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- Shi Xue Dou (7)
- Antal Jakli (6)
- Stephen Blanksby (4)
- Adam Trevitt (3)
- Dr Yanguang Yu (3)
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- Jianli Wang (3)
- Oleg Lavrentovich (3)
- Professor Brian Cullis (3)
- Associate Professor Kashem Muttaqi (2)
- Bela G. Fejer (2)
- Berwyck L. J. Poad (2)
- Gordon Wallace (2)
- Juana Vivó Acrivos (2)
- Satyendra Kumar (2)
- Danielle Skropeta (1)
- Dr Alison Smith (1)
- Heath Ecroyd (1)
- J. A. Aquilina (1)
- Liang-Chy Chien (1)
- Mark R Wilson (1)
- Philip J. Bos (1)
- Professor Jacqui Ramagge (1)
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Articles 1 - 30 of 52
Full-Text Articles in Physical Sciences and Mathematics
Pressure Induced Magneto-Structural Phase Transitions In Layered Rmn2x2 Compounds (Invited), Shane Kennedy, Jianli Wang, Stewart Campbell, Michael Hofmann, S X. Dou
Pressure Induced Magneto-Structural Phase Transitions In Layered Rmn2x2 Compounds (Invited), Shane Kennedy, Jianli Wang, Stewart Campbell, Michael Hofmann, S X. Dou
Shi Xue Dou
We have studied a range of pseudo-ternaries derived from the parent compound PrMn2 Ge 2, substituting for each constituent element with a smaller one to contract the lattice. This enables us to observe the magneto-elastic transitions that occur as the Mn-Mn nearest neighbour distance is reduced and to assess the role of Pr on the magnetism. Here, we report on the PrMn2 Ge 2−xSix, Pr1−xYxMn2 Ge 2, and PrMn2−xFex Ge 2 systems. The pressure produced by chemical substitution in these pseudo-ternaries is inherently non-uniform, with local pressure variations dependent on the local atomic distribution. We find that concentrated chemical substitution …
Cell Attachment And Proliferation On High Conductivity Pedot-Glycol Composites Produced By Vapour Phase Polymerisation, Elise M. Stewart, Manrico Fabretto, Mischa Mueller, Paul J. Molino, Hans J. Griesser, Robert D. Short, Gordon G. Wallace
Cell Attachment And Proliferation On High Conductivity Pedot-Glycol Composites Produced By Vapour Phase Polymerisation, Elise M. Stewart, Manrico Fabretto, Mischa Mueller, Paul J. Molino, Hans J. Griesser, Robert D. Short, Gordon G. Wallace
Gordon Wallace
High conductivity poly(3,4-ethylene dioxythiophene) (PEDOT) was synthesised using vacuum vapour phase polymerization (VVPP). The process produces PEDOT composites which incorporate glycol within the polymer. To assess biocompatibility, a suite of analytical techniques were utilised in an effort to characterise the level of glycol present and its impact on cell attachment and proliferation. A small decrease in fibroblast cell attachment and proliferation was observed with increasing glycol content within the PEDOT composite. Keratinocyte cell attachment and proliferation by comparison showed an increase. As such, the results herein indicate that cell attachment and proliferation depends on the individual cell lines used and …
Magnetic Phase Transitions And Entropy Change In Layered Ndmn1.7cr0.3si2, M F. Md Din, Jianli Wang, S J. Campbell, A J. Studer, M Avdeev, S J. Kennedy, Q F. Gu, R Zeng, S X. Dou
Magnetic Phase Transitions And Entropy Change In Layered Ndmn1.7cr0.3si2, M F. Md Din, Jianli Wang, S J. Campbell, A J. Studer, M Avdeev, S J. Kennedy, Q F. Gu, R Zeng, S X. Dou
Shi Xue Dou
A giant magnetocaloric effect has been observed around the Curie temperature, TC ∼ 42 K, in NdMn1.7Cr0.3Si2 with no discernible thermal and magnetic hysteresis losses. Below 400 K, three magnetic phase transitions take place around 380 K, 320 K and 42 K. Detailed high resolution synchrotron and neutron powder diffraction (10-400 K) confirmed the magnetic transitions and phases as follows: TN intra ∼ 380 K denotes the transition from paramagnetism to intralayer antiferromagnetism (AFl), TN inter ∼ 320 K represents the transition from the AFl structure to the canted antiferromagnetic spin structure (AFmc), while TC ∼ 42 K denotes the …
