Discovery of a lipid synthesising organ in the auditory system of an insect

Weta possess typical Ensifera ears. Each ear comprises three functional parts: two equally sized tympanal membranes, an underlying system of modified tracheal chambers, and the auditory sensory organ, the crista acustica. This organ sits within an enclosed fluid-filled channel-previously presumed to be hemolymph. The role this channel plays in insect hearing is unknown. We discovered that the fluid within the channel is not actually hemolymph, but a medium composed principally of lipid from a new class. Three-dimensional imaging of this lipid channel revealed a previously undescribed tissue structure within the channel, which we refer to as the olivarius organ. Investigations into the function of the olivarius reveal de novo lipid synthesis indicating that it is producing these lipids in situ from acetate. The auditory role of this lipid channel was investigated using Laser Doppler vibrometry of the tympanal membrane, which shows that the displacement of the membrane is significantly increased when the lipid is removed from the auditory system. Neural sensitivity of the system, however, decreased upon removal of the lipid-a surprising result considering that in a typical auditory system both the mechanical and auditory sensitivity are positively correlated. These two results coupled with 3D modelling of the auditory system lead us to hypothesize a model for weta audition, relying strongly on the presence of the lipid channel. This is the first instance of lipids being associated with an auditory system outside of the Odentocete cetaceans, demonstrating convergence for the use of lipids in hearing.

The presence of ultrasonic harmonics in the calls of the rifleman (Acanthisitta chloris)

Ultrasonic vocalisations (frequencies > 20 kHz) have been extensively studied in the context of echolocation by bats and other mammals (Sales & Pye 1974; Wilson & Hare 2004). Ultrasonic calls have also been recorded from birds, including the blue-throated hummingbird ( Lampornis clemenciae ) (Pytte et al. 2004), where it was first thought that individuals made use of high pitch calls to avoid masking by background noise in a visually obscured environment. Similarly, city-dwelling great tits ( Parus major ) use song with a higher minimum frequency (although not ultrasonic) compared to woodland birds to communicate with conspecifics to avoid the predominantly low-frequency background noise in the city (Slabbekorn & Peet 2003). The theory that birds use ultrasound to avoid noise masking was discarded when it was discovered that there was no corresponding auditory brainstem response (i.e. sensory perception) to the ultrasonic calls in the hummingbirds producing those calls.

Mechanics of Polyropylene-Seed-Coat-Fibres Composites AndPolyropylene –Wood Fibres Composites-A Comparative Study

Forestry by-products have potential applications as components of wood composites. Replacement of conventional pine radiata wood-fibres by the fibres from the seeds (SCF) of the by-products, require determining and optimizing the mechanical properties to producing highest quality products. Response to mechanical stress is an important aspect to consider towards partial or full replacement of the wood-fibres by SCFs. In the present study the critical strain energy release rate, and the fracture toughness are derived from the published data. The present work uses rules of mixture to derive the mechanical and the physical properties of the SCF and relates the performance of the composites of the wood-fibres and the SCF to chemical composition, dispersion, weight and Vf of the fibres. We have also derived the Gc, the critical strain energy release rate, KIC, the fracture toughness of the composites.

Toward a model for predicting magnetic susceptibility of bedrock regolith and soils

One of the Department of Defense's most pressing environmental problems is the efficient detection and identification of unexploded ordnance (UXO). In regions of highly magnetic soils, magnetic and electromagnetic sensors often detect anomalies that are of geologic origin, adding significantly to remediation costs. In order to develop predictive models for magnetic susceptibility, it is crucial to understand modes of formation and the spatial distribution of different iron oxides. Most rock types contain iron and their magnetic susceptibility is determined by the amount and form of iron oxides present. When rocks weather, the amount and form of the oxides change, producing concomitant changes in magnetic susceptibility. The type of iron oxide found in the weathered rock or regolith is a function of the duration and intensity of weathering, as well as the original content of iron in the parent material. The rate of weathering is controlled by rainfall and temperature; thus knowing the climate zone, the amount of iron in the lithology and the age of the surface will help predict the amount and forms of iron oxide. We have compiled analyses of the types, amounts, and magnetic properties of iron oxides from soils over a wide climate range, from semi arid grasslands, to temperate regions, and tropical forests. We find there is a predictable range of iron oxide type and magnetic susceptibility according to the climate zone, the age of the soil and the amount of iron in the unweathered regolith.

