Energy efficiency in nanoscale synthesis using nanosecond plasmas

We report a nanoscale synthesis technique using nanosecond-duration plasma discharges. Voltage pulses 12.5 kV in amplitude and 40 ns in duration were applied repetitively at 30 kHz across molybdenum electrodes in open ambient air, generating a nanosecond spark discharge that synthesized well-defined MoO 3 nanoscale architectures (i.e. flakes, dots, walls, porous networks) upon polyamide and copper substrates. No nitrides were formed. The energy cost was as low as 75 eV per atom incorporated into a nanostructure, suggesting a dramatic reduction compared to other techniques using atmospheric pressure plasmas. These findings show that highly efficient synthesis at atmospheric pressure without catalysts or external substrate heating can be achieved in a simple fashion using nanosecond discharges.

Discussion on full-scale internal pressure measurements

The wind loading on most structural elements is made up of both an external and internal pressure. Internal pressures are also important for the design of naturally ventilated buildings. The internal pressure is the interaction between the external pressure propagating through the building envelope and any internal plant causing building pressurization. Although the external pressure field can be well defined through a series of wind tunnel tests, modeling complexities makes accurate prediction of the internal pressure difficult. For commercial testing for the determination of design cladding pressures, an internal pressure coefficient is generally assumed from wind loading standards. Several theories regarding the propagation of internal pressures through single and multiple dominant openings have been proposed for small and large flexible buildings (Harris (1990), Holmes, (1979), Liu & Saathoff (1981 ), Vickery (1986, 1994), Vickery & Bloxham (1992), Vickery & Georgiou (1991))...

Synthesis, characterization and comparative OFET behaviour of indenofluorene-bithiophene and terthiophene alternating copolymers

The synthesis of alternating copolymers of tetraalkylindenofluorene with bithiophene and terthiophene using Suzuki polycondensation route is reported. We report on the optical and electrochemical properties of these copolymers. AFM analysis of the microscopic morphology of thin deposits showed that the copolymer with terthiophene units produced the more ordered films, with well-defined fibrillar structures, resulting from highly-regular dense packing due to strong π-π interchain interactions, in contrast to the amorphous bithiophene copolymer. Upon testing these materials in FETs the terthienyl copolymers displayed the higher charge mobilities among the studied compounds, with values of over 10-4 cm2 V-1 s-1 being obtained.

Solid-state assemblies and optical properties of conjugated oligomers combining fluorene and thiophene units

Two conjugated oligomers, representing elementary segments of fluorene-thiophene copolymers, are compared in terms of the microscopic morphology and the optical properties of thin deposits. The atomic force microscopy morphological data and the solid-state absorption and emission spectra are interpreted in terms of the assembly of the conjugated molecules. The compound with a terthiophene central unit and fluorene end-groups shows well-defined monolayer-by-monolayer assembly into micrometer-long stripe-like structures, with a crystalline herringbone-type organization within the monolayers. Polarized confocal microscopy indicates a strong orientation of the crystalline domains within the stripes. In contrast, the compound with a terfluorene central unit and thiophene end groups forms no textured aggregates and the optical spectra in the solid-state are very similar to those recorded in solution, suggesting that the molecules interact only weakly in the solid. The difference in behaviour between the two compounds most probably originates from their different capability to form densely-packed assemblies of interacting π-systems.

Nonvolatile multilevel data storage memory device from controlled ambipolar charge trapping mechanism

The capability of storing multi-bit information is one of the most important challenges in memory technologies. An ambipolar polymer which intrinsically has the ability to transport electrons and holes as a semiconducting layer provides an opportunity for the charge trapping layer to trap both electrons and holes efficiently. Here, we achieved large memory window and distinct multilevel data storage by utilizing the phenomena of ambipolar charge trapping mechanism. As fabricated flexible memory devices display five well-defined data levels with good endurance and retention properties showing potential application in printed electronics.

