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Browsing by Author "Hanley, TL"

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Analysis of monoPEGylated human galectin-2 by small-angle x-ray and neutron scattering: concentration dependence of PEG conformation in the conjugate
(American Chemical Society, 2010-12-01) He, LH; Wang, H; Garamus, VM; Hanley, TL; Lensch, M; Gabius, HJ; Fee, CJ; Middelberg, APJ
Protein conjugation with polyethylene glycol (PEG) is a valuable means for improving stability, solubility, and bioavailability of pharmaceutical proteins. Using human galectin-2 (hGal-2) and 5 kDa PEG as a model system we first produced a PEG-hGal-2 conjugate exclusively at the Cys75 residue, resulting in two monosubstituted subunits per hGal-2 homodimer. Small angle X-ray and neutron scattering (SAXS and SANS) were combined to provide complementary structural information about the PEG-hGal-2 conjugate, wherein signal generation in SAXS depends mainly on the protein while SANS data presents signals from both the protein and PEG moieties. SAXS data gave a constant radius of gyration (Rg = 21.5 Å) for the conjugate at different concentrations and provided no evidence for an alteration of homodimeric structure or hGal-2 ellipsoidal shape upon PEGylation. In contrast, SANS data revealed a concentration dependence of Rg for the conjugate, with the value decreasing from 31.5 Å at 2 mg/mL to 26 Å at 14 mg/mL (based on hGal-2 concentration). Scattering data have been successfully described by the model of the ellipsoidal homogeneous core (hGal-2) attached with polymer chains (PEG) at the surface. Evidently, the PEG conformation of the conjugate strongly depends on conjugate concentration and PEG’s radius of gyration decreases from 24.5 to 15 Å. An excluded volume effect, arising from steric clashes between PEG molecules at high concentration, was quantified by estimating the second virial coefficient, A2, of PEGylated hGal-2 from the SANS data. A positive value of A2 (6.0 ± 0.4 × 10−4 cm3 mol g−2) indicates repulsive interactions between molecules, which are expected to protect the PEGylated protein against aggregation. © 2010 American Chemical Society
Ceramic conversion and densification of zirconium phosphonate sorbent materials
(Elsevier, 2018-04-01) Veliscek-Carolan, J; Thorogood, GJ; Gregg, DJ; Tansu, M; Hanley, TL
The simple conversion of zirconium phosphonate sorbent materials, with known affinity for lanthanide elements, to durable ceramic waste forms via thermal treatment has been demonstrated. The use of zirconium phosphonate enables both removal of targeted elements from spent nuclear fuel and immobilisation into leach resistant solid products to be achieved using a single material. Thermal conversion was performed on the zirconium phosphonate both before and after loading with europium, which acted as a surrogate for the chemically similar minor actinides. Without europium loaded, the zirconium phosphonate sorbent formed predominantly KZr2(PO4)3 upon heating, independent of the processing conditions used. A maximum relative density of 87% was achieved with cold isostatic pressing (200 MPa) and sintering at 1200 °C for 12 h. When the zirconium phosphonate sorbent was loaded with europium, the phase composition formed upon thermal treatment was more complex. Specifically, mixtures of ZrP2O7, Eu0.33Zr2(PO4)3, EuPO4 and Zr2O(PO4)2 were formed, with phase compositions depending on the temperatures and pressures used. The simplest phase composition for the europium loaded material was achieved via uniaxial pressing (120 MPa) and sintering at 1300 °C for 1 h, although the ceramic pellet produced under these conditions had a relative density of only 53%. The loaded europium deported primarily to a EuPO4 phase, which is known to be highly stable and leach resistant. As such, these zirconium phosphonate materials have potential utility for treatment of nuclear wastes. © 2019 Elsevier B.V.