Aging Effect Evolution During Ferroelectric-Ferroelectric Phase Transition: A Mechanism Study, Zuyong Feng, Zhenxiang Cheng, Dongqi Shi, S X. Dou
Aging Effect Evolution During Ferroelectric-Ferroelectric Phase Transition: A Mechanism Study, Zuyong Feng, Zhenxiang Cheng, Dongqi Shi, S X. Dou
Shi Xue Dou
Aging can significantly modify the dielectric, piezoelectric, and ferroelectric performance of ferroelectrics. However, little attention has been paid to the aging effect during ferroelectric-ferroelectric phase transitions that is essentially correlated with real applications. In this letter, the authors report the aging effect evolution between two ferroelectric phases in an acceptor-doped piezoceramics. The results show that aging-induced double hysteresis loops were exhibited in different ferroelectric phases, but disappeared during ferroelectric-ferroelectric phase transitions, suggesting the mechanism that the intrinsic restoring force for the reversible switching of domains caused by the alignment of defect dipoles was weakened due to ferroelectric dipole reorientation.
Magnetic Phase Diagram And Correlation Between Metamagnetism And Superconductivity In Ru0.9sr2ycu2.1o7.9, Rashmi Nigam, Shane J. Kennedy, Alexey V. Pan, S X. Dou
Magnetic Phase Diagram And Correlation Between Metamagnetism And Superconductivity In Ru0.9sr2ycu2.1o7.9, Rashmi Nigam, Shane J. Kennedy, Alexey V. Pan, S X. Dou
Shi Xue Dou
The magnetic superconductor Ru0.9Sr2YCu2.1O7.9 (Ru-1212Y) has been investigated using neutron diffraction under variable temperature and magnetic field. With the complementary information from magnetization measurements, we propose a magnetic phase diagram T-H for the Ru-1212 system. Uniaxial antiferromagnetic (AFM) order of 1.2μ B/Ru atoms with moments parallel to the c-axis is found below the magnetic transition temperature at ~140 K in the absence of magnetic field. In addition, ferromagnetism (FM) in the ab-plane develops below ~120 K, but is suppressed at lower temperature by superconducting correlations. Externally applied magnetic fields cause Ru-moments to realign from the c-axis to the ab-plane, i.e. …
Solid-State And Solution-Phase Conformations Of Pseudoproline-Containing Dipeptides, James R. Cochrane, Nima Sayyadi, Danielle Skropeta, Peter Turner, Jack K. Clegg, Katrina A. Jolliffe
Solid-State And Solution-Phase Conformations Of Pseudoproline-Containing Dipeptides, James R. Cochrane, Nima Sayyadi, Danielle Skropeta, Peter Turner, Jack K. Clegg, Katrina A. Jolliffe
Danielle Skropeta
The conformations of 14 threonine-derived pseudoproline-containing dipeptides (including four d-allo-Thr derivatives) have been investigated by NMR. In solution, the major conformer observed for all dipeptides is that in which the amide bond between the pseudoproline and the preceding amino acid is cis. For dipeptides in which the N-terminus is protected, the ratio of cis- to trans-conformers does not depend significantly on the side chain of the N-terminal amino acid, or the stereochemistry of the Thr residue. However, for dipeptides bearing a free N-terminus, there are significant differences in the ratios of cis- to trans-conformers depending on the side chain present. …
Coexistence Of Two Colloidal Crystals At The Nematic-Liquid-Crystal-Air Interface, A. B. Nych, V. M. Pergamenshchik, B. I. Lev, V. G. Nazarenko, I. Muševič, M. Škarabot, Oleg Lavrentovich
Coexistence Of Two Colloidal Crystals At The Nematic-Liquid-Crystal-Air Interface, A. B. Nych, V. M. Pergamenshchik, B. I. Lev, V. G. Nazarenko, I. Muševič, M. Škarabot, Oleg Lavrentovich
Oleg Lavrentovich
Glycerol droplets at a nematic-liquid-crystal–air interface form two different lattices—hexagonal and dense quasihexagonal—which are separated by the energy barrier and can coexist. Director distortions around each droplet form an elastic dipole. The first order transition between the two lattices is driven by a reduction of the dipole-dipole repulsion through reorientation of these dipoles. The elastic-capillary attraction is essential for the both lattices. The effect has a many-body origin.
