The properties of self-assembled phospholipid membranes are of essential importance in biochemistry and physical chemistry, providing a platform for many cellular life functions. Far-infrared (far-IR) vibrational spectroscopy, on the other hand, is a highly information-rich method to characterize intermolecular interactions and collective behaviour of lipids that can help explain, e.g., chain packing, thermodynamic phase behaviour, and sequestration. However, reliable interpretation of the far-IR spectra is still lacking. Here we present a molecular dynamics (MD) based approach to simulate vibrational modes of individual lipids and in an ensemble. The results are a good match to synchrotron far-IR measurements and enable identification of the molecular motions corresponding to each vibrational mode, thus allowing the correct interpretation of membrane spectra with high accuracy and resolving the longstanding ambiguities in the literature in this regard. Our results demonstrate the feasibility of using MD simulations for interpreting far-IR spectra broadly, opening new avenues for practical use of this powerful method. The far-IR vibrational spectrum of phospholipid calculated from molecular dynamics simulations inherently takes local and collective motions into account and facilitates assignment of functional groups to specific peaks in the experimental spectrum.

Nanoporous silver (np-S) was prepared by free corrosion dealloying of a series of Ag–Al thin films containing between 25 and 73 at.% Al. It was found that precursor composition had an important influence on the nanostructures and morphologies of the np-S. In particular the size of the Ag ligaments systematically decreased from 32 to 13 nm as the Al content was increased over the series. In contrast, there was only a weak effect on pore size, which remained in the range 11–15 nm, with the maximum occurring at about 55 at.% Al. There was however a significant increase in the density of the pores as the Al content of the precursor was increased. The electrical resistivity of the np-S increases with the decrease in ligament size, changing from about 3 × 10−8 Ω m for sponges with ligaments of about 32 nm diameter rising to 30 × 10−8 Ω m for the sponge with the 13 nm ligaments. The surface area of the np-S was estimated by the electrochemical capacitance in KNO3 solutions and was estimated to increase by an order of magnitude compared to a smooth Ag surface. There was a systematic change in the optical properties of the sponges, with a trend towards less metallic behaviour as the ligament size decreased and pore density increased. These changes culminated in the sponge prepared from the 73 at.% Al precursor having non-metallic characteristics with regard to visible and near-infrared light. The volume fraction of metal was estimated to be of the order of 40 ± 5%. Prior annealing of the precursor inhibited dealloying.

The formation of mesoporous gold sponges by explosive decomposition of 'knallgold' (also known as 'fulminating' gold) is studied. Proof-of-principle experiments are conducted and then the phenomena are further investigated using 'toy physics' molecular dynamics simulations. The simulations invoked various ratios of a volatile Lennard-Jones element G and a noble metal element N. In both experiment and simulation the morphology of the resulting sponge is found to depend on the stoichiometry of the starting material. As the mole fraction of G (χG) is increased from 0.5 to close to 1.0 in the simulations, the morphology of the sponges changes from closed to open, with a corresponding increase in the average mean curvature from 0 to +0.12 inverse Lennard-Jones length (L) units. The average Gaussian curvature of the simulated sponges is always negative, with the minimum value of 0.05 L-2 being found for χG≈0.65. In broad agreement with experiment, sponge formation in the simulations is bounded by stoichiometry; no sponges form if χG is <0.52, for χG between 0.52 and 0.70 the sponge is characterized by vermicular cavities whereas classic bicontinuous fibrous sponges form for 0.70<χG<0.85 and, finally, discrete particles result if χG>0.85.

A proof-of-principle double-layer symmetrical supercapacitor with nanoporous copper/copper oxide electrodes and an aqueous electrolyte is investigated. The electrodes are manufactured by selective dissolution of Al from a eutectic composition of Cu 17.5 Al 82.5 using 5 M NaOH. The ostensible (i.e., net external) capacitance of a symmetrical two-electrode cell with 0.1 M KNO 3 electrolyte is assessed over a series of charge/discharge cycles and is about 2 F per gram of Cu in this simple prototype. Capacitance varies during a discharge cycle due evidently to the deeply buried surfaces and pseudocapacitive reactions contributing charge toward the end of a discharge cycle. In principle such a device should have very low ohmic losses due to its highly conductive backbone and would be suitable for applications requiring maximum energy efficiency over repeated cycling. The aqueous electrolyte ensures fire safety but this comes at the cost of lower energy content. Graphical abstract

