Three-dimensional printing of hierarchical and tough mesoporous bioactive glass scaffolds with a controllable pore architecture, excellent mechanical strength and mineralization ability

New-generation biomaterials for bone regenerations should be highly bioactive, resorbable and mechanically strong. Mesoporous bioactive glass (MBG), as a novel bioactive material, has been used for the study of bone regeneration due to its excellent bioactivity, degradation and drug-delivery ability; however, how to construct a 3D MBG scaffold (including other bioactive inorganic scaffolds) for bone regeneration still maintains a significant challenge due to its/their inherit brittleness and low strength. In this brief communication, we reported a new facile method to prepare hierarchical and multifunctional MBG scaffolds with controllable pore architecture, excellent mechanical strength and mineralization ability for bone regeneration application by a modified 3D-printing technique using polyvinylalcohol (PVA), as a binder. The method provides a new way to solve the commonly existing issues for inorganic scaffold materials, for example, uncontrollable pore architecture, low strength, high brittleness and the requirement for the second sintering at high temperature. The obtained 3D-printing MBG scaffolds possess a high mechanical strength which is about 200 times for that of traditional polyurethane foam template-resulted MBG scaffolds. They have highly controllable pore architecture, excellent apatite-mineralization ability and sustained drug-delivery property. Our study indicates that the 3D-printed MBG scaffolds may be an excellent candidate for bone regeneration.

Investigation of electrophoretic loading and enhanced mechanical properties of hydrogels for delivery of therapeutic proteins

Hydrogels, which are three-dimensional crosslinked hydrophilic polymers, have been used and studied widely as vehicles for drug delivery due to their good biocompatibility. Traditional methods to load therapeutic proteins into hydrogels have some disadvantages. Biological activity of drugs or proteins can be compromised during polymerization process or the process of loading protein can be really timeconsuming. Therefore, different loading methods have been investigated. Based on the theory of electrophoresis, an electrochemical gradient can be used to transport proteins into hydrogels. Therefore, an electrophoretic method was used to load protein in this study. Chemically and radiation crosslinked polyacrylamide was used to set up the model to load protein electrophoretically into hydrogels. Different methods to prepare the polymers have been studied and have shown the effect of the crosslinker (bisacrylamide) concentration on the protein loading and release behaviour. The mechanism of protein release from the hydrogels was anomalous diffusion (i.e. the process was non-Fickian). The UV-Vis spectra of proteins before and after reduction show that the bioactivities of proteins after release from hydrogel were maintained. Due to the concern of cytotoxicity of residual monomer in polyacrylamide, poly(2-hydroxyethyl- methacrylate) (pHEMA) was used as the second tested material. In order to control the pore size, a polyethylene glycol (PEG) porogen was introduced to the pHEMA. The hydrogel disintegrated after immersion in water indicating that the swelling forces exceeded the strength of the material. In order to understand the cause of the disintegration, several different conditions of crosslinker concentration and preparation method were studied. However, the disintegration of the hydrogel still occurred after immersion in water principally due to osmotic forces. A hydrogel suitable for drug delivery needs to be biocompatible and also robust. Therefore, an approach to improving the mechanical properties of the porogen-containing pHEMA hydrogel by introduction of an inter-penetrating network (IPN) into the hydrogel system has been researched. A double network was formed by the introduction of further HEMA solution into the system by both electrophoresis and slow diffusion. Raman spectroscopy was used to observe the diffusion of HEMA into the hydrogel prior to further crosslinking by ã-irradiation. The protein loading and release behaviour from the hydrogel showing enhanced mechanical property was also studied. Biocompatibility is a very important factor for the biomedical application of hydrogels. Different hydrogels have been studied on both a three-dimensional HSE model and a HSE wound model for their biocompatibilities. They did not show any detrimental effect to the keratinocyte cells. From the results reported above, these hydrogels show good biocompatibility in both models. Due to the advantage of the hydrogels such as the ability to absorb and deliver protein or drugs, they have potential to be used as topical materials for wound healing or other biomedical applications.

