carotene from tomato fruit is described. Carotenoids in tomato were separated and eluted using a reversed-phase HPLC with a C30 column and a mobile phase consisting of methyl-t-butyl ether, methanol and ethyl acetate. The system provided sharp resolution of cis- and trans-isomers of lycopene within approximately 23 min in contrast to the longer and more complex gradient procedures required by previously described methods. Experiments indicate that the stability of extracts of fresh tomato may be improved if stored at -20 degrees C, and that the presence of the antioxidant BHA has no apparent effect on stability.

  7. Lubricating and Waxy Esters. VI. Effect of Symmetry about Ester on Crystallization of Linear Monoester Isomers

    Directory of Open Access Journals (Sweden)

    Laziz Bouzidi


    Full Text Available The crystal structure development of jojoba-like esters incorporating either 1-decenoic acid and/or 1-decenol, namely octadec-9-enyl dec-9-enoate (JLE-281, and its isomer dec-9-enyl oleate (JLE-282 was investigated to reveal the effect of symmetry about the ester group on crystallization of aliphatic fatty monoesters. The phase transformation path was investigated with temperature-time resolved X-ray diffraction during stepped isothermal crystallization, and while cooling from the melt at a fixed rate. Startling differences in phase behavior were uncovered between the isomers. When stepped isothermals were used, selective extinctions occurred at a transition temperature for JLE-281 but not for JLE-282. The extinctions, which are due to dramatic changes in the electronic density of certain families of planes, indicate a phase transition attributed to a brusque rearrangement of the oxygen atoms in the crystal subcell. The phase transition did not occur when the JLEs were cooled continuously. The crucial role played by the position of the alkyl chain and its orientation relative to the easy rotation site of the C–O bond in the phase trajectories of the JLEs was particularly highlighted.

  8. Observation of new microsecond isomers among fission products of 345 MeV/nucleon 238U

    CERN Document Server

    Kameda, D; Ohnishi, T; Kusaka, K; Yoshida, A; Yoshida, K; Ohtake, M; Fukuda, N; Takeda, H; Tanaka, K; Inabe, N; Yanagisawa, Y; Gono, Y; Watanabe, H; Otsu, H; Baba, H; Ichihara, T; Yamaguchi, Y; Takechi, M; Nishimura, S; Ueno, H; Yoshimi, A; Sakurai, H; Motobayashi, T; Nakao, T; Mizoi, Y; Matsushita, M; Ieki, K; Kobayashi, N; Tanaka, K; Kawada, Y; Tanaka, N; Deguchi, S; Satou, Y; Kondo, Y; Nakamura, T; Yoshinaga, K; Ishii, C; Yoshii, H; Miyashita, Y; Uematsu, N; Shiraki, Y; Sumikama, T; Chiba, J; Ideguchi, E; Saito, A; Yamaguchi, T; Hachiuma, I; Suzuki, T; Moriguchi, T; Ozawa, A; Ohtsubo, T; Famiano, M A; Geissel, H; Nettleton, A S; Tarasov, O B; Bazin, D; Sherrill, B M; Manikonda, S L; Nolen, J A


    A search for isomeric gamma-decays among fission fragments from 345 MeV/nucleon 238U has been performed at the RIKEN Nishina Center RI Beam Factory. Fission fragments were selected and identified using the superconducting in-flight separator BigRIPS and were implanted in an aluminum stopper. Delayed gamma-rays were detected using three clover-type high-purity germanium detectors located at the focal plane within a time window of 20 microseconds following the implantation. We identified a total of 54 microsecond isomers with half-lives of ~0.1 - 10 microseconds, including discovery of 18 new isomers in very neutron-rich nuclei: 59Tim, 90Asm, 92Sem, 93Sem, 94Brm, 95Brm, 96Brm, 97Rbm, 108Nbm, 109Mom, 117Rum, 119Rum, 120Rhm, 122Rhm, 121Pdm, 124Pdm, 124Agm and 126Agm, and obtained a wealth of spectroscopic information such as half-lives, gamma-ray energies, gamma-ray relative intensities and gamma-gamma coincidences over a wide range of neutron-rich exotic nuclei. Proposed level schemes are presented for 59Tim, 82...

  9. Separation of positional CPP isomers by chiral HPLC-DAD of seized tablets. (United States)

    Schürenkamp, Jennifer; Beike, Justus; Pfeiffer, Heidi; Köhler, Helga


    Meta-chlorophenylpiperazine, one of the synthetic piperazine-derived designer drugs, is to date controlled as an illicit substance in five European member states. Depending on the position of the chlorine atom, different positional isomers of CPP (ortho-, meta- and para-) are possible. Therefore, there is a need to develop an analytical method for the separation and identification of the three 1-chlorophenylpiperazines in tablets containing CPP. In this work, the position isomers o-, m- and p-CPP were separated by liquid chromatography (HPLC) on a reversed-phase chiral column. Different mobile phase compositions and pH ranges were systematically studied to find optimum chromatographic conditions. Best results were achieved with isocratic mobile phase of triethyl amine buffer and methanol (V/V = 70/30) at pH 9 with a flow rate of 0.8 ml/min. The method was validated in terms of selectivity, linearity, limit of detection and quantification and precision. At last, the developed method was successfully applied on seized ecstasy tablets.

  10. Condensations of single DNA molecules induced by heptaplatin and its chiral isomer (United States)

    Zhang, Hong-Yan; Liu, Yu-Ru; Li, Wei; Li, Hui; Dou, Shuo-Xing; Xie, Ping; Wang, Wei-Chi; Wang, Peng-Ye


    Heptaplatin is a third-generation platinum antitumor drug. It has a chiral isomer. We studied the interactions between the two isomers and DNA by using magnetic tweezers and atomic force microscopy (AFM) to investigate the effect of chiralities of the isomers on the interactions. We found that the extension curves and average condensation rates of DNA molecules incubated with heptaplatin were nearly the same as those incubated with its chiral isomer. In addition, the structures of DNA molecules incubated with heptaplatin were also similar to those incubated with its chiral isomer. These results indicate the difference in chirality of the two isomers does not induce different interactions of the isomers with DNA. Our study may facilitate the understanding of interactions of platinum complexes with DNA and the design of new antitumor platinum complexes.

  11. Focal point analysis of torsional isomers of acrylic acid (United States)

    Alev Çiftçioğlu, Gökçen; Trindle, Carl; Yavuz, Ilhan


    The thermochemistry of acrylic acid has presented challenges owing to its high reactivity, tendency to dimerize in the gas phase, and the existence of two very nearly equal energy conformational isomers. Well-tested thermochemical schemes including G2, G3, G4, and CBS-QB3 agree in the prediction that the s-cis syn structure is the most stable of the torsional isomers, with the s-cis anti form lying 3 kJ mol-1 or less higher in energy. Microwave spectra suggest a value of 0.63 kJ mol-1. The energy barrier between these forms is in the neighbourhood of 25 kJ mol-1 according to a MP2/cc-pVDZ calculation. We present estimates of the relative energies of all four torsional isomers and the rotational barrier based on a variant of the Focal Point Analysis developed by Császár and co-workers. These calculations, extending to the CCSD(T)/cc-pV5Z level, predict that the s-cis anti torsional isomer is the most stable form, in contrast to prior estimates. The s-cis syn form lies about 2.9 kJ mol-1 higher, while the s-trans syn and anti forms lie at about 21.7 and 23.3 kJ mol-1, respectively. We estimate the rotational barrier between the s-cis trans and s-cis anti structures to be about 23.9 kJ mol-1. Error ranges derived from the fit to extrapolation forms suggest that our estimates have an uncertainty of about 0.1 kJ mol-1.

  12. Island of high-spin isomers near N = 82

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, J.; Back, B.B.; Bernthal, F.M.; Bjornholm, S.; Borggreen, J.; Christensen, O.; Folkmann, F.; Herskind, B.; Khoo, T.L.; Neiman, M.; Puehlhofer, F.; Sletten, G.


    Experiments aimed at testing for the existence of yrast traps are reported. A search for delayed ..gamma.. radiation of lifetimes longer than approx. 10 ns and of high multiplicity has been performed by producing more than 100 compound nuclei between Ba and Pb in bombardments with /sup 40/Ar, /sup 50/Ti, and /sup 65/Cu projectiles. An island of high-spin isomers is found to exist in the region 64 < or approx. = Z > or approx. = 71 and N < or approx. = 82.

  13. Characteristics of Butanol Isomers Oxidation in a Micro Flow Reactor

    KAUST Repository

    Bin Hamzah, Muhamad Firdaus


    Ignition and combustion characteristics of n-butanol/air, 2-butanol.air and isobutanol/air mixtures at stoichiometric (ϕ = 1) and lean (ϕ = 0.5) conditions were investigated in a micro flow reactor with a controlled temperature profile from 323 K to 1313 K, under atmospheric pressure. Sole distinctive weak flame was observed for each mixture, with inlet fuel/air mixture velocity set low at 2 cm/s. One-dimensional computation with comprehensive chemistry and transport was conducted. At low mixture velocities, one-stage oxidation was confirmed from heat release rate profiles, which was broadly in agreement with the experimental results. The weak flame positions were congruent with literature describing reactivity of the butanol isomers. These weak flame responses were also found to mirror the trend in Anti-Knock Indexes of the butanol isomers. Flux and sensitivity analyses were performed to investigate the fuel oxidation pathways at low and high temperatures. Further computational investigations on oxidation of butanol isomers at higher pressure of 5 atm indicated two-stage oxidation through the heat release rate profiles. Low temperature chemistry is accentuated in the region near the first weak cool flame for oxidation under higher pressure, and its impact on key species – such as hydroxyl radical, hydrogen peroxide and carbon monoxide – were considered. Both experimental and computational findings demonstrate the advantage of employing the micro flow reactor in investigating oxidation processes in the temperature region of interest along the reactor channel. By varying physical conditions such as pressure, the micro flow reactor system is proven to be highly beneficial in elucidating oxidation behavior of butanol isomers in conditions in engines such as those that mirror HCCI operations.

  14. Determination of aminocresol isomers by high-speed liquid chromatography. (United States)

    Sakurai, H; Kito, M

    Aminocresol isomers (4-hydroxy-m-toluidine [II], 3-hydroxy-p-toluidine [II], 2-hydroxy-p-toluidine [III]) and p-aminophenol have been separated and determined by a high-speed liquid Chromatographie method. Since this method is applicable in aqueous media, it was used to investigate the suitability of a haemin-cysteine system as a model for the cytochrome P-450 mono-oxygenase system, by determination of the [I], [II], [III] and p-aminophenol formed.

  15. Flame Propagation of Butanol Isomers/Air Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Veloo, Peter S.; Egolfopoulos, Fokion N.


    An experimental and computational study was conducted on the propagation of flames of saturated butanol isomers. The experiments were performed in the counterflow configuration under atmospheric pressure, unburned mixture temperature of 343 K, and for a wide range of equivalence ratios. The experiments were simulated using a recent kinetic model for the four isomers of butanol. Results indicate that n-butanol/air flames propagate somewhat faster than both sec-butanol/air and iso-butanol/air flames, and that tert-butanol/air flames propagate notably slower compared to the other three isomers. Reaction path analysis of tert-butanol/air flames revealed that iso-butene is a major intermediate, which subsequently reacts to form the resonantly stable iso-butenyl radical retarding thus the overall reactivity of tert-butanol/air flames relatively to the other three isomers. Through sensitivity analysis, it was determined that the mass burning rates of sec-butanol/air and iso-butanol/air flames are sensitive largely to hydrogen, carbon monoxide, and C{sub 1}–C{sub 2} hydrocarbon kinetics and not to fuel-specific reactions similarly to n-butanol/air flames. However, for tert-butanol/air flames notable sensitivity to fuel-specific reactions exists. While the numerical results predicted closely the experimental data for n-butanol/air and sec-butanol/air flames, they overpredicted and underpredicted the laminar flame speeds for iso-butanol/air and tert-butanol/air flames respectively. It was demonstrated further that the underprediction of the laminar flame speeds of tert-butanol/air flames by the model was most likely due to deficiencies of the C{sub 4}-alkene kinetics.

  16. Spectroscopic and computational study of a new isomer of salinomycin (United States)

    Pankiewicz, Radosław


    A new derivative of polyether ionophore salinomycin was obtained as a result of a rearrangement catalysed by sulphuric acid in two-phase medium of water/methylene chloride solution. The new isomer was fully characterized by multinuclear 2D NMR, NOESY and MALDI-TOF. The properties of the new compound were additionally study by semiempirical (PM5) and DFT (B3LYP) methods. A potential mechanism of the rearrangement was also proposed.

  17. Characterization and performance of short cationic antimicrobial peptide isomers. (United States)

    Juba, Melanie; Porter, Devin; Dean, Scott; Gillmor, Susan; Bishop, Barney


    Cationic antimicrobial peptides (CAMPs) represent an ancient defense mechanism against invading bacteria, with peptides such as the cathelicidins being essential elements of vertebrate innate immunity. CAMPs are typically associated with broad-spectrum antimicrobial potency and limited bacterial resistance. The cathelicidin identified from the elapid snake Naja atra (NA-CATH) contains a semi-conserved repeated 11-residue motif (ATRA motif) with a sequence pattern consistent with formation of an amphipathic helical conformation. Short peptide amides (ATRA-1, -1A, -1P, and -2) generated based on the pair of ATRA motifs in NA-CATH exhibited varied antimicrobial potencies. The small size of the ATRA peptides, coupled with their varied antimicrobial performances, make them interesting models to study the impact various physico-chemical properties have on antimicrobial performance in helical CAMPs. Accordingly, the D- and L-enantiomers of the peptide ATRA-1A, which in earlier studies had shown both good antimicrobial performance and strong helical character, were investigated in order to assess the impact peptide stereochemistry has on antimicrobial performance and interaction with chiral membranes. The ATRA-1A isomers exhibit varied potencies against four bacterial strains, and their conformational properties in the presence of mixed zwitterionic/anionic liposomes are influenced by anionic lipid content. These studies reveal subtle differences in the properties of the peptide isomers. Differences are also seen in the abilities of the ATRA-1A isomers to induce liposome fusion/aggregation, bilayer rearrangement and lysing through turbidity studies and fluorescence microscopy. The similarities and differences in the properties of the ATRA-1A isomers could aid in efforts to develop D-peptide-based therapeutics using high-performing L-peptides as templates.

  18. Harmonic Vibrational Analysis in Delocalized Internal Coordinates. (United States)

    Jensen, Frank; Palmer, David S


    It is shown that a principal component analysis of a large set of internal coordinates can be used to define a nonredundant set of delocalized internal coordinates suitable for the calculation of harmonic vibrational normal modes. The selection of internal coordinates and the principal component analysis provide large degrees of freedom in extracting a nonredundant set of coordinates, and thus influence how the vibrational normal modes are described. It is shown that long-range coordinates may be especially suitable for describing low-frequency global deformation modes in proteins.

  19. Isomer probes of nuclear structure following deep inelastic collisions

    CERN Document Server

    Al-Garni, S A; Walker, P


    Deep-inelastic collisions of sup 1 sup 3 sup 6 Xe ions with tantalum, tungsten and rhenium targets have been used to study beta-decays and high-spin isomers in neutron-rich A approx 180 nuclei at the GSI on-line mass separator. In particular, gamma rays -associated with the decay of the previously identified K suppi = 37/2 sup - , T sub 1 sub / sub 2 = 51 min isomer in sup 1 sup 7 sup 7 Hf have been observed, but with an unexpectedly high yield considering the release efficiency for short-lived hafnium isotopes from a thermal ion source. These results may be interpreted as possible evidence for a hitherto unrecognised, high-spin beta-decaying isomer in sup 1 sup 7 sup 7 Lu. A two-component half-life analysis of the sup 1 sup 7 sup 7 Hf gamma-ray intensities gives an upper-lying component of 6 + 3 - 2 min, when the lower-lying component half-life is fixed at 51 min. Nilsson multi-quasiparticle calculations with BCS pairing predict a favoured K suppi = 39/2 sup - state in sup 1 sup 7 sup 7 Lu, which is a candid...

  20. Isomer-specific biodegradation of methylphenanthrenes by soil bacteria. (United States)

    Lamberts, Rasmus F; Christensen, Jan H; Mayer, Philipp; Andersen, Ole; Johnsen, Anders R


    It is assumed that bacteria generally degrade 2-methylphenanthrene (2MPhe) in preference to 1-methylphenanthrene (1MPhe), and that environmental biodegradation of methylated PAHs therefore can be described qualitatively by changes in relative concentrations of these isomers. Our objective was to investigate whether microbial phenanthrene degraders (Sphingomonas and Mycobacterium) show such isomer-specific PAH degradation. Eleven out of twenty-nine phenanthrene degraders could grow on methylphenanthrene. The mycobacteria grew only on 2MPhe, the sphingomonads grew mostly on 1MPhe, and one sphingomonad could utilize both substrates. Seven strains were tested in a two-phase system where 1MPhe and 2MPhe were supplied in heptamethylnonane. For these strains, a consistent description of biodegradation based on the 2MPhe/1MPhe diagnostic ratio would not be possible because three Mycobacterium and one Sphingomonas degraded 2MPhe faster than 1MPhe, another Sphingomonas degraded 1MPhe and 2MPhe at almost equal rates, and two Sphingomonas degraded 1MPhe faster than 2MPhe. Thus, environmental biodegradation of phenanthrenes may theoretically proceed with only minor changes in 2MPhe/1MPhe ratios if individual members of the degrader community have different isomer preferences. However, two soil microcosms polluted with bunker oil confirmed the general decline in 2MPhe/1MPhe ratio during oil biodegradation.

  1. Diffusion studies of dihydroxybenzene isomers in water-alcohol systems. (United States)

    Codling, Dale J; Zheng, Gang; Stait-Gardner, Tim; Yang, Shu; Nilsson, Mathias; Price, William S


    Nuclear magnetic resonance diffusion studies can be used to identify different compounds in a mixture. However, because the diffusion coefficient is primarily dependent on the effective hydrodynamic radius, it is particularly difficult to resolve compounds with similar size and structure, such as isomers, on the basis of diffusion. Differential solution interactions between species in certain solutions can afford possibilities for separation. In the present study, the self-diffusion of the three isomers of dihydroxybenzene (i.e., (1,2-) catechol, (1,3-) resorcinol, and (1,4-) hydroquinone) was studied in water, aqueous monohydric alcohols (i.e., ethanol, 1-propanol, tert-butanol), and aqueous ethylene glycol. These systems allowed the effects of isomerism and differential solvent interactions on diffusion to be examined. It was found that, while in aqueous solution these isomers had the same diffusion coefficient, in water-monohydric alcohol systems the diffusion coefficient of catechol differed from those of resorcinol and hydroquinone. The separation was found to increase at higher concentrations of monohydric alcohols. The underlying chemical reasons for these differences were investigated.

  2. Borromean halo, Tango halo, and halo isomers in atomic nuclei (United States)

    Izosimov, Igor


    Structure of the ground and excited states in halo-like nuclei is discussed. Both the Borromean and tango halo types can be observed for n-p configurations of atomic nuclei.Structure of the halo may be different for the different levels and resonances in atomic nuclei. Isobar analog, double isobar analog, configuration, and double configuration states can simultaneously have n-n, n-p, and p-p halo components in their wave functions. When the halo structure of the excited state differs from that of the ground state, or the ground state has non-halo structure, the γ-transition from the excited state to the ground state can be essentially hindered, i.e. the formation of a specific type of isomers (halo isomers) becomes possible. B(Mγ) and B(Eγ) values for γ-transitions in 6,7,8Li, 8,9,10Be, 8,10,11B, 10,11,12,13,14C, 13,14,15,16,17N, 15,16,17,19O, and 17F are analyzed. Special attention is given to nuclei which ground state does not exhibit halo structure but the excited state (halo isomer) may have one.

  3. Some properties of emission coordinates

    CERN Document Server

    Pozo, J M


    4 emitters broadcasting an increasing electromagnetic signal generate a system of relativistic coordinates for the space-time, called emission coordinates. Their physical realization requires an apparatus similar to the one of the Global Navigation Satellite Systems (GNSS). Several relativistic corrections are utilized for the current precisions, but the GNSS are conceived as classical (Newtonian) systems, which has deep implications in the way of operating them. The study of emission coordinates is an essential step in order to develop a fully relativistic theory of positioning systems. This talk presents some properties of emission coordinates. In particular, we characterize how any observer sees a configuration of satellites giving a degenerated system and show that the trajectories of the satellites select a unique privileged observer at each point and, for any observer, a set of 3 orthogonal spatial axes.

  4. Highly selective hydrocarboxylation of styrene with oxalic acid or water using palladium ortho-amino arenethiolates with intramolecular co-ordinating nitrogen Lewis bases

    NARCIS (Netherlands)

    Koten, G. van; Kruis, D.; Ruiz, N.; Janssen, M.D.; Boersma, J.; Claver, C.


    Under mild conditions and in the presence of a catalytic amount of an S, N-chelated palladium ortho-amino arenethiolate complex, styrene reacts with carbon monoxide and oxalic acid or water to selectively give 2-phenylpropanoic acid in high yield.

  5. Methanation on mass-selected Ru nanoparticles on a planar SiO2 model support: The importance of under-coordinated sites

    DEFF Research Database (Denmark)

    Masini, Federico; Strebel, Christian Ejersbo; McCarthy, David Norman


    Mass-selected Ru nanoparticles were deposited onto planar SiO2 support and their capability for the methanation reaction investigated. The catalytic activity for the methanation reaction at 100mbar under hydrogen rich conditions (1:99 CO/H2 ratio) was measured as a function of particle size. We f...

  6. Selective Binding of O(2) over N(2) in a Redox-Active Metal-Organic Framework with Open Iron(II) Coordination Sites

    Energy Technology Data Exchange (ETDEWEB)

    Bloch, Eric D; Murray, Leslie J; Queen, Wendy L; Chavan, Sachin; Maximoff, Sergey N; Bigi, Julian P; Krishna, Rajamani; Peterson, Vanessa K; Grandjean, Fernande; Long, Gary J; Smit, Berend; Bordiga, Silvia; Brown, Craig M; Long, Jeffrey R


    The air-free reaction between FeCl₂ and H₄dobdc (dobdc{sup 4–} = 2,5-dioxido-1,4-benzenedicarboxylate) in a mixture of N,N-dimethylformamide (DMF) and methanol affords Fe₂(dobdc)·4DMF, a metal–organic framework adopting the MOF-74 (or CPO-27) structure type. The desolvated form of this material displays a Brunauer–Emmett–Teller (BET) surface area of 1360 m²/g and features a hexagonal array of one-dimensional channels lined with coordinatively unsaturated Fe{sup II} centers. Gas adsorption isotherms at 298 K indicate that Fe₂(dobdc) binds O₂ preferentially over N₂, with an irreversible capacity of 9.3 wt %, corresponding to the adsorption of one O₂ molecule per two iron centers. Remarkably, at 211 K, O₂ uptake is fully reversible and the capacity increases to 18.2 wt %, corresponding to the adsorption of one O₂ molecule per iron center. Mössbauer and infrared spectra are consistent with partial charge transfer from iron(II) to O₂ at low temperature and complete charge transfer to form iron(III) and O₂{sup 2–} at room temperature. The results of Rietveld analyses of powder neutron diffraction data (4 K) confirm this interpretation, revealing O₂ bound to iron in a symmetric side-on mode with d{sub O–O} = 1.25(1) Å at low temperature and in a slipped side-on mode with dO–O = 1.6(1) Å when oxidized at room temperature. Application of ideal adsorbed solution theory in simulating breakthrough curves shows Fe₂(dobdc) to be a promising material for the separation of O₂ from air at temperatures well above those currently employed in industrial settings.

  7. Three luminescent d{sup 10} metal coordination polymers assembled from a semirigid V-shaped ligand with high selective detecting of Cu{sup 2+} ion and nitrobenzene

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wei-Ping [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorg. Chem., College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Institute of Functional Materials, College of Chemistry and Pharmaceutical Engineering, Sichuan University of Science & Engineering, Zigong 643000 (China); Liu, Ping; Liang, Yu-Tong; Cui, Lin; Xi, Zheng-Ping [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorg. Chem., College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Wang, Yao-Yu, E-mail: [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorg. Chem., College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China)


    Three 2D luminescent coordination polymers with helical frameworks, [ZnL{sub 2}]{sub n} (1) and ([ML{sub 2}]·(H{sub 2}O)){sub n} (M=Zn (2), Cd (3)) (HL=4-((2-methyl-1 H-imidazol-1-yl)methyl)benzoic acid), have been assembled under hydro(solvo)thermal conditions. Complex 1 is in chiral space group and displays a rare 2D→2D 2-fold parallel interpenetrated layer network with two types of chiral double helixes. Interestingly, the single crystal structure analyses indicate the coexistence of enantiomers la and 1b in one pot, while the bulk crystallization of 1 are racemic mixtures based on the CD measurement. 2 and 3 are isostructural, in the structure, there are two kinds of 2D chiral helical-layers which stack in an -ABAB- sequence leading to the overall structure are mesomer and achiral. All compounds display intense luminescence in solid state at room temperature with high chemical and thermal stability. More importantly, 1 has been successfully applied in the detection of Cu{sup 2+} ions in aqueous media and nitrobenzene and the probable detecting mechanism was also discussed. - Graphical abstract: Three luminescent d{sup 10} metal coordination polymers with helical-layer based on 4-((2-methyl-1H-imidazol-1-yl)methyl)benzoic acid have been obtained. Compound 1 shows high selective detecting for Cu{sup 2+} ion in aqueous and nitrobenzene. - Highlights: • Three coordination polymers with chiral helical-layer have been obtained. • 1 Can luminescent detect Cu{sup 2+} ion in aqueous media and nitrobenzene. • Racemic mixture or mesomer compounds can be obtained by controlling the reaction conditions.

  8. Isomer separation of $^{70g}Cu$ and $^{70m}Cu$ with a resonance ionization laser ion source

    CERN Document Server

    Köster, U; Mishin, V I; Weissman, L; Huyse, M; Kruglov, K; Müller, W F; Van Duppen, P; Van Roosbroeck, J; Thirolf, P G; Thomas, H C; Weisshaar, D W; Schulze, W; Borcea, R; La Commara, M; Schatz, H; Schmidt, K; Röttger, S; Huber, G; Sebastian, V; Kratz, K L; Catherall, R; Georg, U; Lettry, Jacques; Oinonen, M; Ravn, H L; Simon, H


    Radioactive copper isotopes were ionized with the resonance ionization laser ion source at the on-line isotope separator ISOLDE (CERN). Using the different hyperfine structure in the 3d/sup 10/ 4s /sup 2/S/sub 1/2/-3d/sup 10/ 4p /sup 2/P/sub 1/2//sup 0/ transition the low- and high-spin isomers of /sup 70/Cu were selectively enhanced by tuning the laser wavelength. The light was provided by a narrow-bandwidth dye laser pumped by copper vapor lasers and frequency doubled in a BBO crystal. The ground state to isomeric state intensity ratio could be varied by a factor of 30, allowing to assign gamma transitions unambiguously to the decay of the individual isomers. It is shown that the method can also be used to determine magnetic moments. In a first experiment for the 1/sup +/ ground state of /sup 70/Cu a magnetic moment of (+)1.8(3) mu /sub N/ and for the high-spin isomer of /sup 70/Cu a magnetic moment of (+or-)1.2(3) mu /sub N/ could be deduced. (20 refs).

  9. Distribution of perfluorooctane sulfonate isomers and predicted risk of thyroid hormonal perturbation in drinking water. (United States)

    Yu, Nanyang; Wang, Xiaoxiang; Zhang, Beibei; Yang, Jingping; Li, Meiying; Li, Jun; Shi, Wei; Wei, Si; Yu, Hongxia


    We documented the distribution of seven perfluorooctane sulfonate (PFOS) isomers in drinking water in Jiangsu Province, China. Compared to the 30% proportion of branched PFOS in technical PFOS, the levels of branched PFOS in drinking water increased to 31.8%-44.6% of total PFOS. Because of previous risk assessment without considering the PFOS isomer profile and the toxicity of individual PFOS isomers, here we performed a new health risk assessment of PFOS for thyroid hormonal perturbation in drinking water with the contribution from individual PFOS isomers. The risk quotients (RQs) of individual PFOS isomers indicated that linear PFOS contributed most to the risk among all the target PFOS isomers (83.0%-90.2% of the total PFOS RQ), and that risk from 6m-PFOS (5.2%-11.9% of the total PFOS RQ) was higher than that from other branched PFOS isomers. We found that the risks associated with PFOS in drinking water would be overestimated by 10.0%-91.7% if contributions from individual PFOS isomers were not considered. The results revealed that the PFOS isomer profile and the toxicity of individual PFOS isomers were important factors in health risk assessment of PFOS and should be considered in the future risk assessments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Test purchase, synthesis, and characterization of 2-methoxydiphenidine (MXP) and differentiation from its meta- and para-substituted isomers. (United States)

    McLaughlin, Gavin; Morris, Noreen; Kavanagh, Pierce V; Power, John D; O'Brien, John; Talbot, Brian; Elliott, Simon P; Wallach, Jason; Hoang, Khoa; Morris, Hamilton; Brandt, Simon D


    The structurally diverse nature of the 1,2-diphenylethylamine template provides access to a range of substances for drug discovery work but some have attracted attention as 'research chemicals'. The most recent examples include diphenidine, i.e. 1-(1,2-diphenylethyl)piperidine and 2-methoxydiphenidine, i.e. 1-[1-(2-methoxyphenyl)-2-phenylethyl]piperidine (MXP, methoxyphenidine, 2-MXP) that have been associated with uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist activity. Analytical challenges encountered during chemical analysis include the presence of positional isomers. Three powdered samples suspected to contain 2-MXP were obtained from three Internet retailers in the United Kingdom and subjected to analytical characterization by gas chromatography (GC) and high performance liquid chromatography (HPLC) coupled to various forms of mass spectrometry (MS). Nuclear magnetic resonance spectroscopy, infrared spectroscopy and thin layer chromatography were also employed. This was supported by the synthesis of all three isomers (2-, 3- and 4-MXP) by two different synthetic routes. The analytical data obtained for the three purchased samples were consistent with the synthesized 2-MXP standard and the differentiation between the isomers was possible. Distinct stability differences were observed for all three isomers during in-source collision-induced dissociation of the protonated molecule when employing detection under HPLC selected-ion monitoring detection, which added to the ability to differentiate between them. Furthermore, the analysis of a 2-MXP tablet by matrix assisted inlet ionization Orbitrap mass spectrometry confirmed that it was possible to detect the protonated molecule of 2-MXP directly from the tablet surface following addition of 3-nitrobenzonitrile as the matrix.

  11. Limitations of Radar Coordinates


    Bini, Donato; Lusanna, Luca; Mashhoon, Bahram


    The construction of a radar coordinate system about the world line of an observer is discussed. Radar coordinates for a hyperbolic observer as well as a uniformly rotating observer are described in detail. The utility of the notion of radar distance and the admissibility of radar coordinates are investigated. Our results provide a critical assessment of the physical significance of radar coordinates.

  12. The Multiplexed Chemical Kinetic Photoionization Mass Spectrometer: A New Approach To Isomer-resolved Chemical Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, David L.; Zou, Peng; Johnsen, Howard; Hayden, Carl C.; Taatjes, Craig A.; Knyazev, Vadim D.; North, Simon W.; Peterka, Darcy S.; Ahmed, Musahid; Leone, Stephen R.


    We have developed a multiplexed time- and photon-energy?resolved photoionizationmass spectrometer for the study of the kinetics and isomeric product branching of gasphase, neutral chemical reactions. The instrument utilizes a side-sampled flow tubereactor, continuously tunable synchrotron radiation for photoionization, a multi-massdouble-focusing mass spectrometer with 100percent duty cycle, and a time- and positionsensitive detector for single ion counting. This approach enables multiplexed, universal detection of molecules with high sensitivity and selectivity. In addition to measurement of rate coefficients as a function of temperature and pressure, different structural isomers can be distinguished based on their photoionization efficiency curves, providing a more detailed probe of reaction mechanisms. The multiplexed 3-dimensional data structure (intensity as a function of molecular mass, reaction time, and photoionization energy) provides insights that might not be available in serial acquisition, as well as additional constraints on data interpretation.

  13. Facile synthesis of novel Ni(II)-based metal-organic coordination polymer nanoparticle/reduced graphene oxide nanocomposites and their application for highly sensitive and selective nonenzymatic glucose sensing. (United States)

    Lu, Wenbo; Qin, Xiaoyun; Asiri, Abdullah M; Al-Youbi, Abdulrahman O; Sun, Xuping


    The present paper reports on the facile preparation of novel Ni(II)-based metal-organic coordination polymer nanoparticle/reduced graphene oxide (NiCPNP/rGO) nanocomposites for the first time. The formation of the nanocomposites occurs in a single step, carried out by hydrothermal treatment of the mixture of tannic acid functioned graphene oxide and NiCl(2) aqueous solution in N,N-dimethylformamide. It is found that the NiCPNP/rGO nanocomposite-modified electrode shows high electrocatalytic activity for glucose oxidation in alkaline medium. This nonenzymatic glucose sensor exhibits high selectivity toward glucose and the linear range and limit of detection are estimated to be from 0.01 to 8.75 mM (r: 0.997) and 0.14 μM with a signal-to-noise ratio of 3, respectively. The application of this glucose sensor in human blood serum has also been demonstrated successfully.

  14. Polymorph and isomer conversion of complexes based on CuI and PPh3 easily observed via luminescence. (United States)

    Maini, Lucia; Braga, Dario; Mazzeo, Paolo P; Ventura, Barbara


    Reactions between copper(I) iodide and triphenylphosphine have been explored in solution and in the solid state and six luminescent coordination complexes have been obtained and characterized by X-ray diffraction and UV-vis spectroscopy and photophysics. Solid-state reactions of CuI with PPh(3) in different conditions (kneading, vapour digestion) and stoichiometries resulted in the formation of high ratio ligand:metal compounds while tetrameric structures could be obtained only by solution reactions. Crystal structures were determined by single crystal X-ray diffraction while purity of the bulk product was checked by powder diffraction (XRPD). Three different tetrameric structures with 1:1 stoichiometry have been synthesized: two closed cubane-type polymorphs [CuI(PPh(3))](4) (form 1a) and [CuI(PPh(3))](4) (form 1b) and an open step-like isomer [CuI(PPh(3))](4) (form 2). The conversions between the polymorphs and isomers have been studied and characterized by XRPD. The most stable form [CuI(PPh(3))](4) (form 1b) can convert into the open step-like isomer [CuI(PPh(3))](4) (form 2) in a slurry experiment with EtOH or CH(2)Cl(2) or AcCN and converts back into [CuI(PPh(3))](4)1b when exposed to vapors of toluene. At room temperature all the tetrameric compounds exhibit luminescence in the solid state and, notably, the two polymorphs show a dissimilar dual emission at low temperature. The luminescence features in the solid state seem to be peculiarly related to the presence of the aromatic phosphine ligand and depend on the Cu-Cu distance in the cluster.

  15. Differential adsorption of CHON isomers at interstellar grain surfaces (United States)

    Lattelais, M.; Pauzat, F.; Ellinger, Y.; Ceccarelli, C.


    Context. The CHON generic chemical formula covers different isomers such as isocyanic acid (HNCO), cyanic acid (HOCN), fulminic acid (HCNO), and isofulminic acid (HONC); the first three have been identified in a large variety of environments in the interstellar medium (ISM). Several phenomena could be at the origin of the observed abundances, such as different pathways of formation and destruction involving gas phase reactions with different possible activation barriers and/or surface processes depending on the local temperature and the nature of the support. Aims: The scope of this article is to shed some light on the interaction of the CHON isomers with interstellar grains as a function of the nature of the surface and to determine the corresponding adsorption energies in order to find whether this phenomenon could play a role in the abundances observed in the ISM. Methods: The question was addressed by means of numerical simulations using first principle periodic density functional theory (DFT) to represent the grain support as a solid of infinite dimension. Results: Regardless of the nature of the model surface (water ice, graphene, silica), two different classes of isomers were identified: weakly bound (HNCO and HCNO) and strongly bound (HOCN and HONC), with the adsorption energies of the latter group being about twice those of the former. The range of the adsorption energies is (from highest to lowest) HOCN > HONC > HNCO > HCNO. They are totally disconnected from the relative stabilities, which range from HNCO > HOCN > HCNO > HONC. Conclusions: The possibility of hydrogen bonding is the discriminating factor in the trapping of CHON species on grain surfaces. Whatever the environment, differential adsorption is effective and its contribution to the molecular abundances should not be ignored. The theoretical adsorption energies provided here could be profitably used for a more realistic modeling of molecule-surfaces interactions.

  16. Theoretical Study on Two C16H12O4 Isomers of Derivatives of Pagodane

    Institute of Scientific and Technical Information of China (English)

    LIU Feng-Ling; DU Ai-Ming; WANG Su-Jing


    Two C16H12O4 isomers of derivatives of pagodane were firstly reported and studied by using DFT method. Geometries, energies, and vibrational frequencies have been calculated for the two C16H12O4 isomers with pagodane-like structures at the B3LYP/6-31G** level of theory. Symmetries of isomer 1 and 2 are D2h and D2d, respectively. Heats of formation for the two C16H12O4 isomers have been estimated in this paper. According to the heats of formation, the two C16H12O4 isomers are more stable than pagodane. Heats of formation as well as the vibrational analysis indicate that the two C16H12O4 isomers enjoy sufficient stability to allow for the experi- mental preparation.

  17. An Isomer-Specific Approach to Endocrine-Disrupting Nonylphenol in Infant Food. (United States)

    Günther, Klaus; Räcker, Torsten; Böhme, Roswitha


    Nonylphenols (NPs) are persistent endocrine disruptors that are priority hazardous substances of the European Union Water Framework Directive. Their presence in the environment has caused growing concern regarding their impact on human health. Recent studies have shown that nonylphenol is ubiquitous in commercially available foodstuffs and is also present in human blood. The isomer distribution of 4-nonylphenol was analyzed by gas chromatography - mass spectrometry in 44 samples of infant food. Our study shows that the distribution of nonylphenol isomers is dependent on the foodstuff analyzed. Although some isomer groups prevail, different distributions are frequent. Variations are even found in the same food group. Nonylphenol is a complex mixture of isomers, and the estrogenic potentials of each of these isomers are very different. Consequently, to determine the potential toxicological impact of NP in food, an isomer-specific approach is necessary.

  18. Formation of melatonin and its isomer during bread dough fermentation and effect of baking. (United States)

    Yılmaz, Cemile; Kocadağlı, Tolgahan; Gökmen, Vural


    Melatonin is produced mainly by the pineal gland in vertebrates. Also, melatonin and its isomer are found in foods. Investigating the formation of melatonin and its isomer is of importance during bread dough fermentation and its degradation during baking since bread is widely consumed in high amounts. Formation of melatonin was not significant during dough fermentation. The melatonin isomer content of nonfermented dough was found to be 4.02 ng/g and increased up to 16.71 ng/g during fermentation. Lower amounts of isomer in crumb and crust than dough showed that the thermal process caused a remarkable degree of degradation in melatonin isomer. At the end of the 180 min fermentation Trp decreased by 58%. The results revealed for the first time the formation of a melatonin isomer in bread dough during yeast fermentation.

  19. Stability and electronic spectra of C76N2 isomers

    Institute of Scientific and Technical Information of China (English)

    TENG Qi-wen; WU Shi


    Study of geometries of 16 possible isomers for C76N2 based on C78(C2v) by intermediate neglect of differential overlap (INDO) series of methods indicated that the most stable geometry 25,78-C76N2 where two nitrogen atoms substitute two apexes C(25) and C(78) near the shortest X axis and Y axis formed by two hexagons and a pentagon. Electronic structures and spectra of C76N2 were investigated. The reason for the red-shift for absorptions of C76N2 compared with that of C78(C2v) is discussed.

  20. Nuclear states with anomalously large radius (size isomers)

    Energy Technology Data Exchange (ETDEWEB)

    Ogloblin, A. A.; Demyanova, A. S., E-mail:; Danilov, A. N. [National Research Center Kurchatov Institute (Russian Federation); Belyaeva, T. L. [Ciudad Universitaria, Universidad Nacional Autónoma de Meéxico (Mexico); Goncharov, S. A. [Moscow State University, Faculty of Physics (Russian Federation); Trzaska, W. [University of Jyvaäskylaä (Finland)


    Methods of determination of the nuclear excited state radii are discussed together with the recently obtained data on the states of some light nuclei having abnormally large radii (size isomers). It is shown that such states include excited neutron-halo states in {sup 9}Be, {sup 11}Be, and {sup 13}C and some alpha-cluster states in {sup 12}C, {sup 11}B, and {sup 13}C. Among the latter ones, there is the well-known Hoyle state in {sup 12}C—the structure of this state exhibit rudimentary features of alpha-particle states.

