Characterization of high fluid strain micro contractions to study the stress on biological fluids

Microfluidics has the potential to enhance the understanding of the biological fluids under strain, due to the laminar nature of the fluid and the possibility to mimic the real conditions. We present advances on charaterization of a microfluidic platform to study high strain rate flows in the transport of biological fluids. These advances are improvements on the reproduction of a  constant extensional strain rate using micro contractions and development of 3D numerical models. The micro geometries have been fabricated in polydimethyl siloxame (PDMS) using standard soft-lithography techniques with a photolithographically patterned mold. A comparison of some microcontractions with different funnel characteristics is presented. The Micro Particle Image Velocimetry technique has been applied to validate the numerical simulations. We demonstrate the use of microfluidics in the reproduction of a large range of controllable extensional strains that can be used in the study of the effect of flow on biological fluids.

Hydrodynamic flow focusing to study the isolated effects of the flow components

Biological fluids such as blood, proteins and DNA solutiosn moving within fluidic channels can potentially be exposed to high level of shear, extension or mixed stress, either in vitro such as industrial processing of blood products or in vivo such as ocurrs in some pathological conditions. This exposure to a high level of strain can trigger some reactions. In most of the cases the nature of the flow is mixed with shear and extensional components. The ability ot isolate the effects of each component is critical in order to understand the mechanisms behind the reactions and potentially prevent them. Applying hydrodynamic flow focusing, we present in this investigation the characterization of microchannels that allow study of the regions of high shear or high extension strain rate. Micro channels were fabricated in polydimethyl siloxane (PDMS)  using standard soft-lithography techniques with a photolithographically patterned mold. Characterization of the regions with high shear and high extension strain rate is presented. Computational Fluid Dynamics (CFD) simulations in three dimensions have been carried out to gain more detailed local flow information, and the results have been validated experimentally. A comparison between the numerical models and experiment and is presented. The advantages of microfluidic flow focusing in the study  of the effects of shear and extension strain rates for biological fluids are outlined.

Mixing characterisation for a serpentine microchannel equipped with embedded barriers

This paper describes the design, simulation, fabrication and experimental analysis of a passive micromixer for the mixing of biological solvents. The mixer consists of a T-junction, followed by a serpentine microchannel. the serpentine has three arcs, each equipped with circular barriers that are patterned as two opposing triangles. >The barriers are engineered to induce periodic perturbations in the flow field and enhance the mixing. CFD (Computational Fluid Dynamics) method is applied to optimise the geometric variables of the mixer before fabrication. The mixer is made from PDMS (Polydimethylsiloxane) using photo- and soft-lithography techniques. Experimental measurements are performed using yellow and blue food dyes as the mixing fluids. The mixing is measured by analysing the composition of the flow's colour across the outlet channel. The performance of the mixer is examined in a wide range of flow rates from 0.5 to 10 µl/min. Mixing efficiencies of higher than 99.4% are obtained in the experiments confirming the results of numerical simulations. The proposed mixer can be employed as a part of lab-on-a-chip for biomedical applications.

Molding micropatterns of elasticity on PEG-based hydrogels to control cell adhesion and migration

We present an innovative and simple, soft UV lithographic method “FIll-Molding In Capillaries” (FIMIC) that combines soft lithography with capillary force driven filling of micro-channels to create smooth hydrogel substrates with a 2D micro-pattern on the surface. The lithographic procedure involves the molding of a polymer; in our case a bulk PEG-based hydrogel, via UV-curing from a microfabricated silicon master. The grooves of the created regular line pattern are consequently filled with a second hydrogel by capillary action. As a result, a smooth surface is obtained with a well-defined pattern design of the two different polymers on its surface. The FIMIC method is very versatile; the only prerequisite is that the second material is liquid before curing in order to enable the filling process. In this specific case we present the proof of principle of this method by applying two hydrogels which differ in their crosslinking density and therefore in their elasticity. Preliminary cell culture studies on the fabricated elasticity patterned hydrogels indicate the preferred adhesion of the cells to the stiffer regions of the substrates, which implies that the novel substrates are a very useful platform for systematic cell migration studies, e.g. more fundamental investigation of the concept of “durotaxis”

