Characteristics of a two-layer microstrip patch antenna for Bluetooth applications

A double-layer rectangular patch microstrip antenna suitable for Bluetooth applications is investigated. The patch is etched on a separate substrate which is suspended above the ground plane and supported by an MCX connector. The air gap between the patch and the ground plane increases the impedance bandwidth and can be used to tune the resonant frequency. This paper presents experimental results on the effects of various parameters on the antenna characteristics and provides guidelines for the design of such an antenna.

Microstrip decoupling networks for low-order multi-port arrays with reduced element spacing

An array of monopole elements with reduced element spacing of λ/6 to λ/20 is considered for application in digital beam-forming and direction-finding. The small element spacing introduces strong mutual coupling between the array elements. This paper discusses that decoupling can be achieved analytically for arrays with three elements and describes Kuroda’s identities to realize the lumped elements of the derived decoupling network. Design procedures and equations are proposed. Experimental results are presented. The decoupled array has a bandwidth of 1% and a superdirective radiation pattern.

A superdirective 3-element array for adaptive beamforming

A small array composed of three monopole elements with very small element spacing on the order of λ/6 to λ/20 is considered for application in adaptive beamforming. The properties of this 3-port array are governed by strong mutual coupling. It is shown that for signal-to-noise maximization, it is not sufficient to adjust the weights to compensate for the effects of mutual coupling. The necessity for a RF-decoupling network (RF-DN) and its simple realization are shown. The array with closely spaced elements together with the RF-DN represents a superdirective antenna with a directivity of more than 10 dBi. It is shown that the required fractional frequency bandwidth and the available unloaded Q of the antenna and RF-DN structure determine the lower limit for the element spacing.

Photocatalytic disinfection of bacterial pollutants using suspended and immobilized TiO(2) powders

The photocatalytic disinfection of Enterobacter cloacae and Enterobacter coli using microwave (MW), convection hydrothermal (HT) and Degussa P25 titania was investigated in suspension and immobilized reactors. In suspension reactors, MW-treated TiO(2) was the most efficient catalyst (per unit weight of catalyst) for the disinfection of E. cloacae. However, HT-treated TiO(2) was approximately 10 times more efficient than MW or P25 titania for the disinfection of E. coli suspensions in surface water using the immobilized reactor. In immobilized experiments, using surface water a significant amount of photolysis was observed using the MW- and HT-treated films; however, disinfection on P25 films was primarily attributed to photocatalysis. Competitive action of inorganic ions and humic substances for hydroxyl radicals during photocatalytic experiments, as well as humic substances physically screening the cells from UV and hydroxyl radical attack resulted in low rates of disinfection. A decrease in colony size (from 1.5 to 0.3 mm) was noted during photocatalytic experiments. The smaller than average colonies were thought to occur during sublethal (•) OH and O(2) (•-) attack. Catalyst fouling was observed following experiments in surface water and the ability to regenerate the surface was demonstrated using photocatalytic degradation of oxalic acid as a model test system

Extreme science and engineering : a higher education widening participation initiative at QUT

The QUT Extreme Science and Engineering program provides free hands-on workshops to schools, presented by scientists and engineers to students from prep to year 12 in their own classrooms. The workshops are tied to the school curriculum and give students access to professional quality instruments, helping to stimulate their interest in science and engineering, with the aim of generating a greater take up of STEM related subjects in the senior high school years. In addition to engaging students in activities, workshop presenters provide role models of both genders, helping to breakdown preconceived ideas of the type of person who becomes a scientist or engineer and demystifying the university experience. The Extreme Science and Engineering vans have been running for 10 years and as such demonstrate a sustainable and reproducible model for schools engagement. With funding provided through QUT’s Widening Participation Equity initiative (HEPPP funded) the vans which averaged 120 school visits each year has increased to 150+ visits in 2010. Additionally 100+ workshops (hands-on and career focused) have been presented to students from low socio-economic status schools, on the three QUT campuses in 2011. While this is designed as a long-term initiative the short term results have been very promising, with 3000 students attending the workshops in the first six months and teacher and students feedback has been overwhelmingly positive.

