Application of micro CT and computation modeling in bone tissue engineering

Computer aided technologies, medical imaging, and rapid prototyping has created new possibilities in biomedical engineering. The systematic variation of scaffold architecture as well as the mineralization inside a scaffold/bone construct can be studied using computer imaging technology and CAD/CAM and micro computed tomography (CT). In this paper, the potential of combining these technologies has been exploited in the study of scaffolds and osteochondral repair. Porosity, surface area per unit volume and the degree of interconnectivity were evaluated through imaging and computer aided manipulation of the scaffold scan data. For the osteochondral model, the spatial distribution and the degree of bone regeneration were evaluated. In this study the versatility of two softwares Mimics (Materialize), CTan and 3D realistic visualization (Skyscan) were assessed, too.

Theoretical analysis of the motion and evaporation of exhaled respiratory droplets of mixed composition

The dynamics of droplets exhaled from the respiratory system during coughing or talking is addressed. A mathematical model is presented accounting for the motion of a droplet in conjunction with its evaporation. Droplet evaporation and motion are accounted for under two scenarios: 1) A well mixed droplet and 2) A droplet with inner composition variation. A multiple shells model was implemented to account for internal mass and heat transfer and for concentration and temperature gradients inside the droplet. The trajectories of the droplets are computed for a range of conditions and the spatial distribution and residence times of such droplets are evaluated.

Towards a comprehensive model of driver aggression : a review of the literature and directions for the future

Driver aggression is a road safety issue of growing concern throughout most highly motorised countries, yet to date there is no comprehensive model that deals with this issue in the road safety area. This paper sets out to examine the current state of research and theory on aggressive driving with a view to incorporating useful developments in the area of human aggression from mainstream psychological research. As a first step, evidence regarding the prevalence and incidence of driver aggression, including the impact of the phenomenon on crash rates is reviewed. Inconsistencies in the definition and operationalisation of driver aggression that have hampered research in the area are noted. Existing models of driver aggression are then identified and the need to distinguish and address the role of intentionality as well as the purpose of perpetrating behaviours within both these and research efforts is highlighted. Drawing on recent findings from psychological research into general aggression, it is argued that progress in understanding driver aggression requires models that acknowledge not only the person-related and situational factors, but the cognitive and emotional appraisal processes involved in driver aggression. An effective model is expected to allow the explanation of not only the likelihood and severity of driver aggression behaviours, but also the escalation of incidents within the context of the road environment.

The social work & human services workforce : report from a national study of education, training and workforce needs

This report analyses the national curriculum and workforce needs of the social work and human services workforce. Australia’s community and health services are among the fastest growing sectors of employment in the nation but the sustainability of an appropriately qualified workforce is threatened. Yet there is little integration of education and workforce planning for the community services sector. This contrasts markedly with the health services sector, where key stakeholders are collaboratively addressing workforce challenges. Our research confirmed rapid growth in the social work and human services workforce and it also identified: • an undersupply of professionally qualified social work and human service practitioners to meet workforce demand; • the rapid ageing of the workforce with many workers approaching retirement; • limited career and salary structures creating disincentives to retention; • a highly diverse qualification base across the workforce. This diversity is inconsistent with the specialist knowledge and skills required of practitioners in many domains of community service provision. Our study revealed a lack of co-ordination across VET and higher education to meet the educational needs of the social work and human services workforce. Our analysis identified: • strong representation of equity groups in social work and related human service programs, although further participation of these groups is still needed; • the absence of clear articulation pathways between VET and higher education programs due the absence of co-ordination and planning between these sectors; • substantial variation in the content of the diverse range of social work and human service programs, with accredited programs conforming to national standards and some others in social and behavioural sciences lacking any external validation; • financial obstacles and disincentives to social work and human service practitioners in achieving postgraduate level qualifications. We recommend that: • DEEWR identify accredited social work and human services courses as a national education priority (similar to education and nursing). This will help ensure the supply of professional workers to this sector; • VET and higher education providers are encouraged to collaboratively develop clear and accessible educational pathways across the educational sectors; • DEEWR undertake a national workforce analysis and planning processes in collaboration with CSDMAC, and all social and community services stakeholders, to ensure workforce sustainability; and • COAG develop a national regulation framework for the social and community services workforce. This would provide sound accountability systems, and rigorous practice and educational standards necessary for quality service provision. It will also ensure much needed public confidence in this workforce.

Accumulation of recombinant cellobiohydrolase and endoglucanase in the leaves of mature transgenic sugar cane

A major strategic goal in making ethanol from lignocellulosic biomass a cost-competitive liquid transport fuel is to reduce the cost of production of cellulolytic enzymes that hydrolyse lignocellulosic substrates to fermentable sugars. Current production systems for these enzymes, namely microbes, are not economic. One way to substantially reduce production costs is to express cellulolytic enzymes in plants at levels that are high enough to hydrolyse lignocellulosic biomass. Sugar cane fibre (bagasse) is the most promising lignocellulosic feedstock for conversion to ethanol in the tropics and subtropics. Cellulolytic enzyme production in sugar cane will have a substantial impact on the economics of lignocellulosic ethanol production from bagasse. We therefore generated transgenic sugar cane accumulating three cellulolytic enzymes, fungal cellobiohydrolase I (CBH I), CBH II and bacterial endoglucanase (EG), in leaves using the maize PepC promoter as an alternative to maize Ubi1 for controlling transgene expression. Different subcellular targeting signals were shown to have a substantial impact on the accumulation of these enzymes; the CBHs and EG accumulated to higher levels when fused to a vacuolar-sorting determinant than to an endoplasmic reticulum-retention signal, while EG was produced in the largest amounts when fused to a chloroplast-targeting signal. These results are the first demonstration of the expression and accumulation of recombinant CBH I, CBH II and EG in sugar cane and represent a significant first step towards the optimization of cellulolytic enzyme expression in sugar cane for the economic production of lignocellulosic ethanol.