Cultural equality and its soft power against terrorism

This book is a collection of papers originally presented at a workshop entitled 'After Nine Eleven: Ethics in the Time of Terror' hosted by Monash University on 24 June 2005. The workshop participants included members of the Ethics of War and Peace (EWAP) working group which was inaugurated at the first Oceanic Conference on International Studies in July 2004. EWAP provides a cross-disciplinary forum for scholars and non-academic professionals to exchange and debate ideas on topics including the ethics of armed intervention, the Just War, pacifist ethics, international humanitarian law, ethics in the military profession, and the relationship between law, ethics and politics.

The chapters within this book examine themes including 'lesser evils' and 'dirty hands' in the fight against terrorism, the ethics of intelligence gathering, humanitarian intervention, terrorism and the North-South divide, cultural equality as a response to terrorism, human rights and counterterrorism legislation, and the ethics of defending against 'bioterrorism'. 

Contributors include Alex Bellamy and Richard Devetak (University of Queensland), Baogang He (Deakin University), Christopher Michaelsen (Office for Democratic Institutions and Human Rights, Organization for Security and Co-operation in Europe), Jeremy Moses (University of Canterbury), Christian Enemark and Hugh Smith (University of New South Wales, Australian Defence Force Academy).

Using soft systems methodology to address supply chain management problems

This paper reports an investigation of if, and how, Soft Systems Methodology (SSM) might.be used to facilitate better management of industry supply chains. In two workshops involving supply chain managers from the Textile Clothing and Footwear (TCP) industry and industry facilitators, ways in which SSM techniques might supplement existing Supply Chain Management (SCM) workshop approaches have been explored. Specifically, the placement of SSM techniques within a workshop setting, reactions to the techniques, perceived reasons for using SSM, together with strengths and difficulties encountered, have been examined.

The effects of target length on the visual control of step length for hard and soft impacts

Adjustments to gait were examined when positioning the foot within a narrow target at the end of an approach for two impact conditions, hard and soft. Participants (6 M, 6 F) ran toward a target of three lengths along a 10-m walkway consisting of two marker strips with alternating black and white 0.5-m markings. Five trials were conducted for each target length and impact task, with trials block randomized between the 6 participants of each gender. A 50-Hz digital video camera panned and filmed each trial from an elevated position adjacent to the walkway. Video footage was digitized to deduce the gait characteristics. A linear speed/accuracy tradeoff between target length and approach time was found for both impact tasks (hard, r = 0.99, p < 0.01; soft, r = 0.96, p < 0.05). For the hard-impact task, visual control time increased linearly (r = 0.99, p < 0.05) when whole-body approach velocity decreased. Visual control time was unaffected by whole-body approach velocity in the soft-impact task. A constant tau-margin of 1.08 describes the onset of visual control when approaching a target while running, with the control of braking during visual control described by a tau-dot of –0.85. Further research is needed to examine the control of braking in different targeting tasks.

Caffeine as a flavor additive in soft-drinks

Over 60% of soft-drinks sold in the United States contain caffeine, a mildly addictive psycho-active chemical, as a flavor additive. Using sweeteners as controls, we assessed whether caffeine has flavor activity in a cola soft-drink. A forced-choice triangle discrimination methodology was used to determine detection thresholds of caffeine in sweeteners and a cola beverage. The subjects (n=30, 28 female, 23±4 years old) were trained tasters and completed over 1600 discrimination tests during the study. The mean detection thresholds for caffeine in the sweet solutions were: 0.333±0.1 mM sucrose; 0.467±0.29 mM aspartame; 0.462±0.3 mM sucralose, well below the concentration in common cola beverages (0.55–0.67 mM). A fixed concentration of caffeine, corresponding to the concentration of caffeine in a common cola beverage (0.67 mM) was added to the sweeteners and a non-caffeinated cola beverage. Subjects could distinguish between caffeinated and non-caffeinated sweeteners (p<0.001), but all subjects failed to distinguish between caffeinated and non-caffeinated cola beverage (p=1.0). Caffeine has no flavor activity in soft-drinks yet will induce a physiologic and psychologic desire to consume the drink.

