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Nanoindentation tests and molecular dynamics (MD) simulations are conducted to investigate the effect of graphene (Gr) coating on the deformation behavior of a orientation copper (Cu) substrate. Distinct displacement burst (pop-in) is observed in the load-depth curve, which is due to the fracture of the Gr coating. Compared to bare Cu, the MD simulations indicate different dislocation activities at the Gr/Cu interface. The effect of image stress confinement on the glide of dislocations in Cu is considered to be the reason responsible for the increased hardness in the Gr/Cu system.

Rivers are viewed as major pathways of microplastic transport from terrestrial areas to marine ecosystems. However, there is paucity of knowledge on the dispersal pattern and transport of microplastics in river sediments. In this study, a three dimensional hydrodynamic and particle transport modelling framework was created to investigate the dispersal and transport processes of microplastic particles commonly present in the environment, namely, polyethylene (PE), polypropylene (PP), polyamide (PA), and polyethylene terephthalate (PET) in river sediments. The study outcomes confirmed that sedimental microplastics with lower density would have higher mobility. PE and PP are likely to be transported for a relatively longer distance, while PA and PET would likely accumulate close to source points. High water flow would transport more microplastics from source points, and high flow velocity in bottom water layer are suggested to facilitate the transport of sedimental microplastics. Considering the limited dispersal and transport, the study outcomes indicated that river sediments would act as a sink for microplastic pollutants instead of being a transport pathway. The patchiness associated with the hotspots of different plastic types is expected to provide valuable information for microplastic source tracking.

Rivers are regarded as sinks and pathways of plastic pollutants from terrestrial environments to various other aquatic systems such as lakes and oceans. Although extensive research has been conducted in recent years on microplastic pollution in river sediments, knowledge on the relationships between potential influential factors such as catchment characteristics and sediment properties, and microplastics occurrence in river sediments, is still considered an under-researched area. This study evaluated the influence of land use, population, and sediment particle size on the presence of microplastics abundance and types. Based on a Bayesian Network modelling approach to characterise the correlations between influencing factors and microplastics occurrence, it was evident that microplastics type had a positive correlation with different land use types and population. Catchment characteristics were found to play a more important role in influencing microplastics type than microplastics concentration. A statistically significant positive relationship was observed between microplastics concentration and clay particles which suggested that the occurrence of microplastics in sediments can be impacted by the presence of clay particles.

Polycaprolactone (PCL) is frequently used as the base polymer in scaffolds targeted for tissue engineering applications. However, in the absence of further surface modification, the lack of functional moieties on the PCL chain results in non-ideal surface properties of such scaffolds, especially in terms of the inability to tailor the presentation of functional ligands for directed cell adhesion and growth. The current study investigates gamma irradiation-induced grafting as a means of improving the biofunctionality of the PCL surface. The surface presentation of carboxylic acid groups on 2D PCL films could be tailored by changing the acrylic acid (AAc) concentration and/or the solvent during grafting, as evaluated from X-ray photoelectron spectroscopy (XPS). From data obtained using Raman spectroscopy, it was concluded that the penetration depth of the grafted pAAc was affected by the solvent system with a mixed water–methanol system yielding high penetration. Grafted samples displayed a decreased elastic modulus of the surface correlating with pAAc penetration depth, as shown by nano-indentation using atomic force microscopy (AFM). The most promising grafting conditions found for the 2D PCL films were then applied to 3D thermally induced phase separation (TIPS) scaffolds and it was demonstrated using XPS that equivalent levels of grafting of pAAc could be achieved throughout the whole depth of the scaffold. The scaffolds maintained their overall integrity after grafting, even though we observed a decrease in the compressive modulus by 20% after surface modification. These combined studies confirm the utility of this surface modification methodology for scaffolds targeted at tissue engineering and cell culture applications.

Synthetic rubber particles released from car tyres are expected to be an important type of microplastics in the environment, with road runoff and stormwater likely to transport tyre particles to the aquatic environment. Stormwater treatment wetlands are one of the key methods for treating road runoff and stormwater, but the presence and concentration of synthetic rubber microplastics from tyre particles in wetlands are largely unknown. In addition, constructed floating wetlands can be built using recycled PET plastic bottles, raising concerns about potential release of microplastics to the environment. In this study, we measured the concentrations of microplastics in water and sediment from the inlet and outlet of a stormwater floating treatment wetland on Queensland's Gold Coast. An average of 0.9 ± 0.3 and 4.0 ± 2.4 microplastic particles/L were detected in the water phase in the inlet and outlet samples, respectively. The sediment contained an average of 595 ± 120 and 320 ± 42 microplastic particles/kg dry sediment in inlet and outlet sediments, respectively. Between 15 and 38% of microplastics in the sediment were identified by FTIR as synthetic rubber-carbon filled particles, most likely derived from car tyres. The presence of synthetic rubber microplastics confirms that tyres can contribute to microplastic pollution in stormwater, with road runoff likely to be an important pathway. No microplastics with the same characteristics and polymer composition as the floating wetland construction material were detected in the water and sediment samples, indicating that the microplastics in the water and sediment detected here did not originate from the floating wetland's material. However, further investigation of older treatment wetlands is required to better understand the potential role of floating treatment wetlands as a source of microplastics.

We report on a spatial mapping of the electronic and vibrational structure of three-dimensional (3D) nanoporous graphene architectures, which have a hierarchical pore structure. We demonstrate that the topology, curvature, and pores lead to local changes in the electronic and vibrational structure and in the hybridization states of the carbon atoms (sp2 vs. sp3-like). Nitrogen substitutions in pyrrolic bonding configurations also contribute to local distortions of the planar geometry of graphene. The distortions influence the electronic density of states at the Fermi level by shifting the Dirac cone apex, opening potential avenues for applications of two-dimensional graphene in 3D devices.