  1. Isomers of broparoestrol and antiestrogen action: comparison with tamoxifen. (United States)

    Edery, M; Barnova, A; Drosdowsky, M; Guggiari, M; Vives, C; Rudali, G


    This study compares the relative biological potencies of a known antiestrogen tamoxifen to two triarylethylene compounds which have been shown previously to be potent inhibitors of rodent mammary tumorigenesis. Based on a) uterotrophic and anti-uterotrophic tests, b) indexes of cellularity, and c) protein content, these studies indicate that the trans, as well as the cis, isomers of bromotriphenylethylene are partial estrogen antagonists with no estrogenic effects in rat uteri and partial agonists in mouse uteri, whereas tamoxifen shows partial antiestrogenic/estrogenic effects in rats and is fully estrogenic in mice.

  2. Correlation of Fe2+ isomer shifts with bond lengths and bond strengths in neso- and sorosilicates

    Institute of Scientific and Technical Information of China (English)

    李哲; E.DeGrave


    An evaluation of Mbssbauer isomer shift and quadrupole splitting data of Fe2+ in a number of structurally well characterized neso- and sorosilicates is presented. It is found that the nearly linear correlations exist both between the isomer shift and the bond length and between the isomer shift and the bond strength. These correlations are discussed on the basis of the variation of the s-electron density at the Fe2+ nuclei with the chemical bond characteristics.

  3. Polydnaviral ankyrin proteins aid parasitic wasp survival by coordinate and selective inhibition of hematopoietic and immune NF-kappa B signaling in insect hosts. (United States)

    Gueguen, Gwenaelle; Kalamarz, Marta E; Ramroop, Johnny; Uribe, Jeffrey; Govind, Shubha


    Polydnaviruses are mutualists of their parasitoid wasps and express genes in immune cells of their Lepidopteran hosts. Polydnaviral genomes carry multiple copies of viral ankyrins or vankyrins. Vankyrin proteins are homologous to IκB proteins, but lack sequences for regulated degradation. We tested if Ichnoviral Vankyrins differentially impede Toll-NF-κB-dependent hematopoietic and immune signaling in a heterologous in vivo Drosophila, system. We first show that hematopoiesis and the cellular encapsulation response against parasitoid wasps are tightly-linked via NF-κB signaling. The niche, which neighbors the larval hematopoietic progenitors, responds to parasite infection. Drosophila NF-κB proteins are expressed in the niche, and non cell-autonomously influence fate choice in basal and parasite-activated hematopoiesis. These effects are blocked by the Vankyrin I²-vank-3, but not by P-vank-1, as is the expression of a NF-κB target transgene. I²-vank-3 and P-vank-1 differentially obstruct cellular and humoral inflammation. Additionally, their maternal expression weakens ventral embryonic patterning. We propose that selective perturbation of NF-κB-IκB interactions in natural hosts of parasitic wasps negatively impacts the outcome of hematopoietic and immune signaling and this immune deficit contributes to parasite survival and species success in nature.

  4. D Coordinate Transformation Using Artificial Neural Networks (United States)

    Konakoglu, B.; Cakır, L.; Gökalp, E.


    Two coordinate systems used in Turkey, namely the ED50 (European Datum 1950) and ITRF96 (International Terrestrial Reference Frame 1996) coordinate systems. In most cases, it is necessary to conduct transformation from one coordinate system to another. The artificial neural network (ANN) is a new method for coordinate transformation. One of the biggest advantages of the ANN is that it can determine the relationship between two coordinate systems without a mathematical model. The aim of this study was to investigate the performances of three different ANN models (Feed Forward Back Propagation (FFBP), Cascade Forward Back Propagation (CFBP) and Radial Basis Function Neural Network (RBFNN)) with regard to 2D coordinate transformation. To do this, three data sets were used for the same study area, the city of Trabzon. The coordinates of data sets were measured in the ED50 and ITRF96 coordinate systems by using RTK-GPS technique. Performance of each transformation method was investigated by using the coordinate differences between the known and estimated coordinates. The results showed that the ANN algorithms can be used for 2D coordinate transformation in cases where optimum model parameters are selected.

  5. Identifying isomers of C-78 by means of x-ray spectroscopy

    DEFF Research Database (Denmark)

    Bassan, Arianna; Nyberg, Mats; Luo, Yi


    X-ray photoelectron and absorption spectra of C-78 isomers have been generated using density functional theory with inclusion of the full core-hole potentials. Strong isomer dependence has been found in absorption, but not in the photoelectron spectra. C-78 isomers can be thought to be formed...... by inserting 18 carbon atoms into an opened C-60. We have shown how the different local arrangements of these 18 carbon atoms are responsible for the significant isomer dependence observed. Our calculated spectra are in excellent agreement with the experimental counterparts....

  6. Chemical Simulations of Prebiotic Molecules: Interstellar Ethanimine Isomers (United States)

    Quan, Donghui; Herbst, Eric; Corby, Joanna F.; Durr, Allison; Hassel, George


    The E- and Z-isomers of ethanimine (CH3CHNH) were recently detected toward the star-forming region Sagittarius (Sgr) B2(N) using the Green Bank Telescope PRIMOS cm-wave spectral data, and imaged by the Australia Telescope Compact Array. Ethanimine is not reported in the hot cores of Sgr B2, but only in gas that absorbs at +64 and +82 km s-1 in the foreground of continuum emission generated by H ii regions. The ethanimine isomers can serve as precursors of the amino acid alanine and may play important roles in forming biological molecules in the interstellar medium. Here we present a study of the chemistry of ethanimine using a gas-grain simulation based on rate equations, with both isothermal and warm-up conditions. In addition, the density, kinetic temperature, and cosmic ray ionization rate have been varied. For a variety of physical conditions in the warm-up models for Sgr B2(N) and environs, the simulations show reasonable agreement with observationally obtained abundances. Isothermal models of translucent clouds along the same line of sight yield much lower abundances, so that ethanimine would be much more difficult to detect in these sources despite the fact that other complex molecules have been detected there.

  7. The prenucleosome, a stable conformational isomer of the nucleosome. (United States)

    Fei, Jia; Torigoe, Sharon E; Brown, Christopher R; Khuong, Mai T; Kassavetis, George A; Boeger, Hinrich; Kadonaga, James T


    Chromatin comprises nucleosomes as well as nonnucleosomal histone-DNA particles. Prenucleosomes are rapidly formed histone-DNA particles that can be converted into canonical nucleosomes by a motor protein such as ACF. Here we show that the prenucleosome is a stable conformational isomer of the nucleosome. It consists of a histone octamer associated with ∼ 80 base pair (bp) of DNA, which is located at a position that corresponds to the central 80 bp of a nucleosome core particle. Monomeric prenucleosomes with free flanking DNA do not spontaneously fold into nucleosomes but can be converted into canonical nucleosomes by an ATP-driven motor protein such as ACF or Chd1. In addition, histone H3K56, which is located at the DNA entry and exit points of a canonical nucleosome, is specifically acetylated by p300 in prenucleosomes relative to nucleosomes. Prenucleosomes assembled in vitro exhibit properties that are strikingly similar to those of nonnucleosomal histone-DNA particles in the upstream region of active promoters in vivo. These findings suggest that the prenucleosome, the only known stable conformational isomer of the nucleosome, is related to nonnucleosomal histone-DNA species in the cell.

  8. Direct transitions from high-K isomers to low-K bands -- {gamma} softness or coriolis coupling

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Yoshifumi R.; Narimatsu, Kanako; Ohtsubo, Shin-Ichi [Kyushu Univ., Fukuoka (Japan)] [and others


    Recent measurements of direct transitions from high-K isomers to low-K bands reveal severe break-down of the K-selection rule and pose the problem of how to understand the mechanism of such K-violation. The authors recent systematic calculations by using a simple {gamma}-tunneling model reproduced many of the observed hindrances, indicating the importance of the {gamma} softness. However, there are some data which cannot be explained in terms of the {gamma}-degree of freedom. In this talk, the authors also discuss the results of conventional Coriolis coupling calculations, which is considered to be another important mechanism.

  9. The gamma-ray spectra of 5-carbon alkane isomers in the positron annihilation process

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiaoguang, E-mail:; Zhu, Yinghao; Liu, Yang


    The gamma-ray spectra of pentane (C{sub 5}H{sub 12}) and its two isomers, i.e., 2-Methylbutane (CH{sub 3}C(CH{sub 3})HC{sub 2}H{sub 5}) and 2,2-Dimethylpropane (C(CH{sub 3}){sub 4}) have been studied theoretically in the present work. The recent experimental gamma-ray spectra of these three molecules show that they have the same Doppler shifts, although their molecular structures are dramatically different. In order to reveal why the gamma-ray spectra of these molecules are less sensitive to the molecular structures, the one-dimensional gamma-ray spectra and spherically averaged momentum (SAM) distributions, the two-dimensional angular correlation of annihilation radiation (ACAR), and the three-dimensional momentum distributions of the positron–electron pair are studied. The one-centered momentum distributions of the electrons are found to play more important role than the multi-centered coordinate distributions. The present theoretical predictions have confirmed the experimental findings for the first time. The dominance of the inner valence electrons in the positron–electron annihilation process has also been suggested in the present work. - Highlights: • The structure effects only play a minor role in the one-dimension gamma-ray spectra. • The present study further confirms the dominance of the inner valence electrons in the positron–electron annihilation process. • The momentum distributions of the electrons play more important role than the coordinate distributions.

  10. Cyclodextrin-Based Metal-Organic Nanotube as Fluorescent Probe for Selective Turn-On Detection of Hydrogen Sulfide in Living Cells Based on H2S-Involved Coordination Mechanism. (United States)

    Xin, Xuelian; Wang, Jingxin; Gong, Chuanfang; Xu, Hai; Wang, Rongming; Ji, Shijie; Dong, Hanxiao; Meng, Qingguo; Zhang, Liangliang; Dai, Fangna; Sun, Daofeng


    Hydrogen sulfide (H2S) has been considered as the third biologically gaseous messenger (gasotransmitter) after nitric oxide (NO) and carbon monoxide (CO). Fluorescent detection of H2S in living cells is very important to human health because it has been found that the abnormal levels of H2S in human body can cause Alzheimer's disease, cancers and diabetes. Herein, we develop a cyclodextrin-based metal-organic nanotube, CD-MONT-2, possessing a {Pb14} metallamacrocycle for efficient detection of H2S. CD-MONT-2' (the guest-free form of CD-MONT-2) exhibits turn-on detection of H2S with high selectivity and moderate sensitivity when the material was dissolved in DMSO solution. Significantly, CD-MONT-2' can act as a fluorescent turn-on probe for highly selective detection of H2S in living cells. The sensing mechanism in the present work is based on the coordination of H2S as the auxochromic group to the central Pb(II) ion to enhance the fluorescence intensity, which is studied for the first time.

  11. Synthesis of Framework Isomer MOFs Containing Zinc and 4-Tetrazolyl Benzenecarboxylic Acid via a Structure Directing Solvothermal Approach

    Directory of Open Access Journals (Sweden)

    Carlos Ordonez


    Full Text Available The solvothermal synthesis of framework isomers was carried out using the hybrid carboxylate and tetrazolate functional ligand, 4-tetrazolyl benzenecarboxylic acid (H2TBC, TBC = 4-tetrazolyl benzenecarboxylate and zinc. H2TBC was also synthesized with the solvothermal approach, and is referred herein as structure 1. Using single-crystal X-ray diffraction, we found that the tetrazolate groups of TBC show an unusual “opposite-on” coordination mode with zinc. Three previously characterized metal-organic frameworks (MOFs were obtained by systematically changing the solvents of the H2TBC-Zn reaction, (1 ZnTBC, 2, which has a non-porous structure; (2 Zn2(TBC2(H2O, 3, which has an amphiphilic pore structure and (3 Zn2(TBC2{guest}, 4, which is porous and has channels containing uncoordinated N heteroatoms. Fluorescence spectra of 4 reveal a strong blue emission mainly from the TBC ligands.

  12. Graphene-ZIF8 composite material as stationary phase for high-resolution gas chromatographic separations of aliphatic and aromatic isomers. (United States)

    Yang, Xiaohong; Li, Changxia; Qi, Meiling; Qu, Liangti


    This work presents the separation performance of graphene-ZIF8 (G-Z) composite material as stationary phase for capillary gas chromatography (GC). The G-Z stationary phase achieved high column efficiency of 5000 plates/m determined by n-dodecane (k=1.22) at 120°C and showed weakly polar nature. Importantly, it exhibited high selectivity and resolving capability for branched alkane isomers and aromatic positional isomers, showing clear advantages over the reported neat graphene and ZIF8. In addition, it attained high resolution for geometric cis-/trans-isomers. The G-Z column exhibited good column thermal stability up to 300°C and column repeatability with RSD values of retention times in the range of 0.01-0.19% for intra-day, 0.05-0.88% for inter-day and 0.66-5.6% for between-column, respectively, Moreover, the G-Z column was employed for the determination of minor impurity isomers in real reagent samples, which demonstrates its promising potential in GC applications.

  13. Analysis of gamma irradiated pepper constituents, 4. Analysis of piperine and its isomers by reversed phase HPLC and effect of gamma irradiation on isomerization of piperine

    Energy Technology Data Exchange (ETDEWEB)

    Takagi, Kazuko; Ochiai, Junko; Okuyama, Tsuneo


    A separation method for piperine and its isomers (isopiperine, isochavicine and chavicine) was investigated. These isomers were produced from piperine with irradiation. This reaction is photochemical isomerization. Piperine and its isomers were separated on a reversed phase C/sub 8/ (LiChrospher 300 RP-8 10 um 0.4 I.D. x 0.4 cm and LiChrosorb RP-8 SelectB 0.4 I.D. x 25 cm) column with a mixture of 0.1% trifluoroacetic acid (TFA) in water and 75% acetonitrile-0.1% TFA in water (92 : 8) and detected at 210 nm, 280 nm. By this method, four peaks derivded from piperine and its isomers were recognized. Piperine was identified by addition of piperine as a internal standard. Unknown peaks were fractionated by chromatography on the column for NMR structural identification. Isochavicine was identified by NMR. And the other peaks were presumed by the fact that chavicine dose not produce from piperine with mild irradiation condition. In contrast of photochemical isomerization, the effect of gamma irradiation on isomerization of piperine was investigated by HPLC analysis. Gamma irradiation had no effect on the isomerization of piperine.

  14. Movement and Coordination (United States)

    ... Español Text Size Email Print Share Movement and Coordination Page Content Article Body At this age, your ... level will strengthen his body and develop his coordination. In the months ahead, your child’s running will ...

  15. Developmental coordination disorder (United States)

    ... page: // Developmental coordination disorder To use the sharing features on this page, please enable JavaScript. Developmental coordination disorder is a childhood disorder. It leads to ...

  16. Assigning Peptide Disulfide Linkage Pattern Among Regio-Isomers via Methoxy Addition to Disulfide and Tandem Mass Spectrometry. (United States)

    Durand, Kirt L; Tan, Lei; Stinson, Craig A; Love-Nkansah, Chasity B; Ma, Xiaoxiao; Xia, Yu


    Pinpointing disulfide linkage pattern is critical in the characterization of proteins and peptides consisting of multiple disulfide bonds. Herein, we report a method based on coupling online disulfide modification and tandem mass spectrometry (MS/MS) to distinguish peptide disulfide regio-isomers. Such a method relies on a new disulfide bond cleavage reaction in solution, involving methanol as a reactant and 254 nm ultraviolet (UV) irradiation. This reaction leads to selective cleavage of a disulfide bond and formation of sulfenic methyl ester (-SOCH3) at one cysteine residue and a thiol (-SH) at the other. Under low energy collision-induced dissociation (CID), cysteine sulfenic methyl ester motif produces a signature methanol loss (-32 Da), allowing its identification from other possible isomeric structures such as S-hydroxylmethyl (-SCH2OH) and methyl sulfoxide (-S(O)-CH3). Since disulfide bond can be selectively cleaved and modified upon methoxy addition, subsequent MS(2) CID of the methoxy addition product provides enhanced sequence coverage as demonstrated by the analysis of bovine insulin. More importantly, this reaction does not induce disulfide scrambling, likely due to the fact that radical intermediates are not involved in the process. An approach based on methoxy addition followed by MS(3) CID has been developed for assigning disulfide linkage patterns in peptide disulfide regio-isomers. This methodology was successfully applied to characterizing peptide systems having two disulfide bonds and three disulfide linkage isomers: side-by-side, overlapped, and looped-within-a-loop configurations. Graphical Abstract ᅟ.

  17. Coordination and Cooperation


    Janssen, Maarten


    textabstractThis comment makes four related points. First, explaining coordination is different from explaining cooperation. Second, solving the coordination problem is more important for the theory of games than solving the cooperation problem. Third, a version of the Principle of Coordination can be rationalized on individualistic grounds. Finally, psychological game theory should consider how players perceive their gaming situation. ---------------------------------------------------------...

  18. Processing Coordination Ambiguity (United States)

    Engelhardt, Paul E.; Ferreira, Fernanda


    We examined temporarily ambiguous coordination structures such as "put the butter in the bowl and the pan on the towel." Minimal Attachment predicts that the ambiguous noun phrase "the pan" will be interpreted as a noun-phrase coordination structure because it is syntactically simpler than clausal coordination. Constraint-based theories assume…

  19. Processing Coordination Ambiguity (United States)

    Engelhardt, Paul E.; Ferreira, Fernanda


    We examined temporarily ambiguous coordination structures such as "put the butter in the bowl and the pan on the towel." Minimal Attachment predicts that the ambiguous noun phrase "the pan" will be interpreted as a noun-phrase coordination structure because it is syntactically simpler than clausal coordination. Constraint-based…

  20. Coordination and Cooperation

    NARCIS (Netherlands)

    M.C.W. Janssen (Maarten)


    textabstractThis comment makes four related points. First, explaining coordination is different from explaining cooperation. Second, solving the coordination problem is more important for the theory of games than solving the cooperation problem. Third, a version of the Principle of Coordination can

  1. Coordination and Cooperation

    NARCIS (Netherlands)

    M.C.W. Janssen (Maarten)


    textabstractThis comment makes four related points. First, explaining coordination is different from explaining cooperation. Second, solving the coordination problem is more important for the theory of games than solving the cooperation problem. Third, a version of the Principle of Coordination can

  2. The behaviour of EDDHA isomers in soils as influenced by soil properties.

    NARCIS (Netherlands)

    Schenkeveld, W.D.C.; Reichwein, A.M.; Temminghoff, E.J.M.; Riemsdijk, van W.H.


    FeEDDHA products are applied to correct iron chlorosis in plants and consist of a mixture of EDDHA isomers chelated to iron. In this study such mixtures have been divided into four (groups of) isomers: racemic o,o-EDDHA, meso o,o-EDDHA, o,p-EDDHA and rest-EDDHA. The physical and chemical properties

  3. Structures and stability of isomers of [Si,N,N,P] system

    Institute of Scientific and Technical Information of China (English)

    KAN Wei; YU Haitao; LI Mingxia; FU Honggang; SUN Jiazhong


    Some stationary points on the potential energy surface of [Si, N, N, P] system were located at the B3LYP/6-311G(d) and QCISD(t)/6-311+G(2df)(single-point) levels of theory, while the isomerization, structures, and stability of these obtained isomers were suggested. The computed results indicate that only four-membered ring isomer SiNPN(E1, 2A"), which possesses butterfly-like structure and Si-P cross bonding, is kinetically stable in all optimized isomers. Other isomers may be considered as kinetically unstable towards isomerization or dissociation because of the corresponding smaller reaction barriers. Furthermore, the present paper also proposes electronic and geometric structures, vibrational frequencies and the corresponding vibrational modes, dipole moments, and rotational constants of isomer E1. To make use of the computed results, we can clearly know that the reaction pathway via an intermediate E3 (SiNPN) is the most favorable channel producing isomer E1 from fragments SiN (2∏) and PN (1∑), which have been well characterized in space, and thus, isomer E1 can be considered as a candidate for interstellar observation. The reaction enthalpy of SiN (2∏) + pN(1∑)→E1 and the standard enthalpy of formation of isomer E1 are 215.25 and 457.99 k J/mol, respectively, at 298.15 K.

  4. Quantification of minerals and tocopherols isomers in chestnuts approach chemometrics

    Directory of Open Access Journals (Sweden)

    Nilson Evelazio de Souza


    Full Text Available The levels of the ?, ?, and (?+?-tocopherol isomers and the amounts of the minerals Se, Zn, Ca, Fe, K, Mn, Mg, and Cu were analyzed in chestnuts. High contents of Zn (>65% relative to the recommended dietary intake (RDI were found in all chestnuts except macadamia nuts (25% of the RDI. All samples had Se contents higher than the RDI: Brazil nuts > macadamia nuts, cashew nuts > pecans > almonds > pistachio nuts > hazelnuts > European nuts. A greater concentration of ?-tocopherol was found in almonds (30% of RDI. All samples, except for hazelnuts, almonds, and macadamia nuts, had (?+?- tocopherols, with the largest amount found in pistachios. Only pecan nuts and European nuts had ?-tocopherol and only in low amounts. Multivariate analysis allowed for better characterization and distinction of the chestnuts

  5. Synthesis and Applications of Hajos-Parrish Ketone Isomers. (United States)

    Eagan, James M; Hori, Masahiro; Wu, Jianbin; Kanyiva, Kyalo Stephen; Snyder, Scott A


    Numerous natural products possess ring systems and functionality for which Hajos-Parrish ketone isomers with a transposed methyl group (termed "iso-Hajos-Parrish ketones") would be of value. However, such building blocks have not been exploited to the same degree as the more typical Hajos-Parrish hydrindane. An efficient three-step synthesis of such materials was fueled by a simple method for the rapid preparation of highly functionalized cyclopentenones, several of which are new chemical entities that would be challenging to access through other approaches. Furthermore, one iso-Hajos-Parrish ketone was converted into two distinct natural product analogues and one natural product. As one indication of the value of these new building blocks, that latter target was obtained in 10 steps, having previously been accessed in 18 steps using the Hajos-Parrish ketone. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Electronic Single Molecule Identification of Carbohydrate Isomers by Recognition Tunneling

    CERN Document Server

    Im, JongOne; Liu, Hao; Zhao, Yanan; Sen, Suman; Biswas, Sudipta; Ashcroft, Brian; Borges, Chad; Wang, Xu; Lindsay, Stuart; Zhang, Peiming


    Glycans play a central role as mediators in most biological processes, but their structures are complicated by isomerism. Epimers and anomers, regioisomers, and branched sequences contribute to a structural variability that dwarfs those of nucleic acids and proteins, challenging even the most sophisticated analytical tools, such as NMR and mass spectrometry. Here, we introduce an electron tunneling technique that is label-free and can identify carbohydrates at the single-molecule level, offering significant benefits over existing technology. It is capable of analyzing sub-picomole quantities of sample, counting the number of individual molecules in each subset in a population of coexisting isomers, and is quantitative over more than four orders of magnitude of concentration. It resolves epimers not well separated by ion-mobility and can be implemented on a silicon chip. It also provides a readout mechanism for direct single-molecule sequencing of linear oligosaccharides.

  7. Energetics of cyclohexane isomers: a density-functional study

    CERN Document Server

    Lee, C Y


    The binding energies and the geometric structures of conformational isomers of cyclohexane (C sub 6 H sub 1 sub 2) are determined from the density-functional theory combined with ultrasoft pseudopotentials and gradient-corrected nonlocal exchange-correlation functionals. The ground-state chair conformation is found to have a binding energy of 99.457 eV, and the metastable twist-boat conformation has 99.161 eV. The chair conformation converts to another conformation via a half-chair conformation with an energy barrier of 0.507 eV whereas the twist-boat conformation converts to another twist-boat conformation via a boat conformation with a much smaller energy barrier of 0.015 eV.

  8. Electronic Structure and Stability of C20 Isomers

    Institute of Scientific and Technical Information of China (English)



    The electronic structure of the C20 cluster in monocyclic ring, bowl and fullerene isomers has been calculated using the tight-binding scheme developed by Harrison, starting in particular from the sp2.803-hybrids for the fullerene structure. The study of energetics predicts the fullerene to be the ground state with the bowl and ring lying over 1.32 and 3.35 eV higher in energy. The total energies will be lowered by Peierls or Jahn-Teller distortion, but the energetic ordering remains unchanged. It is also shown that the range of valence electron, the level difference between the highest occupied molecular orbital and the lowest unoccupied molecular orbital as well as the σ - π gap, which are less sensitive to the exact geometry, vary in the ring, bowl and fullerene sequence.

  9. Communication: "Position" does matter: The photofragmentation of the nitroimidazole isomers (United States)

    Bolognesi, P.; Casavola, A. R.; Cartoni, A.; Richter, R.; Markus, P.; Borocci, S.; Chiarinelli, J.; Tošić, S.; Sa'adeh, H.; Masič, M.; Marinković, B. P.; Prince, K. C.; Avaldi, L.


    A combined experimental and theoretical approach has been used to disentangle the fundamental mechanisms of the fragmentation of the three isomers of nitroimidazole induced by vacuum ultra-violet (VUV) radiation, namely, 4-, 5-, and 2-nitroimidazole. The results of mass spectrometry as well as photoelectron-photoion coincidence spectroscopy display striking differences in the radiation-induced decomposition of the different nitroimidazole radical cations. Based on density functional theory (DFT) calculations, a model is proposed which fully explains such differences, and reveals the subtle fragmentation mechanisms leading to the release of neutral species like NO, CO, and HCN. Such species have a profound impact in biological media and may play a fundamental role in radiosensitising mechanisms during radiotherapy.

  10. Metabolic engineering of Saccharomyces cerevisiae for production of butanol isomers. (United States)

    Generoso, Wesley Cardoso; Schadeweg, Virginia; Oreb, Mislav; Boles, Eckhard


    Saccharomyces cerevisiae has decisive advantages in industrial processes due to its tolerance to alcohols and fermentation conditions. Butanol isomers are considered as suitable fuel substitutes and valuable biomass-derived chemical building blocks. Whereas high production was achieved with bacterial systems, metabolic engineering of yeast for butanol production is in the beginning. For isobutanol synthesis, combination of valine biosynthesis and degradation, and complete pathway re-localisation into cytosol or mitochondria gave promising results. However, competing pathways, co-factor imbalances and FeS cluster assembly are still major issues. 1-Butanol production via the Clostridium pathway seems to be limited by cytosolic acetyl-CoA, its central precursor. Endogenous 1-butanol pathways have been discovered via threonine or glycine catabolism. 2-Butanol production was established but was limited by B12-dependence.

  11. Submolecular imaging of chloronitrobenzene isomers on Cu(111) (United States)

    Niemi, Eeva; Simic-Milosevic, Violeta; Morgenstern, Karina; Korventausta, Antti; Paavilainen, Sami; Nieminen, Jouko


    We compare computer simulations to experimental scanning tunneling microscopy (STM) images of chloronitrobenzene molecules on a Cu(111) surface. The experiments show that adsorption induced isomerization of the molecules takes place on the surface. Furthermore, not only the submolecular features can be seen in the STM images, but different isomers can also be recognized. The Todorov-Pendry approach to tunneling produces simulated STM images which are in good accordance with the experiments. Alongside with STM simulations in a tight-binding basis, ab initio calculations are performed in order to analyze the symmetry of relevant molecular orbitals and to consider the nature of tunneling channels. Our calculations show that while the orbitals delocalized to the phenyl ring create a relatively transparent tunneling channel, they also almost isolate the orbitals of the substitute groups at energies which are relevant in STM experiments. These features of the electronic structure are the key ingredients of the accurate submolecular observations.

  12. Enantiomers of a nonylphenol isomer: absolute configurations and estrogenic potencies. (United States)

    Zhang, Haifeng; Oppel, Iris M; Spiteller, Michael; Guenther, Klaus; Boehmler, Gabriele; Zuehlke, Sebastian


    Enantiomers of 4-(1,1,2-trimethylhexyl)phenol, a chiral isomer of the endocrine disrupting chemical nonylphenol, have been resolved and isolated by preparative chiral HPLC. The absolute configurations of the enantiomers were then determined by an X-ray crystallographic study of the (-)-camphanoyl derivative of the first eluted enantiomer NP(35)E1. The first enantiomer (NP(35)E1) and the second enantiomer (NP(35)E2) eluted were found to have the S and R absolute configurations, respectively. The estrogenic potencies of the S and R enantiomers were tested by the E-screen assay. A slight difference was observed in the relative proliferative effect between the S enantiomer and R enantiomer in the E-screen assay.

  13. Coordinating Group report

    Energy Technology Data Exchange (ETDEWEB)


    In December 1992, western governors and four federal agencies established a Federal Advisory Committee to Develop On-site Innovative Technologies for Environmental Restoration and Waste Management (the DOIT Committee). The purpose of the Committee is to advise the federal government on ways to improve waste cleanup technology development and the cleanup of federal sites in the West. The Committee directed in January 1993 that information be collected from a wide range of potential stakeholders and that innovative technology candidate projects be identified, organized, set in motion, and evaluated to test new partnerships, regulatory approaches, and technologies which will lead to improve site cleanup. Five working groups were organized, one to develop broad project selection and evaluation criteria and four to focus on specific contaminant problems. A Coordinating Group comprised of working group spokesmen and federal and state representatives, was set up to plan and organize the routine functioning of these working groups. The working groups were charged with defining particular contaminant problems; identifying shortcomings in technology development, stakeholder involvement, regulatory review, and commercialization which impede the resolution of these problems; and identifying candidate sites or technologies which could serve as regional innovative demonstration projects to test new approaches to overcome the shortcomings. This report from the Coordinating Group to the DOIT Committee highlights the key findings and opportunities uncovered by these fact-finding working groups. It provides a basis from which recommendations from the DOIT Committee to the federal government can be made. It also includes observations from two public roundtables, one on commercialization and another on regulatory and institutional barriers impeding technology development and cleanup.

  14. ITMS capabilities in isomer analysis. Part 3. Characterisation of methyl and dimethyl derivatives of 8-desmethylseseline, potential anti-proliferative agents, by tandem mass spectrometry (United States)

    Kiremire, B.; Traldi, P.; Guiotto, A.; Pastorini, G.; Chilin, A.; Vettori, U.


    Two sets of isomeric pyranocoumarins and pyranochromones have been studied by both electron impact and collision-induced dissociation. The daughter spectra were obtained by ion trap mass spectrometry experiments. Characteristic fragments were obtained in electron impact that allowed differentiation between the chromone and the coumarin systems. Distinction between isomers in each set was achieved by collision-induced daughter spectra of selected parent ions.

  15. Structures and stability of isomers of [C,N,N,P] system

    Institute of Scientific and Technical Information of China (English)

    KAN Wei; ZHONG Hua; YU Haitao; FU Honggang; SUN Jiazhong


    Nine isomers, twenty transition states, and some relative dissociation fragments of [C,N,N,P] system were located at the B3LYP/6-311G(d) and QCISD(t)/6-311+G(2df) (single-point) levels of theory, and the isomerization, structures, and stability of these obtained isomers were suggested. The results indicate that four nonlinear chainlike isomers NCNP, NCPN, CNPN, and CNNP with 2A′ electronic state are kinetically stable. Other isomers are kinetically unstable towards isomerization or dissociation because of the corresponding smaller reaction barriers. Furthermore, calculated vibrational frequencies, rotational constants, dipole moments, the first adiabatic ionization energies, and adiabatic electron affinities of the four isomers may provide some theoretical information that is helpful for identifying their existence in future laboratory and interstellar investigations. The results are also compared with [Si,N,N,P] system.

  16. Lipid and Glycolipid Isomer Analyses Using Ultra-High Resolution Ion Mobility Spectrometry Separations

    Energy Technology Data Exchange (ETDEWEB)

    Wojcik, Roza; Webb, Ian; Deng, Liulin; Garimella, Sandilya; Prost, Spencer; Ibrahim, Yehia; Baker, Erin; Smith, Richard


    Understanding the biological mechanisms related to lipids and glycolipids is challenging due to the vast number of possible isomers. Mass spectrometry (MS) measurements are currently the dominant approach for studying and providing detailed information on lipid and glycolipid structures. However, difficulties in distinguishing many structural isomers (e.g. distinct acyl chain positions, double bond locations, as well as glycan isomers) inhibit the understanding of their biological roles. Here we utilized ultra-high resolution ion mobility spectrometry (IMS) separations based upon the use of traveling waves in a serpentine long path length multi-pass Structures for Lossless Manipulations (SLIM) to enhance isomer resolution. The multi-pass arrangement allowed separations ranging from ~16 m (1 pass) to ~470 m (32 passes) to be investigated for the distinction of lipids and glycolipids with extremely small structural differences. These ultra-high resolution SLIM IMS-MS analyses provide a foundation for exploring and better understanding isomer specific biological and disease processes.

  17. Aqueous phase partitioning of hexachlorocyclohexane (HCH) isomers by biosurfactant produced by Pseudomonas aeruginosa WH-2

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Suman; Singh, Partapbir [Department of Microbiology, Guru Nanak Dev University, Amritsar 143005, Punjab (India); Raj, Mayil [MTCC, IMTECH, Sector 39-A, Chandigarh 160036 (India); Chadha, Bhupinder Singh [Department of Microbiology, Guru Nanak Dev University, Amritsar 143005, Punjab (India); Saini, Harvinder Singh, E-mail: [Department of Microbiology, Guru Nanak Dev University, Amritsar 143005, Punjab (India)


    The different isomers of technical-grade hexachlorocyclohexane (t-HCH) including the insecticidal {gamma}-isomer, commonly known as lindane, have been reported to be toxic, carcinogenic and endocrine disrupters. The spatial arrangements of the chlorine atoms on different isomers and low aqueous phase solubility contribute to their persistence in environment, {beta}-HCH being the most resistance to transformation. The biosurfactant preparation of Pseudomonas aeruginosa isolate WH-2 was evaluated for its ability to improve the aqueous phase partitioning of different isomers of HCH-muck. Further, the ability of biosurfactant preparation to emulsify HCH and n-hexadecane was checked under different conditions, usually characteristic of sites contaminated with pollutants viz. wide range of pH, temperature, and salinity. The data obtained from this study will be helpful in designing suitable bioremediation strategies for huge stock piles of HCH-muck and sites polluted by reckless use/disposal of HCH-isomers.

  18. Comparative Autoignition Trends in Butanol Isomers at Elevated Pressure

    KAUST Repository

    Weber, Bryan W.


    Autoignition experiments of stoichiometric mixtures of s-, t-, and i-butanol in air have been performed using a heated rapid compression machine (RCM). At compressed pressures of 15 and 30 bar and for compressed temperatures in the range 715-910 K, no evidence of a negative temperature coefficient region in terms of ignition delay response is found. The present experimental results are also compared with previously reported RCM data of n-butanol in air. The order of reactivity of the butanols is n-butanol > s-butanol ≈ i-butanol > t-butanol at the lower pressure but changes to n-butanol > t-butanol > s-butanol > i-butanol at higher pressure. In addition, t-butanol shows preignition heat release behavior, which is especially evident at higher pressures. To help identify the controlling chemistry leading to this preignition heat release, off-stoichiometric experiments are further performed at 30 bar compressed pressure, for t-butanol at φ = 0.5 and φ = 2.0 in air. For these experiments, higher fuel loading (i.e., φ = 2.0) causes greater preignition heat release (as indicated by greater pressure rise) than the stoichiometric or φ = 0.5 cases. Comparison of the experimental ignition delays with the simulated results using two literature kinetic mechanisms shows generally good agreement, and one mechanism is further used to explore and compare the fuel decomposition pathways of butanol isomers. Using this mechanism, the importance of peroxy chemistry in the autoignition of the butanol isomers is highlighted and discussed. © 2013 American Chemical Society.

  19. Temperature Effects on the Dissociative Electron Attachment to Dichlorobenzene Isomers (United States)

    Mahmoodi-Darian, M.; Mauracher, A.; Aleem, A.; Denifl, S.; Rittenschober, B.; Bacher, A.; Probst, M.; Märk, T. D.; Scheier, P.


    Dissociative electron attachment to all three isomers of dichlorobenzene has been investigated in the electron energy range from 0 to 2 eV and in the gas temperature range from 391 to 696 K using a crossed electron-molecular beam apparatus with a new temperature-regulated effusive molecular beam source. In the case of the dissociative electron attachment channel Cl-/1,2-dichlorobenzene and Cl-/1,4-dichlorobenzene, strong enhancement of the negative ion production with the gas temperature at low electron energies has been observed. The low-energy peak increases dramatically when the gas temperature is raised from 391 to 696 K. Activation energies for dissociative electron attachment of (482 ± 20) meV for 1,2-dichlorobenzene and (59 ± 20) meV for 1,4-dichlorobenzene have been determined. For the resonance at (0.49 ± 0.03) eV in 1,2-dichlorobenzene and (0.32 ± 0.03) eV in 1,4-dichlorobenzene, no dependence of the cross sections on the gas temperature has been observed. In the case of the dissociative electron attachment to Cl-/1,3-dichlorobenzene, the cross section does not depend on the temperature in the electron energy range from 0 to 2 eV. Quantum chemical calculations of the reaction energies and of the potential energy curves involved in the dissociation of Cl- have been performed, together with an analysis of the thermo dynamical accessibility of the relevant vibrational modes. Possible reasons for the different temperature dependences of the isomers are discussed.

  20. Strategies to distinguish new synthetic cannabinoid FUBIMINA (BIM-2201) intake from its isomer THJ-2201: metabolism of FUBIMINA in human hepatocytes. (United States)

    Diao, Xingxing; Scheidweiler, Karl B; Wohlfarth, Ariane; Zhu, Mingshe; Pang, Shaokun; Huestis, Marilyn A

    Since 2013, a new drugs-of-abuse trend attempts to bypass drug legislation by marketing isomers of scheduled synthetic cannabinoids (SCs), e.g., FUBIMINA (BIM-2201) and THJ-2201. It is much more challenging to confirm a specific isomer's intake and distinguish it from its structural analog because the isomers and their major metabolites usually have identical molecular weights and display the same product ions. Here, we investigated isomers FUBIMINA and THJ-2201 and propose strategies to distinguish their consumption. THJ-2201 was scheduled in the US, Japan, and Europe; however, FUBIMINA is easily available on the Internet. We previously investigated THJ-2201 metabolism in human hepatocytes, but human FUBIMINA metabolism is unknown. We aim to characterize FUBIMINA metabolism in human hepatocytes, recommend optimal metabolites to confirm its consumption, and propose strategies to distinguish between intakes of FUBIMINA and THJ-2201. FUBIMINA (10 μM) was incubated in human hepatocytes for 3 h, and metabolites were characterized with high-resolution mass spectrometry (HR-MS). We identified 35 metabolites generated by oxidative defluorination, further carboxylation, hydroxylation, dihydrodiol formation, glucuronidation, and their combinations. We recommend 5'-OH-BIM-018 (M34), BIM-018 pentanoic acid (M33), and BIM-018 pentanoic acid dihydrodiol (M7) as FUBIMINA specific metabolites. THJ-2201 produced specific metabolite markers 5'-OH-THJ-018 (F26), THJ-018 pentanoic acid (F25), and hydroxylated THJ-2201 (F13). Optimized chromatographic conditions to achieve different retention times and careful selection of specific product ion spectra enabled differentiation of isomeric metabolites, in this case FUBIMINA from THJ-2201. Our HR-MS approach should be applicable for differentiating future isomeric SCs, which is especially important when different isomers have different legal status.

  1. Study of Molecular-Shape Selectivity of Zeolites by Gas Chromatography (United States)

    Chao, Pei-Yu; Chuang, Yao-Yuan; Ho, Grace Hsiuying; Chuang, Shiow-Huey; Tsai, Tseng-Chang; Lee, Chi-Young; Tsai, Shang-Tien; Huang, Jun-Fu


    A sorption experiment using a gas chromatograph is described that can help students understand the "molecular-shape selectivity" behavior of zeolites in the subnano regime. Hexane isomers are used as probe molecules to demonstrate the sorption phenomena. In the experiment, a zeolite adsorbs certain hexane isomers with molecular sizes smaller than…

  2. Membrane Materials and Technology for Xylene Isomers Separation and Isomerization via Pervaporation

    KAUST Repository

    Bilaus, Rakan


    P-xylene is one of the highly influential commodities in the petrochemical industry. It is used to make 90% of the world’s third largest plastic production, polyethylene terephthalate (PET). With a continuously increasing demand, the current technology’s high energy intensity has become a growing concern. Membrane separation technology is a potential low-energy alternative. Polymeric membranes were investigated in a pervaporation experiment to separate xylene isomers. Polymers of intrinsic microporosity (PIMs) as well as polyimides (PIM-PI), including thermally cross-linked PIM-1, PIM-6FDA-OH and thermally-rearranged PIM-6FDA-OH were investigated as potential candidates. Although they exhibited extremely high permeability to xylenes, selectivity towards p-xylene was poor. This was attributed to the polymers low chemical resistance which was apparent in their strong tendency to swell in xylenes. Consequently, a perfluoro-polymer, Teflon AF 2400, with a high chemical resistance was tested, which resulted in a slightly improved selectivity. A super acid sulfonated perfluoro-polymer (Nafion-H) was used as reactive membrane for xylenes isomerization. The membrane exhibited high catalytic activity, resulting in 19.5% p-xylene yield at 75ᵒC compared to 20% p-xylene yield at 450ᵒC in commercial fixed bed reactors. Nafion-H membrane outperforms the commercial technology with significant energy savings.

