Bioactive inorganic materials/alginate composite microspheres with controllable drug-delivery ability

Alginate microspheres are considered a promising material as a drug carrier in bone repair due to excellent biocompatibility, but their main disadvantage is low drug entrapment efficiency and non-controllable release. The aim of this study was to investigate the effect of incorporating mesoporous bioglass (MBG), non-mesoporous bioglass (BG) or hydroxyapatite (HAp) into alginate microspheres on their drug-loading and release properties. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and atomic emission spectroscopy (AES) were used to analyse the composition, structure and dissolution of bioactive inorganic materials and their microspheres. Dexamethasone (DEX)-loading and release ability of four microspheres were tested in phosphate buffered saline with varying pHs. Results showed that the drug-loading capacity was enhanced with the incorporation of bioactive inorganic materials into alginate microspheres. The MBG/Alginate microspheres had the highest drug loading ability. DEX release from alginate microspheres correlated to the dissolution of MBG, BG and HAp in PBS, and that the pH was an efficient factor in controlling the DEX release; a high pH resulted in greater DEX release, whereas a low pH delayed DEX release. In addition, MBG/alginate, BG/alginate and HAp/alginate microspheres had varying apatite-formation and dissolution abilities, which indicate that the composites would behave differently with respect to bioactivity. The study suggests that microspheres made of a composite of bioactive inorganic materials and alginate have a bioactivity and degradation profile which greatly improves their drug delivery capacity, thus enhancing their potential applications as bioactive filler materials for bone tissue regeneration.

Use of advanced technology videotapes in the delivery of structual engineering courses

A teaching and learning development project is currently under way at Queensland University of Technology to develop advanced technology videotapes for use with the delivery of structural engineering courses. These tapes consist of integrated computer and laboratory simulations of important concepts, and behaviour of structures and their components for a number of structural engineering subjects. They will be used as part of the regular lectures and thus will not only improve the quality of lectures and learning environment, but also will be able to replace the ever-dwindling laboratory teaching in these subjects. The use of these videotapes, developed using advanced computer graphics, data visualization and video technologies, will enrich the learning process of the current diverse engineering student body. This paper presents the details of this new method, the methodology used, the results and evaluation in relation to one of the structural engineering subjects, steel structures.

A collaborative approach to home care delivery for older clients: Perspectives of home care providers

A collaborative approach to home care (HC) delivery for older clients has taken centre stage (Nies, 2006). In Finland, public home help and home health care services have been combined to form the home care unit, whose goal is to provide a collaborative approach to care delivery through cooperation and sharing of responsibilities. In this model, the general practitioner (GP), home care nurses (HCN) and home help workers (HHW) care for shared clients. GPs and HCNs provide health care, such as monitoring of clients’ health status, and HHWs assist with personal care tasks such as dressing, washing and meal preparation. As the needs of older clients are multiple, collaboration is needed as one professional group cannot take sole responsibility (Nies, 2006). This paper reports on a study undertaken to examine home care unit care providers’ perspectives of the collaborative approach to HC delivery for older clients.

Evaluation of risk factors leading to cost overrun in delivery of highway construction projects

Accurate owner budget estimates are critical to the initial decision-to-build process for highway construction projects. However, transportation projects have historically experienced significant construction cost overruns from the time the decision to build has been taken by the owner. This paper addresses the problem of why highway projects overrun their predicted costs. It identifies the owner risk variables that contribute to significant cost overrun and then uses factor analysis, expert elicitation, and the nominal group technique to establish groups of importance ranked owner risks. Stepwise multivariate regression analysis is also used to investigate any correlation of the percentage of cost overrun with risks, together with attributes such as highway project type, indexed cost, geographics location, and project delivery method. The research results indicate a correlation between the reciprocal of project budgets size and percentage cost overrun. This can be useful for owners in determining more realistic decision-to-build highway budget estimates by taking into account the economies of scale associated with larger projects.

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.

Novel PCL-based honeycomb scaffolds as drug delivery systems for rhBMP-2

This study investigated a novel drug delivery system (DDS), consisting of polycaprolactone (PCL) or polycaprolactone 20% tricalcium phosphate (PCL-TCP) biodegradable scaffolds, fibrin Tisseel sealant and recombinant bone morphogenetic protein-2 (rhBMP-2) for bone regeneration. PCL and PCL-TCP-fibrin composites displayed a loading efficiency of 70% and 43%, respectively. Fluorescence and scanning electron microscopy revealed sparse clumps of rhBMP-2 particles, non-uniformly distributed on the rods’ surface of PCL-fibrin composites. In contrast, individual rhBMP-2 particles were evident and uniformly distributed on the rods’ surface of the PCL-TCP-fibrin composites. PCL-fibrin composites loaded with 10 and 20 μg/ml rhBMP-2 demonstrated a triphasic release profile as quantified by an enzyme-linked immunosorbent assay (ELISA). This consisted of burst releases at 2 h, and days 7 and 16. A biphasic release profile was observed for PCL-TCP-fibrin composites loaded with 10 μg/ml rhBMP-2, consisting of burst releases at 2 h and day 14. PCL-TCP-fibrin composites loaded with 20 μg/ml rhBMP-2 showed a tri-phasic release profile, consisting of burst releases at 2 h, and days 10 and 21. We conclude that the addition of TCP caused a delay in rhBMP-2 release. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and alkaline phosphatase assay verified the stability and bioactivity of eluted rhBMP-2 at all time points

