AITPM Email Newsletter Volume 0910, October 2009 : Presidents Message

President’s Message Hello fellow AITPM members, Well I can’t believe it’s already October! My office is already organising its end of year function and looking to plan for 2010. Our whole School is moving to a different building next year, with the lovely L block eventually making way for a new shiny one. Those of you who have entered the Brisbane CBD from the south side, across the Captain Cook Bridge, would know L block as the big 9 storey brick and concrete Lego block ode to 1970’s functional architecture, which greets you on the right hand side. Onto traffic matters: an issue that has been tossing around in my mind of late is that of speed. I know I am growing older and may be prematurely becoming a “grumpy old man”, but everyone around me locally seems to be accelerating off from the stop line much faster than I was taught to for economical driving, both here and in the United States (yes they made my wife and me resit our written and practical driving tests when we lived there). People here in Australia also seem to be driving right on top of the posted speed limit, on whichever part of the Road Hierarchy, whether urban or rural. I was also taught on both sides of the planet that the posted speed limit is a maximum legal speed, not the recommended driving speed. This message did seem to sink in to the American drivers around me when we lived in Oregon - where people did appear to drive more cautiously. Further, posted speed limits in Oregon were, and I presume still are, set more conservative by about 5mph or 10km/h than Australian limits, for any given part of the Road Hierarchy. Another excellent speed limit treatment used in Oregon was in school zones, where reduced speed limits applied “when children are present” rather than during prescribed hours on school days. This would be especially useful here in Australia, where a lot of extra-curricular activities take place around schools outside of the prescribed speed limit hours. Before and after hours school care is on the increase (with parents dropping and collecting children near dawn and dusk in the winter), and many childcentred land uses are located adjacent to schools, such as Scouts/Guides halls, swimming pools and parks. Consequentially, I believe there needs to be some consideration towards more public campaigning about economical driving and the real purpose of the speed limit = or perhaps even a rethink of the speed limit concept, if people really are driving on top of it and it’s not just me becoming grumpier (our industrial psychology friends at the research centres may be able to assist us here). The Queensland organising committee is now in full swing organising the 2010 AITPM National Conference, What’s New?, so please keep a lookout for related content. Best regards to all, Jon Bunker PS A Cartoonists view of traffic engineers I thought you might enjoy this. http://xkcd.com/277/

AITPM Email Newsletter Volume 0911, November 2009 : President's Message

President’s Report Hello fellow AITPM members, It is interesting to follow the news at present, where transport costs are getting a significant airing. Treasury Secretary Dr Ken Henry has enunciated something Australians may have considered extremely radical just a few years back, but in the present time appears to quite a few to be a realistic alternative. That being a rethink of the way we are charged for using our vehicles. It appears that serious consideration is being given to congestion charging, perhaps in place at least to some extent, of fuel excise. As a transport professional I am pleased that the debate has elevated to the national level, and would look forward that AITPM might contribute appropriately to it. As a motorist though, I naturally have my concerns about being hit in the hip pocket. Not that I actually drive during congested periods very much. I am fortunate to live five minutes either side of two well serviced bus corridors, one of which will eventually become a busway, and work in the central business district, which is hub from all spokes in Brisbane. As such, bus and foot are my preferred commute modes. Ah but I should not gloat, as my smart card fare is about to increase by 20 percent in the New Year! And if the newspapers are to be believed, further substantial increments are proposed over the coming few years. This is reported to recoup some more of the costs of actually providing the quality public transport system that we enjoy in our region. So I expect it will be very interesting to see how transport economics will play out in reality in the coming few years, and how governments cater to Australians who either cannot afford substantial increases in transport costs or have no viable alternatives to those facilities whose costs will increase. The 2010 AITPM National Conference, “What’s New?”, still has the opportunity for authors to submit an abstract for consideration so please consider how you might contribute to the event. Best regards to all, Jon Bunker

Runx2 overexpression in bone marrow stromal cells accelerates bone formation in critically-sized femoral defects

The repair of large non-unions in long bones remains a significant clinical problem due to high failure rates and limited tissue availability for auto- and allografts. Many cell-based strategies for healing bone defects deliver bone marrow stromal cells to the defect site to take advantage of the inherent osteogenic capacity of this cell type. However, many factors, including donor age and ex vivo expansion of the cells, cause bone marrow stromal cells to lose their differentiation ability. To overcome these limitations, we have genetically engineered bone marrow stromal cells to constitutively overexpress the osteoblast specific transcription factor Runx2. In the present study, we examined Runx2-modified bone marrow stromal cells, delivered via poly(caprolactone) scaffolds loaded with type I collagen meshes, in critically-sized segmental defects in rats compared to unmodified cells, cell-free scaffolds and empty defects. Runx2 expression in bone marrow stromal cells accelerated healing of critically-sized defects compared to unmodified bone marrow stromal cells and defects receiving cell-free treatments. These findings provide an accelerated method for healing large bone defects which may reduce recovery time and the need for external fixation of critically-sized defects.