Translocation of the socially complex black-eared miner manorina melanotis: a trial using hard and soft release techniques

We translocated five colonies of the highly social and co-operatively breeding Black-eared Miner Manorina melanotis, an endangered Australian honeyeater. Two colonies were released immediately (hard release) and two colonies were housed in aviaries for up to a week on-site and then supplied with food for a further week following release (soft release). A fifth colony was released using a combination of methods. All four hard and soft released colonies contained dependent fledglings at the time of release. This appears to be the first translocation of a co-operative species where intact colonies containing multiple breeding females, each with a suite of helpers have been translocated successfully. Both hard and soft release treatments appeared equally successful during an initial monitoring period of up to two months. All four colonies maintained social cohesion, and displayed high levels of survival and site fidelity. Both hard release and one soft release colony attempted to breed within 600 m of their release site within eight weeks of release. The other soft release colony bred 12 months later. We believe the inclusion of dependent young in each translocated colony provided a focus for translocated colonies that promoted site faithfulness and colony cohesion. Results of long-term monitoring remain inconclusive and it is recommended that monitoring be repeated during several future breeding events. Given our findings, we recommend that when translocating highly social species every effort is made to translocate the entire group, hard release techniques be applied and stimuli that enhance group cohesion and site faithfulness (the presence of dependent young) be exploited.

Soft-sediment deformation structures in the middle permian Wandrawandian siltstone, southern Sydney basin: implications for depositional environment and basin tectonics

The Middle Permian Wandrawandian Siltstone at Warden Head near Ulladulla in the southern Sydney Basin is dominated by fossiliferous siltstone and mudstone, with a large amount of dropstones (lonestones) and some pebbly sandstone beds. Two general types of deposits are recognised from the cliff succession in view of the timing and mechanism of their formation. One is represented by the background (or primary) deposits of offshore to slope environments with abundant dropstones of glacial marine origin. This facies occurs throughout the cliff sections at Warden Head. The second type is distinguished by secondary, soft-sediment deformational deposits and structures of the primary (background) deposits, and comprises three successive layers of sandy mudstone dikes. In the second type of deposit, metre scale, laterally extensive syn-depositional slump deformation structures occur extensively in the middle part of the Wandrawandian Siltstone. The deformation structures vary in morphology and pattern, including large-scale complex-type folds, flexural stratification, concave-up structures, small-magnitude -faults accompanied by folding and brecciation. The slumps and associated syn-depositional structures are herein attributed to penecontemporaneous deformations of soft sediments (mostly mud and silty mud), formed as a result of mass movement of unconsolidated and/or semi-consolidated substrate following earthquake events. The occurrence of the earthquake event deposits (or seismites) at Warden Head supports the current view that the Sydney Basin was located in a back-arc setting near the New England magmatic arc on an active continental margin during the Middle Permian, and the timing of the earthquake events is here interpreted to indicate the onset of the Hunter Bowen Orogeny in the southern Sydney Basin.

Soft tissue modelling for haptic rendering in virtual environments

This paper focuses on the development of a haptic recording and modelling system. Currently being evaluated for multiple uses in surgery and manufacturing, this recording system evaluates haptic data captured via a robotic ann coupled with real time high-resolution load cell. This data is then analysed and validated against previous samples and a generated model before being logged for playback during simulation and training of a human operator. 3D models of point force interactions are created allowing unique visuals to be presented to a user. Primarily designed for the medical field, recorded results of soft tissue cutting have been presented.