Current developments and future challenges for the creation of aortic heart valve

The concept of tissue-engineered heart valves offers an alternative to current heart valve replacements that is capable of addressing shortcomings such as life-long administration of anticoagulants, inadequate durability, and inability to grow. Since tissue engineering is a multifaceted area, studies conducted have focused on different aspects such as hemodynamics, cellular interactions and mechanisms, scaffold designs, and mechanical characteristics in the form of both in vitro and in vivo investigations. This review concentrates on the advancements of scaffold materials and manufacturing processes, and on cell–scaffold interactions. Aside from the commonly used materials, polyglycolic acid and polylactic acid, novel polymers such as hydrogels and trimethylene carbonate-based polymers are being developed to simulate the natural mechanical characteristics of heart valves. Electrospinning has been examined as a new manufacturing technique that has the potential to facilitate tissue formation via increased surface area. The type of cells utilized for seeding onto the scaffolds is another factor to take into consideration; currently, stem cells are of great interest because of their potential to differentiate into various types of cells. Although extensive studies have been conducted, the creation of a fully functional heart valve that is clinically applicable still requires further investigation due to the complexity and intricacies of the heart valve.

Exploiting ungrounded tactile haptic displays for mobile robotic teleoperation

Teleoperated mobile robotics offer potential use in a variety of different real-world applications including hazardous materials handling, urban search and rescue and explosive ordnance handling and disposal. Recent research discusses the use of Haptic technology in increasing task immersion and teleoperator performance. This work investigates the utility of low-cost, ungrounded tactile haptic interfaces in mobile robotic teleoperation. In order to achieve the desired implementation using only tactile sensation presents distinct challenges. Innovative haptic control methodologies providing the teleoperator with intuitive motion control and task-relevant haptic augmentation are presented within this paper.

Exploiting ungrounded tactile haptic displays for mobile robotic teleoperation

Teleoperated mobile robotics offer potential use in a variety of different real-world applications including hazardous materials handling, urban search and rescue and explosive ordnance handling and disposal. Recent research discusses the use of Haptic technology in increasing task immersion and teleoperator performance. This work investigates the utility of low-cost, ungrounded tactile haptic interfaces in mobile robotic teleoperation. In order to achieve the desired implementation using only tactile sensation presents distinct challenges. Innovative haptic control methodologies providing the teleoperator with intuitive motion control and task-relevant haptic augmentation are presented within this paper.

Thermodynamic and kinetic modelling hydrogenation of titanium particles and sheets

Use of hydrogen as a temporary alloying element in titanium alloys is an attractive approach to improve the mechanical properties of the materials, enhance processability and thereby reduce manufacturing costs. In this paper, the hydrogen diffusion process and the phase transformation both between titanium particles and in titanium sheets were computationally simulated to analyze the mechanism of hydrogen diffusion in different phases (α-Ti, β-Ti and TiHx). With the simulation based on the thermodynamics and kinetics, quantitative behaviors of the hydrogen diffusion and the phase transformation were analyzed. The simulation results provide an insight into the diffusion process and improve the fundamental understanding of the mechanism of diffusion and phase transformation.

Lifelong learning, the knowledge economy and professional development

There is increasing rhetoric surrounding the concepts of lifelong learning and the knowledge economy (Peters, 2001); specifically e-learning and web-based learning environments. This paper seeks to explore the journeys of two professionals from two separate disciplines and work environments located in one higher-education institution where there is an increasing push to develop learning materials using online and other e-learning technologies.

With the steady shift from traditional learning, online learning is now playing an integral part of course delivery at the Australian regional university where the authors work. A contextual analysis of online learning within the broader views of the institution provides examples of discourses relating to online environments, knowledge management, and the professional development of the participants.

This discussion draws on the concepts of lifelong learning (Crowley, 2002; Serim & Murray, 2003) and embeds them within an online learning environment. Exploration of the multiple workplace environments within the institution under review demonstrates one way in which educators can embrace and position themselves as they negotiate changing educational discourses.

Status - based routing in baggage handling systems : searching verses learning

This study contributes to work in baggage handling system (BHS) control, specifically dynamic bag routing. Although studies in BHS agent-based control have examined the need for intelligent control, but there has not been an effort to explore the dynamic routing problem. As such, this study provides additional insight into how agents can learn to route in a BHS. This study describes a BHS status-based routing algorithm that applies learning methods to select criteria based on routing decisions. Although numerous studies have identified the need for dynamic routing, little analytic attention has been paid to intelligent agents for learning routing tables rather than manual creation of routing rules. We address this issue by demonstrating the ability of agents to learn how to route based on bag status, a robust method that is able to function in a variety of different BHS designs.