Is Australia positioned to take advantage of biosimilars?

Australia currently has a small generic and biosimilar industry despite having a good track record in biomedical research and a sound reputation in producing high quality but small volume biological pharmaceuticals. In recent times, Australia has made incremental changes to its regulation of biosimilars – in patent registration, in the use of commercial confidential information, and in remuneration. These improvements, together with Australia’s geographical proximity and strong trade relationship with the Asian biocluster have positioned Australia to take advantage of potential public cost savings from the increased use of biosimilars.

Wide-band spectral power fluctuations characterize the response of simulated cortical networks to increasing stimulus intensity

The hippocampus is an anatomically distinct region of the medial temporal lobe that plays a critical role in the formation of declarative memories. Here we show that a computer simulation of simple compartmental cells organized with basic hippocampal connectivity is capable of producing stimulus intensity sensitive wide-band fluctuations of spectral power similar to that seen in real EEG. While previous computational models have been designed to assess the viability of the putative mechanisms of memory storage and retrieval, they have generally been too abstract to allow comparison with empirical data. Furthermore, while the anatomical connectivity and organization of the hippocampus is well defined, many questions regarding the mechanisms that mediate large-scale synaptic integration remain unanswered. For this reason we focus less on the specifics of changing synaptic weights and more on the population dynamics. Spectral power in four distinct frequency bands were derived from simulated field potentials of the computational model and found to depend on the intensity of a random input. The majority of power occurred in the lowest frequency band (3-6 Hz) and was greatest to the lowest intensity stimulus condition (1% maximal stimulus). In contrast, higher frequency bands ranging from 7-45 Hz show an increase in power directly related with an increase in stimulus intensity. This trend continues up to a stimulus level of 15% to 20% of the maximal input, above which power falls dramatically. These results suggest that the relative power of intrinsic network oscillations are dependent upon the level of activation and that above threshold levels all frequencies are damped, perhaps due to over activation of inhibitory interneurons.

Improved fabrication of melt electrospun tissue engineering scaffolds using direct writing and advanced electric field control

Direct writing melt electrospinning is an additive manufacturing technique capable of the layer-by-layer fabrication of highly ordered 3d tissue engineering scaffolds from micron-diameter fibres. The utility of these scaffolds, however, is limited by the maximum achievable height of controlled fibre deposition, beyond which the structure becomes increasingly disordered. A source of this disorder is charge build-up on the deposited polymer producing unwanted coulombic forces. In this study we introduce a novel melt electrospinning platform with dual voltage power supplies to reduce undesirable charge effects and improve fibre deposition control. We produced and characterised several 90° cross-hatched fibre scaffolds using a range of needle/collector plate voltages. Fibre thickness was found to be sensitive only to overall potential and invariant to specific tip/collector voltage. We also produced ordered scaffolds up to 200 layers thick (fibre spacing 1 mm, diameter 40 μm) and characterised structure in terms of three distinct zones; ordered, semi-ordered and disordered. Our in vitro analysis indicates successful cell attachment and distribution throughout the scaffolds, with little evidence of cell death after seven days. This study demonstrates the importance of electrostatic control for reducing destabilising polymer charge effects and enabling the fabrication of morphologically suitable scaffolds for tissue engineering.

Development of a pilot-scale bacterial fermentation for plasmid-based biopharmaceutical production using a stoichiometric medium

