Recent publications in Physical Sciences

Lei, Peng, Zhou, Ying, Zhu, Ruiqi, Liu, Yang, Dong, Chuan, and Shuang, Shaomin (2020) Novel strategy of electrochemical analysis of DNA bases with enhanced performance based on copper−nickel nanosphere decorated N,B−doped reduced graphene oxide. Biosensors and Bioelectronics, 147. 111735.
Design of suitable nanocomposites with tailored structures was significant in the fabrication of effective and reliable electrochemical sensors. Herein, the copper−nickel@nitrogen, boron−doped reduced graphene oxide (Cu–Ni@N,B−rGO) was successfully synthesized, which exhibited superior electrocatalytic performance towards guanine (G) and adenine (A) oxidation. The Cu–Ni NPs were sequentially decorated on N,B−rGO substrate via an environmentally friendly reduction strategy, which utilized glucose as reducer and stabilizing agent. The nanocomposites with large specific surface area, remarkable conductivity and high catalytic activity showed prominent synergistic effect owning to the uniform dispersion of Cu–Ni NPs on the surface of N,B−rGO. When applied to analysis of G and A using DPV, the wide linear ranges of 1.0–160.0 μM and 1.0–120.0 μM with the determination limits of 0.118 μM and 0.134 μM were obtained, respectively. The sensor was successfully applied to the detection of G and A in calf−thymus DNA with G/A ratio of 0.80. The facile preparation process and attractive sensing properties of the Cu–Ni@N,B−rGO nanocomposites made it a promising candidate for the development of advanced electrochemical sensor.

Brice, Sara M., Phillips, Elissa J., Millett, Emma L., Hunter, Adam, and Philippa, Bronson (2019) Comparing inertial measurement units and marker-based biomechanical models during dynamic rotation of the torso. European Journal of Sport Science. (In Press)
Inertial measurement units (IMUs) enable human movements to be captured in the field and are being used increasingly in high performance sport. One key metric that can be derived from IMUs are relative angles of body segments which are important for monitoring form in many sports. The purpose of this study was to a) examine the validity of relative angles derived from IMUs placed on the torso and pelvis; and b) determine optimal positioning for torso mounted sensors such that the IMU relative angles match closely with gold standard torso-pelvis and thorax-pelvis relative angle data derived from an optoelectronic camera system. Seventeen adult participants undertook a variety of motion tasks. Four IMUs were positioned on the torso and one was positioned on the pelvis between the posterior superior iliac spines. Reflective markers were positioned around each IMU and over torso and pelvis landmarks. Results showed that the IMUs are valid with the root mean square errors expressed as a percentage of the angle range (RMSE%) ranging between 1% and 7%. Comparison between the IMU relative angles and the torso-pelvis and thorax-pelvis relative angles showed there were moderate to large differences with RMSE% values ranging between 4% and 57%. IMUs are highly accurate at measuring orientation data; however, further work is needed to optimize positioning and modelling approaches so IMU relative angles align more closely with relative angles derived using traditional motion capture methods.

