NeuroEngineering Research Lab
Date: Monday 2 December 2013
Micelles and vesicles have long been proposed as carriers for low molecular weight molecules including drugs. The core-shell systems are found to be useful for the encapsulation of hydrophobic drugs in the core while maintaining the water solubility of the system with the hydrophilic shell. In addition, their sizes between 20–100 nm makes them perfect to target the drug passively to the tumour. Despite their high stability, micelles still tend to break up upon dilution once they reached their lower critical aggregation concentration. Several approaches have been undertaken to stabilise these structures using the crosslinking of the core or shell.
This talk will discuss how the synthesis of the underlying block copolymers, which build up these core-shell nanoparticles. The chemistry of these polymers does not only determine how big these particles are, but it can also influence drug encapsulation and the …
Date: Monday 25 November 2013
The pattern of cortical folding that is unique to each human brain arises during development from a series of physiological and biomechanical factors that remain the focus of on-going research. To analyse patterns of cortical folding, MRI has been widely used in the computation of metrics based on morphometric analyses.
This talk will firstly present the use of a Spherical Harmonic representation of the cortical surface to measure cortical complexity, including prediction of intermediate folding states during development. Secondly, a modified gyrification index computed using the Laplace Beltrami operator will be presented. This method uses the intrinsic geometry of the cortex, rather than being constrained by slice orientation. Cortical folding is quantified using a metric based on eigenvalues of the Laplace Beltrami operator. It will be demonstrated that such metrics are useful measures of cortical gyrification …
Biomedical Engineering Seminar: Biological and engineering challenges in biomanufacture of human platelets for transfusion
Date: Monday 11 November 2013
Platelets are small, enucleated blood cells that play critical roles in maintaining blood vessel integrity and tissue repair. Platelets survive for only 5–7 days and their number within blood needs to be maintained above a critical threshold to prevent spontaneous bleeding. In severe cases of low platelet counts, platelet transfusion is the treatment of choice. However, globally, the supply of fresh human platelets from volunteer donors often outstrips demand.
This talk discusses technology developed for large-scale biomanufacture of these cells from haemopoietic stem cells. An underpinning aspect of this technology development is the desire to replicate the process of platelet production in vivo. This is a truly amazing biological process involving controlled differentiation of stem cells to ultimately produce a large polyploid cell, the megakaryocyte and the final conversion of these cells to platelets. …
Date: Monday 21 October 2013
The use of surface initiated polymerisation (SIP) methods have become widespread as a method of modifying surfaces, particularly in the formation of polymer brush coatings and to produce coatings with advanced functionality. In the last six years CSIRO has developed and implemented a method of SIP which relies on the use of macro-initiators/iniferters (mI) or macro-chain transfer agents (mCTA) that are covalently bonded to a surface and act as initiator or chain growth sites for the formation of polymer brush coatings with very well defined properties. The method is particularly useful for controlled or living polymerisation mechanisms such as Radical Addition-Fragmentation chain Transfer (RAFT), Atom Transfer Radical Polymerisation (ATRP) and Initiator-Transfer-Termination (Iniferter) and can be applied to a variety of substrate materials with either simple or complex geometries.
This talk will discuss the …
Date: Monday 14 October 2013
In 2012 about 50,000 Australians suffered a stroke, and about 65% of them remain with a physical disability. In order to improve the neurorehabilitation efficiency, and the patients recovery, therapists are naturally trying to use new technologies in the rehabilitation process. Robotics systems were thus introduced in the field of neurorehabilitation in the seventies.
This talk will deal with the particular interest of robotics exoskeletons which have the ability to interact with the human limb at several contact points, not only at the hand level. This specific ability constitutes a serious advantage for rehabilitation applications but also bring new problems and more complexity in terms of control. Two new exoskeleton control methods dedicated to neurorehabilitation have thus been developed to fully take advantage of this specific structure. The first one provide a passive mobilization of the patient limb …
Continuous Wave Nuclear Magnetic Resonance - Investigation of off-resonance effects of Rabi modulated excitation
Date: Monday 7 October 2013
In this biomedical engineering seminar magnetic resonance imaging (MRI) will be considered and how it has been adopted as a common scanning technique for medical diagnostic use. MRI uses pulsed excitation protocols, in which the object of interest is excited by short-lived pulses, and measurements taken as the object’s magnetisation returns to equilibrium. Researchers are investigating an alternative method of continuous wave excitation, in which the object is continuously excited and measurements are simultaneously performed, to provide a potentially richer information source about the object.