Monte Carlo Simulations Of Stable Point Defects In Hybrid Nematic Films, C. Chiccoli, Oleg Lavrentovich, P. Pasini, C. Zannoni
Monte Carlo Simulations Of Stable Point Defects In Hybrid Nematic Films, C. Chiccoli, Oleg Lavrentovich, P. Pasini, C. Zannoni
Oleg Lavrentovich
Monte Carlo (MC) simulations based exclusively on nearest-neighbor intermolecular interactions reveal the existence of stable long-range deformations and topological defects in a thin nematic film confined between two surfaces with antagonistic (normal and tangential) molecular orientations. Thus the MC technique allows one to describe a delicate balance of bulk elasticity and surface energy usually treated only with macroscopic theories.
Biaxial Nematic Order Induced By Smectic Fluctuations, C. Zhang, S. Chakraborty, T. Ostapenko, Samuel N. Sprunt, Antal Jakli, Jim T. Gleeson
Biaxial Nematic Order Induced By Smectic Fluctuations, C. Zhang, S. Chakraborty, T. Ostapenko, Samuel N. Sprunt, Antal Jakli, Jim T. Gleeson
Antal Jakli
We report on a series of measurements on the microscopic structure and the magneto-optical properties of a calamitic liquid crystalline compound in its nematic phase. Structural studies show the existence of short-range, tilted smectic order consistent with pretransitional effects above an underlying smectic phase. Concomitantly, magneto-optical results exhibit the existence of an optic axis not collinear with the uniaxial director. This apparent biaxial nature is discussed within the context of coupling between the tensor nematic and the smectic order parameters.
Optical Waveguiding In Bent-Core Liquid-Crystal Filaments, Jake Fontana, C. Bailey, Wolfgang Weissflog, I. Janossy, Antal Jakli
Optical Waveguiding In Bent-Core Liquid-Crystal Filaments, Jake Fontana, C. Bailey, Wolfgang Weissflog, I. Janossy, Antal Jakli
Antal Jakli
We demonstrate optical waveguiding in recently discovered free-standing bent-core liquid-crystal filaments. The bent-core liquid-crystal molecules in air self-assemble into a cylindrical geometry that is "solidlike" along the radial direction of the filament and liquid in the axial direction of the filament. These filaments are unique not only because they are fluids, but also because they are anisotropic. For this reason, their waveguiding properties not predictable need to be characterized. The light power transmitted through the filament was found to be independent of temperature from 180 degrees C to near room temperature. Initial defects of newly pulled filaments were found to …
Light-Induced Changes Of Optical And Electrical Properties In Bent-Core Azo Compounds, Antal Jakli, V. Prasad, D.S.S. Rao, Guangxun Liao, I. Janossy
Light-Induced Changes Of Optical And Electrical Properties In Bent-Core Azo Compounds, Antal Jakli, V. Prasad, D.S.S. Rao, Guangxun Liao, I. Janossy
Antal Jakli
We have studied the optical and electrical properties of two bent-core substances with an azo linkage in their cores. Pump-probe laser studies, direct textural observations, and spectrophotometric recordings show an initial decrease of light transmission, which at larger light intensities (similar to 1 mW/mm(2)) is followed by a bleaching. Simultaneously the electrical properties (electric conductivity, antiferroelectric polarization, switching threshold, and switching time) decreased monotonically with increasing light intensities. The monotonic decrease of electrical properties indicates that the darkening and bleaching have the same origin, namely, the photochemical isomerization of the azo linkage from the trans to the cis isomer. The …