Characterizing the photoinduced switching process of a nitrospiropyran self-assembled monolayer using in situ sum frequency generation spectroscopy
(American Chemical Society, 2012-10-02) Darwish, TA; Tong, YJ; James, M; Hanley, TL; Peng, QL; Ye, S
Sum frequency generation (SFG) vibrational spectroscopy is employed to investigate the reversible, photoinduced spiro -> merocyanine isomerization of a self-assembled monolayer, the result of attachment of nitrospiropyran to a gold surface using a dithiolane anchoring group. The attachment of these molecular "alligator clips" to spiropyran molecules provide an easily accessible method to self-assemble a robust monolayer of spiropyran on a gold surface, which allows photoswitching of the spiropyran units. Probing the symmetric and antisymmetric stretching modes of the nitro group allows the determination of the structural orientation of the charged moiety with respect to the surface normal as well as the isomerization rates under photoinduced switching conditions. The photoisomerization of the spiropyran SAM on the gold surface is much faster than the rates of switching spiropyrans in a solid crystalline form, and the rate of thermal relaxation of the opened to closed form in this study is found to be on the same time scale as the relaxation of spiropyran when present in solutions with polar solvents. © 2012, American Chemical Society.
CO2 triggering and controlling orthogonally multiresponsive photochromic systems
(American Chemical Society, 2010-08-11) Darwish, TA; Evans, RA; James, M; Malic, N; Triani, G; Hanley, TL
We report a new generic method of reversibly controlling the photochromism of spiropyrans. It was found that the photochromic effect of spiropyrans can be reversibly switched on and off by addition and removal of carbon dioxide (CO2) to spiropyran in alcohol solutions containing an amidine (i.e., DBU) that acts as a CO2 sensitizer. Spiropyrans are not photochromic in the presence of DBU but photochromic when CO2 is subsequently added to the solution. The CO2 is readily removed by inert gas bubbling, thus allowing facile activation and deactivation of the photochromic effect. Carbon dioxide, without the presence of the sensitizing amidine, had no effect on photochromism of the spiropyrans. Other photochromic dyes classes such as spirooxazines and chromenes are not affected by this CO2/DBU stimulus. As a result, orthogonal activation of mixtures of spirooxazines and spiropyrans was achieved to provide four color states (clear, yellow, green, and blue) by varying the combinations of the stimuli of UV, visible light, CO2, and CO2 depleted. This finding now permits the many applications using spiropyrans to be CO2 responsive. © 2010, American Chemical Society
Comparison of the so-called CGR and NCR cathodes in commercial lithium-ion batteries using in situ neutron powder diffraction
(Cambridge University Press, 2014-12-18) Alam, M; Hanley, TL; Pang, WK; Peterson, VK; Sharma, N
The evolution of the 003 reflection of the layered Li(Ni,Co,Mn)O2 (CGR) and Li(Ni,Co,Al)O2 (NCR) cathodes in commercial 18650 lithium-ion batteries during charge/discharge were determined using in situ neutron powder diffraction. The 003 reflection is chosen as it is the stacking axis of the layered structure and shows the largest change during charge/discharge. The comparison between these two cathodes shows that the NCR cathode exhibits an unusual contraction near the charged state and during the potentiostatic step, where the potentiostatic step is recommended by the manufacturer. This feature is not shown to the same degree by the CGR cathode. The behavior is likely related to the compositions of these cathodes, the amount of Li/Ni site mixing and the presence of Al or Mn. © 2014 International Centre for Diffraction Data. Published by Cambridge University Press
Controlling the nanostructure of gold nanorod-lyotropic liquid-crystalline hybrid materials using near-infrared laser irradiation
(American Chemical Society, 2012-10-09) Fong, WK; Hanley, TL; Thierry, B; Kirby, N; Waddington, LJ; Boyd, BJ
Lipid-based liquid-crystalline matrixes provide a unique prospect for stimuli-responsive nanomaterials, attributed to the ability to effect self-assembly of the lipids at the molecular level. Differences in liquid crystal nanostructure have previously been shown to change drug diffusion and hence release, with research progressing toward the use of in situ changes to nanostructure to control drug release. Toward this goal, we have previously communicated the ability to switch between nonlamellar structures using gold nanorod (GNR)-phytantriol-based liquid-crystalline hybrid nanomaterials as near-infrared light responsive systems (Fong et al. Langmuir 2010, 26, 6136-6139). In this study, the effect of laser activation on matrix nanostructure with changes in a number of system variables including lipid composition, GNR aspect ratio, GNR concentration, and laser pulse time were investigated. The nanostructure of the matrix was followed using small-angle X-ray scattering, while both cryoFESEM and cryoTEM were used to visualize the effect of GNR incorporation into the liquid crystal nanostructure. The system response was found to be dependent on all variables, thus demonstrating the potential of these nanocomposite materials as reversible "on-demand" drug delivery applications. © 2012, American Chemical Society.