Guo, Zhifang, Luu, Jenny, Blair, Victoria, Deacon, Glen B., and Junk, Peter C. (2019) Replacing mercury: syntheses of lanthanoid pyrazolates from free lanthanoid metals, pentafluorophenylsilver, and pyrazoles, aided by a facile synthesis of polyfluoroarylsilver compounds. European Journal of Inorganic Chemistry, 2019 (7). pp. 1018-1029.
The polyfluorophenylsilver complexes [Ag-2(C6F4Br-4)(2)(py)(3)] (py = pyridine) (1) and [{Ag2R2(py)(2)}(n)] [R = C6F5 (2); C6F4Br-3 (3); C6F4H-4 (4)] were prepared in reasonable yields by reactions of silver(I) oxide with the appropriate polyfluorobenzenes in pyridine. This simple and convenient synthesis is selective and does not lead to debromination of C6HF4Br-(3 or 4). Complex 1 is dinuclear with AgR2 and Ag(py)(3) units linked by a bridging polyfluoroaryl group and Ag center dot center dot center dot Ag interactions, whereas 2-4 are polymeric with alternating AgR2 and Ag(py)(2) units similarly linked. The trivalent lanthanoid pyrazolates, [Ln(Ph(2)pz)(3)(py)(2)]center dot 2thf (Ph(2)pz = 3,5-diphenylpyrazolate; Ln = Yb, 5, Er, 6, Dy, 7, Lu, 8; thf = tetrahydrofuran), [Ho(Ph(2)pz)(3)(py)(thf)] (9), [Ln(Ph(2)pz)(3)(py)(dme)]center dot solv (Ln = Tb, solv = 1.75PhMe, 10, Gd, solv = 1.5dme, 11; dme = 1,2-dimethoxyethane; PhMe = toluene), [Ln(Ph(2)pz)(3)(thf)(3)] (Ln = La, 12, Ce, 13, Nd, 14), [Ln(tBu(2)pz)(3)(py)(2)] (tBu(2)pz = 3,5-di-tert-butylpyrazolate; Ln = Yb, 15, Tm, 16, Ho, 17, Dy, 18), [Yb(Phtpz)(3)(py)(2)]center dot PhMe (19) (Phtpz = 3-Phenyl-5-(2 '-thienyl)pyrazolate) and [Nd(ttfpz)(3)(dme)(2)] (20) (ttfpz = 3-(2 '-thienyl)-5-(trifluoromethyl)pyrazolate) have been prepared by redox transmetallation/protolysis (RTP) reactions employing lanthanoid metals, pentafluorophenylsilver and the corresponding pyrazoles (pzH) in donor solvents. This is a new synthetic route in which AgC6F5 replaces the more commonly used Hg(C6F5)(2) or HgPh2. Yields are good to excellent if long crystallization times are used but the heavier Ln metals require activation with iodine to induce reaction. The monomeric structures exhibit eta(2)-bound pyrazolate ligands with eight-coordinate metal atoms for complexes 5-9 and 15-19, nine-coordinate metal atoms for complexes 10-14, and ten-coordinate metal atoms for complex 20.

Hughes, Terry P., Kerry, James T., Connolly, Sean R., Baird, Andrew H., Eakin, C. Mark, Heron, Scott F., Hoey, Andrew S., Hoogenboom, Mia O., Jacobson, Mizue, Liu, Gang, Pratchett, Morgan S., Skirving, William, and Torda, Gergely (2019) Ecological memory modifies the cumulative impact of recurrent climate extremes. Nature Climate Change, 9 (1). pp. 40-44.
Climate change is radically altering the frequency, intensity and spatial scale of severe weather events, such as heat-waves, droughts, floods and fires(1). As the time interval shrinks between recurrent shocks(2-5), the responses of ecosystems to each new disturbance are increasingly likely to be contingent on the history of other recent extreme events. Ecological memory-defined as the ability of the past to influence the present trajectory of ecosystems(6,7)-is also critically important for understanding how species assemblages are responding to rapid changes in disturbance regimes due to anthropogenic climate change(2,3,6-8). Here, we show the emergence of ecological memory during unprecedented back-to-back mass bleaching of corals along the 2,300 km length of the Great Barrier Reef in 2016, and again in 2017, whereby the impacts of the second severe heatwave, and its geographic footprint, were contingent on the first. Our results underscore the need to understand the strengthening interactions among sequences of climate-driven events, and highlight the accelerating and cumulative impacts of novel disturbance regimes on vulnerable ecosystems.

Lawn, Julian A., and Kosov, Daniel S. (2019) Coupled elastic membranes model for quantum heat transport in semiconductor nanowires. European Physical Journal B: Condensed Matter and Complex Systems, 92 (2). 43.
Presented here is a nanowire model, consisting of coupled elastic membranes with the purpose of investigating thermal transport in quasi-one-dimensional quantum systems. The vibrations of each elastic membrane are quantized and the flow of the vibrational energy between adjacent membranes is allowed. The ends of the nanowire are attached to thermal baths held at different temperatures. We derived quantum master equation for energy flow across the nanowire and obtained thermal currents and other key observables. We study the effects of a disordered boundary on the thermal current by randomizing the membrane radii. We evaluate the model as a nanowire analogue as well as study the effects of a disordered boundary on thermal conductivity. The calculations show that the membrane lattice model demonstrates diameter phonon confinement and a severe reduction in thermal conductivity due to surface roughness which is characteristic of semiconductor nanowires. The surface roughness also produces a length dependence of the thermal conductivity of the form κ = αLβ, with β dependent on disorder characteristics, in the otherwise ballistic regime. Finally, the parameters of the model are fitted to available experimental data for silicon nanowires and the results of the calculations are assessed against the experimental data.