Short Pitch Cholesteric Electro-Optical Device Stabilized By Nonuniform Polymer Network, Sang Kim, Liang-Chy Chien
Short Pitch Cholesteric Electro-Optical Device Stabilized By Nonuniform Polymer Network, Sang Kim, Liang-Chy Chien
Liang-Chy Chien
We have developed a method for stabilization of the uniform lying helix (ULH) texture of short pitch cholesterics in an electro-optical device, based on the flexoelectro-optic effect in such a texture. By using a small concentration of photoreactive liquid crystal monomer (less than 5 wt. %) and selecting the illumination conditions, we were able to create a nonuniform polymeric network in the liquid crystal bulk (localized essentially at both substrate surfaces) which stabilized efficiently the amplitude and the phase modulation modes of the device. Most importantly, the effect of the residual birefringence of the polymeric network in the field-unwound state …
Nematic Biaxiality In A Bent-Core Material, Hyungguen Yoon, Shin-Woong Kang, Ronald Y. Dong, Alberto Marini, Kattera A. Suresh, Mohan Srinivasarao, Satyendra Kumar
Nematic Biaxiality In A Bent-Core Material, Hyungguen Yoon, Shin-Woong Kang, Ronald Y. Dong, Alberto Marini, Kattera A. Suresh, Mohan Srinivasarao, Satyendra Kumar
Satyendra Kumar
The results of a recent investigation of the nematic biaxiality in a bent-core mesogen (A131) are in apparent disagreement with earlier claims. Samples of mesogen A131 used in the two studies were investigated with polarized optical microscopy, conoscopy, carbon-13 NMR, and crossover frequency measurements. The results demonstrate that textural changes associated with the growth of biaxial nematic order appear at similar to 149 degrees C. The Maltese cross observed in the conoscopic figure gradually splits into two isogyres at lower temperatures indicating phase biaxiality. Presence of the uniaxial to biaxial nematic phase transition is further confirmed by temperature trends of …
Onset And Evolution Of The Tilted Smectic Antiphase In A Polar Liquid-Crystal Binary Mixture, Yushan Shi, George Nounesis, Satyendra Kumar
Onset And Evolution Of The Tilted Smectic Antiphase In A Polar Liquid-Crystal Binary Mixture, Yushan Shi, George Nounesis, Satyendra Kumar
Satyendra Kumar
High-resolution x-ray diffraction studies of a binary mixture of the n = 8 and n = 10 homologs of alkoxyphenyl nitrobenzoyloxy benzoate DBnONO2 (52.6 mole % DB10ONO2) have been performed at the onset of the tilted smectic antiphase (Sm-C) upon cooling from the smectic-A(1) phase. Fluctuations of the two competing smectic orders are found to be related to monolayer and partial bilayer ordering. With decreasing temperature, the period of the antiphase in-plane modulation increases while the smectic layer normal tilts at an angle of +/-7 degrees with respect to the director. This tilt partially recovers upon the transition to the …
Concerted Ho2 Elimination From Alpha-Aminoalkylperoxyl Free Radicals: Experimental And Theoretical Evidence From The Gas-Phase Nh2 Chco2 - + O2 Reaction, Gabriel Da Silva, Benjamin Kirk, Celli Lloyd, Adam Trevitt, Stephen Blanksby
Concerted Ho2 Elimination From Alpha-Aminoalkylperoxyl Free Radicals: Experimental And Theoretical Evidence From The Gas-Phase Nh2 Chco2 - + O2 Reaction, Gabriel Da Silva, Benjamin Kirk, Celli Lloyd, Adam Trevitt, Stephen Blanksby
Adam Trevitt