Wastewater effluent is expected to be a pathway for microplastics to enter the aquatic environment, with microbeads from cosmetic products and polymer fibres from clothes likely to enter wastewater treatment plants (WWTP). To date, few studies have quantified microplastics in wastewater. Moreover, the lack of a standardized and applicable method to identify microplastics in complex samples, such as wastewater, has limited the accurate assessment of microplastics and may lead to an incorrect estimation. This study aimed to develop a validated method to sample and process microplastics from wastewater effluent and to apply the developed method to quantify and characterise wastewater-based microplastics in effluent from three WWTPs that use primary, secondary and tertiary treatment processes. We applied a high-volume sampling device that fractionated microplastics in situ and an efficient sample processing procedure to improve the sampling of microplastics in wastewater and to minimize the false detection of non-plastic particles. The sampling device captured between 92% and 99% of polystyrene microplastics using 25 μm-500 μm mesh screens in laboratory tests. Microplastic type, size and suspected origin in all studied WWTPs, along with the removal efficiency during the secondary and tertiary treatment stages, was investigated. Suspected microplastics were characterised using Fourier Transform Infrared spectroscopy, with between 22 and 90% of the suspected microplastics found to be non-plastic particles. An average of 0.28, 0.48 and 1.54 microplastics per litre of final effluent was found in tertiary, secondary and primary treated effluent, respectively. This study suggests that although low concentrations of microplastics are detected in wastewater effluent, WWTPs still have the potential to act as a pathway to release microplastics given the large volumes of effluent discharged to the aquatic environment. This study focused on a single sampling campaign, with long-term monitoring recommended to further characterise microplastics in wastewater.

N-type semiconducting molybdenum trioxide (MoO3) nanoparticles embedded in polyethylene oxide (PEO) polymer ultra-fine fibres were deposited directly onto silicon substrates using an electrospinning technique. The effects of different MoO3/PEO concentrations as well as electrospinning parameters on the fibre morphologies were examined. Experimental results show that embedding nanoparticles and electrospinning onto small areas can be achieved without use of solvents or transfer of the deposited nanostructures. This approach offers a cost effective fabrication method to produce a diverse range of multifunctional materials for many applications including electronics, mechanical enhancement, drug delivery and gas sensing. Keywords: Electrospinning, MoO3 nanoparticles (NPs), Poly(ethylene oxide), FESEM, TEM, FT-IR

Canga is a moderately hard iron-rich duricrust primarily composed of goethite as a result of the weathering of banded iron formations. Canga duricrusts lack a well-developed soil profile and consequently form an innate association with rupestrian plants that may become ferruginised, contributing to canga possessing macroscopic biological features. Examination of polished canga using a field emission scanning electron microscope (FE-SEM) revealed the biological textures associated with canga extended to the sub-millimetre scale in petrographic sections and polished blocks. Laminae that formed by abiotic processes and regions where goethite cements were formed in association with microorganisms were observed in canga. Biological cycling of iron within canga has resulted in two distinct forms of microbial fossilisation: permineralisation of multispecies biofilms and mineralisation of cell envelopes. Goethite permineralised biofilms frequently formed around goethite-rich kaolinite grains in close proximity to goethite bands and were composed of micrometre-scale rod-shaped, cocci and filamentous microfossils. In contrast, the cell envelopes immobilised by authigenic iron oxides were primarily of rod-shaped microorganisms, were not permineralised and occurred in pore spaces within canga. Complete mineralisation of intact rod-shaped casts and the absence of permineralisation suggested mineralised cell envelopes may represent fossilised iron-oxidising bacteria in the canga ecosystem. Replication of these iron-oxidising bacteria appeared to infill the porous regions within canga. Synchrotron-based Fourier transform infrared (FTIR) microspectroscopy demonstrated that organic biomarkers were poorly preserved with only weak bands indicative of aliphatic methylene (CH2) associated with permineralised microbial biofilms. High resolution imaging of microbial fossils in canga that had been etched with oxalic acid supported the poor preservation of organic biomarkers within canga, indicating mineralogical replacement of organic biomarkers.

Purpose: This study describes the development and characterization of glucagon dry powder inhaler (DPI) formulation for pulmonary delivery. Lactose monohydrate, as a carrier, and L-leucine and magnesium stearate (MgSt) were used as dispersibility enhancers for this formulation. Methods: Using Fourier-transform infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), and Raman confocal microscopy, the interactions between glucagon and all excipients were characterized. The fine particle fractions (FPFs) of glucagon in different formulations were determined by a twin stage impinger (TSI) using a 2.5% glucagon mixture, and the glucagon concentration was measured by a validated LC-MS/MS method. Results: The FPF of the glucagon was 6.4%, which increased six-fold from the formulations with excipients. The highest FPF (36%) was observed for the formulation containing MgSt and large carrier lactose. The FTIR, Raman, and DSC data showed remarkable physical interactions of glucagon with leucine and a minor interaction with lactose, however, there were no interactions with MgSt alone or mixed with lactose. Conclusion: Due to the interaction between L-leucine and glucagon, leucine was not a suitable excipient for glucagon formulation. In contrast, the use of lactose and MgSt could be considered to prepare an efficient DPI formulation for the pulmonary delivery of glucagon.

Mineralization of bone is a dynamic process, involving a complex interplay between cells, secreted macromolecules, signaling pathways, and enzymatic reactions; the dysregulation of bone mineralization may lead to serious skeletal disorders, including hypophosphatemic rickets, osteoporosis, and rheumatoid arthritis. Very few studies have reported the role of osteocytes - the most abundant bone cells in the skeletal system and the major orchestrators of bone remodeling in bone mineralization, which is owed to their nature of being deeply embedded in the mineralized bone matrix. The Wnt/β-catenin signaling pathway is actively involved in various life processes including osteogenesis; however, the role of Wnt/β-catenin signaling in the terminal mineralization of bone, especially in the regulation of osteocytes, is largely unknown. This research demonstrates that during the terminal mineralization process, the Wnt/β-catenin pathway is downregulated, and when Wnt/β-catenin signaling is activated in osteocytes, dendrite development is suppressed and the expression of dentin matrix protein 1 (DMP1) is inhibited. Aberrant activation of Wnt/β-catenin signaling in osteocytes leads to the spontaneous deposition of extra-large mineralized nodules on the surface of collagen fibrils. The altered mineral crystal structure and decreased bonding force between minerals and the organic matrix indicate the inferior integration of minerals and collagen. In conclusion, Wnt/β-catenin signaling plays a critical role in the terminal differentiation of osteocytes and as such, targeting Wnt/β-catenin signaling in osteocytes may serve as a potential therapeutic approach for the management of bone-related diseases.