  3. Quantitative solid phase microextraction--gas chromatography mass spectrometry analysis of five megastigmatrienone isomers in aged wine. (United States)

    Slaghenaufi, Davide; Perello, Marie-Claire; Marchand-Marion, Stéphanie; Tempere, Sophie; de Revel, Gilles


    Megastigmatrienone is a key flavor compound in tobacco. It has also been detected in wine, where it may contribute to a tobacco/incense aroma, but its importance and concentration in wines had never previously been evaluated. A method was developed and validated for quantifying the five megastigmatrienone isomers in red and white wines. Megastigmatrienone isomers were extracted by headspace solid-phase microextraction (HS-SPME), with a 65 μm film thickness polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber and analyzed using gas chromatography-mass spectrometry (GC/MS) in selected ion monitoring mode (SIM). Several parameters affecting the length of the adsorption process (i.e., adding salt, extraction time and extraction temperature) were tested. The optimum analytical conditions were established. The LOQ were between 0.06 μg L(-1) and 0.49 μg L(-1) for white wine and 0.11 μg L(-1) and 0.98 μg L(-1) for red wine, repeatability in both types of wine was less than 10% and recovery ranged from 96% for white wine to 94% for red wine. The five isomers of megastigmatrienone were quantified in red and white wines for the first time. Concentrations ranged from 2 μg L(-1) to 41 μg L(-1) in both red and white wines. Initial results revealed a link between wine aging and megastigmatrienone levels, indicating that megastigmatrienone may be a component in wine "bouquet". Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Analysis and deconvolution of dimethylnaphthalene isomers using gas chromatography vacuum ultraviolet spectroscopy and theoretical computations. (United States)

    Schenk, Jamie; Mao, James X; Smuts, Jonathan; Walsh, Phillip; Kroll, Peter; Schug, Kevin A


    An issue with most gas chromatographic detectors is their inability to deconvolve coeluting isomers. Dimethylnaphthalenes are a class of compounds that can be particularly difficult to speciate by gas chromatography - mass spectrometry analysis, because of their significant coelution and similar mass spectra. As an alternative, a vacuum ultraviolet spectroscopic detector paired with gas chromatography was used to study the systematic deconvolution of mixtures of coeluting isomers of dimethylnaphthalenes. Various ratio combinations of 75:25; 50:50; 25:75; 20:80; 10:90; 5:95; and 1:99 were prepared to test the accuracy, precision, and sensitivity of the detector for distinguishing overlapping isomers that had distinct, but very similar absorption spectra. It was found that, under reasonable injection conditions, all of the pairwise overlapping isomers tested could be deconvoluted up to nearly two orders of magnitude (up to 99:1) in relative abundance. These experimental deconvolution values were in agreement with theoretical covariance calculations performed for two of the dimethylnaphthalene isomers. Covariance calculations estimated high picogram detection limits for a minor isomer coeluting with low to mid-nanogram quantity of a more abundant isomer. Further characterization of the analytes was performed using density functional theory computations to compare theory with experimental measurements. Additionally, gas chromatography - vacuum ultraviolet spectroscopy was shown to be able to speciate dimethylnaphthalenes in jet and diesel fuel samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Enhanced time overcurrent coordination

    Energy Technology Data Exchange (ETDEWEB)

    Enriquez, Arturo Conde; Martinez, Ernesto Vazquez [Universidad Autonoma de Nuevo Leon, Facultad de Ingenieria Mecanica y Electrica, Apdo. Postal 114-F, Ciudad Universitaria, CP 66450 San Nicolas de los Garza, Nuevo Leon (Mexico)


    In this paper, we recommend a new coordination system for time overcurrent relays. The purpose of the coordination process is to find a time element function that allows it to operate using a constant back-up time delay, for any fault current. In this article, we describe the implementation and coordination results of time overcurrent relays, fuses and reclosers. Experiments were carried out in a laboratory test situation using signals of a power electrical system physics simulator. (author)

  6. Scalable Social Coordination using Enmeshed Queries

    CERN Document Server

    Chen, Jianjun; Varghese, George


    Social coordination allows users to move beyond awareness of their friends to efficiently coordinating physical activities with others. While specific forms of social coordination can be seen in tools such as Evite, Meetup and Groupon, we introduce a more general model using what we call {\\em enmeshed queries}. An enmeshed query allows users to declaratively specify an intent to coordinate by specifying social attributes such as the desired group size and who/what/when, and the database returns matching queries. Enmeshed queries are continuous, but new queries (and not data) answer older queries; the variable group size also makes enmeshed queries different from entangled queries, publish-subscribe systems, and dating services. We show that even offline group coordination using enmeshed queries is NP-hard. We then introduce efficient heuristics that use selective indices such as location and time to reduce the space of possible matches; we also add refinements such as delayed evaluation and using the relative...

  7. Systematic Investigation of Benzodithiophene-Benzothiadiazole Isomers for Organic Photovoltaics. (United States)

    Du, Jia; Fortney, Andria; Washington, Katherine E; Bulumulla, Chandima; Huang, Peishen; Dissanayake, Dushanthi; Biewer, Michael C; Kowalewski, Tomasz; Stefan, Mihaela C


    Two new donor-acceptor small molecules based on benzo[1,2-b:4,5-b']dithiophene (BDT) and benzo[c][1,2,5]thiadiazole (BT) were designed and synthesized. Small molecules 4,4'-[(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl)bis(2,2'-bithiophene)-5,5'-diyl]bis(benzo[c][1,2,5]thiadiazole) (BDT-TT-BT) and 4,4'-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl)bis[7-(2,2'-bithiophene-5-yl)benzo[c][1,2,5]thiadiazole] (BDT-BT-TT) are structural isomers with the 2,2-bithiophene unit placed either between the BDT and BT units or at the end of the BT units. This work is targeted toward finding the effect of structural variation on optoelectronic properties, morphology, and photovoltaic performance. On the basis of theoretical calculations, the molecular geometry and energy levels are different for these two molecules when the position of the 2,2-bithiophene unit is changed. Optical and electrochemical properties of these two small molecules were characterized using UV-vis and cyclic voltammetry. The results showed that BDT-BT-TT has broader absorption and an elevated HOMO energy level when compared with those of BDT-TT-BT. The performance of these two isomers in solar cell devices was tested by blending with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM). Power conversion efficiencies as high as 3.22 and 3.71% were obtained in conventional solar cell structures for BDT-TT-BT and BDT-BT-TT, respectively. The morphology was studied using grazing incident wide-angle X-ray scattering and transmission electron microscopy, which revealed different phase separations of these two molecules when blended with PC71BM.

  8. Physical chemistry and membrane properties of two phosphatidylinositol bisphosphate isomers. (United States)

    Slochower, David R; Wang, Yu-Hsiu; Radhakrishnan, Ravi; Janmey, Paul A


    The most highly charged phospholipids, polyphosphoinositides, are often involved in signaling pathways that originate at cell-cell and cell-matrix contacts, and different isomers of polyphosphoinositides have distinct biological functions that cannot be explained by separate highly specific protein ligand binding sites [Lemmon, Nat. Rev. Mol. Cell Biol., 2008, 9, 99-111]. PtdIns(3,5)P2 is a low abundance phosphoinositide localized to cytoplasmic-facing membrane surfaces, with relatively few known ligands, yet PtdIns(3,5)P2 plays a key role in controlling membrane trafficking events and cellular stress responses that cannot be duplicated by other phosphoinositides [Dove et al., Nature, 1997, 390, 187-192; Michell, FEBS J., 2013, 280, 6281-6294]. Here we show that PtdIns(3,5)P2 is structurally distinct from PtdIns(4,5)P2 and other more common phospholipids, with unique physical chemistry. Using multiscale molecular dynamics techniques on the quantum level, single molecule, and in bilayer settings, we found that the negative charge of PtdIns(3,5)P2 is spread over a larger area, compared to PtdIns(4,5)P2, leading to a decreased ability to bind divalent ions. Additionally, our results match well with experimental data characterizing the cluster forming potential of these isomers in the presence of Ca(2+) [Wang et al., J. Am. Chem. Soc., 2012, 134, 3387-3395; van den Bogaart et al., Nature, 2011, 479, 552-555]. Our results demonstrate that the different cellular roles of PtdIns(4,5)P2 and PtdIns(3,5)P2in vivo are not simply determined by their localization by enzymes that produce or degrade them, but also by their molecular size, ability to chelate ions, and the partial dehydration of those ions, which might affect the ability of PtdIns(3,5)P2 and PtdIns(4,5)P2 to form phosphoinositide-rich clusters in vitro and in vivo.

  9. Isolation and spectral characterization of thermally generated multi-Z-isomers of lycopene and the theoretically preferred pathway to di-Z-isomers. (United States)

    Honda, Masaki; Kudo, Tatsuya; Kuwa, Takahiro; Higashiura, Takuma; Fukaya, Tetsuya; Inoue, Yoshinori; Kitamura, Chitoshi; Takehara, Munenori


    Lycopene has a large number of geometric isomers caused by E/Z isomerization at arbitrary sites within the 11 conjugated double bonds, offering varying characteristics related to features such as antioxidant capacity and bioavailability. However, the geometric structures of only a few lycopene Z-isomers have been thoroughly identified from natural sources. In this study, seven multi-Z-isomers of lycopene, (9Z,13'Z)-, (5Z,13Z,9'Z)-, (9Z,9'Z)-, (5Z,13'Z)-, (5Z,9'Z)-, (5Z,9Z,5'Z)-, and (5Z,9Z)-lycopene, were obtained from tomato samples by thermal isomerization, and then isolated by elaborate chromatography, and fully assigned using proton nuclear magnetic resonance. Moreover, the theoretically preferred pathway from (all-E)-lycopene to di-Z-isomers was examined with a computational approach using a Gaussian program. Fine-tuning of the HPLC separation conditions led to the discovery of novel multi-Z-isomers, and whose formation was supported by advanced theoretical calculations.

  10. Isomer Shift and Magnetic Moment of the Long-Lived 1/2^{+} Isomer in _{30}^{79}Zn_{49}: Signature of Shape Coexistence near ^{78}Ni. (United States)

    Yang, X F; Wraith, C; Xie, L; Babcock, C; Billowes, J; Bissell, M L; Blaum, K; Cheal, B; Flanagan, K T; Garcia Ruiz, R F; Gins, W; Gorges, C; Grob, L K; Heylen, H; Kaufmann, S; Kowalska, M; Kraemer, J; Malbrunot-Ettenauer, S; Neugart, R; Neyens, G; Nörtershäuser, W; Papuga, J; Sánchez, R; Yordanov, D T


    Collinear laser spectroscopy is performed on the _{30}^{79}Zn_{49} isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred milliseconds half-life is confirmed, and the nuclear spins and moments of the ground and isomeric states in ^{79}Zn as well as the isomer shift are measured. From the observed hyperfine structures, spins I=9/2 and I=1/2 are firmly assigned to the ground and isomeric states. The magnetic moment μ (^{79}Zn)=-1.1866(10)μ_{N}, confirms the spin-parity 9/2^{+} with a νg_{9/2}^{-1} shell-model configuration, in excellent agreement with the prediction from large scale shell-model theories. The magnetic moment μ (^{79m}Zn)=-1.0180(12)μ_{N} supports a positive parity for the isomer, with a wave function dominated by a 2h-1p neutron excitation across the N=50 shell gap. The large isomer shift reveals an increase of the intruder isomer mean square charge radius with respect to that of the ground state, δ⟨r_{c}^{2}⟩^{79,79m}=+0.204(6)  fm^{2}, providing first evidence of shape coexistence.

  11. Language as a coordination tool evolves slowly (United States)


    Social living ultimately depends on coordination between group members, and communication is necessary to make this possible. We suggest that this might have been the key selection pressure acting on the evolution of language in humans and use a behavioural coordination model to explore the impact of communication efficiency on social group coordination. We show that when language production is expensive but there is an individual benefit to the efficiency with which individuals coordinate their behaviour, the evolution of efficient communication is selected for. Contrary to some views of language evolution, the speed of evolution is necessarily slow because there is no advantage in some individuals evolving communication abilities that much exceed those of the community at large. However, once a threshold competence has been achieved, evolution of higher order language skills may indeed be precipitate. PMID:28083091

  12. Theoretical studies of possible toroidal high-spin isomers in the light-mass region

    CERN Document Server

    Staszczak, Andrzej


    We review our theoretical knowledge of possible toroidal high-spin isomers in the light mass region in 28$\\le$$A$$\\le$52 obtained previously in cranked Skyrme-Hartree-Fock calculations. We report additional toroidal high-spin isomers in $^{56}$Ni with $I$=114$\\hbar$ and 140$\\hbar$, which follow the same (multi-particle)--(multi-hole) systematics as other toroidal high-spin isomers. We examine the production of these exotic nuclei by fusion of various projectiles on $^{20}$Ne or $^{28}$Si as an active target in time-projection-chamber (TCP) experiments.

  13. Quantification of Triacylglycerol Positional Isomers in Rat Milk. (United States)

    Watanabe, Natsuko; Nagai, Toshiharu; Mizobe, Hoyo; Yoshinaga, Kazuaki; Yoshida, Akihiko; Kitamura, Yohei; Shimizu, Takashi; Beppu, Fumiaki; Gotoh, Naohiro


    The absolute amount of triacylglycerol (TAG) positional isomers was analyzed in rat milk fat, a representative of non-ruminant milk fat, using a HPLC-UV-atmospheric pressure chemical ionization-MS/MS system equipped with an octacosyl silylation column or polymeric ODS column. TAGs consisting of two oleic acids (O) and one palmitic acid (P) were the most abundant. In particular, β-OPO, a TAG binding P at the β-position (sn-2) and two Os at the α-positions (sn-1/3), was prominent. The β-OPO content decreased over time, while a TAG consisting of two Ps and one capric acid, a medium-chain fatty acid, increased. TAGs consisting of two Ps and one docosahexaenoic acid were present in small amounts and decreased with time. These results indicated that the recombination of fatty acids in TAGs in milk fat occurs in the mother, and is thought to depend on the infant's stage of growth, in response to their nutritional needs. It was also demonstrated that medium-chain fatty acids were mainly located at the α-position (sn-3), while Ps were mainly located at the β-position (sn-2). Therefore, the combination and binding positions of fatty acids of TAG are considered very important in infant nutrition.

  14. Interstellar Isomers: The Importance of Bonding Energy Differences

    CERN Document Server

    Remijan, A J; Lovas, F J; Plusquellic, D F; Jewell, P R; Remijan, Anthony J.


    We present strong detections of methyl cyanide, vinyl cyanide, ethyl cyanide and cyanodiacetylene molecules with the Green Bank Telescope (GBT) toward the Sgr B2(N) molecular cloud. Attempts to detect the corresponding isocyanide isomers were only successful in the case of methyl isocyanide for its J(K)=1(0)-0(0) transition, which is the first interstellar report of this line. To determine the spatial distribution of methyl isocyanide, we used archival Berkeley-Illinois-Maryland Association (BIMA) array data for the J(K)=4(K)-3(K) (K=0-3) transitions but no emission was detected. From ab initio calculations, the bonding energy difference between the cyanide and isocyanide molecules is >8500 cm^-1 (>12,000 K). That we detect methyl isocyanide emission with a single antenna (Gaussian beamsize(Omega_B)=1723 arcsec^2) but not with an interferometer (Omega_B=192 arcsec^2), strongly suggests that methyl isocyanide has a widespread spatial distribution toward the Sgr B2(N) region. Thus, large-scale, non-thermal proc...

  15. Isomers of fluoroamphetamines detected in forensic cases in Denmark

    DEFF Research Database (Denmark)

    Johansen, Sys Stybe; Hansen, Tina Maria


    A study was performed on the detection, separation and quantification of isomers from the new designer drugs named fluoroamphetamines (FAs) in forensic cases in eastern Denmark. The drugs were detected in whole blood extracts by ultraperformance liquid chromatography with time of flight mass...... by the retention time, multiple reaction monitoring (MRM) traces [154¿>¿109 (quantifier); 154¿>¿137], and ion ratio of the two transitions. For all FAs, LOQ was 0.002 mg/kg with linear ranges from 0.002 to 1.0 mg/kg whole blood. Since 2008, a total of 15 forensic investigations, mainly driving under the influence...... of drugs (DUID) cases, involving 4-fluoroamphetamine (4-FA) have been observed with whole blood concentrations ranging from 0.006 to 0.58 mg/kg. One autopsy case involved 4-FA; however, it was determined to be a combined intoxication. In 2010, ortho-fluoroamphetamine (2-FA) was discovered in forensic...

  16. Search for superradiant emission states in nuclear isomer crystals

    Energy Technology Data Exchange (ETDEWEB)

    Rundberg, R.S.; Wilhelmy, J.B.; Taylor, R.D.; Solem, J.C.; Fowler, M.M.; Miller, G.G.; Baldwin, G.


    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objective was to verify the stimulated emission of gamma rays from {sup 125m}Te, as claimed by Russian scientists. The reported cross section for stimulated emission was sufficiently large to allow gain in a single-pass gamma-ray laser. The stimulated emission of gamma rays from a nuclear isomer is expected to result in collinear photons and, therefore, should be observable as a sum peak in the gamma-ray spectrum. Skorobogatov and Dzevitskii reported an increase of an order of magnitude in the sum peak (218.56 keV) when a sample of beryllium telluride containing {sup 125m}Te was cooled from room temperature to near-liquid-helium temperatures. The authors have repeated their experiment and have observed no increase in the sum peak above accidental summing. The upper limit for the stimulated-emission cross section based on the three-standard-deviation statistical error is 6.8 x 10 {sup {minus}21} cm{sup 2}. This result is one order of magnitude lower than the cross section reported by Skorobogatov and Dzevitskii. The cross section would not allow gain in a single-pass gamma-ray laser. Their results support the position of Baldwin and Solem rather than that of Kamenov.

  17. Coordination models and languages

    NARCIS (Netherlands)

    Papadopoulos, G.A.; Arbab, F.


    A new class of models, formalisms and mechanisms has recently evolved for describing concurrent and distributed computations based on the concept of ``coordination''. The purpose of a coordination model and associated language is to provide a means of integrating a number of possibly heterogeneous c

  18. Team coordination dynamics. (United States)

    Gorman, Jamie C; Amazeen, Polemnia G; Cooke, Nancy J


    Team coordination consists of both the dynamics of team member interaction and the environmental dynamics to which a team is subjected. Focusing on dynamics, an approach is developed that contrasts with traditional aggregate-static concepts of team coordination as characterized by the shared mental model approach. A team coordination order parameter was developed to capture momentary fluctuations in coordination. Team coordination was observed in three-person uninhabited air vehicle teams across two experimental sessions. The dynamics of the order parameter were observed under changes of a team familiarity control parameter. Team members returned for the second session to either the same (Intact) or different (Mixed) team. 'Roadblock' perturbations, or novel changes in the task environment, were introduced in order to probe the stability of team coordination. Nonlinear dynamic methods revealed differences that a traditional approach did not: Intact and Mixed team coordination dynamics looked very different; Mixed teams were more stable than Intact teams and explored the space of solutions without the need for correction. Stability was positively correlated with the number of roadblock perturbations that were overcome successfully. The novel and non-intuitive contribution of a dynamical analysis was that Mixed teams, who did not have a long history working together, were more adaptive. Team coordination dynamics carries new implications for traditional problems such as training adaptive teams.

  19. Coordinate measuring machines

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    This document is used in connection with three exercises of 2 hours duration as a part of the course GEOMETRICAL METROLOGY AND MACHINE TESTING. The exercises concern three aspects of coordinate measuring: 1) Measuring and verification of tolerances on coordinate measuring machines, 2) Traceability...

  20. Social Postural Coordination (United States)

    Varlet, Manuel; Marin, Ludovic; Lagarde, Julien; Bardy, Benoit G.


    The goal of the current study was to investigate whether a visual coupling between two people can produce spontaneous interpersonal postural coordination and change their intrapersonal postural coordination involved in the control of stance. We examined the front-to-back head displacements of participants and the angular motion of their hip and…

  1. Social Postural Coordination (United States)

    Varlet, Manuel; Marin, Ludovic; Lagarde, Julien; Bardy, Benoit G.


    The goal of the current study was to investigate whether a visual coupling between two people can produce spontaneous interpersonal postural coordination and change their intrapersonal postural coordination involved in the control of stance. We examined the front-to-back head displacements of participants and the angular motion of their hip and…

  2. Ion mobility studies of carbohydrates as group I adducts: isomer specific collisional cross section dependence on metal ion radius. (United States)

    Huang, Yuting; Dodds, Eric D


    Carbohydrates play numerous critical roles in biological systems. Characterization of oligosaccharide structures is essential to a complete understanding of their functions in biological processes; nevertheless, their structural determination remains challenging in part due to isomerism. Ion mobility spectrometry provides the means to resolve gas phase ions on the basis of their shape-to-charge ratios, thus providing significant potential for separation and differentiation of carbohydrate isomers. Here, we report on the determination of collisional cross sections for four groups of isomeric carbohydrates (including five isomeric disaccharides, four isomeric trisaccharides, two isomeric pentasaccharides, and two isomeric hexasaccharides) as their group I metal ion adducts (i.e., [M + Li](+), [M + Na](+), [M + K](+), [M + Rb](+), and [M + Cs](+)). In all, 65 collisional cross sections were measured, the great majority of which have not been previously reported. As anticipated, the collisional cross sections of the carbohydrate metal ion adducts generally increase with increasing metal ion radius; however, the collisional cross sections were found to scale with the group I cation size in isomer specific manners. Such measurements are of substantial analytical value, as they illustrate how the selection of charge carrier influences carbohydrate ion mobility determinations. For example, certain pairs of isomeric carbohydrates assume unique collisional cross sections upon binding one metal ion, but not another. On the whole, these data suggest a role for the charge carrier as a probe of carbohydrate structure and thus have significant implications for the continued development and application of ion mobility spectrometry for the distinction and resolution of isomeric carbohydrates.

  3. Dynamic liquid phase nanoextraction coupled to GC/MS for rapid analysis of methoxyacetophenone and anisaldehyde isomers in urine. (United States)

    Wu, Hui-Fen; Yen, Jyh-Hao


    This study introduces a novel extraction technique in the nanoscale and challenges the limits of solvent extraction in the GC/MS using electronic ionization (EI) method for quantitative determination of six methoxyacetophenone (MAP) and anisaldehye (AAH) isomers in one drop of water and urine. This technique is termed as dynamic liquid phase nanoextraction (DLPNE). The optimum parameters for the DLPNE technique were: selection of solvent, toluene; sampling volume, 0.44 microL; dwell time, 2 s; number of sampling, 15; extraction time, 1.5 min; volume of extraction solvent, 60 nL; and no salt addition. The LODs for this technique were 5-20 ng/mL. The RSDs were in the range of 9.7-12.6% (n = 6). The linear dynamic range of the calibration curve of DLPNE is from 0.02 to 0.5 microg/mL with correlation coefficient (r(2)) >0.9705. The advantages of the DLPNE technique are rapidity, ease of operation, simple device, and extremely little solvent and sample consumption. This technique was also compared with the static liquid phase nanoextraction (SLPNE) while the SLPNE failed to detect any signal for the six isomers. We believe that this technique can be very useful for the detection of volatile organic compounds in environmental science from microscale of water or it can be applied to clinical or pharmaceutical application such as diagnosis of microamount of urine or blood samples by GC/MS.

  4. Optimal performance of single-column chromatography and simulated moving bed processes for the separation of optical isomers (United States)

    Medi, Bijan; Kazi, Monzure-Khoda; Amanullah, Mohammad


    Chromatography has been established as the method of choice for the separation and purification of optically pure drugs which has a market size of about 250 billion USD. Single column chromatography (SCC) is commonly used in the development and testing phase of drug development while multi-column Simulated Moving Bed (SMB) chromatography is more suitable for large scale production due to its continuous nature. In this study, optimal performance of SCC and SMB processes for the separation of optical isomers under linear and overloaded separation conditions has been investigated. The performance indicators, namely productivity and desorbent requirement have been compared under geometric similarity for the separation of a mixture of guaifenesin, and Tröger's base enantiomers. SCC process has been analyzed under equilibrium assumption i.e., assuming infinite column efficiency, and zero dispersion, and its optimal performance parameters are compared with the optimal prediction of an SMB process by triangle theory. Simulation results obtained using actual experimental data indicate that SCC may compete with SMB in terms of productivity depending on the molecules to be separated. Besides, insights into the process performances in terms of degree of freedom and relationship between the optimal operating point and solubility limit of the optical isomers have been ascertained. This investigation enables appropriate selection of single or multi-column chromatographic processes based on column packing properties and isotherm parameters.

  5. A Stable Coordination Complex of Rh(IV) in an N,O-Donor Environment. (United States)

    Sinha, Shashi B; Shopov, Dimitar Y; Sharninghausen, Liam S; Vinyard, David J; Mercado, Brandon Q; Brudvig, Gary W; Crabtree, Robert H


    We describe facial and meridional isomers of [Rh(III)(pyalk)3], as well as meridional [Rh(IV)(pyalk)3](+) {pyalk =2-(2-pyridyl)-2-propanoate}, the first coordination complex in an N,O-donor environment to show a clean, reversible Rh(III/IV) redox couple and to have a stable Rh(IV) form, which we characterize by EPR and UV-visible spectroscopy as well as X-ray crystallography. The unprecedented stability of the Rh(IV) species is ascribed to the exceptional donor strength of the ligands, their oxidation resistance, and the meridional coordination geometry.

  6. Disilicon complexes with two hexacoordinate Si atoms: paddlewheel-shaped isomers with (ClN4 )Si-Si(S4 Cl) and (ClN2 S2 )Si-Si(S2 N2 Cl) skeletons. (United States)

    Wagler, Jörg; Brendler, Erica; Heine, Thomas; Zhechkov, Lyuben


    The reaction of 1-methyl-3-trimethylsilylimidazoline-2-thione with hexachlorodisilane proceeds toward substitution of four of the disilane Cl atoms during the formation of disilicon complexes with two neighboring hexacoordinate Si atoms. The N,S-bidentate methimazolide moieties adopt a buttressing role, thus forming paddlewheel-shaped complexes of the type ClSi(μ-mt)4 SiCl (mt=methimazolyl). Most interestingly, three isomers (i.e., with (ClN4 )SiSi(S4 Cl), (ClN3 S)SiSi(S3 NCl), and (ClN2 S2 )SiSi(S2 N2 Cl) skeletons as so-called (4,0), (3,1), and cis-(2,2) paddlewheels) were detected in solution by using (29) Si NMR spectroscopic analysis. Two of these isomers could be isolated as crystalline solids, thus allowing their molecular structures to be analyzed by using X-ray diffraction studies. In accord with time-dependent NMR spectroscopy, computational analyses proved the cis-(2,2) isomer with a (ClN2 S2 )SiSi(S2 N2 Cl) skeleton to be the most stable. The compounds presented herein are the first examples of crystallographically evidenced disilicon complexes with two SiSi-bonded octahedrally coordinated Si atoms and representatives of the still scarcely explored class of Si coordination compounds with sulfur donor atoms.

  7. The Creation and Destruction of Hf-178m2 Isomer by Neutron Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Hsiao-Hua [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); TechSource, Inc. Los Alamos, NM (United States); Talbert, Willard L. [TechSource, Inc. Los Alamos, NM (United States); Ward, Tom [TechSource, Inc. Los Alamos, NM (United States)


    The property of the isomer state in 178m2Hf was an interesting topic in nuclear structure studies during the time period 1970 to 1980. The state at 2.446 MeV with spin and parity Kπ = 16+, has a half-life of 31 years. The isomer is described as a four-quasi-particle state. The K forbidden deexcitatiion by gamma emission is the reason for long half-life. During 1980, the isomer became a troublesome issue for radiation safety workers, because this isomer can also be produced in the first wall of a fussion reactor containing tungsten and also in a tungsten beam stop of a high-energy accelerator.

  8. Differential Effect of Amphetamine Optical Isomers on Bender Gestalt Performance of the Minimally Brain Dysfunctioned (United States)

    Arnold, L. Eugene; And Others


    The differential effect of amphetamine optical isomers on Bender Gestalt performance was examined in 31 hyperkinetic minimally brain dysfunctioned children between the ages of 4 and 12 years, using a double-blind Latin-square crossover comparison. (Author)

  9. Theoretical Studies on Structures and Stabilities of C4H2+ Isomers

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ying; WAN Su-qin; LIU Hui-ling; HUANG Xu-ri; SUN Chia-chung


    The structures,energies,stabilities and spectroscopies of doublet C4H2+ cations were explored at the DFT/B3LYP/6-311G(d,p),CCSD(T)/6-311+G(2df,2pd)(single-point),and G3B3 levels.Ten minimum isomers including the chainlike,three-member-ring,and four-member-ring structures are interconverted by means of 15 interconversion transition states.The potential energy surface was investigated.At the CCSD(T)/6-311+G(2df,2pd) and G3B3 levels,the global minimum isomer was found to be a linear HCCCCH.The structures of the stable isomer and its relevant transition state are further optimized at the QCISD/6-311G(d,p) level.The bonding nature and structure of isomer HCCCCH were analyzed.

  10. Study on Separation of Structural Isomer with Magneto-Archimedes method (United States)

    Kobayashi, T.; Mori, T.; Akiyama, Y.; Mishima, F.; Nishijima, S.


    Organic compounds are refined by separating their structural isomers, however each separation method has some problems. For example, distillation consumes large energy. In order to solve these problems, new separation method is needed. Considering organic compounds are diamagnetic, we focused on magneto-Archimedes method. With this method, particle mixture dispersed in a paramagnetic medium can be separated in a magnetic field due to the difference of the density and magnetic susceptibility of the particles. In this study, we succeeded in separating isomers of phthalic acid as an example of structural isomer using MnCl2 solution as the paramagnetic medium. In order to use magneto-Archimedes method for separating materials for food or medicine, we proposed harmless medium using oxygen and fluorocarbon instead of MnCl2 aqueous solution. As a result, the possibility of separating every structural isomer was shown.

  11. Toroidal high-spin isomers in light nuclei with N not equal to Z

    CERN Document Server

    Staszczak, Andrzej


    The combined considerations of both the bulk liquid-drop-type behavior and the quantized aligned rotation with cranked Skyrme-Hartree-Fock approach revealed previously that even-even, N=Z, toroidal high-spin isomeric states have general occurrences for light nuclei with A between 28 and 52. We find that in this mass region there are in addition N not equal to Z toroidal high-spin isomers when the single-particle shells for neutrons and protons occur at the same cranked frequency $\\hbar \\omega$. Examples of N not equal to Z toroidal high-spin isomers, $^{36}_{16}$S$_{20}$($I$=74$\\hbar$) and $^{40}_{18}$Ar$_{22}$($I$=80,102$\\hbar$), are located and examined. The systematic properties of these N not equal to Z toroidal high-spin isomers fall into the same regular (muti-particle)-(muti-hole) patterns as other N=Z toroidal high-spin isomers.

  12. Synthesis of an isomer of dihydrocolensenone; Sintesis parcial de un isomero de la dihidrocolensenona

    Energy Technology Data Exchange (ETDEWEB)

    Fraga, B.M.; Hernandez, M.G.; Luis, J.G. [Instituto de Productos naturales y Agrobiologia CSIC, Universidad de La Laguna, Tenerife (Spain)


    Starting from the diterpene ribenone, a isomer of dihydrocolensenone has been prepared. Its structure was different of dihydrotiganone, showing that the structure previously assigned to tiganone was erroneous. 13 refs.

  13. Isomer shift and magnetic moment of the long-lived 1/2$^{+}$ isomer in $^{79}_{30}$Zn$_{49}$: signature of shape coexistence near $^{78}$Ni

    CERN Document Server

    Yang, X.F.; Xie, L.; Babcock, C.; Billowes, J.; Bissell, M.L.; Blaum, K.; Cheal, B.; Flanagan, K.T.; Garcia Ruiz, R. F.; Gins, W.; Gorges, C.; Grob, L.K.; Heylen, H.; Kaufmann, S.; Kowalska, M.; Kraemer, J.; Malbrunot-Ettenauer, S.; Neugart, R.; Neyens, G.; Nörtershäuser, W.; Papuga, J.; Sánchez, R.; Yordanov, D.T.


    Collinear laser spectroscopy has been performed on the $^{79}_{30}$Zn$_{49}$ isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred milliseconds half-life was confirmed, and the nuclear spins and moments of the ground and isomeric states in $^{79}$Zn as well as the isomer shift were measured. From the observed hyperfine structures, spins $I = 9/2$ and $I = 1/2$ are firmly assigned to the ground and isomeric states. The magnetic moment $\\mu$ ($^{79}$Zn) = $-$1.1866(10) $\\mu_{\\rm{N}}$, confirms the spin-parity $9/2^{+}$ with a $\

  14. Yeast contribution to melatonin, melatonin isomers and tryptophan ethyl ester during alcoholic fermentation of grape musts. (United States)

    Vigentini, Ileana; Gardana, Claudio; Fracassetti, Daniela; Gabrielli, Mario; Foschino, Roberto; Simonetti, Paolo; Tirelli, Antonio; Iriti, Marcello


    Melatonin (MEL) has been found in some medicinal and food plants, including grapevine, a commodity of particular interest for the production of wine, a beverage of economic relevance. It has also been suggested that MEL in wine may, at least in part, contribute to the health-promoting properties attributed to this beverage and, possibly, to other traditional Mediterranean foodstuffs. After a preliminary screening of 9 yeast strains in laboratory medium, three selected strains (Saccharomyces cerevisiae EC1118, Torulaspora delbrueckii CBS1146(T) and Zygosaccharomyces bailii ATCC36947(T) ) were inoculated in experimental musts obtained from 2 white (Moscato and Chardonnay) and 2 red (Croatina and Merlot) grape varieties. The production of MEL, melatonin isomers (MIs) and tryptophan ethyl ester (TEE) was monitored during the alcoholic fermentation. The screening showed that the three investigated strains produced the highest concentrations of MEL and two MIs in optimal growth conditions. However, MEL and MIs were not produced in oenological conditions, but the three strains synthesized high concentrations of a new MI and TEE in musts.

  15. Structural, Electronic, and Vibrational Properties of Amino-adamantane and Rimantadine Isomers

    CERN Document Server

    Garcia, Joelson Cott; Machado, Wanda V M; Assali, Lucy V C; 10.1021/jp107496b


    We performed a first principles total energy investigation on the structural, electronic, and vibrational properties of adamantane molecules, functionalized with amine and ethanamine groups. We computed the vibrational signatures of amantadine and rimantadine isomers with the functional groups bonded to different carbon sites. By comparing our results with recent infrared and Raman spectroscopic data, we discuss the possible presence of different isomers in experimental samples.

  16. Discovery of a 7.6-hour high-spin isomer of einsteinium-256

    CERN Document Server

    Lougheed, R W; Daniels, W R; Hoffman, D C; Jackson, S V; Landrum, J H; Starner, J W; Wilhelmy, J B


    A 7.6-hour, beta-emitting isomer of /sup 256/Es has been produced via the (t, p) reaction by bombarding /sup 254g/Es with 16-MeV tritons. No evidence for an alpha branch has been found. A number of gamma rays have been observed, on the basis of which a partial decay scheme is proposed. It is concluded that the isomer has spin 7 or 8. (2 refs).

  17. Theoretical investigation of thermodynamic balance between cluster isomers and statistical model for predicting isomerization rate

    CERN Document Server

    Lin, Zheng-Zhe


    By molecular dynamics simulations and free energy calculations based on Monte Carlo method, the detailed balance between Pt cluster isomers was investigated. For clusters of n50. Then, a statistical mechanical model was built to evaluate unimolecular isomerization rate and simplify the prediction of isomer formation probability. This model is simpler than transition state theory and can be easily applied on ab initio calculations to predict the lifetime of nanostructures.

  18. The sim Operon Facilitates the Transport and Metabolism of Sucrose Isomers in Lactobacillus casei ATCC 334



    Inspection of the genome sequence of Lactobacillus casei ATCC 334 revealed two operons that might dissimilate the five isomers of sucrose. To test this hypothesis, cells of L. casei ATCC 334 were grown in a defined medium supplemented with various sugars, including each of the five isomeric disaccharides. Extracts prepared from cells grown on the sucrose isomers contained high levels of two polypeptides with Mrs of ~50,000 and ~17,500. Neither protein was present in cells grown on glucose, ma...

  19. Optimized coordinates for anharmonic vibrational structure theories. (United States)

    Yagi, Kiyoshi; Keçeli, Murat; Hirata, So


    A procedure to determine optimal vibrational coordinates is developed on the basis of an earlier idea of Thompson and Truhlar [J. Chem. Phys. 77, 3031 (1982)]. For a given molecule, these coordinates are defined as the unitary transform of the normal coordinates that minimizes the energy of the vibrational self-consistent-field (VSCF) method for the ground state. They are justified by the fact that VSCF in these coordinates becomes exact in two limiting cases: harmonic oscillators, where the optimized coordinates are normal, and noninteracting anharmonic oscillators, in which the optimized coordinates are localized on individual oscillators. A robust and general optimization algorithm is developed, which decomposes the transformation matrix into a product of Jacobi matrices, determines the rotation angle of each Jacobi matrix that minimizes the energy, and iterates the process until a minimum in the whole high dimension is reached. It is shown that the optimized coordinates are neither entirely localized nor entirely delocalized (or normal) in any of the molecules (the water, water dimer, and ethylene molecules) examined (apart from the aforementioned limiting cases). Rather, high-frequency stretching modes tend to be localized, whereas low-frequency skeletal vibrations remain normal. On the basis of these coordinates, we introduce two new vibrational structure methods: optimized-coordinate VSCF (oc-VSCF) and optimized-coordinate vibrational configuration interaction (oc-VCI). For the modes that become localized, oc-VSCF is found to outperform VSCF, whereas, for both classes of modes, oc-VCI exhibits much more rapid convergence than VCI with respect to the rank of excitations. We propose a rational configuration selection for oc-VCI when the optimized coordinates are localized. The use of the optimized coordinates in VCI with this configuration selection scheme reduces the mean absolute errors in the frequencies of the fundamentals and the first overtones

  20. On the Relative Stability of Cumulenone and Aldehyde Isomers: when we HEAT345(Q) Things UP (United States)

    Lee, Kelvin; McCarthy, Michael C.; Stanton, John F.


    Isomers of H_2C_{2n+1}O are examples of complex organic molecules that are either known or proposed to exist in the interstellar medium. For the smallest of these chains (H_2C_3O) only two of three isomers are observed in space: propynal (HC(O)CCH) and cyclopropenone (c-C_3H_2O), while evidence for the remaining isomer propadienone (H_2C_3O) is currently lacking. Potentially, this behaviour may be rationalised by a thermodynamic argument: several studies have provided quantum chemical calculations in an effort to determine the relative thermodynamic stability between these three isomers. An early study by Radom, at the SCF/6-31G** level ranked HC(O)CCH as the thermodynamic minimum, followed by H_2C_3O, and c-C_3H_2O. The most recent determination by Karton and Talbi, using W2-F12 theory, places H_2C_3O as the lowest energy isomer; 2.5 kJ mol^{-1} lower than the HC(O)CCH form. In an attempt to resolve this long-standing ambiguity, we were motivated to provide high level calculations based on the HEAT protocol. In this talk, we will discuss the relative stability of H_2C_3O and H_2C_5O isomers, along with their sulfur analogues, as revealed by HEAT345(Q) theory.

  1. Roles of the tyrosine isomers meta-tyrosine and ortho-tyrosine in oxidative stress. (United States)

    Ipson, Brett R; Fisher, Alfred L


    The damage to cellular components by reactive oxygen species, termed oxidative stress, both increases with age and likely contributes to age-related diseases including Alzheimer's disease, atherosclerosis, diabetes, and cataract formation. In the setting of oxidative stress, hydroxyl radicals can oxidize the benzyl ring of the amino acid phenylalanine, which then produces the abnormal tyrosine isomers meta-tyrosine or ortho-tyrosine. While elevations in m-tyrosine and o-tyrosine concentrations have been used as a biological marker of oxidative stress, there is emerging evidence from bacterial, plant, and mammalian studies demonstrating that these isomers, particularly m-tyrosine, directly produce adverse effects to cells and tissues. These new findings suggest that the abnormal tyrosine isomers could in fact represent mediators of the effects of oxidative stress. Consequently the accumulation of m- and o-tyrosine may disrupt cellular homeostasis and contribute to disease pathogenesis, and as result, effective defenses against oxidative stress can encompass not only the elimination of reactive oxygen species but also the metabolism and ultimately the removal of the abnormal tyrosine isomers from the cellular amino acid pool. Future research in this area is needed to clarify the biologic mechanisms by which the tyrosine isomers damage cells and disrupt the function of tissues and organs and to identify the metabolic pathways involved in removing the accumulated isomers after exposure to oxidative stress.