Real-time decision making by driverless city vehicles : a discrete event driven approach

This thesis addresses the topic of real-time decision making by driverless (autonomous) city vehicles, i.e. their ability to make appropriate driving decisions in non-simplified urban traffic conditions. After addressing the state of research, and explaining the research question, the thesis presents solutions for the subcomponents which are relevant for decision making with respect to information input (World Model), information output (Driving Maneuvers), and the real-time decision making process. TheWorld Model is a software component developed to fulfill the purpose of collecting information from perception and communication subsystems, maintaining an up-to-date view of the vehicle’s environment, and providing the required input information to the Real-Time Decision Making subsystem in a well-defined, and structured way. The real-time decision making process consists of two consecutive stages. While the first decision making stage uses a Petri net to model the safetycritical selection of feasible driving maneuvers, the second stage uses Multiple Criteria Decision Making (MCDM) methods to select the most appropriate driving maneuver, focusing on fulfilling objectives related to efficiency and comfort. The complex task of autonomous driving is subdivided into subtasks, called driving maneuvers, which represent the output (i.e. decision alternatives) of the real-time decision making process. Driving maneuvers are considered as implementations of closed-loop control algorithms, each capable of maneuvering the autonomous vehicle in a specific traffic situation. Experimental tests in both a 3D simulation and real-world experiments attest that the developed approach is suitable to deal with the complexity of real-world urban traffic situations.

Exploitation of the menshutkin reaction for the controlled assembly of halogen bonded architectures incorporating 1,2-diiodotetrafluorobenzene and 1,3,5-Triiodotrifluorobenzene

1,4-Diazabicyclo[2.2.2]octane (DABCO) forms well-defined co-crystals with 1,2-diiodotetrafluorobenzene (1,2-DITFB), [(1,2-DITFB)2DABCO], and 1,3,5-triiodotrifluorobenzene, [(1,3,5-TITFB)2DABCO]. Both systems exhibited lower-than-expected supramolecular connectivity, which inspired a search for polymorphs in alternative crystallization solvents. In dichloromethane solution, the Menshutkin reaction was found to occur, generating chloride anions and quaternary ammonium cations through the reaction between the solvent and DABCO. The controlled in situ production of chloride ions facilitated the crystallization of new halogen bonded networks, DABCO–CH2Cl[(1,2-DITFB)Cl] (zigzag X-bonded chains) and (DABCO–CH2Cl)3[(1,3,5-TITFB)2Cl3]·CHCl3 (2D pseudo-trigonal X-bonded nets displaying Borremean entanglement), propagating with charge-assisted C–I···Cl– halogen bonds. The method was found to be versatile, and substitution of DABCO with triethylamine (TEA) gave (TEA-CH2Cl)3[(1,2-DITFB)Cl3]·4(H2O) (mixed halogen bond hydrogen bond network with 2D supramolecular connectivity) and TEA-CH2Cl[(1,3,5-TITFB)Cl] (tightly packed planar trigonal nets). The co-crystals were typically produced in high yield and purity with relatively predictable supramolecular topology, particularly with respect to the connectivity of the iodobenzene molecules. The potential to use this synthetic methodology for crystal engineering of halogen bonded architectures is demonstrated and discussed.

F9 fimbriae of uropathogenic Escherichia coli are expressed at low temperature and recognise Galβ1-3GlcNAc-containing glycans

Uropathogenic Escherichia coli (UPEC) is the leading causative agent of urinary tract infections (UTI) in the developed world. Among the major virulence factors of UPEC, surface expressed adhesins mediate attachment and tissue tropism. UPEC strains typically possess a range of adhesins, with type 1 fimbriae and P fimbriae of the chaperone-usher class the best characterised. We previously identified and characterised F9 as a new chaperone-usher fimbrial type that mediates biofilm formation. However, the regulation and specific role of F9 fimbriae remained to be determined in the context of wild-type clinical UPEC strains. In this study we have assessed the distribution and genetic context of the f9 operon among diverse E. coli lineages and pathotypes and demonstrated that f9 genes are significantly more conserved in a UPEC strain collection in comparison to the well-defined E. coli reference (ECOR) collection. In the prototypic UPEC strain CFT073, the global regulator protein H-NS was identified as a transcriptional repressor of f9 gene expression at 37°C through its ability to bind directly to the f9 promoter region. F9 fimbriae expression was demonstrated at 20°C, representing the first evidence of functional F9 fimbriae expression by wild-type E. coli. Finally, glycan array analysis demonstrated that F9 fimbriae recognise and bind to terminal Galβ1-3GlcNAc structures.