We have investigated the gas-phase reaction of the α- aminoacetate (glycyl) radical anion (NH2 •CHCO2−) with O2 using ion trap mass spectrometry, quantum chemistry, and statistical reaction rate theory. This radical is found to undergo a remarkably rapid reaction with O2 to form the hydroperoxyl radical (HO2 •) and an even-electron imine (NHCHCO2−), with experiments and master equation simulations revealing that reaction proceeds at the ion−molecule collision rate. This reaction is facilitated by a low-energy concerted HO2 • elimination mechanism in the NH2CH(OO•)CO2− peroxyl radical. These findings can explain the widely observed free-radical-mediated oxidation of simple amino acids to amides …
Gas-Phase Reactions Of Aryl Radicals With 2-Butyne: An Experimental And Theoretical Investigation Employing The N-Methyl-Pyridinium-4-Yl Radical Cation, Adrian Lam, Cong Li, George Khairallah, Benjamin Kirk, Stephen Blanksby, Adam Trevitt, Uta Wille, Richard O'Hair, Gabriel Da Silva
Gas-Phase Reactions Of Aryl Radicals With 2-Butyne: An Experimental And Theoretical Investigation Employing The N-Methyl-Pyridinium-4-Yl Radical Cation, Adrian Lam, Cong Li, George Khairallah, Benjamin Kirk, Stephen Blanksby, Adam Trevitt, Uta Wille, Richard O'Hair, Gabriel Da Silva
Adam Trevitt
Aromatic radicals form in a variety of reacting gas-phase systems, where their molecular weight growth reactions with unsaturated hydrocarbons are of considerable importance. We have investigated the ion–molecule reaction of the aromatic distonic N-methyl-pyridinium-4-yl (NMP) radical cation with 2-butyne (CH3C≡CCH3) using ion trap mass spectrometry. Comparison is made to high-level ab initio energy surfaces for the reaction of NMP and for the neutral phenyl radical system. The NMP radical cation reacts rapidly with 2-butyne at ambient temperature, due to the apparent absence of any barrier. The activated vinyl radical adduct predominantly dissociates via loss of a H atom, with lesser …
Magnetic Phase Transition In Mnfep0.5as0.4si 0.1, Jianli Wang, Stewart J. Campbell, O Tegus, E Bruck, S X. Dou
Magnetic Phase Transition In Mnfep0.5as0.4si 0.1, Jianli Wang, Stewart J. Campbell, O Tegus, E Bruck, S X. Dou
Jianli Wang
We have carried out a detailed investigation of the magnetic phase transition in MnFeP0.5As0.4Si0.1. Temperature hysteresis has been observed in the variable temperature magnetization curves (Bappl = 0.01 T) with TC W ~ 302 K on warming and TC C ~ 292 K on cooling. The first order nature of this transition in MnFeP0.5As0.4Si0.1 is confirmed by the negative slope obtained from isotherms of M2 versus B/M around the critical temperature. Linear thermal expansion measurements reveal a large volume change, ΔV/V∼8.7×10-3, at the magnetic phase transition and that this magnetovolume effect is suppressed to ΔV/V ∼ 5.5×10-3 in an applied …
Phase Gap In Pseudoternary R1-Yry Mn2x 2-Xxx Compounds, Jianli Wang, S J. Kennedy, S J. Campbell, M Hofmann, S X. Dou
Phase Gap In Pseudoternary R1-Yry Mn2x 2-Xxx Compounds, Jianli Wang, S J. Kennedy, S J. Campbell, M Hofmann, S X. Dou
Jianli Wang
Our neutron diffraction investigation of PrMn2Ge2−xSix reveals a clear separation into two magnetic phases, canted ferromagnetic (Fmc) and antiferromagnetic (AFmc), between x = 1.0 and 1.2 and a commensurate phase gap in the lattice, due to magnetostrictive distortion. This remarkable magnetoelastic phenomenon is driven by a nonuniform atomic distribution on the X site which in turn produces subtle variations in the local lattice and abrupt changes in the Mn-Mn magnetic exchange interaction. Our results show that coexistence of Fmc and AFmc phases depends on lattice parameter, chemical pressure from the rare-earth and metalloid sites, and local lattice strain distributions. We …
Three First Order Magnetic Phase Transitions In Re-Entrant Ferromagnet Prmn1.4fe0.6ge2, Rong Zeng, Jianli Wang, Lin Lu, Wenxian Li, Stewart Campbell, S Dou