  2. Estrogen equivalent concentration of individual isomer-specific 4-nonylphenol in Ariake sea water, Japan. (United States)

    Kim, Yun-Seok; Katase, Takao; Horii, Yuichi; Yamashita, Nobuyoshi; Makino, Mitsuko; Uchiyama, Taketo; Fujimoto, Yasuo; Inoue, Tadashi


    Concentrations of 4-nonylphenol (NP) were determined by isomer-specific quantification of individual NP isomers based on relative response factor (RRF) quantification with GC-MS in combination with steam distillation extraction. Concentrations of NP in the Ariake Sea decreased with distance from the river mouth (St.A; 49 ng NP/l) to offshore areas (St.C; 11 ng NP/l). Even the least concentration in water from St.C in Ariake Sea was sufficient to have adverse effects on barnacles. The isomers, NP1-NP14 were separated by GC-PFC and identified structurally with NMR. The isomers varied in estrogenic activity with NP7 exhibiting the greatest estrogenic activity with a potency that was approximately 1.9 x 10(-3) that of 17beta-estradiol (E2) in recombinant yeast screen system. The coefficient of variation (CV) of NP isomer's concentrations among three samples at St.A, B and C were 4-75%. This suggests that NP isomers might be independently degraded in aquatic environmental samples. The predicted estrogenic activity of measured concentrations of NP in Ariake Sea was 2.7-3.0-fold greater than the measured estrogen agonist activity.

  3. Surfactant mediated enhanced biodegradation of hexachlorocyclohexane (HCH) isomers by Sphingomonas sp. NM05. (United States)

    Manickam, Natesan; Bajaj, Abhay; Saini, Harvinder S; Shanker, Rishi


    Environmental biodegradation of several chlorinated pesticides is limited by their low solubility and sorption to soil surfaces. To mitigate this problem we quantified the effect of three biosurfactant viz., rhamnolipid, sophorolipid and trehalose-containing lipid on the dissolution, bioavailability, and biodegradation of HCH-isomers in liquid culture and in contaminated soil. The effect of biosurfactants was evaluated through the critical micelle concentration (CMC) value as determined for each isomer. The surfactant increased the solubilization of HCH isomers by 3-9 folds with rhamnolipid and sophorolipid being more effective and showing maximum solubilization of HCH isomers at 40 μg/mL, compared to trehalose-containing lipid showing peak solubilization at 60 μg/mL. The degradation of HCH isomers by Sphingomonas sp. NM05 in surfactant-amended liquid mineral salts medium showed 30% enhancement in 2 days as compared to degradation in 10 days in the absence of surfactant. HCH-spiked soil slurry incubated with surfactant also showed around 30-50% enhanced degradation of HCH which was comparable to the corresponding batch culture experiments. Among the three surfactants, sophorolipid offered highest solubilization and enhanced degradation of HCH isomers both in liquid medium and soil culture. The results of this study suggest the effectiveness of surfactants in improving HCH degradation by increased bioaccessibility.

  4. 241Am (n,gamma) isomer ratio measurement

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Evelyn M [Los Alamos National Laboratory; Vieira, David J [Los Alamos National Laboratory; Moody, Walter A [Los Alamos National Laboratory; Slemmons, Alice K [Los Alamos National Laboratory


    The objective of this project is to improve the accuracy of the {sup 242}Cm/{sup 241}Am radiochemistry ratio. We have performed an activation experiment to measure the {sup 241}Am(n,{gamma}) cross section leading to either the ground state of {sup 242g}Am (t{sub 1/2} = 16 hr) which decays to {sup 242}Cm (t{sub 1/2} = 163 d) or the long-lived isomer {sup 242m}Am (t{sub 1/2} = 141 yr). This experiment will develop a new set of americium cross section evaluations that can be used with a measured {sup 242}Cm/{sup 241}Am radiochemical measurement for nuclear forensic purposes. This measurement is necessary to interpret the {sup 242}Cm/{sup 241}Am ratio because a good measurement of this neutron capture isomer ratio for {sup 241}Am does not exist. The targets were prepared in 2007 from {sup 241}Am purified from LANL stocks. Gold was added to the purified {sup 241}Am as an internal neutron fluence monitor. These targets were placed into a holder, packaged, and shipped to Forschungszentrum Karlsruhe, where they were irradiated at their Van de Graff facility in February 2008. One target was irradiated with {approx}25 keV quasimonoenergetic neutrons produced by the {sup 7}Li(p,n) reaction for 3 days and a second target was also irradiated for 3 days with {approx}500 keV neutrons. Because it will be necessary to separate the {sup 242}Cm from the {sup 241}Am in order to measure the amount of {sup 242}Cm by alpha spectrometry, research into methods for americium/curium separations were conducted concurrently. We found that anion exchange chromatography in methanol/nitric acid solutions produced good separations that could be completed in one day resulting in a sample with no residue. The samples were returned from Germany in July 2009 and were counted by gamma spectrometry. Chemical separations have commenced on the blank sample. Each sample will be spiked with {sup 244}Cm, dissolved and digested in nitric acid solutions. One third of each sample will be processed at a time

  5. Uranyl ion coordination (United States)

    Evans, H.T.


    A review of the known crystal structures containing the uranyl ion shows that plane-pentagon coordination is equally as prevalent as plane-square or plane-hexagon. It is suggested that puckered-hexagon configurations of OH - or H2O about the uranyl group will tend to revert to plane-pentagon coordination. The concept of pentagonal coordination is invoked for possible explanations of the complex crystallography of the natural uranyl hydroxides and the unusual behavior of polynuclear ions in hydrolyzed uranyl solutions.

  6. In Vivo Differences between Two Optical Isomers of Radioiodinated o-iodo-trans-decalinvesamicol for Use as a Radioligand for the Vesicular Acetylcholine Transporter.

    Directory of Open Access Journals (Sweden)

    Izumi Uno

    Full Text Available To develop a superior VAChT imaging probe for SPECT, radiolabeled (--OIDV and (+-OIDV were isolated and investigated for differences in their binding affinity and selectivity to VAChT, as well as their in vivo activities.Radioiodinated o-iodo-trans-decalinvesamicol ([125I]OIDV has a high binding affinity for vesicular acetylcholine transporter (VAChT both in vitro and in vivo. Racemic [125I]OIDV was separated into its two optical isomers (--[125I]OIDV and (+-[125I]OIDV by HPLC. To investigate VAChT binding affinity (Ki of two OIDV isomers, in vitro binding assays were performed. In vivo biodistribution study of each [125I]OIDV isomer in blood, brain regions and major organs of rats was performed at 2,30 and 60 min post-injection. In vivo blocking study were performed to reveal the binding selectivity of two [125I]OIDV isomers to VAChT in vivo. Ex vivo autoradiography were performed to reveal the regional brain distribution of two [125I]OIDV isomers and (--[123I]OIDV for SPECT at 60 min postinjection.VAChT binding affinity (Ki of (--[125I]OIDV and (+-[125I]OIDV was 22.1 nM and 79.0 nM, respectively. At 2 min post-injection, accumulation of (--[125I]OIDV was the same as that of (+-[125I]OIDV. However, (+-[125I]OIDV clearance from the brain was faster than (--[125I]OIDV. At 30 min post-injection, accumulation of (--[125I]OIDV (0.62 ± 0.10%ID/g was higher than (+-[125I]OIDV (0.46 ± 0.07%ID/g in the cortex. Inhibition of OIDV binding showed that (--[125I]OIDV was selectively accumulated in regions known to express VAChT in the rat brain, and ex vivo autoradiography further confirmed these results showing similar accumulation of (--[125I]OIDV in these regions. Furthermore, (--[123I]OIDV for SPECT showed the same regional brain distribution as (--[125I]OIDV.These results suggest that radioiodinated (--OIDV may be a potentially useful tool for studying presynaptic cholinergic neurons in the brain.

  7. Vibronic Spectroscopy of a Structural Isomer of Quinoline: - (United States)

    Mehta-Hurt, Deepali N.; Korn, Joseph A.; Zwier, Timothy S.


    This talk will present results of a gas phase, jet-cooled vibronic spectroscopy study of (Z)-phenylvinylnitrile ((Z)-C_6H_5-CH=CH-C=N, (Z)-PVN). With a substituent locked into a cis conformation with respect to the aromatic ring, (Z)-PVN is postulated to be a molecule with an ideal functionality to isomerize to quinoline upon photoexcitation. As such, (Z)-PVN is particularly relevant to Titan's nitrile-containing atmosphere, where much of the chemistry is photochemically driven. As a first step towards such photochemical studies, a fluorescence excitation spectrum of a mixture of (E)- and (Z)-PVN was collected spanning the range 33,300-35,580 cm^{-1} (300.0-281.0 nm). Previous investigations in the Zwier group pertaining to the vibronic spectroscopy of (E)-PVN allowed for the identification of peaks in the (E)- and (Z)-PVN composite spectrum that were solely due to (Z)-PVN, and the S_0-S_1 origin of (Z)-PVN was identified as a dominant band that occurs at 33,706 cm^{-1}. For additional confirmation, ultraviolet depletion spectroscopy (UVD) was used to obtain an isomer specific spectrum of (Z)-PVN as well as search for non-radiative transitions. Dispersed fluorescence spectra that characterize the vibronic activity have also been acquired. A comparison between the vibronic spectroscopy of (Z)-PVN with both (E)-PVN and (Z)-phenylvinylacetylene ((Z)-PVA), the hydrocarbon analog of (Z)-PVN, will be made in this talk.

  8. Isomer separation of {sup 70g}Cu and {sup 70m}Cu with a resonance ionization laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Koester, U. E-mail:; Fedoseyev, V.N.; Mishin, V.I.; Weissman, L.; Huyse, M.; Kruglov, K.; Mueller, W.F.; Duppen, P. van; Roosbroeck, J. van; Thirolf, P.; Thomas, H.G.; Weisshaar, D.; Schulze, W.; Borcea, R.; La Commara, M.; Schatz, H.; Schmidt, K.; Roettger, S.; Huber, G.; Sebastian, V.; Kratz, K.L.; Catherall, R.; Georg, U.; Lettry, J.; Oinonen, M.; Ravn, H.L.; Simon, H


    Radioactive copper isotopes were ionized with the resonance ionization laser ion source (RILIS) at the on-line isotope separator ISOLDE (CERN). Using the different hyperfine structure in the 3d{sup 10} 4s {sup 2}S{sub 1/2} - 3d{sup 10} 4p {sup 2}P{sup 0}{sub 1/2} transition the low- and high-spin isomers of {sup 70}Cu were selectively enhanced by tuning the laser wavelength. The light was provided by a narrow-bandwidth dye laser pumped by copper vapor lasers (CVL) and frequency doubled in a BBO crystal. The ground state to isomeric state intensity ratio could be varied by a factor of 30, allowing to assign gamma transitions unambiguously to the decay of the individual isomers. It is shown that the method can also be used to determine magnetic moments. In a first experiment for the 1{sup +} ground state of {sup 70}Cu a magnetic moment of (+)1.8(3) {mu}{sub N} and for the high-spin isomer of {sup 70}Cu a magnetic moment of ({+-})1.2(3) {mu}{sub N} could be deduced.

  9. Magnetic Coordinate Systems

    CERN Document Server

    Laundal, K M


    Geospace phenomena such as the aurora, plasma motion, ionospheric currents and associated magnetic field disturbances are highly organized by Earth's main magnetic field. This is due to the fact that the charged particles that comprise space plasma can move almost freely along magnetic field lines, but not across them. For this reason it is sensible to present such phenomena relative to Earth's magnetic field. A large variety of magnetic coordinate systems exist, designed for different purposes and regions, ranging from the magnetopause to the ionosphere. In this paper we review the most common magnetic coordinate systems and describe how they are defined, where they are used, and how to convert between them. The definitions are presented based on the spherical harmonic expansion coefficients of the International Geomagnetic Reference Field (IGRF) and, in some of the coordinate systems, the position of the Sun which we show how to calculate from the time and date. The most detailed coordinate systems take the...

  10. Supercritical Airfoil Coordinates (United States)

    National Aeronautics and Space Administration — Rectangular Supercritical Wing (Ricketts) - design and measured locations are provided in an Excel file RSW_airfoil_coordinates_ricketts.xls . One sheet is with Non...

  11. Understanding social motor coordination. (United States)

    Schmidt, R C; Fitzpatrick, Paula; Caron, Robert; Mergeche, Joanna


    Recently there has been much interest in social coordination of motor movements, or as it is referred to by some researchers, joint action. This paper reviews the cognitive perspective's common coding/mirror neuron theory of joint action, describes some of its limitations and then presents the behavioral dynamics perspective as an alternative way of understanding social motor coordination. In particular, behavioral dynamics' ability to explain the temporal coordination of interacting individuals is detailed. Two experiments are then described that demonstrate how dynamical processes of synchronization are apparent in the coordination underlying everyday joint actions such as martial art exercises, hand-clapping games, and conversations. The import of this evidence is that emergent dynamic patterns such as synchronization are the behavioral order that any neural substrate supporting joint action (e.g., mirror systems) would have to sustain.

  12. Environmental Compliance Issue Coordination (United States)

    An order to establish the Department of Energy (DOE) requirements for coordination of significant environmental compliance issues to ensure timely development and consistent application of Departmental environmental policy and guidance

  13. Definition of "positional isomer" as it pertains to the control of schedule I controlled substances. Final rule. (United States)


    On May 25, 2006, DEA published a Notice of Proposed Rulemaking which proposed the addition of a specific definition for the term "positional isomer" to allow for the systematic determination of which isomers of schedule I substances would be considered to be "positional," and therefore, subject to schedule I control. This rulemaking finalizes that definition. The Controlled Substances Act (CSA) and its implementing regulations specify which hallucinogenic substances are considered schedule I controlled substances. The CSA states that all salts, isomers, and salts of isomers of these substances are also schedule I controlled substances. In non-technical terms, an isomer of a substance is a different compound, but a compound which has the same number and kind of atoms. The terms "optical isomer" and "geometric isomer" are specific scientific terms and it is easy to determine whether one substance is an optical or geometric isomer of another. The term "positional isomer," however, is subject to scientific interpretation. The addition of a definition for the term "positional isomer" will assist legitimate research[ers] and industry in determining the control status of materials that are "positional isomers" of schedule I hallucinogens. While the DEA will remain the authority for ultimately determining the control status of a given material, providing a specific definition for "positional isomer" will ensure consistent criteria are utilized in making these determinations. This rule does not change existing laws, regulations, policies, processes, and procedures regarding the determination of control status for schedule I hallucinogenic substances. This rule merely makes available to the public the longstanding definition of "positional isomer" which DEA has used when making these scheduling determinations. This rule is relevant only to specialized forensic or research chemists. Most of these individuals are existing DEA registrants who are authorized by the DEA to handle

  14. Mass spectrometry based identification of geometric isomers during metabolic stability study of a new cytotoxic sulfonamide derivatives supported by quantitative structure-retention relationships.

    Directory of Open Access Journals (Sweden)

    Mariusz Belka

    Full Text Available A set of 15 new sulphonamide derivatives, presenting antitumor activity have been subjected to a metabolic stability study. The results showed that besides products of biotransformation, some additional peaks occurred in chromatograms. Tandem mass spectrometry revealed the same mass and fragmentation pathway, suggesting that geometric isomerization occurred. Thus, to support this hypothesis, quantitative structure-retention relationships were applied. Human liver microsomes were used as an in vitro model of metabolism. The biotransformation reactions were tracked by liquid chromatography assay and additionally, fragmentation mass spectra were recorded. In silico molecular modeling at a semi-empirical level was conducted as a starting point for molecular descriptor calculations. A quantitative structure-retention relationship model was built applying multiple linear regression based on selected three-dimensional descriptors. The studied compounds revealed high metabolic stability, with a tendency to form hydroxylated biotransformation products. However, significant chemical instability in conditions simulating human body fluids was noticed. According to literature and MS data geometrical isomerization was suggested. The developed in sillico model was able to describe the relationship between the geometry of isomer pairs and their chromatographic retention properties, thus it supported the hypothesis that the observed pairs of peaks are most likely geometric isomers. However, extensive structural investigations are needed to fully identify isomers' geometry. An effort to describe MS fragmentation pathways of novel chemical structures is often not enough to propose structures of potent metabolites and products of other chemical reactions that can be observed in compound solutions at early drug discovery studies. The results indicate that the relatively non-expensive and not time- and labor-consuming in sillico approach could be a good supportive

  15. [Coordination and donation]. (United States)

    Elizalde, J; Lorente, M


    The progressive incorporation of organ transplants as a therapeutic resource resulted in organisational adaptation and overall transplant management, leading to the emergence of the figure of the transplant coordinator in the mid-1980s. In Spain, the National Organisation of Transplants (Organización Nacional de Transplantes - ONT) was created, establishing a system - called the "Spanish model" - based on a network of coordinators at three levels: national, the autonomous community and the hospital. This organisational structure is a point of reference at the world level. The prevalence of the Intensive Medicine specialisation amongst hospital transplant coordinators is remarkable. The majority of organs proceed from brain-dead patients with beating hearts and this requires the infrastructure offered by intensive care units. The functions of the coordinator can be summarised in guaranteeing a synchrony of all the elements and teams that come together in an organisational chain that has come to be called the "process of donation". Schematically, the crucial points that the hospital coordinator develops are the following: - Detection of the potential donor. - Maintenance of the donor. - Diagnosis of brain death. - Family consent. - Preparation of the hospital logistics. - Helping the relatives. - Direct involvement in the Program of Guarantee of Quality. - Person of reference in any activity related to the transplant. It would be desirable to achieve the creation of transplant coordination teams, with univocal messages, professionalism and a permanent input of the so-called "human factor", which is so necessary and also so close to the transplant world.

  16. Continuous parallel coordinates. (United States)

    Heinrich, Julian; Weiskopf, Daniel


    Typical scientific data is represented on a grid with appropriate interpolation or approximation schemes,defined on a continuous domain. The visualization of such data in parallel coordinates may reveal patterns latently contained in the data and thus can improve the understanding of multidimensional relations. In this paper, we adopt the concept of continuous scatterplots for the visualization of spatially continuous input data to derive a density model for parallel coordinates. Based on the point-line duality between scatterplots and parallel coordinates, we propose a mathematical model that maps density from a continuous scatterplot to parallel coordinates and present different algorithms for both numerical and analytical computation of the resulting density field. In addition, we show how the 2-D model can be used to successively construct continuous parallel coordinates with an arbitrary number of dimensions. Since continuous parallel coordinates interpolate data values within grid cells, a scalable and dense visualization is achieved, which will be demonstrated for typical multi-variate scientific data.

  17. Magnetic Coordinate Systems (United States)

    Laundal, K. M.; Richmond, A. D.


    Geospace phenomena such as the aurora, plasma motion, ionospheric currents and associated magnetic field disturbances are highly organized by Earth's main magnetic field. This is due to the fact that the charged particles that comprise space plasma can move almost freely along magnetic field lines, but not across them. For this reason it is sensible to present such phenomena relative to Earth's magnetic field. A large variety of magnetic coordinate systems exist, designed for different purposes and regions, ranging from the magnetopause to the ionosphere. In this paper we review the most common magnetic coordinate systems and describe how they are defined, where they are used, and how to convert between them. The definitions are presented based on the spherical harmonic expansion coefficients of the International Geomagnetic Reference Field (IGRF) and, in some of the coordinate systems, the position of the Sun which we show how to calculate from the time and date. The most detailed coordinate systems take the full IGRF into account and define magnetic latitude and longitude such that they are constant along field lines. These coordinate systems, which are useful at ionospheric altitudes, are non-orthogonal. We show how to handle vectors and vector calculus in such coordinates, and discuss how systematic errors may appear if this is not done correctly.

  18. Sonochemical Synthesis of UiO-66 for CO{sub 2} Adsorption and Xylene Isomer Separation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hee-Young; Kim, Se-Na; Kim, Jun; Ahn, Wha-Seung [Inha University, Incheon (Korea, Republic of)


    Zr-benzendicarboxylate structure, UiO-66 was prepared in 1-L batch scale by using a unique sonochemical-solvothermal combined synthesis method. The produced UiO-66 showed uniform particles of ca. 0.2 µm in size with the BET surface area of 1,375 m{sup 2}/g in high product yield (>95%). The UiO-66 showed 198 and 84 mg/g CO{sub 2} adsorption capacity at 273 K and 298 K, respectively, with excellent CO{sub 2} selectivity (CO{sub 2}:N{sub 2}=32:1) at ambient conditions. The isosteric heat of CO{sub 2} adsorption varied from 33 to 25 kJ/mol as the adsorption progressed. The UiO-66 tested for xylene isomer separation in a liquid-phase batch mode confirmed preferential adsorption of the adsorbent for o-xylene over m-, and p-xylene.

  19. A 2:1 cocrystal of the cis and trans isomers of bis-[1,1,1,5,5,5-hexa-fluoro-pentane-2,4-dionato(1-)-κO,O']bis-(4-phenyl-pyridine N-oxide-κO)copper(II). (United States)

    Fernandes, José A; Ramos, Ana I; Braga, Susana S; Almeida Paz, Filipe A


    The title compound is a co-crystal of the cis and trans isomers, namely cis-bis-[1,1,1,5,5,5-hexa-fluoro-pentane-2,4-dionato(1-)-κ(2)O,O']bis-(4-phenyl-pyridine N-oxide-κO)copper(II)-trans-bis-[1,1,1,5,5,5-hexa-fluoro-pentane-2,4-dionato(1-)-κ(2)O,O']bis(4-phenyl-pyridine N-oxide-κO)copper(II) (2/1), [Cu(C(5)HF(6)O(2))(2)(C(11)H(9)NO)(2)]. In both isomers, the coordination geometry of the Cu(2+) atom is octa-hedral, exhibiting typical Jahn-Teller distortion. The metal atom of the trans isomer is located on an inversion centre. In the cis isomer, the phenyl ring in one 4-phenyl-pyridine N-oxide ligand is disordered over two orientations in a 1:1 ratio. In the crystal, weak inter-molecular C-H⋯F and C-H⋯O contacts establish connections between the cis and trans isomers.

  20. Maternal dietary Alpine butter intake affects human milk: fatty acids and conjugated linoleic acid isomers. (United States)

    Bertschi, Isabelle; Collomb, Marius; Rist, Lukas; Eberhard, Pius; Sieber, Robert; Bütikofer, Ulrich; Wechsler, Daniel; Folkers, Gerd; von Mandach, Ursula


    Consumption of CLA by lactating women affects the composition of their milk, but the pattern of the different CLA isomers is still unknown. We determined the effects of short maternal supplementation with CLA-rich Alpine butter on the occurrence of FA and CLA isomers in human milk. In an open randomized controlled study with a two-period cross-over design, milk FA and CLA isomer concentrations were measured on postpartum days > or = 20 in two parallel groups of lactating women before, during, and after consumption of defined quantities of Alpine butter or margarine with comparable fat content (10 d of butter followed by 10 d of margarine for one group, and vice versa in the other). In the 16 women who completed the study (8/group), Alpine butter supplementation increased the C16 and C18 FA, the sum of saturated FA, the 18:1 trans FA, and the trans FA with CLA. The CLA isomer 18:2 c9,t11 increased by 49.7%. Significant increases were also found for the isomers t9,t11, t7,c9, t11,c13, and t8,c10 18:2. The remaining nine of the total 14 detectable isomers showed no changes, and concentrations were <5 mg/100 g fat. A breastfeeding mother can therefore modulate the FA/CLA supply of her child by consuming Alpine butter. Further studies will show whether human milk containing this FA and CLA isomer pattern acts as a functional food for newborns.

  1. A Highly Stable Nanotubular MOF Rotator for Selective Adsorption of Benzene and Separation of Xylene Isomers. (United States)

    Huang, Wei; Jiang, Jun; Wu, Dayu; Xu, Jun; Xue, Bing; Kirillov, Alexander M


    A remarkably stable tubular 3D Zn-MOF with hexagonal channels and a rare ptr topology was prepared under solvothermal conditions for liquid and vapor phase adsorption and separation of the C6-8 aromatic compounds. The material showed preferential affinity for benzene and can effectively separate benzene from its organic analogues under ambient conditions in both vapor and liquid phases. Furthermore, it exhibited preferable uptake of p-xylene over other C8 xylenes.

  2. Great Lakes Contaminant Impacts Study: Residue analysis report on selected PCB Isomers in common tern eggs (United States)

    US Fish and Wildlife Service, Department of the Interior — The status of environmental contamination and its possible effects on living resources in the St. Lawrence River and Niagara River ecosystems has been the subject of...

  3. Chiral recognition of pinacidil and its 3-pyridyl isomer by canine cardiac and smooth muscle: Antagonism by sulfonylureas

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, M.I.; Wiest, S.A.; Zimmerman, K.M.; Ertel, P.J.; Bemis, K.G.; Robertson, D.W. (Eli Lilly and Company, Indianapolis, IN (USA))


    Pinacidil, a potassium channel opener (PCO), relaxes vascular smooth muscle by increasing potassium ion membrane conductance, thereby causing membrane hyperpolarization. PCOs also act on cardiac muscle to decrease action potential duration (APD) selectively. To examine the enantiomeric selectivity of pinacidil, the stereoisomers of pinacidil (a 4-pyridylcyanoguanidine) and its 3-pyridyl isomer (LY222675) were synthesized and studied in canine Purkinje fibers and cephalic veins. The (-)-enantiomers of both pinacidil and LY222675 were more potent in relaxing phenylephrine-contracted cephalic veins and decreasing APD than were their corresponding (+)-enantiomers. The EC50 values for (-)-pinacidil and (-)-LY222675 in relaxing cephalic veins were 0.44 and 0.09 microM, respectively. In decreasing APD, the EC50 values were 3.2 microM for (-)-pinacidil and 0.43 microM for (-)-LY222675. The eudismic ratio was greater for the 3-pyridyl isomer than for pinacidil in both cardiac (71 vs. 22) and vascular (53 vs. 17) tissues. (-)-LY222675 and (-)-pinacidil (0.1-30 microM) also increased 86Rb efflux from cephalic veins to a greater extent than did their respective optical antipodes. The antidiabetic sulfonylurea, glyburide (1-30 microM), shifted the vascular concentration-response curve of (-)-pinacidil to the right by a similar extent at each inhibitor concentration. Glipizide also antagonized the response to (-)-pinacidil, but was about 1/10 as potent with a maximal shift occurring at 10 and 30 microM. Glyburide antagonized the vascular relaxant effects of 0.3 microM (-)-LY222675 (EC50, 2.3 microM) and reversed the decrease in APD caused by 3 microM (-)-LY222675 (EC50, 1.9 microM). Nitroprusside did not alter 86Rb efflux, and vascular relaxation induced by sodium nitroprusside was unaffected by sulfonylureas.

  4. Al13H-: Hydrogen atom site selectivity and the shell model (United States)

    Grubisic, A.; Li, X.; Stokes, S. T.; Vetter, K.; Ganteför, G. F.; Bowen, K. H.; Jena, P.; Kiran, B.; Burgert, R.; Schnöckel, H.


    Using a combination of anion photoelectron spectroscopy and density functional theory calculations, we explored the influence of the shell model on H atom site selectivity in Al13H-. Photoelectron spectra revealed that Al13H- has two anionic isomers and for both of them provided vertical detachment energies (VDEs). Theoretical calculations found that the structures of these anionic isomers differ by the position of the hydrogen atom. In one, the hydrogen atom is radially bonded, while in the other, hydrogen caps a triangular face. VDEs for both anionic isomers as well as other energetic relationships were also calculated. Comparison of the measured versus calculated VDE values permitted the structure of each isomer to be confirmed and correlated with its observed photoelectron spectrum. Shell model, electron-counting considerations correctly predicted the relative stabilities of the anionic isomers and identified the stable structure of neutral Al13H.

  5. Approximate Inertial Coordinate System Selections for Rotate Problems the Gravitational Field of a Celestial Body Higher than the Object Being Rotated%旋转问题一级近似惯性坐标系的选取--比被绕行物体高一级天体的引力场

    Institute of Scientific and Technical Information of China (English)



    在旋转问题中,坐标系的选取至关重要,否则会因角速度测量不准而出现错误。旋转问题一级近似惯性坐标系,应该选取比被绕行物体高一级的天体引力场:(1)一般的旋转问题--固定在地球上的直角坐标系;(2)卫星绕地球旋转问题--日心-地心直角坐标系;(3)地球绕太阳旋转问题--银河系心-日心直角坐标系。在天体物理学中,质量计算不准和旋转角速度测量不准导致黑洞猜想。%Selection of the coordinate system is essential for rotate problem.Otherwise,mistakes may occur due to inaccurate measurement of angular speed. Approximate inertial coordinate system selections for rotate problems should be the gravitational field of a celestial body higher than the object being rotated:(1) the earth fixed Cartesian coordinate system for normal rotation problem;(2) heliocentric-geocentric Cartesian coordinate system for satellites orbiting the earth;(3) the Galaxy Heart-heliocentric Cartesian coordinates for Earth's rotation around the sun.In astrophysics,mass calculation error and angular velocity measurement error lead to a black hole conjecture.

  6. Supramolecular conformational effects in the electrocatalytic properties of electrostatic assembled films of meso(3- and 4-pyridyl) isomers of tetraruthenated porphyrins

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Ildemar; Toma, Henrique E.; Araki, Koiti [Sao Paulo Univ., SP (Brazil). Inst. de Quimica]. E-mail:; Eberlin, Marcos N.; Tomazela, Daniela M. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica


    Meso(3- and 4-pyridyl)porphyrins coordinated to four [Ru(bipy){sub 2}Cl]{sup +} complexes, M(3-TRPyP) or M(4-TRPyP), where M=2H{sup +} and Zn{sup 2+}, have been obtained and characterized by electrochemistry, spectroscopy and mass spectrometry. Layer-by-layer electrostatic assembled films with tetrasulfonated phthalocyaninatecuprate(II) anion, CuTSPc, displayed distinct electrocatalytic activity towards sulfite and nitrite oxidation. In general, the films derived from the M(4-TRPyP) isomers are more effective for the oxidation of nitrite, whereas those containing the M(3-TRPyP) isomers are more efficient for the oxidation of sulfite. The results demonstrated the influence of molecular geometry on the active sites of porphyrinic nano materials, enhancing the electron-transfer process in the M(3-TRPyP) derivative. This effect results from changes in the chemical environment around the active sites, induced by the contrasting molecular packing interactions with CuTSPc. (author)

  7. Adsorption Kinetics in Nanoscale Porous Coordination Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Nune, Satish K.; Thallapally, Praveen K.; McGrail, Benard Peter; Annapureddy, Harsha V. R.; Dang, Liem X.; Mei, Donghai; Karri, Naveen; Alvine, Kyle J.; Olszta, Matthew J.; Arey, Bruce W.; Dohnalkova, Alice


    Nanoscale porous coordination polymers were synthesized using simple wet chemical method. The effect of various polymer surfactants on colloidal stability and shape selectivity was investigated. Our results suggest that the nanoparticles exhibited significantly improved adsorption kinetics compared to bulk crystals due to decreased diffusion path lengths and preferred crystal plane interaction.

  8. Solvation effects on brain uptakes of isomers of 99mTc brain imaging agents

    Institute of Scientific and Technical Information of China (English)


    Analysis of electrostatic hydration free energies of the isomers of the 99mTc-BAT and 99mTc-DADT complexes is carried out using the computer simulation technique. The results show that not only a correlation exists between the logarithm of the brain uptake and the electrostatic hydration free energy for the isomers of 99mTc-brain radiopharmaceuticals, but also a linear relationship exists between the logarithm of the ratio of the brain uptake of the syn isomer to that of the anti one and the difference between the electrostatic hydration free energy of the syn-isomer and that of the anti one. Furthermore, the investigation on the important factors influencing the brain uptakes of 99mTc-radiopharmaceuticals and the reasons of the different biodistribution of the isomers of the 99mTc-complexes is explored at the molecular level. The results may provide a reference for the rational drug design of brain imaging agents.

  9. Experimental and theoretical cross sections for positron scattering from the pentane isomers (United States)

    Chiari, L.; Zecca, A.; Blanco, F.; García, G.; Brunger, M. J.


    Isomerism is ubiquitous in chemistry, physics, and biology. In atomic and molecular physics, in particular, isomer effects are well known in electron-impact phenomena; however, very little is known for positron collisions. Here we report on a set of experimental and theoretical cross sections for low-energy positron scattering from the three structural isomers of pentane: normal-pentane, isopentane, and neopentane. Total cross sections for positron scattering from normal-pentane and isopentane were measured at the University of Trento at incident energies between 0.1 and 50 eV. Calculations of the total cross sections, integral cross sections for elastic scattering, positronium formation, and electronic excitations plus direct ionization, as well as elastic differential cross sections were computed for all three isomers between 1 and 1000 eV using the independent atom model with screening corrected additivity rule. No definitive evidence of a significant isomer effect in positron scattering from the pentane isomers appears to be present.

  10. Thermodynamics and Kinetics of Guest-Induced Switching between “Basket Handle” Porphyrin Isomers

    Directory of Open Access Journals (Sweden)

    Alexander B. C. Deutman


    Full Text Available The synthesis and switching properties of two “basket handle” porphyrin isomers is described. The cis-oriented meso-phenyl groups of these porphyrins are linked at their ortho-positons via benzocrown-ether-based spacers, which as a result of slow atropisomerization are located either on the same side of the porphyrin plane (cis, or on opposite sides (trans. In solution, the cis-linked isomer slowly isomerizes in the direction of the thermodynamically more stable trans-isomer. In the presence of viologen (N,N'-dialkyl-4,4'-bipyridinium derivatives, which have different affinities for the two isomers, the isomerization equilibrium could be significantly influenced. In addition, the presence of these guests was found to enhance the rate of the switching process, which was suggested to be caused by favorable interactions between the positively charged guest and the crown ethers of the receptor, stabilizing the transition state energies of the isomerization reaction between the two isomers.

  11. Surface behavior of amphiphiles in aqueous solution: a comparison between different pentanol isomers. (United States)

    Walz, M-M; Caleman, C; Werner, J; Ekholm, V; Lundberg, D; Prisle, N L; Öhrwall, G; Björneholm, O


    Position isomerism is ubiquitous in atmospheric oxidation reactions. Therefore, we have compared surface-active oxygenated amphiphilic isomers (1- and 3-pentanol) at the aqueous surface with surface- and chemically sensitive X-ray photoelectron spectroscopy (XPS), which reveals information about the surface structure on a molecular level. The experimental data are complemented with molecular dynamics (MD) simulations. A concentration-dependent orientation and solvation of the amphiphiles at the aqueous surface is observed. At bulk concentrations as low as around 100 mM, a monolayer starts to form for both isomers, with the hydroxyl groups pointing towards the bulk water and the alkyl chains pointing towards the vacuum. The monolayer (ML) packing density of 3-pentanol is approx. 70% of the one observed for 1-pentanol, with a molar surface concentration that is approx. 90 times higher than the bulk concentration for both molecules. The molecular area at ML coverage (≈100 mM) was calculated to be around 32 ± 2 Å(2) per molecule for 1-pentanol and around 46 ± 2 Å(2) per molecule for 3-pentanol, which results in a higher surface concentration (molecules per cm(2)) for the linear isomer. In general we conclude therefore that isomers - with comparable surface activities - that have smaller molecular areas will be more abundant at the interface in comparison to isomers with larger molecular areas, which might be of crucial importance for the understanding of key properties of aerosols, such as evaporation and uptake capabilities as well as their reactivity.

  12. Coordinating Interactions: The Event Coordination Notation

    DEFF Research Database (Denmark)

    Kindler, Ekkart

    on a much more technical level. The Event Coordination Notation (ECNO) allows modelling the behaviour of an application on a high level of abstraction that is closer to the application’s domain than to the software realizing it. Still, these models contain all necessary details for actually executing...... implementation of ECNO, which consists of a modelling environment based on Eclipse and the Eclipse Modeling Framework (EMF) and an execution engine, which fully supports all the concepts and features of ECNO discussed in this technical report. All the examples are based on EMF, but the ECNO Engine can be used......The purpose of a domain model is to concisely capture the concepts of an application’s domain, and their relation among each other. Even though the main purpose of domain models is not on implementing the application, major parts of an application can be generated from the application’s domain...

  13. Discrimination of 1,1-difluoroethylene nuclear spin isomers in the presence of non-adiabatic coupling terms (United States)

    Gómez, Sandra; Oppel, Markus; González, Leticia


    The possibility to discriminate the ortho and para nuclear spin isomers of 1,1-difluoroethylene via their excited state dynamics is studied using wavepacket propagations including non-adiabatic couplings. The two nuclear spin isomers are connected via a torsional motion around the double bond. Photo-excitation induces a different interference pattern, with different torsional periods - a fact that can be exploited to distinguish, and eventually separate the nuclear spin isomers using femtosecond pump-probe experiments. The inclusion of non-adiabatic couplings results in a slowdown of the wavepacket, increasing the torsional periods of the nuclear spin isomers.

  14. In vitro interaction study of retinoic acid isomers with telmisartan and amlodipine by equilibrium dialysis method using UV spectroscopy (United States)

    Varghese, Susheel John; Johny, Sojimol K.; Paul, David; Ravi, Thengungal Kochupappy


    The in vitro protein binding of retinoic acid isomers (isotretinoin and tretinoin) and the antihypertensive drugs (amlodipine and telmisartan) was studied by equilibrium dialysis method. In this study, free fraction of drugs and the % of binding of drugs in the mixture to bovine serum albumin (BSA) were calculated. The influence of retinoic acid isomers on the % of protein binding of telmisartan and amlodipine at physiological pH (7.4) and temperature (37 ± 0.5 °C) was also evaluated. The in vitro displacement interaction study of drugs telmisartan and amlodipine on retinoic acid isomers and also interaction of retinoic acid isomers on telmisartan and amlodipine were carried out.

  15. Coordination studies of copper(II), cobalt(II) and iron(II) with isomeric pyridyl-tetrazole ligands

    DEFF Research Database (Denmark)

    Bond, A. D.; Fleming, A.; Gaire, J.


    The reaction of 2-(2H-tetrazol-5-yl)pyridine (L1) with 1,6-dibromohexane results in formation of the isomers 2-(6 ''-bromohexyl)-(1-tetrazol-5-yl)pyridine (12) and 2-(6 ''-bromohexyl)-(2-tetrazol-5-yl)pyridine (L3). Coordination reactions of 12 and 13 with CuCl2 center dot 2H(2)O, Co(SCN)(2) and ...

  16. Quantifying linguistic coordination

    DEFF Research Database (Denmark)

    Fusaroli, Riccardo; Tylén, Kristian

    ). We employ nominal recurrence analysis (Orsucci et al 2005, Dale et al 2011) on the decision-making conversations between the participants. We report strong correlations between various indexes of recurrence and collective performance. We argue this method allows us to quantify the qualities......Language has been defined as a social coordination device (Clark 1996) enabling innovative modalities of joint action. However, the exact coordinative dynamics over time and their effects are still insufficiently investigated and quantified. Relying on the data produced in a collective decision...

  17. Introduction to Coordination Chemistry

    CERN Document Server

    Lawrance, Geoffrey Alan


    Introduction to Coordination Chemistry examines and explains how metals and molecules that bind as ligands interact, and the consequences of this assembly process. This book describes the chemical and physical properties and behavior of the complex assemblies that form, and applications that may arise as a result of these properties. Coordination complexes are an important but often hidden part of our world?even part of us?and what they do is probed in this book. This book distills the essence of this topic for undergraduate students and for research scientists.

  18. Coordinate Standard Measurement Development

    Energy Technology Data Exchange (ETDEWEB)

    Hanshaw, R.A.


    A Shelton Precision Interferometer Base, which is used for calibration of coordinate standards, was improved through hardware replacement, software geometry error correction, and reduction of vibration effects. Substantial increases in resolution and reliability, as well as reduction in sampling time, were achieved through hardware replacement; vibration effects were reduced substantially through modification of the machine component dampening and software routines; and the majority of the machine's geometry error was corrected through software geometry error correction. Because of these modifications, the uncertainty of coordinate standards calibrated on this device has been reduced dramatically.

