Process engineering approach to large-volume methacrylate monolith synthesis for plasmid purification

The construction of large?volume methacrylate monolithic columns for preparative-scale plasmid purification is obstructed by the enormous release of exotherms, thus introducing structural heterogeneity in the monolith pore system. A remarkable radial temperature gradient develops along the monolith thickness, reaching a terminal temperature that supersedes the maximum temperature required for the preparation of a structurally homogeneous monolith. A novel heat expulsion technique is employed to overcome the heat build-up during the synthesis process. The enormous heat build-up is perceived to encompass the heat associated with initiator decomposition and the heat released from free radical-monomer and monomer-monomer interactions. The heat resulting from the initiator decomposition was expelled along with some gaseous fumes before commencing polymerisation in a gradual addition fashion. Characteristics of a 50 mL monolith synthesized using this technique showed an improved uniformity in the pore structure radially along the length on the monolith. Chromatographic characterization of this adsorbent displayed a persistent binding capacity of 14.5 mg pDNA/mL of the adsorbent. The adsorbent was able to fractionate a clarified bacteria lysate in only 3 min (after loading) into RNA, protein and pDNA respectively. The pDNA fraction obtained was analyzed to be a homogeneous supercoiled pDNA.

Synthesis of novel interlocked architectures in solution and solid phase

Mechanically interlocked molecules, such as catenanes and rotaxanes, are fascinating due to their unique sensing and catalytic properties and their potential to act as molecular motors or switches. Traditionally their synthesis has been laborious and expensive, however this research project endeavoured to overcome this challenge by exploring novel ways of preparing mechanically interlocked molecules both in solution and on surfaces. A series of disulfide-linked macrocycles, [2]catenanes and [2]rotaxanes were synthesised in solution using reversible dynamic covalent chemistry. Subsequently, the interlocked architectures were adapted into solid-tethered systems via attachment to swelling polystyrene resins.

Bayesian networks for information synthesis in complex systems

This thesis introduces a method of applying Bayesian Networks to combine information from a range of data sources for effective decision support systems. It develops a set of techniques in development, validation, visualisation, and application of Complex Systems models, with a working demonstration in an Australian airport environment. The methods presented here have provided a modelling approach that produces highly flexible, informative and applicable interpretations of a system's behaviour under uncertain conditions. These end-to-end techniques are applied to the development of model based dashboards to support operators and decision makers in the multi-stakeholder airport environment. They provide highly flexible and informative interpretations and confidence in these interpretations of a system's behaviour under uncertain conditions.

The synthesis, characterization, X-ray structure and magnetism of dinuclear-based bis[μ-(1,1,3,3-tetracyano-2-ethoxypropenido-κ2N,N′) (1,1,3,3-tetracyano-2-ethoxypropenido-κN)(2,2′-bipyridine)copper(II)] organized in alternating chains via semi-coordinating Cu–N distances

The monoanionic ligand 1,1,3,3 tetracyano-2 ethoxypropenide (tcnoet) is reported with its Cu(II)–bpy complex of formula [Cu2(µ-tcnoet)2(tcnoet)2(bpy)2]. The structure has been determined using X-ray diffraction and features an alternating chain with bridging tcnoet ligands. One ligand acts as a bidentate, dinucleating ligand with one short Cu–N and one medium Cu–N bond, whereas the other tcnoet is largely monodentate, albeit with a very weak interdimer Cu–N bond. Despite the arrangement in dinuclear units, further arranged into linear chains through the non-bridging tcnoet ligand, the compound shows no significant magnetic exchange, as deduced from magnetic susceptibility down to 4 K. Ligand-field, IR and EPR spectra in the solid state and in frozen solution are reported and are consistent with the overall structure.

Design and synthesis of a screening library using the natural product scaffold 3-chloro-4-hydroxyphenylacetic acid

The fungal metabolite 3-chloro-4-hydroxyphenylacetic acid (1) was utilized in the generation of a unique drug-like screening library using parallel solution-phase synthesis. A 20-membered amide library (3–22) was generated by first converting 1 to methyl (3-chloro-4-hydroxyphenyl)acetate (2), then reacting this scaffold with a diverse series of primary amines via a solvent-free aminolysis procedure. The structures of the synthetic analogues (3–22) were elucidated by spectroscopic data analysis. The structures of compounds 8, 12, and 22 were confirmed by single X-ray crystallographic analysis. All compounds were evaluated for cytotoxicity against a human prostate cancer cell line (LNCaP) and for antiparasitic activity toward Trypanosoma brucei brucei and Plasmodium falciparum and showed no significant activity at 10 μM. The library was also tested for effects on the lipid content of LNCaP and PC-3 prostate cancer cells, and it was demonstrated that the fluorobenzyl analogues (12–14) significantly reduced cellular phospholipid and neutral lipid levels.