Demonstrating the biogenicity of presumptive microfossils in the geological record often requires supporting chemical signatures, including isotopic signatures. Understanding the mechanisms that promote the preservation of microbial biosignatures associated with microfossils is fundamental to unravelling the palaeomicrobiological history of the material. Organomineralization of microorganisms is likely to represent the first stages of microbial fossilisation and has been hypothesised to prevent the autolytic degradation of microbial cell envelope structures. In the present study, two distinct fossilisation textures (permineralised microfossils and iron oxide encrusted cell envelopes) identified throughout iron-rich rock samples were analysed using nanoscale secondary ion mass spectrometry (NanoSIMS). In this system, aluminium is enriched around the permineralised microfossils, while iron is enriched within the intracellularly, within distinct cell envelopes. Remarkably, while cell wall structures are indicated, carbon and nitrogen biosignatures are not preserved with permineralised microfossils. Therefore, the enrichment of aluminium, delineating these microfossils appears to have been critical to their structural preservation in this iron-rich environment. In contrast, NanoSIMS analysis of mineral encrusted cell envelopes reveals that preserved carbon and nitrogen biosignatures are associated with the cell envelope structures of these microfossils. Interestingly, iron is depleted in regions where carbon and nitrogen are preserved. In contrast aluminium appears to be slightly enriched in regions associated with remnant cell envelope structures. The correlation of aluminium with carbon and nitrogen biosignatures suggests the complexation of aluminium with preserved cell envelope structures before or immediately after cell death may have inactivated autolytic activity preventing the rapid breakdown of these organic, macromolecular structures. Combined, these results highlight that aluminium may play an important role in the preservation of microorganisms within the rock record. Keywords: Aluminium, Microfossils, Biosignatures, NanoSIMS, Organomineralisation

The evolution of iron-rich duricrusts (canga) that cap weathered banded iron formations (BIFs) in the Serra Sul de Carajas, northern Brazil, has been essential to armour these landscapes, allowing for the enrichment and preservation of world class iron ore deposits. Bulk chemical data highlight an incorporation of exogenous materials into secondary cements, including aluminium, phosphorus, silicon, titanium, vanadium and zirconium. The incorporation of these materials within the canga cements highlights the continuous formation of secondary cements within canga, which entrap these materials. Microfossils identified throughout the canga profiles indicates microorganisms are likely to have contributed to mineral weathering, metal mobility and biomineralisation. X-ray fluorescence microscopy (XFM) analysis of canga subsamples revealed titanium mobility in close proximity to preserved microfossils. Microbially accelerated mineral weathering appears to place titanium into solution, which reprecipitates as microcrystalline anatase within the goethitic cements that forms rims around some grains. These results demonstrate the mobility of titanium within duricrusts, which is likely to be influenced by organic acids. Canga evolution was investigated using X-ray absorption near edge structure (XANES) analysis combined with bulk chemical extractions. These experiments demonstrate that hematite (martite) fragments are enriched in ferrous iron, which is released during acid-induced weathering. This ferrous iron is likely to be maintained in microscale magnetite inclusions within the martite. These data support the nonredox transition of magnetite to martite (likely via a ferrous iron-deficient magnetite (for example, kenomagnetite)). The ferrous iron released during the weathering of magnetite-bearing rocks provides an iron source for the generation of new cements within canga. These insights have implications for choosing starting materials for the re-cementation of iron-rich duricrusts after the completion of iron ore mining in Brazil.

Calcium phosphate apatite, Ca5 (PO4)3(OH,F,Cl), is a common accessory mineral in coal seams. Although minor, its role in hosting phosphorus (P) and fluorine (F) can reduce the economic viability of coking and thermal coal deposits. Apatite in coal is commonly 1 wt%. However, the small crystallite size of the encrusting-apatites and the pits on the polished surface of the detrital-apatites intermixed with the coal layers hindered determining the halogens by this method. Although, all of the apatites in the coals were able to be analysed by infrared spectroscopy, both the combined kaolinite and apatite spectra, and the noise in the spectra at the lower wavelengths hindered evaluating the F in the apatites using this method. Despite these limitations, the findings of this study show that EPMA is probably the most suitable analytical technique for determining the halogen contents of the different modes of apatites in situ in coal pellets. Future work should focus on determining whether the modes of occurrence reflect paragenesis.

We report the synthesis and characterisation of new examples of meso-hydroxynickel(II) porphyrins with 5,15-diphenyl and 10-phenyl-5,15-diphenyl/diaryl substitu- tion. The OH group was introduced by using carbonate or hydroxide as nucleophile by using palladium/phosphine cat- alysis. The NiPor OHs exist in solution in equilibrium with the corresponding oxy radicals NiPor OC. The 15-phenyl group stabilises the radicals, so that the 1H NMR spectra of {NiPor OH} are extremely broad due to chemical exchange with the paramagnetic species. The radical concentration for the diphenylporphyrin analogue is only 1%, and its NMR line-broadening was able to be studied by variable-tempera- ture NMR spectroscopy. The EPR signals of NiPor OC are con- sistent with somewhat delocalised porphyrinyloxy radicals, and the spin distributions calculated by using density func- tional theory match the EPR and NMR spectroscopic obser- vations. Nickel(II) meso-hydroxy-10,20-diphenylporphyrin was oxidatively coupled to a dioxo-terminated porphodimethene dyad, the strongly red-shifted electronic spectrum of which was successfully modelled by using time-dependent DFT calculations.

The X-ray crystal structure of trans-di-t-butyl azodicarboxylate (DTBAD, 2) was determined and this revealed that the torsion angle between the N N and C O double bonds is 84.0(2)°, and that between the anti-disposed C O vectors is 180°. This is the first report of the solid state structure of an azodicarboxylate ester. The molecule was subjected to Density Functional Theory geometry optimization at the B3LYP/6-31G(d) level in cyclohexane medium, and the global minimum structure agreed in principle with that determined in the solid state by crystallography. The N–C(O) torsion angle in the optimized structure is 107.7°, and the C O vectors lie in an anti relationship. Similar calculations on the unknown cis-N N isomer revealed an optimum geometry whose energy is predicted to lie only 11.9 kJ/mol higher than that of the trans isomer. M062X/6-311+G(d) model chemistry was used to determine relative electronic energies and to conduct Natural Bond Orbital (NBO) calculations. Exploration of the energetics of rotations about the N–C(O) bonds revealed a clear preference for near-orthogonality in azodicarboxylates, and suggests almost complete absence of classical conjugation between the neighbouring π bonds. Electronic transitions were simulated using the time-dependent DFT (TD-DFT) approach at the B3LYP/6-311+G(d) level, and the weak band in the near-UV for 2 in cyclohexane was reproduced in the calculations. The electronic isolation of the N N bond may be important in the numerous applications of azodicarboxylates in organic synthesis, and the small energy difference between the trans and cis isomers implies the likely involvement of the latter in the successful photochemical diaza-Diels–Alder reaction of diethyl azodicarboxylate with 1,3-cyclohexadiene.