  19. Method for determining monohydroxybenzo[a]pyrene isomers using column-switching high-performance liquid chromatography. (United States)

    Toriba, Akira; Nakamura, Hiroaki; Chetiyanukornkul, Thaneeya; Kizu, Ryoichi; Makino, Tsunehisa; Nakazawa, Hiroyuki; Yokoi, Tsuyoshi; Hayakawa, Kazuichi


    A method for determining monohydroxybenzo[a]pyrene (OHBaP) isomers using column-switching high-performance liquid chromatography with fluorescence detection was developed. Eleven of 12 isomers of OHBaP (all except 6-OHBaP) were separated on an alkylamide-type reversed-phase column and, via column-switching, on a beta-cyclodextrin-bonded silica gel column. The detection limits for the OHBaPs were in the range 0.3-8 pg/injection (S/N=3). By using this method, 1-, 3-, and 9-OHBaPs were identified as major metabolites of benzo[a]pyrene in vitro by human recombinant p450 1A1. The method was used to determine OHBaPs in the urine of a nonsmoker subject. After enzymatic hydrolysis of the conjugated metabolites by beta-glucuronidase/aryl sulfatase, the analytes were selectively adsorbed on blue rayon (a cellulose-supported copper phthalocyanine) from the urine matrix. Methanol as the eluting solvent from the rayon gave the best recoveries of OHBaPs and 1-hydroxypyrene (1-OHP) in the range of 91-103%, which was superior to that of the solid-phase extraction method. 1-OHP, a well-known biomarker of the exposure to polycyclic aromatic hydrocarbons, was simultaneously analyzed. Intra- and interday accuracy values for the determination of 3-OHBaP in 200 ml of urine were 95.5 and 100.9%, and those for 1-OHP were 96.4 and 103.6%, respectively. The intra- and interday precision values were 3.9 and 2.4% for 3-OHBaP and 2.4 and 3.2% for 1-OHP, respectively. In 11 kinds of isomers, only 3-OHBaP was detected in the human urine. Urinary concentration of 3-OHBaP was quantified at 0.5 ng/g creatinine concentration and the 3-OHBaP/1-OHP ratio was approximately 1/130.

  20. Transgenic expression of trehalulose synthase results in high concentrations of the sucrose isomer trehalulose in mature stems of field-grown sugarcane. (United States)

    Hamerli, Dénes; Birch, Robert G


    Sugarcane plants were developed that produce the sucrose isomers trehalulose and isomaltulose through expression of a vacuole-targeted trehalulose synthase modified from the gene in 'Pseudomonas mesoacidophila MX-45' and controlled by the maize ubiquitin (Ubi-1) promoter. Trehalulose concentration in juice increased with internode maturity, reaching about 600 mM, with near-complete conversion of sucrose in the most mature internodes. Plants remained vigorous, and trehalulose production in selected lines was retained over multiple vegetative generations under glasshouse and field conditions.

  1. Characterization of the low-lying 0+ and 2+ states in Ni68 via β decay of the low-spin Co68 isomer

    CERN Document Server

    Flavigny, F; Radulov, D; Darby, I J; De Witte, H; Diriken, J; Fedorov, D V; Fedosseev, V N; Fraile, L M; Huyse, M; Ivanov, V S; Köster, U; Marsh, B A; Otsuka, T; Popescu, L; Raabe, R; Seliverstov, M D; Shimizu, N; Sjödin, A M; Tsunoda, Y; Van den Bergh, P; Van Duppen, P; Van de Walle, J; Venhart, M; Walters, W B; Wimmer, K


    The low-energy structure of the neutron-rich nucleus Ni68 has been investigated by measuring the β decay of the low-spin isomer in Co68 selectively produced in the decay chain of Mn68. A revised level scheme has been built based on the clear identification of β-γ-E0 delayed coincidences. Transitions between the three lowest-lying 0+ and 2+ states are discussed on the basis of measured intensities or their upper limits for unobserved branches and state-of-the-art shell model calculations.

  2. Coordination failure caused by sunspots

    DEFF Research Database (Denmark)

    Beugnot, Julie; Gürgüç, Zeynep; Øvlisen, Frederik Roose


    In a coordination game with Pareto-ranked equilibria, we study whether a sunspot can lead to either coordination on an inferior equilibrium (mis-coordination) or to out-of equilibrium behavior (dis-coordination). While much of the literature searches for mechanisms to attain coordination...... on the efficient equilibrium, we consider sunspots as a potential reason for coordination failure. We conduct an experiment with a three player 2x2x2 game in which coordination on the efficient equilibrium is easy and should normally occur. In the control session, we find almost perfect coordination on the payoff......-dominant equilibrium, but in the sunspot treatment, dis-coordination is frequent. Sunspots lead to significant inefficiency, and we conclude that sunspots can indeed cause coordination failure....

  3. Isomer discrimination of polycyclic aromatic hydrocarbons in the Murchison meteorite by resonant ionization. (United States)

    Callahan, Michael P; Abo-Riziq, Ali; Crews, Bridgit; Grace, Louis; de Vries, Mattanjah S


    We have used two-color resonant two-photon ionization (2C-R2PI) mass spectrometry to discriminate between isomers of polycyclic aromatic hydrocarbons in the Murchison meteorite. We measured the 2C-R2PI spectra of chrysene and triphenylene seeded in a supersonic jet by laser desorption. Since each isomer differs in its R2PI spectrum, we can distinguish between isomers using wavelength dependent ionization and mass spectrometry. We found both chrysene and triphenylene in sublimates from carbonaceous residue obtained by acid demineralization of the Murchison meteorite. Their R2PI mass spectra show only the molecular ion, even though these samples contain a complex inventory of organic molecules.

  4. Study of the separation method of structural isomer using Magneto-Archimedes method

    Energy Technology Data Exchange (ETDEWEB)

    Mori, T.; Kobayadhi, T.; Mishima, F.; Akiyama, Y.; Nishijima, Shigehiro [Osaka University, Osaka (Japan)


    Organic compounds have a problem that the separation of structural isomer in the preparation process requires high energy consumption. This study proposes a new separation method of structural isomer using Magneto- Archimedes method. Firstly, the levitation height of 1, 6-DDA and 1, 10-DDA was respectively calculated by simulation of the forces acting on the particles under magnetic field, and it was indicated that they could be separated by the difference of levitation height. To confirm the phenomenon experimentally, white powders of 1, 6-DDA and 1, 10-DDA were formed into pellets, and were soaked in manganese chloride solution. Then the solution was put on the center of the cryostat of HTS bulk magnet (maximum magnetic flux density is 3T). As a result, it was confirmed that the separation of structural isomer by difference of levitation height could be possible.

  5. [GC-FTIR analysis of structural isomers from hydrogenation products of p-phenylphenol]. (United States)

    Xin, Jun-Na; Xu, Qiang; Zhang, Hua; Yang, Xi-Chuan; Lü, Lian-Hai


    The hydrogenation of p-phenylphenol is a consecutive and parallel complex reaction. Owing to the difference in the hydrogenation ability of the two benzene rings in pphenylphenol, the hydrogenation products contained several structural isomers, which can not be identified by normal analytical method. However, the reaction mixture was effectively separated and identified by GC-FTIR technique. According to the characteristic wave numbers of benzene ring substituted at different positions, the main product was confirmed to be p-cyclohexylphenol, and the two typical by-products were p-phenylcyclohexanol and p-cyclohexylcyclohexanol, respectively. Each product has several stereo-isomers. GC-MS, melting point measurement and NMR proved the accuracy of GC-FTIR results, indicating that GC-IR is an useful and rapid method for analyzing structural isomers of organic compounds.

  6. How to avoid mass transfer limitations in ozonation kinetics of phenylphenol isomers?

    Directory of Open Access Journals (Sweden)

    Olak-Kucharczyk Magdalena


    Full Text Available Ozonation is a heterogeneous process of chemical absorption often controlled by a gas-liquid mass transfer rate. This paper presents the results of kinetics in a reaction between phenylphenol isomers and ozone. The degradation of phenylphenol isomers during ozonation proceeds quite fast. In order to avoid the influence of mass transfer limitation the kinetics experiments were conducted in a homogenous liquid-liquid system. The second-order rate constants were determined using classical and competition methods, which are especially recommended for fast reactions. The determined rate constants at pH 2 using the two different methods are almost the same. The increase of pH causes an increase of rate constants for the reaction of phenylphenol isomers with ozone.

  7. Effect of isomers of hydroxybenzoic acid on the growth and metabolism of Chlorella vulgaris Beijerinck (Chlorophyceae

    Directory of Open Access Journals (Sweden)

    Andrzej Bajguz


    Full Text Available The isomers o-, m-, and p- of hydroxybenzoic acid (HBA in the concentration range 10-1-10-4 M in the unicellular green alga Chlorella vulgaris (Chlorophyceae display marked biological activity. The o-HBA isomer, commonly known as salicylic acid, in a concentration of 10-4 M exerted the most stimulating effect on the parameters analysed (the number of cells, dry mass, the content of chlorophylls a and h, carotenoids, soluble proteins and their secretion, monosaccharides, DNA and RNA whereas p-HBA had weak stimulating properties. On the other hand, m-HBA had a weak inhibitory effect on the growth of C. vulgaris and all the biochemical parameters analysed in comparison with the control culture of algae devoid of HBA isomers.

  8. Decay of the 67-μs Isomer in 142pm

    Institute of Scientific and Technical Information of China (English)

    柳敏良; 张玉虎; 周小红; 郭应祥; 雷相国; 刘忠; 何建军; 温书贤; 吴晓光; 袁观俊


    Excited states in 142pm are investigated via the 128 Te(19F, 5n)142pm reaction at beam energies from 75 to 95 MeV by using techniques of in-beam γ-ray spectroscopy. Measurements of γ-ray excitation function, X-γ and γ-γ-tcoincidences are performed with 10 BGO(AC)HPGe detectors. Decay of the previously known 67-μs isomer in 142Pm is observed and added into the new level scheme. This isomer is definitely placed at the excitation energy of 2828.5 keV. The spin of this isomer is suggested to be 13h according to the measured γ-ray anisotropies.

  9. Activation of Reactive MALDI Adduct Ions Enables Differentiation of Dihydroxylated Vitamin D Isomers (United States)

    Qi, Yulin; Müller, Miriam J.; Volmer, Dietrich A.


    Vitamin D compounds are secosteroids, which are best known for their role in bone health. More recent studies have shown that vitamin D metabolites and catabolites such as dihydroxylated species (e.g., 1,25- and 24,25-dihydroxyvitamin D3) play key roles in the pathologies of various diseases. Identification of these isomers by mass spectrometry is challenging and currently relies on liquid chromatography, as the isomers exhibit virtually identical product ion spectra under collision induced dissociation conditions. Here, we developed a simple MALDI-CID method that utilizes ion activation of reactive analyte/matrix adducts to distinguish isomeric dihydroxyvitamin D3 species, without the need for chromatography separation or chemical derivatization techniques. Specifically, reactive 1,5-diaminonaphthalene adducts of dihydroxyvitamin D3 compounds formed during MADI were activated and specific cleavages in the secosteroid's backbone structure were achieved that produced isomer-diagnostic fragment ions. [Figure not available: see fulltext.

  10. Effects of pentanol isomers on the phase behavior of phospholipid bilayer membranes. (United States)

    Griffin, Kathryn L; Cheng, Chih-Yin; Smith, Eric A; Dea, Phoebe K


    Differential scanning calorimetry (DSC) was used to analyze the thermotropic phase behavior of dipalmitoylphosphatidylcholine (DPPC) bilayers in the presence of pentanol isomers. The concentration of each pentanol isomer needed to induce the interdigitated phase was determined by the appearance of a biphasic effect in the main transition temperatures, the onset of a hysteresis associated with the main transition from the gel-to-liquid crystalline phase, and the disappearance of the pretransition. Lower threshold concentrations were found to correlate with isomers of greater alkyl chain length while branching of the alkyl chain was found to increase biphasic behavior. The addition of a methyl group to butanol systems drastically decreased threshold concentrations. However, as demonstrated in the DPPC/neopentanol system, branching of the alkyl chain away from the -OH group lowers the threshold concentration while maintaining a biphasic effect.

  11. Reduction of MTT to Purple Formazan by Vitamin E Isomers in the Absence of Cells. (United States)

    Lim, Su-Wen; Loh, Hwei-San; Ting, Kang-Nee; Bradshaw, Tracey Dawn; Allaudin, Zeenathul Nazariah


    The yellow tetrazolium salt 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) is widely used to determine cell viability in cell proliferation and cytotoxic assays. MTT is reduced by metabolically active cells to form an insoluble purple formazan product that is quantifiable by spectrophotometry. It is the most common and direct assay for cell viability. However, in this present study, we demonstrated that the vitamin E isomers α-β-γ-δ-tocotrienols and α-tocopherol were able to reduce MTT into a formazan product, despite the absence of living cells. For comparison, a second method for determining cell viability, which is the neutral red uptake assay, was used in parallel with the MTT assay. The results showed that neutral red did not interact with the vitamin E isomers. Our findings suggest that the MTT assay is not suitable for studying the proliferative effects of vitamin E isomers on cell growth.

  12. New μs isomers in the neutron-rich {sup 210}Hg nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Gottardo, A., E-mail: [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, 35020 (Italy); Dipartimento di Fisica dell' Università degli Studi di Padova, Padova, 35131 (Italy); Valiente-Dobón, J.J. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro, 35020 (Italy); Benzoni, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milano, 20133 (Italy); Gadea, A. [Instituto de Física Corpuscular, CSIC-Universitat de València, València, E-46980 (Spain); Lunardi, S. [Dipartimento di Fisica dell' Università degli Studi di Padova, Padova, 35131 (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova, 35131 (Italy); Boutachkov, P. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, D-64291 (Germany); Bruce, A.M. [School of Computing, Engineering and Mathematics, University of Brighton, Brighton, BN2 4GJ (United Kingdom); Górska, M. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, D-64291 (Germany); Grebosz, J. [Niewodniczanski Institute of Nuclear Physics, Polish Academy of Science, Krakow, PL-31-342 (Poland); Pietri, S. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, D-64291 (Germany); Podolyák, Zs. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Pfützner, M. [Faculty of Physics, University of Warsaw, Warsaw, PL-00681 (Poland); Regan, P.H. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Weick, H. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, D-64291 (Germany); Alcántara Núñez, J. [Universidade de Santiago de Compostela, Santiago de Compostela, E-175706 (Spain); and others


    Neutron-rich nuclei in the lead region, beyond N=126, have been studied at the FRS-RISING setup at GSI, exploiting the fragmentation of a primary uranium beam. Two isomeric states have been identified in {sup 210}Hg: the 8{sup +} isomer expected from the seniority scheme in the νg{sub 9/2} shell and a second one at low spin and low excitation energy. The decay strength of the 8{sup +} isomer confirms the need of effective three-body forces in the case of neutron-rich lead isotopes. The other unexpected low-lying isomer has been tentatively assigned as a 3{sup −} state, although this is in contrast with theoretical expectations.

  13. High-performance liquid chromatography separation of cis-trans anthocyanin isomers from wild Lycium ruthenicum Murr. employing a mixed-mode reversed-phase/strong anion-exchange stationary phase. (United States)

    Jin, Hongli; Liu, Yanfang; Guo, Zhimou; Yang, Fan; Wang, Jixia; Li, Xiaolong; Peng, Xiaojun; Liang, Xinmiao


    The cis-trans isomerism is a common phenomenon for acylated anthocyanins. Nevertheless, few studies reported effective methods for the preparation of isomeric anthocyanins from natural products. In this work, a high-performance liquid chromatography (HPLC) method was developed to efficiently purify anthocyanin isomers from Lycium ruthenicum Murr. based on a mixed-mode reversed-phase/strong anion-exchange column (named XCharge C8SAX). Four commercially available columns were evaluated with a pair of isomeric anthocyanins, and the results demonstrated that the XCharge C8SAX column exhibited improved selectivity and column efficiency for the isomers. The chromatographic parameters, including pH, organic content, and ionic strength, were investigated. Optimal separation quality for the anthocyanin isomers was achieved on the XCharge C8SAX column. Six pure anthocyanins, including two pairs of cis-trans isomeric anthocyanins with one new anthocyanin, were purified from L. ruthenicum and identified. All of the results indicated that this method is an effective way to separate anthocyanins, especially for cis-trans isomers.

  14. Coordinating Work with Groupware

    DEFF Research Database (Denmark)

    Pors, Jens Kaaber; Simonsen, Jesper


    One important goal of employing groupware is to make possible complex collaboration between geographically distributed groups. This requires a dual transformation of both technology and work practice. The challenge is to re­duce the complexity of the coordination work by successfully inte­grating...

  15. Rockin' Readers Coordinator Handbook. (United States)

    Alachua County Schools, Gainesville, FL.

    This coordinator's handbook describes the "Rockin' Readers" program, in which senior-citizen volunteers are matched with specifically targeted at-risk children (usually of kindergarten age or slightly older) in Alachua County, Florida, who tested below their peer group in language development and reading readiness skills. The handbook…

  16. Explicit Spin Coordinates

    CERN Document Server

    Hunter, G; Hunter, Geoffrey; Schlifer, Ian


    The recently established existence of spherical harmonic functions, $Y_\\ell^{m}(\\theta,\\phi)$ for half-odd-integer values of $\\ell$ and $m$, allows for the introduction into quantum chemistry of explicit electron spin-coordinates; i.e. spherical polar angles $\\theta_s, \\phi_s$, that specify the orientation of the spin angular momentum vector in space. In this coordinate representation the spin angular momentum operators, $S^2, S_z$, are represented by the usual differential operators in spherical polar coordinates (commonly used for $L^2, L_z$), and their electron-spin eigenfunctions are $\\sqrt{\\sin\\theta_s} \\exp(\\pm\\phi_s/2)$. This eigenfunction representation has the pedagogical advantage over the abstract spin eigenfunctions, $\\alpha, \\beta,$ that ``integration over spin coordinates'' is a true integration (over the angles $\\theta_s, \\phi_s$). In addition they facilitate construction of many electron wavefunctions in which the electron spins are neither parallel nor antiparallel, but inclined at an interme...

  17. Equilibria with Coordination Failures

    NARCIS (Netherlands)

    Herings, P.J.J.; van der Laan, G.; Talman, A.J.J.


    This paper extends the recent literature on equilibria with coordination failures to arbitrary convex sets of admissible prices.We introduce a new equilibrium concept, called quantity constrained equilibrium (QCE), giving a uni.ed treatment to all cases considered in the literature so far.At a QCE

  18. Block coordination copolymers (United States)

    Koh, Kyoung Moo; Wong-Foy, Antek G; Matzger, Adam J; Benin, Annabelle I; Willis, Richard R


    The present invention provides compositions of crystalline coordination copolymers wherein multiple organic molecules are assembled to produce porous framework materials with layered or core-shell structures. These materials are synthesized by sequential growth techniques such as the seed growth technique. In addition, the invention provides a simple procedure for controlling functionality.

  19. Experimental investigation of the low temperature oxidation of the five isomers of hexane. (United States)

    Wang, Zhandong; Herbinet, Olivier; Cheng, Zhanjun; Husson, Benoit; Fournet, René; Qi, Fei; Battin-Leclerc, Frédérique


    The low-temperature oxidation of the five hexane isomers (n-hexane, 2-methyl-pentane, 3-methyl-pentane, 2,2-dimethylbutane, and 2,3-dimethylbutane) was studied in a jet-stirred reactor (JSR) at atmospheric pressure under stoichiometric conditions between 550 and 1000 K. The evolution of reactant and product mole fraction profiles were recorded as a function of the temperature using two analytical methods: gas chromatography and synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). Experimental data obtained with both methods were in good agreement for the five fuels. These data were used to compare the reactivity and the nature of the reaction products and their distribution. At low temperature (below 800 K), n-hexane was the most reactive isomer. The two methyl-pentane isomers have about the same reactivity, which was lower than that of n-hexane. 2,2-Dimethylbutane was less reactive than the two methyl-pentane isomers, and 2,3-dimethylbutane was the least reactive isomer. These observations are in good agreement with research octane numbers given in the literature. Cyclic ethers with rings including 3, 4, 5, and 6 atoms have been identified and quantified for the five fuels. While the cyclic ether distribution was notably more detailed than in other literature of JSR studies of branched alkane oxidation, some oxiranes were missing among the cyclic ethers expected from methyl-pentanes. Using SVUV-PIMS, the formation of C2-C3 monocarboxylic acids, ketohydroperoxides, and species with two carbonyl groups have also been observed, supporting their possible formation from branched reactants. This is in line with what was previously experimentally demonstrated from linear fuels. Possible structures and ways of decomposition of the most probable ketohydroperoxides were discussed. Above 800 K, all five isomers have about the same reactivity, with a larger formation from branched alkanes of some unsaturated species, such as allene and propyne, which

  20. Quantitative Analysis of the Distribution of cis-Eicosenoic Acid Positional Isomers in Marine Fishes from the Indian Ocean. (United States)

    Senarath, Samanthika; Yoshinaga, Kazuaki; Nagai, Toshiharu; Yoshida, Akihiko; Beppu, Fumiaki; Jayasinghe, Chamila; Devadawson, Chandravathany; Gotoh, Naohiro


    This study investigated the occurrence and distribution of cis-eicosenoic acid (c-20:1) positional isomers in fishes from the Indian Ocean and compared to those from the Pacific and Atlantic Ocean. Lipids were extracted from the edible part of the fish and then methylated. The eicosenoic acid methyl ester fraction was separated from total fatty acid methyl esters by reversed-phase HPLC and quantitatively analyzed using a GC-FID fitted with the SLB-IL111 highly polar GC column. c14-20:1 was used as an internal standard. The results indicated that the highest levels of c-20:1 positional isomers were found in fishes from the Pacific Ocean (saury, 166.95±12.4 mg/g of oil), followed by the Atlantic Ocean (capelin, 162.7±3.5 mg/g of oil), and lastly in fishes from the Indian Ocean (goatfish, 34.39 mg/g of oil). With only a few exceptions, the most abundant 20:1 positional isomer found in fishes of the Indian and Atlantic Ocean was the c11-20:1 isomer (>50%) followed by the c13-20:1 isomer (<25%). Unusually, the c7-20:1 isomer was predominantly found in a few fishes such as the tooth ponyfish, longface emperor, and commerson's sole. The c9, c5, and c15-20:1 isomers were the least occurring in fishes from the Indian and Atlantic Ocean. In contrast, the c9-20:1 isomer was the principal isomer identified in fishes from the Pacific Ocean. The results revealed that the content and distribution of c-20:1 positional isomers varied among fishes in different oceans. The data presented in the current study are the first to report on the distribution of c-20:1 positional isomers in fishes from the Indian Ocean.

  1. Solvent effects on reactivity properties of dicarba-closo-dodecarboranes isomers (United States)

    Junqueira, G. M. A.; Rocha, L. C.; Cotta, V. T.; César, E. T.


    In this Letter, a discussion on global reactivity indexes - electronic chemical potential (μ), chemical hardness (η) and electrophilicity (ω) - for dicarba-closo-dodecarboranes isomers, in gas phase and aqueous solution is reported. A sequential Monte Carlo/quantum mechanics methodology (S-MC/QM) was used in simulations. The results obtained showed the solvent must be considered on reactivity properties of the studied compounds. Generally, the solvated isomers become softer (η decreases) and the μ increases comparing to gas phase values, indicating the charge transfer from solvent to the solute.

  2. Tryptophan-Ethylester, the False (Unveiled) Melatonin Isomer in Red Wine (United States)

    Iriti, Marcello; Vigentini, Ileana


    Among the food plants, the presence of melatonin in grapes (Vitis vinifera L.) deserves particular attention because of the production of wine, an alcoholic beverage of economic relevance and with putative healthy effects. Furthermore, melatonin isomers have been detected in wine too. Recently, one of these isomers has been identified as tryptophan-ethylester, a compound with the same molecular weight of melatonin. In this Commentary, we briefly comment the source(s) of tryptophan-ethylester in wine and the putative nutritional role(s). PMID:25922582

  3. Laboratory data base for isomer-specific determination of polychlorinated biphenyls

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, T.R.; Campbell, R.D.; Stalling, D.L.; Little, R.L.; Petty, J.D.; Hogan, J.W.; Kaiser, E.M.


    A computer-assisted technique for quantitative determination of polychlorinated biphenyl isomers is described. PCB isomers were identified by use of a retention index system with n-alkyl trichloroacetates as retention index marker compounds. A laboratory data base system was developed to aid in editing and quantitation of data generated from capillary gas chromatographic data. Data base management was provided by computer programs written in DSM-11 (Digital Standard MUMPS) for the PDP-11 family of computers. 13 references, 4 figures, 2 tables.

  4. Laminar burning velocities and flame instabilities of butanol isomers-air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Xiaolei; Huang, Zuohua; Wu, Si; Li, Qianqian [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)


    Laminar burning velocities and flame instabilities of the butanol-air premixed flames and its isomers are investigated using the spherically expanding flame with central ignition at initial temperature of 428 K and initial pressures of 0.10 MPa, 0.25 MPa, 0.50 MPa and 0.75 MPa. Laminar burning velocities and sensitivity factor of n-butanol-air mixtures are computed using a newly developed kinetic mechanism. Unstretched laminar burning velocity, adiabatic temperature, Lewis number, Markstein length, critical flame radius and Peclet number are obtained over a wide range of equivalence ratios. Effect of molecular structure on laminar burning velocity of the isomers of butanol is analyzed from the aspect of C-H bond dissociation energy. Study indicates that although adiabatic flame temperatures of the isomers of butanol are the same, laminar burning velocities give an obvious difference among the isomers of butanol. This indicates that molecular structure has a large influence on laminar burning velocities of the isomers of butanol. Branching (-CH3) will decrease laminar burning velocity. Hydroxyl functional group (-OH) attaching to the terminal carbon atoms gives higher laminar burning velocity compared to that attaching to the inner carbon atoms. Calculated dissociation bond energies show that terminal C-H bonds have larger bond energies than that of inner C-H bonds. n-Butanol, no branching and with hydroxyl functional group (-OH) attaching to the terminal carbon atom, gives the largest laminar burning velocity. tert-Butanol, with highly branching and hydroxyl functional group (-OH) attaching to the inner carbon atom, gives the lowest laminar burning velocity. Laminar burning velocities of iso-butanol and sec-butanol are between those of n-butanol and tert-butanol. The instant of transition to cellularity is experimentally determined for the isomers of butanol and subsequently interpreted on the basis of hydrodynamic and diffusion-thermal instabilities. Little effect

  5. Observation of a New (25/2+) Isomer in 121Sb (United States)

    Kownacki, J.; Kisielinski, M.; Kowalczyk, M.; Droste, Ch.; Morek, T.; Ruchowska, E.; Srebrny, J.; Wolinska-Cichocka, M.; Palacz, M.; Korman, A.; Andrzejewski, J.; KrXf3l, A.; Perkowski, J.; Lieder, R.; Mierzejewski, J.; Sankowska, I.


    The beam pulse structure of the HIL cyclotron and thick target gamma -gamma coincidence measurements in the in-beam and off-beam modes have been used to search for isomers in the A approx 120 mass region using heavy-ion reactions. The half-life of the 2721 keV, (25/2+) level in 121Sb was determined in the off-beam mode to be 167 pm 19 mu s. Two deexcitation sequences of this isomer are proposed. The isomeric state is considered to be of 3-quasiparticle nature pi (d5/2)nu (h11/22)10+.

  6. Systematic study of the synthesis and coordination of 2-(1,2,3-triazol-4-yl)-pyridine to Fe(II), Ni(II) and Zn(II); ion-induced folding into helicates, mesocates and larger architectures, and application to magnetism and self-selection. (United States)

    Wu, Nan; Melan, Caroline F C; Stevenson, Kristina A; Fleischel, Olivier; Guo, Huan; Habib, Fatemah; Holmberg, Rebecca J; Murugesu, Muralee; Mosey, Nicholas J; Nierengarten, Hélène; Petitjean, Anne


    With its facile synthesis, the pyridine-1,2,3-triazole chelate is an attractive building block for coordination-driven self-assembly. When two such chelates are bridged by a spacer and exposed to cations of octahedral geometrical preference, they generally self-assemble into dinuclear triple-stranded structures in the solid state and in solution in the presence of non-coordinating counter-ions. In solution, a wider range of architectures may nevertheless form, depending on the nature of the spacer. A systematic study of the spacer and substitution pattern is therefore presented, which allows assessing the various factors affecting self-assembly around the pyridine-1,2,3-triazole chelate, as well as the stereochemical control in these architectures. Applications to chirality, magnetism and system selection are discussed, and involve Fe(ii), Ni(ii), Zn(ii) and Cu(i) cations.


    Directory of Open Access Journals (Sweden)

    B. Konakoglu


    Full Text Available Two coordinate systems used in Turkey, namely the ED50 (European Datum 1950 and ITRF96 (International Terrestrial Reference Frame 1996 coordinate systems. In most cases, it is necessary to conduct transformation from one coordinate system to another. The artificial neural network (ANN is a new method for coordinate transformation. One of the biggest advantages of the ANN is that it can determine the relationship between two coordinate systems without a mathematical model. The aim of this study was to investigate the performances of three different ANN models (Feed Forward Back Propagation (FFBP, Cascade Forward Back Propagation (CFBP and Radial Basis Function Neural Network (RBFNN with regard to 2D coordinate transformation. To do this, three data sets were used for the same study area, the city of Trabzon. The coordinates of data sets were measured in the ED50 and ITRF96 coordinate systems by using RTK-GPS technique. Performance of each transformation method was investigated by using the coordinate differences between the known and estimated coordinates. The results showed that the ANN algorithms can be used for 2D coordinate transformation in cases where optimum model parameters are selected.

  8. A selector for structural isomers of neutral molecules

    CERN Document Server

    Filsinger, Frank; von Helden, Gert; Küpper, Jochen; Meijer, Gerard


    We have selected and spatially separated the two conformers of 3-aminophenol (C$_6$H$_7$NO) present in a molecular beam. Analogous to the separation of ions based on their mass-to-charge ratios in a quadrupole mass filter, the neutral conformers are separated based on their different mass-to-dipole-moment ratios in an ac electric quadrupole selector. For a given ac frequency, the individual conformers experience different focusing forces, resulting in different transmissions through the selector. These experiments demonstrate that conformer-selected samples of large molecules can be prepared, offering new possibilities for the study of gas-phase biomolecules.

  9. Revised structure of a homonojirimycin isomer from Aglaonema treubii: first example of a naturally occurring alpha-homoallonojirimycin. (United States)

    Martin, O R; Compain, P; Kizu, H; Asano, N


    The structure of a homonojirimycin isomer isolated from Aglaonema treublii and originally proposed as alpha-3,4-di-epi-homonojirimycin was revised to alpha-4-epi-homonojirimycin 3 ("alpha-homoallonojirimycin") on the basis of NMR analysis and synthetic studies. Its activity as a glycosidase inhibitor is compared to that of other homonojirimycin isomers.

  10. Global Coordinate System (United States)


    Time in hours at Oh UT is GAST (hours) = GMST + E (41) GAST in radians is GASTo (radians) = GAST (hours) L (42) The angle e required for transforming...inertial coordinates to ECEF is- 6(radians) GASTo + 6.3003880.99 (ti - th) (43) o ~ooUT Mod ( E 27) where St.i - tohLjT = (JD -2.4 106). (JDOE -2.4 x

  11. International Monetary Policy Coordination


    Carlberg, Michael


    This paper studies the international coordination of monetary policies in the world economy. It carefully discusses the process of policy competition and the structure of policy cooperation. As to policy competition, the focus is on monetary competition between Europe and America. Similarly, as to policy cooperation, the focus is on monetary cooperation between Europe and America. The spillover effects of monetary policy are negative. The policy targets are price stability and full employment.

  12. Global coordination: weighted voting

    Directory of Open Access Journals (Sweden)

    Jan-Erik Lane


    Full Text Available In order to halt the depletion of global ecological capital, a number of different kinds of meetings between Governments of countries in the world has been scheduled. The need for global coordination of environmental policies has become ever more obvious, supported by more and more evidence of the running down of ecological capital. But there are no formal or binding arrangements in sight, as global environmental coordination suffers from high transaction costs (qualitative voting. The CO2 equivalent emissions, resulting in global warming, are driven by the unstoppable economic expansion in the global market economy, employing mainly fossil fuel generated energy, although at the same time lifting sharply the GDP per capita of several emerging countries. Only global environmental coordination on the successful model of the World Band and the IMF (quantitative voting can stem the rising emissions numbers and stop further environmental degradation. However, the system of weighted voting in the WB and the IMF must be reformed by reducing the excessive voting power disparities, for instance by reducing all member country votes by the cube root expression.

  13. Universal mechatronics coordinator (United States)

    Muir, Patrick F.


    Mechatronic systems incorporate multiple actuators and sensor which must be properly coordinated to achieve the desired system functionality. Many mechatronic systems are designed as one-of-a-kind custom projects without consideration for facilitating future system or alterations and extensions to the current syste. Thus, subsequent changes to the system are slow, different, and costly. It has become apparent that manufacturing processes, and thus the mechatronics which embody them, need to be agile in order to more quickly and easily respond to changing customer demands or market pressures. To achieve agility, both the hardware and software of the system need to be designed such that the creation of new system and the alteration and extension of current system is fast and easy. This paper describes the design of a Universal Mechatronics Coordinator (UMC) which facilitates agile setup and changeover of coordination software for mechatronic systems. The UMC is capable of sequencing continuous and discrete actions that are programmed as stimulus-response pairs, as state machines, or a combination of the two. It facilitates the modular, reusable programing of continuous actions such as servo control algorithms, data collection code, and safety checking routines; and discrete actions such as reporting achieved states, and turning on/off binary devices. The UMC has been applied to the control of a z- theta assembly robot for the Minifactory project and is applicable to a spectrum of widely differing mechatronic systems.

  14. Improving Project Manufacturing Coordination

    Directory of Open Access Journals (Sweden)

    Korpivaara Ville


    Full Text Available The objective of this research is to develop firms’ project manufacturing coordination. The development will be made by centralizing the manufacturing information flows in one system. To be able to centralize information, a deep user need assessment is required. After user needs have been identified, the existing system will be developed to match these needs. The theoretical background is achieved through exploring the literature of project manufacturing, development project success factors and different frameworks and tools for development project execution. The focus of this research is rather in customer need assessment than in system’s technical expertise. To ensure the deep understanding of customer needs this study is executed by action research method. As a result of this research the information system for project manufacturing coordination was developed to respond revealed needs of the stakeholders. The new system improves the quality of the manufacturing information, eliminates waste in manufacturing coordination processes and offers a better visibility to the project manufacturing. Hence it provides a solid base for the further development of project manufacturing.

  15. A spectroscopic study on the coordination and solution structures of the interaction systems between biperoxidovanadate complexes and the pyrazolylpyridine-like ligands. (United States)

    Yu, Xian-Yong; Deng, Lin; Zheng, Baishu; Zeng, Bi-Rong; Yi, Pinggui; Xu, Xin


    In order to understand the substitution effects of pyrazolylpyridine (pzpy) on the coordination reaction equilibria, the interactions between a series of pzpy-like ligands and biperoxidovanadate ([OV(O2)2(D2O)](-)/[OV(O2)2(HOD)](-), abbrv. bpV) have been explored using a combination of multinuclear ((1)H, (13)C, and (51)V) magnetic resonance, heteronuclear single quantum coherence (HSQC), and variable temperature NMR in a 0.15 mol L(-1) NaCl D2O solution that mimics the physiological conditions. Both the direct NMR data and the equilibrium constants are reported for the first time. A series of new hepta-coordinated peroxidovanadate species [OV(O2)2L](-) (L = pzpy-like chelating ligands) are formed due to several competitive coordination interactions. According to the equilibrium constants for products between bpV and the pzpy-like ligands, the relative affinity of the ligands is found to be pzpy > 2-Ester-pzpy ≈ 2-Me-pzpy ≈ 2-Amide-pzpy > 2-Et-pzpy. In the interaction system between bpV and pzpy, a pair of isomers (Isomers A and B) are observed in aqueous solution, which are attributed to different types of coordination modes between the metal center and the ligands, while the crystal structure of NH4[OV(O2)2(pzpy)]·6H2O (CCDC 898554) has the same coordination structure as Isomer A (the main product for pzpy). For the N-substituted ligands, however, Isomer A or B type complexes can also be observed in solution but the molar ratios of the isomer are reversed (i.e., Isomer B type is the main product). These results demonstrate that when the N atom in the pyrazole ring has a substitution group, hydrogen bonding (from the H atom in the pyrazole ring), the steric effect (from alkyl) and the solvation effect (from the ester or amide group) can jointly affect the coordination reaction equilibrium.

  16. The interstellar chemistry of C3H and C3H2 isomers (United States)

    Loison, Jean-Christophe; Agúndez, Marcelino; Wakelam, Valentine; Roueff, Evelyne; Gratier, Pierre; Marcelino, Núria; Reyes, Dianailys Nuñez; Cernicharo, José; Gerin, Maryvonne


    We report the detection of linear and cyclic isomers of C3H and C3H2 towards various starless cores and review the corresponding chemical pathways involving neutral (C3Hx with x = 1,2) and ionic (C3Hx+ with x = 1,2,3) isomers. We highlight the role of the branching ratio of electronic dissociative recombination (DR) reactions of C3H2+ and C3H3+ isomers, showing that the statistical treatment of the relaxation of C3H* and C3H2* produced in these DR reactions may explain the relative c,l-C3H and c,l-C3H2 abundances. We have also introduced in the model the third isomer of C3H2 (HCCCH). The observed cyclic-to-linear C3H2 ratio varies from 110 ± 30 for molecular clouds with a total density of about 1 × 104 molecules cm-3 to 30 ± 10 for molecular clouds with a total density of about 4 × 105 molecules cm-3, a trend well reproduced with our updated model. The higher ratio for molecular clouds with low densities is determined mainly by the importance of the H + l-C3H2 → H + c-C3H2 and H + t-C3H2 → H + c-C3H2 isomerization reactions.

  17. Ab Initio Investigations of the C2F4S Isomers and of Their Interconversions

    DEFF Research Database (Denmark)

    Shim, Irene; Vallano-Lorenzo, Sandra; Lisbona-Martin, Pilar


    The transition states and the activation energies for the unobserved isomerization reactions between the three possible C2F4S isomers with divalent sulfur, trifluorothioacetyl fluoride 1, tetrafluorothiirane 2, and trifluoroethenesulfenyl fluoride 3, have been determined by ab initio Hartree-Fock...

  18. Lactones 42. Stereoselective enzymatic/microbial synthesis of optically active isomers of whisky lactone. (United States)

    Boratyński, Filip; Smuga, Małgorzata; Wawrzeńczyk, Czesław


    Two different methods, enzyme-mediated reactions and biotrasformations with microorganisms, were applied to obtain optically pure cis- and trans-isomers of whisky lactone 4a and 4b. In the first method, eight alcohol dehydrogenases were investigated as biocatalysts to enantioselective oxidation of racemic erythro- and threo-3-methyloctane-1,4-diols (1a and 1b). Oxidation processes with three of them, alcohol dehydrogenases isolated from horse liver (HLADH) as well as recombinant from Escherichia coli and primary alcohol dehydrogenase (PADH I), were characterized by the highest degree of conversion with moderate enantioselectivity (ee=27-82%) of the reaction. In all enzymatic reactions enantiomerically enriched not naturally occurring isomers of trans-(-)-(4R,5S)-4b or cis-(+)-(4R,5R)-4a were formed preferentially. In the second strategy, based on microbial lactonization of γ-oxoacids, naturally occurring opposite isomers of whisky lactones were obtained. Trans-(+)-(4S,5R)-isomer (ee=99%) of whisky lactone 4b was stereoselectively formed as the only product of biotransformations of 3-methyl-4-oxooctanoic acid (5) catalyzed by Didimospheria igniaria KCH6651, Laetiporus sulphurens AM525, Chaetomium sp.1 KCH6670 and Saccharomyces cerevisiae AM464. Biotransformation of γ-oxoacid 5, in the culture of Beauveria bassiana AM278 and Pycnidiella resinae KCH50 afforded a mixtures of trans-(+)-(4S,5R)-4b with enantiomeric excess ee=99% and cis-(-)-(4S,5S)-4a with enantiomeric excesses ee=77% and ee=45% respectively.

  19. New Isomers in the Neutron-Rich Region Beyond 208Pb

    Directory of Open Access Journals (Sweden)

    Gottardo A.


    Full Text Available The region of neutron-rich nuclei beyond 208Pb has been very difficult to explore due to its high mass and exoticity. However, recent experimental improvements allowed one to perform a quite extended isomer decay spectroscopy of these nuclei.

  20. Influence of Si/Al ratio on hexane isomers adsorption equilibria

    NARCIS (Netherlands)

    Ferreira, A.F.P.; Mittelmeijer-Hazeleger, M.C.; Bliek, A.; Moulijn, J.A.


    In this work we aim to have a better knowledge of the influence of silica/alumina ratio (SAR) on the adsorption equilibrium of hexane isomers on MFI zeolites. With a manometric set-up coupled with a micro-calorimeter we did address adsorption properties and heats of adsorption of n-hexane, 2-methylp

  1. Structures, Vibrational Spectra, and Relative Energetics of CH3COIO3 Isomers

    Institute of Scientific and Technical Information of China (English)

    GE,Mao-Fa; MA,Chun-Ping


    The structures,vibrational spectra,relative energetics,and enthalpies of formation of CH3COlO3 isomers have been investigated with B3LYP,B3P86 and B3PW91 methods in conjugation with the 6-31+G(d),6-311+G(d,p)and 6-311++G(3df,3pd) basis sets.The CH3COOIO2 structure was found to be the most stable form among the isomers with an estimated enthalpy of formation of -314.6 kJ·mol-1.The enthalpies of formation for CH3COOOOI,CH3COOOIO and CH3COIO3 are -180.7,-184.9 and -50.6 kJ·mol-1,respectively.The implication of the formation of CH3COIO3 isomers from the atmospheric cross-reactions of the acetylperoxy (CH3COO2) and iodine monoxide (IO) radicals was examined and the possible dissociation products of the most likely CH3COIO3 isomers were determined.