The solid-state phase transformation in nickel(II) bis-(diisopropyldithiocarbonate) is analyzed using a combination of highspeed in situ single-crystal diffraction, terahertz spectroscopy, optical microscopy, thermal analysis, and density functional theory. We show that the monoclinic P2(1)/c structure of this compound undergoes a displacive phase change at about 3 degrees C. The monoclinic angles and unit cell volumes change reversibly between 110.3 degrees/2265 angstrom(3) and 103.8 degrees/2168 angstrom(3). An analysis of atomic positions using high-resolution in situ synchrotron X-ray diffraction data revealed details of the atomic displacements that show a change in order that precedes and accompanies the change in structure. The structural changes are rapid and are manifested as reversible macroscale crystal movement and jumping (thermosalience) and represent the first case of thermosalience in dithiocarbamate complexes.

The purpose of this study is to design and evaluate the effectiveness of a mentoring program run for first year physics students. The mentoring program was initiated to address the low student retention in undergraduate physics courses. Preliminary surveys found a mismatch between student career identity and perceived relevance of physics. Mentoring has been shown to have a positive effect on mentees’ science identity, retention, and career planning by promoting science outcomes for the mentees and positive attitudes about science. This has been particularly effective for students belonging to underrepresented groups in science, who typically have lower science identity. Students became acquainted with the 20-member mentoring panel in a flash mentoring event. Mentors were partnered with two students and asked to spend an average of fifteen minutes per week in discussion with the students. Discussion topics were emailed weekly. Some of our learnings from this pilot program included doing a post questionnaire during class time to ensure a high completion rate. The main gains cited by mentees were increased motivation to study, new vision of future career and employment and an increase in the number of career relevant skills they would learn through their course.

Virtual reality (VR) is already providing the ability for students to have direct interactions with content in its ability to convert conceptual knowledge into reality. A VR environment can serve as a platform to further extend students understanding by allowing for exchangeable content that is co-created by students and their lecturers. We discuss how to achieve this using a modular VR platform which can be modified without needing VR programming expertise, containing customised content to create interactive learning experiences to serve various STEM subjects. For example, for students to study electromagnetism, a physics concept known to be difficult and counter-intuitive for students to understand, designing an environment where students can create and experience their own understanding is key. Here lecturers will provide a library of fields/operations and students draw from the library to see the phenomena in action, thus solving, testing and resolving interactions as a way to tacitly understand concepts. Having an environment that can be built to accommodate not only physics, but through scaffolded design allows students from chemistry, biochemistry or mathematics to be similarly engaged in the disciplinary content, creates transference not only between subjects but also into the real world.

The hydrozoan Millepora dichotoma (MD) is a typical Red Sea species containing a porous skeleton in the form of aragonite crystalline calcium carbonate. Due to environmental considerations, the artificial production of coralline species under controlled conditions is pertinent and underway. Artificially grown MD was used as a raw material for the production of calcium phosphate, mainly hydroxyapatite bioceramics, to be used in the drug delivery systems as a drug carrier or in the tissue engineering such as bone graft. DTA-TGA, XRD, FT-IR, Raman, and SEM analysis were carried out to analyze both unconverted and converted artificial corals. Hydrothermally converted coral fine powders were loaded with gentamicin (Gm) antibiotic, and the drug-loaded particles were analyzed by SEM. Unconverted coral was mainly aragonite, while hydrothermally treated coral was completely converted to hydroxyapatite. Hydrothermally treated coral was showing agglomerated nodules up to 1-μm size consisting of nanocrystalline hydroxyapatite platelets in the size range of less than 100 nm. The general macropore size of the coral was found to be appropriate for osteoid growth, which is 100 to 600 μm range. These artificially grown corals can be easily produced and used for bone growth and repair and other biomedical applications.