Structure-property relationships of nylon 6, MXD6, their blends and nanocomposites

This research project aimed to develop an understanding of the structure-property relationships of nanocomposite materials (injection moulded and fibres) based on nylon 6, MXD6 and their blends, with a layered silicate in combination with polyhedral oligomeric silsesquioxane nanoparticles and SEBS rubber particles.

Use of wild fish and other aquatic organisms as feed in aquaculture; a review of practices and implications in the Asia Pacific

Global and Asian aquaculture have witnessed a ten-fold increase in production from 1980 to 2004. However, the relative percent contribution to production of each of the major commodities has remained almost unchanged. For example, the contribution of freshwater finfish has declined from 71 to 66 percent in Asia but has remained unchanged globally over the last 20 to 30 years. This fact has dictated trends in the use of fish as a feed for cultured stocks. The growth in the sector has gone hand in hand with an increasing dependence on fish as feed, either directly or indirectly. In a number of countries in the Asia-Pacific region, the aquaculture sector has surpassed the capture fisheries sector in its respective contributions to the gross domestic product (GDP). Aquaculture’s increased contribution to national GDPs can be taken as a clear indication of the contribution of the sector to food security and poverty alleviation. The use of finfish and other aquatic organisms as a feed source can be through direct utilization of whole or chopped raw fish in wet form, through fishmeal and fish oil in formulated feeds, and/or as live fish, although the latter is uncommon and the overall amounts used are relatively small. In the first two categories, the fish used are often termed “trash fish/low-value fish”. Although attempts have been made to define this term, all definitions have a certain degree of ambiguity and/or subjectivity. In this regional review, the amount of fish used as feed sources based on the above categories was estimated primarily from the production data, supported by assumptions on the inclusion levels of fishmeal in formulated feeds and observed feed conversion efficiencies for both formulated feeds and for stock fed trash fish/low-value fish directly. A scenario for the use of fish as feed was developed by starting from the levels of aquaculture production recorded in 2004 and assuming increases in production volumes of 10, 15 and 20 percent by 2010, respectively, for the three trajectories. In parallel, the pattern of wild fish use as feed was projected to change as fish and shrimp farmers increasingly replace farmmade feeds by incorporating trash fish/low-value fish with manufactured feeds that include fishmeal. Also, the fishmeal inclusion rates in manufactured feeds are falling slowly, and this has been incorporated into the projections. The regional review also deals with the production of fishmeal using trash fish/low-value fish in the Asia-Pacific region. Regional fishmeal production as a whole is relatively low when compared with that of major fishmeal-producing countries such as Chile, Iceland and Norway, amounting to approximately 1 million tonnes per year. However, there is a trend towards increasing the use of fish industry waste, such as from the tuna canning industry in Thailand. The fishmeal produced in the region is priced considerably lower than globally traded fishmeal, but its quality is poorer. Total fishmeal use in Asian aquaculture in 2004 was estimated as 2 388 million tonnes, the highest proportion of this being used for crustacean aquaculture (1 418 million tonnes). Based on growth predictions (to year 2010) in the sector and improvements to feed quality and management, it is expected that the quantity of fishmeal used in Asian aquaculture will be slightly less than at present. An estimated 240 000 tonnes of fish oil is used in Asian aquaculture, principally in shrimp feeds. Based on production estimates of commodities in 2004 that rely on trash fish/low-value fish as the main feed source, this regional review suggests that Asian aquaculture currently uses between 2 465 and 3 882 million tonnes, an amount that is predicted to decrease to between 1.890 and 2 795 million tonnes by 2010. The use of trash fish/low-value fish and fishmeal by the aquaculture sector has been repeatedly adjudicated as a non-sustainable practice, and globally the sector is seeking to reduce its dependence on fish as feed through improved feed management practices and development of better quality feeds and feed formulations using alternative ingredients. Over the next few years, decreases in the use of trash fish/low-value fish are also expected to be achieved through better conversion of raw materials into fishmeal and fish oil during the reduction processes. The “way forward” in addressing the issue of the use of fish as feed in aquaculture in the Asia-Pacific region includes the need for a concerted regional research thrust to reduce the use of fish as feed sources in aquaculture, as has been achieved in the animal husbandry sector. Secondly, there is a need to increase farmer awareness on the use of trash fish as feed. This is achievable, considering the similar progress that has been made by the region’s shrimp farming sector, which almost exclusively involves small-scale practitioners who are often clustered in a given locality. The analysis also suggests that the use of trash fish/low-value fish in aquaculture may be compatible with improving food security and alleviating poverty. In Asia, trash fish/low-value fish is mostly landed in areas where there are other suitable fish commodities for human consumption. To make the trash fish/low-value fish suitable and available for human consumption would involve some degree of value-adding and transportation costs, which are likely to increase the price to beyond the means of the consumer, particularly in remote rural areas. Under such a scenario, the direct or indirect use of this perishable resource as a feed source to produce a consumable commodity appears to make economic sense and appears to be the most logical use for overall human benefit. In this manner, trash fish/low-value fish contributes to food security by increasing income generation opportunities and hence contributes to poverty alleviation. Another factor that needs to be taken into account is the large numbers of artisanal fishers who harvest this raw material. The continued use of trash fish/low-value fish, therefore, allows these fishers to maintain their livelihoods¹. Admittedly, this is an area that warrants more detailed investigation, from resource use, livelihoods and economic viewpoints.