  2. Beta decay of {sup 94}Pd and of the 71s isomer of {sup 94}Rh

    Energy Technology Data Exchange (ETDEWEB)

    Batist, L. [St. Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Department of Physics of the University ' ' Federico II' ' , Napoli (Italy); Blazhev, A. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany); University of Sofia, Sofia (Bulgaria); Doering, J. [University of Sofia, Sofia (Bulgaria); Grawe, H.; Kirchner, R.; Mazzocchi, C.; Plettner, C.; Roeckl, E. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany); Kavatsyuk, M.; Kavatsyuk, O. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany); National Taras Shevchenko University of Kyiv, Kyiv (Ukraine); La Commara, M.; Romoli, M. [Department of Physics of the University ' ' Federico II' ' , Napoli (Italy); Mukha, I. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany); University of Seville, Sevilla (Spain)


    The {beta} decay of {sup 94}Pd and of the 71s isomer of {sup 94}Rh was investigated by using total {gamma}-ray absorption techniques. Several levels in {sup 94}Rh are established, including a new low-lying isomer characterized by a half-life of 0.48(3) {mu}s and a de-exciting transition of 55keV. E2 multipolarity is determined for this transition by measuring the intensities of its {gamma}-rays and the characteristic X-rays from its electron conversion. On the basis of the measured reduced {beta}-decay transition rates to known {sup 94}Ru levels and shell model considerations, the spin-parity of the 71s and the 0.48{mu}s isomers of {sup 94}Rh is assigned to be (4{sup +}) and (2{sup +}), respectively. The {beta}-decay strength distributions measured for {sup 94}Pd and the 71s isomer of {sup 94}Rh yield Q{sub EC} values of 6700(320) and 9750(320)keV for these decays and give evidence for the population of those states below and above the magic N=50 gap that belong to both components of the 0g spin-orbit doublet. (orig.)

  3. Isomer production ratios and the angular momentum distribution of fission fragments (United States)

    Stetcu, I.; Talou, P.; Kawano, T.; Jandel, M.


    Latest generation fission experiments provide an excellent testing ground for theoretical models. In this contribution we compare the measurements for 235U(nth,f), obtained with the Detector for Advanced Neutron Capture Experiments (DANCE) calorimeter at Los Alamos Neutron Science Center (LANSCE), with our full-scale simulation of the primary fragment de-excitation, using the recently developed cgmf code, based on a Monte Carlo implementation of the Hauser-Feshbach theoretical model. We compute the isomer ratios as a function of the initial angular momentum of the fission fragments, for which no direct information exists. Comparison with the available experimental data allows us to determine the initial spin distribution. We also study the dependence of the isomer ratio on the knowledge of the low-lying discrete spectrum input for nuclear fission reactions, finding a high degree of sensitivity. Finally, in the same Hauser-Feshbach approach, we calculate the isomer production ratio for thermal neutron capture on stable isotopes, where the initial conditions (spin, excitation energy, etc.) are well understood. We find that with the current parameters involved in Hauser-Feshbach calculations, we obtain up to a factor of 2 deviation from the measured isomer ratios.

  4. Microsecond isomers in the odd-odd nucleus [sup 144]Tb

    Energy Technology Data Exchange (ETDEWEB)

    Sferrazza, M.; Bazzacco, D.; Lunardi, S.; Maglione, E. (INFN, Padua (Italy) Dipt. di Fisica, Padua Univ. (Italy)); Cardona, M.A.; Rico, J.; Facco, A. (INFN, Laboratori Nazionali di Legnaro (Italy)); De Angelis, G.; Bizzeti, P.G.; Bizzeti-Sona, A.M. (INFN, Florence (Italy) Dipt. di Fisica, Florence Univ. (Italy))


    Two new isomers with half-lives of 0.67(6) [mu]s and 2.8(3) [mu]s have been identified in the odd-odd nucleus [sup 144]Tb. A partial decay scheme is presented. An interpretation in the framework of the shell model is discussed for the low lying energy states. (orig.).

  5. Toward the laboratory identification of [O,N,S,S] isomers: Implications for biological NO chemistry (United States)

    Ayari, Tarek; Jaidane, Nejm-Eddine; Al Mogren, Muneerah Mogren; Francisco, Joseph S.; Hochlaf, Majdi


    Benchmark ab initio calculations are performed to investigate the stable isomers of [O,N,S,S]. These computations are carried out using coupled cluster (RCCSD(T)) and explicitly correlated coupled cluster methods (RCCSD(T)-F12). In addition to the already known cis isomer of SSNO, nine other stable forms are predicted. The most stable isomer is cis-OSNS. Nine structures are chain bent-bent with relatively large dipole moments which make them detectable, as cis-SSNO, by infrared, far-infrared, and microwave spectroscopies. We found also a C2v isomer (NS2O). Since these species are strongly suggested to play an important role as intermediates during the bioactive reaction products of the NO/H2S interaction, the rotational and vibrational spectroscopic parameters are presented to help aid the in vivo identification and assignment of these spectra. Results from this work show that [O,N,S,S] may play key roles during nitric oxide transport and deliver in biological media, as well as, provide an explanation for the weak characteristic of disulfide bridges within proteins.

  6. Prospects for measuring the $^{229}$Th isomer energy using a metallic magnetic microcalorimeter

    CERN Document Server

    Kazakov, G A; Sterba, J H; Fleischmann, A; Enss, C; Schumm, T


    The Thorium-229 isotope features a nuclear isomer state with extremely low energy. The currently most accepted energy value, $7.8 \\pm 0.5$\\,eV, was obtained from an indirect measurements using a NASA x-ray microcalorimeter with instrumental resolution (FWHM) of 26\\,eV. We study, how state-of-the-art magnetic metallic microcalorimeters with an energy resolution down to a few eV can be used to measure the isomer energy. Resolving the 29.18\\,keV doublet in the $\\gamma$-spectrum following the $\\alpha$-decay of Uranium-233, corresponding to the decay into the ground and isomer state, allows to measure the isomer transition energy without additional theoretical input parameters and increase the energy accuracy. We study the dependence of the attainable precision of this measurement on the signal and background count rates and the instrumental energy resolution. Assuming realistic experimental parameters corresponding to the currently available detector technology, we show that such a measurement is highly feasable.

  7. The sim operon facilitates the transport and metabolism of sucrose isomers in Lactobacillus casei ATCC 334. (United States)

    Thompson, John; Jakubovics, Nicholas; Abraham, Bindu; Hess, Sonja; Pikis, Andreas


    Inspection of the genome sequence of Lactobacillus casei ATCC 334 revealed two operons that might dissimilate the five isomers of sucrose. To test this hypothesis, cells of L. casei ATCC 334 were grown in a defined medium supplemented with various sugars, including each of the five isomeric disaccharides. Extracts prepared from cells grown on the sucrose isomers contained high levels of two polypeptides with M(r)s of approximately 50,000 and approximately 17,500. Neither protein was present in cells grown on glucose, maltose or sucrose. Proteomic, enzymatic, and Western blot analyses identified the approximately 50-kDa protein as an NAD(+)- and metal ion-dependent phospho-alpha-glucosidase. The oligomeric enzyme was purified, and a catalytic mechanism is proposed. The smaller polypeptide represented an EIIA component of the phosphoenolpyruvate-dependent sugar phosphotransferase system. Phospho-alpha-glucosidase and EIIA are encoded by genes at the LSEI_0369 (simA) and LSEI_0374 (simF) loci, respectively, in a block of seven genes comprising the sucrose isomer metabolism (sim) operon. Northern blot analyses provided evidence that three mRNA transcripts were up-regulated during logarithmic growth of L. casei ATCC 334 on sucrose isomers. Internal simA and simF gene probes hybridized to approximately 1.5- and approximately 1.3-kb transcripts, respectively. A 6.8-kb mRNA transcript was detected by both probes, which was indicative of cotranscription of the entire sim operon.

  8. Comparative dielectric study of pentanol isomers with terahertz time-domain spectroscopy (United States)

    Yomogida, Yoshiki; Sato, Yuki; Yamakawa, Kazuyoshi; Nozaki, Ryusuke; Mishina, Tomobumi; Nakahara, Jun'ichiro


    Using terahertz (THz) time-domain spectroscopy, we have measured the complex permittivity of seven pentanol isomers (1-pentanol, 2-pentanol, 3-pentanol, 2-methly-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, and 3-methyl-2-butanol) in the frequency range of 0.2-2.5 THz at temperatures from 253 to 323 K. For all samples, the complex permittivity contains the following three components: (i) a high-frequency side of dielectric relaxation processes, (ii) a broad vibration mode around 1.5 THz, and (iii) a low-frequency side of an intermolecular stretching mode located above 2.5 THz. At low temperatures, the relaxation process moves to a low-frequency range and a peak of the broad vibration mode, which is independent of temperature, is clearly observed around 1.5 THz. Spectra in the THz region change sensitively according to the molecular structure of the pentanol isomers. We have also observed the complex permittivity in the microwave range of 1 MHz-20 GHz. The behavior of the dielectric relaxation processes below GHz region much depend on the isomers. Our experimental data demonstrate that the molecular structures of the pentanol isomers influence all the molecular dynamics ranging from dielectric relaxation phenomena, which are due to reorientational motion of the molecules, to vibration dynamics within the hydrogen-bonded network structure.

  9. Variations of structures and solid-state conductivity of isomeric silver(I) coordination polymers having linear and V-shaped thiophene-centered ditriazole ligands

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Bin [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); School of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang, 330063 (China); Geng, Jiao; Zhang, Lie [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Huang, Wei, E-mail: [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)


    A pair of new linear and V-shaped acceptor–donor–acceptor (A−D−A) thiophene-centered ditriazole structural isomers, i.e., 2,5-di(1H-1,2,4-triazol-1-yl)thiophene (L{sup 1}) and 3,4-di(1H-1,2,4-triazol-1-yl)thiophene (L{sup 2}), has been synthesized and characterized. They are used as μ{sub 2}-bridging ligands to prepare a pair of silver(I) coordination polymers formulated as [Ag(L{sup 1})(NO{sub 3})]{sub n} (1) and [Ag(L{sup 2})(NO{sub 3})]{sub n} (2), which are also structural isomers at the supramolecular level. X-ray single-crystal diffraction analyses for 1 and 2 reveal that they exhibit the same one-dimensional (1D) coordination polymers but different structural architectures because of the distinguishable shape and configuration of isomeric ligands (L{sup 1} and L{sup 2}) and the alterations of the coordination numbers. More interestingly, compared with the free ligands, 1D silver(I) polymeric isomers 1 and 2 show significant enhancement of solid-state conductivity to different extents (1.42×10{sup 4} and 2.17×10{sup 3} times), where 6.96 times' enhancement of solid-state conductivity from 1 to 2 has been observed. The formation of Ag–N coordinative bonds and the configurational discrepancy of L{sup 1} and L{sup 2} are believed to play important roles in facilitating the electron transport between molecules, which can also be supported by Density Function Theory calculations of their band gaps. - Graphical abstract: A pair of linear and V-shaped isomeric thiophene-centered ditriazole ligands (L{sup 1}) and L{sup 2} are used to prepare a pair of silver(I) polymeric isomers (1 and 2), where significant enhancement of solid-state conductivity to different extents are observed originating from the distinguishable shape and configuration of isomeric ligands. - Highlights: • A pair of linear and V-shaped thiophene-centered ditriazole structural isomers is prepared. • They are used as µ{sub 2}-bridging ligands to prepare a pair of silver

  10. Probing ground and low-lying excited states for HIO{sub 2} isomers

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Gabriel L. C. de [Departamento de Química, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso 78060-900 (Brazil); Instituto de Ciências Exatas e Tecnologia, Universidade Federal do Amazonas, Itacoatiara, Amazonas 69100-000 (Brazil); Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2 (Canada); Brown, Alex, E-mail: [Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2 (Canada)


    We present a computational study on HIO{sub 2} molecules. Ground state properties such as equilibrium structures, relative energetics, vibrational frequencies, and infrared intensities were obtained for all the isomers at the coupled-cluster with single and double excitations as well as perturbative inclusion of triples (CCSD(T)) level of theory with the aug-cc-pVTZ-PP basis set and ECP-28-PP effective core potential for iodine and the aug-cc-pVTZ basis set for hydrogen and oxygen atoms. The HOIO structure is confirmed as the lowest energy isomer. The relative energies are shown to be HOIO < HOOI < HI(O)O. The HO(O)I isomer is only stable at the density functional theory (DFT) level of theory. The transition states determined show interconversion of the isomers is possible. In order to facilitate future experimental identification, vibrational frequencies are also determined for all corresponding deuterated species. Vertical excitation energies for the three lowest-lying singlet and triplet excited states were determined using the configuration interaction singles, time-dependent density functional theory (TD-DFT)/B3LYP, TD-DFT/G96PW91, and equation of motion-CCSD approaches with the LANL2DZ basis set plus effective core potential for iodine and the aug-cc-pVTZ basis set for hydrogen and oxygen atoms. It is shown that HOIO and HOOI isomers have excited states accessible at solar wavelengths (<4.0 eV) but these states have very small oscillator strengths (<2 × 10{sup −3})

  11. Conformational preferences and synthesis of isomers Z and E of oxazole-dehydrophenylalanine. (United States)

    Staś, Monika; Bujak, Maciej; Broda, Małgorzata A; Siodłak, Dawid


    Dehydrophenylalanine, ΔPhe, is the most commonly studied α,β-dehydroamino acid. In nature, further modifications of the α,β-dehydroamino acids were found, for example, replacement of the C-terminal amide group by oxazole ring. The conformational properties of oxazole-dehydrophenylalanine residue (ΔPhe-Ozl), both isomers Z and E, were investigated. To determine all possible conformations, theoretical calculations were performed using Ac-(Z/E)-ΔPhe-Ozl(4-Me) model compounds at M06-2X/6-31++G(d,p) level of theory. Ac-(Z/E)-ΔPhe-Ozl-4-COOEt compounds were synthesized and the conformational preferences of each isomer, Z and E, were investigated using FTIR and NMR-NOE in solutions of increasing polarity (CHCl3 , DMSO-d6). The solid-state low-temperature structures of Ac-(Z)-ΔPhe-Ozl-4-COOEt and its intermediate analog Ac-(Z)-ΔPhe-Ozn(4-OH)-4-COOEt were also determined. In a weakly polar environment, the ΔPhe-Ozl residue has a tendency to adopt the conformation β2 with the calculated φ and ψ angles of -127° and 0° for the isomer Z and -170° and 26° for the isomer E. The increase of environment polarity favors the helical conformation α and the beta-turn like conformation β, but the conformation β2 seems to be still accessible. The (E)-ΔPhe-Ozl residue can be obtained from the isomer Z in photoisomerization reaction. However, hydroxyl-oxazoline-dehydrophenylalanine ΔPhe-Ozn(4-OH) decomposes in such conditions. Alternatively, (E)-ΔPhe-NH2 can be applied as a substrate in the Hantzsch reaction. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 283-294, 2016.

  12. Portable, Battery Operated Capillary Electrophoresis with Optical Isomer Resolution Integrated with Ionization Source for Mass Spectrometry (United States)

    Moini, Mehdi; Rollman, Christopher M.


    We introduce a battery operated capillary electrophoresis electrospray ionization (CE/ESI) source for mass spectrometry with optical isomer separation capability. The source fits in front of low or high resolution mass spectrometers similar to a nanospray source with about the same weight and size. The source has two high voltage power supplies (±25 kV HVPS) capable of operating in forward or reverse polarity modes and powered by a 12 V rechargeable lithium ion battery with operation time of ~10 h. In ultrafast CE mode, in which short narrow capillaries (≤15 μm i.d., 15-25 cm long) and field gradients ≥1000 V/cm are used, peak widths at the base are <1 s wide. Under these conditions, the source provides high resolution separation, including optical isomer resolution in ~1 min. Using a low resolution mass spectrometer (LTQ Velos) with a scan time of 0.07 s/scan, baseline separation of amino acids and their optical isomers were achieved in ~1 min. Moreover, bovine serum albumin (BSA) was analyzed in ~1 min with 56% coverage using the data-dependent MS/MS. Using a high resolution mass spectrometer (Thermo Orbitrap Elite) with 15,000 resolution, the fastest scan time achieved was 0.15 s, which was adequate for CE-MS analysis when optical isomer separation is not required or when the optical isomers were well separated. Figures of merit including a detection limit of 2 fmol and linear dynamic range of two orders of magnitude were achieved for amino acids.

  13. Probing ground and low-lying excited states for HIO2 isomers (United States)

    de Souza, Gabriel L. C.; Brown, Alex


    We present a computational study on HIO2 molecules. Ground state properties such as equilibrium structures, relative energetics, vibrational frequencies, and infrared intensities were obtained for all the isomers at the coupled-cluster with single and double excitations as well as perturbative inclusion of triples (CCSD(T)) level of theory with the aug-cc-pVTZ-PP basis set and ECP-28-PP effective core potential for iodine and the aug-cc-pVTZ basis set for hydrogen and oxygen atoms. The HOIO structure is confirmed as the lowest energy isomer. The relative energies are shown to be HOIO < HOOI < HI(O)O. The HO(O)I isomer is only stable at the density functional theory (DFT) level of theory. The transition states determined show interconversion of the isomers is possible. In order to facilitate future experimental identification, vibrational frequencies are also determined for all corresponding deuterated species. Vertical excitation energies for the three lowest-lying singlet and triplet excited states were determined using the configuration interaction singles, time-dependent density functional theory (TD-DFT)/B3LYP, TD-DFT/G96PW91, and equation of motion-CCSD approaches with the LANL2DZ basis set plus effective core potential for iodine and the aug-cc-pVTZ basis set for hydrogen and oxygen atoms. It is shown that HOIO and HOOI isomers have excited states accessible at solar wavelengths (<4.0 eV) but these states have very small oscillator strengths (<2 × 10-3).

  14. An experimental and kinetic modeling study of the oxidation of the four isomers of butanol. (United States)

    Moss, Jeffrey T; Berkowitz, Andrew M; Oehlschlaeger, Matthew A; Biet, Joffrey; Warth, Valérie; Glaude, Pierre-Alexandre; Battin-Leclerc, Frédérique


    Butanol, an alcohol which can be produced from biomass sources, has received recent interest as an alternative to gasoline for use in spark ignition engines and as a possible blending compound with fossil diesel or biodiesel. Therefore, the autoignition of the four isomers of butanol (1-butanol, 2-butanol, iso-butanol, and tert-butanol) has been experimentally studied at high temperatures in a shock tube, and a kinetic mechanism for description of their high-temperature oxidation has been developed. Ignition delay times for butanol/oxygen/argon mixtures have been measured behind reflected shock waves at temperatures and pressures ranging from approximately 1200 to 1800 K and 1 to 4 bar. Electronically excited OH emission and pressure measurements were used to determine ignition-delay times. The influence of temperature, pressure, and mixture composition on ignition delay has been characterized. A detailed kinetic mechanism has been developed to describe the oxidation of the butanol isomers and validated by comparison to the shock-tube measurements. Reaction flux and sensitivity analysis illustrates the relative importance of the three competing classes of consumption reactions during the oxidation of the four butanol isomers: dehydration, unimolecular decomposition, and H-atom abstraction. Kinetic modeling indicates that the consumption of 1-butanol and iso-butanol, the most reactive isomers, takes place primarily by H-atom abstraction resulting in the formation of radicals, the decomposition of which yields highly reactive branching agents, H atoms and OH radicals. Conversely, the consumption of tert-butanol and 2-butanol, the least reactive isomers, takes place primarily via dehydration, resulting in the formation of alkenes, which lead to resonance stabilized radicals with very low reactivity. To our knowledge, the ignition-delay measurements and oxidation mechanism presented here for 2-butanol, iso-butanol, and tert-butanol are the first of their kind.

  15. Heroin discriminative stimulus effects of methadone, LAAM and other isomers of acetylmethadol in rats. (United States)

    Newman, Jennifer L; Vann, Robert E; May, Everette L; Beardsley, Patrick M


    LAAM (alpha- l-acetylmethadol) is a derivative of the synthetic mu-opiate agonist methadone and is one of the four isomers of acetylmethadol. Methadone and LAAM have similar pharmacological properties and both are approved medications for the treatment of heroin dependency disorders. Few studies have reported on the pharmacology of acetylmethadol's other isomers and most of these have focused on their potential analgesic activity. The purpose of the present investigation was to examine the discriminative stimulus effects of LAAM, the other isomers of acetylmethadol, and methadone in rats trained to discriminate heroin from water, and to compare the duration of the discriminative stimulus effects of heroin, methadone, and LAAM. Long-Evans rats were trained to discriminate 0.3 mg/kg heroin from water under a fixed ratio 10 (FR10) schedule of food reinforcement. Dose-response functions for heroin, methadone, LAAM, three other isomers of acetylmethadol: alpha- d-acetylmethadol, beta- d-acetylmethadol, beta- l-acetylmethadol, and its precursor, beta- l-methadol were examined. Additionally, the time course effects for heroin, methadone, and LAAM were examined. LAAM and methadone dose-dependently occasioned heroin-like discriminative stimulus effects. Two of acetylmethadol's isomers, alpha- d-acetylmethadol and beta- d-acetylmethadol, were more potent than LAAM in producing heroin-like effects. The beta- l-methadol precursor and beta- l-acetylmethadol did not fully substitute for heroin's discriminative stimulus. LAAM elicited heroin-like discriminative stimulus effects for at least 6 h and generated partial generalization up to 36 h following administration. Methadone, LAAM, beta- d-acetylmethadol and alpha- d-acetylmethadol, but not beta- l-acetylmethadol and beta- l-methadol evoke heroin-like discriminative stimulus effects.

  16. Insight into and Computational Studies of the Selective Synthesis of 6H-Dibenzo[b,h]xanthenes. (United States)

    Carneiro, Paula F; Pinto, Maria do Carmo F R; Marra, Roberta K F; Campos, Vinícius R; Resende, Jackson Antônio L C; Delarmelina, Maicon; Carneiro, José Walkimar M; Lima, Emerson S; da Silva, Fernando de C; Ferreira, Vitor F


    Starting from 2-hydroxy-1,4-naphthoquinone (lawsone), we synthesized eight new 6H-dibenzo[b,h]xanthene derivatives selectively under solvent-free conditions. Spectroscopic investigations confirmed that only the isomer 6H-dibenzo[b,h]xanthene was obtained in all eight cases. Computational studies provide a rationalization for the selective appearance of these isomers having as an intermediate an addition product.

  17. Symmetric two-coordinate photodiode

    Directory of Open Access Journals (Sweden)

    Dobrovolskiy Yu. G.


    Full Text Available The two-coordinate photodiode is developed and explored on the longitudinal photoeffect, which allows to get the coordinate descriptions symmetric on the steepness and longitudinal resistance great exactness. It was shown, that the best type of the coordinate description is observed in the case of scanning by the optical probe on the central part of the photosensitive element. The ways of improvement of steepness and linear of its coordinate description were analyzed.

  18. Invariant Manifolds and Collective Coordinates

    CERN Document Server

    Papenbrock, T


    We introduce suitable coordinate systems for interacting many-body systems with invariant manifolds. These are Cartesian in coordinate and momentum space and chosen such that several components are identically zero for motion on the invariant manifold. In this sense these coordinates are collective. We make a connection to Zickendraht's collective coordinates and present certain configurations of few-body systems where rotations and vibrations decouple from single-particle motion. These configurations do not depend on details of the interaction.

  19. Coordination Processes in International Organisations

    DEFF Research Database (Denmark)

    Nedergaard, Peter


    to coordinate relatively elaborate agreements due to the strength of its coordination as far as professional or technical and political activities (excepting the ILO budget) are concerned. In other more clear-cut or 'simple' policy areas such as the ILO budget, the EU coordination is weak: this contrast...

  20. Work Coordination Engine (United States)

    Zendejas, Silvino; Bui, Tung; Bui, Bach; Malhotra, Shantanu; Chen, Fannie; Kim, Rachel; Allen, Christopher; Luong, Ivy; Chang, George; Sadaqathulla, Syed


    The Work Coordination Engine (WCE) is a Java application integrated into the Service Management Database (SMDB), which coordinates the dispatching and monitoring of a work order system. WCE de-queues work orders from SMDB and orchestrates the dispatching of work to a registered set of software worker applications distributed over a set of local, or remote, heterogeneous computing systems. WCE monitors the execution of work orders once dispatched, and accepts the results of the work order by storing to the SMDB persistent store. The software leverages the use of a relational database, Java Messaging System (JMS), and Web Services using Simple Object Access Protocol (SOAP) technologies to implement an efficient work-order dispatching mechanism capable of coordinating the work of multiple computer servers on various platforms working concurrently on different, or similar, types of data or algorithmic processing. Existing (legacy) applications can be wrapped with a proxy object so that no changes to the application are needed to make them available for integration into the work order system as "workers." WCE automatically reschedules work orders that fail to be executed by one server to a different server if available. From initiation to completion, the system manages the execution state of work orders and workers via a well-defined set of events, states, and actions. It allows for configurable work-order execution timeouts by work-order type. This innovation eliminates a current processing bottleneck by providing a highly scalable, distributed work-order system used to quickly generate products needed by the Deep Space Network (DSN) to support space flight operations. WCE is driven by asynchronous messages delivered via JMS indicating the availability of new work or workers. It runs completely unattended in support of the lights-out operations concept in the DSN.

  1. Advice for Coordination

    DEFF Research Database (Denmark)

    Hankin, Chris; Nielson, Flemming; Nielson, Hanne Riis


    demanding than the closed joinpoints in more traditional aspect oriented languages like AspectJ. The usefulness of our approach is demonstrated by mechanisms for discretionary and mandatory access control policies, as usually expressed by reference monitors, as well as mechanisms for logging actions.......We show how to extend a coordination language with support for aspect oriented programming. The main challenge is how to properly deal with the trapping of actions before the actual data have been bound to the formal parameters. This necessitates dealing with open joinpoints – which is more...

  2. Markov stochasticity coordinates (United States)

    Eliazar, Iddo


    Markov dynamics constitute one of the most fundamental models of random motion between the states of a system of interest. Markov dynamics have diverse applications in many fields of science and engineering, and are particularly applicable in the context of random motion in networks. In this paper we present a two-dimensional gauging method of the randomness of Markov dynamics. The method-termed Markov Stochasticity Coordinates-is established, discussed, and exemplified. Also, the method is tweaked to quantify the stochasticity of the first-passage-times of Markov dynamics, and the socioeconomic equality and mobility in human societies.

  3. 丁醛异构物塔产品结构的优化研究%Research on Product Mix Optimization of Butyraldehyde Isomer Column

    Institute of Scientific and Technical Information of China (English)

    李云辉; 李治水; 聂增来; 王海; 窦秀桂; 邹华斌; 王松


    以天津渤化永利化工股份有限公司#1丁辛醇装置中丁醛异构物塔的产品结构优化为研究目标,利用Aspen Plus 软件对丁醛异构物塔进行流程模拟计算,根据计算结果对丁醛异构物塔的进料口、工艺管线等进行了优化改造,并对其操作参数进行了调整.重新开车后,丁醛异构物塔塔顶异丁醛产品纯度达到 99%,以上,塔釜正丁醛纯度在 99.4%,以上(其中异丁醛含量小于 0.1%,),满足下游辛醇工艺标准要求.由此,实现了选择性生产异丁醛与异丁醇的目标.%This study aims to optimize the product mix of butyraldehyde isomer column in #1 butyloctanol unit of Tianjin BohuaYongli Chemical Industry Co., Ltd. Process simulation of the butyraldehyde isomer column was conducted using As-pen Plus. Then, technique modifications to the feed stage and the process pipeline of the butanol isomer column were carried out, and operating parameters of the column were also optimized. When the column restarted, the purity of isobutyraldehyde and n-butyraldehyde reached above 99% and 99.4% respectively. Furthermore, the content of isobutyraldehydein the n-butyraldehyde was less than 0.1%, which meets the requirements of the downstream octanol unit. Therefore, the aim of selec-tive production of isobutanol and isobutyraldehyde was achieved.

  4. 论价值差异协同的现实意义及其路径选择%On Practical Significance of Coordination of Value Differences and Path Selection

    Institute of Scientific and Technical Information of China (English)



    Value is an important foundation of human existence.It is an indisputable fact that there is a pluralist value at present time. Different value subjects have different evaluation criteria in treating their value objects based on their own interests.So value difference is generated.Value differences do not eternally exist.In specific social and historical conditions, based on people’ s common interests and common nature, the value difference can be coordinated.Collaboration of value difference has very important practical significance in the personal, national and international relations of different value subjects, but the coordination path must respect the differences and also seek the consensus.%价值是人类生存的重要根基,当下呈现出的价值多元已是不争的事实,不同的价值主体在各自的利益基础上对待价值客体会呈现出不同的评价标准和价值取向,产生价值差异。价值差异并不是永恒存在的,在特定的社会历史条件下,基于主体存在利益共同性、人的“类”本质和人性角度考虑,价值差异具有协同的可能性,价值差异的协同使得价值主体与价值异己者在人际、族际和国际关系处理上具有极为重要的现实意义,其协同路径既要尊重差异,也要寻求共识。

  5. Anatomy of phobanes. diastereoselective synthesis of the three isomers of n-butylphobane and a comparison of their donor properties. (United States)

    Carreira, Monica; Charernsuk, Manutsavin; Eberhard, Michael; Fey, Natalie; van Ginkel, Roel; Hamilton, Alex; Mul, Wilhelmus P; Orpen, A Guy; Phetmung, Hirihataya; Pringle, Paul G


    Three methods for the large scale (50-100 g) separation of the secondary phobanes 9-phosphabicyclo[3.3.1]nonane (s-PhobPH) and 9-phosphabicyclo[4.2.1]nonane (a-PhobPH) are described in detail. Selective protonation of s-PhobPH with aqueous HCl in the presence of a-PhobPH is an efficient way to obtain large quantities of a-PhobPH. Selective oxidation of a-PhobPH in an acidified mixture of a-PhobPH and s-PhobPH is an efficient way to obtain large quantities of s-PhobPH. The crystalline, air-stable phosphonium salts [s-PhobP(CH(2)OH)(2)]Cl and [a-PhobP(CH(2)OH)(2)]Cl can be separated by a selective deformylation with aqueous NaOH. a-PhobPH is shown to be a(5)-PhobPH in which the H lies over the five-membered ring. The isomeric a(7)-PhobPH has been detected but isomerizes to a(5)-PhobPH rapidly in the presence of water. s-PhobPH is more basic than a-PhobPH by about 2 pK(a) units in MeOH. Treatment of s-PhobPH with BH(3).THF gives s-PhobPH(BH(3)) and similarly a-PhobPH gives a(5)-PhobPH(BH(3)). Isomerically pure s-PhobPCl and a(5)-PhobPCl are prepared by reaction of the corresponding PhobPH with C(2)Cl(6). The n-butyl phobane s-PhobPBu is prepared by nucleophilic (using s-PhobPH or s-PhobPLi) and electrophilic (using s-PhobPCl) routes. Isomerically pure a(5)-PhobPBu is prepared by treatment of a-PhobPLi with (n)BuBr and a(7)-PhobPBu is prepared by quaternization of a-PhobPH with (n)BuBr followed by deprotonation. From the rates of conversion of a(7)-PhobPBu to a(5)-PhobPBu, the DeltaG(double dagger) (403 K) for P-inversion is calculated to be 38.1 kcal mol(-1) (160 kJ mol(-1)). The donor properties of the individual isomers of PhobPBu were assessed from the following spectroscopic measurements: (i) (1)J(PSe) for PhobP(Se)Bu; (ii) nu(CO) for trans-[RhCl(CO)(PhobPBu)(2)], (iii) (1)J(PtP) for the PEt(3) in trans-[PtCl(2)(PEt(3))(PhobPBu)]. In each case, the data are consistent with the order of sigma-donation being a(7)-PhobPBu > s-PhobPBu > a(5)-PhobPBu. This same order

  6. Preferential alkali metal adduct formation by cis geometrical isomers of dicaffeoylquinic acids allows for efficient discrimination from their trans isomers during ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry

    CSIR Research Space (South Africa)

    Makola, MM


    Full Text Available to differentiate under normal MS settings. Keywords: Chlorogenic acids, geometrical isomers, fragmentation, sodium adduct, QTOF- MS, Cone voltage. Rapid Communications in Mass Spectrometry 3 INTRODUCTION Caffeoylquinic acid (CQA) derivatives...-H-162]- was much more intense than that of the sodium adduct at m/z 375.065. [28] Between the cis isomers, the cis-cis isomer was observed to form more of the sodium adduct (m/z 375.065) relative to the deprotonated caffeoylquinic acid fragment (m...

  7. High-Throughput Analysis of Methylmalonic Acid in Serum, Plasma, and Urine by LC-MS/MS. Method for Analyzing Isomers Without Chromatographic Separation. (United States)

    Kushnir, Mark M; Nelson, Gordon J; Frank, Elizabeth L; Rockwood, Alan L


    Measurement of methylmalonic acid (MMA) plays an important role in the diagnosis of vitamin B12 deficiency. Vitamin B12 is an essential cofactor for the enzymatic carbon rearrangement of methylmalonyl-CoA (MMA-CoA) to succinyl-CoA (SA-CoA), and the lack of vitamin B12 leads to elevated concentrations of MMA. Presence of succinic acid (SA) complicates the analysis because mass spectra of MMA and SA are indistinguishable, when analyzed in negative ion mode and the peaks are difficult to resolve chromatographically. We developed a method for the selective analysis of MMA that exploits the significant difference in fragmentation patterns of di-butyl derivatives of the isomers MMA and SA in a tandem mass spectrometer when analyzed in positive ion mode. Tandem mass spectra of di-butyl derivatives of MMA and SA are very distinct; this allows selective analysis of MMA in the presence of SA. The instrumental analysis is performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive ion mode, which is, in combination with selective extraction of acidic compounds, is highly selective for organic acids with multiple carboxyl groups (dicarboxylic, tricarboxylic, etc.). In this method organic acids with a single carboxyl group are virtually undetectable in the mass spectrometer; the only organic acid, other than MMA, that is detected by this method is its isomer, SA. Quantitative measurement of MMA in this method is performed using a deconvolution algorithm, which mathematically resolves the signal corresponding to MMA and does not require chromatographic resolution of the MMA and SA peaks. Because of its high selectivity, the method utilizes isocratic chromatographic separation; reconditioning and re-equilibration of the chromatographic column between injections is unnecessary. The above features of the method allow high-throughput analysis of MMA with analysis cycle time of 1 min.

  8. Trolox equivalent antioxidant capacity of different geometrical isomers of alpha-carotene, beta-carotene, lycopene, and zeaxanthin. (United States)

    Böhm, Volker; Puspitasari-Nienaber, Ni Luh; Ferruzzi, Mario G; Schwartz, Steven J


    Isomerization of carotenoids, which is often encountered in food processing under the influence of temperature and light, may play a role in the observed protective effects of this group of secondary plant products. Investigation of in vitro antioxidant activity of prominent carotenoid geometrical isomers was undertaken in light of recent reports illustrating a large percentage of carotenoid (Z)-isomers in biological fluids and tissues. Alpha-carotene, beta-carotene, lycopene, and zeaxanthin were isolated from foods or supplements and subsequently photoisomerized with iodine as a catalyst. Major Z-isomers of each carotenoid were fractionated by semipreparative C(30) HPLC. In vitro antioxidant activity of all isomers collected was measured photometrically using the Trolox equivalent antioxidant capacity (TEAC) assay. TEAC values of 17 geometrical isomers investigated ranged from 0.5 to 3.1 mmol/L. Three unidentified (Z)-isomers of lycopene showed the highest antioxidant activity, being significantly higher than the result for (all-E)-lycopene, which had approximately two times the activity of (all-E)-beta-carotene. On the other hand, (9Z)-zeaxanthin had a more than 80% lower TEAC value compared to that of (all-E)-lycopene. These results allow for the in vivo relevance of (Z)-isomers of carotenoids to be considered.

  9. Selective endo and exo binding of mono- and ditopic ligands to a rhomboidal diporphyrin prism. (United States)

    Jayamurugan, Govindasamy; Roberts, Derrick A; Ronson, Tanya K; Nitschke, Jonathan R


    Copper(I) can preferentially form heteroleptic complexes containing two phosphine and two nitrogen donors due to steric factors. This preference was employed to direct the self-assembly of a porphyrin-faced rhomboidal prism having two parallel tetrakis(4-iminopyridyl)porphyrinatozinc(II) faces linked by eight 1,4-bis(diphenylphosphino)benzene pillars. The coordination preferences of the Cu(I) ions and geometries of the ligands come together to generate a slipped-cofacial orientation of the porphyrinatozinc(II) faces. This orientation enables selective encapsulation of 3,3'-bipyridine (bipy), which bridges the Zn(II) ions of the parallel porphyrins, whereas 4,4'-bipy exhibits weaker external coordination to the porphyrin faces. Reaction with 2,2'-bipy, by contrast, results in the displacement of the tetratopic porphyrin ligand and formation of [{(2,2'-bipy)Cu(I) }2 (diphosphine)2 ]. The differing strengths of interactions of bipyridine isomers with the system allows for a hierarchy to be deciphered, whereby 4,4'-bipy may be displaced by 3,3'-bipy, which in turn is displaced by 2,2'-bipy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Analysis of histidine and urocanic acid isomers by reversed-phase high-performance liquid chromatography. (United States)

    Hermann, K; Abeck, D


    The qualitative separation performance of a C18, C8 and C4 reversed-phase column was investigated for the separation of histidine and its metabolites histamine, 1-methyihistamine and trans- and cis-urocanic acid. Trans- and cis-urocanic acid were baseline separated from their precursor histidine on all three columns using isocratic elution with a mobile phase composed of 0.01 M aqueous TEAP pH 3.0 and acetonitrile at a ratio of 98:2 (v/v). However, histidine was not separated from histamine and 1-methyihistamine. Selecting the C8 column and introducing 0.005 M of the ion pairing reagent 1-octanesulfonic acid sodium salt into the aqueous solution and acetonitrile at a ratio of 90:10 (v/v), significantly improved the separation. The separation was also followed by a change in the retention times and the order of elution. The sequence of elution was histidine, cis-urocanic acid, trans-urocanic acid, histamine and 1-methylhistamine with retention times of 5.58 +/- 0.07, 7.03 +/- 0.15, 7.92 +/- 0.18, 18.77 +/- 0.24 and 20.79 +/- 0.21 min (mean +/- SD; n=5). The separation on the C8 column in the presence of the ion-pairing reagent was further improved with gradient elution that resulted in a reduction in the retention times and elution volumes of histamine and 1-methylhistamine. The detection limits of histidine and trans-urocanic acid at a wavelength of 210 nm and an injection volume of 0.05 ml were 5 x 10(-8) mol l(-1) (n=3). The kinetic of the in-vitro conversion of trans- into the cis-isomer after UV irradiation was depending on the time of exposure and the energy of the light source. UVB light induced a significantly faster conversion than UVA light. TUCA and cUCA samples kept at -25 degrees C were stable for up to 50 weeks. Samples, eluted from human skin showed various concentrations of histidine and trans- and cis-urocanic acid with an average of 1.69 +/- 0.33 x 10(-5) mol l(-1), 1.17 +/- 0.43 x 10(-5) mol l(-1) and 1.67 +/- 0.33 x 10(-5) mol l(-1), respectively

  11. Coordination Processes in International Organisations

    DEFF Research Database (Denmark)

    Nedergaard, Peter


    The EU is not a member of the International Labour Organisation (ILO), but relatively elaborate EU coordination takes place anyway. This paper addresses two research questions: 1) How is it possible to evaluate the coordination of the EU in its specific observable configuration in the ILO?, and 2......) To what outcome does this coordination lead and why? Based on an analysis of EU coordination before and during the International Labour Conference in 2005, and on a comparison with coordination processes of the IMEC group, it is found that the Commission and the Presidency act as twin-agents vis...... by the principals. On the other hand, both before and during the Conference, the Member States accept the so-called discursive coordination of the Commission, which seems to be of great (but often neglected) importance. Owing to the organisational set-up in which coordination takes place, the EU is able...

