Long-term effects of hydrogel properties on human chondrocyte behavior

Hydrogels provide a 3-dimensional network for embedded cells and offer promise for cartilage tissue engineering applications. Nature-derived hydrogels, including alginate, have been shown to enhance the chondrocyte phenotype but are variable and not entirely controllable. Synthetic hydrogels, including polyethylene glycol (PEG)-based matrices, have the advantage of repeatability and modularity; mechanical stiffness, cell adhesion, and degradability can be altered independently. In this study, we compared the long-term in vitro effects of different hydrogels (alginate and Factor XIIIa-cross-linked MMP-sensitive PEG at two stiffness levels) on the behavior of expanded human chondrocytes and the development of construct properties. Monolayer-expanded human chondrocytes remained viable throughout culture, but morphology varied greatly in different hydrogels. Chondrocytes were characteristically round in alginate but mostly spread in PEG gels at both concentrations. Chondrogenic gene (COL2A1, aggrecan) expression increased in all hydrogels, but alginate constructs had much higher expression levels of these genes (up to 90-fold for COL2A1), as well as proteoglycan 4, a functional marker of the superficial zone. Also, chondrocytes expressed COL1A1 and COL10A1, indicative of de-differentiation and hypertrophy. After 12 weeks, constructs with lower polymer content were stiffer than similar constructs with higher polymer content, with the highest compressive modulus measured in 2.5% PEG gels. Different materials and polymer concentrations have markedly different potency to affect chondrocyte behavior. While synthetic hydrogels offer many advantages over natural materials such as alginate, they must be further optimized to elicit desired chondrocyte responses for use as cartilage models and for development of functional tissue-engineered articular cartilage.

Assessment reform and educational change in Australia

This chapter addresses the changing climate of assessment policy and practice in Australia in response to global trends in education and the mounting accountability demands of standards-driven reform. Queensland, a State of Australia, has a tradition of respecting and trusting teacher judgment through the practice of, and policy commitment to, externally moderated school-based assessment. This chapter outlines the global trends in curriculum and assessment reform, and then analyzes the impact of international comparisons on national policy. The creation of the Australian Curriculum, Assessment and Reporting Authority (ACARA) together with the intent of establishing a standards-referenced framework raises tensions and challenges for teachers’ practice. The argument for sustaining confidence in teacher-based assessment is developed with reference to research evidence pertaining to the use of more authentic assessments and moderation practices for the purposes of improving learning, equity and accountability. Evidence is drawn from local studies of teacher judgment practice and used to demonstrate these developments and in so doing illuminate the complex issues of engaging the demands of policy while sustaining confidence in teacher assessment.

Introducing action research as a vehicle to bring about change to a psychiatric nursing curriculum in Taiwan

The focus of this study is on curriculum change within a School of Nursing in Taiwan where there is a growing demand for educational reform in order to meet the new accreditation standards and demands of the Taiwan Nursing Accreditation Council (TNAC). The aim of this study was to transform the Psychiatric Nursing curriculum in ways that are empowering, generative and sustainable. This study introduced Action Research as a vehicle to bring about curriculum transformation. I conceptualised a framework to guide the transformation process based on the notions of learner-centredness, conceptual change, pedagogical knowledge, reflection, collaboration, reculturing and empowerment. The Action Plan was developed in accordance with the conceptual framework, and was developed in five steps through which team members explored and became aware of our conceptions of teaching and learning, and then planned and implemented actions to change our curriculum, and examined and reflected on the curriculum transformation. The study demonstrated the value of working collaboratively to solve educational problems. This study also suggested that experiential knowledge, when shared and integrated with theoretical knowledge, can constructively contribute to all aspects of curriculum transformation. This study further supported the value of including clinical facilitators in the development and transformation of curricula. It confirmed that academics and clinical facilitators can work together to create new learning for students. This study is significant for both practical and political reasons. Its practical significance lies in its direct utility to the learners and teachers who were involved in the study. The political significance lies in the potential of the study to lead to further changes or improvements in other, similar contexts. The study is limited in that any interpretations cannot be generalised to other contexts. However, what emerged adds to the body of knowledge in such a way that it would constitute the basis for better informed educational practice.

Diversity in action : minority group media and social change

This audio magazine, written by Melissa Giles, features three Brisbane-based media organisations: Radio 4RPH, Queensland Pride and 98.9FM. [#1 - INTRODUCTION - read by Sara Cowling]----- [#2 - RADIO 4RPH: SHARING THE WORD - read by Ellen-Maree Elliot (and Sara Cowling)]----- [#3 - QUEENSLAND PRIDE: OUT IN THE STREET - read by Dominique Wiehahn (and Sara Cowling)]----- [#4 - 98.9FM: BREAKING THE MOULD - read by Paige Ross (and Sara Cowling)]----- [#5 - CONCLUSION - read by Sara Cowling]

The impact of school connectedness on violent behavior, transport risk taking behavior and associated injuries in adolescence

Adolescents engage in many risk-taking behaviors that have the potential to lead to injury. The school environment has a significant role in shaping adolescent behavior, and this study aimed to provide additional information about the benefits associated with connectedness to school. Early adolescents aged 13 to 15 years (N = 509, 49% boys) were surveyed about school connectedness, engagement in transport and violence risk-taking, and injury experiences. Significant relations were found between school connectedness and reduced engagement in both transport and violence risk-taking, as well as fewer associated injuries. This study has implications for the area of risk-taking and injury prevention, as it suggests the potential for reducing adolescents' injury through school based interventions targeting school connectedness.