Cubosomes containing the adjuvants imiquimod and monophosphoryl lipid a stimulate robust cellular and humoral immune responses
(Elsevier, 2013-01-10) Rizwan, SB; McBurney, WT; Young, K; Hanley, TL; Boyd, BJ; Rades, T; Hook, S
New generation vaccines increasingly utilize highly purified peptides and proteins as the target antigen, however these are often poorly immunogenic. One of the most promising strategies for improving immunogenicity of such subunit vaccines is through incorporation into particulate carriers. Here we report the preparation, physicochemical characterization and in vivo immunological activity of cubosomes, a novel lipid-based nanostructured particulate carrier, modified to include the Toll-like receptor agonists monophosphoryl lipid A and imiquimod. The immunological activity of cubosome formulations was compared to that of liposome and alum formulations. Sustained release of the model antigen ovalbumin (Ova) was observed in vitro and in vivo from cubosomes. Cubosomes + adjuvants induced robust CD8(+) and CD4(+) T cell proliferation and interferon-gamma production, as well as the production of Ova-specific antibodies. Cubosomes+ adjuvants were more efficient at generating Ova-specific cellular responses and were equally as effective in generating humoral responses when compared to liposomes + adjuvants and alum. Overall, the results show that cubosomes have the potential to act as effective sustained release vaccine delivery systems. © 2013, Elsevier Ltd.
Cyclic voltammetric experiment - simulation comparisons of the complex mechanism associated with electrochemical reduction of Zr4+ in LiCl-KCl eutectic molten salt
(The Electrochemical Society, 2012-11-29) Fabian, CP; Luca, V; Le, TH; Bond, AM; Chamelot, P; Massot, L; Caravaca, C; Hanley, TL; Lumpkin, GR
Nuclear energy increasingly represents an important option for generating largely clean CO2-free electricity and zirconium is a fission product that is expected to be present in irradiated fuels. The present investigation addresses the electrochemical reduction of Zr4+ to Zro in LiCl - KCl eutectic molten salt in the temperature range 425–550°C using cyclic voltammetry (CV), square-wave voltammetry (SWV) and bulk electrolysis. Simulations of the CV data indicate that the initial reduction proceeds through surface confined steps: Zr4+* + 2e− ↔ Zr2+* and Zr2+* + 2e− ↔ Zr* processes (* adsorbed species) followed by a peak-shaped complex diffusion controlled step that consists of a combination of closely spaced processes associated with the reactions Zr4+ + 4e− → Zro and Zr4+ + 3e− → Zr+*. Zr+*, probably in the form of ZrCl* is then further reduced to Zro* at even more negative potentials. The simulations provide the first quantitative analysis of the thermodynamics and kinetics of the Zr4+ reduction in the LiCl-KCl eutectic. © 2012, The Electrochemical Society.
Dispersing single-walled carbon nanotubes in ionic liquids: a quantitative analysis
(Royal Society of Chemistry, 2013-08-15) Hameed, N; Church, JS; Salim, NV; Hanley, TL; Amini, A; Fox, BL
The efficiency of various ionic liquids, specifically the 1-butyl-3-methylimidazolium tetrafluoroborate, hexafluorophosphate, chloride and dicyanamide salts, in dispersing single walled carbon nanotubes has been examined. The SWCNTs were dispersed in the ILs at varying concentrations by grinding. All of the ILs were found to be effective dispersants for nanotubes and quantitative evidences including X-ray scattering, Raman spectroscopy and UV-visible spectroscopy unambiguously showed that BMIM[BF4] is the most efficient IL while BMIM[DCA] is the least effective IL. A quantitative analysis of the interactions between SWCNTs and ionic liquids by analyzing their scattering and spectral features is put forth.© 2013, The Royal Society of Chemistry.