Gifted young adolescents and email : developing a personal language of self

This paper reports on the use of email as a means to access the self-constructions of gifted young adolescents. Australian research shows that gifted young adolescents may feel more lonely and misunderstood than their same-age counterparts, yet they are seldom asked about their lives. Emerging use of online methods as a means of access to individual lives and perceptions has demonstrated the potential offered by the creation of digital texts as narrative data. Details are given of a qualitative study that engaged twelve children aged between 10 and 14 years, who were screened for giftedness, in a project involving the generation of emailed journal entries sent over a period of 6 months. With emphasis on participatory principles, individual young adolescents produced self-managed journal entries that were written and sent to the researcher from personal computers outside the school setting. Drawing from a theoretical understanding of self as constructed within dialogic relationships, the digital setting of email is proposed as a narrative space that fosters healthy self-disclosure. This paper outlines the benefits of using email as a means to explore emotions, promote reflective accounts of self and support the development of a personal language for self-expression. Individual excerpts will be presented to show that the harnessing of personal narratives within an email context has potential to yield valuable insights into the emotions, personal realities and experiences of gifted young adolescents. Findings will be presented to show that the co-construction of self-expressive and explanatory narratives supported by a facilitative adult listener promoted healthy self-awareness amongst participants. This paper contributes to appreciative conversations about using online methods as a flexible and practical avenue for conducting educational research. Furthermore, digital writing in email form will be presented as having distinct advantages over face-to-face methods when utilised with gifted young adolescents who may be unwilling to disclose information within school-based settings.

Application of autologous periosteal cells for the regeneration of class III furcation defects in Beagle dogs

The aim of this study was to evaluate the healing of class III furcation defects following transplantation of autogenous periosteal cells combined with b-tricalcium phosphate (b-TCP). Periosteal cells obtained from Beagle dogs’ periosteum explant cultures, were inoculated onto the surface of b-TCP. Class III furcation defects were created in the mandibular premolars. Three experimental groups were used to test the defects’ healing: group A, b-TCP seeded with periosteal cells were transplanted into the defects; group B, b-TCP alone was used for defect filling; and group C, the defect was without filling materials. Twelve weeks post surgery, the tissue samples were collected for histology, immunohistology and X-ray examination. It was found that both the length of newly formed periodontal ligament and the area of newly formed alveolar bone in group A, were significantly increased compared with both group B and C. Furthermore, both the proportion of newly formed periodontal ligament and newly formed alveolar bone in group A were much higher than those of group B and C. The quantity of cementum and its percentage in the defects (group A) were also significantly higher than those of group C. These results indicate that autogenous periosteal cells combined with b-TCP application can improve periodontal tissue regeneration in class III furcation defects.

Vision-based classification of solder joint defects

Inspection of solder joints has been a critical process in the electronic manufacturing industry to reduce manufacturing cost, improve yield, and ensure product quality and reliability. The solder joint inspection problem is more challenging than many other visual inspections because of the variability in the appearance of solder joints. Although many research works and various techniques have been developed to classify defect in solder joints, these methods have complex systems of illumination for image acquisition and complicated classification algorithms. An important stage of the analysis is to select the right method for the classification. Better inspection technologies are needed to fill the gap between available inspection capabilities and industry systems. This dissertation aims to provide a solution that can overcome some of the limitations of current inspection techniques. This research proposes two inspection steps for automatic solder joint classification system. The “front-end” inspection system includes illumination normalisation, localization and segmentation. The illumination normalisation approach can effectively and efficiently eliminate the effect of uneven illumination while keeping the properties of the processed image. The “back-end” inspection involves the classification of solder joints by using Log Gabor filter and classifier fusion. Five different levels of solder quality with respect to the amount of solder paste have been defined. Log Gabor filter has been demonstrated to achieve high recognition rates and is resistant to misalignment. Further testing demonstrates the advantage of Log Gabor filter over both Discrete Wavelet Transform and Discrete Cosine Transform. Classifier score fusion is analysed for improving recognition rate. Experimental results demonstrate that the proposed system improves performance and robustness in terms of classification rates. This proposed system does not need any special illumination system, and the images are acquired by an ordinary digital camera. In fact, the choice of suitable features allows one to overcome the problem given by the use of non complex illumination systems. The new system proposed in this research can be incorporated in the development of an automated non-contact, non-destructive and low cost solder joint quality inspection system.