Effective compliance is a key element to the successful management of marine protected areas (MPAs), and requires a suite of tools to generate awareness of MPA rules, and monitor and regulate their use. Using vessel monitoring systems and creating geo-fences around MPA boundaries is an innovative approach to improve such awareness to vessel masters and commercial fishing licence holders with these systems on-board. In 2014, Parks Australia in partnership with the Australian Fisheries Management Authority (AFMA) introduced a purpose-built alert service for commercial fishing licence holders operating in Australian Commonwealth fisheries managed by AFMA that overlap with MPAs (Australian marine parks). The alert service is customised for each individual fishing vessel to notify masters and licence holders when they enter Australian marine parks where their particular fishing method is prohibited. Since the introduction of the alert service in 25 marine parks, fishers have received 3307 alerts, across eight fisheries. It is estimated that 23 of these alerts averted compliance incidents, in turn protecting marine park values and saving AUD$4.7 million in litigation costs. Of significance, there has been no recorded incidence of noncompliance by Australian commercial fishing licence holders and their vessel master's with access to the alert service since its introduction. The information presented here is the first empirical analysis of the effectiveness of geo-fencing to minimise noncompliance in MPAs. The alert service has the potential to become a front-line tool for supporting compliance by commercial fishing licence holders and their master's in Australian marine parks and other large-scale MPAs and MPA networks, globally.

The resolution of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) elemental bioimaging is usually constrained by the diameter of the laser spot size and is often not adequate to explore in situ subcellular distributions of elements and proteins in biological tissue sections. Super-resolution reconstruction is a method typically used for many imaging modalities and combines multiple lower resolution images to create a higher resolution image. Here, we present a super-resolution reconstruction method for LA-ICP-MS imaging by ablating consecutive layers of a biological specimen with offset orthogonal scans, resulting in a 10× improvement in resolution for quantitative measurement of dystrophin in murine muscle fibers. Layer-by-layer image reconstruction was also extended to the third dimension without the requirement of image registration across multiple thin section specimens. Quantitative super-resolution reconstruction, combined with Gaussian filtering and application of the Richardson-Lucy total variation algorithm, provided superior image clarity and fidelity in two- and three-dimensions.

A hybrid surfactant/polyoxometalate compound was synthesized by combining isopolytungstate anions with the cationic surfactant cetyltrimethylammonium bromide (CTA-Br) to produce a hierarchical compound that we identify as (CTA)7[H2W12O40]Cl·2H2O. At room temperature the compound consisted of hexagonally ordered sheets of Keggin ions, with an intervening gallery containing alkyl-chains of the organic cations. The synthesis was highly dependent on solution pH, reaction time and the order in which the reactants were added. We examined the effect of temperature on the stability of (CTA)7[H2W12O40]Cl·2H2O using thermal gravimetric analysis, differential scanning calorimetry, FT-IR spectroscopy and in situ synchrotron X-ray diffraction, and found a step-wise conversion to monoclinic WOxvia a series of intermediates. Heating under nitrogen atmospheres accelerated transition events by ∼100 °C when compared to heating in air. During heating, the interplanar gallery at first expanded in a series of steps starting at 90 °C as the CTA+ amphiphiles changed orientation, before collapsing rapidly at 240 °C, a temperature coinciding with the removal of about 40% of the organic material. Between 240 and 320 °C, the material consisted of fragments of the Keggin ion cores, arranged in 2D hexagonally-packed sheets. At ∼330 °C, the Keggin ions were completely destroyed and replaced by bulk W17O47 which, upon further heating, transformed to bulk WO2 or WO3 depending on the environment.

Large more reproducibly fabricated microstructures can also provide significant Raman signal enhancementviausually neglected multipolar plasmon resonances.

A gold nanoparticle (AuNP) ruthenium phthalocyanine (RuPc) nanocomposite has been synthesised that exhibits high thermal stability. Electrical resistance measurements revealed that the nanocomposite is stable up to ∼320 °C. Examination of the nanocomposite and the RuPc stabiliser complex using thermogravimetric analysis and differential scanning calorimetry show that the remarkable thermal stability is due to the RuPc molecules, which provide an effective barrier to sintering of the AuNPs.

Synchrotron far-infrared spectroscopy was used in conjunction with density functional theory vibrational analysis to ascertain the core structure of self-assembled fibrous superstructures formed by unnatural β3-tripeptides.