Preliminary work has focused on characterisation of the nuclear magnetic resonance signal during Rabi modulated continuous wave excitation. Under this form of excitation, the bulk magnetisation reaches a periodic steady-state, which can be approximated by a Fourier expansion of the Bloch equation, restricted to harmonics …
Date: Monday 23 September 2013
The aim of this project is to model the effect of electrical stimulation on local neural activity in the brain. This will contribute to a larger project of systematic controlling of epileptic seizures through a model-based strategy. Epileptic seizures are the result of an uncontrolled burst of electrical activity in the brain, which can lead to convulsions or loss of consciousness. The most common form of treatment for epilepsy is via drugs. However, they are not effective for approximately one third of epilepsy patients. An alternative therapy is to apply electrical stimulation to control abnormal brain activity.
In order for the developed model to be clinically applicable, the appropriate functional form and physiological parameters need to be identified to make it applicable to cortical tissue stimulated by surface electrode arrays. The whole model will then …
Date: Monday 9 September 2013
Venue: Room 202 (Masters Seminar Room 2) , Old Metallurgy Building
Presbyopia is a condition in which the aging eye loses its ability to focus on close objects (accommodation), due to hardening of the natural lens. While wearing reading glasses remains the most common solution to this condition they cannot provide dynamic accommodation due to their fixed focal length. An attractive potential solution to presbyopia involves replacing the hardened natural lens with a gel soft enough to allow accommodation.
In this study, functional polysiloxanes macromonomers have been investigated as possible candidate materials to replace the hardened natural lens for correction of presbyopia. This requires a biostable and biocompatible polysiloxane to be injected into the capsular bag in a liquid form and cured in situ to form a soft gel. These polymers are designed to mimic the optical and mechanical properties of a young person’s natural lens by having a …
Date: Monday 2 September 2013
Stochasticity is an essential aspect of biochemical processes at the cellular level. We now know that living cells take advantage of stochasticity in some cases and counteract stochastic effects in others.The presenter will use examples to discuss how cells process information and discuss the relative roles that analog and digital signal processing play in cellular systems. In the response of Escherichia coli to nitrogen starvation, for example, researchers find strong evidence for both types of information processing. Using time-resolved proteomic, metabolomic and transcriptomic data researchers can show that the nitrogen state can be computed with high fidelity. The high accuracy - the channel capacity amounts to approximately 10 bits - reflects a strong evolutionary impetus on optimizing sensing and correctly responding to the environmental nitrogen state. Combining different …
Biomedical Engineering Seminar: Systems Biology of drug response and metastasis through multi-scale modeling, novel biomaterials and high-throughput imaging
Date: Monday 26 August 2013
Cancer cell migration, signaling and response to therapeutics have historically been carried out in two-dimensional environments that are far from in vivo. These environments create artificial polarities, mediate unrealistic cell-matrix interactions and lead to signaling cascades that paint an incomplete and inaccurate picture of cancer cell behavior in vivo. Consequently, our understanding of matrix mechanical regulation of therapeutic efficacy and chemoresistance is qualitative and fragmented. Additionally, current computational models are unable to connect biochemical signaling events at the molecular level with biomechanical processes observed in native like 3D environments making the predictive power of models limited in their scope.