Domain organization of the monomeric form of the Tom70 mitochondrial import receptor
(Elsevier, 2009-05-22) Mills, RD; Trewhella, J; Qiu, TW; Welte, T; Ryan, TM; Hanley, TL; Knott, RB; Lithgow, T; Mulhern, TD
Tom70 is a mitochondrial protein import receptor composed of 11 tetratricopeptide repeats (TPRs). The first three TPRs form an N-terminal domain that recruits heat shock protein family chaperones, while the eight C-terminal TPRs form a domain that receives, from the bound chaperone, mitochondrial precursor proteins destined for import. Analytical Ultracentrifugation and solution small-angle X-ray scattering (SAXS) analysis characterized Tom70 as an elongated monomer. A model for the Tom70 monomer was proposed based on the alternate interpretation of the domain pairings observed in the crystal structure of the Tom70 dimer and refined against the SAXS data. In this "open" model of the Tom70 monomer, the chaperone- and precursor-binding sites are exposed and lay side by side oil one face of the molecule. Fluorescence anisotropy measurements indicated that monomeric Tom70 can bind both chaperone and precursor peptides and that chaperone peptide binding does not alter the affinity of Tom70 for the precursor peptide. SAXS Was unable to detect any shape change in Tom70 upon chaperone binding. However, molecular modeling indicated that chaperone binding is incompatible with Tom70 dimer formation. It is proposed that the Tom70 monomer is the functional unit mediating initial chaperone docking and precursor recognition. © 2009, Elsevier Ltd.
The effect of a rapid heating rate, mechanical vibration and surfactant chemistry on the structure–property relationships of epoxy/clay nanocomposites
(Multidisciplinary Digital Publishing Institute (MDPI), 2013-08-20) Nuhiji, B; Attard, DJ; Thorogood, GJ; Hanley, TL; Magniez, K; Bungur, J; Fox, B
The role of processing conditions and intercalant chemistry in montmorillonite clays on the dispersion, morphology and mechanical properties of two epoxy/clay nanocomposite systems was investigated in this paper. This work highlights the importance of employing complementary techniques (X-ray diffraction, small angle X-ray scattering, optical microscopy and transmission electron microscopy) to correlate nanomorphology to macroscale properties. Materials were prepared using an out of autoclave manufacturing process equipped to generate rapid heating rates and mechanical vibration. The results suggested that the quaternary ammonium surfactant on C30B clay reacted with the epoxy during cure, while the primary ammonium surfactant (I.30E) catalysed the polymerisation reaction. These effects led to important differences in nanocomposite clay morphologies. The use of mechanical vibration at 4 Hz prior to matrix gelation was found to facilitate clay dispersion and to reduce the area fraction of I.30E clay agglomerates in addition to increasing flexural strength by over 40%. © 2013 by the Authors. This is an open access article distributed under the Creative Commons Attribution License.
The effect of alternate heating rates during cure on the structure-property relationships of epoxy/MMT clay nanocomposites
(Elsevier, 2011-10-24) Nuhiji, B; Attard, DJ; Thorogood, GJ; Hanley, TL; Magniez, K; Fox, B
This paper investigates the effect of both the mixing technique and heating rate during cure on the dispersion of montmorillonite (MMT) clay in an epoxy resin. The combination of sonication and using a 10 degrees C/min heating rate during cure was found to facilitate the dispersion of nanoclay in epoxy resin. These processing conditions provided a synergistic effect, making it possible for polymer chains to penetrate in-between clay galleries and detach platelets from their agglomerates. As the degree of dispersion was enhanced, the flexural modulus and strength properties were found to decrease by 15% and 40%, respectively. This is thought to be due to individual platelets fracturing in the nanocomposite. Complementary techniques including X-ray diffraction (XRD), small angle X-ray scattering (SAXS), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX). transmission electron microscopy (TEM) and optical microscopy were essential to fully characterise localised and spatial regions of the clay morphologies. (C) 2011 Elsevier Ltd.