  12. Assessment of the in vivo genotoxicity of isomers of dinitrotoluene using the alkaline Comet and peripheral blood micronucleus assays. (United States)

    Lent, Emily May; Crouse, Lee C B; Quinn, Michael J; Wallace, Shannon M


    Dinitrotoluene (DNT) is a nitroaromatic explosive that exists as six isomers; two major isomers (2,4- and 2,6-DNT) and four minor isomers (2,3-, 2,5-, 3,4-, and 3,5-DNT). DNT has been found in soil, surface water, and groundwater near ammunition production plants. The major isomers of DNT are classified as "likely to cause cancer in humans."In vitro studies have provided conflicting data regarding the genotoxicity of the minor isomers. Studies indicate that metabolism in the gut and liver are necessary to convert DNT to genotoxic compounds. As such, in the present study the genotoxicity of isomers of DNT was assessed using two in vivo genotoxicity assays. The Comet assay was used to detect DNA damage in liver cells from male Sprague-Dawley rats following oral exposure (14-day) to individual isomers of DNT. The micronucleus assay was conducted using flow cytometric analysis to detect chromosomal damage in peripheral blood. Treatment with 2,3-, 3,4-, 2,4-, 2,5- and 3,5-DNT did not induce DNA damage in liver cells or increase the frequency of micronucleated reticulocytes (MN-RET) in peripheral blood at the doses tested. Treatment with 2,6-DNT induced DNA damage in liver tissue at all doses tested, but did not increase the frequency of micronucleated reticulocytes (MN-RET) in peripheral blood. Thus, 2,4-DNT and the minor isomers were not genotoxic under these test conditions, while 2,6-DNT was genotoxic in the target tissue, the liver. These results support previous research which indicated that the hepatocarcinogenicity of technical grade DNT (TG-DNT) could be attributed to the 2,6-DNT isomer. Published by Elsevier B.V.

  13. Isomer and β-decay spectroscopy of Tz=1 isotopes below the N=Z=50 shell gap (United States)

    Boutachkov, P.; Braun, N.; Brock, T.; Nara Singh, B. S.; Blazhev, A.; Liu, Z.; Wadsworth, R.; Górska, M.; Grawe, H.; Pietri, S.; Domingo-Pardo, C.; Faestermann, T.; Farinon, F.; Grebosz, J.; Kojuharov, I.; Kurz, N.; Nociforo, C.; Podolyák, Zs; Prochazka, A.; Steer, S.; Cáceres, L.; Engert, T.; Gerl, J.; Goel, N.; Hoischen, R.; Schaffner, H.; Weick, H.; Wollersheim, H.-J.; Bettermann, L.; Finke, F.; Geibel, K.; Ilie, G.; Iwasaki, H.; Jolie, J.; Nyberg, J.; Reiter, P.; Scholl, C.; Söderström, P.-A.; Warr, N.; Eppinger, K.; Gottardo, A.; Hinke, C.; Krücken, R.; Pfützner, M.; Regan, P.; Rinta-Antila, S.; Rudolph, D.; Woods, P.; Ataç, A.; Merchán, E.


    The RISING setup at the GSI-FRS facility was used to investigate the isomer and beta decays in N~Z~50 Cd, Ag and Pd isotopes. A preliminary analysis of the data has revealed new results on the Tz=1, 94Pd, 96Ag and 98Cd isotopes. In 94Pd a new high-spin isomer was observed, whilst in 96Ag 3 new isomeric states were identified, including core-excited states. In 98Cd a new high-energy isomeric γ-ray transition is observed, thus enabling us to confirm the previous spin assignment for the core-excited 12+ isomer.

  14. Coordination using Implicit Communication

    CERN Document Server

    Cuff, Paul


    We explore a basic noise-free signaling scenario where coordination and communication are naturally merged. A random signal X_1,...,X_n is processed to produce a control signal or action sequence A_1,...,A_n, which is observed and further processed (without access to X_1,...,X_n) to produce a third sequence B_1,...,B_n. The object of interest is the set of empirical joint distributions p(x,a,b) that can be achieved in this setting. We show that H(A) >= I(X;A,B) is the necessary and sufficient condition for achieving p(x,a,b) when no causality constraints are enforced on the encoders. We also give results for various causality constraints. This setting sheds light on the embedding of digital information in analog signals, a concept that is exploited in digital watermarking, steganography, cooperative communication, and strategic play in team games such as bridge.

  15. On Coordinating Collaborative Objects

    CERN Document Server

    Imine, Abdessamad


    A collaborative object represents a data type (such as a text document) designed to be shared by a group of dispersed users. The Operational Transformation (OT) is a coordination approach used for supporting optimistic replication for these objects. It allows the users to concurrently update the shared data and exchange their updates in any order since the convergence of all replicas, i.e. the fact that all users view the same data, is ensured in all cases. However, designing algorithms for achieving convergence with the OT approach is a critical and challenging issue. In this paper, we propose a formal compositional method for specifying complex collaborative objects. The most important feature of our method is that designing an OT algorithm for the composed collaborative object can be done by reusing the OT algorithms of component collaborative objects. By using our method, we can start from correct small collaborative objects which are relatively easy to handle and incrementally combine them to build more ...

  16. Control of the mutual arrangement of cyclometalated ligands in cationic iridium(III) complexes. Synthesis, spectroscopy, and electroluminescence of the different isomers. (United States)

    Fernández-Hernández, Jesús M; Yang, Cheng-Han; Beltrán, Juan I; Lemaur, Vincent; Polo, Federico; Fröhlich, Roland; Cornil, Jêrôme; De Cola, Luisa


    Synthetic control of the mutual arrangement of the cyclometalated ligands (C^N) in Ir(III) dimers, [Ir(C^N)(2)Cl](2), and cationic bis-cyclometalated Ir(III) complexes, [Ir(C^N)(2)(L^L)](+) (L^L = neutral ligand), is described for the first time. Using 1-benzyl-4-(2,4-difluorophenyl)-1H-1,2,3-triazole (HdfptrBz) as a cyclometalating ligand, two different Ir(III) dimers, [Ir(dfptrBz)(2)Cl](2), are synthesized depending on the reaction conditions. At 80 °C, the dimer with an unusual mutual cis-C,C and cis-N,N configuration of the C^N ligands is isolated. In contrast, at higher temperature (140 °C), the geometrical isomer with the common cis-C,C and trans-N,N arrangement of the C^N ligand is obtained. In both cases, an asymmetric bridge, formed by a chloro ligand and two adjacent nitrogens of the triazole ring of one of the cyclometalated ligands, is observed. The dimers are cleaved in coordinating solvents to give the solvento complexes [Ir(dfptrBz)(2)Cl(S)] (S = DMSO or acetonitrile), which maintain the C^N arrangement of the parent dimers. Controlling the C^N ligand arrangement in the dimers allows for the preparation of the first example of geometrical isomers of a cationic bis-cyclometalated Ir(III) complex. Thus, N,N-trans-[Ir(dfptrBz)(2)(dmbpy)](+) (dmbpy = 4,4'-dimethyl-2,2'-bipyridine), with cis-C,C and trans-N,N arrangement of the C^N ligands, as well as N,N-cis-[Ir(dfptrBz)(2)(dmbpy)](+), with cis-C,C and cis-N,N C^N ligand orientation, are synthesized and characterized. Interestingly, both isomers show significantly different photophysical and electroluminescent properties, depending on the mutual arrangement of the C^N ligands. Furthermore, quantum chemical calculations give insight into the observed photophysical experimental data.

  17. Differentiation of flavonoid glycoside isomers by using metal complexation and electrospray ionization mass spectrometry. (United States)

    Pikulski, Michael; Brodbelt, Jennifer S


    The elucidation of flavonoid isomers is accomplished by electrospray ionization tandem mass spectrometry (ESI-MS/MS) via formation and collisional activated dissociation (CAD) of metal/flavonoid complexes containing an auxiliary ligand. Addition of a metal salt and a suitable neutral auxiliary ligand to flavonoids in solution results in the formation of [M(II) (flavonoid-H) ligand]+ complexes by ESI which, upon collisional activated dissociation, often result in more distinctive fragmentation patterns than observed for conventional protonated or deprotonated flavonoids. Previously, 2,2'-bipyridine was used as an auxiliary ligand, and now we compare and explore the use of alternative pyridyl ligands, including 4,7-diphenyl-1,10-phenanthroline. Using this technique, three groups of flavonoid glycoside isomers are differentiated, including glycosides of apigenin, quercetin, and luteolin.

  18. Exclusive accumulation of Z-isomers of monolignols and their glucosides in bark of Fagus grandifolia (United States)

    Lewis, N. G.; Inciong, E. J.; Ohashi, H.; Towers, G. H.; Yamamoto, E.


    In addition to Z-coniferyl and Z-sinapyl alcohols, bark extracts of Fagus grandifolia also contain significant amounts of the glucosides, Z-coniferin, Z-isoconiferin (previously called faguside) and Z-syringin. The corresponding E-isomers of these glucosides do not accumulate to a detectable level. The accumulation of the Z-isomers suggests that either they are not lignin precursors or that they are reservoirs of monolignols for subsequent lignin biosynthesis; it is not possible to distinguish between these alternatives. The co-occurrence of Z-coniferin and Z-isoconiferin demonstrate that glucosylation of monolignols can occur at either the phenolic or the allylic hydroxyl groups.

  19. Decays of the {sup 97}Y isomers to the single neutron nucleus {sup 97}Zr

    Energy Technology Data Exchange (ETDEWEB)

    Lhersonneau, G.; Dendooven, P.; Hankonen, S.; Honkanen, A.; Huhta, M.; Julin, R.; Juutinen, S.; Oinonen, M.; Penttilae, H.; Savelius, A.; Toermaenen, S.; Aeystoe, J. [Department of Physics, University of Jyvaeskylae, Finland, P.O. Box 35, FIN-40351 Jyvaeskylae (Finland); Butler, P.A.; Cocks, J.F.; Jones, P.M.; Smith, J.F. [Oliver Lodge Laboratory, University of Liverpool, P.O. Box 147, Liverpool L69 3BX (United Kingdom)


    The decays of the 9/2{sup +} and of the three-quasiparticle high spin isomer in {sup 97}Y have been investigated following on-line mass separation with the ion-guide technique. Spins and parities for several of the lowest-lying levels in the daughter nucleus {sup 97}Zr are revised and configurations are proposed. In particular, the 2264 keV level is identified as the {ital h}{sub 11/2} single-neutron level. The population of a cascade on top of the {ital h}{sub 11/2} level provides evidence for Gamow-Teller {beta} decay of the high-spin {sup 97}Y isomer. Levels and transition rates are qualitatively well reproduced by regarding {sup 97}Zr as a single-neutron nucleus with respect to the doubly closed {sup 96}Zr core. {copyright} {ital 1996 The American Physical Society.}

  20. Adsorptive process design for the separation of hexane isomers using zeolites. (United States)

    Luna-Triguero, A; Gómez-Álvarez, P; Calero, S


    The product of catalytic isomerization is a mixture of linear and branched hydrocarbons that are in thermodynamic equilibrium, and their separation becomes necessary in the petrochemical industry. Zeolite 5A is usually industrially used to sieve alkane isomers, but its pore size allows only the separation of linear alkanes from the monobranched and dibranched alkanes by a kinetic mechanism. A more efficient approach to improve the average research octane number would be to adsorptively separate the di-methyl alkanes as products and recycle both the linear and mono-methyl alkanes to the isomerization reactor. Since the microscopic processes of adsorbates in zeolites are generally difficult or impossible to determine by experiments, especially in the case of mixtures, molecular simulation represents an attractive alternative. In this computational study, we propose a conceptual separation process for hexane isomers consisting of several adsorptive steps. Different zeolite topologies were examined for their ability to conduct this separation based on adsorption equilibrium and kinetics.

  1. Large-scale shell model study of the newly found isomer in 136La (United States)

    Teruya, E.; Yoshinaga, N.; Higashiyama, K.; Nishibata, H.; Odahara, A.; Shimoda, T.


    The doubly-odd nucleus 136La is theoretically studied in terms of a large-scale shell model. The energy spectrum and transition rates are calculated and compared with the most updated experimental data. The isomerism is investigated for the first 14+ state, which was found to be an isomer in the previous study [Phys. Rev. C 91, 054305 (2015), 10.1103/PhysRevC.91.054305]. It is found that the 14+ state becomes an isomer due to a band crossing of two bands with completely different configurations. The yrast band with the (ν h11/2 -1⊗π h11 /2 ) configuration is investigated, revealing a staggering nature in M 1 transition rates.

  2. An experimental and kinetic modelling study of the oxidation of the four isomers of butanol

    CERN Document Server

    Moss, J T; Oehlschlaeger, M A; Biet, Joffrey; Warth, Valérie; Glaude, Pierre-Alexandre; Battin-Leclerc, Frédérique; 10.1021/jp806464p


    Butanol, an alcohol which can be produced from biomass sources, has received recent interest as an alternative to gasoline for use in spark ignition engines and as a possible blending compound with fossil diesel or biodiesel. Therefore, the autoignition of the four isomers of butanol (1-butanol, 2-butanol, iso-butanol, and tert-butanol) has been experimentally studied at high temperatures in a shock tube and a kinetic mechanism for description of their high-temperature oxidation has been developed. Ignition delay times for butanol/oxygen/argon mixtures have been measured behind reflected shock waves at temperatures and pressures ranging from approximately 1200 to 1800 K and 1 to 4 bar. Electronically excited OH emission and pressure measurements were used to determine ignition delay times. A detailed kinetic mechanism has been developed to describe the oxidation of the butanol isomers and validated by comparison to the shock tube measurements. Reaction flux and sensitivity analysis indicate that the consumpti...

  3. Spectroscopic quadrupole moments of high-spin isomers in {sup 193}Pb

    Energy Technology Data Exchange (ETDEWEB)

    Balabanski, D.L. [IKS, University of Leuven, Celestijnenlaan 200 D, B-3001, Leuven (Belgium); Faculty of Physics, St. Kliment Ohridski University of Sofia, BG-1164, Sofia (Bulgaria); Ionescu-Bujor, M.; Iordachescu, A.; Bucurescu, D. [National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest (Romania); Bazzacco, D.; Brandolini, F.; Menegazzo, R.; Pavan, P.; Rossi Alvarez, C. [Dipartimento di Fisica dell' Universita di Padova and INFN, Sezione di Padova, Padova (Italy); Chmel, S.; Huebel, H. [ISKP, Universitaet Bonn, D-53115, Bonn (Germany); Danchev, M. [Faculty of Physics, St. Kliment Ohridski University of Sofia, BG-1164, Sofia (Bulgaria); De Poli, M. [Laboratori Nazionali di Legnaro, INFN, Legnaro (Italy); Georgiev, G. [Grand Accelerateur National d' Ions Lourds, F-14076, Caen Cedex 5 (France); Haas, H. [Bereich Festkorperphysik, Hahn-Meitner Institut, D-14109, Berlin (Germany); Marginean, N. [National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest (Romania); Laboratori Nazionali di Legnaro, INFN, Legnaro (Italy); Neyens, G.; Vyvey, K. [IKS, University of Leuven, Celestijnenlaan 200 D, B-3001, Leuven (Belgium); Rainovski, G. [Faculty of Physics, St. Kliment Ohridski University of Sofia, BG-1164, Sofia (Bulgaria); Department of Physics, University of Liverpool, L69 7ZE, Liverpool (United Kingdom); Ur, C.A. [National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest (Romania); Dipartimento di Fisica dell' Universita di Padova and INFN, Sezione di Padova, Padova (Italy); Frauendorf, S.


    The quadrupole interaction of high-spin isomers in {sup 193}Pb implanted into solid Hg cooled at a temperature T=170 K has been investigated by the time-differential perturbed {gamma}-ray angular-distribution method. Spectroscopic quadrupole moment values of vertical stroke Q{sub s} vertical stroke =0.22(2) eb and 0.45(4) eb have been deduced for the 21/2{sup -} and 33/2{sup +} three-neutron states, respectively. A much higher value vertical stroke Q{sub s} vertical stroke =2.84(26) eb has been determined for the 29/2{sup -} isomer, the band head of a magnetic rotational band. (orig.)

  4. Supramolecular isomers, water clusters and solvent-mediated transformations in a series of lanthanide MOFs (United States)

    Michaelides, Adonis; Skoulika, Stavroula


    A series of Lanthanide MOFs of hydromuconic acid (H2hymuc) with cations of different size (La3+, Ce3+, Gd3+, Y3+) were generated at room temperature, pH = 5.5-5.8, using water as solvent. Two microporous genuine supramolecular isomers were found for the larger cations (La3+, Ce3+) sustained either by discrete (H2O)18 clusters or by infinite water tapes, consisting of fused tetramers, pentamers and hexamers. The smaller cations (Gd3+, Y3+) produced a 2D phase, considered as catenane isomer of previously published lanthanide MOFs with adipic acid. MOFs obtained with Ce3+, Gd3+and Y3+ undergo irreversible solvent-mediated transformation, yielding isomorphous 3D two-fold interpenetrated MOFs. The close structural similarity between the 2D phase and the 3D interpenetrated one indicated a possible mechanism for this transformation.

  5. Mass measurements and implications for the energy of the high-spin isomer in 94Ag

    CERN Document Server

    Kankainen, A; Batist, L; Eliseev, S; Eronen, T; Hager, U; Hakala, J; Jokinen, A; Moore, I D; Novikov, Yu N; Pentillä, H; Popov, A; Rahaman, S; Rinta-Antila, S; Rissanen, J; Saastamoinen, A; Seliverstov, D M; Sonoda, T; Vorobjev, G; Weber, C; Äystö, J


    Nuclides in the vicinity of 94Ag have been studied with the Penning trap mass spectrometer JYFLTRAP at IGISOL. The masses of the two-proton decay daughter 92Rh and the beta-decay daughter 94Pd of the high-spin isomer in 94Ag have been measured and the masses of 93Pd and 94Ag have been deduced. When combined with the data from the one-proton or two-proton decay experiments, the results lead to contradictory mass excess values for the high-spin isomer in 94Ag, -46370(170) keV or -44970(100) keV, corresponding to excitation energies of 6960(400) keV or 8360(370) keV, respectively.

  6. Electronic single-molecule identification of carbohydrate isomers by recognition tunnelling (United States)

    Im, Jongone; Biswas, Sovan; Liu, Hao; Zhao, Yanan; Sen, Suman; Biswas, Sudipta; Ashcroft, Brian; Borges, Chad; Wang, Xu; Lindsay, Stuart; Zhang, Peiming


    Carbohydrates are one of the four main building blocks of life, and are categorized as monosaccharides (sugars), oligosaccharides and polysaccharides. Each sugar can exist in two alternative anomers (in which a hydroxy group at C-1 takes different orientations) and each pair of sugars can form different epimers (isomers around the stereocentres connecting the sugars). This leads to a vast combinatorial complexity, intractable to mass spectrometry and requiring large amounts of sample for NMR characterization. Combining measurements of collision cross section with mass spectrometry (IM-MS) helps, but many isomers are still difficult to separate. Here, we show that recognition tunnelling (RT) can classify many anomers and epimers via the current fluctuations they produce when captured in a tunnel junction functionalized with recognition molecules. Most importantly, RT is a nanoscale technique utilizing sub-picomole quantities of analyte. If integrated into a nanopore, RT would provide a unique approach to sequencing linear polysaccharides.

  7. Characterization of tetra-aryl benzene isomers by using preparative gas chromatography with mass spectrometry, nuclear magnetic resonance spectroscopy, and X-ray crystallographic methods. (United States)

    Rühle, Christian P G; Niere, Julie; Morrison, Paul D; Jones, Roderick C; Caradoc-Davies, Tom; Canty, Allan J; Gardiner, Michael G; Tolhurst, Vicki-Anne; Marriott, Philip J


    The present study describes a preparative gas chromatographic (GC) approach employed to study a series of products arising from reaction of phenylacetylene with para-substituted aryl-iodides under Sonogashira catalysis conditions. GC analysis resolves the isomers from each reaction; however, it cannot provide structural details (their MS data are virtually identical). Since classical liquid chromatography cannot resolve the isomers, preparative-scale GC is the only practical approach to provide further spectroscopic characterization of the isomers. The products are well separated by GC so a single thick-film capillary column is adequate for this case, with operation up to approximately +300 degrees C. By collection of 50+ repeat injections, sufficient material could be isolated for (1)H NMR spectral analysis of the isomers, and for one isomer (isomer I) of a number of analogous related catalytic reaction mixtures, X-ray crystal structure determination enabled complete structural elucidation (absolute configuration) of the substitution pattern of the structure of this isomer. This confirmed isomer I to be the 2-para-aryl-substituted 1,3,5-triphenylbenzene product in all cases. (1)H NMR spectra of isomer I products generally had similar patterns but differed markedly from the second major isomer product (isomer II).

  8. Determination of ortho-cresyl phosphate isomers of tricresyl phosphate used in aircraft turbine engine oils by gas chromatography and mass spectrometry. (United States)

    De Nola, G; Kibby, J; Mazurek, W


    Tricresyl phosphate (TCP) is used as an anti-wear additive in aircraft turbine engine oil. Concerns about its toxicity are largely based on the tri-o-cresyl phosphate isomer content. However, the presence of other and more toxic isomers has been previously suggested. In this work, the structural isomers of TCP have been determined by two methods (experimental and semi-theoretical). First, the TCP isomers were separated by gas chromatography (GC) and identified by mass spectrometry (MS). Second, after base cleavage of TCP, GC was used to quantify the cresol precursors. These results were used to calculate the TCP isomer distribution based on the assumption of a statistical distribution of the TCP isomers. The results from the two determinations showed reasonable agreement for three of the four oils studied. The o-cresyl isomers were found to be present almost exclusively as the more toxic mono-o-cresyl isomers in the concentration range 13-150 mg/L. The ability to analyse for the mono-o-cresyl isomers allows the toxicity of TCP to be based on the latter isomers rather than on the less toxic tri-o-cresyl phosphate isomer.

  9. g Factor of the 7{sup -} isomer in {sup 126}Sn and first observation of spin-alignment in relativistic fission

    Energy Technology Data Exchange (ETDEWEB)

    Ilie, G., E-mail: gabriela.ilie@yale.ed [IKP, Universitaet zu Koeln, 50937 Koeln (Germany); National Institute for Physics and Nuclear Engineering, 76900 Bucharest (Romania); Neyens, G. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, 3001 Leuven (Belgium); Simpson, G.S. [ILL, 38042 Grenoble Cedex (France); LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, INPG, 38026 Grenoble Cedex (France); Jolie, J.; Blazhev, A. [IKP, Universitaet zu Koeln, 50937 Koeln (Germany); Grawe, H. [GSI, 64291 Darmstadt (Germany); Lozeva, R.L. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, 3001 Leuven (Belgium); Faculty of Physics, University of Sofia ' St. Kl. Ohridski' , 1164 Sofia (Bulgaria); Vermeulen, N. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, 3001 Leuven (Belgium); Atanasova, L. [Faculty of Physics, University of Sofia ' St. Kl. Ohridski' , 1164 Sofia (Bulgaria); Balabanski, D.L. [Dipartimento di Fisica, Universita di Camerino, 62032 Camerino (Italy); INRNE, Bulgarian Academy of Sciences, 1784 Sofia (Bulgaria); Becker, F. [GSI, 64291 Darmstadt (Germany); Bednarczyk, P. [GSI, 64291 Darmstadt (Germany); The Henryk Niewodniczanski Institute of Nuclear Physics, PAN, 31342 Krakow (Poland); Brandau, C. [GSI, 64291 Darmstadt (Germany); Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Caceres, L. [GSI, 64291 Darmstadt (Germany); Departamento de Fisica Teorica, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Chamoli, S.K. [Department of Particle Physics, Weizmann Institute of Science, 76100 Rehovot (Israel); Daugas, J.M. [CEA, DAM, DIF, 91297 Arpajon Cedex (France); Doornenbal, P.; Gerl, J.; Gorska, M. [GSI, 64291 Darmstadt (Germany); Grebosz, J. [GSI, 64291 Darmstadt (Germany); The Henryk Niewodniczanski Institute of Nuclear Physics, PAN, 31342 Krakow (Poland)


    We report on the g factor measurement of the isomeric 7{sup -} state (E{sup *}=2219 keV, T{sub 1/2}=5.9(8) mus) in the neutron-rich {sup 126}Sn nucleus. The nucleus was produced by the fission of a relativistic {sup 238}U beam and reaction products were selected by the FRS fragment separator at GSI. For the first time, spin-alignment was observed after relativistic fission. It was used to deduce the g factor of the 7{sup -} isomeric state, g(7{sup -})=-0.098(9), from the measured perturbed angular distribution of its gamma decay using the RISING Cluster detectors. The observed value confirms the suggested nu(h{sub 11/2}{sup -1}d{sub 3/2}{sup -1}) dominant configuration, which has been proposed for the 7{sup -} isomers in neutron-rich Sn isotopes. The failure of the g factor additivity rule and the importance of core polarization evolution with increasing distance from the doubly-magic {sup 132}Sn is discussed. The first observation of 18(8)% of spin-alignment produced by the relativistic fission of a {sup 238}U beam paves the way to study moments of neutron-rich (sub-)microsecond isomers, which are difficult to align by other means.

  10. The influence hydrogen atom addition has on charge switching during motion of the metal atom in endohedral Ca@C60H4 isomers. (United States)

    Raggi, G; Besley, E; Stace, A J


    Density functional theory has been applied in a study of charge transfer between an endohedral calcium atom and the fullerene cage in Ca@C60H4 and [Ca@C60H4](+) isomers. Previous calculations on Ca@C60 have shown that the motion of calcium within a fullerene is accompanied by large changes in electron density on the carbon cage. Based on this observation, it has been proposed that a tethered endohedral fullerene might form the bases of a nanoswitch. Through the addition of hydrogen atoms to one hemisphere of the cage it is shown that, when compared with Ca@C60, asymmetric and significantly reduced energy barriers can be generated with respect to motion of the calcium atom. It is proposed that hydrogen atom addition to a fullerene might offer a route for creating a bi-stable nanoswitch that can be fine-tuned through the selection of an appropriate isomer and number of atoms attached to the cage of an endohedral fullerene.This article is part of the themed issue 'Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene'.

  11. Isomer-specific regulation of metabolism and PPARgamma signaling by CLA in human preadipocytes

    DEFF Research Database (Denmark)

    Brown, J Mark; Boysen, Maria Sandberg; Jensen, Søren Skov


    in primary human adipocytes in vitro. Here we investigated the mechanism behind the isomer-specific, CLA-mediated reduction in TG accumulation in differentiating human preadipocytes. Trans-10,cis-12 CLA decreased insulin-stimulated glucose uptake and oxidation, and reduced insulin-dependent glucose...... uptake and oxidation and preadipocyte differentiation by altering preadipocyte gene transcription in a manner that appeared to be due, in part, to decreased PPARgamma expression....

  12. Ignition of Isomers of Pentane: An Experimental and Kinetic Modeling Study (United States)


    diesel engines [26,27], and ignition under homogeneous charge compres- sion ignition ( HCCI ) conditions [26,28]. Kinetic modeling shows that the isomers of...Introduction Hydrocarbon ignition is important in many prac- tical combustion systems, including internal com- bustion engines , detonations, pulse combustors...tem- peratures are similar to those in automotive engines during diesel ignition and end-gas autoignition in spark-ignition engines . The RCM provides

  13. Catalytic Oxidative Dehydration of Butanol Isomers: 1-Butanol, 2-Butanol, and Isobutanol (United States)


    G.; Russo, M. E.; Marzocchella, A.; Salatino, P. Butanol Production by Clostridium Acetobutylicum in a Continuous Packed Bed Reactor. Journal because it is easily available through fermentation of non-food biomass and wastewater (1–3). Dehydration of butanol isomers (1-butanol, 2... Fermentative Butanol Production by Clostridia. Biotechnology and Bioengineering 2008, 101, 209–228. 3. Zverlov, V. V.; Berezina, O.; Velikodvorskaya, G. A

  14. Analysis of shape isomer yields of 237Pu in the framework of dynamical–statistical model

    Indian Academy of Sciences (India)

    Hadi Eslamizadeh


    Data on shape isomer yield for + 235U reaction at $E^{\\text{lab}}$ = 20–29 MeV are analysed in the framework of a combined dynamical–statistical model. From this analysis, information on the double humped fission barrier parameters for some Pu isotopes has been obtained and it is shown that the depth of the second potential well should be less than the results of statistical model calculations.

  15. Efficient algorithms to enumerate isomers and diamutamers with more than one type of substituent (United States)

    van Almsick M; Dolhaine; Honig


    In this paper we describe numeric as well as symbolic algorithms for the enumeration of substitutional isomers with an unlimited number of different achiral substituents. We consider three different scenarios: first, the enumeration of diamutamers with a given set of ligand types and ligand multiplicity, second, the enumeration of diamutamer libraries with a given ligand assortment pattern, and, third, the enumerations of libraries with diamutamers exhibiting a limited number of ligands.

  16. Separation and identification of Taxifolin 3-O-glucoside isomers from Chamaecyparis obtusa (Cupressaceae). (United States)

    Sakushima, Akiyo; Ohno, Kosei; Coskun, Makusut; Seki, Koh-Ichi; Ohkura, Kazue


    Taxifolin 3-O-glucoside isomers, [(2R, 3R)-, (2R, 3S)-, (2S, 3R)- and (2S, 3S)-] were isolated from leaves of Chamaecyparis obtuse (Cupressaceae). Their structures were elucidated on the basis of UV, MS, CD, 1H- and 13C-NMR spectral data, including 2D shift correlation. It was found that the compounds could be distinguished by the use of 1H- and 13C-NMR spectral data.

  17. Investigation of HNCO isomer formation in ice mantles by UV and thermal processing: An experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez-Escobar, A.; Giuliano, B. M.; Caro, G. M. Muñoz; Cernicharo, J. [Centro de Astrobiología, INTA-CSIC, Carretera de Ajalvir, km 4, Torrejón de Ardoz, E-28850 Madrid (Spain); Marcelino, N., E-mail: [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)


    Current gas-phase models do not account for the abundances of HNCO isomers detected in various environments, suggesting their formation in icy grain mantles. We attempted to study a formation channel of HNCO and its possible isomers by vacuum-UV photoprocessing of interstellar ice analogs containing H{sub 2}O, NH{sub 3}, CO, HCN, CH{sub 3}OH, CH{sub 4}, and N{sub 2} followed by warm-up under astrophysically relevant conditions. Only the H{sub 2}O:NH{sub 3}:CO and H{sub 2}O:HCN ice mixtures led to the production of HNCO species. The possible isomerization of HNCO to its higher energy tautomers following irradiation or due to ice warm-up has been scrutinized. The photochemistry and thermal chemistry of H{sub 2}O:NH{sub 3}:CO and H{sub 2}O:HCN ices were simulated using the Interstellar Astrochemistry Chamber, a state-of-the-art ultra-high-vacuum setup. The ice was monitored in situ by Fourier transform mid-infrared spectroscopy in transmittance. A quadrupole mass spectrometer detected the desorption of the molecules in the gas phase. UV photoprocessing of H{sub 2}O:NH{sub 3}:CO and H{sub 2}O:HCN ices lead to the formation of OCN{sup –} as a main product in the solid state and a minor amount of HNCO. The second isomer HOCN has been tentatively identified. Despite its low efficiency, the formation of HNCO and the HOCN isomers by UV photoprocessing of realistic simulated ice mantles might explain the observed abundances of these species in photodissociation regions, hot cores, and dark clouds.


    Energy Technology Data Exchange (ETDEWEB)

    Staszczak, A. [Maria Curie-Sklodowska University, Poland; Wong, Cheuk-Yin [ORNL


    Nuclei under non-collective rotation with a large angular momentum above some threshold can assume a toroidal shape. In our previous work, we showed by using cranked Skyrme Hartree Fock approach that even even, N = Z, high-K, toroidal isomeric states may have general occurrences for light nuclei with 28 < A < 52. We present here some additional results and systematics on the particle-hole nature of these high-spin toroidal isomers.

  19. Detection of biologically active isomers of conjugated linoleic acid in kaymak


    Ökten, Sevtap; Gönç, Siddik; Tokusoglu, Özlem; Sibel Akalin, A.


    Numerous physiological effects are attributed to conjugated linoleic acids (CLA). Biologically active isomers of CLA ( cis -9, trans -11 (C18:2) and trans- 10, cis- 12 (C18:2)) have been reported to have anticarcinogenic, antioxidative and antiatherosclerotic properties. Relatively rich sources of CLA include milk fat-containing foods such as kaymak. Kaymak is a kind of concentrated cream which is traditionally manufactured from buffalo or cow's milk mainly in Turkey . The objective of this s...

  20. Trans fatty acid isomers from hydrogenated fats: The controversy about health implications


    Valenzuela, Alfonso; King, Judith; Nieto, Susana


    Wherever there is a double bond in a fatty acid, there is also a possibility for isomerization. Under partial hydrogenation triacylglycerols composing oils'double bonds may change from cis to trans configuration, therefore products derived from hydrogenated oils such as margarines, shortenings and other industrial fats show high content of trans fatty acid isomers. The health implications of trans fatty acids in our d...

  1. Low and High Temperature Combustion Chemistry of Butanol Isomers in Premixed Flames and Autoignition Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sarathy, S M; Pitz, W J; Westbrook, C K; Mehl, M; Yasunaga, K; Curran, H J; Tsujimura, T; Osswald, P; Kohse-Hoinghaus, K


    Butanol is a fuel that has been proposed as a bio-derived alternative to conventional petroleum derived fuels. The structural isomer in traditional 'bio-butanol' fuel is n-butanol, but newer conversion technologies produce iso-butanol as a fuel. In order to better understand the combustion chemistry of bio-butanol, this study presents a comprehensive chemical kinetic model for all the four isomers of butanol (e.g., 1-, 2-, iso- and tert-butanol). The proposed model includes detailed high temperature and low temperature reaction pathways. In this study, the primary experimental validation target for the model is premixed flat low-pressure flame species profiles obtained using molecular beam mass spectrometry (MBMS). The model is also validated against previously published data for premixed flame velocity and n-butanol rapid compression machine and shock tube ignition delay. The agreement with these data sets is reasonably good. The dominant reaction pathways at the various pressures and temperatures studied are elucidated. At low temperature conditions, we found that the reaction of alphahydroxybutyl with O{sub 2} was important in controlling the reactivity of the system, and for correctly predicting C{sub 4} aldehyde profiles in low pressure premixed flames. Enol-keto isomerization reactions assisted by HO{sub 2} were also found to be important in converting enols to aldehydes and ketones in the low pressure premixed flames. In the paper, we describe how the structural features of the four different butanol isomers lead to differences in the combustion properties of each isomer.

  2. Interactions between major chlorogenic acid isomers and chemical changes in coffee brew that affect antioxidant activities. (United States)

    Liang, Ningjian; Xue, Wei; Kennepohl, Pierre; Kitts, David D


    Coffee bean source and roasting conditions significantly (pcoffee. CGA isomer content was positively correlated (pcoffee to reduce nitric oxide and scavenge Frémy's salt. Indices of browning in roasted coffee were positively correlated (pcoffee corresponded to intracellular antioxidant capacity measured in Caco-2 intestinal cells. This study concluded that the intracellular antioxidant capacity that best describes potential health benefits of coffee positively corresponds best with CGA content.

  3. Coordinate mapping of hyolaryngeal mechanics in swallowing. (United States)

    Thompson, Thomas Z; Obeidin, Farres; Davidoff, Alisa A; Hightower, Cody L; Johnson, Christohper Z; Rice, Sonya L; Sokolove, Rebecca-Lyn; Taylor, Brandon K; Tuck, John M; Pearson, William G


    Characterizing hyolaryngeal movement is important to dysphagia research. Prior methods require multiple measurements to obtain one kinematic measurement whereas coordinate mapping of hyolaryngeal mechanics using Modified Barium Swallow (MBS) uses one set of coordinates to calculate multiple variables of interest. For demonstration purposes, ten kinematic measurements were generated from one set of coordinates to determine differences in swallowing two different bolus types. Calculations of hyoid excursion against the vertebrae and mandible are correlated to determine the importance of axes of reference. To demonstrate coordinate mapping methodology, 40 MBS studies were randomly selected from a dataset of healthy normal subjects with no known swallowing impairment. A 5 ml thin-liquid bolus and a 5 ml pudding swallows were measured from each subject. Nine coordinates, mapping the cranial base, mandible, vertebrae and elements of the hyolaryngeal complex, were recorded at the frames of minimum and maximum hyolaryngeal excursion. Coordinates were mathematically converted into ten variables of hyolaryngeal mechanics. Inter-rater reliability was evaluated by Intraclass correlation coefficients (ICC). Two-tailed t-tests were used to evaluate differences in kinematics by bolus viscosity. Hyoid excursion measurements against different axes of reference were correlated. Inter-rater reliability among six raters for the 18 coordinates ranged from ICC = 0.90 - 0.97. A slate of ten kinematic measurements was compared by subject between the six raters. One outlier was rejected, and the mean of the remaining reliability scores was ICC = 0.91, 0.84 - 0.96, 95% CI. Two-tailed t-tests with Bonferroni corrections comparing ten kinematic variables (5 ml thin-liquid vs. 5 ml pudding swallows) showed statistically significant differences in hyoid excursion, superior laryngeal movement, and pharyngeal shortening (p Pearson correlations of hyoid excursion measurements from two different

  4. The coordination chemistry of boron porphyrin complexes B2OX2 (TYPP) (X = OH, F; Y = Cl, CH3) and their chemical reactivities

    Indian Academy of Sciences (India)

    G I Cárdenas-Jirón; F Espinoza-Leyton; T L Sordo


    The structure and coordination chemistry of boron porphyrin complexes B2OX2 (TYPP) (X = OH, F; Y = Cl, CH3) in connection with its chemical reactivity are analyzed at ab initio density functional theory B3LYP/6-31G∗ and restricted Hartree-Fock RHF/6-31G∗ levels of theory. Global reactivity and local selectivity descriptors are used as adequate tools to analyze the isomerism effect ( or isomer) and the substitution effect (X: in axial ligand; or Y: in porphyrin ligand). In all the cases, we find that the conformation is the most stable one, in agreement with X-ray results, and that a principle of maximum hardness in the isomerism analysis is fullfilled. In the substitution analysis, we find that the three global reactivity indexes (, , ) and the two local reactivity indexes (, electrostatic potential) used in this paper predict the same trend when an electron-withdrawing substituent is replaced by an electron donor. Finally, we show that substitution in the porphyrin ligand is slightly more significant than that in the axial ligand.

  5. The Immunomodulatory Activity of Jacaric Acid, a Conjugated Linolenic Acid Isomer, on Murine Peritoneal Macrophages.

    Directory of Open Access Journals (Sweden)

    Wai Nam Liu

    Full Text Available This study aims at demonstrating the immunomodulatory property of jacaric acid, a conjugated linolenic acid (CLNA isomer that is present in jacaranda seed oil, on murine peritoneal macrophages. Our results showed that jacaric acid exhibited no significant cytotoxicity on the thioglycollate-elicited murine peritoneal macrophages as revealed by the neutral red uptake assay, but markedly increased their cytostatic activity on the T-cell lymphoma MBL-2 cells as measured by the fluorometric CyQuant® NF Cell Proliferation Assay Kit. Flow cytometric analysis indicated that jacaric acid could enhance the endocytic activity of macrophages and elevated their intracellular production of superoxide anion. Moreover, jacaric acid-treated macrophages showed an increase in the production of nitric oxide which was accompanied by an increase in the expression level of inducible nitric oxide synthase protein. In addition, the secretion of several pro-inflammatory cytokines, including interferon-γ, interleukin-1β and tumor necrosis factor-α, was up-regulated. Collectively, our results indicated that the naturally-occurring CLNA isomer, jacaric acid, could exhibit immunomodulating activity on the murine peritoneal macrophages in vitro, suggesting that this CLNA isomer may act as an immunopotentiator which can be exploited for the treatment of some immunological disorders with minimal toxicity and fewer side effects.

  6. Prospect of triggering the 178m2Hf isomer and the role of resonance conversion (United States)

    Karpeshin, F. F.; Trzhaskovskaya, M. B.; Zhang, J.


    A mechanism of triggering the 12.7keV E3 transition, based on the new decay mode of the 31y isomer via resonance internal conversion and emission of a 1.4keV X-ray quantum, is considered. Actually, this decay mode was observed previously in the decay of 45- and 46-fold ions of 125Te . For the purpose of triggering, the atomic radiative vertex has to be induced by resonance radiation. This mechanism makes triggering by an order of magnitude more efficient than triggering a bare nucleus, and is achieved at a lower combination frequency. An experiment is proposed for the direct observation of the new decay mode. This also offers a new way of resonance scattering of these X-rays. Triggering through higher-lying 2573 and 2805keV states is also considered. The results are extended to the general problem of triggering. The main obstacle for enhancing the efficiency is a high internal conversion rate. For this reason, shape isomers with low multipole order -- E1 , M1 , and with a high enough energy of triggering transition are of interest for triggering. The partial ionization of the outer electrons will also help. The same recommendations hold for triggering isomers in laser-produced plasma.