Using a combination of multi-scale modeling approaches (deterministic, finite element, molecular simulations) with development …
Date: Monday 19 August 2013
Layer-by-layer (LbL)-assembled carriers have recently emerged as a promising class of materials for applications in biology with studies progressing from in vitro to in vivo. The versatility of LbL assembly coupled with particle templating allows the generation of capsules with specific properties (eg., stimuli-responsive, efficient cargo encapsulation), thus offering new opportunities in drug delivery. In this presentation, the interactions between human cancer cells and the LbL capsules will be discussed. The focus will be placed on the internalization and intracellular trafficking of these particles. Based on the cellular interactions, several approached for drug encapsulation and controlled intracellular released will also be addressed in the talk. Taken together, these studies have highlighted the importance of understanding the complex cellular dynamics of particles in advanced …
Date: Monday 12 August 2013
This presentation will discuss methods for developing subject-specific mesoscopic neural models. The ability to create subject-specific models will enable estimation of normally hidden aspects of physiology. Imaging physiological parameters will lead to a greater understanding of diseases and provide new targets for novel therapies. The model-data fusion framework in this presentation is based on nonlinear Kalman filtering. In particular, we will demonstrate estimation accuracy using synthetic data before showing results from real intracranial EEG data. …
Biomedical Engineering Seminar: Atomic Force Microscopy Measurement of Fluid-Solid Interactions within Aggrecan Proteoglycan Networks
Date: Monday 29 July 2013
Venue: Greenwood Theatre, Building 193, Electrical and Electronic Engineering
The molecular structure and nanomechanical properties of aggrecan monomers extracted and purified from human articular cartilage from donors of different ages have recently been visualized and quantified via atomic force microscopy (AFM)-based imaging, force spectroscopy, and high bandwidth nano-rheology. AFM imaging enabled direct comparison of full length monomers at different ages. The demonstrably shorter glycosaminoglycan (GAG) chains observed in adult full length aggrecan monomers, compared to newborn monomers reflects markedly altered biosynthesis with age. These results provide molecular-level evidence of the effects of age on the conformational and nanomechanical properties of aggrecan, with direct implications for the effects of aggrecan nanostructure on macro-level properties of cartilage tissue. The presenter will discuss recent studies of brush layers of aggrecan from these …
Biomedical Engineering Seminar: The effect of morphology and intrinsic electrophysiology in shaping retinal ganglion cell responses
Date: Monday 24 June 2013
Venue: Greenwood Theatre, Building 193, Electrical and Electronic Engineering
Retinal ganglion cells (RGCs) display differences in their morphology and intrinsic electrophysiology. Matias Maturana will explore realistic, morphologically correct models of 200 ON and OFF RGCs, and test ionic channel densities in morphological compartments that are necessary to capture experimentally recorded phenomena. He will investigate the effect of the cell’s morphology on its impulse waveform, using the first and second-order time derivatives as well as phase plot features. Matias Maturana proposes that a combination of morphological and ionic features shape the cell’s impulse response and confirm that by simulations. In addition, he explore the ability of the constrained models of RGCs to respond to high frequency bi-phasic pulse train stimulation and show that cells’ morphology plays an important role in shaping cell responses.…
Biomedical Engineering Seminar: Vision processing for safe and efficient navigation with a visual prosthesis
Date: Monday 17 June 2013
Current and near-term visual prostheses are severely limited in their capacity to convey visual information about the scene to implantees. This has motivated consideration of how vision processing algorithms can be designed and used to maximise the bandwidth available, in order to improve functional outcomes for patients. In this talk the speaker will present an overview of recent and ongoing work at NICTA CRL towards the development of computer vision algorithms and novel visual representations to enhance the perception of scene structure in prosthetic vision. In particular, the presentation will outline recent work demonstrating how such algorithms may be used to emphasise low contrast ground obstacles, and encode the time-to-contact of objects posing an imminent threat of collision. Obstacle avoidance work has been shown to reduce collisions by close to 50% compared with …
Date: Monday 3 June 2013
The aim of this research seminar is to propose a framework to obtain patient-specific models for people with epilepsy who have focal seizures. Different biologically plausible models of the brain are reviewed, including methods that have been used to analyse and identify them. A novel framework is proposed to construct patient-specific models using Electrocorticographic (ECoG) data. To this end, the Jansen and Rit (1995) model of a cortical column is extended such that the model emulates transitions to and from seizures states. The extended model will be fitted (by an identification and validation method) to ECoG data. This framework may help us to describe the underlying mechanisms of initiation and termination of seizures in individual patients. Our next goal is to generalise our proposed frameworks by interconnecting the extended models, and fit them to multi-channel ECoG data …
Biomedical Engineering Seminar: The stellate microcircuit of the cochlear nucleus — design and optimisation of a biophysically-realistic neural network model
Date: Monday 29 April 2013
Biophysically-realistic neural network (BNN) models require quality design and optimisation methods in order to best advance understanding of complex neural processing. This talk presents a novel BNN model of the cochlear nucleus stellate microcircuit, which provides a robust spectral representation of sound and plays an essential part in speech communication. The model was optimised using rigorous sequential methods and simultaneous genetic algorithms. The results of the analysis demonstrate the utility of this approach for improving BNN models.…
Date: Monday 8 April 2013
Exercise renders a disproportionate load on the cardiac ventricles. Animal and human studies are concordant in demonstrating that right ventricle load (wall stress, work and oxygen demand), which is considerably less than for the left ventricle at rest, increases disproportionately during exercise. The result is that the right ventricle may be injured by prolonged intense exercise creating the potential for long term heart problems including serious arrhythmias.