Meropenem (MPN), a broad spectrum β-lactam antibiotic, has been increasingly used in the treatment of moderate to severe bacterial infections. However, due to its short plasma half-life and chemical instability in solution form, it has been challenging to use in the intravenous formulation. This study aims to develop and characterize MPN dry powder inhaler (DPI) formulation for pulmonary delivery. The inhalable MPN particles (1-5µm) were prepared by micronization. Lactose, L-leucine and magnesium stearate (MgSt) were used in the powder formulation as carriers and dispersibility enhancers. The formulations were characterized by Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman confocal microscopy, X-Ray powder diffraction analysis (PXRD), and differential scanning calorimetry (DSC) methods. The concentration of MPN was determined by using a validated HPLC method. The Fine Particle Fraction (FPF) of meropenem from powder mixtures was determined by a Twin Stage Impinger (TSI) at a flow rate of 60 L/min. The FPF of the original MPN was 1.91 % which was significantly increased to 37.5 % for the formulations with excipients. No physical interactions between the drug and the excipients observed. This study revealed the potential of a stable meropenem DPI formulation for pulmonary delivery.

Microplastics pose threats to aquatic environments because they serve as hard-substrate for microbial community colonization and biofilm formation due to their long-life span and hydrophobic surface which can impact on aquatic ecosystems. However, the association between microplastics and other pollutants, particularly nutrients and metals in river sediments are largely unknown. In this study, microplastics abundance and hazard scores which are the risks arising from chemical compounds used for plastics manufacture, and the correlations between microplastics and the concentrations of total carbon (TC), total nitrogen (TN), total phosphorus (TP) and metals commonly present in the urban environment such as Al, As, Cr, Co, Cu, Fe, Mg, Mn, Ni, Cd, Se, Sr, Zn, Pb, in Brisbane River sediments were investigated. The study confirmed that the risk associated with microplastics is based on their monomer composition rather than the quantities present. Sediments having relatively higher abundance of microplastics with a relatively lower hazard score result in higher nutrient concentrations. The concentrations of metals in river sediments are more dependent on their original sources rather than the concentration of microplastics. Nevertheless, leachate from plastics should be considered in risk assessment in relation to the association between metals and plastics in aquatic environments.

Iron-rich duricrusts (canga) that blanket iron ore deposits in tropical regions in Brazil have a complex formation and evolution. The direct role of microorganisms in the biogeochemical cycling of iron and remarkably aluminium, which is critical for the preservation of these duricrusts, is becoming more apparent. In this study we combine nanoscale secondary ion mass spectrometry (NanoSIMS) with Raman spectroscopy and scanning electron microscopy to distinguish highly weathered and recycled grains, portions of which have been metasomatised by iron in solution, from new mineral precipitates within canga. Microbially-accelerated weathering of grains within canga appears to promote iron, aluminium and titanium oxide mineral dissolution. Anatase forms at the boundaries of rutile grains, highlighting titanium dissolution and re-precipitation at the mineral-scale. Titanium is absent from the authigenic cements in canga. Aqueous ferrous iron, which is sensitive to changes in the oxidation potential of the solution, readily oxidises and re-precipitates in the pore spaces in proximity to preserved microorganisms, leaving aluminium as the most abundant cation in solution. Changes in solution pH and/or organic chemistry causes aluminium to precipitate from solution as gibbsite that infills pore spaces as the final geological texture. Evidence for microbially-promoted weathering includes the fossilisation of microorganisms along grain boundaries, in which aluminium, titanium, chromium and iron are depleted. Immobile elements including titanium, chromium and thorium, associated with rounded fossilised biofilms also indicate that microorganisms have completely weathered grains and become fossilised in place, texturally replacing the grain in the process. Microorganisms also play a role in iron and aluminium precipitation, providing sites for mineral nucleation. These results highlight the microscale changes in oxidation potential, pH and organic chemistry throughout canga that are likely to be influenced by the microbiome and associated flora. Understanding the role of microorganisms in iron biogeochemical cycling will contribute to the accelerated re-cementation of iron-rich duricrusts after the completion of iron ore mining, providing a substrate for revegetation using native plant species. This study also sheds light on direct (microfossils) and indirect (biologically-influenced element mobility) biosignatures in iron-rich geological materials.

Anomalous peaks were observed during attempts to measure micro-ATR infrared spectra of small domains (>30 μm) of the mineral apatite that were associated with coal particles in polished epoxy grain mounts. The peaks were sharp, variable in intensity, and appeared near the high wavenumber edge of the broad ν3 band of the phosphate. Similar effects were observed in single crystals of quartz, garnet and calcite. The manifestation of these peaks was associated with experimental factors that rendered a small gap between the ATR tip and the sample. They were assigned to surface phonon polaritons (SPhPs) owing to their explicit requirement of non-contact between sample and ATR objective, their position in relation to the longitudinal optic limit of the reststrahlen bands of the crystalline materials, and their wavenumber dependence on the refractive index of the intermediating dielectric, as predicted by SPhP theory. In this paper we establish three conditions under which SPhPs can be accidentally or unintentionally excited: when the IR beam of the microscope is not well aligned; when optical contact between the mineral and ATR objective is poor; and when the surface of the sample is not normal to the optical axis of the microscope. The object of this paper was not to study SPhPs as such, but to raise awareness amongst FT-IR ATR practitioners that SPhP peaks can interfere if their experimental conditions are less than ideal, particularly in the case of polished geological sections and minerals.