Innate transcriptional networks activated in bladder in response to uropathogenic Escherichia coli drive diverse biological pathways and rapid synthesis of IL-10 for defense against bacterial urinary tract infection

Early transcriptional activation events that occur in bladder immediately following bacterial urinary tract infection (UTI) are not well defined. In this study, we describe the whole bladder transcriptome of uropathogenic Escherichia coli (UPEC) cystitis in mice using genome-wide expression profiling to define the transcriptome of innate immune activation stemming from UPEC colonization of the bladder. Bladder RNA from female C57BL/6 mice, analyzed using 1.0 ST-Affymetrix microarrays, revealed extensive activation of diverse sets of innate immune response genes, including those that encode multiple IL-family members, receptors, metabolic regulators, MAPK activators, and lymphocyte signaling molecules. These were among 1564 genes differentially regulated at 2 h postinfection, highlighting a rapid and broad innate immune response to bladder colonization. Integrative systems-level analyses using InnateDB (http://www.innatedb.com) bioinformatics and ingenuity pathway analysis identified multiple distinct biological pathways in the bladder transcriptome with extensive involvement of lymphocyte signaling, cell cycle alterations, cytoskeletal, and metabolic changes. A key regulator of IL activity identified in the transcriptome was IL-10, which was analyzed functionally to reveal marked exacerbation of cystitis in IL-10–deficient mice. Studies of clinical UTI revealed significantly elevated urinary IL-10 in patients with UPEC cystitis, indicating a role for IL-10 in the innate response to human UTI. The whole bladder transcriptome presented in this work provides new insight into the diversity of innate factors that determine UTI on a genome-wide scale and will be valuable for further data mining. Identification of protective roles for other elements in the transcriptome will provide critical new insight into the complex cascade of events that underpin UTI.

Characterization of two homologous disulfide bond systems involved in virulence factor Biogenesis in Uropathogenic Escherichia coli CFT073

Disulfide bond (DSB) formation is catalyzed by disulfide bond proteins and is critical for the proper folding and functioning of secreted and membrane-associated bacterial proteins. Uropathogenic Escherichia coli (UPEC) strains possess two paralogous disulfide bond systems: the well-characterized DsbAB system and the recently described DsbLI system. In the DsbAB system, the highly oxidizing DsbA protein introduces disulfide bonds into unfolded polypeptides by donating its redox-active disulfide and is in turn reoxidized by DsbB. DsbA has broad substrate specificity and reacts readily with reduced unfolded proteins entering the periplasm. The DsbLI system also comprises a functional redox pair; however, DsbL catalyzes the specific oxidative folding of the large periplasmic enzyme arylsulfate sulfotransferase (ASST). In this study, we characterized the DsbLI system of the prototypic UPEC strain CFT073 and examined the contributions of the DsbAB and DsbLI systems to the production of functional flagella as well as type 1 and P fimbriae. The DsbLI system was able to catalyze disulfide bond formation in several well-defined DsbA targets when provided in trans on a multicopy plasmid. In a mouse urinary tract infection model, the isogenic dsbAB deletion mutant of CFT073 was severely attenuated, while deletion of dsbLI or assT did not affect colonization.

The relationship between ambient ultraviolet radiation (UVR) and objectively measured personal UVR exposure dose is modified by season and latitude