Kershaw, Vincent F., and Kosov, Daniel S. (2019) Non-equilibrium Green's function theory for non-adiabatic effects in quantum transport: inclusion of electron-electron interactions. Journal of Chemical Physics, 150. 074101.
Non-equilibrium Green's function theory for non-adiabatic effects in quantum transport [Kershaw and Kosov, J. Chem. Phys. 147, 224109 (2017) and J. Chem. Phys. 149, 044121 (2018)] is extended to the case of interacting electrons. We consider a general problem of quantum transport of interacting electrons through a central region with dynamically changing geometry. The approach is based on the separation of time scales in the non-equilibrium Green's functions and the use of the Wigner transformation to solve the Kadanoff-Baym equations. The Green's functions and correlation self-energy are non-adiabatically expanded up to the second order central time derivatives. We produce expressions for Green's functions with non-adiabatic corrections and a modified formula for electric current; both depend not only on instantaneous molecular junction geometry but also on nuclear velocities and accelerations. The theory is illustrated by the study of electron transport through a model single-resonant level molecular junction with local electron-electron repulsion and a dynamically changing geometry.

Harvell, C. D., Montecino-Latorre, D., Caldwell, J. M., Burt, J. M., Bosley, K., Keller, A., Heron, S. F., Salomon, A. K., Lee, L., Pontier, O., Pattengill-Semmens, C., and Gaydos, J. K. (2019) Disease epidemic and a marine heat wave are associated with the continental-scale collapse of a pivotal predator (Pycnopodia helianthoides). Science Advances, 5. eaau7042.
Multihost infectious disease outbreaks have endangered wildlife, causing extinction of frogs and endemic birds, and widespread declines of bats, corals, and abalone. Since 2013, a sea star wasting disease has affected > 20 sea star species from Mexico to Alaska. The common, predatory sunflower star (Pycnopodia helianthoides), shown to be highly susceptible to sea star wasting disease, has been extirpated across most of its range. Diver surveys conducted in shallow nearshore waters (n = 10,956; 2006-2017) from California to Alaska and deep offshore (55 to 1280 m) trawl surveys from California to Washington (n = 8968; 2004-2016) reveal 80 to 100% declines across a similar to 3000-km range. Furthermore, timing of peak declines in nearshore waters coincided with anomalously warm sea surface temperatures. The rapid, widespread decline of this pivotal subtidal predator threatens its persistence and may have large ecosystem-level consequences.

Werner, Daniel, Deacon, Glen B., and Junk, Peter C. (2019) Trapping CS₂²⁻ and S₃²⁻ between two ytterbium formamidinates. Inorganic Chemistry, 58 (3). pp. 1912-1918.
Treatment of [YbII(DippForm)2(thf)n] (n = 2 (1aYb), n = 1 (1bYb); DippForm = N,N′-bis(2,6-diisopropylphenyl)formamidinate), with either excess CS2 or S8 gives [YbIII2(DippForm)4(CS2)] (3) and [YbIII2(DippForm)4(S2)0.5/(S3)0.5] (4) respectively. 3 is a new addition to an exclusive class of compounds containing the CS22− dianion, and 4 is the first crystallographically characterized example of a rare-earth trisulfide complex.