The textures of globalization : biopolitics and the closure of xenotourism

In this paper, we explore the tensions around a recent controversial development in medical tourism: xenotourism in Mexico. We take this bioendeavor - now ceased - to be emblematic of the global character of contemporary biomedicine, providing insights into the production and operation of scientific knowledge. We explore this through what we call the “textures of globalization”: the anxiety regarding the extent to which Mexico was understood as an (in)appropriate venue for the generation of novel knowledge on xenotransplantation, and as a location for xenotourism. These tensions, which oscillated between calls for individual freedom (choice) and global regulation (standardization), ultimately led to the closure of xenotourism in Mexico.

Ureaplasma colonization of amniotic fluid and efficacy of antenatal corticosteroids for preterm lung maturation in sheep

Objective: To assess the efficacy of maternal betamethasone for improving preterm lung function, in the presence of inflammation induced by amniotic fluid ureaplasma colonization. ----- ----- Study design: Ewes bearing single fetuses were randomized to receive an intra-amniotic injection of Ureaplasma parvum (serovar 6; 2×107 colony forming units) or vehicle at 86±2 days of pregnancy (mean±SD: term is 150d), followed by maternal intramuscular betamethasone (0.5mg/kg) or saline, either 2 or 7 days before delivery of lambs at 123±1d. ----- ----- Results: Amniotic fluid IL-8 was elevated by ureaplasmas (p=0.049) but unaffected by betamethasone. Lung inflammation induced by ureaplasmas was not affected by betamethasone. Lung compliance was increased by ureaplasma colonization (p=0.009) and betamethasone (p=0.042), and effects were additive. Lung surfactant was increased by ureaplasma colonization (p<0.001) and betamethasone 7 days (p=0.001), but not 2 days, before delivery. ----- ----- Conclusion: Inflammation improves preterm lung function due to increases in surfactant. Antenatal corticosteroids further augment lung function, through an apparently independent mechanism.

Depth-dependent biomechanical and biochemical properties of fetal, newborn, and tissue-engineered articular cartilage

Adult articular cartilage has depth-dependent mechanical and biochemical properties which contribute to zone-specific functions. The compressive moduli of immature cartilage and tissue-engineered cartilage are known to be lower than those of adult cartilage. The objective of this study was to determine if such tissues exhibit depth-dependent compressive properties, and how these depth-varying properties were correlated with cell and matrix composition of the tissue. The compressive moduli of fetal and newborn bovine articular cartilage increased with depth (p < 0.05) by a factor of 4-5 from the top 0.1 mm (28 +/- 13 kPa, 141 +/- 10 kPa, respectively) to 1 mm deep into the tissue. Likewise, the glycosaminoglycan and collagen content increased with depth (both p < 0.001), and correlated with the modulus (both p < 0.01). In contrast, tissue-engineered cartilage formed by either layering or mixing cells from the superficial and middle zone of articular cartilage exhibited similarly soft regions at both construct surfaces, as exemplified by large equilibrium strains. The properties of immature cartilage may provide a template for developing tissue-engineered cartilage which aims to repair cartilage defects by recapitulating the natural development and growth processes. These results suggest that while depth-dependent properties may be important to engineer into cartilage constructs, issues other than cell heterogeneity must be addressed to generate such tissues. (c) 2005 Elsevier Ltd. All rights reserved.

A systematic review of environmental factors and obesogenic dietary intakes among adults : are we getting closer to understanding obesogenic environments?

This study examined whether physical, social, cultural and economical environmental factors are associated with obesogenic dietary behaviours and overweight/obesity among adults. Literature searches of databases (i.e. PubMed, CSA Illumina, Web of Science, PsychInfo) identified studies examining environmental factors and the consumption of energy, fat, fibre, fruit, vegetables, sugar-sweetened drinks, meal patterns and weight status. Twenty-eight studies were in-scope, the majority (n= 16) were conducted in the USA. Weight status was consistently associated with the food environment; greater accessibility to supermarkets or less access to takeaway outlets were associated with a lower BMI or prevalence of overweight/obesity. However, obesogenic dietary behaviours did not mirror these associations; mixed associations were found between the environment and obesogenic dietary behaviours. Living in a socioeconomically-deprived area was the only environmental factor consistently associated with a number of obesogenic dietary behaviours. Associations between the environment and weight status are more consistent than that seen between the environment and dietary behaviours. The environment may play an important role in the development of overweight/obesity, however the dietary mechanisms that contribute to this remain unclear and the physical activity environment may also play an important role in weight gain, overweight and obesity.