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101.
Fortier S Kaltsoyannis N Wu G Hayton TW 《Journal of the American Chemical Society》2011,133(36):14224-14227
Treatment of the U(III)-ylide adduct U(CH(2)PPh(3))(NR(2))(3) (1, R = SiMe(3)) with TEMPO generates the U(V) oxo metallacycle [Ph(3)PCH(3)][U(O)(CH(2)SiMe(2)NSiMe(3))(NR(2))(2)] (2) via O-atom transfer, in good yield. Oxidation of 2 with 0.85 equiv of AgOTf affords the neutral U(VI) species U(O)(CH(2)SiMe(2)NSiMe(3))(NR(2))(2) (3). The electronic structures of 2 and 3 are investigated by DFT analysis. Additionally, the nucleophilicity of the oxo ligands in 2 and 3 toward Me(3)SiI is explored. 相似文献
102.
The geometric structures of gas-phase Sr(2+) hydrates are calculated quantum chemically by using hybrid (B3LYP) and meta-GGA (TPSS) density functional theory, and a range of thermodynamic data (including sequential bond enthalpies, entropies and free energies for the reactions Sr(2+)(H(2)O)(n-1)+H(2)O→Sr(2+)(H(2)O)(n)) are shown to be in excellent agreement with experiment. When the number of coordinating water molecules exceeds six, such that water begins to occupy the second solvation shell, it is found that detailed analysis based on both geometrical and conformational entropy is required in order to confidently identify the experimentally observed structures. The significant increase in coordination number observed experimentally between the gas- and aqueous-phase species is successfully reproduced, as is the first solvation shell geometry. Inaccurate second shell geometries imply that larger model systems may be required to achieve agreement with experiment. Candidate species for on-going computational studies of the interaction of hydrated Sr(2+) with brucite surfaces have been identified. 相似文献
103.
Dimitrios P. Nikolelis Nikolas Psaroudakis Antonis I. Michaloliakos Georgia-Paraskevi Nikoleli Michael Scoullos 《Central European Journal of Chemistry》2013,11(2):320-323
An electrochemical biosensor based on a supported polymerized lipid film with incorporated sheep anti-3,3′,4,4′ tetrachlorobiphenyl (PCB congener 77) antibody using flow injection analysis was developed. The polymerized lipid film contained 85% (w/w) dipalmitoylphosphatidylcholine (DPPC) and 15% (w/w) dipalmitoylphosphatidic acid (DPPA), methacrylic acid, ethylene glycol dimethacrylate, AIBN and sheep anti-congener 77 antiserum. Congener 77 was injected into flowing carrier electrolyte and the flow stopped to detect the antigen. These membranes gave only a single transient proportional to log [congener 77] from 10?8 to 10?5 M, with a detection limit of ca. 10?8 M. A membrane containing 35% (w/w) DPPA was used to examine regeneration. The maximum number of cycles was about 5. 相似文献
104.
The Development of Highly Sensitive and Selective Immunosensor Based on Antibody Immobilized ZnO Nanorods for the Detection of D‐Dimer
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Zafar H. Ibupoto Nikolaos Mitrou Georgia‐Paraskevi Nikoleli Dimitrios P. Nikolelis Magnus Willander Nikolas Psaroudakis 《Electroanalysis》2014,26(2):292-298
ZnO nanorods were grown on gold coated glass substrate by low temperature aqueous chemical growth method. Scanning electron microscopy (SEM) and X‐ray diffraction (XRD) techniques were used for the characterization of ZnO nanorods. ZnO nanorods are highly dense, uniform, well aligned and perpendicular‐oriented to the substrate. ZnO nanorods exhibited good crystal quality. The well aligned ZnO nanorods were potentially used for the development of selective and sensitive immunosensor for the detection of D‐dimer by immobilizing antibody on stabilized lipid films. The ZnO nanorods based immunosensor responded to a wide range of D‐dimer concentrations with fast response time of ca. 20 s. 相似文献
105.
A Selective Immunosensor for D‐dimer Based on Antibody Immobilized on a Graphene Electrode with Incorporated Lipid Films
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Georgia‐Paraskevi Nikoleli Dimitrios P. Nikolelis Nikolaos Tzamtzis Nikolas Psaroudakis 《Electroanalysis》2014,26(7):1522-1527
The present article describes a miniaturized potentiometric D‐dimer biosensor on graphene nanosheets with incorporated lipid films. The graphene electrode was used for the development of a very selective and sensitive immunosensor for the detection of D‐dimer by immobilizing the mouse anti human D‐dimer antibody on stabilized lipid films. The immunosensor responded for the wide range of D‐dimer concentrations with fast response time of ca. 15 s. The presented potentiometric D‐dimer biosensor is easy to construct and exhibits good reproducibility, reusability, selectivity, rapid response times, long shelf life and high sensitivity of ca. 59 mV/decade over the D‐dimer logarithmic concentration range from 10?6 μg/L to 10?3 μg/L. 相似文献
106.
107.