  7. Control of multiscale systems with constraints. 2. Fractal nuclear isomers and clusters

    CERN Document Server

    Adamenko, S; Novikov, V


    We consider the influence of the Fermi statistics of nucleons on the binding energy of a new type of nuclear structures such as fractal nuclear clusters (fractal isomers of nuclei). It is shown that the fractal nuclear isomers possess a wide spectrum of binding energies that exceed, in many cases, the values known at the present time. The transition of the nuclear matter in the form of ordinary nuclei (drops of the nuclear fluid) in the state with the fractal structure or in the form of bubble nuclei opens new sources of energy and has huge perspectives. This transition is based on a new state of matter - collective coherently correlated state. It manifests itself, first of all, in the property of nonlocality of nuclear multiparticle processes. We develop a phenomenological theory of the binding energy of nuclear fractal structures and modify the Bethe - Weizs\\"acker formula for nuclear clusters with the mass number A, charge Z, and fractal dimension D_f. The consideration of fractal nuclear isomers allows on...

  8. Partition function and astronomical observation of interstellar isomers: Is there a link? (United States)

    Etim, Emmanuel E.; Arunan, Elangannan


    The unsuccessful astronomical searches for some important astrophysical and astrobiological molecules have been linked to the large partition function of these molecules. This letter reports an extensive investigation of the relationship between partition function and astronomical observation of interstellar isomers using high level quantum chemical calculations. 120 molecules from 30 different isomeric groups have been considered. Partition function and thermodynamic stabilities are determined for each set of isomeric species. From the results, there is no direct correlation between partition function and astronomical observation of the same isomeric species. Though interstellar formations processes are generally controlled by factors like kinetics, thermodynamics, formation and destruction pathways. However, the observation of the isomers seems to correlate well with thermodynamics. For instance, in all the groups considered, the astronomically detected isomers are the thermodynamically most stable molecules in their respective isomeric groups. The implications of these results in accounting for the limited number of known cyclic interstellar molecules, unsuccessful searches for amino acid and the possible molecules for astronomical observations are discussed.

  9. Profiling of the Molecular Weight and Structural Isomer Abundance of Macroalgae-Derived Phlorotannins

    Directory of Open Access Journals (Sweden)

    Natalie Heffernan


    Full Text Available Phlorotannins are a group of complex polymers of phloroglucinol (1,3,5-trihydroxybenzene unique to macroalgae. These phenolic compounds are integral structural components of the cell wall in brown algae, but also play many secondary ecological roles such as protection from UV radiation and defense against grazing. This study employed Ultra Performance Liquid Chromatography (UPLC with tandem mass spectrometry to investigate isomeric complexity and observed differences in phlorotannins derived from macroalgae harvested off the Irish coast (Fucus serratus, Fucus vesiculosus, Himanthalia elongata and Cystoseira nodicaulis. Antioxidant activity and total phenolic content assays were used as an index for producing phlorotannin fractions, enriched using molecular weight cut-off dialysis with subsequent flash chromatography to profile phlorotannin isomers in these macroalgae. These fractions were profiled using UPLC-MS with multiple reaction monitoring (MRM and the level of isomerization for specific molecular weight phlorotannins between 3 and 16 monomers were determined. The majority of the low molecular weight (LMW phlorotannins were found to have a molecular weight range equivalent to 4–12 monomers of phloroglucinol. The level of isomerization within the individual macroalgal species differed, resulting in substantially different numbers of phlorotannin isomers for particular molecular weights. F. vesiculosus had the highest number of isomers of 61 at one specific molecular mass, corresponding to 12 phloroglucinol units (PGUs. These results highlight the complex nature of these extracts and emphasize the challenges involved in structural elucidation of these compounds.

  10. Screening of multicomponent crystals of L-tryptophan with three isomers of pyridinedicarboxylic acids (United States)

    Das, Babulal


    Multicomponent crystallization of L-tryptophan with three different isomers of pyridinedicarboxylic acids, namely, 2,3-pyridinedicarboxylic acid (2,3-PDA), 2,5-pyridinedicarboxylic acid (2,5-PDA) and 2,6-pyridinedicarboxylic acid (2,6-PDA), were screened using conventional solution cocrystallization technique. Whereas the new phases derived from the amino acid with 2,3-PDA or 2,5-PDA were analyzed using powder X-ray diffraction and thermal analysis techniques, the crystalline phase synthesized from 2,6-substituted isomer was further characterized by single crystal X-ray diffraction. Structural analysis revealed that the amino acid exists in the zwitterionic form interacting with the neutral 2,6-PDA by strong intermolecular hydrogen bonding. The components in the co-crystal self-assemble leading to a three dimensional hydrogen bonded closed packed network structure. Isothermal calorimetric titration showed that among the three isomers, 2,6-PDA showed relatively strong binding interaction towards the amino acid in water at 298 K. All the crystals exhibit marginal quenching of fluorescence properties of L-tryptophan in the solid state.

  11. Profiling of the molecular weight and structural isomer abundance of macroalgae-derived phlorotannins. (United States)

    Heffernan, Natalie; Brunton, Nigel P; FitzGerald, Richard J; Smyth, Thomas J


    Phlorotannins are a group of complex polymers of phloroglucinol (1,3,5-trihydroxybenzene) unique to macroalgae. These phenolic compounds are integral structural components of the cell wall in brown algae, but also play many secondary ecological roles such as protection from UV radiation and defense against grazing. This study employed Ultra Performance Liquid Chromatography (UPLC) with tandem mass spectrometry to investigate isomeric complexity and observed differences in phlorotannins derived from macroalgae harvested off the Irish coast (Fucus serratus, Fucus vesiculosus, Himanthalia elongata and Cystoseira nodicaulis). Antioxidant activity and total phenolic content assays were used as an index for producing phlorotannin fractions, enriched using molecular weight cut-off dialysis with subsequent flash chromatography to profile phlorotannin isomers in these macroalgae. These fractions were profiled using UPLC-MS with multiple reaction monitoring (MRM) and the level of isomerization for specific molecular weight phlorotannins between 3 and 16 monomers were determined. The majority of the low molecular weight (LMW) phlorotannins were found to have a molecular weight range equivalent to 4-12 monomers of phloroglucinol. The level of isomerization within the individual macroalgal species differed, resulting in substantially different numbers of phlorotannin isomers for particular molecular weights. F. vesiculosus had the highest number of isomers of 61 at one specific molecular mass, corresponding to 12 phloroglucinol units (PGUs). These results highlight the complex nature of these extracts and emphasize the challenges involved in structural elucidation of these compounds.

  12. Thermal decomposition of 1-pentanol and its isomers: a theoretical study. (United States)

    Zhao, Long; Ye, Lili; Zhang, Feng; Zhang, Lidong


    Pentanol is one of the promising "next generation" alcohol fuels with high energy density and low hygroscopicity. In the present work, dominant reaction channels of thermal decomposition of three isomers of pentanol: 1-pentanol, 2-methyl-1-butanol, and 3-methyl-1-butanol were investigated by CBS-QB3 calculations. Subsequently, the temperature- and pressure-dependent rate constants for these channels were computed by RRKM/master equation simulations. The difference between the thermal decomposition behavior of pentanol and butanol were discussed, while butanol as another potential alternative alcohol fuel has been extensively studied both experimentally and theoretically. Rate constants of barrierless bond dissociation reactions of pentanol isomers were treated by the variational transition state theory. The comparison between various channels revealed that the entropies of variational transition states significantly impact the rate constants of pentanol decomposition reactions. This work provides sound quality kinetic data for major decomposition channels of three pentanol isomers in the temperature range of 800-2000 K with pressure varying from 7.6 to 7.6 × 10(4) Torr, which might be valuable for developing detailed kinetic models for pentanol combustion.

  13. Reaction dynamics of Cl + butanol isomers by crossed-beam sliced ion imaging. (United States)

    Estillore, Armando D; Visger-Kiefer, Laura M; Suits, Arthur G


    Butanol is now prominent among the prototype renewable biofuels. We have studied oxidation of a variety of butanol isomers under single collision conditions using chlorine atom as the oxidizing agent to gain detailed insight into the energetics and dynamics of these reactions. The interaction of chlorine atom radicals with butanol isomers: n-butanol, iso-butanol, sec-butanol, and tert-butanol have been studied by crossed-beam dc slice ion imaging techniques. The hydroxybutyl radicals generated from the H-abstraction processes were probed by single photon ionization using an F2 excimer laser. After background subtraction and density-to-flux correction of the raw images, translational energy distribution and product angular distributions were generated. At low collision energy, the hydroxyalkyl products are backscattered with respect to the alcohol beam and the scattering shifts to the forward direction as the collision energy is increased. The translational energy distributions are reminiscent to that of Cl + pentane reactions we studied earlier, i.e. a sharp forward peak -80% of the collision energy appears at the high collision energy. Isomer-specific details of the reactions will be discussed.

  14. Profiling of the Molecular Weight and Structural Isomer Abundance of Macroalgae-Derived Phlorotannins (United States)

    Heffernan, Natalie; Brunton, Nigel P.; FitzGerald, Richard J.; Smyth, Thomas J.


    Phlorotannins are a group of complex polymers of phloroglucinol (1,3,5-trihydroxybenzene) unique to macroalgae. These phenolic compounds are integral structural components of the cell wall in brown algae, but also play many secondary ecological roles such as protection from UV radiation and defense against grazing. This study employed Ultra Performance Liquid Chromatography (UPLC) with tandem mass spectrometry to investigate isomeric complexity and observed differences in phlorotannins derived from macroalgae harvested off the Irish coast (Fucus serratus, Fucus vesiculosus, Himanthalia elongata and Cystoseira nodicaulis). Antioxidant activity and total phenolic content assays were used as an index for producing phlorotannin fractions, enriched using molecular weight cut-off dialysis with subsequent flash chromatography to profile phlorotannin isomers in these macroalgae. These fractions were profiled using UPLC-MS with multiple reaction monitoring (MRM) and the level of isomerization for specific molecular weight phlorotannins between 3 and 16 monomers were determined. The majority of the low molecular weight (LMW) phlorotannins were found to have a molecular weight range equivalent to 4–12 monomers of phloroglucinol. The level of isomerization within the individual macroalgal species differed, resulting in substantially different numbers of phlorotannin isomers for particular molecular weights. F. vesiculosus had the highest number of isomers of 61 at one specific molecular mass, corresponding to 12 phloroglucinol units (PGUs). These results highlight the complex nature of these extracts and emphasize the challenges involved in structural elucidation of these compounds. PMID:25603345

  15. Static and Dynamic Electronic (Hyperpolarizabilities of Dimethylnaphthalene Isomers: Characterization of Spatial Contributions by Density Analysis

    Directory of Open Access Journals (Sweden)

    Andrea Alparone


    Full Text Available Static and frequency-dependent electronic (hyperpolarizabilities of the dimethylnaphthalene (DMN isomers were computed in vacuum using the Coulomb-attenuating Density Functional Theory method. The nonlinear optical Second Harmonic Generation (SHG and Electro-Optical Pockels Effect (EOPE were investigated at the characteristic Nd:YAG laser wavelength of 1064 nm. The response electric properties especially the longitudinal polarizability, polarizability anisotropy, and first-order hyperpolarizability are significantly affected by the position of the methyl groups. The SHG and EOPE techniques can be potentially useful to discriminate the ,-DMN isomers (2,6-DMN < 2,7-DMN < 2,3-DMN as well as the ,-DMN isomers (1,5-DMN < 1,4-DMN < 1,8-DMN. The (hyperpolarizability differences among the investigated DMNs were elucidated through density analysis calculations. The predicted polarizabilities exhibit good linear relationships with the experimental first-order biomass-normalized rate coefficient, a physicochemical property connected to the rates of biodegradation processes of polycyclic aromatic hydrocarbons.

  16. Anionic fructose-related conformational and positional isomers assigned through PES experiments and DFT calculations. (United States)

    Zeng, Zhen; Bernstein, Elliot R


    Gas phase, isolated fructose anionic species, fructose(-), (fructose-H)(-), (fructose-OH)(-), and (fructose-H2O)(-), are investigated employing anionic photoelectron spectroscopy (PES) combined with density functional theory (DFT) calculations. The PES vertical detachment energies (VDEs) for these anions are determined and, based on these experimental values, their calculated anionic structures are assigned. Generation of these four species through the matrix assisted laser desorption ionization (MALDI) process is sample desorption substrate dependent. The parent anion fructose(-) exists as a single, dominant open chain structure in the gas phase, with substrate dependent specific conformational isomers. (Fructose-H)(-) and (fructose-OH)(-) are mainly produced from the laser ablation process rather than from fragmentation reaction pathways associated with the parent anion species. Both conformational and positional isomers are identified in the gas phase for these latter anions. (Fructose-H2O)(-) has two types of positional isomers, both of which contribute to two different components of the observed PES feature. The fixed positions for losing an OH group and an H atom, in addition to thermodynamic calculations, provide reaction pathways for generating a dehydration product (open chain structures) from the parent anion (open chain and furanose structures), further demonstrating the active nature of fructose upon capturing an extra electron.

  17. Supplementation with CLA: isomer incorporation into serum lipids and effect on body fat of women. (United States)

    Petridou, Anatoli; Mougios, Vassilis; Sagredos, Angelos


    Animal studies have suggested that CLA, a natural component of meat and dairy products, may confer beneficial effects on health. However, human studies using supplementation with CLA have produced contradictory results. The aim of the present study was to further investigate the effect of CLA supplementation on human body fat, serum leptin, and serum lipids, as well as the incorporation of CLA isomers into serum lipids classes. Sixteen young healthy nonobese sedentary women received 2.1 g of CLA (divided equally between the cis,trans-9,11 and trans,cis-10,12 isomers) daily for 45 d and placebo for 45 d in a randomized double-blind crossover design. Body fat was estimated (by measurement of skinfold thickness at 10 sites), and blood was sampled at the beginning, middle, and end of the entire intervention period; an additional blood sample was obtained 2 wk thereafter. No significant differences in energy, carbohydrate, lipid, or protein intake existed between the CLA and placebo intake periods. No significant differences were found in body fat or serum leptin, TAG, total cholesterol, HDL-cholesterol, and alanine aminotransferase between CLA and placebo. The CLA isomer content of serum TAG, phospholipids, and total lipids increased 2-5 times with CLA supplementation (P lipids. These data indicate that supplementation with 2.1 g of CLA daily for 45 d increased its levels in blood but had no effect on body composition or the lipidemic profile of nonobese women.

  18. Decay spectroscopy of 160Sm: The lightest four-quasiparticle K isomer

    Directory of Open Access Journals (Sweden)

    Z. Patel


    Full Text Available The decay of a new four-quasiparticle isomeric state in 160Sm has been observed using γ-ray spectroscopy at the RIBF, RIKEN. The four-quasiparticle state is assigned a 2π⊗2ν π52−[532], π52+[413], ν52−[523], ν72+[633] configuration. The half-life of this (11+ state is measured to be 1.8(4 μs. The (11+ isomer decays into a rotational band structure, based on a (6− ν52−[523]⊗ν72+[633] bandhead, consistent with the gK−gR values. This decays to a (5− two-proton quasiparticle state, which in turn decays to the ground state band. Potential energy surface and blocked-BCS calculations were performed in the deformed midshell region around 160Sm. They reveal a significant influence from β6 deformation and that 160Sm is the best candidate for the lightest four-quasiparticle K isomer to exist in this region. The relationship between reduced hindrance and isomer excitation energy for E1 transitions from multiquasiparticle states is considered with the new data from 160Sm. The E1 data are found to agree with the existing relationship for E2 transitions.

  19. Characterization of charge isomers of yeast phosphoglycerate kinase. Evidence for intracellular differences. (United States)

    Arvidsson, L; Schierbeck, B; Larsson-Raźnikiewicz, M


    Three electrophoretic components of phosphoglycerate kinase have been isolated from baker's yeast. The isoionic point of the major component is 7.18 at 10 degrees C. Corresponding values for the minor ones are 6.91 and 7.48, respectively. There is a difference of one charge-unit between the isomers 1 and 2, and between the isomers 2 and 3. The release of component 3 from the yeast cells appears in contrast to the isomers 1 and 2 to be promoted by an organic solvent, thus suggesting this component to be bound to the cell-membrane. The amino-terminal amino acid residue appears to be N-acetylated serine in each of the three cases. The carboxyl-terminal ends seem to be identical also with -(Ala, Leu, Val, Lys)- Ala-Lys as the ultimate sequence. From the circular dichroism spectra the contents of alpha-helix and beta-structure were estimated to 15 and 40-50%, respectively. Factors have been determined for transformation and comparison of the specific activities as determined under the various conditions used at different laboratories.

  20. Nickel(II) dithiocarbamate complexes containing sulforhodamine B as fluorescent probes for selective detection of nitrogen dioxide. (United States)

    Yan, Yan; Krishnakumar, Saarangan; Yu, Huan; Ramishetti, Srinivas; Deng, Lih-Wen; Wang, Suhua; Huang, Leaf; Huang, Dejian


    We synthesized complexes of Ni(II) with dithiocarbamate ligands derived from the ortho and para isomers of sulforhodamine B fluorophores and demonstrated they are highly selective in reactions with nitrogen dioxide (NO2). Compared with the para isomer, the ortho isomer showed a much greater fluorescence increase upon reaction with NO2, which led to oxidation and decomplexation of the dithiocarbamate ligand from Ni(II). We applied this probe for visual detection of 1 ppm NO2 in the gas phase and fluorescence imaging of NO2 in macrophage cells treated with a nitrogen dioxide donor.

  1. Conformational gel analysis and graphics: Measurement of side chain rotational isomer populations by NMR and molecular mechanics

    CERN Document Server

    Haydock, Christopher


    Conformational gel analysis and graphics systematically identifies and evaluates plausible alternatives to the side chain conformations found by conventional peptide or protein structure determination methods. The proposed analysis determines the populations of side chain rotational isomers and the probability distribution of these populations. The following steps are repeated for each side chain of a peptide or protein: first, extract the local molecular mechanics of side chain rotational isomerization from a single representative global conformation; second, expand the predominant set of rotational isomers to include all probable rotational isomers down to those that constitute just a small percentage of the population; and third, evaluate the constraints vicinal coupling constants and NOESY cross relaxation rates place on rotational isomer populations. In this article we apply conformational gel analysis to the cobalt glycyl-leucine dipeptide and detail the steps necessary to generalize the analysis to oth...

  2. Discrimination of eight chloramphenicol isomers by liquid chromatography tandem mass spectrometry in order to investigate the natural occurence of chloramphenicol

    NARCIS (Netherlands)

    Berendsen, B.J.A.; Zuidema, T.; Jong, de J.; Stolker, A.A.M.; Nielen, M.W.F.


    This paper describes the discrimination of eight different isomers of chloramphenicol (CAP), an antibiotic banned for use in food producing animals, by reversed phase and chiral liquid chromatography in combination with tandem mass spectrometric detection. Previously, by liquid chromatography couple

  3. Production of isotopes and isomers with irradiation of Z = 47–50 targets by 23-MeV bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Karamian, S. A., E-mail: [Joint Institute for Nuclear Research (Russian Federation); Carroll, J. J. [US Army Research Laboratory (United States); Aksenov, N. V.; Albin, Yu. A.; Belov, A. G.; Bozhikov, G. A.; Dmitriev, S. N.; Starodub, G. Ya. [Joint Institute for Nuclear Research (Russian Federation)


    The irradiations of Ag to Sn targets by bremsstrahlung generated with 23-MeV electron beams are performed at the MT-25 microtron. Gamma spectra of the induced activities have been measured and the yields of all detected radionuclides and isomers are carefully measured and analyzed. A regular dependence of yields versus changed reaction threshold is confirmed. Many isomers are detected and the suppression of the production probability is observed with growing product spin. Special peculiarities for the isomer-to-ground state ratios were deduced for the {sup 106m}Ag, {sup 108m}Ag, {sup 113m}In, {sup 115m}In, and {sup 123m}Sn isomers. The production of such nuclides as {sup 108m}Ag, {sup 115m}In, {sup 117g}In, and {sup 113m}Cd is of interest for applications, especially when economic methods are available.

  4. Enantioseparation of Dencichine and D-Isomer on L-Cysteine Derivative Phase by Ligand-exchange Chromatography

    Institute of Scientific and Technical Information of China (English)

    Yan Shun MA; Qing Hua MENG; Hong Yu SHI; Yuan De LONG; Tian Bao HUANG


    The enantioseparation of dencichine and its D-isomer was achieved on a novel chiral stationary phase via coating N-(2-hydroxyl-3-octoxyl) propyl-S-benzyl-(L)-cysteine on YWG-C18phase by ligand exchange chromatography.

  5. Solvent effect on the stability and properties of platinum-substituted borirene and boryl isomers: The polarizable continuum model (United States)

    Ghiasi, Reza; Peikari, Ali


    The structure and properties of platinum borirene complex trans-[Cl(PMe3)2Pt{μ-BN(SiMe3)2C=C}Ph] and its isomer the platinum boryl complex trans-[Cl(PMe3)2PtBN(SiMe3)2C≡CPh] were investigated theoretically. The solvent effect on the stability, structural parameters, frontier orbital energies, HOMO-LUMO gaps, and hardness of isomers was investigated using the polarizable continuum model (PCM). It was found that borirene isomer is the most stable isomer in the gas phase and solvent. The calculated results show that the presence of solvent reduces the frontier orbital energy of the studied molecules. Geometries obtained from calculations were used to perform NBO analysis.

  6. Ab initio correlated study of the Al13H- anion: Isomers, their kinetic stability and vertical detachment energies (United States)

    Moc, Jerzy


    We report correlated ab initio calculations for the Al13H- cluster anion isomers, their kinetic stability and vertical detachment energies (VDEs). Of the two most energetically favored anion structures involving H atom in terminal and threefold bridged sites of the icosahedral Al13-, the higher energy ‘threefold bridged' isomer is shown to be of low kinetic stability. Our results are consistent with the recent photoelectron spectroscopy (PE) study of Grubisic et al. who observed two distinct Al13H- isomers, one of them identified as ‘metastable'. The VDE energies computed at the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVDZ level for the ‘terminal' and ‘threefold bridged' Al13H- isomers of 3.21 and 2.32 eV are in good agreement with those determined in the PE study.

  7. Development and validation of a liquid chromatography with mass spectrometry method to determine resveratrol and piceid isomers in beeswax. (United States)

    Ares, Ana M; González, Yolanda; Nozal, María J; Bernal, José L; Higes, Mariano; Bernal, José


    This paper represents the first report of a liquid chromatography coupled to electrospray ionization mass spectrometry method for simultaneously analyzing resveratrol and piceid isomers (cis and trans) in beeswax. An efficient extraction procedure has been proposed (average analyte recoveries were between 89 and 95%); this involved a solid-liquid extraction using a mixture of ethanol and water (80:20, v/v) and a concentration step in a rotary evaporator. The separation of all the compounds was achieved using a C18 column and a mobile phase composed of ammonium formate 0.03 M in water and acetonitrile in gradient elution mode at a flow rate of 1 mL/min. The method was fully validated in terms of selectivity, limits of detection and quantification, linearity, precision, and accuracy. The limits of detection and quantification ranged from 1.0 to 1.7 and 3.5 to 5.5 μg/kg, respectively. Finally, the proposed method was applied to analyze beeswax samples collected from experimental and organic apiaries.

  8. A case of Z/E-isomers elution order inversion caused by cosolvent percentage change in supercritical fluid chromatography. (United States)

    Pokrovskiy, Oleg I; Ustinovich, Konstantin B; Usovich, Oleg I; Parenago, Olga O; Lunin, Valeriy V; Ovchinnikov, Denis V; Kosyakov, Dmitry S


    A case of elution order inversion caused by cosolvent percentage change in supercritical fluid chromatography was observed and investigated in some detail. Z- and E-isomers of phenylisobutylketone oxime experience an elution order reversal on most columns if the mobile phase consists of CO2 and alcohol. At lower percentages of alcohol Z-oxime is retained less, somewhere at 2-5% coelution occurs and at larger cosolvent volume elution order reverses - Z-oxime is eluted later than E-oxime. We suppose inversion with CO2-ROH phases happens due to a shift in balance between two main interactions governing retention. At low ROH percentages stationary phase surface is only slightly covered by ROH molecules so oximes primarily interact with adsorption sites via hydrogen bond formation. Due to intramolecular sterical hindrance Z-oxime is less able to form hydrogen bonds and consequently is eluted first. At higher percentages alcohols occupy most of strong hydrogen bonding sites on silica surface thus leaving non-specific electrostatic interactions predominantly responsible for Z/E selectivity. Z-oxime has a much larger dipole moment than E-oxime and at these conditions it is eluted later. Additional experimental data with CO2-CH3CN, hexane-iPrOH and CHF3-ROH mobile phases supporting this explanation are presented.

  9. Theoretical study of γ-hexachlorocyclohexane and β-hexachlorocyclohexane isomers interaction with surface groups of activated carbon model. (United States)

    Enriquez-Victorero, Carlos; Hernández-Valdés, Daniel; Montero-Alejo, Ana Lilian; Durimel, Axelle; Gaspard, Sarra; Jáuregui-Haza, Ulises


    Activated carbon (AC) is employed in drinking water purification without almost any knowledge about the adsorption mechanism of persistent organic pollutants (POPs) onto it. Hexachlorocyclohexane (HCH) is an organochlorinated contaminant present in water and soils of banana crops production zones of the Caribbean. The most relevant isomers of HCH are γ-HCH and β-HCH, both with great environmental persistence. A theoretical study of the influence of AC surface groups (SGs) on HCH adsorption is done in order to help to understand the process and may lead to improve the AC selection process. A simplified AC model consisting of naphthalene with a functional group was used to assess the influence of SGs over the adsorption process. The Multiple Minima Hypersurface (MMH) methodology was employed to study γ-HCH and β-HCH interactions with different AC SGs (hydroxyl and carboxyl) under different hydration and pH conditions. The results obtained showed that association of HCH with SGs preferentially occurs between the axial protons of HCH and SG's oxygen atom, and the most favorable interactions occurring with charged SGs. An increase in carboxylic SGs content is proposed to enhance HCH adsorption onto AC under neutral pH conditions. Finally, this work presents an inexpensive computer aided methodology for preselecting activated carbon SGs content for the removal of a given compound.

  10. 协调与合作:我国传媒监管模式的过渡选择%Coordination and Cooperation: The Transition Selection of the Media Supervision Model in China

    Institute of Scientific and Technical Information of China (English)

    李红祥; 汤伟斌


    新的传播科技带来新的媒介生态,新的媒介生态需要新的监管模式。目前世界各国正在加速传媒监管模式变革以应对三网融合趋势。不同监管模式适用于不同的传媒经营格局,发挥着不同的效力。我国三网融合刚刚起步,远未进入成熟阶段,建立统一监管模式尚无必要。基于客观现实,我们应在维持分业监管的基础上,采用协调合作机制实现三网融合过程中传媒监管模式的过渡。%New communication technology brings a new media ecology,the new media ecology needs new regulatory model.Many countries are accelerating the reform of media regulation model to deal with the trends of three-network convergence in the world.Different regulatory mode is applicable to different patterns of media operation and plays a different effect.The three-network convergence in China has just started,and it is far from entering the mature stage,and there is no need to establish a unified supervision mode.Based on objective reality,we should use the coordination and cooperation mechanism so as to achieve a perfect transition of media supervision mode in the process of three-network convergence.

  11. Invariant manifolds and collective coordinates

    Energy Technology Data Exchange (ETDEWEB)

    Papenbrock, T. [Centro Internacional de Ciencias, Cuernavaca, Morelos (Mexico); Institute for Nuclear Theory, University of Washington, Seattle, WA (United States); Seligman, T.H. [Centro Internacional de Ciencias, Cuernavaca, Morelos (Mexico); Centro de Ciencias Fisicas, University of Mexico (UNAM), Cuernavaca (Mexico)


    We introduce suitable coordinate systems for interacting many-body systems with invariant manifolds. These are Cartesian in coordinate and momentum space and chosen such that several components are identically zero for motion on the invariant manifold. In this sense these coordinates are collective. We make a connection to Zickendraht's collective coordinates and present certain configurations of few-body systems where rotations and vibrations decouple from single-particle motion. These configurations do not depend on details of the interaction. (author)

  12. Fundamental Issues Related to the Origin of Melatonin and Melatonin Isomers during Evolution: Relation to Their Biological Functions

    Directory of Open Access Journals (Sweden)

    Dun-Xian Tan


    Full Text Available Melatonin and melatonin isomers exist and/or coexist in living organisms including yeasts, bacteria and plants. The levels of melatonin isomers are significantly higher than that of melatonin in some plants and in several fermented products such as in wine and bread. Currently, there are no reports documenting the presence of melatonin isomers in vertebrates. From an evolutionary point of view, it is unlikely that melatonin isomers do not exist in vertebrates. On the other hand, large quantities of the microbial flora exist in the gut of the vertebrates. These microorganisms frequently exchange materials with the host. Melatonin isomers, which are produced by these organisms inevitably enter the host’s system. The origins of melatonin and its isomers can be traced back to photosynthetic bacteria and other primitive unicellular organisms. Since some of these bacteria are believed to be the precursors of mitochondria and chloroplasts these cellular organelles may be the primary sites of melatonin production in animals or in plants, respectively. Phylogenic analysis based on its rate-limiting synthetic enzyme, serotonin N-acetyltransferase (SNAT, indicates its multiple origins during evolution. Therefore, it is likely that melatonin and its isomer are also present in the domain of archaea, which perhaps require these molecules to protect them against hostile environments including extremely high or low temperature. Evidence indicates that the initial and primary function of melatonin and its isomers was to serve as the first-line of defence against oxidative stress and all other functions were acquired during evolution either by the process of adoption or by the extension of its antioxidative capacity.

  13. The spectroscopy and photochemistry of quinioline structural isomers: (E)- and (Z)-phenylvinylnitrile

    Energy Technology Data Exchange (ETDEWEB)

    Mehta-Hurt, Deepali N.; Korn, Joseph A.; Navotnaya, Polina; Parobek, Alexander P.; Clayton, Rachel M.; Zwier, Timothy S., E-mail: [Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084 (United States)


    In Titan’s atmosphere, photochemical pathways that lead to nitrogen heteroaromatics may incorporate photoisomerization of their structural isomers as a final step. (E)- and (Z)-phenylvinylnitrile ((E)- and (Z)-PVN, C{sub 6}H{sub 5} —CH=CHCN) are structural isomers of quinoline that themselves possess extensive absorptions in the ultraviolet, and thus may engage in such photoisomerization pathways. The present study explores the vibronic spectroscopy and photo-induced isomerization of gas-phase (E)- and (Z)-PVN in the 33,600-35,850 cm{sup −1} region under jet-cooled conditions. The S{sub 0}-S{sub 1} origins for (E)- and (Z)-PVN have been identified at 33 827 cm{sup −1} and 33 707 cm{sup −1}, respectively. Isomer-specific UV-UV hole-burning and UV depletion spectra reveal sharp vibronic structure that extends over almost 2000 cm{sup −1}, with thresholds for fast non-radiative decay identified by a comparison between hole-burning and UV depletion spectra. Dispersed fluorescence spectra of the two isomers enable the assignment of many low frequency transitions in both molecules, aided by harmonic frequency calculations (B3LYP/6-311++G(d,p)) and a comparison with the established spectroscopy of phenylvinylacetylene, the ethynyl counterpart to PVN. Both isomers are proven to be planar in both the S{sub 0} ground and S{sub 1} electronic excited states. (E)-PVN exhibits extensive Duschinsky mixing involving out-of-plane modes whose frequencies and character change significantly in the ππ{sup ∗} transition, which modulates the degree of single- and double-bond character along the vinylnitrile substituent. This same mixing is much less evident in (Z)-PVN. The spectroscopic characterization of (E)- and (Z)-PVN served as the basis for photoisomerization experiments using ultraviolet hole-filling spectroscopy carried out in a reaction tube affixed to the pulsed valve. Successful interconversion between (E) and (Z)-PVN was demonstrated via ultraviolet hole

  14. An experimental and kinetic modeling study of combustion of isomers of butanol

    Energy Technology Data Exchange (ETDEWEB)

    Grana, Roberto; Frassoldati, Alessio; Faravelli, Tiziano; Ranzi, Eliseo [Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, Milano (Italy); Niemann, Ulrich; Seiser, Reinhard; Cattolica, Robert; Seshadri, Kalyanasundaram [Department of Mechanical and Aerospace Engineering, University of California at San Diego, La Jolla, CA 92093-0411 (United States)


    A kinetic model is developed to describe combustion of isomers of butanol - n-butanol (n-C{sub 4}H{sub 9}OH), sec-butanol (sec-C{sub 4}H{sub 9}OH), iso-butanol (iso-C{sub 4}H{sub 9}OH), and tert-butanol (tert-C{sub 4}H{sub 9}OH). A hierarchical approach is employed here. This approach was previously found to be useful for developing detailed and semi-detailed mechanism of oxidation of various hydrocarbon fuels. This method starts from lower molecular weight compounds of a family of species and proceeds to higher molecular weight compounds. The pyrolysis and oxidation mechanisms of butanol isomers are similar to those for hydrocarbon fuels. Here, the development of the complete set of the primary propagation reactions for butanol isomers proceeds from the extension of the kinetic parameters for similar reactions already studied and recently revised for ethanol, n-propanol and iso-propanol. A detailed description leading to evaluation of rate constants for initiation reactions, metathesis reactions, decomposition reactions of alkoxy radicals, isomerization reactions, and four-center molecular dehydration reactions are given. Decomposition and oxidation of primary intermediate products are described using a previously developed semi-detailed kinetic model for hydrocarbon fuels. The kinetic mechanism is made up of more than 7000 reactions among 300 species. The model is validated by comparing predictions made using this kinetic model with previous and new experimental data on counterflow non-premixed flames of n-butanol and iso-butanol. The structures of these flames were measured by removing gas samples from the flame and analyzing them using a gas chromatograph. Temperature profiles were measured using coated thermocouples. The flame structures were measured under similar conditions for both fuels to elucidate the similarities and differences in combustion characteristics of the two isomers. The profiles measured include those of butanol, oxygen, carbon dioxide

  15. Identification of structurally closely related monosaccharide and disaccharide isomers by PMP labeling in conjunction with IM-MS/MS. (United States)

    Yang, Hongmei; Shi, Lei; Zhuang, Xiaoyu; Su, Rui; Wan, Debin; Song, Fengrui; Li, Jinying; Liu, Shuying


    It remains particularly difficult for gaining unambiguous information on anomer, linkage, and position isomers of oligosaccharides using conventional mass spectrometry (MS) methods. In our laboratory, an ion mobility (IM) shift strategy was employed to improve confidence in the identification of structurally closely related disaccharide and monosaccharide isomers using IMMS. Higher separation between structural isomers was achieved using 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization in comparison with phenylhydrazine (PHN) derivatization. Furthermore, the combination of pre-IM fragmentation of PMP derivatives provided sufficient resolution to separate the isomers not resolved in the IMMS. To chart the structural variation observed in IMMS, the collision cross sections (CCSs) for the corresponding ions were measured. We analyzed nine disaccharide and three monosaccharide isomers that differ in composition, linkages, or configuration. Our data show that coexisting carbohydrate isomers can be identified by the PMP labeling technique in conjunction with ion-mobility separation and tandem mass spectrometry. The practical application of this rapid and effective method that requires only small amounts of sample is demonstrated by the successful analysis of water-soluble ginseng extract. This demonstrated the potential of this method to measure a variety of heterogeneous sample mixtures, which may have an important impact on the field of glycomics.

  16. The antiproliferative effects of biologically active isomers of conjugated linoleic acid on human colorectal and prostatic cancer cells. (United States)

    Palombo, John D; Ganguly, Aniruddha; Bistrian, Bruce R; Menard, Michael P


    The antiproliferative effects of two commercial preparations of conjugated linoleic acid (CLA) and their constituent isomers, cis-9, trans-11 (c9,t11)-CLA, c9,c11-CLA, and t10,c12-CLA, were determined in vitro using human colorectal (HT-29, MIP-101) and prostate (PC-3) carcinoma cells adapted to serum-free medium. The antiproliferative effects of the preparations were dependent upon the type and concentration of CLA isomer present. The t10,c12-CLA isomer exhibited the greatest potency against colorectal cancer proliferation, and the c9,t11 and t10,c12 isomers were moderately effective against prostate cancer. The t10,c12 isomer induced caspase-dependent apoptosis in MIP-101 and PC-3 cells. The results are the first to demonstrate that physiologic levels of two CLA preparations, their constituent isomers, and the c9,t11-CLA elongation product, c11,t13-conjugated eicosadienoic acid, induce dose-dependent inhibitory effects on cancer proliferation in vitro. Novel CLA preparations may prove effective as chemopreventive supplements for individuals at risk of or diagnosed with colorectal or prostate cancer.

  17. Tangerine tomatoes increase total and tetra-cis-lycopene isomer concentrations more than red tomatoes in healthy adult humans. (United States)

    Burri, Betty Jane Burri; Chapman, Mary H; Neidlinger, Terry R; Seo, Jung S; Ishida, Betty K


    Lycopene, or the foods that contain it, may prevent prostate cancer. Studies suggest that some cis-lycopene isomers are more bioavailable than the trans-lycopene isomer. We hypothesized that tangerine tomatoes, which predominantly contain the tetra-cis isomer, should be a good source of bioavailable lycopene. We fed lunches containing 300 g tangerine or red tomato sauce per day to 21 healthy adults in a double-blind crossover design. We collected blood at baseline and after each treatment and washout period. We measured tetra-cis, other cis, and trans lycopene, as well as other carotenoids, by reversed-phase high-performance liquid chromatography. Both tomato sauces increased lycopene concentrations in blood, but the tangerine tomato sauce caused a greater increase of total and tetra-cis-lycopene. The cis isomer(s) may also have facilitated absorption of the trans-lycopene isomer. Indices of oxidative damage decreased as serum lycopene concentrations increased. Our results suggest that total lycopene concentrations can be increased by substituting tetra-cis-lycopene-rich tangerine tomatoes for common red tomatoes in the diet.

  18. Polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) isomer patterns from municipal waste combustion: formation mechanism fingerprints. (United States)

    Ryu, Jae-Yong; Choi, Kum-Chan; Mulholland, James A


    Polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) byproducts can be formed in combustion systems by a variety of mechanisms. While total PCDD/F emissions and, to a lesser extent, homologue distributions from incinerators have been found to vary widely depending on combustion conditions, PCDD/F isomer distributions do not. Formation mechanisms can be grouped into two general categories: condensation of precursors, such as chlorinated phenols, and formation from particulate carbon, termed de novo synthesis. In addition to these mechanisms, chlorination and dechlorination reactions may affect isomer patterns. In this work, isomer patterns from field and laboratory municipal waste combustion samples are compared with computed thermodynamic distributions and those from the following experimental investigations: both gas-phase and metal-catalyzed condensation of chlorinated phenols, chlorination of dibenzo-p-dioxin and dibenzofuran, and dechlorination of octachlorodibenzo-p-dioxin and octachlorodibenzofuran. PCDD/F isomer patterns produced by different formation mechanisms in controlled experiments are distinct and robust, largely unaffected by combustion conditions. PCDD isomer patterns from municipal waste combustion are most similar to those produced by CuCl(2)-catalyzed phenol condensation from 10 chlorinated phenols. PCDF isomer patterns are most similar to those produced by chlorination and dechlorination.


    Directory of Open Access Journals (Sweden)



    Full Text Available Coordination is the management of dependencies between activities. The purpose of coordination is to achieve collectively goals that individual actors cannot meet. Coordination within a supply chain is strategic responses to the problems that arise from inter – organizational dependencies within the chain. Given the increasing importance of inventory management and cost reduction to be gained through supply chain coordination, the challenge to an organization is how to select the appropriate coordination mechanism to benefit all the players of a supply chain.The present study proposes a model to study and analyze the benefit of coordinating supply chaininventories through the use of common replenishment time periods. It investigates the coordination of orderquantities amongst the players in a three level supply chain with a centralized decision process. The first level ofsupply chain consists of multiple buyers, the second level of a single manufacturer, and the third level consistsof multiple suppliers. Each supplier supplies one or more items required in the manufacture of the productproduced. When players in the supply chain agree to coordinate, it is possible to have some of the playersbenefiting more than others in the chain. Under the proposed strategy, the manufacturer specifies commonreplenishment periods and requires all buyers to replenish only at those time periods. To effect the coordinationmanufacturer offers a price discount to entice the buyers to accept this strategy. The model developed in thiswork guarantees that the local costs for the players either remain the same as before coordination, or decrease asa result of coordination. A mathematical model is developed, and numerical study is conducted to evaluate thebenefit of the proposed coordinated theory.

  20. Coordination Control Of Complex Machines

    NARCIS (Netherlands)

    J.C.M. Baeten; B. van Beek; J. Markovski; L.J.A.M. Somers


    Control and coordination are important aspects of the development of complex machines due to an ever-increasing demand for better functionality, quality, and performance. In WP6 of the C4C project, we developed a synthesis-centric systems engineering framework suitable for supervisory coordination o