Three First Order Magnetic Phase Transitions In Re-Entrant Ferromagnet Prmn1.4fe0.6ge2, Rong Zeng, Jianli Wang, Lin Lu, Wenxian Li, Stewart Campbell, S Dou
Jianli Wang
Three first order magnetic phase transitions (FOMTs) have been detected and evaluated over the temperature range from 5 to 340 K at fields up to 9 T in PrMn1.4Fe0.6Ge2. All three FOMTs, from (with decreasing temperature) an antiferromagnetic (AFl) to a c-axis canted ferromagnetic (Fmc) state, to a c-axis canted antiferromagnetic (AFmc) state, and then to an Fmc state plus an additional Pr-sublattice magnetic contribution (Fmc + F(Pr)), exhibited temperature and field-induced transition features. A interesting phenomenon was observed, in that magnetic field can induce an AFmc to Fmc + F(Pr) transition, and then diminish and finally eliminate the re-entrant …
Magnetic Phase Transition In Mnfep0.5as0.4si 0.1, Jianli Wang, Stewart J. Campbell, O Tegus, E Bruck, S X. Dou
Magnetic Phase Transition In Mnfep0.5as0.4si 0.1, Jianli Wang, Stewart J. Campbell, O Tegus, E Bruck, S X. Dou
Shi Xue Dou
We have carried out a detailed investigation of the magnetic phase transition in MnFeP0.5As0.4Si0.1. Temperature hysteresis has been observed in the variable temperature magnetization curves (Bappl = 0.01 T) with TC W ~ 302 K on warming and TC C ~ 292 K on cooling. The first order nature of this transition in MnFeP0.5As0.4Si0.1 is confirmed by the negative slope obtained from isotherms of M2 versus B/M around the critical temperature. Linear thermal expansion measurements reveal a large volume change, ΔV/V∼8.7×10-3, at the magnetic phase transition and that this magnetovolume effect is suppressed to ΔV/V ∼ 5.5×10-3 in an applied …
Band Structures, Magnetic Properties, And Enhanced Magnetoresistance In The High Pressure Phase Of Gd And Y Doped Two-Dimensional Perovskite Sr2coo4 Compounds, Xiaolin Wang, E Takayama-Muromachi, S X. Dou, Zhenxiang Cheng
Band Structures, Magnetic Properties, And Enhanced Magnetoresistance In The High Pressure Phase Of Gd And Y Doped Two-Dimensional Perovskite Sr2coo4 Compounds, Xiaolin Wang, E Takayama-Muromachi, S X. Dou, Zhenxiang Cheng
Shi Xue Dou
The authors present their studies on the band structures and on the magnetic and magnetotransport properties of the high pressure phase of Sr2-xRExCoO4 [rare earth (RE)=Gd and Y, x=0.1-0.5] compounds which were synthesized by a high pressure and high temperature technique. The authors found that as x increases, the magnetoresistance {(PH-P0)/p0} increases up to -17% at 5 K and 7 T, which is 2.5 times higher than that for undoped Sr2CoO4, although the ferromagnetic transition drops from 255 to 200 K for the Gd doping with x=0.3. The saturation moments at low temperature are significantly enhanced for the Gd doped …
Phase Formation And Magnetotransport Of Alkali Metal Doped Na0.75coo2 Thermoelectric Oxide, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou, H Yamauchi, M Karppinen
Phase Formation And Magnetotransport Of Alkali Metal Doped Na0.75coo2 Thermoelectric Oxide, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou, H Yamauchi, M Karppinen
Shi Xue Dou
Synthesis and characterization of bulk NaxCoO2 samples substituted by K and Rb is reported. Phase formation studies revealed a narrow stable region for Na-alkali metal-Co system. Whisker and platelike single crystalline structures have been found to form on the surface of the pellets in case of K doping. All samples were metallic and no characteristic anomaly in R-T curves was observed for Rb doped sample. Magnetoresistance measured has a pronounced positive response only for K-doped and pure NaxCoO2 phases, reaching 11% and 7% at 5 K temperature, respectively.