de Bruin-Dickason, Caspar N., Deacon, Glen B., Jones, Cameron, Junk, Peter C., and Wiecko, Michal (2019) Functionalised alkaline earth iodides from Grignard synthons "PhAeI(thf)ₙ" (Ae = Mg‐Ba). European Journal of Inorganic Chemistry, 2019 (7). pp. 1030-1038.
Derivatisation of Grignard synthons "PhAeI(thf)(n)" (Ae = Mg-Ba) prepared in situ from reactions of metal filings and iodobenzene provides a one-pot synthesis of heteroleptic N donor alkaline earth iodide complexes. Protolysis of "PhAeI(thf)(n)" with 3,5-diphenylpyrazole (Ph(2)pzH) yields pyrazolate complexes [Mg-2(mu-Ph(2)pz)(2)(I)(2)(thf)(3)] (1), [Ae(Ph(2)pz)(I)(thf)(4)] (Ae = Ca (2), Sr (3)), and [Ba-2(Ph(2)pz)(2)(mu-I)(2)(thf)(8)] (4). Addition of the Ae-Ph moiety to carbodiimide MesN=C=NMes (Mes = 2,4,6-(CH3)(3)C6H2) gave a series of benzamidinate iodide complexes [Ca-2{(MesN)(2)CPh}(2)(mu-I)(2)(thf)(4)] (6), [Sr{(MesN)(2)CPh}(I)(thf)(4)] (7), and [{Ba{(MesN)(2)CPh}(mu-I)(thf)(3)}(infinity)] (8). By contrast a symmetrical magnesium complex [Mg{(MesN)(2)CPh}(2)(thf)] (5) was obtained by Schlenk redistribution. These syntheses proceed without pre-activation of the metal for strontium and barium, and after activation with 2 mol-% iodine for calcium. The heavy alkaline earth metal complexes are the first examples of heteroleptic halide pyrazolate or amidinate complexes for strontium and barium. Complexes 1, 3, 4 and 6-8 were characterised crystallographically, revealing diverse structural chemistry of heteroleptic amidinate and pyrazolate iodide complexes across the alkaline earth series. A highlight is [Ba{(MesN)(2)CPh}(mu-I)(thf)(3)](infinity) (8) - an iodide bridged infinite 1-D polymer.

Sanderson, Stephen, Philippa, Bronson, Vamvounis, George, Burn, Paul L., and White, Ronald D. (2019) Understanding charge transport in Ir(ppy)₃:CBP OLED films. Journal of Chemical Physics, 150 (9). 094110.
Ir(ppy)₃:CBP blends have been widely studied as the emissive layer in organic light emitting diodes (OLEDs), yet crucial questions about charge transport within the layer remain unaddressed. Recent molecular dynamics simulations show that the Ir(ppy)₃ molecules are not isolated from each other, but at concentrations of as low as 5 wt. % can be part of connected pathways. Such connectivity raises the question of how the iridium(iii) complexes contribute to long-range charge transport in the blend. We implement a kinetic Monte Carlo transport model to probe the guest concentration dependence of charge mobility and show that distinct minima appear at approximately 10 wt. % Ir(ppy)₃ due to an increased number of trap states that can include interconnected complexes within the blend film. The depth of the minima is shown to be dependent on the electric field and to vary between electrons and holes due to their different trapping depths arising from the different ionization potentials and electron affinities of the guest and host molecules. Typical guest-host OLEDs use a guest concentration below 10 wt. % to avoid triplet-triplet annihilation, so these results suggest that optimal device performance is achieved when there is significant charge trapping on the iridium(iii) complex guest molecules and minimum interactions of the emissive chromophores that can lead to triplet-triplet annihilation.

Bloomfield, Keith J., Prentice, I. Colin, Cernusak, Lucas A., Eamus, Derek, Medlyn, Belinda E., Rumman, Rizwana, Wright, Ian J., Boer, Matthias M., Cale, Peter, Cleverly, James, Egerton, John J.G., Ellsworth, David S., Evans, Bradley J., Hayes, Lucy S., Hutchinson, Michael F., Liddell, Michael J., Macfarlane, Craig, Meyer, Wayne S., Togashi, Henrique F., Wardlaw, Tim, Zhu, Lingling, and Atkin, Owen K. (2019) The validity of optimal leaf traits modelled on environmental conditions. New Phytologist, 221 (3). pp. 1409-1423.
The ratio of leaf intercellular to ambient CO2 (χ) is modulated by stomatal conductance (gs). These quantities link carbon (C) assimilation with transpiration, and along with photosynthetic capacities (Vcmax and Jmax) are required to model terrestrial C uptake. We use optimization criteria based on the growth environment to generate predicted values of photosynthetic and water‐use efficiency traits and test these against a unique dataset. Leaf gas‐exchange parameters and carbon isotope discrimination were analysed in relation to local climate across a continental network of study sites. Sun‐exposed leaves of 50 species at seven sites were measured in contrasting seasons. Values of χ predicted from growth temperature and vapour pressure deficit were closely correlated to ratios derived from C isotope (δ13C) measurements. Correlations were stronger in the growing season. Predicted values of photosynthetic traits, including carboxylation capacity (Vcmax), derived from δ13C, growth temperature and solar radiation, showed meaningful agreement with inferred values derived from gas‐exchange measurements. Between‐site differences in water‐use efficiency were, however, only weakly linked to the plant's growth environment and did not show seasonal variation. These results support the general hypothesis that many key parameters required by Earth system models are adaptive and predictable from plants' growth environments.

