Chris Glover

(Pentamethylcyclopentadienato)rhodium Complexes for Delivery of the Curcumin Anticancer Drug

Publisher: Wiley

Date: 16-02-2017

DOI: 10.1002/EJIC.201601331

Abstract: [Rh III (*Cp)Cl(X,Y)] n + complexes {X, Y = Cl, PTA, n = 0 ( 2 ) X, Y = en, n = 1 ( 3 , Cl – salt 4 , PF 6 – salt) X, Y = acac, n = 0 ( 5 ) X, Y = cur, n = 0 ( 6 ), where *Cp = pentamethylcyclopentadienato, curH = curcumin PTA = 1,3,5‐triaza‐7‐phosphatricyclo[3.3.1.1]decane en = 1,2‐ethanediamine acac = acetylacetonato = 2,4‐pentanedionato(1–)} were synthesized from [Rh(*Cp)(µ‐Cl)Cl] 2 ( 1 ). While 2 – 5 were inactive against human epithelial A549 lung‐cancer cells in assays of cytotoxicity, and antimetastatic and proapoptotic behaviors, 6 had a cytotoxic activity similar to that of curH over 72 h, but at 24 h in real‐time cell migration assays, it was less active, showing slow release of curH. All complexes underwent ligand‐exchange reactions with biomolecules and cells within the timeframes of the assays (X‐ray absorption spectroscopy). Intracellular elemental distributions (X‐ray fluorescence microscopy) showed that 6 effectively delivered curH to cells, where it was released. Other elemental distributions and caspase activities were consistent with preapoptotic activities. As such, 6 is a promising delivery agent for bioactive ligands, such as curH. However, pure curcumin itself showed a previously unrecognized ability to promote migration of A549 cells at subtoxic concentrations in the presence of endothelial growth factor, which may be a concern for its widespread use as a nutritional supplement and as a potential drug. This aspect warrants further research.

Evidence for the formation of SiGe nanoparticles in Ge-implanted Si3N4

Publisher: AIP Publishing

Date: 14-03-2017

DOI: 10.1063/1.4977507

Abstract: SiGe nanoparticles were formed in an amorphous Si3N4 matrix by Ge+ ion implantation and thermal annealing. The size of the nanoparticles was determined by transmission electron microscopy and their atomic structure by x-ray absorption spectroscopy. Nanoparticles were observed for excess Ge concentrations in the range from 9 to 12 at. % after annealing at temperatures in the range from 700 to 900 °C. The average nanoparticle size increased with excess Ge concentration and annealing temperature and varied from an average diameter of 1.8 ± 0.2 nm for the lowest concentration and annealing temperature to 3.2 ± 0.5 nm for the highest concentration and annealing temperature. Our study demonstrates that the structural properties of embedded SiGe nanoparticles in amorphous Si3N4 are sensitive to the implantation and post implantation conditions. Furthermore, we demonstrate that ion implantation is a novel pathway to fabricate and control the SiGe nanoparticle structure and potentially useful for future optoelectronic device applications.

Electrical and structural properties of In-implanted Si1-xGex alloys

Publisher: AIP Publishing

Date: 14-01-2016

DOI: 10.1063/1.4940046

Abstract: We report on the effects of dopant concentration and substrate stoichiometry on the electrical and structural properties of In-implanted Si1−xGex alloys. Correlating the fraction of electrically active In atoms from Hall Effect measurements with the In atomic environment determined by X-ray absorption spectroscopy, we observed the transition from electrically active, substitutional In at low In concentration to electrically inactive metallic In at high In concentration. The In solid-solubility limit has been quantified and was dependent on the Si1−xGex alloy stoichiometry the solid-solubility limit increased as the Ge fraction increased. This result was consistent with density functional theory calculations of two In atoms in a Si1−xGex supercell that demonstrated that In–In pairing was energetically favorable for x ≲ 0.7 and energetically unfavorable for x ≳ 0.7. Transmission electron microscopy imaging further complemented the results described earlier with the In concentration and Si1−xGex alloy stoichiometry dependencies readily visible. We have demonstrated that low resistivity values can be achieved with In implantation in Si1−xGex alloys, and this combination of dopant and substrate represents an effective doping protocol.

Australian Synchrotron

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Australian Synchrotron

Location: Australia

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Discovery Projects - Grant ID: DP0346163

Start Date: 04-2003

End Date: 12-2005

Amount: $249,500.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP140100176

Start Date: 2014

End Date: 12-2017

Amount: $519,790.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0984722

Start Date: 01-2009

End Date: 12-2014

Amount: $995,000.00

Funder: Australian Research Council