Alone against the crowd: Individual differences in referees' ability to cope under pressure

This paper contributes to the recent debate about the role of referees in the home advantage phenomenon. Specifically, it aims to provide a convincing answer to the newly posed question of the existence of individual differences among referees in terms of the home advantage (Boyko, Boyko, & Boyko, 2007; Johnston, 2008). Using multilevel modelling on a large and representative dataset we find that (1) the home advantage effect differs significantly among referees, and (2) this relationship is moderated by the size of the crowd. These new results suggest that a part of the home advantage is due to the effect of the crowd on the referees, and that some referees are more prone to be influenced by the crowd than others. This provides strong evidence to indicate that referees are a significant contributing factor to the home advantage. The implications of these findings are discussed both in terms of the relevant social psychological research, and with respect to the selection, assessment, and training of referees.

DEM test, visagraph eye movement recordings, and reading ability in children

Purpose. To determine how Developmental Eye Movement (DEM) test results relate to reading eye movement patterns recorded with the Visagraph in visually normal children, and whether DEM results and recorded eye movement patterns relate to standardized reading achievement scores. Methods. Fifty-nine school-age children (age = 9.7 ± 0.6 years) completed the DEM test and had eye movements recorded with the Visagraph III test while reading for comprehension. Monocular visual acuity in each eye and random dot stereoacuity were measured and standardized scores on independently administered reading comprehension tests [reading progress test (RPT)] were obtained. Results. Children with slower DEM horizontal and vertical adjusted times tended to have slower reading rates with the Visagraph (r = -0.547 and -0.414 respectively). Although a significant correlation was also found between the DEM ratio and Visagraph reading rate (r = -0.368), the strength of the relationship was less than that between DEM horizontal adjusted time and reading rate. DEM outcome scores were not significantly associated with RPT scores. When the relative contribution of reading ability (RPT) and DEM scores was accounted for in multivariate analysis, DEM outcomes were not significantly associated with Visagraph reading rate. RPT scores were associated with Visagraph outcomes of duration of fixations (r = -0.403) and calculated reading rate (r = 0.366) but not with DEM outcomes. Conclusions.DEM outcomes can identify children whose Visagraph recorded eye movement patterns show slow reading rates. However, when reading ability is accounted for, DEM outcomes are a poor predictor of reading rate. Visagraph outcomes of duration of fixation and reading rate relate to standardized reading achievement scores; however, DEM results do not. Copyright © 2011 American Academy of Optometry.

An exploration of young students' ability to generalise function tasks

The Early Years Generalising Project involves Australian students, Years 1-4 (age 5-9), and explores how the students grasp and express generalisations. This paper focuses on the data collected from clinical interviews with Year 3 and 4 cohorts in an investigative study focusing on the identifications, prediction and justification of function rules. It reports on students' attempts to generalise from function machine contexts, describing the various ways students express generalisation and highlighting the different levels of justification given by students. Finally, we conjecture that there are a set of stages in the expression and justification of generalisations that assist students to reach generality within tasks.

Older drivers’ insight into their hazard perception ability

Even though the driving ability of older adults may decline with age, there is evidence that some individuals attempt to compensate for these declines using strategies such as restricting their driving exposure. Such compensatory mechanisms rely on drivers’ ability to evaluate their own driving performance. This paper focuses on one key aspect of driver ability that is associated with crash risk and has been found to decline with age: hazard perception. Three hundred and seven drivers, aged 65 to 96, completed a validated video-based hazard perception test. There was no significant relationship between hazard perception test response latencies and drivers’ ratings of their hazard perception test performance, suggesting that their ability to assess their own test performance was poor. Also, age related declines in hazard perception latency were not reflected in drivers’ self-ratings. Nonetheless, ratings of test performance were associated with self-reported regulation of driving, as was self-rated driving ability. These findings are consistent with the proposal that, while self-assessments of driving ability may be used by drivers to determine the degree to which they restrict their driving, the problem is that drivers have little insight into their own driving ability. This may impact on the potential road safety benefits of self-restriction of driving because drivers may not have the information needed to optimally self-restrict. Strategies for addressing this problem are discussed.

Information Behavior: A Socio-Cognitive Ability

Abstract: How has human information behavior evolved? Our paper explores this question in the form of notions, models and theories about the relationship between information behavior and human evolution. Alexander’s Ecological Dominance and Social Competition/Cooperation (EDSC) model currently provides the most comprehensive overview of human traits in the development of a theory of human evolution and sociality. His model provides a basis for explaining the evolution of human socio-cognitive abilities, including ecological dominance, and social competition/cooperation. Our paper examines the human trait of information behavior as a socio-cognitive ability related to ecological dominance, and social competition/cooperation. The paper first outlines what is meant by information behavior from various interdisciplinary perspectives. We propose that information behavior is a socio-cognitive ability that is related to and enables other sociocognitive abilities such as human ecological dominance, and social competition/cooperation. The paper reviews the current state of evolutionary approaches to information behavior and future directions for this research . Keywords: information behavior, socio-cognitive ability, ecological dominance, social competition, social cooperation.