Mcleod, Elizabeth, Anthony, Kenneth R. N., Mumby, Peter J., Maynard, Jeffrey, Beeden, Roger, Graham, Nicholas A. J., Heron, Scott F., Hoegh-Guldberg, Ove, Jupiter, Stacy, MacGowan, Petra, Mangubhai, Sangeeta, Marshall, Nadine, Marshall, Paul A., McClanahan, Tim R., Mcleod, Karen, Nyström, Magnus, Obura, David, Parker, Britt, Possingham, Hugh P., Salm, Rodney V., and Tamelander, Jerker (2019) The future of resilience-based management in coral reef ecosystems. Journal of Environmental Management, 233. pp. 291-301.
Resilience underpins the sustainability of both ecological and social systems. Extensive loss of reef corals following recent mass bleaching events have challenged the notion that support of system resilience is a viable reef management strategy. While resilience-based management (RBM) cannot prevent the damaging effects of major disturbances, such as mass bleaching events, it can support natural processes that promote resistance and recovery. Here, we review the potential of RBM to help sustain coral reefs in the 21st century. We explore the scope for supporting resilience through existing management approaches and emerging technologies and discuss their opportunities and limitations in a changing climate. We argue that for RBM to be effective in a changing world, reef management strategies need to involve both existing and new interventions that together reduce stress, support the fitness of populations and species, and help people and economies to adapt to a highly altered ecosystem.

Rudge, Samuel L., and Kosov, Daniel S. (2019) Nonrenewal statistics in quantum transport from the perspective of first-passage and waiting time distributions. Physical Review B, 99 (11). 115426.
The waiting time distribution has, in recent years, proven to be a useful statistical tool for characterizing transport in nanoscale quantum transport. In particular, as opposed to moments of the distribution of transferred charge, which have historically been calculated in the long-time limit, waiting times are able to detect nonrenewal behavior in mesoscopic systems. They have failed, however, to correctly incorporate backtunneling events. Recently, a method has been developed that can describe unidirectional and bidirectional transport on an equal footing: the distribution of first-passage times. Rather than the time between successive electron tunnelings, the first passage refers to the first time the number of extra electrons in the drain reaches +1. Here, we demonstrate the differences between first-passage time statistics and waiting time statistics in transport scenarios where the waiting time either cannot correctly reproduce the higher-order current cumulants or cannot be calculated at all. To this end, we examine electron transport through a molecule coupled to two macroscopic metal electrodes. We model the molecule with strong electron-electron and electron-phonon interactions in three regimes: (i) sequential tunneling and cotunneling for a finite bias voltage through the Anderson model, (ii) sequential tunneling with no temperature gradient and a bias voltage through the Holstein model, and (iii) sequential tunneling at zero bias voltage and a temperature gradient through the Holstein model. We show that for each transport scenario, backtunneling events play a significant role; consequently, the waiting time statistics do not correctly predict the renewal and nonrenewal behavior, whereas the first-passage time distribution does.

Zhu, Chengxi, Liu, Dong, Yuye, Li, Shen, Xiuli, Li, Libo, Liu, Yang, and You, Tianyan (2019) Ratiometric electrochemical, electrochemiluminescent and photoelectrochemical strategies for environmental contaminant detection. Current Opinion in Electrochemistry, 17. pp. 47-55.
Global environmental pollution issue has boosted the development of novel analytical techniques with high efficiency and accuracy for detection of hazardous contaminants. Strategies based on electrochemical, electrochemiluminescent, or photoelectrochemical analysis are among the promising detection approaches to provide rapid and sensitive analysis. Currently, combining ratiometric assay with such strategies can further promote their sensing reliability and reproducibility in complex conditions. This review highlights recent advances of ratiometric electrochemical, electrochemiluminescent, and photoelectrochemical sensors in the past 2 years. Their signal generation strategies and analysis applications, particularly for the environmental contaminant detection, are discussed in detail, and a future prospect in this area from us is also provided.