Plastic pollutants in aquatic ecosystems have received wide attention and research endeavours since early 1970s. However, in comparison to marine environments, the occurrence of microplastics in a tidal river system remains largely unknown, especially in river sediments. Sediment samples taken from twenty-two sampling points along Brisbane River over the four different seasons revealed relatively high concentrations of microplastics in river sediments, with abundance ranging from 0.18 to 129.20 mg kg−1, or 10 to 520 items kg−1. Unfortunately, varied methods and units used for reporting do not allow the accurate comparison between related studies. The spatial distributions of microplastics hotspots indicated that microplastics abundance is distance-dominated caused by flow velocities. Lower and higher concentrations of microplastics abundance mostly occurred in dry and wet seasons, respectively. Significant temporal variations of microplastics concentrations was observed in residential and commercial areas. Polyethylene (PE), polyamide (PA) and polypropylene (PP), were the three main polymer types found in the Brisbane River sediments. Other polymer types such as polyethylene terephthalate (PET) were also detected. The majority of the detected microplastic particles were found to be

This study demonstrates the preparation and characterization of ibuprofen (IBP) microparticles with some excipients by a controlled crystallization technique with improved dissolution performance. Using the optimum concentrations pluronic F127, hydroxypropyl methyl cellulose, D-mannitol, and l-leucine in aqueous ethanol, the IBP microparticles were prepared. The dissolution tests were performed in phosphate buffer saline using a United States Pharmacopoeia dissolution tester at 37°C. The Raman spectroscopy was used to investigate the interactions and distribution of the IBP with the additives in the microcrystals. The prepared IBP microparticles showed higher dissolution compared to that of the smaller sized original IBP particles. The Raman data revealed that the excipients with a large number of hydroxyl groups distributed around the IBP particle in the crystal enhanced the dissolution of the drug by increasing the drug-solvent interaction presumably through hydrogen bonding. The Raman mapping technique gave an insight into the enhanced dissolution behavior of the prepared IBP microparticles, and such information will be useful for developing pharmaceutical formulations of hydrophobic drugs. The controlled crystallization was a useful technique to prepare complex crystals of IBP microparticles along with other additives to achieve the enhanced dissolution profile.

The influence of graphene oxide (GO) and its surface oxidized debris (OD) on the cure chemistry of an amine cured epoxy resin has been investigated by Fourier Transform Infrared Emission Spectroscopy (FT-IES) and Differential Scanning Calorimetry (DSC). Spectral analysis of IR radiation emitted at the cure temperature from thin films of diglycidyl ether of bisphenol A epoxy resin (DGEBA) and 4,4'-diaminodiphenylmethane (DDM) curing agent with and without GO allowed the cure kinetics of the interphase between the bulk resin and GO to be monitored in real time, by measuring both the consumption of primary (1°) amine and epoxy groups, formation of ether groups as well as computing the profiles for formation of secondary (2°) and tertiary (3°) amines. OD was isolated from as-produced GO (aGO) by a simple autoclave method to give OD-free autoclaved GO (acGO). It has been found that the presence of OD on the GO prevents active sites on GO surfaces fully catalysing and participating in the reaction of DGEBA with DDM, which results in slower reaction and a lower crosslink density of the three-dimensional networks in the aGO-resin interphase compared to the acGO-resin interphase. We also determined that OD itself promoted DGEBA homopolymerization. A DSC study further confirmed that the aGO nanocomposite exhibited lower Tg while acGO nanocomposite showed higher Tg compared to neat resin because of the difference in crosslink densities of the matrix around the different GOs.

We report for the first time the ingestion of microplastics by scleractinian corals, and the presence of microplastics in coral reef waters adjacent to inshore reefs on Australia’s Great Barrier Reef (GRE, 18°31′S 146°23′E). Analysis of samples from sub-surface plankton tows conducted in close proximity to inshore reefs on the central GBR revealed microplastics, similar to those used in marine paints and fishing floats, were present in low concentrations at all water sampling locations. Experimental feeding trials revealed that corals mistake microplastics for prey and can consume up to ~50 μg plastic cm−2 h−1, rates similar to their consumption of plankton and Artemia nauplii in experimental feeding assays. Ingested microplastics were found wrapped in mesenterial tissue within the coral gut cavity, suggesting that ingestion of high concentrations of microplastic debris could potentially impair the health of corals.

One-dimensional single crystal incorporating functional nanoparticles of other materials could be an interesting platform for various applications. We studied the encapsulation of nanoparticles into single-crystal ZnO nanorods by exploiting the crystal growth of ZnO in aqueous solution. Two types of nanodiamonds with mean diameters of 10 nm and 40 nm, respectively, and polymer nanobeads with size of 200 nm have been used to study the encapsulation process. It was found that by regrowing these ZnO nanorods with nanoparticles attached to their surfaces, a full encapsulation of nanoparticles into nanorods can be achieved. We demonstrate that our low-temperature aqueous solution growth of ZnO nanorods do not affect or cause degradation of the nanoparticles of either inorganic or organic materials. This new growth method opens the way to a plethora of applications combining the properties of single crystal host and encapsulated nanoparticles. We perform micro-photoluminescence measurement on a single ZnO nanorod containing luminescent nanodiamonds and the spectrum has a different shape from that of naked nanodiamonds, revealing the cavity effect of ZnO nanorod.

The synthesis, electronic absorption and 1H NMR spectra of a suite of novel porphyrinoids derived from meso-bromoporphyrins by palladium-catalysed aminations using ethyl and tert-butylcarbazates are reported. Instead of the expected carbazate-substituted porphyrins, a facile oxidative dearomatisation of the porphyrin ring occurs in high yield, especially for the nickel(II) complexes, resulting in high yields of 5,15-diiminoporphodimethenes (DIPDs). The analogous zinc(II) and free base DIPDs were also characterised, the former by X-ray crystallography. The oxidation and reduction reactions of DIPDs and their precursor carbazate porphyrins were studied. Density Functional Theory (DFT) was used to calculate the optimised geometries and frontier molecular orbitals of DIPD Ni8c and bis(azocarboxylate) 19c, and Time Dependent DFT calculations allowed the prediction of electronic absorption spectra, whose characteristics corresponded well with those of the observed solution spectra. In the latter case, the calculated low-energy absorptions were unlike those of a typical porphyrin, due to the near-degeneracy of the highest filled frontier orbitals, and the wide energy separation between the unfilled orbitals. This feature was present in the observed spectrum.