The role of physical activity in the lives of people with lymphoedema following cancer treatment : a social constructionist study

Lymphoedema is a chronic condition predominantly affecting the limbs, although it can involve the trunk and other areas of the body. It is characterised by swelling due to excess accumulation of fluid in body tissues. Secondary lymphoedema, which arises following cancer treatment, is the more common form of lymphoedema in developed countries. At least 20% of those diagnosed with the most common cancers will develop lymphoedema. This is a concern in Australia as incidence of these cancers is increasing. Cancer survival rates are also increasing. Currently, this equates to 9 300 new cases of secondary lymphoedema diagnosed each year. Considerable physical and psychosocial impacts of lymphoedema have been reported and its subsequent impact on health-related quality of life can exacerbate other side effects of cancer treatment. Exercise following cancer treatment has been shown to significantly reduce the impact of treatment side effects, improve quality of life and physical status. While participating in exercise does not increase risk nor exacerbate existing lymphoedema, reductions in incidence of lymphoedema exacerbations and associated symptoms have been observed in women participating in regular weight lifting following breast cancer treatment. Despite these benefits, lymphoedema prevention and management advice cautions people with lymphoedema against „repetitive use. or „overuse. of their affected arm. It is possible that this advice creates a barrier to participation in physical activity; however, little is known about the relationship between physical activity and lymphoedema. In addition, the majority of studies examining the experiences of people living with lymphoedema and the impact of the condition have been predominantly conducted internationally and have focused on women following breast cancer. This study sought to explore firstly, how men and women construct their experience of living with lymphoedema following treatment for a range of cancers in the context of everyday life in Australia; and secondly, to analyse the role of physical activity in the lives of those living with lymphoedema following cancer treatment. A social constructivist grounded theory approach was taken to explore these objectives as it is acknowledged that human actions and the meanings associated with these actions are influenced by the interaction between the self and the social world. It is also acknowledged that the research process itself is a social construction between the researcher and participant. Purposive sampling techniques were used to recruit a total of 29 participants from a variety of sources. Telephone interviews and focus groups were conducted to collect data. Data were concurrently collected and analysed and analysis was conducted using the constant comparative method. The core category that developed in objective one was „sense of self‟. The self was defined by perceptions participants held of themselves and their identity prior to a lymphoedema diagnosis and changes to their perceptions and identity since diagnosis. Three conceptual categories which related to each other and to „sense of self‟ were developed through the process of coding that represented the process of how participants constructed their experiences living with secondary lymphoedema in the context of everyday life. Firstly, altered normalcy reflected the physical and psychosocial changes experienced and the effect it had on their lives. Secondly, „accidental journey‟ reflected participants‟ journey with the heath care system prior to diagnosis through to longer term management. Thirdly, renegotiating control revealed participants perceived control over lymphoedema and their ability to participate in daily activities previously enjoyed. These findings revealed the failure of the broader health system to recognise the significant and chronic nature of a lymphoedema diagnosis following cancer treatment with greater understanding, knowledge and support from health professionals being needed. The findings also reveal access to health professionals trained in lymphoedema management, a comprehensive approach encompassing both physical and psychosocial needs and provision of practical and meaningful guidelines supported by scientific evidence would contribute to improved treatment and management of the condition. The key findings for objective two were that people with lymphoedema define physical activity in different ways. Physical activity post-diagnosis was perceived as important by most for a variety of reasons ranging from everyday functioning, to physical and psychosocial health benefits. Issues relating to the impact of lymphoedema on physical activity related to the impact on peoples‟ ability to be physically active, confusion about acceptable forms of physical activity and barriers that lymphoedema presented to being physically active. A relationship between how people construct their experiences with lymphoedema and the role of physical activity was also established. The contribution of physical activity to the lives of people living with lymphoedema following cancer treatment appeared to be influenced by their sense of self as socially constructed through their experiences prior to diagnosis and following diagnosis with lymphoedema. The influence of pre-lymphoedema habits, norms and beliefs suggests the importance of effective health promotion messages to encourage physical activity among the general population and specific messages and guidelines particular to the needs of those diagnosed with lymphoedema following cancer treatment. The influence of participant.s social constructions on the lymphoedema experience highlights the importance of improving interactions between the overall health care system and patients, providing a clear treatment plan, providing evidence-based and clear advice about participation in appropriate physical activity, which in doing so will limit the physical and psychosocial effect of lymphoedema and providing comprehensive physical and psychosocial support to those living with the condition and their families. This study has contributed to a deep understanding of people.s experiences with lymphoedema following cancer treatment and the role of physical activity in the context of daily life in Australia. Findings from this study lead to recommendations for advocacy, a comprehensive approach to diagnosis, treatment and management, and specific areas for future research.