Effective Am(III)/Eu(III) separations using 2,6-bis(1,2,4-triazin-3-yl)pyridine (BTP) functionalised titania particles and hierarchically porous beads
(Royal Society of Chemistry, 2015-06-12) Veliscek-Carolan, J; Jolliffe, KA; Hanley, TL
Hybrid materials which selectively extract Am(III) over Eu(III) from 0.01 M nitric acid solutions with fast kinetics and separation factors up to 160 have been synthesised. The materials consist of titania functionalised with a modified organic 2,6-bis(1,2,4-triazin-3-yl)pyridine (BTP) derivative. Both particles and hierarchically porous beads have been prepared and provide advantages over conventional solvent extraction separations. © 2015 The Royal Society of Chemistry
Effects of precursor solution aging and other parameters on synthesis of ordered mesoporous titania powders
(American Chemical Society, 2015-03-11) Veliscek-Carolan, J; Knott, RB; Hanley, TL
Evaporation-induced self-assembly (EISA) of ordered mesoporous titania powders using block copolymer templates Brij 58 and F127 has been studied as a function of the precursor solution composition and age as well as the evaporation conditions. Small-angle X-ray scattering was used to monitor the degree of order in the mesoporous structure of materials synthesized under these varying conditions. Also, for the first time, the time-dependent formation of Ti structures in precursor solutions and the effect of those structures on the creation of mesostructural order have been demonstrated. The interactions of the Ti precursor with Brij 58 and F127 were investigated and showed that the different templates caused formation of Ti oligomers of unique sizes and structures. Precursor solution composition and evaporation conditions were also shown to affect the order and stability of the mesoporous titania produced. Overall, this systematic study has provided fundamental insights into the synthesis conditions that maximize the degree of order and thermal stability of the final materials. These “optimal” conditions are highly dependent on the choice of template. As a result of this improved understanding, the synthesis of ordered mesoporous titania powders using the block copolymer F127 as a template has been achieved without the use of stabilizing agents for the first time. © 2015 American Chemical Society
Effects of selected process parameters on the morphology of poly(ethylene terephthalate) preforms and bottles
(Wiley-Blackwell, 2007-10-05) Hanley, TL; Sutton, D; Karatchevtseva, I; Cookson, DJ; Burford, RP; Knott, RB
Small-angle X-ray scattering (SAXS) studies and polarized optical microscopy were undertaken to explore possible morphological explanations for the poor mechanical strength in the petaloid bases of poly(ethylene terephthalate) bottles. With a standard commercial production line, one set of injection-molded preforms was over-packed by 1.1 wt % to investigate the effect on the molecular morphology with respect to a set of control samples. Both sets of preforms showed highly crystalline and oriented areas corresponding to the injection gate region. The main body of the control preform was amorphous, and although the overpacked preform was essentially amorphous, there was some evidence for weak crystallinity. The SAXS patterns of the bottle petaloid base blown from the corresponding preforms produced similar SAXS patterns for overpacked and control bottle bases, indicating that the commercial process is robust at least to this degree of overpacking. Optical microscopy showed detailed crystalline features around the gate region and thin crystalline layers sandwiched between a quenched skin layer in direct contact with the cold mold walls and the main flow of material into the mold. © 2007, Wiley-Blackwell.
Experimental validation of proton transverse relaxivity models for superparamagnetic nanoparticle MRI contrast agents.
(Institute of Physics, 2010-01-22) Carroll, MRJ; Woodward, RC; House, MJ; Teoh, WY; Amal, R; Hanley, TL; St Pierre, TG
Analytical models of proton transverse relaxation rate enhancement by magnetic nanoparticles were tested by making measurements on model experimental systems in a field of 1.4 T. Proton relaxivities were measured for five aqueous suspensions of iron oxide (maghemite) nanoparticles with nominal mean particle sizes of 6, 8, 10, 11, and 13 nm. Proton relaxivity increased with mean particle size ranging from 13 s(-1) mM Fe-1 for the 6 nm sample, up to 254 s(-1) mM Fe-1 for the 13 nm sample. A strong correlation between the measured and predicted values of the relaxivity was observed, with the predicted values being consistently higher than the measured values. The results indicate that the models give a reasonable agreement with experimental results and hence can be used as the basis for the design of new magnetic resonance imaging contrast and labelling agents. © 2010, Institute of Physics
External manipulation of nanostructure in photoresponsive lipid depot matrix to control and predict drug release in vivo
(Elsevier B.V., 2016-04-28) Fong, WK; Hanley, TL; Thierry, B; Hawley, A; Boyd, BJ; Landersdorfer, CB
On-demand drug delivery systems are highly promising to control the time-course of drug release and ultimately optimize drug concentration time profiles in patients. Lipid based lyotropic liquid crystalline mesophases have demonstrated exceptional responsiveness to external stimuli such as heat, pH and light. Our objective was to quantitatively characterize the time-course of light activated drug release from near infrared (NIR) activated photothermal systems using ex vivo and in vivo studies. Photoresponsive hybrid gold nanorod-liquid crystalline matrices were prepared and loaded into custom-made implants which were inserted into subcutaneous tissues in rats. Time resolved SAXS studies showed the abdomen to be the best site of implantation to achieve in vivo activation of the subcutaneous dose from by the NIR laser. External control of drug release was achieved via NIR laser light and plasma concentrations of the model drug were determined over time. Laser activation achieved a phase change of the photoresponsive formulations and thereby a considerable change in the rate of drug release. Population pharmacokinetic modeling of all results simultaneously revealed a two stage release process unique to these liquid crystalline matrices. The developed structural model was able to successfully describe also the results of our previous study in 2009 where a change in temperature was utilized to trigger subcutaneous drug release. Thus, modeling of the data proved to be a valuable analytical tool which provided a quantitative understanding of the time-course of drug release in vivo and will be essential in the development of these matrices as on-demand release systems. © 2016, Elsevier B.V.