This presentation describes possible mechanisms for arrhythmic heart remodelling by combining echocardiography and magnetic resonance imaging in real-time exercise studies. Repeatedly, the obtained results demonstrate that the focus of exercise changes in the heart should focus on the right ventricle and pulmonary circulation. The right ventricle’s unique shape, location and loading present specific issues …
Biomedical Engineering Seminar: Validating MEG/EEG finite element head models using a controlled rabbit experiment
Date: Monday 25 March 2013
In focal epilepsy, it is essential to accurately determine the location of the seizure focus for each patient. Electroencephalography (EEG) and magnetoencephalography (MEG) based source localisation is a promising non-invasive method to determine the location of the seizure focus. Validation of realistic MEG/EEG finite element head models for source localisation will be presented using a self-developed controlled in vivo rabbit experiment. The original findings are that skull defects influence the MEG and finite element head models can be used to account for skull defects in MEG and EEG.…
Biomedical Engineering Seminar: Requirements for the Robust Operant Conditioning of Neural Firing Rates
Date: Monday 18 March 2013
Operant conditioning experiments have shown that changes in the firing rates of individual neurons in the motor cortex of monkeys can be elicited. In these experiments, the firing rates of the neurons were measured using an implanted electrode, and the monkeys were presented with feedback based on these rates and rewarded for increasing them. Behavioural learning such as this is assumed to occur at the synaptic level and reward-modulated spike-timing-dependent plasticity (RSTDP) has previously been proposed as such a model.
In this study, the presenter will propose a generalization of the classical RSTDP model that can account for experiments where dopamine changes the amplitude of long-term potentiation and depression. Using analytical techniques and numerical simulations, classical RSTDP is compared with the proposed generalized model. The requirements for these models …
Biomedical Engineering Seminar: Realistic spiking models of octopus cell circuits of the mammalian auditory brainstem
Date: Monday 11 March 2013
Octopus cells are named after their unique shape, with dendrites oriented in one direction. They receive input from a large number of Auditory Nerve Fibers (>60) representing a broad frequency band. The talk covers three topics relating to the computational modelling of the behaviour and function of octopus cells:
- A multi-compartmental Hodgkin-Huxley model, combined with a realistic model of the auditory periphery was used to determine the importance of the octopus cells' dendritic delay. We found that this dendritic delay might compensate for systematic asynchrony across ANFs with different CFs.
- A modified leaky integrate-and-fire model with a simple dendritic delay to investigate the function of octopus cells output in the ventral nucleus of the lateral lemniscus. In particular, we used realistic sounds to investigate the effect when octopus …
Date: Monday 25 February 2013
Hossein Mokhtarzadeh (PhD student in Biomechanics) will be presenting the first seminar in our new Biomedical Engineering Seminar Series.
Landing is an inevitable physical activity in many sports such as basketball, soccer, and gymnastics. Upon landing, the anterior cruciate ligament (ACL) is one of the most susceptible knee structures to injury with a higher rate of incidence among female athletes.
Hossein Mokhtarzadeh will outline his study to investigate the biomechanics of landing maneuver to understand ACL injury mechanism. In this study, two experimental approaches were used to quantify the effects of muscle forces and impact loads on ACL loading: human motion capture and in-vitro experiments. It was found that it was not only the knee joint muscles but also the coordination of muscles surrounding the ankle joint that together play a major role in protecting ACL from injury; also the results …
Date: 2:00pm Tuesday 29 January 2013
The NeuroEngineering Laboratory Seminars recommence for 2013 with a guest speaker from Pennsylvania State University, Pro. Steven Schiff. This promises to be an excellent seminar so anyone interested is encouraged to attend.
Title: Adventures in Control Theory: Hydrocephalus, Seizures, Climate, Dung, and the Neonatal Septisome
Abstract: Modern model-based control theory brings us optimal estimation of state of dynamical systems, even when those dynamics are floridly nonlinear as in many biological processes. Because our understanding of biology and disease has only relatively recently given us models of sufficient fidelity to warrant inclusion in control models, and because the engineering methods to incorporate complex nonlinear models are also recently developed, there are vast applications to consider exploring. This talk will …
Professor David Grayden
T: +61 3 8344 5234