Attaching Molecular Hydrogen To Metal Cations: Perspectives From Gas-Phase Infrared Spectroscopy, Viktoras Dryza, Berwyck Poad, Evan Bieske
Attaching Molecular Hydrogen To Metal Cations: Perspectives From Gas-Phase Infrared Spectroscopy, Viktoras Dryza, Berwyck Poad, Evan Bieske
Berwyck L. J. Poad
In this perspective article we describe recent infrared spectroscopic investigations of mass-selected M+–H2 and M+–D2 complexes in the gas-phase, with targets that include Li+–H2, B+–H2, Na+–H2, Mg+–H2, Al+–H2, Cr+–D2, Mn+–H2, Zn+–D2 and Ag+–H2. Interactions between molecular hydrogen and metal cations play a key role in several contexts, including in the storage of molecular hydrogen in zeolites, metal–organic frameworks, and …
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Berwyck L. J. Poad
α-Carboxylate radical anions are potential reactive intermediates in the free radical oxidation of biological molecules (e.g., fatty acids, peptides and proteins). We have synthesised well-defined α-carboxylate radical anions in the gas phase by UV laser photolysis of halogenated precursors in an ion-trap mass spectrometer. Reactions of isolated acetate (CH2CO 2-) and 1-carboxylatobutyl (CH3CH 2CH2CHCO2-) radical anions with dioxygen yield carbonate (CO3-) radical anions and this chemistry is shown to be a hallmark of oxidation in simple and alkyl-substituted cross-conjugated species. Previous solution phase studies have shown that Cα-radicals in peptides, formed from free radical damage, combine with dioxygen to form …
Vapor Phase Polymerization Of Edot From Submicrometer Scale Oxidant Patterned By Dip-Pen Nanolithography, Cathal D. O'Connell, Michael J. Higgins, Hiroshi Nakashima, Simon E. Moulton, Gordon G. Wallace
Vapor Phase Polymerization Of Edot From Submicrometer Scale Oxidant Patterned By Dip-Pen Nanolithography, Cathal D. O'Connell, Michael J. Higgins, Hiroshi Nakashima, Simon E. Moulton, Gordon G. Wallace
Gordon Wallace
Some of the most exciting recent advances in conducting polymer synthesis have centered around the method of vapor phase polymerization (VPP) of thin films. However, it is not known whether the VPP process can proceed using significantly reduced volumes of oxidant and therefore be implemented as part of nanolithography approach. Here, we present a strategy for submicrometer scale patterning of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) via in situ VPP. Attolitre (10-18 L) volumes of oxidant "ink" are controllably deposited using dip-pen nanolithography (DPN). DPN patterning of the oxidant ink is facilitated by the incorporation of an amphiphilic block copolymer thickener, …
Frequency Selection In Absolute Phase Maps Recovery With Two Frequency Projection Fringes, Yi Ding, Jiangtao Xi, Yanguang Yu, Wengqing Cheng, Shu Wang, Joe F. Chicharo
Frequency Selection In Absolute Phase Maps Recovery With Two Frequency Projection Fringes, Yi Ding, Jiangtao Xi, Yanguang Yu, Wengqing Cheng, Shu Wang, Joe F. Chicharo
Dr Yanguang Yu
In a recent published work we proposed a technique to recover the absolute phase maps of two fringe patterns with different spatial frequencies. It is demonstrated that a number of selected frequency pairs can be used for the proposed approach, but the published work did not provide a guideline for frequency selection. In addition, the performance of the proposed technique in terms of its anti-noise capability is not addressed. In this paper, the rules for selecting the two frequencies are presented based on theoretical analysis of the proposed technique. Also, when the two frequencies are given, the anti-noise capability of …
A New Phase Unwrapping Algorithm Based On Three Wavelength Phase Shift Profilometry Method, Limei Song, Xiaoxiao Dong, Jiangtao Xi, Yanguang Yu, Chaokui Yang
A New Phase Unwrapping Algorithm Based On Three Wavelength Phase Shift Profilometry Method, Limei Song, Xiaoxiao Dong, Jiangtao Xi, Yanguang Yu, Chaokui Yang
Dr Yanguang Yu