Freeway traffic oscillations : microscopic analysis of formations and propagations using Wavelet Transform

In this paper we identify the origins of stop-and-go (or slow-and-go) driving and measure microscopic features of their propagations by analyzing vehicle trajectories via Wavelet Transform. Based on 53 oscillation cases analyzed, we find that oscillations can be originated by either lane-changing maneuvers (LCMs) or car-following behavior (CF). LCMs were predominantly responsible for oscillation formations in the absence of considerable horizontal or vertical curves, whereas oscillations formed spontaneously near roadside work on an uphill segment. Regardless of the trigger, the features of oscillation propagations were similar in terms of propagation speed, oscillation duration, and amplitude. All observed cases initially exhibited a precursor phase, in which slow-and-go motions were localized. Some of them eventually transitioned into a well developed phase, in which oscillations propagated upstream in queue. LCMs were primarily responsible for the transition, although some transitions occurred without LCMs. Our findings also suggest that an oscillation has a regressive effect on car following behavior: a deceleration wave of an oscillation affects a timid driver (with larger response time and minimum spacing) to become less timid and an aggressive driver less aggressive, although this change may be short-lived. An extended framework of Newell’s CF is able to describe the regressive effects with two additional parameters with reasonable accuracy, as verified using vehicle trajectory data.

From the bottom-up : redesigning the international legal response to anthropogenic climate change

The design of the Kyoto Protocol renders it incapable of effectively responding to the problem of anthropogenic climate change. Therefore, this article explores the opportunity to construct a new, principled legal approach to respond to climate change that is premised on nationally derived legal responses. To do so, this article considers the theoretical foundation of the international legal response to climate change – Hardin's "The Tragedy of the Commons‟ – and the systemic design faults of the Kyoto Protocol. This article also suggests four principles – a judicious mix of legal instruments, flexibility, intrinsic legal coherence, and quantifiable and achievable targets for the reduction of greenhouse gas intensity – that are necessary to guide the creation of a nationally derived legal response to climate change. This approach is intended to provide the catalyst for new bilateral and multilateral arrangements that can, with the passing of time, generate sufficient momentum to drive the creation of a new and effective cooperative international legal framework to mitigate anthropogenic climate change.

Thermal behavior and decomposition of kaolinite-potassium acetate intercalation composite

A series of kaolinite-potassium acetate intercalation composite was prepared. The thermal behavior and decomposition of these composites were investigated by simultaneous differential scanning calorimetry-thermogravimetric analysis (DSC-TGA), X-ray diffraction (XRD) and Fourier-transformation infrared (FT-IR). The XRD pattern at room temperature indicated that intercalation of potassium acetate into kaolinite causes an increase of the basal spacing from 0.718 to 1.428nm. The peak intensity of the expanded phase of the composite decreased with heating above 300°C, and the basal spacing reduced to 1.19nm at 350°C and 0.718nm at 400°C. These were supported by DSC-TGA and FT-IR measurements, where the endothermic reactions are observed between 300 and 600°C. These reactions can be divided into two stages: 1) Removal of the intercalated molecules between 300-400°C. 2) Dehydroxylation of kaolinite between 400-600°C. Significant changes were observed in the infrared bands assigned to outer surface hydroxyl, inner surface hydroxyl, inner hydroxyl and hydrogen bands.

Legislative change will impact on conveyancing

One of the more significant conveyancing decisions of 2005 was MNM Developments Pty Ltd v Gerrard [2005] QCA 230 (‘Gerrard’). Real estate agents, in particular, became concerned when the Court of Appeal raised grave doubts concerning the validity of a contract for the sale of residential property formed by the use of fax. As a result, the government acted quickly to introduce amendments to the Property Agents and Motor Dealers Act 2000 (Qld) (‘PAMDA’) and the Body Corporate and Community Management Act 1997 (Qld) (‘BCCMA’). The relevant Act is the Liquor and Other Acts Amendment Act 2005 (Qld). These amendments commenced on 1 December 2005. In the second reading speech, the Minister stated that these amendments would provide certainty for sellers of residential properties or their agents when transmitting pre-contractual documents by facsimile and other electronic means. The accuracy of this prediction must be assessed in light of the errors that may occur.