Grazing incidence x-ray studies of ultra-thin lumogen films.
(Elsevier, 2007-12-15) Keough, SJ; Hanley, TL; Wedding, AB; Quinton, JS
Lumogen® Yellow S0790 films have been produced on silicon wafer substrates via physical vapour deposition (PVD) and spin-coating (SC) methods. These coatings were characterised with X-ray reflectometry (XRR) and grazing incidence X-ray diffraction (GIXD) techniques. The results show that ultra-thin (less than 12nm) PVD films coat amorphously, with crystallinity becoming increasingly apparent with increasing film thickness. In contrast, measurements of ultra-thin (less than 2nm) spin-coated films reveal a second, apparently stable crystalline structure. © 2007, Elsevier Ltd.
Hierarchically porous carbon–zirconium carbide spheres as potentially reusable transmutation targets
(Elsevier, 2015-08-01) Scales, N; Chen, J; Hanley, TL; Riley, DP; Lumpkin, GR; Luca, V
The preparation of hierarchically porous phase-pure carbon–zirconium carbide spheres with surface areas upwards of 70 m2/g and diameters in the 1–2 mm range has been achieved. The zirconium carbide beads were prepared through carbothermal reduction of polyacrylonitrile-zirconium composites prepared via three different routes including infiltration of a zirconium precursor into preformed polyacrylonitrile (PAN) beads and two one-pot co-precipitation methods. Depending on the route used to prepare the composites, relatively high surface area phase-pure zirconium carbides with the radial macroporous internal structure of the PAN template could be prepared. The adsorption of the elements U, Mo, Cs and Sr by the zirconium carbide beads was studied as a function of pH in the range 1–13 and target element concentrations of 0.025 mmol/L. The as-prepared hierarchical zirconium carbide beads demonstrated almost quantitative uptake of Mo below pH 4 with uptake decreasing to close to zero and above pH 10.5. On the other hand, U uptake was negligible below pH 4 and became quantitative in the range 4–12. Cesium was not extracted to any significant extent in the pH range studied and Sr only to a limited extent above pH 10. The engineered hierarchical porosities, neutron transparency, thermal stability and anticipated chemical stability of the present zirconium carbide spheres makes them promising candidates as reusable transmutation targets for Minor Actinide incineration. © 2015 Elsevier Inc.
High-temperature corrosion of helium ion-irradiated Ni-based alloy in fluoride molten salt
(Elsevier, 2015-02-01) Zhu, HL; Holmes, R; Hanley, TL; Davis, J; Short, KT; Edwards, L
A comparison of the effect of helium-ion-radiation damage on a Ni–Mo–Cr–Fe alloy exposed to high-temperature (750 °C) corrosion in eutectic LiF–NaF–KF molten salt has been made. Microstructural examination showed that both the corroded-only and irradiated and corroded samples exhibit the characteristics of intergranular corrosion. However, helium ion irradiation introduces defects such as helium bubbles and cavities into the microstructure, greatly increasing intragranular corrosion of the irradiated sample. The thickness of the remaining corrosion zone for the irradiated sample was much greater than that for the unirradiated sample. © 2014 Elsevier Ltd.

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