Phase Shift Profilometry (PSP) method is widely used in 3D shape measurement. The advantage of the PSP method is that it is less sensitive to the surface reflectivity variations and the object can be measured point by point. But if only a single wavelength λ1 is used, the step height cannot be larger than λ1/4. In order to measure step height object, Gray Code (GC) and Multi-Wavelength Phase Shift Profilometry (MWPSP) method are used. But the GC method cannot solve the problem of the objects with a variety of colors under different illumination. The shortcoming of MWPSP …
Fast Quality-Guided Phase Unwrapping Algorithm For 3d Profilometry Based On Object Image Edge Detection, Ke Chen, Jiangtao Xi, Yanguang Yu
Fast Quality-Guided Phase Unwrapping Algorithm For 3d Profilometry Based On Object Image Edge Detection, Ke Chen, Jiangtao Xi, Yanguang Yu
Dr Yanguang Yu
A main challenge associated with 3-dimentional fringe pattern profilometry (3D-FPP) systems is the unwrapping of phase maps resulted from complex object surface shapes with both robustness and speed guaranteed. In this paper we propose a new quality-guided phase unwrapping algorithm. In contrast to the conventional quality-guided methods, we classify pixels on wrapped phase map into two types by detecting edge pixels on object image: high quality (HQ) pixels corresponding to smooth phase changes and low quality (LQ) ones to rough phase changes. In order to improve the computational efficiency, these two types of pixels are unwrapped by means of different …
Enhanced Molecular Chaperone Activity Of The Small Heat-Shock Protein Alphab-Cystallin Following Covalent Immobilization Onto A Solid-Phase Support, V Bellotti, Heath Ecroyd, J Carver, H J Griesser, B Thierry, J G Shapter, S S Griesser, S Giorgetti, M R Nussio, J A Gerrard, J Garvey
Enhanced Molecular Chaperone Activity Of The Small Heat-Shock Protein Alphab-Cystallin Following Covalent Immobilization Onto A Solid-Phase Support, V Bellotti, Heath Ecroyd, J Carver, H J Griesser, B Thierry, J G Shapter, S S Griesser, S Giorgetti, M R Nussio, J A Gerrard, J Garvey
Heath Ecroyd
The well-characterized small heat-shock protein, alphaB-crystallin, acts as a molecular chaperone by interacting with unfolding proteins to prevent their aggregation and precipitation. Structural perturbation (e.g., partial unfolding) enhances the in vitro chaperone activity of alphaB-crystallin. Proteins often undergo structural perturbations at the surface of a synthetic material, which may alter their biological activity. This study investigated the activity of alphaB-crystallin when covalently bound to a support surface; alphaB-crystallin was immobilized onto a range of solid material surfaces, and its characteristics and chaperone activity were assessed. Immobilization was achieved via a plasma-deposited thin polymeric interlayer containing aldehyde surface groups and reductive …
Application Of Multi-Phase Experiments In Plant Pathology To Identify Genetic Resistance To Diaporthe Toxica In Lupinus Albus, R. B. Cowley, G. J. Ash, J. D. I. Harper, Alison Smith, Brian Cullis, D. J. Luckett
Application Of Multi-Phase Experiments In Plant Pathology To Identify Genetic Resistance To Diaporthe Toxica In Lupinus Albus, R. B. Cowley, G. J. Ash, J. D. I. Harper, Alison Smith, Brian Cullis, D. J. Luckett
Dr Alison Smith
Phenotyping assays in plant pathology using detached plant parts are multi-phase experimental processes. Such assays involve growing plants in field or controlled-environment trials (Phase 1) and then subjecting a sample removed from each plant to disease assessment, usually under laboratory conditions (Phase 2). Each phase may be subject to nongenetic sources of variation. To be able to separate these sources of variation in both phases from genetic sources of variation requires a multi-phase experiment with an appropriate experimental design and statistical analysis. To achieve this, a separate randomization is required for each phase, with additional replication in Phase 2. In …