Despite the widespread use of ambient ultraviolet radiation (UVR) as a proxy measure of personal exposure to UVR, the relationship between the two is not well-defined. This paper examines the effects of season and latitude on the relationship between ambient UVR and personal UVR exposure. We used data from the AusD Study, a multi-centre cross-sectional study among Australian adults (18-75 years), where personal UVR exposure was objectively measured using polysulphone dosimeters. Data were analysed for 991 participants from 4 Australian cities of different latitude: Townsville (19.3 °S), Brisbane (27.5 °S), Canberra (35.3 °S) and Hobart (42.8 °S). Daily personal UVR exposure varied from 0.01 to 21 Standard Erythemal Doses (median=1.1, IQR: 0.5–2.1), on average accounting for 5% of the total available ambient dose. There was an overall positive correlation between ambient UVR and personal UVR exposure (r=0.23, p<0.001). However, the correlations varied according to season and study location: from strong correlations in winter (r=0.50) and at high latitudes (Hobart, r=0.50; Canberra, r=0.39), to null or even slightly negative correlations, in summer (r=0.01) and at low latitudes (Townsville, r=-0.06; Brisbane, r=-0.16). Multiple regression models showed significant effect modification by season and location. Personal exposure fraction of total available ambient dose was highest in winter (7%) and amongst Hobart participants (7%) and lowest in summer (1%) and in Townsville (4%). These results suggest season and latitude modify the relationship between ambient UVR and personal UVR exposure. Ambient UVR may not be a good indicator for personal exposure dose under some circumstances.

Design, manufacturing and maintenance of sugar milling equipment : observations from the 2008 ISSCT Engineering Workshop

An International Society of Sugar Cane Technologists (ISSCT) Engineering Workshop was held in Piracicaba, Brazil from 30 June to 4 July 2008. The theme of the workshop was Design, manufacturing and maintenance of sugar mill equipment. The workshop consisted of a series of technical sessions and site visits. The Brazilian sugar industry is growing rapidly. The growth has occurred as the result of the sugar industry’s position as a key provider of renewable energy in the form of ethanol and, more recently, electricity. The increased focus on electricity is seeing investment in high pressure (100 bar) boilers, cane cleaning plants that allow an increased biomass supply from trash and digesters that produce biogas from dunder. It is clear that the Brazilian sugar industry has a well defined place in the country’s future. The ISSCT workshop provided a good opportunity to gain information from equipment suppliers and discuss new technology that may have application in Australia. The new technologies of interest included IMCO sintered carbide shredder hammer tips, Fives Cail MillMax mills, planetary mill gearboxes, Bosch Projects chainless diffusers, Fives Cail Zuka centrifugals and Vaperma Siftek membrane systems.

Evaluation of the potential impact of the global economic crisis on HIV epidemics in Southeast Asia

Economic conditions around the world are likely to deteriorate in the short to medium term. The potential impact of this crisis on the spread of HIV is not clear. Government revenues and aid flows from international donors may face constraints, possibly leading to reductions in funding for HIV programs. Economic conditions (leading to increases in unemployment, for example) may also have an indirect impact on HIV epidemics by affecting the behaviour of individual people. Some behavioural changes may influence the rate of HIV transmission. This report presents findings from a study that investigates the potential impact of the economic crisis on HIV epidemics through the use of mathematical modelling. The potential epidemiological impacts of changes in the economy are explored for two distinctly characterised HIV epidemics: (i) a well-defined, established, and generalised HIV epidemic (specifically Cambodia, where incidence is declining); (ii) an HIV epidemic in its early expansion phase (specifically Papua New Guinea, where incidence has not yet peaked). Country-specific data are used for both settings and the models calibrated to accurately reflect the unique HIV epidemics in each population in terms of both incidence and prevalence. Models calibrated to describe the past and present epidemics are then used to forecast epidemic trajectories over the next few years under assumptions that behavioural or program conditions may change due to economic conditions. It should be noted that there are very limited solid data on how HIV/AIDS program funds may decrease or how social determinants related to HIV risk may change due to the economic crisis. Potential changes in key relevant factors were explored, along with sensitivity ranges around these assumptions, based on extensive discussions with in-country and international experts and stakeholders. As with all mathematical models, assumptions should be reviewed critically and results interpreted cautiously.

