Direct writing of chitosan scaffolds using a robotic system

Purpose – This paper aims to present a novel rapid prototyping (RP) fabrication methods and preliminary characterization for chitosan scaffolds. Design – A desktop rapid prototyping robot dispensing (RPBOD) system has been developed to fabricate scaffolds for tissue engineering (TE) applications. The system is a computer-controlled four-axis machine with a multiple-dispenser head. Neutralization of the acetic acid by the sodium hydroxide results in a precipitate to form a gel-like chitosan strand. The scaffold properties were characterized by scanning electron microscopy, porosity calculation and compression test. An example of fabrication of a freeform hydrogel scaffold is demonstrated. The required geometric data for the freeform scaffold were obtained from CT-scan images and the dispensing path control data were converted form its volume model. The applications of the scaffolds are discussed based on its potential for TE. Findings – It is shown that the RPBOD system can be interfaced with imaging techniques and computational modeling to produce scaffolds which can be customized in overall size and shape allowing tissue-engineered grafts to be tailored to specific applications or even for individual patients. Research limitations/implications – Important challenges for further research are the incorporation of growth factors, as well as cell seeding into the 3D dispensing plotting materials. Improvements regarding the mechanical properties of the scaffolds are also necessary. Originality/value – One of the important aspects of TE is the design scaffolds. For customized TE, it is essential to be able to fabricate 3D scaffolds of various geometric shapes, in order to repair tissue defects. RP or solid free-form fabrication techniques hold great promise for designing 3D customized scaffolds; yet traditional cell-seeding techniques may not provide enough cell mass for larger constructs. This paper presents a novel attempt to fabricate 3D scaffolds, using hydrogels which in the future can be combined with cells.

A spectroscopic comparison of selected Chinese kaolinite, coal bearing kaolinite and halloysite : a mid-infrared and near-infrared study

Mid-infrared (MIR) and near-infrared (NIR) spectroscopy have been compared and evaluated for differentiating kaolinite, coal bearing kaolinite and halloysite. Kaolinite, coal bearing kaolinite and halloysite are the three relative abundant mineral of the kaolin group, especially in China. In the MIR spectra, the differences are shown in the 3000-3600 cm-1 between kaolinite and halloysite. It can not be obviously differentiated the kaolinite and halloysite, let alone kaolinite and coal bearing kaolinite. However, NIR, together with MIR, give us the sufficient evidence to differentiate the kaolinite and halloysite, especially kaolinite and coal bearing kaolinite. There are obvious differences between kaolinite and halloysite in the all range of their spectra, and it also show some difference between kaolinite and coal bearing kaolinite. Therefore, the reproducibility of measurement, signal to noise ratio and richness of qualitative information should be simultaneously considered for proper selection of a spectroscopic method for mineral analysis.

Social interactions in Chinese parks : a walk in Lu Xun Park

What can we learn from Chinese parks and Chinese people? We took a walk through Lu Xun Park, one of Shanghai’s most popular parks. Here hundreds of people participate in dozens of physical and mental exercises that are considered to be essential for good health and fitness. We found that the most successful spaces for social interaction and inclusiveness were not just coded for ‘doing’ a diverse range of activities but also for ‘showing’ those activities. This dual role of park spaces could be given greater design consideration in encouraging occupants of small households in Australia to make greater use of public parks in the future.

Writing stories to enhance scientific literacy

In response to international concerns about scientific literacy and students’ waning interest in school science, this study investigated the effects of a science-writing project about the socioscientific issue of biosecurity on the development of students’ scientific literacy. Students generated two BioStories each that merged scientific information with the narrative storylines in the project. The study was conducted in two phases. In the exploratory phase, a qualitative case study of a 6th grade class involving classroom observations and interviews informed the design of the second, confirmatory phase of the study, which was conducted at a different school. This phase involved a mixed methods approach featuring a quasi-experimental design with two classes of Australian middle school students (i.e., 6th grade, 11 years of age, n=55). The results support the argument that writing the sequence of stories helped the students become more familiar with biosecurity issues, develop a deeper understanding of related biological concepts, and improve their interest in science. On the basis of these findings, teachers should be encouraged to engage their students in the practice of writing about socioscientific issues (SSI) in a way that integrates scientific information into narrative storylines. Extending the practice to older students, and exploring additional issues related to writing about SSI are recommended for further research.

Provincialising Perth? Satellite television and the Chinese communities in Western Australia

This paper explores the tensions between the security that access to satellite television programming from mainland China lends its 'new migrants' (xin yimin) and the vulnerability the consumption of 'foreign' media leaves them open to in Perth. The indiscreet 2-3 metre satellite dishes are an increasingly common sight in Perth's suburban backyards and on first glance, their presence might be (mis)interpreted as attempts to turn Perth into the China's next province. However, it is our argument these attempts to manage multiple belongings can be better understood within a context of conditions. These include Perth's geographical and metaphoric distance from the metropolitan centres of Sydney and Melbourne; the intense media scrutiny of China in recent times; the rapid closeness and synchronicity between China and Perth for reasons of trade, the dynamics of China's media environment and the mainland Chinese's care for and regard for themselves as mobile, global citizens of contemporary society.