Determinants of infant and young child feeding practices in Nepal : secondary data analysis of demographic and health survey 2006

Background: Childhood undernutrition and mortality are high in Nepal, and therefore interventions on infant and young child feeding practices deserve high priority. Objective. To estimate infant and young child feeding indicators and the determinants of selected feeding practices. Methods: The sample consisted of 1,906 children aged 0 to 23 months from the Demographic and Health Survey 2006. Selected indicators were examined against a set of variables using univariate and multivariate analyses. Results. Breastfeeding was initiated within the first hour after birth in 35.4% of children, 99.5% were ever breastfed, 98.1% were currently breastfed, and 3.5% were bottle-fed. The rate of exclusive breastfeeding among infants under 6 months of age was 53.1%, and the rate of timely complementary feeding among those 6 to 9 months of age was 74.7%. Mothers who made antenatal clinic visits were at a higher risk for no exclusive breastfeeding than those who made no visits. Mothers who lived in the mountains were more likely to initiate breastfeeding within 1 hour after birth and to introduce complementary feeding at 6 to 9 months of age, but less likely to exclusively breastfeed. Cesarean deliveries were associated with delay in timely initiation of breastfeeding. Higher rates of complementary feeding at 6 to 9 months were also associated with mothers with better education and those above 35 years of age. Risk factors for bottle-feeding included living in urban areas and births attended by trained health personnel. Conclusions: Most breastfeeding indicators in Nepal are below the expected levels to achieve a substantial reduction in child mortality. Breastfeeding promotion strategies should specifically target mothers who have more contact with the health care delivery system, while programs targeting the entire community should be continued.

Across-country comparisons of selected infant and young child feeding indicators and associated factors in four South Asian countries

Background: Information on infant and young child feeding is widely available in Demographic and Health Surveys and National Family Health Surveys for countries in South Asia; however, infant and young child feeding indicators from these surveys have not been compared between countries in the region. Objective. To compare the key indicators of breastfeeding and complementary feeding and their determinants in children under 24 months of age between four South Asian countries. Methods: We selected data sets from the Bangladesh Demographic and Health Survey 2004, the India National Family Health Survey (NFHS-03) 2005–06, the Nepal Demographic and Health Survey 2006, and the Sri Lanka 2000 Demographic and Health Survey. Infant feeding indicators were estimated according to the key World Health Organization indicators. Results: Exclusive breastfeeding rates were 42.5% in Bangladesh, 46.4% in India, and 53.1% in Nepal. The rate of full breastfeeding ranged between 60.6% and 73.9%. There were no factors consistently associated with the rate of no exclusive breastfeeding across countries. Utilization of health services (more antenatal clinic visits) was associated with higher rates of exclusive breastfeeding in India but lower rates in Nepal. Delivery at a health facility was a negative determinant of exclusive breastfeeding in India. Postnatal contacts by Public Health Midwives were a positive factor in Sri Lanka. A considerable proportion of infants under 6 months of age had been given plain water, juices, or other nonmilk liquids. The rate of timely first suckling ranged from 23.5% in India to 56.3% in Sri Lanka. Delivery by cesarean section was found to be a consistent negative factor that delayed initiation of breastfeeding. Nepal reported the lowest bottle-feeding rate of 3.5%. Socioeconomically privileged mothers were found to have higher bottlefeeding rates in most countries. Conclusions: Infant and young child feeding practices in the South Asia region have not reached the expected levels that are required to achieve a substantial reduction in child mortality. The countries with lower rates of exclusive breastfeeding have a great potential to improve the rates by preventing infants from receiving water and water-based or other nonmilk liquids during the first 6 months of life.

Online service delivery models : an international comparison in the public sector

Governments around the world are facing the challenge of responding to increased expectations by their customers with regard to public service delivery. Citizens, for example, expect governments to provide better and more efficient electronic services on the Web in an integrated way. Online portals have become the approach of choice in online service delivery to meet these requirements and become more customer-focussed. This study describes and analyses existing variants of online service delivery models based upon an empirical study and provides valuable insights for researchers and practitioners in government. For this study, we have conducted interviews with senior management representatives from five international governments. Based on our findings, we distinguish three different classes of service delivery models. We describe and characterise each of these models in detail and provide an in-depth discussion of the strengths and weaknesses of these approaches.

Comparing cost uplift in infrastructure delivery methods : a case based approach

The alliance project delivery method is used for approximately one third of all Australian government infrastructure projects representing $8-$10 billion per annum. Despite its widespread use, little is known about the differences between estimated project cost and actual cost over the project lifecycle. This paper presents the findings of research into 14 Australian government alliance case studies investigating the observed cost uplift over each project’s lifecycle. I find that significant cost uplift is likely and that this uplift is greater than that afflicting traditional delivery methods. Furthermore, most of the cost uplift occurs at a different place in the project lifecycle, namely between Business Case and Contractual Commitment.