Single-crystal Raman spectroscopy of natural finnemanite and comparison with its synthesised analogue

The single crystal Raman spectra of natural mineral schafarzikite FeSb2O4 from the Pernek locality of the Slovak Republic are presented for the first time. Raman spectra of natural mineral apuanite Fe2+Fe43+Sb4O12S, originating from the Apuan Alps in Italy, as well as spectra of synthetic ZnSb2O4 and arsenite mineral trippkeite CuAs2O4 are also presented for the first time. The spectra of the antimonite minerals are characterized by a strong band in the region 660 – 680 cm-1 with shoulders on either side, and a band of medium intensity near 300 cm-1. The spectrum of the arsenite mineral is characterized by a medium band near 780 cm-1 with a shoulder on the high wavenumber side and a strong band at 370 cm-1. Assignments are proposed based on the spectral comparison between the compounds, symmetry modes of the bands and prior literature. The single crystal spectra of schafarzikite showed good mode separation, allowing bands to be assigned a symmetry species of A1g, B1g, B2g or Eg.

The oriented single-crystal Raman spectrum of leiteite has been obtained and the spectra related to the structure of the mineral. The intensities of the observed bands vary according to orientation, allowing them to be assigned to either Ag or Bg modes. Ag bands are generally the most intense in the CAAC spectrum, followed by ACCA, CBBC, and ABBA whereas Bg bands are generally the most intense in the CBAC followed by ABCA. The CAAC and ACCA spectra are identical, as are those obtained in the CBBC and ABBA orientations. Both cross-polarised spectra are identical. Band assignments were made with respect to bridging and non-bridging AsO bonds. Copyright © 2010 John Wiley & Sons, Ltd.

The single-crystal Raman spectra of minerals brandholzite and bottinoite, formula M[Sb(OH)6]2•6H2O, where M is Mg+2 and Ni+2, respectively, and the non-aligned Raman spectrum of mopungite, formula Na[Sb(OH)6], are presented for the first time. The mixed metal minerals comprise alternating layers of [Sb(OH)6]−1 octahedra and mixed [M(H2O)6]+2/[Sb(OH)6]−1 octahedra. Mopungite comprises hydrogen-bonded layers of [Sb(OH)6]−1 octahedra linked within the layer by Na+ ions. The spectra of the three minerals were dominated by the SbO symmetric stretch of the [Sb(OH)6]−1 octahedron, which occurs at approximately 620 cm−1. The Raman spectrum of mopungite showed many similarities to spectra of the di-octahedral minerals, supporting the view that the Sb octahedra give rise to most of the Raman bands observed, particularly below 1200 cm−1. Assignments have been proposed on the basis of the spectral comparison between the minerals, prior literature and density functional theory (DFT) calculations of the vibrational spectra of the free [Sb(OH)6]−1 and [M(H2O)6]+2 octahedra by a model chemistry of B3LYP/6-31G(d) and lanl2dz for the Sb atom. The single-crystal spectra showed good mode separation, allowing most of the bands to be assigned to the symmetry species A or E. Copyright © 2010 John Wiley & Sons, Ltd.

The arthropod cuticle is a remarkable and versatile biological material commonly composed of chitin and proteins. Lessons can be learned from the way it is adapted to fit its functions. The larval jewel beetle, Pseudotaenia frenchi, demonstrates hardness in the cutting edge of the mandibles in excess of the mineralized carapace of stone crabs and compares favourably with some stainless steels. Yet this is a form of cuticle which is devoid of transition metals or mineralization. In seeming contradiction, the similarly dark coloured adult beetle mandibles contain the transition metal manganese, but are significantly softer. Energy dispersive X-ray analysis and infrared spectroscopy have been used to investigate the differences in composition of mandible cuticle of the adult and larval beetles.

SummaryObjectiveTo compare collagen fibre alignment angles obtained from polarised light microscopy (PLM) and diffusion-tensor imaging (DTI) in bovine articular cartilage.MethodsFive samples of bovine articular cartilage from five different animals were studied using magnetic resonance imaging and PLM techniques. T2-weighted, diffusion-tensor (DT), and PLM images were acquired for each sample and average depth profiles of the PLM and DTI angles, as well as the banding patterns observed in T2-weighted magnetic resonance (MR) images, were compared. Statistical properties of the distributions of the DTI and PLM angles were examined.ResultsThe samples exhibited a range of alignment morphologies. In the samples with the “conventional” three-zone alignment pattern, a correlation between the PLM and DTI alignment zones and the banding in T2-weighted MR images was observed. The shapes of the depth profiles of the PLM and DTI alignment angles were qualitatively similar for each sample. Three samples showed good quantitative correlation between the DT and PLM alignment angles. The correlation between the diffusion and PLM alignment angles was best in the regions of low degree of disorder of fibre alignment.ConclusionsThis study provides the first quantitative comparison of DTI of cartilage with the more established PLM techniques. The correlation between alignment angles derived from PLM and DTI data was evident across a wide range of alignment morphologies. The results support the use of DTI for the quantitative measurement of collagen fibre alignment. The microscopic-scale (∼10μm) dispersion of fibre alignment angles appears to be an important factor for understanding the extent of quantitative correlation between PLM and DTI results.

Fourier transform infrared (FT-IR) attenuated total reflection (ATR) imaging has been successfully used to identify individual mineral components of ancient Maya paint. The high spatial resolution of a micro FT-IR-ATR system in combination with a focal plane array detector has allowed individual particles in the paint to be resolved and identified from their spectra. This system has been used in combination with micro-Raman spectroscopy to characterize the paint, which was found to be a mixture of hematite and silicate particles with minor amounts of calcite, carbon, and magnetite particles in a sub-micrometer hematite and calcite matrix. The underlying stucco was also investigated and found to be a combination of calcite with fine carbon particles, making a dark sub-ground for the paint.

Blends of starch and a biodegradable polyester, produced by an extrusion process which included a cross-linker/compatibilizer (maleic anhydride) and an initiator (dicumyl peroxide), were studied by infrared (IR) microspectroscopy using an attenuated total reflectance (ATR) objective. Extruded material, which had a diameter of about 3 mm, was sectioned and embedded in epoxy resin prior to IR analysis. Spectra were collected in a grid pattern across the sectioned face of the sample. Measurement of various band parameters from the spectra allowed IR maps to be constructed containing semi-quantitative information about the distribution of blend components. These maps showed the quality of the blend on a microscopic scale and showed how it varied with different concentrations of compatibilizer and initiator.