The recognition of the potential efficacy of plasmid DNA (pDNA) molecules as vectors in the treatment and prevention of emerging diseases has birthed the confidence to combat global pandemics. This is due to the close-to-zero safety concern associated with pDNA vectors compared to viral vectors in cell transfection and targeting. Considerable attention has been paid to the potential of pDNA vectors but comparatively less thought has been given to the practical challenges in producing large quantities to meet current rising demands. A pilot-scale fermentation scheme was developed by employing a stoichiometrically-designed growth medium whose exceptional plasmid yield performance was attested in a shake flask environment for pUC19 and pEGFP-N1 transformed into E. coliDH5α and E. coliJM109, respectively. Batch fermentation of E. coliDH5α-pUC19 employing the stoichiometric medium displayed a maximum plasmid volumetric and specific yield of 62.6 mg/L and 17.1 mg/g (mg plasmid/g dry cell weight), respectively. Fed-batch fermentation of E. coliDH5α-pUC19 on a glycerol substrate demonstrated one of the highest ever reported pilot-scale plasmid specific yield of 48.98 mg/g and a volumetric yield of 0.53 g/L. The attainment of high plasmid specific yields constitutes a decrease in plasmid manufacturing cost and enhances the effectiveness of downstream processes by reducing the proportion of intracellular impurities. The effect of step-rise temperature induction was also considered to maximize ColE1-origin plasmid replication.

Process engineering aspects of plasmid-based biopharmaceuticals production : tackling the threatening vaccine shortages to prevent global pandemics

Infectious diseases such as SARS, influenza and bird flu have the potential to cause global pandemics; a key intervention will be vaccination. Hence, it is imperative to have in place the capacity to create vaccines against new diseases in the shortest time possible. In 2004, The Institute of Medicine asserted that the world is tottering on the verge of a colossal influenza outbreak. The institute stated that, inadequate production system for influenza vaccines is a major obstruction in the preparation towards influenza outbreaks. Because of production issues, the vaccine industry is facing financial and technological bottlenecks: In October 2004, the FDA was caught off guard by the shortage of flu vaccine, caused by a contamination in a US-based plant (Chiron Corporation), one of the only two suppliers of US flu vaccine. Due to difficulties in production and long processing times, the bulk of the world's vaccine production comes from very small number of companies compared to the number of companies producing drugs. Conventional vaccines are made of attenuated or modified forms of viruses. Relatively high and continuous doses are administered when a non-viable vaccine is used and the overall protective immunity obtained is ephemeral. The safety concerns of viral vaccines have propelled interest in creating a viable replacement that would be more effective and safer to use.

Creation of protein loaded biodegradable microparticles via ultrasonic atomization suitable for nasal delivery

Improved biopharmaceutical delivery may be achieved via the use of biodegradable microspheres as delivery vehicles. Biodegradable microspheres offer the advantages of maintaining sustained protein release over time whilst simultaneously protecting the biopharmaceutical from degradation. Particle samples produced by ultrasonic atomization were studied in order to determine a feed stock capable of producing protein loaded poly-ε-caprolactone (PCL) particles suitable for nasal delivery (i.e., less than 20 μm). A 40 kHz atomization system was used with a 6 mm full wave atomization probe. The effect of solids percent, feed flow rate, volumetric ratio of the polymer stock to the protein stock, and protein concentration in the protein stock on particle size characteristics were determined. It was shown that feed stocks containing 100 parts of 0.5 or 1.0% w/v PCL in acetone with one part 100 mg ml -1 BSA and 15 mg ml -1 PVA produced particles with a mass moment diameter (D[4,3]) of 13.17 μm and 9.10 μm, respectively in addition to displaying high protein encapsulation efficiencies of 93 and 95%, respectively. The biodegradable PCL particles were shown to be able to deliver encapsulated protein in vitro under physiological conditions.

Plasmid DNA purification and formulation for vaccine applications

Plasmid DMA offers the promise of a new generation of pharmaceuticals that will address the often overlooked issue of vaccine production by offering a simple and reproducible method for producing a vaccine. Through reverse engineering, production could be reduced from up to 9 months to as little as 1 month. Simplified development and faster turn-around times means that DMA offers a solution to the vaccine crisis and will help to contain future viral outbreaks by enabling the production of a vaccine against new viral strains in the shortest possible time. Work currently being completed in the area of plasmid DMA production, purification and encapsulation will be presented.