Wang, E., Attard, S., McGlinchey, M., Xiang, W., Philippa, B., Linton, A.L., and Everingham, Y. (2019) Smarter irrigation scheduling in the sugarcane farming system using the Internet of Things9. In: Proceedings of the 41st Annual Conference of the Australian Society of Sugar Cane Technologists (41) pp. 164-170. From: ASSCT 2019: 41st Annual Conference of the Australian Society of Sugar Cane Technologists, 30 April - 3 May 2019, Toowoomba, QLD, Australia.
Better irrigation practices can lead to improved yields through less water stress and reduced water usage to deliver economic benefits for farmers. More and more sugarcane growers are transitioning to automated irrigation in the Burdekin and other regions. Automated irrigation systems can save farmers a significant amount of time by remotely turning on and off pumps and valves. However, the system could be improved if it could be integrated with tools that factor in the weather, crop growing conditions, water deficit, and crop stress, to improve irrigation use efficiency. IrrigWeb is a decision-support tool that is turned to as a solution to this problem. IrrigWeb uses CANEGRO to help farmers decide when to irrigate and how much to apply. Farmers can then use this information to plan their irrigation management. However, managing irrigation is a considerable time investment for Burdekin farmers. A tool is needed to integrate the auto-irrigation system (e.g., WiSA) and IrrigWeb to provide a smarter irrigation solution. An uplink program (WiSA to IrrigWeb) has been successfully developed and implemented as part of a pilot study. It saves farmers a significant amount of time by uploading irrigation and rainfall data automatically instead of the farmer having to input them manually. This paper focuses on developing a smarter irrigation-scheduling tool that connects IrrigWeb to WiSA. A downlink program was developed to download, calculate and apply irrigation schedules automatically. In this process, sugarcane irrigators will spend less time manually setting up irrigation schedules as it will happen automatically. The simulation results demonstrated that the downlink program could improve the scheduling by incorporating practical limitations, such as pumping capacity or pumping time constraints, that are found on the farm.

Cocks, Daniel, Whittingham, Ian, and Peach, Gillian (2019) Ultracold homonuclear and heteronuclear collisions in metastable helium. Physical Review A (Atomic, Molecular and Optical Physics), 99 (6). 062712.
Scattering and ionizing cross sections and rates are calculated for ultracold collisions between metastable helium atoms using a fully quantum-mechanical close-coupled formalism. Homonuclear collisions of the bosonic ${}^{4}$He$^{*} +{}^{4}$He$^{*}$ and fermionic ${}^{3}$He$^{*} + {}^{3}$He$^{*}$ systems, and heteronuclear collisions of the mixed ${}^{3}$He$^{*} +{}^{4}$He$^{*}$ system, are investigated over a temperature range 1~$\mu$K to 1~K. Carefully constructed Born-Oppenheimer molecular potentials are used to describe the electrostatic interaction between the colliding atoms, and complex optical potentials used to represent loss through ionization from the ${}^{1,3}\Sigma $ states. Magnetic spin-dipole mediated transitions from the ${}^{5}\Sigma $ state are included and results reported for spin-polarized and unpolarized systems. Comparisons are made with experimental results, previous semi-classical models, and a perturbed single channel model.

Lei, Peng, Zhou, Ying, Zhu, Ruiqi, Liu, Yang, Dong, Chuan, and Shuang, Shaomin (2019) Facile synthesis of iron phthalocyanine functionalized N,B–doped reduced graphene oxide nanocomposites and sensitive electrochemical detection for glutathione. Sensors and Actuators B: Chemical, 297. 126756.
Iron phthalocyanine (FePc) functionalized nitrogen, boron–doped reduced graphene oxide (N,B–rGO) nanocomposite (FePc/N,B–rGO) was facilely fabricated for the first time as a electrochemical platform for sensitive detection of glutathione (GSH). FePc was immobilized on N,B–rGO substrate through π–π interaction, and N,B–rGO provided FePc with a large specific surface area to improve electron transfer and maintain its electrocatalytic activity. Cyclic voltammetric measurements showed that FePc and N,B–rGO triggered the synergistic effect and exhibited a satisfactory electrocatalytic activity. By integration of FePc and N,B–rGO, the FePc/N,B–rGO/GCE sensor displayed a wide linear dynamic range from 5.0 × 10–8 M to 1.6 × 10–3 M with a low detection limit of 7.1 × 10–9 M. Besides, the electrochemical sensor presented satisfiable reproducibility, excellent anti–interference performance and long–term stability. The method was further expanded to determinate GSH in human serum sample with the recoveries between 95.0–109.0%.