Repair of calvarial defects with customized tissue-engineered bone grafts - I. Evaluation of osteogenesis in a three-dimensional culture system

Bone generation by autogenous cell transplantation in combination with a biodegradable scaffold is one of the most promising techniques being developed in craniofacial surgery. The objective of this combined in vitro and in vivo study was to evaluate the morphology and osteogenic differentiation of bone marrow derived mesenchymal progenitor cells and calvarial osteoblasts in a two-dimensional (2-D) and three-dimensional (3-D) culture environment (Part I of this study) and their potential in combination with a biodegradable scaffold to reconstruct critical-size calvarial defects in an autologous animal model [Part II of this study; see Schantz, J.T., et al. Tissue Eng. 2003;9(Suppl. 1):S-127-S-139; this issue]. New Zealand White rabbits were used to isolate osteoblasts from calvarial bone chips and bone marrow stromal cells from iliac crest bone marrow aspirates. Multilineage differentiation potential was evaluated in a 2-D culture setting. After amplification, the cells were seeded within a fibrin matrix into a 3-D polycaprolactone (PCL) scaffold system. The constructs were cultured for up to 3 weeks in vitro and assayed for cell attachment and proliferation using phase-contrast light, confocal laser, and scanning electron microscopy and the MTS cell metabolic assay. Osteogenic differentiation was analyzed by determining the expression of alkaline phosphatase (ALP) and osteocalcin. The bone marrow-derived progenitor cells demonstrated the potential to be induced to the osteogenic, adipogenic, and chondrogenic pathways. In a 3-D environment, cell-seeded PCL scaffolds evaluated by confocal laser microscopy revealed continuous cell proliferation and homogeneous cell distribution within the PCL scaffolds. On osteogenic induction mesenchymal progenitor cells (12 U/L) produce significantly higher (p < 0.05) ALP activity than do osteoblasts (2 U/L); however, no significant differences were found in osteocalcin expression. In conclusion, this study showed that the combination of a mechanically stable synthetic framework (PCL scaffolds) and a biomimetic hydrogel (fibrin glue) provides a potential matrix for bone tissue-engineering applications. Comparison of osteogenic differentiation between the two mesenchymal cell sources revealed a similar pattern.

An electrospun polycaprolactone–collagen membrane for the resurfacing of cartilage defects

A polycaprolactone (PCL)–collagen electrospun mesh is proposed as a novel alternative to the conventional periosteal graft in autologous chondrocyte implantation. This is the first known attempt in designing a cartilage resurfacing membrane using a mechanically resilient PCL mesh with a weight-average molecular weight of 139 300 that is enhanced with bioactive collagen. PCL–collagen 10, 20 and 40% electrospun meshes (Coll-10, Coll-20 and Coll-40) were evaluated and it was discovered that the retention of surface collagen could only be achieved in Coll-20 and Coll-40. Furthermore Coll-20 was stiffer and stronger than Coll-40 and it satisfied the mechanical demands at the cartilage implant site. When seeded with mesenchymal stem cells (MSCs), the cells adhered on the surface of the Coll-20 mesh and they remained viable over a period of 28 days; however, they were unable to infiltrate through the dense meshwork. Cell compatibility was also noted in the chondrogenic environment as the MSCs differentiated into chondrocytes with the expression of Sox9, aggrecan and collagen II. More importantly, the mesh did not induce a hypertrophic response from the cells. The current findings support the use of Coll-20 as a cartilage patch, and future implantation studies are anticipated.

An alginate-based hybrid system for growth factor delivery in the functional repair of large bone defects

The treatment of challenging fractures and large osseous defects presents a formidable problem for orthopaedic surgeons. Tissue engineering/regenerative medicine approaches seek to solve this problem by delivering osteogenic signals within scaffolding biomaterials. In this study, we introduce a hybrid growth factor delivery system that consists of an electrospun nanofiber mesh tube for guiding bone regeneration combined with peptide-modified alginate hydrogel injected inside the tube for sustained growth factor release. We tested the ability of this system to deliver recombinant bone morphogenetic protein-2 (rhBMP-2) for the repair of critically-sized segmental bone defects in a rat model. Longitudinal [mu]-CT analysis and torsional testing provided quantitative assessment of bone regeneration. Our results indicate that the hybrid delivery system resulted in consistent bony bridging of the challenging bone defects. However, in the absence of rhBMP-2, the use of nanofiber mesh tube and alginate did not result in substantial bone formation. Perforations in the nanofiber mesh accelerated the rhBMP-2 mediated bone repair, and resulted in functional restoration of the regenerated bone. [mu]-CT based angiography indicated that perforations did not significantly affect the revascularization of defects, suggesting that some other interaction with the tissue surrounding the defect such as improved infiltration of osteoprogenitor cells contributed to the observed differences in repair. Overall, our results indicate that the hybrid alginate/nanofiber mesh system is a promising growth factor delivery strategy for the repair of challenging bone injuries.