The infrared (IR) spectroscopic data and Raman spectroscopic properties for a series of 13 “pinwheel-like” homoleptic bis(phthalocyaninato) rare earth complexes M[Pc(α-OC5H11)4]2 [M = Y and Pr–Lu except Pm; H2Pc(α-OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine] have been collected and comparatively studied. Both the IR and Raman spectra for M[Pc(α-OC5H11)4]2 are more complicated than those of homoleptic bis(phthalocyaninato) rare earth analogues, namely M(Pc)2 and M[Pc(OC8H17)8]2, but resemble (for IR) or are a bit more complicated (for Raman) than those of heteroleptic counterparts M(Pc)[Pc(α-OC5H11)4], revealing the decreased molecular symmetry of these double-decker compounds, namely S8. Except for the obvious splitting of the isoindole breathing band at 1110–1123 cm−1, the IR spectra of M[Pc(α-OC5H11)4]2 are quite similar to those of corresponding M(Pc)[Pc(α-OC5H11)4] and therefore are similarly assigned. With laser excitation at 633 nm, Raman bands derived from isoindole ring and aza stretchings in the range of 1300–1600 cm−1 are selectively intensified. The IR spectra reveal that the frequencies of pyrrole stretching and pyrrole stretching coupled with the symmetrical CH bending of –CH3 groups are sensitive to the rare earth ionic size, while the Raman technique shows that the bands due to the isoindole stretchings and the coupled pyrrole and aza stretchings are similarly affected. Nevertheless, the phthalocyanine monoanion radical Pc′− IR marker band of bis(phthalocyaninato) complexes involving the same rare earth ion is found to shift to lower energy in the order M(Pc)2 > M(Pc)[Pc(α-OC5H11)4] > M[Pc(α-OC5H11)4]2, revealing the weakened π–π interaction between the two phthalocyanine rings in the same order.

Members of the solid-solution series between erythrite [Co3(AsO4)2·8H2O] and annabergite [Ni3(AsO4)2·8H2O] were synthesized and studied by a combination of X-ray diffraction, scanning electron microscopy, and Raman and infrared spectroscopy. The solid solution is complete, with the space group C2/m (monoclinic) being retained throughout. The unit-cell parameters decrease in size along all crystallographic directions as the amount of Ni increases. The β angle in the unit cell also decreases from 105.05(1)° (erythrite) to 104.90(1)° (annabergite). Crystals of annabergite and samples with a high Ni content are elongate along the a axis, and contrast with crystals of erythrite and Co-rich samples, which are elongate along c. In the Raman and infrared spectra of the synthetic samples, the band positions shift in accordance with the increase in bond strength associated with the decrease in the unit-cell parameters. Trends in positions of the antisymmetric arsenate stretching vibrations in the Raman spectra are sensitive to the site occupancy of metal ions in the structure. Changes in the crystal morphology, unit-cell parameters and vibrational spectra have been rationalized in terms of the site occupancy of Co and Ni in the structure. Substitution of Ni is directed to metal site 1 (C 2h site symmetry), whereas Co is directed to metal site 2 (C 2 site symmetry). Raman spectroscopy has proved to be useful for the determination of site occupancy of metal ions in solid solutions of minerals.

Well-mixed blends of poly(ethylene) and poly(styrene) have been synthesized using supercritical carbon dioxide as a solvent. The morphology of the blends has been conclusively characterized using differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), Raman microprobe microscopy, and C-13 solid-state cross-polarization magic angle spinning NMR (C-13 CPMAS NMR). DSC measurements demonstrate that poly(styrene) in the blends resides solely in the amorphous regions of the poly(ethylene) matrix; however, corroborative evidence from the SAXS experiments shows that poly(styrene) resides within the interlamellar spaces. The existence of nanometer-sized domains of poly(styrene) was shown within a blend of poly(styrene) and poly(ethylene) when formed in supercritical carbon dioxide using Raman microprobe microscopy and C-13 CPMAS NMR spectroscopy coupled with a spin diffusion model. This contrasts with blends formed at ambient pressure in the absence of solvent, in which domains of poly(styrene) in the micrometer size range are formed. This apparent improved miscibility of the two components was attributed to better penetration of the monomer prior to polymerization and increased swelling of the polymer substrate by the supercritical carbon dioxide solvent.

The Raman spectroscopic data in the range of 500–1800 cm−1 for two series of thirty homoleptic bis(phthalocyaninato) rare earth complexes M(Pc)2 and M[Pc(OC8H17)8]2 [M = Y, La–Lu except Pm; H2Pc = unsubstituted phthalocyanine, H2Pc(OC8H17)8 = 2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyanine] have been collected and comparatively studied using laser excitation sources emitting at 633 and 785 nm. Under both laser excitations, the marker Raman band of Pc2− and [Pc(OC8H17)8]2− in the Raman spectra of Ce(Pc)2 and Ce[Pc(OC8H17)8]2 appears as a strong scattering at 1498–1501 cm−1 with contributions from both pyrrole C C and aza C N stretches together with isoindole stretchings. This band has been found to upshift to 1502–1528 cm−1 in the Raman spectra of MIII(Pc)2 and MIII[Pc(OC8H17)8]2 as the marker Raman band of phthalocyanine monoanion radicals, Pc − or [Pc(OC8H17)8] −. With laser excitation at 633 nm, Raman vibrations derived from isoindole ring and aza stretchings in the range of 1300–1600 cm−1 for both series are selectively intensified. In contrast, when excited with laser radiation of 785 nm, the ring radial vibrations of isoindole moieties and dihedral plane deformations between 500 and 1000 cm−1 for M(Pc)2 and M[Pc(OC8H17)8]2 intensify to become the strongest scatterings. The present Raman results also reveal that the frequencies of Pc breathing, pyrrole stretching, isoindole stretchings, aza stretchings and coupling of pyrrole and aza stretchings depend on the rare earth ionic size, shifting to higher wavenumbers along with the lanthanide contraction due to the increased ring–ring interaction across the series. Moreover, under these laser excitations, in particular under 785 nm laser line, the Raman spectrum appearance, i.e., the pattern of relative intensities, also changes systematically depending on the rare earth ionic size.