Thermodynamic and kinetic modelling hydrogenation of titanium particles and sheets

Use of hydrogen as a temporary alloying element in Ti alloys is an attractive approach to improve the mechanical properties of the materials, enhance processability and thereby reduce manufacturing costs. In this paper, the hydrogen diffusion process and the phase transformation both between Ti particles and in Ti sheets were simulated to analyze the mechanism of hydrogen diffusion in different phases (α-Ti, β-Ti and TiHx). With the simulation based on the kinetics and thermodynamics, quantitative behaviors of the hydrogen diffusion and the phase transformation were analyzed. The simulation results provide an insight into the diffusion process and improve the fundamental understanding of the mechanism of diffusion and phase transformation.

Biodegradable Mg-Zr-Ca alloys for bone implant materials

Mg–Zr–Ca alloys were developed for new biodegradable bone implant materials. The microstructure and mechanical property of the Mg–xZr–yCa [x=0·5, 1·0% and y=1·0, 2·0% (wt-% hereafter)] alloys were characterised by optical microscopy, compressive and hardness tests. The in vitro cytotoxicity of the alloys was assessed using osteoblast-like SaOS₂ cells. The corrosion behaviour of these alloys was evaluated by soaking the alloys in simulated body fluid (SBF) and modified minimum essential medium (MMEM). Results indicated that the mechanical properties of the Mg–Zr–Ca are in the range of the mechanical properties of natural bone. The corrosion rate and biocompatibility decreases with the increase in the Ca content in the Mg–Zr–Ca alloys. The solutions of SBF and MMEM with the immersion of the Mg–Zr–Ca alloys show strong alkalisation. The Zr addition to the Mg–Zr–Ca alloys leads to an increase in the corrosion resistance, compressive strength and the ductility of the alloys, and a decrease in the elastic modulus of the Mg–Zr–Ca alloys.

A study of building materials to create an identity of traditional Balinese architecture for urban housing

The use or local architecture characteristics is regulated by the spatial planning and building code of Indonesia. Balinese tmditional architecture has existed, coloured the traditional architecture of Indonesia and can be used as Bali's identity that is different from other regions in Indonesia.On the other hand, the cost of such building is high and most of people in urban areas are unable to afford to build in the traditional architecture style, especially in the residential housing sector .. Some of the major components that determine the price of housing units are the price of land, building materials, labour and technology. In developing countries, the first and second components that affect the unit price of the building are building materials representing about 70% and skilled labour respectively (Ural, 1980). Based on this, a good strategy to adopt in order to minimize the price is to manipulate these two components.Based on a literature review and observation, this study will explain which aspects of building material technology can reduce the building cost and how it can maintain the identity of local architecture.The results of the study indicate that the building material can be created to both reduce cost and adopt traditional architecture style as an identity. The materials have some shapes that can be joined easily to facilitate the skill of the worker and yet still be able to adopt the forms of traditional Balinese architecture.

What factors are associated with adolescents' school break time physical activity and sedentary time?

Purpose Adolescents' physical activity levels during school break time are low and understanding correlates of physical activity and sedentary time in this context is important. This study investigated cross-sectional and longitudinal associations between a range of individual, behavioural, social and policy/organisational correlates and objectively measured school break time physical activity and sedentary time.

Methods In 2006, 146 adolescents (50% males; mean age = 14.1±0.6 years) completed a questionnaire and wore an accelerometer for ≥3 school days. Time spent engaged in sedentary, light (LPA) and moderate-to-vigorous physical activity (MVPA) during school break times (recess and lunchtime) were calculated using existing cut-points. Measures were repeated in 2008 among 111 adolescents. Multilevel models examined cross-sectional and longitudinal associations.