Bio-hydrogen production from food waste through anaerobic fermentation

In order to protect our planet and ourselves from the adverse effects of excessive CO2 emissions and to prevent an imminent non-renewable fossil fuel shortage and energy crisis, there is a need to transform our current ‘fossil fuel dependent’ energy systems to new, clean, renewable energy sources. The world has recognized hydrogen as an energy carrier that complies with all the environmental quality and energy security, demands. This research aimed at producing hydrogen through anaerobic fermentation, using food waste as the substrate. Four food waste substrates were used: Rice, fish, vegetable and their mixture. Bio-hydrogen production was performed in lab scale reactors, using 250 mL serum bottles. The food waste was first mixed with the anaerobic sewage sludge and incubated at 37°C for 31 days (acclimatization). The anaerobic sewage sludge was then heat treated at 80°C for 15 min. The experiment was conducted at an initial pH of 5.5 and temperatures of 27, 35 and 55°C. The maximum cumulative hydrogen produced by rice, fish, vegetable and mixed food waste substrates were highest at 37°C (Rice =26.97±0.76 mL, fish = 89.70±1.25 mL, vegetable = 42.00±1.76 mL, mixed = 108.90±1.42 mL). A comparative study of acclimatized (the different food waste substrates were mixed with anaerobic sewage sludge and incubated at 37°C for 31days) and non-acclimatized food waste substrate (food waste that was not incubated with anaerobic sewage sludge) showed that acclimatized food waste substrate enhanced bio-hydrogen production by 90 - 100%.

Moving identities : multiplicity, embodiment and the contemporary dancer

Currently, across dance studies, choreographies are usually discussed as representational of the choreographer, with little attention focused on the dancers who also bring the work into being. As well as devaluing the contribution that the dancer makes to the choreographic process, the dancer’s elision from mainstream discourse deprives the art form of a rich source of insight into the incorporating practices of dance. This practice-based research offers a new perspective on choreographic process through the experiential viewpoint of the participating dancer. It involves encounters with contemporary choreographers Rosemary Butcher (UK), John Jasperse (US), Jodi Melnick (US) and Liz Roche (Ire). Utilizing a mixed-mode research structure, it covers the creative process and performance of three solo dance pieces in Dublin in 2008, as well as an especially composed movement treatise, all of which are documented on the attached DVD. The main hypothesis presented is that the dancer possesses a moving identity which is a composite of past dance experience, anatomical structures and conditioned human movement. This is supported by explorations into critical theory on embodiment, including Pierre Bourdieu’s concept of ‘the habitus’. The moving identity is identified as accumulative, altering through encounters with new choreographic movement patterns in independent contemporary dance practice. The interior space of the dancer’s embodied experience is made explicit in chapter 3, through four discussions that outline the dancer’s creative labour in producing each choreographic work. Through adopting a postmodern critical perspective on human subjectivity, supported by Gilles Deleuze, Félix Guattari and Alain Badiou, among others, the thesis addresses the inherent challenges which face independent contemporary dancers within their multiple embodiments as they move between different choreographic processes. In identifying an emergent paradigmatic shift in the role of dancer within dance- making practices, this research forges a new direction that invites further dancer-led initiatives in practice-based research.

Composing an email : social interaction in a preschool classroom

The chapter contributes understandings of digitally mediated interactions in early childhood classrooms. Ethnomethodological and conversation analysis approaches are used to analyse a video-recorded episode of children and teacher composing an email in a preschool classroom. In their talk we find how the teacher directs the children to what counts procedurally, such as the components of an email, and the teacher’s moral work in producing a culturally correct way form of personal communication. Such considerations of situated examples can encourage investigations of digital practices that extend beyond operational skills to broader understandings of digital practices as cultural and situated activities.

Autologous human kidney proximal tubule epithelial cells (PTEC) modulate dendritic cell (DC), T cell and B cell responses

This is a comprehensive study of human kidney proximal tubular epithelial cells (PTEC) which are known to respond to and mediate the pathological process of a range of kidney diseases. It identifies various molecules expressed by PTEC and how these molecules participate in down-regulating the inflammatory process, thereby highlighting the clinical potential of these molecules to treat various kidney diseases. In the disease state, PTEC gain the ability to regulate the immune cell responses present within the interstitium. This down-regulation is a complex interaction of contact dependent/independent mechanisms involving various immuno-regulatory molecules including PD-L1, sHLA-G and IDO. The overall outcome of this down-regulation is suppressed DC maturation, decreased number of antibody producing B cells and low T cell responses. These manifestations within a clinical setting are expected to dampen the ongoing inflammation, preventing the damage caused to the kidney tissue.