Synthesis of organoclays: A critical review and some unresolved issues

The synthesis of organoclays (OC) by intercalation of quaternary ammonium cation (QAC) into expanding clay minerals, notably montmorillonite (Mt), has attracted a great deal of attention during the past two decades. The OC have also found applications in the manufacture of clay polymer nanocomposites (CPN) and environmental remediation. Despite the wealth of information that exists on the formation and properties of OC, some problems remain to be resolved. The present contribution is an attempt at clarifying two outstanding issues, based on the literature and experimental data obtained by the authors over the past years. The first issue concerns the relationship between the cation exchange capacity (CEC) of the Mt and the basal spacing of the OC which, in turn, is dependent on the concentration and the nature of the added QAC. At a concentration less than 1 CEC, organo-Mt (OMt) formed using the QAC with a short alkyl chain length with nc < 16 (e.g., dodecyl trimethylammonium) gives basal spacings of 1.4–1.6 nm that are essentially independent of the CEC. However, for long-chain QAC with nc ≥ 16 (e.g., hexadecyl trimethylammonium), the basal spacing varies with the QAC concentration. For Mt with a CEC of 80–90 meq/100 g, the basal spacing of the OC increases gradually with the CEC and shows a sudden (stepwise) increase to 3.2–3.8 nm at a QAC concentration of 1.5 CEC and to 3.5–4.0 nm at a concentration of 2.0 CEC. The second issue pertains to the “locking” effect in QAC- and silane-modified pillared interlayered clays (PILC) and Mt. For silylated Mt, the “locking” effect results from the covalent bonding of silane to two adjacent layers within a single clay mineral particle. The same mechanism can operate in silane-grafted PILC but in this case, the “locking” effect may primarily be ascribed to the pillaring of adjacent basal surfaces by metal hydr(oxides).

Service Interface Synthesis in Business Networks

Mismatches between services needing to interoperate have been addressed through the adaptation of structural and behavioural interfaces of services, which in practice incur long lead time through manual, coding effort. We propose a framework, complementary to con- ventional service adaptation, to synthesise service interfaces in the open setting of business networks, allowing consumers to introspect service interfaces and formulate service invocations. The framework also allows evolved service requests, as new features of service capabilities are discov- ered, through interactions with other, similar services. Finally the frame- work fosters reuse of adaptation efforts through normalisation of struc- tural and behavioural interfaces of similar services. This paper provides a first exposition of the service interface synthesis framework, describing patterns containing novel requirements for unilateral service adaptation and detailing the interface synthesis technique. Complex examples of ser- vices drawn from commercial logistic systems are then used to validate the synthesis technique and identify open challenges and future research directions.

Visible light photocatalytic synthesis of fine organic chemicals with new photocatalysts

This project was a step forward in developing new recyclable photocatalysts for chemical reactions. These new photocatalysts can facilitate reactions by using visible light under moderate reaction conditions which is suitable for a sustainable, green and eco-friendly modern chemical industry. The outcome of the study greatly extended our understanding in metal nanoparticle photocatalysis, which reveals new photocatalytic mechanisms for the controlled transformation of chemical reactions. The prospect of sunlight irradiation driving chemical reactions may provide opportunity for the organic synthesis via a more controlled, simplified, and greener process in the future.

Synthesis and applications of carbon nanomaterials for energy generation and storage

The world is facing an energy crisis due to exponential population growth and limited availability of fossil fuels. Carbon, one of the most abundant materials found on earth, and its allotrope forms have been proposed in this project for novel energy generation and storage devices. This studied investigated the synthesis and properties of these carbon nanomaterials for applications in organic solar cells and supercapacitors.

Synthesis, characterization and applications of graphene oxide-polymer nanocomposites

Graphene has emerged as one of the most exciting materials of the 21st century due to its unique properties which have demonstrated great potential for applications in energy storage, flexible electronics and multifunctional composites. This thesis has established a new technique for investigating the structure-property relationship of graphene-polymer nanocomposites at micro and nanoscales. The outcomes can help gain a fundamental understanding of the toughening mechanism in these novel nanocomposites and benefit the development of broad graphene based materials and devices.

Phase-selective hydrothermal synthesis of Cu2ZnSnS4nanocrystals: The effect of the sulphur precursor

High quality Cu2ZnSnS4 (CZTS) films with uniform thickness and smooth surface were prepared using nanocrystals synthesized by a one-step hydrothermal method. It is found that the nature of the sulphur precursor used in the hydrothermal reaction influences both the compositional purity and the crystal structure of the synthesized hydrothermal product significantly. The CZTS material consisting of both wurtzite and kesterite crystal structures was obtained when using an organic sulfur precursor such as thioacetamide and thiourea in the precursor solution of the hydrothermal reaction while the pure kesterite phase CZTS nanocrystals were made when Na2S was employed as the sulphur precursor. CZTS thin films deposited on a Mo–soda lime glass substrate with uniform thickness (1.7 μm) were made by a simple doctor-blading method. The investigation of the effect of thermal treatment on the film has indicated that the wurtzite CZTS material was completely transformed to the kesterite phase when the material was annealed at 550 °C. Large grains (around 2 μm in size) were found on the surface of the CZTS film which was annealed at 600 °C. The evaluation of the photoresponse of the CZTS thin films has showed that a higher and very stable photocurrent was generated by the film annealed at 600 °C compared to the film annealed at 550 °C.