Repair and regeneration of osteochondral defects in the articular joints

People suffering from pain due to osteoarthritic or rheumatoidal changes in the joints are still waiting for a better treatment. Although some studies have achieved success in repairing small cartilage defects, there is no widely accepted method for complete repair of osteochondral defects. Also joint replacements have not yet succeeded in replacing of natural cartilage without complications. Therefore, there is room for a new medical approach, which outperforms currently used methods. The aim of this study is to show potential of using a tissue engineering approach for regeneration of osteochondral defects. The critical review of currently used methods for treatment of osteochondral defects is also provided. In this study, two kinds of hybrid scaffolds developed in Hutmacher's group have been analysed. The first biphasic scaffold consists of fibrin and PCL. The fibrin serves as a cartilage phase while the porous PCL scaffold acts as the subchondral phase. The second system comprises of PCL and PCL-TCP. The scaffolds were fabricated via fused deposition modeling which is a rapid prototyping system. Bone marrow-derived mesenchymal cells were isolated from New Zealand White rabbits, cultured in vitro and seeded into the scaffolds. Bone regenerations of the subchondral phases were quantified via micro CT analysis and the results demonstrated the potential of the porous PCL and PCL-TCP scaffolds in promoting bone healing. Fibrin was found to be lacking in this aspect as it degrades rapidly. On the other hand, the porous PCL scaffold degrades slowly hence it provides an effective mechanical support. This study shows that in the field of cartilage repair or replacement, tissue engineering may have big impact in the future. In vivo bone and cartilage engineering via combining a novel composite, biphasic scaffold technology with a MSC has been shown a high potential in the knee defect regeneration in the animal models. However, the clinical application of tissue engineering requires the future research work due to several problems, such as scaffold design, cellular delivery and implantation strategies.

Evaluation of a hybrid scaffold/cell construct in repair of high-load-bearing osteochondral defects in rabbits

The objective of this study was to evaluate the feasibility and potential of a hybrid scaffold system in large- and high-load-bearing osteochondral defects repair. The implants were made of medical-grade PCL (mPCL) for the bone compartment whereas fibrin glue was used for the cartilage part. Both matrices were seeded with allogenic bone marrow-derived mesenchymal cells (BMSC) and implanted in the defect (4 mm diameter×5 mm depth) on medial femoral condyle of adult New Zealand White rabbits. Empty scaffolds were used at the control side. Cell survival was tracked via fluorescent labeling. The regeneration process was evaluated by several techniques at 3 and 6 months post-implantation. Mature trabecular bone regularly formed in the mPCL scaffold at both 3 and 6 months post-operation. Micro-Computed Tomography showed progression of mineralization from the host–tissue interface towards the inner region of the grafts. At 3 months time point, the specimens showed good cartilage repair. In contrast, the majority of 6 months specimens revealed poor remodeling and fissured integration with host cartilage while other samples could maintain good cartilage appearance. In vivo viability of the transplanted cells was demonstrated for the duration of 5 weeks. The results demonstrated that mPCL scaffold is a potential matrix for osteochondral bone regeneration and that fibrin glue does not inherit the physical properties to allow for cartilage regeneration in a large and high-load-bearing defect site. Keywords: Osteochondral tissue engineering; Scaffold; Bone marrow-derived precursor cells; Fibrin glue

The effect of track defects on the dynamics of wagons under brake-traction torque

Track defects cause profound effects to the stability of railway wagons; normally such problems are modeled for cases of wagons running at constant speed. Brake/traction torque adversely affect the wheel-rail contact characteristics but they are not explicitly considered in most of the wagon-track interaction simulation packages. This research developed a program that can simulate the longitudinal behaviour of railway wagon dynamics under the actions of braking or traction torques. This paper describes the mathematical formulation of modelling of a full wagon system using a fixed coordinate reference system. The effect of both the lateral and the vertical track geometry defects to the dynamics of wagons is reported; sensitivity of traction/brake state is analysed through a series of numerical examples.