In this study, radiation induced changes in a polymer gel dosimeter manufactured using 2-hydroxyethylacrylate (HEA) and N,N'-methylene-bisacrylamide (BIS) were investigated using magnetic resonance imaging (MRI) and FT-Raman spectroscopy. The variation in magnetic resonance relaxation time (T2) with absorbed dose was modelled assuming fast exchange of magnetization. Overall good agreement between the model and experimental data was obtained. However, comparison with FT-Raman data suggests that not all the protons attached to the polymer contribute to the relaxation process. Furthermore, for certain compositions improved agreement with experimental data was achieved when a lower fraction of polymer protons available for exchange with water was assumed in the low dose region. This indicates that the T2 value is influenced by the composition and topology of the formed polymer, which may vary with absorbed dose. The concept of percentage dose resolution (Dp delta, %) was introduced to enable optimization of gel compositions for use in relative dosimetry applications. This concept was applied to demonstrate the effects of varying the gelatine concentration, the total fraction of monomer/crosslinker (%T) and the relative fraction of crosslinker (%C) on gel performance in HEA gels as well as compare the performance of HEA and a standard polyacrylamide gel (PAG). The percentage dose resolution was improved for all HEA gels compared to the PAG dosimeter containing 3% acrylamide and 3% BIS. Increasing the total concentration of monomer was shown to have the largest single effect. In the range of doses of interest for clinical radiation therapy, Dp delta, % for the optimal HEA gel (4% HEA, 4% BIS) was lower than 2.3%, compared to 3.8% for the PAG dosimeter.

Raman spectroscopic data in the range of 500-1800 cm-1 for a series of 15 mixed \[tetrakis(4-chlorophenyl)porphyrinato](phthalocyaninato) double-decker complexes with tervalent rare earths MIII(TClPP)(Pc) (M = Y, La...Lu except Ce and Pm) and intermediate-valent cerium Ce(TClPP)(Pc) have been collected using laser excitation sources emitting at 632.8 and 785 nm. Comparison with the Raman spectra of corresponding bis phthalocyaninato) rare earths reveals that the Raman characteristics of mixed ring double-deckers are dominated by the phthalocyaninato-metal fragment M(Pc) and phthalocyanine exists as monoradical anion Pc•- in MIII(TClPP)(Pc) and dianion Pc2- in Ce(TClPP)(Pc), respectively. Under excitation at 632.8 nm that is in close resonance with the main Q absorption band of phthalocyanine ligand, typical Raman marker band of the monoanion radical Pc•- was observed at 1512-1519 cm-1 as a weak band resulting from the coupling of pyrrole C=C and aza C=N stretchings. For Ce(TClPP)(Pc), a strong band at 1492 cm-1 with contributions from both pyrrole C=C and aza C=N stretchings as well as the isoindole stretching was the marker Raman band of Pc2-. When excited with laser radiation of 785 nm, which is far away from the main Q absorption band of the phthalocyanine ligand, the marker Raman band of Pc•- in MIII(TClPP)(Pc) is observed at 1495-1514 cm-1 and of Pc2- in Ce(TClPP)(Pc) at 1511 cm-1 as a strong band.

Raman spectroscopic data in the range of 400–1800 cm −1 for a series of 15 mixed (octaethylporphyrinato)(naphthalocyaninato) double-decker complexes with tervalent rare earths M III (OEP)(2,3-Nc) (M=Y, La, …, Lu except Ce and Pm) and intermediate valent cerium Ce(OEP)(2,3-Nc) have been collected using laser excitation sources emitting at 632.8 and 785 nm. Comparison with the Raman spectra of the corresponding bis(naphthalocyaninato) rare earths reveals that the Raman characteristics of mixed ring double-deckers M(OEP)(2,3-Nc) are dominated by the metallonaphthalocyanine M(2,3-Nc) fragment. Under excitation at 632.8 nm, which is far away from the main Q absorption band of the naphthalocyanine ligand, the most intense Raman band appears at 1598 cm −1 for M III (OEP)(2,3-Nc) (M≠Ce), and is assigned to the naphthalene stretching. On the other hand, for Ce(OEP)(2,3-Nc), this vibration appears as a strongly enhanced peak at 1550 cm −1 together with a medium intense band at 1613 cm −1 . Typical Raman marker bands of the monoanion radical Nc − were observed at 1499–1512 cm −1 as a medium band and at 1521−1538 cm −1 as a band whose intensity increases along with the rare earth contraction, resulting from the coupling of pyrrole CC and aza CN stretchings and aza CN-only stretchings, respectively. For Ce(OEP)(2,3-Nc), a weak and broad band centered at 1507 cm −1 with contribution from both pyrrole CC and aza CN stretches together with isoindole stretches was the marker Raman band of Nc 2− . When excited with laser radiation of 785 nm which is in close resonance with the main Q absorption band of naphthalocyanine ligand, the ring radial vibrations of the isoindole moieties at ca. 680 and 732 cm −1 in the Raman spectra of both M III (OEP)(2,3-Nc) and Ce(OEP)(2,3-Nc) are selectively intensified and appear as the most intense vibrations. The marker Raman bands of Nc − in M III (OEP)(2,3-Nc) and Nc 2− in Ce(OEP)(2,3-Nc) are observed in similar regions to those found for excitation at 632.8 nm. The scatterings with contribution from the Nc breathings, ring radial vibration, naphthalene stretchings, benzoisoindole stretchings, aza group stretchings, and the coupling of pyrrole CC and aza CN stretchings in M III (OEP)(2,3-Nc) all show dependence on the rare earth radius, shifting to higher energy along with the rare earth contraction and showing the rare earth ionic size effect on the Raman characteristics of naphthalocyanine in the mixed ring double-decker compounds.

The grafting of polystyrene (PS) onto a predominantly polypropylene (PP) substrate has been followed by Raman and infrared microspectroscopic mapping. For exactly the same 50 μm × 50 μm section of polymer surface, Raman spectra were obtained at 1 μm intervals for the substrate, the surface after plasma treatment, and the surface after PS grafting. Maps of the substrate were constructed, indicating the crystallinity variation across the surface and also the distribution of the minor component ethylene-propylene rubber (EPR). After plasma treatment, the crystallinity was found to decrease slightly. Infrared microspectroscopic maps of a larger plasma-treated surface were also obtained with the technique of attenuated total reflection. The spatial resolution of these maps was 50 μm, and they showed the distribution of the hydroxy groups introduced onto the surface by the plasma treatment. PS grafting was found to be heterogeneous. Increased concentrations of grafted PS showed some correlation with positions on the surface which had higher EPR after plasma treatment.