One-step synthesis of high quality kesterite Cu2ZnSnS4nanocrystals: A hydrothermal approach

The present work demonstrates a systematic approach for the synthesis of pure kesterite-phase Cu2ZnSnS4 (CZTS) nanocrystals with a uniform size distribution by a one-step, thioglycolic acid (TGA)-assisted hydrothermal route. The formation mechanism and the role of TGA in the formation of CZTS compound were thoroughly studied. It has been found that TGA interacted with Cu2+ to form Cu+ at the initial reaction stage and controlled the crystal-growth of CZTS nanocrystals during the hydrothermal reaction. The consequence of the reduction of Cu2+ to Cu+ led to the formation Cu2−xS nuclei, which acted as the crystal framework for the formation of CZTS compound. CZTS was formed by the diffusion of Zn2+ and Sn4+ cations to the lattice of Cu2−xS during the hydrothermal reaction. The as-synthesized CZTS nanocrystals exhibited strong light absorption over the range of wavelength beyond 1000 nm. The band gap of the material was determined to be 1.51 eV, which is optimal for application in photoelectric energy conversion device.

Polyacrylic Acid Assisted Synthesis of Cu2ZnSnS4 by Hydrothermal Method

Pure phase Cu2ZnSnS4 (CZTS) nanoparticles were successfully synthesized via polyacrylic acid (PAA) assisted one-pot hydrothermal route. The morphology, crystal structure, composition and optical properties as well as the photoactivity of the as-synthesized CZTS nanoparticles were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectrometer, UV-visible absorption spectroscopy and photoelectrochemical measurement. The influence of various synthetic conditions, such as the reaction temperature, reaction duration and the amount of PAA in the precursor solution on the formation of CZTS compound was systematically investigated. The results have shown that the crystal phase, morphology and particle size of CZTS can be tailored by controlling the reaction conditions. The formation mechanism of CZTS in the hydrothermal reaction has been proposed based on the investigation of time-dependent phase evolution of CZTS which showed that metal sulfides (e.g., Cu2S, SnS2 and ZnS) were formed firstly during the hydrothermal reaction before forming CZTS compound through nucleation. The band gap of the as-synthesized CZTS nanoparticles is 1.49 eV. The thin film electrode based on the synthesized CZTS nanoparticles in a three-electrode photoelectrochemical cell generated pronounced photocurrent under illumination provided by a red light-emitting diode (LED, 627 nm), indicating the photoactivity of the semiconductor material.

Transdisciplinary synthesis for ecosystem science, policy and management: The Australian experience

Mitigating the environmental effects of global population growth, climatic change and increasing socio-ecological complexity is a daunting challenge. To tackle this requires synthesis: the integration of disparate information to generate novel insights from heterogeneous, complex situations where there are diverse perspectives. Since 1995, a structured approach to inter-, multi- and trans-disciplinary1 collaboration around big science questions has been supported through synthesis centres around the world. These centres are finding an expanding role due to ever-accumulating data and the need for more and better opportunities to develop transdisciplinary and holistic approaches to solve real-world problems. The Australian Centre for Ecological Analysis and Synthesis (ACEAS ) has been the pioneering ecosystem science synthesis centre in the Southern Hemisphere. Such centres provide analysis and synthesis opportunities for time-pressed scientists, policy-makers and managers. They provide the scientific and organisational environs for virtual and face-to-face engagement, impetus for integration, data and methodological support, and innovative ways to deliver synthesis products. We detail the contribution, role and value of synthesis using ACEAS to exemplify the capacity for synthesis centres to facilitate trans-organisational, transdisciplinary synthesis. We compare ACEAS to other international synthesis centres, and describe how it facilitated project teams and its objective of linking natural resource science to policy to management. Scientists and managers were brought together to actively collaborate in multi-institutional, cross-sectoral and transdisciplinary research on contemporary ecological problems. The teams analysed, integrated and synthesised existing data to co-develop solution-oriented publications and management recommendations that might otherwise not have been produced. We identify key outcomes of some ACEAS working groups which used synthesis to tackle important ecosystem challenges. We also examine the barriers and enablers to synthesis, so that risks can be minimised and successful outcomes maximised. We argue that synthesis centres have a crucial role in developing, communicating and using synthetic transdisciplinary research.