Modeling and comparative analysis of carbon nanotube and boron nitride nanotube cantilever biosensors

This paper investigates the bending deformation of a cantilever biosensor based on a single-walled carbon nanotube (CNT) and single-walled boron nitride nanotube (BNNT) due to bioparticle detection. Through 3-D modeling and simulations, the performance of the CNT and BNNT cantilever biosensors is analyzed. It is found that the BNNT cantilever has better response and sensitivity compared to the CNT counterpart. Additionally, an algorithm for an electrostatic-mechanical coupled system is developed. The cantilever (both BNNT and CNT) is modelled by accounting that a conductive polymer is deposited onto the nanotube surfaces. Two main approaches are considered for the mechanical deformation of the nanotube beam. The first one is differential surface stress produced by the binding of biomolecules onto the surface. The second one is the charge released from the biomolecular interaction. Also, different ambient conditions are considered in the study of sensitivity. Sodium Dodisyl Sulphate (SDS) provides better bending deformation than the air medium. Other parameters including length of beam, variation of beam's location, and chiralities are considered in the design. The results are in excellent agreement with the electrostatic equations that govern the deformation of cantilever.

Identification of modulating residues defining the catalytic cleft of insulin-regulated aminopeptidase

Inhibition of insulin-regulated aminopeptidase (IRAP) has been demonstrated to facilitate memory in rodents, making IRAP a potential target for the development of cognitive enhancing therapies. In this study, we generated a 3-D model of the catalytic domain of IRAP based on the crystal structure of leukotriene A4 hydrolase (LTA4H). This model identified two key residues at the ‘entrance’ of the catalytic cleft of IRAP, Ala427 and Leu483, which present a more open arrangement of the S1 subsite compared with LTA4H. These residues may define the size and 3-D structure of the catalytic pocket, thereby conferring substrate and inhibitor specificity. Alteration of the S1 subsite by the mutation A427Y in IRAP markedly increased the rate of substrate cleavage V of the enzyme for a synthetic substrate, although a corresponding increase in the rate of cleavage of peptide substrates Leu-enkephalin and vasopressin was was not apparent. In contrast, [L483F]IRAP demonstrated a 30-fold decrease in activity due to changes in both substrate affinity and rate of substrate cleavage. [L483F]IRAP, although capable of efficiently cleaving the N-terminal cysteine from vasopressin, was unable to cleave the tyrosine residue from either Leu-enkephalin or Cyt6-desCys1-vasopressin (2–9), both substrates of IRAP. An 11-fold reduction in the affinity of the peptide inhibitor norleucine1-angiotensin IV was observed, whereas the affinity of angiotensin IV remained unaltered. In additionm we predict that the peptide inhibitors bind to the catalytic site, with the NH2-terminal P1 residue occupying the catalytic cleft (S1 subsite) in a manner similar to that proposed for peptide substrates.

Capturing dance : using motion capture analysis to enhance dance creation and performance

Opening keynote address.

Virtual Werribee : a planning support tool

Virtual Werribee is collaborative research in applying 3-D modelling and visualisation as a planning support tool in comparison to 2-D plans and drawings. It was a joint initiative involving Deakin University and the Wyndham City Council to demonstrate the use of 3-D visualisation for planning process in the actual context of a planning authority in Australia. The objective of this project was to assist the council in preparing for the revised Local Structure Plan. By reconstructing the council’s data into easily understood information, 3-D model and visualisation served as a verification and discussion tool for decision making. The integration of wider site context also provided a better understanding of the surrounding development areas. This could equip other stakeholders as well as the community to participate in council’s planning agenda activities, such as increasing the urban density and building heights limit.

Virtual Werribee included the development planning agenda, categorised as new, re-development and hypothetical. The modelling process progressed with sufficient data from the council. Some changes to the initial plan were made, including the use of CAD modelling software instead of GIS software, and production of a block model with selected detail buildings, instead of a full draped 3-D model. The council decided that the block model would be sufficient for their planning purposes. This was determined while taking into consideration the available facilities at the council.

The potentials of the model as a planning tool were demonstrated in this paper, and further compared to the council’s existing materials prepared by the project developers. The advantages of the 3-D interactive model and visualisation over the conventional materials have provided the council officer with a tool for better empowerment in the planning process. This was also evident in the increasing engagement level between the officer and the model as the process developed. As a result of this, the project scope has also expanded, finally covering the entire city.

While Virtual Werribee has the potential to better communicate council’s planning agendas to the stakeholders and the community, the key factor, coupled with its visualisation components, was its interactive capability. Property layers with aerial site image that provided a realistic background served as a virtual city platform for different users. Although limited in its analytic capability found in GIS software, this model offered high visualisation content to assist visual impact assessment through its interactive mode along with a series of still images and a simulation movie.

Investigation of cell shape effect on the mechanical behaviour of open-cell metal foams

The mechanical behaviours of metal foams greatly depend on their cell topology, including cell shape, cell size etc. as well as relative density and material properties of the cell wall. However, the cell shape effect on the mechanical behaviours of such materials appears to be ignored in previous research. In this paper, both analytic and finite element models are developed and employed to investigate the effect of cell shape on the mechanical behaviour of open-cell magnesium alloy (AZ91) foams under compression, including deformation modes and failure modes. For numerical modelling, both two-dimensional (2-D) and three-dimensional (3-D) finite element models are developed to predict the compressive behaviours of typical open-cell metal foams and capture the deformation modes and failure mechanisms. Two typical cell shapes i.e. cubic and diamond are taken into consideration. To validate these models, the analytic and numerical results are compared to the experimental data. Both the numerical and experimental data indicate that the cell shape significantly affects the compression behaviour of open-cell metal foams. In general, numerical results from the three-dimensional solid-element model show better agreement with the experimental results than those from other finite element models.

Model-based combined tracking and resolution enhancement

Wide area surveillance requires high-resolution images of the object of interest derived possibly from only low-resolution video of the whole scene. We propose a combined tracking and resolution enhancement approach that increases the resolution of the object of interest during tracking. The key idea is the use of an object-specific 3D mesh model with which we are able to track non-planar objects across a large number of frames. This model is subdivided such that every triangle is smaller than a pixel when projected into the image to facilitate super-resolution on the model rather than on the image. We apply our approach to faces and show that it outperforms interpolation methods by achieving resolution enhancement, while being less blurred.