Implementing a systematic process for rapidly embedding sustainability within chemical engineering education: a case study of James Cook University, Australia

Sustainability has emerged as a primary context for engineering education in the 21st Century, particularly the sub-discipline of chemical engineering. However, there is confusion over how to go about integrating sustainability knowledge and skills systemically within bachelor degrees. This paper addresses this challenge, using a case study of an Australian chemical engineering degree to highlight important practical considerations for embedding sustainability at the core of the curriculum. The paper begins with context for considering a systematic process for rapid curriculum renewal. The authors then summarise a 2-year federally funded project, which comprised piloting a model for rapid curriculum renewal led by the chemical engineering staff. Model elements contributing to the renewal of this engineering degree and described in this paper include: industry outreach; staff professional development; attribute identification and alignment; program mapping; and curriculum and teaching resource development. Personal reflections on the progress and process of rapid curriculum renewal in sustainability by the authors and participating engineering staff will be presented as a means to discuss and identify methodological improvements, as well as highlight barriers to project implementation. It is hoped that this paper will provide an example of a formalised methodology on which program reform and curriculum renewal for sustainability can be built upon in other higher education institutions.

An investigation into the effect of amphiphilic siloxane oligomers on dermal fibroblasts

This study investigates the effect of well-defined poly(dimethylsiloxane)-poly(ethylene glycol) (PDMS-PEG) ABA linear block co-oligomers on the proliferation of human dermal fibroblasts. The co-oligomers assessed ranged in molecular weight (MW) from 1335 to 5208 Da and hydrophilic-lipophilic balance (HLB) from 5.9 to 16.6 by varying the number of both PDMS and PEG units. In general, it was found that co-oligomers of low MW or intermediate hydrophilicity significantly reduced fibroblast proliferation. A linear relationship between down-regulation of fibroblast proliferation, and the ratio HLB/MW was observed at concentrations of 0.1 and 1.0 wt % of the oligomers. This enabled the structures with highest efficiency to be determined. These results suggest the possible use of the PEG-PDMS-PEG block co-oligomers as an alternative to silicone gels for hypertrophic scar remediation.

Globalization of science education : comment and a commentary

The globalized nature of modern society has generated a number of pressures that impact internationally on countries’ policies and practices of science education. Among these pressures are key issues of health and environment confronting global science, global economic control through multinational capitalism, comparative and competitive international testing of student science achievement, and the desire for more humane and secure international society. These are not all one-way pressures and there is evidence of both more conformity in the intentions and practices of science education and of a greater appreciation of how cultural differences, and the needs of students as future citizens can be met. Hence while a case for economic and competitive subservience of science education can be made, the evidence for such narrowing is countered by new initiatives that seek to broaden its vision and practices. The research community of science education has certainly widened internationally and this generates many healthy exchanges, although cultural styles of education other than Western ones are still insufficiently recognized. The dominance of English language within these research exchanges is, however, causing as many problems as it solves. Science education, like education as a whole, is a strongly cultural phenomenon, and this provides a healthy and robust buffer to the more negative effects of globalization

Biological responses of human bone marrow mesenchymal stem cells to Sr-M-Si (M = Zn, Mg) silicate bioceramics

Strontium (Sr), Zinc (Zn), magnesium (Mg), and silicon (Si) are reported to be essential trace elements for the growth and mineralization of bone. We speculated that the combination of these bioactive elements in bioceramics may be effective to regulate the osteogenic property of boneforming cells. In this study, two Sr-containing silicate bioceramics, Sr2ZnSi2O7 (SZS) and Sr2MgSi2O7 (SMS), were prepared. The biological response of human bone marrow mesenchymal stem cells (BMSCs) to the two bioceramics (in the forms of powders and dense ceramic bulks) was systematically studied. In powder form, the effect of powder extracts on the viability and alkaline phosphatase (ALP) activity of BMSCs was investigated. In ceramic disc form, both direct and indirect coculture of BMSCs with ceramic discs were used to investigate their biological response, including attachment, proliferation, ALP activity, and bone-related genes expression. Beta-tricalcium phosphate (b-TCP) and akermanite (Ca2MgSi2O7, CMS) were used as control materials. The results showed that the Sr, Zn, and Si (or Sr, Mg, and Si)-containing ionic products from SZS and SMS powders enhanced ALP activity of BMSCs, compared to those from b-TCP. Both SZS and SMS ceramic discs supported the growth of BMSCs, and most importantly, significantly enhanced the ALP activity and bone-related genes expression of BMSCs as compared to b-TCP. The results suggest that the specific combination of bioactive ions (Sr, Zn, Si, e.g.) in bioceramics is a viable way to improve the biological performance of biomaterials, and the form of materials and surface properties were nonnegligible factors to influence cell response.