Abstract Peptides based on unnatural β3-amino acids offer a versatile platform for the design of self-assembling nanostructures due to the folding stability of the 14-helix and the high symmetry of the side chains inherent in this geometry. We have previously described that N-terminal acetylation (Ac-) forms a supramolecular self-assembly motif that allows β3-peptides to assemble head-to-tail into a helical nanorod which then further bundles into hierarchical superstructures. Here we investigate the effect of the topography of the 14-helical nanorod on lateral self-assembly. Specifically, we report on the variations in the superstructure of three isomeric peptides comprising the same three β3-amino acid residues: β3-leucine (L), β3-isoleucine (I) β3-alanine (A) to give peptides Ac-β3[LIA], Ac-β3[IAL] and Ac-β3[ALI]. AFM imaging shows markedly different superstructures for the three peptides. Well defined synchrotron far-infrared spectra reveal uniform geometries with a high degree of similarity between the isomeric peptides in the amide modes of the 400–650 wavenumber range. Far-IR also confirms that the C-terminal carboxyl group is free in the assemblies, thus it is solvated in the dispersant. Hence, the differences in the superstructures formed by the fibers are defined primarily by van der Waals energy minimization between the varied cross sectional morphologies of the core nanorods.

The combination of metal and semiconductor components in nanoscale to form a hybrid nanocrystal provides an important approach for achieving advanced functional materials with special optical, magnetic and photocatalytic functionalities. Here, a facile solution method is reported for the synthesis of Au-Ni-ZnO metal-semiconductor hybrid nanocrystals with a flower-like morphology and multifunctional properties. This synthetic strategy uses noble and magnetic metal Au@Ni nanocrystal seeds formed in situ to induce the heteroepitaxial growth of semiconducting ZnO nanopyramids onto the surface of metal cores. Evidence of epitaxial growth of ZnO{0001} facets on Ni {111} facets is observed on the heterojunction, even though there is a large lattice mismatch between the semiconducting and magnetic components. Adjustment of the amount of Au and Ni precursors can control the size and composition of the metal core, and consequently modify the surface plasmon resonance (SPR) and magnetic properties. Room-temperature superparamagnetic properties can be achieved by tuning the size of Ni core. The as-prepared Au-Ni-ZnO nanocrystals are strongly photocatalytic and can be separated and re-cycled by virtue of their magnetic properties. The simultaneous combination of plasmonic, semiconducting and magnetic components within a single hybrid nanocrystal furnishes it multifunctionalities that may find wide potential applications.

Silver is considered as one of the most desirable materials for plasmonic devices due to it having low loss, low epsilon2, across the visible spectrum. In addition, silver nanotriangles can self-assemble into complex structures that can include tip-totip or base-to-base arrangements. While the optical properties of tip-to-tip dimers of nanotriangles have been quite intensively studied, the geometric inverse, the base-to-base configuration, has received much less attention. Here we report the results of a computational study of the optical response of this latter configuration. Calculations were performed using the discrete dipole approximation. The effect of gap size and substrate are considered. The results indicate that the base-to-base configuration can sustain a strong coupled dipole and various multimode resonances. The pairing of the parallel triangle edges produces a strongly capacitive configuration and very intense electric fields over an extended volume of space. Therefore, the base-to-base configuration could be suitable for a range of plasmonic applications that require a strong and uniform concentration of electric field. Examples include refractometeric sensing or metal-enhanced fluorescence.

The intermetallic compounds AuAl2 and PtAl2 are colored purple and yellow respectively. In the past they have been prepared by bulk melting techniques or by co-deposition in a magnetron sputterer. Here, however, we investigate films of AuAl2, PtAl2 and (Au,Pt)Al2 prepared by sequential physical vapor deposition of the elements, followed by in situ solid-state reaction. The microstructure, dielectric functions, optical properties and thermal stability of the resulting films are characterized and compared to those prepared by bulk melting or co-deposition. The (Au,Pt)Al2 films show a color gamut that stretches from purple to brassy yellow depending on composition and microstructure. High temperature synchrotron X-ray diffraction experiments show that the (Au,Pt)Al2 phase is metastable, decomposing when heated above 420°C. In contrast, the pure AuAl2 or PtAl2 phases are stable to about 580°C before they oxidize or decompose. The alternative possibility of producing the purple-to-yellow color gamut by depositing optical stacks of very thin films of AuAl2 and PtAl2 is also assessed. Either scheme will provide a range of colors lying between those of the binary compound endpoints. Calculations predict that deposition of AuAl2 onto PtAl2 will produce more intense colors than vice versa, an unexpected finding that is worth further investigation.