Results Bringing in equipment was cross-sectionally associated with 3.2% more MVPA during break times. Females engaged in 5.1% more sedentary time than males, whilst older adolescents engaged in less MVPA than younger adolescents. Few longitudinal associations were observed. Adolescents who brought sports equipment to school engaged in 7.2% less LPA during break times two years later compared to those who did not bring equipment to school.

Conclusion These data suggest that providing equipment and reducing restrictions on bringing in sports equipment to school may promote physical activity during school recess. Strategies targeting females' and older adolescents', in particular, are warranted.

Regulation to create environments conducive to physical activity : understanding the barriers and facilitators at the Australian State Government level

Introduction Policy and regulatory interventions aimed at creating environments more conducive to physical activity (PA) are an important component of strategies to improve population levels of PA. However, many potentially effective policies are not being broadly implemented. This study sought to identify potential policy/regulatory interventions targeting PA environments, and barriers/facilitators to their implementation at the Australian state/territory government level.

Methods In-depth interviews were conducted with senior representatives from state/territory governments, statutory authorities and non-government organisations (n = 40) to examine participants': 1) suggestions for regulatory interventions to create environments more conducive to PA; 2) support for preselected regulatory interventions derived from a literature review. Thematic and constant comparative analyses were conducted.

Results Policy interventions most commonly suggested by participants fell into two areas: 1) urban planning and provision of infrastructure to promote active travel; 2) discouraging the use of private motorised vehicles. Of the eleven preselected interventions presented to participants, interventions relating to walkability/cycling and PA facilities received greatest support. Interventions involving subsidisation (of public transport, PA-equipment) and the provision of more public transport infrastructure received least support. These were perceived as not economically viable or unlikely to increase PA levels. Dominant barriers were: the powerful ‘road lobby’, weaknesses in the planning system and the cost of potential interventions. Facilitators were: the provision of evidence, collaboration across sectors, and synergies with climate change/environment agendas.

Conclusion This study points to how difficult it will be to achieve policy change when there is a powerful ‘road lobby’ and government investment prioritises road infrastructure over PA-promoting infrastructure. It highlights the pivotal role of the planning and transport sectors in implementing PA-promoting policy, however suggests the need for clearer guidelines and responsibilities for state and local government levels in these areas. Health outcomes need to be given more direct consideration and greater priority within non-health sectors.

Learning from the experts: exploring playground experience and activities using a write and draw technique

Background: Qualitative research into the effect of school recess on children’s physical activity is currently limited. This study used a write and draw technique to explore children’s perceptions of physical activity opportunities during recess.

Methods: 299 children age 7–11 years from 3 primary schools were enlisted. Children were grouped into Years 3 & 4 and Years 5 & 6 and completed a write and draw task focusing on likes and dislikes. Pen profiles were used to analyze the data.

Results: Results indicated ‘likes’ focused on play, positive social interaction, and games across both age groups but showed an increasing dominance of games with an appreciation for being outdoors with age. ‘Dislikes’ focused on dysfunctional interactions linked with bullying, membership, equipment, and conflict for playground space. Football was a dominant feature across both age groups and ‘likes/dislikes’ that caused conflict and dominated the physically active games undertaken.

Conclusion: Recess was important for the development of conflict management and social skills and contributed to physical activity engagement. The findings contradict suggestions that time spent in recess should be reduced because of behavioral issues.

Value relevance of information in hi-tech industries in Australia : accounting information and intangible asset disclosures

The main objective of this study is to test the value relevance of financial and non-financial information in high-tech industries in Australia. Ninety-one companies were selected from the sectors of Pharmaceuticals, Biotechnology and Life Sciences; Technology, Hardware and Equipment; and Telecommunication Services of ASX for the analysis. Both financial and non-financial sections of annual reports were scrutinized in order to obtain data for the analysis. The unaudited sections of annual reports were particularly analysed using NVivo to obtain the word-count of intangible assets. Ohlson’s (1995) Equity Valuation Model (modified for the intangible assets disclosures) was explicitly applied to examine the value relevance of financial and non-financial information. The overall results provide evidence that book value is the most significant factor and earnings are the least significant factor in deciding share prices in high-tech industries in Australia. This finding supports the previous studies that showed value relevance declined in earnings but increased in book value. This research proved that voluntary disclosures of intangible assets are value relevant, providing support for the previous US and Australian studies and the conclusion that investors probably increasingly rely upon alternative information sources.