Understanding causal relationships between the built and social environment, health and associated behaviours and risk factors

Introduction: Built environment interventions designed to reduce non-communicable diseases and health inequity, complement urban planning agendas focused on creating more ‘liveable’, compact, pedestrian-friendly, less automobile dependent and more socially inclusive cities.However, what constitutes a ‘liveable’ community is not well defined. Moreover, there appears to be a gap between the concept and delivery of ‘liveable’ communities. The recently funded NHMRC Centre of Research Excellence (CRE) in Healthy Liveable Communities established in early 2014, has defined ‘liveability’ from a social determinants of health perspective. Using purpose-designed multilevel longitudinal data sets, it addresses five themes that address key evidence-base gaps for building healthy and liveable communities. The CRE in Healthy Liveable Communities seeks to generate and exchange new knowledge about: 1) measurement of policy-relevant built environment features associated with leading non-communicable disease risk factors (physical activity, obesity) and health outcomes (cardiovascular disease, diabetes) and mental health; 2) causal relationships and thresholds for built environment interventions using data from longitudinal studies and natural experiments; 3) thresholds for built environment interventions; 4) economic benefits of built environment interventions designed to influence health and wellbeing outcomes; and 5) factors, tools, and interventions that facilitate the translation of research into policy and practice. This evidence is critical to inform future policy and practice in health, land use, and transport planning. Moreover, to ensure policy-relevance and facilitate research translation, the CRE in Healthy Liveable Communities builds upon ongoing, and has established new, multi-sector collaborations with national and state policy-makers and practitioners. The symposium will commence with a brief introduction to embed the research within an Australian health and urban planning context, as well as providing an overall outline of the CRE in Healthy Liveable Communities, its structure and team. Next, an overview of the five research themes will be presented. Following these presentations, the Discussant will consider the implications of the research and opportunities for translation and knowledge exchange. Theme 2 will establish whether and to what extent the neighbourhood environment (built and social) is causally related to physical and mental health and associated behaviours and risk factors. In particular, research conducted as part of this theme will use data from large-scale, longitudinal-multilevel studies (HABITAT, RESIDE, AusDiab) to examine relationships that meet causality criteria via statistical methods such as longitudinal mixed-effect and fixed-effect models, multilevel and structural equation models; analyse data on residential preferences to investigate confounding due to neighbourhood self-selection and to use measurement and analysis tools such as propensity score matching and ‘within-person’ change modelling to address confounding; analyse data about individual-level factors that might confound, mediate or modify relationships between the neighbourhood environment and health and well-being (e.g., psychosocial factors, knowledge, perceptions, attitudes, functional status), and; analyse data on both objective neighbourhood characteristics and residents’ perceptions of these objective features to more accurately assess the relative contribution of objective and perceptual factors to outcomes such as health and well-being, physical activity, active transport, obesity, and sedentary behaviour. At the completion of the Theme 2, we will have demonstrated and applied statistical methods appropriate for determining causality and generated evidence about causal relationships between the neighbourhood environment, health, and related outcomes. This will provide planners and policy makers with a more robust (valid and reliable) basis on which to design healthy communities.

Fabrication of optochemical and electrochemical sensors using thin films of porphyrin and phthalocyanine derivatives

This paper describes the fabrication of thin films of porphyrin and metallophthalocyanine derivatives on different substrates for the optochemical detection of HCl gas and electrochemical determination of L-cysteine (CySH). Solid state gas sensor for HCl gas was fabricated by coating meso-substituted porphyrin derivatives on glass slide and examined optochemical sensing of HCl gas. The concentration of gaseous HCl was monitored from the changes in the absorbance of Soret band. Among the different porphyrin derivatives, meso- tetramesitylporphyrin (MTMP) coated film showed excellent sensitivity towards HCl and achieved a detection limit of 0.03ppm HCl. Further, we have studied the self-assembly of 1,8,15,22-tetraaminometallophthalocyanine (4α-MTAPc; M = Co and Ni) from DMF on GC electrode. The CVs for the self-assembled monolayers (SAMs) of 4α-CoIITAPc and 4α-NiIITAPc show two pairs of well-defined redox couple corresponding to metal and ring. Using the 4α-CoIITAPc SAM modified electrode, sensitive and selective detection of L-cysteine was demonstrated. Further, the SAM modified electrode also successfully separates the oxidation potentials of AA and CySH with a peak separation of 320mV.