Strontium-containing mesoporous bioactive glass scaffolds with improved osteogenic/cementogenic differentiation of periodontal ligament cells for periodontal tissue engineering

To achieve the ultimate goal of periodontal tissue engineering, it is of great importance to develop bioactive scaffolds which could stimulate the osteogenic/cementogenic differentiation of periodontal ligament cells (PDLCs) for the favorable regeneration of alveolar bone, root cementum, and periodontal ligament. Strontium (Sr) and Sr-containing biomaterials have been found to induce osteoblast activity. However, there is no systematic report about the interaction between Sr or Sr-containing biomaterials and PDLCs for periodontal tissue engineering. The aims of this study were to prepare Sr-containing mesoporous bioactive glass (Sr-MBG) scaffolds and investigate whether the addition of Sr could stimulate the osteogenic/cementogenic differentiation of PDLCs in tissue engineering scaffold system. The composition, microstructure and mesopore properties (specific surface area, nano-pore volume and nano-pore distribution) of Sr-MBG scaffolds were characterized. The proliferation, alkaline phosphatase (ALP) activity and osteogenesis/cementogenesis-related gene expression (ALP, Runx2, Col I, OPN and CEMP1) of PDLCs on different kinds of Sr-MBG scaffolds were systematically investigated. The results show that Sr plays an important role in influencing the mesoporous structure of MBG scaffolds in which high contents of Sr decreased the well-ordered mesopores as well as their surface area/pore volume. Sr2+ ions could be released from Sr-MBG scaffolds in a controlled way. The incorporation of Sr into MBG scaffolds has significantly stimulated ALP activity and osteogenesis/cementogenesis-related gene expression of PDLCs. Furthermore, Sr-MBG scaffolds in simulated body fluids environment still maintained excellent apatite-mineralization ability. The study suggests that the incorporation of Sr into MBG scaffolds is a viable way to stimulate the biological response of PDLCs. Sr-MBG scaffolds are a promising bioactive material for periodontal tissue engineering application.

Sustainable development as a meta-context for engineering education

At the end of the first decade of the twenty-first century, there is unprecedented awareness of the need for a transformation in development, to meet the needs of the present while also preserving the ability of future generations to meet their own needs. However, within engineering, educators still tend to regard such development as an ‘aspect’ of engineering rather than an overarching meta-context, with ad hoc and highly variable references to topics. Furthermore, within a milieu of interpretations there can appear to be conflicting needs for achieving sustainable development, which can be confusing for students and educators alike. Different articulations of sustainable development can create dilemmas around conflicting needs for designers and researchers, at the level of specific designs and (sub-) disciplinary analysis. Hence sustainability issues need to be addressed at a meta-level using a whole of system approach, so that decisions regarding these dilemmas can be made. With this appreciation, and in light of curriculum renewal challenges that also exist in engineering education, this paper considers how educators might take the next step to move from sustainable development being an interesting ‘aspect’ of the curriculum, to sustainable development as a meta-context for curriculum renewal. It is concluded that capacity building for such strategic considerations is critical in engineering education.

Engineering of vascularized adipose constructs

Adipose tissue engineering offers a promising alternative to the current surgical techniques for the treatment of soft tissue defects. It is a challenge to find the appropriate scaffold that not only represents a suitable environment for cells but also allows fabrication of customized tissue constructs, particularly in breast surgery. We investigated two different scaffolds for their potential use in adipose tissue regeneration. Sponge-like polyurethane scaffolds were prepared by mold casting with methylal as foaming agent, whereas polycaprolactone scaffolds with highly regular stacked-fiber architecture were fabricated with fused deposition modeling. Both scaffold types were seeded with human adipose tissuederived precursor cells, cultured and implanted in nude mice using a femoral arteriovenous flow-through vessel loop for angiogenesis. In vitro, cells attached to both scaffolds and differentiated into adipocytes. In vivo, angiogenesis and adipose tissue formation were observed throughout both constructs after 2 and 4 weeks, with angiogenesis being comparable in seeded and unseeded constructs. Fibrous tissue formation and adipogenesis were more pronounced on polyurethane foam scaffolds than on polycaprolactone prototyped scaffolds. In conclusion, both scaffold designs can be effectively used for adipose tissue engineering.