Pratchett, Morgan, Bridge, Thomas, Brodie, Jon, Cameron, Darren, Day, Jonathan, Emslie, Mike, Grech, Alana, Hamann, Mark, Heron, Scott, Hoey, Andrew, Hoogenboom, Mia, Lough, Janice, Morrison, Tiffany, Osborne, Kate, Read, Mark, Schauble, Chloe, Smithers, Scott, Sweatman, Hugh, and Waterhouse, Jane (2019) Australia's Great Barrier Reef. In: Sheppard, Charles, (ed.) World Seas: an environmental evaluation. Elsevier, London, UK, pp. 333-362.
Australia’s Great Barrier Reef (the GBR) is an iconic natural ecosystem, globally renowned for its majesty and grandeur. The GBR encompasses a vast array of unique and important marine and terrestrial habitats, from deepwater reefs to archetypal barrier reefs, as well as vast seagrass and algal meadows, intertidal mud flats, sand cays, and continental islands. The variety of environments and habitats encompassed within the GBR gives rise to extraordinary biodiversity. The GBR is also unusual compared with most reef systems around the world because the islands and adjacent coastal areas are sparsely populated. Moreover, Australia is a developed economy and does not generally rely heavily on subsistence or artisanal extraction of reef resources. That said, the GBR is being increasingly threatened by anthropogenic activities, such as land clearing and agricultural runoff, coastal development, pollution, and above all, increasing global carbon emissions that are rapidly changing environmental conditions. Sustained and ongoing global climate change has culminated in unprecedented and recurrent mass coral bleaching in recent years, which now represents the foremost threat to the integrity, functioning, and biodiversity of coral reef environments. Significant investment and effort is committed to conserving the GBR, both to maintain the ecological function and human benefits derived from the various natural systems, but the effectiveness and longer-term benefit of established and renewed management actions are conditional on immediate and effective action to reduce global carbon emissions.

Reimers, Jeffrey R., Wang, Yin, and Kosov, Daniel S. (2019) Decomposition of ferrocene on Pt(111) and its effect on molecular electronic junctions. Journal of Physical Chemistry Part C, 123. pp. 15569-15574.
From dilute vapor, ferrocene encountering Pt(111) decomposes, producing bound cyclopentadienyl rings, in contrast to its legendary stability in solution electrochemistry. We propose that decomposition occurs through initial chemisorption, making a Pt−C bond to a ferrocenium hydride, followed by step-edge catalyzed decomposition leading to migration of the Fe atom inside the Pt bulk. These conclusions are based on results from density functional theory (DFT) calculations. When Pt(111) approaches ferrocene tethered to a self-assembled monolayer, only the first, spontaneous but mechanically reversible chemisorption is predicted. Nonequilibrium Green's function calculations utilizing DFT predict that chemisorption increases molecular junction conductivities by a factor of 2−5. This could contribute to the extremely high conductivities observed in junctions supporting rectification up to unprecedented high-frequency cutoffs of ∼520 GHz, though squashed junctions at half monolayer coverage are predicted to conduct 104 times better.

Glasson, Christopher R.K., Donnet, Luke, Angell, Alex, Vucko, Matthew J., Lorbeer, Andrew J., Vamvounis, George, de Nys, Rocky, and Magnusson, Marie (2019) Multiple response optimisation of the aqueous extraction of high quality ulvan from Ulva ohnoi. Bioresource Technology Reports, 7. 100262.
Response surface methodology was used to determine the effects of the solvent pH, the temperature of extraction, and the duration of extraction on the yield, purity, molecular weight, viscosity, and total metal content of ulvan extracted from U. ohnoi. Quadratic models identified the optimised responses for yield (72.6%) purity (68.2% w/w), molecular weight (92.9 kDa), viscosity (491.1 s), and total metal content (~0 mg/kg). These responses occurred between a solvent pH of 2.2–4.0, an extraction temperature of 61.3–90.0 °C, and an extraction duration of 55.0–90.0 min. The overall desirability of the ulvan product was determined using a Derringer's desirability function, which identified a solvent pH of 2.92, an extraction temperature of 90 °C, and an extraction duration of 90 min. These extraction conditions minimise the requirement for downstream purification and are suitable for upscaling the extraction of a high quality ulvan product.

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