Evans WJ Lee DS Ziller JW Kaltsoyannis N 《Journal of the American Chemical Society》2006,128(43):14176-14184
The [Z(2)Ln(THF)](2)(mu-eta(2)():eta(2)()-N(2)) complexes (Z = monoanionic ligand) generated by reduction of dinitrogen with trivalent lanthanide salts and alkali metals are strong reductants in their own right and provide another option in reductive lanthanide chemistry. Hence, lanthanide-based reduction chemistry can be effected in a diamagnetic trivalent system using the dinitrogen reduction product, [(C(5)Me(5))(2)(THF)La](2)(mu-eta(2)():eta(2)()-N(2)), 1, readily obtained from [(C(5)Me(5))(2)La][BPh(4)], KC(8), and N(2). Complex 1 reduces phenazine, cyclooctatetraene, anthracene, and azobenzene to form [(C(5)Me(5))(2)La](2)[mu-eta(3):eta(3)-(C(12)H(8)N(2))], 2, (C(5)Me(5))La(C(8)H(8)), 3, [(C(5)Me(5))(2)La](2)[mu-eta(3):eta(3)-(C(14)H(10))], 4, and [(C(5)Me(5))La(mu-eta(2)-(PhNNPh)(THF)](2), 5, respectively. Neither stilbene nor naphthalene are reduced by 1, but 1 reduces CO to make the ketene carboxylate complex {[(C(5)Me(5))(2)La](2)[mu-eta(4)-O(2)C-C=C=O](THF)}(2), 6, that contains CO-derived carbon atoms completely free of oxygen. 相似文献
108.
Nikolas Isely Miles Lamare Craig Marshall Mike Barker 《Photochemistry and photobiology》2009,85(5):1168-1176
Gene expression of the DNA repair enzyme, photolyase (E.C. 4.1.99.3) was examined in the gonads, eggs, embryos and larval stages of the Antarctic sea urchin, Sterechinus neumayeri . Partial sequencing of the gene revealed two highly conserved regions, including a 300 bp region representing the binding site for the cofactor flavin adenine dinucleotide. The second 1200 bp region, likely representing a second light-harvesting cofactor binding site, was identified in a second sea urchin species, Strongylocentrotus frascicanus . Probes for photolyase were developed from the shorter sequence, and expression in sea urchin developmental tissue and stages, and in response to in situ exposure to ultraviolet radiation was quantified using PCR and RT-qPCR, with concentrations of photolyase normalized to actin concentrations. Photolyase was expressed in all tissues and developmental stages examined. In controlled field-based experiments in McMurdo Sound, Antarctica, we found evidence of both constitutive expression of photolyase and induction in response to in situ exposure of embryos to UV-R. Induction of photolyase was observed in response to greater ambient UV-R (such as shallower water depths or sea ice-free regions). 相似文献
109.
Yardibi T Li J Stoica P Zawodny NS Cattafesta LN 《The Journal of the Acoustical Society of America》2010,127(5):2920-2931
Microphone arrays are commonly used for noise source localization and power estimation in aeroacoustic measurements. The delay-and-sum (DAS) beamformer, which is the most widely used beamforming algorithm in practice, suffers from low resolution and high sidelobe level problems. Therefore, deconvolution approaches, such as the deconvolution approach for the mapping of acoustic sources (DAMAS), are often used for extracting the actual source powers from the contaminated DAS results. However, most deconvolution approaches assume that the sources are uncorrelated. Although deconvolution algorithms that can deal with correlated sources, such as DAMAS for correlated sources, do exist, these algorithms are computationally impractical even for small scanning grid sizes. This paper presents a covariance fitting approach for the mapping of acoustic correlated sources (MACS), which can work with uncorrelated, partially correlated or even coherent sources with a reasonably low computational complexity. MACS minimizes a quadratic cost function in a cyclic manner by making use of convex optimization and sparsity, and is guaranteed to converge at least locally. Simulations and experimental data acquired at the University of Florida Aeroacoustic Flow Facility with a 63-element logarithmic spiral microphone array in the absence of flow are used to demonstrate the performance of MACS. 相似文献
110.
Xinmin Cao Jason A. Stoke Jian Li Nikolas J. Podraza Wenhui Du Xiesen Yang Dinesh Attygalle Xianbo Liao Robert W. Collins Xunming Deng 《Journal of Non》2008,354(19-25):2397-2402
In this study, we have developed and applied deposition phase diagrams in the plane of the bulk layer thickness db and the H2-dilution ratio R = [H2]/[Si2H6] for Si:H materials deposited by 70 MHz VHF PECVD from [H2] + [Si2H6] mixed gases on c-Si/(native-oxide)/n-layer substrates. To establish the phase diagrams, series of Si:H depositions having different R values over the range of 60–150 were measured in real time using a rotating-compensator multichannel ellipsometer. Using phase diagram concepts for guidance, we have fabricated high efficiency single-junction nc-Si:H n–i–p solar cells with ~3 Å/s intrinsic layers using the VHF PECVD process. We have found that the nc-Si:H solar cells with the best performance are obtained by incorporating i-layers deposited in the single-phase nanocrystalline silicon regime near the transition boundary to mixed-phase (a + nc)-Si:H. Applying insights from real time spectroscopic ellipsometry moreover, we have investigated in detail the effects of the phase of the underlying n-layer on the phase evolution of the overdeposited Si:H i-layer and on the overall device performance. With the strategy developed here, a stabilized efficiency of η = 9.46% (Voc = 0.516 V, Jsc = 24.65 mA/cm2, FF = 0.744) has been achieved for nc-Si:H solar cells (0.25 cm2 in active area) fabricated with an i-layer deposition rate of ~2.2 Å/s. 相似文献