Even moderate visual impairments degrade drivers’ ability to see pedestrians at night

Purpose: To determine the effect of moderate levels of refractive blur and simulated cataracts on nighttime pedestrian conspicuity in the presence and absence of headlamp glare. Methods: The ability to recognize pedestrians at night was measured in 28 young adults (M=27.6 years) under three visual conditions: normal vision, refractive blur and simulated cataracts; mean acuity was 20/40 or better in all conditions. Pedestrian recognition distances were recorded while participants drove an instrumented vehicle along a closed road course at night. Pedestrians wore one of three clothing conditions and oncoming headlamps were present for 16 participants and absent for 12 participants. Results: Simulated visual impairment and glare significantly reduced the frequency with which drivers recognized pedestrians and the distance at which the drivers first recognized them. Simulated cataracts were significantly more disruptive than blur even though photopic visual acuity levels were matched. With normal vision, drivers responded to pedestrians at 3.6x and 5.5x longer distances on average than for the blur or cataract conditions, respectively. Even in the presence of visual impairment and glare, pedestrians were recognized more often and at longer distances when they wore a “biological motion” reflective clothing configuration than when they wore a reflective vest or black clothing. Conclusions: Drivers’ ability to recognize pedestrians at night is degraded by common visual impairments even when the drivers’ mean visual acuity meets licensing requirements. To maximize drivers’ ability to see pedestrians, drivers should wear their optimum optical correction, and cataract surgery should be performed early enough to avoid potentially dangerous reductions in visual performance.

The relationship between chronic disease self-efficacy and nutritional status, functional ability and quality of life in older adults at risk of hospital readmission

Background and significance: Older adults with chronic diseases are at increasing risk of hospital admission and readmission. Approximately 75% of adults have at least one chronic condition, and the odds of developing a chronic condition increases with age. Chronic diseases consume about 70% of the total Australian health expenditure, and about 59% of hospital events for chronic conditions are potentially preventable. These figures have brought to light the importance of the management of chronic disease among the growing older population. Many studies have endeavoured to develop effective chronic disease management programs by applying social cognitive theory. However, limited studies have focused on chronic disease self-management in older adults at high risk of hospital readmission. Moreover, although the majority of studies have covered wide and valuable outcome measures, there is scant evidence on examining the fundamental health outcomes such as nutritional status, functional status and health-related quality of life. Aim: The aim of this research was to test social cognitive theory in relation to self-efficacy in managing chronic disease and three health outcomes, namely nutritional status, functional status, and health-related quality of life, in older adults at high risk of hospital readmission. Methods: A cross-sectional study design was employed for this research. Three studies were undertaken. Study One examined the nutritional status and validation of a nutritional screening tool; Study Two explored the relationships between participants. characteristics, self-efficacy beliefs, and health outcomes based on the study.s hypothesized model; Study Three tested a theoretical model based on social cognitive theory, which examines potential mechanisms of the mediation effects of social support and self-efficacy beliefs. One hundred and fifty-seven patients aged 65 years and older with a medical admission and at least one risk factor for readmission were recruited. Data were collected from medical records on demographics, medical history, and from self-report questionnaires. The nutrition data were collected by two registered nurses. For Study One, a contingency table and the kappa statistic was used to determine the validity of the Malnutrition Screening Tool. In Study Two, standard multiple regression, hierarchical multiple regression and logistic regression were undertaken to determine the significant influential predictors for the three health outcome measures. For Study Three, a structural equation modelling approach was taken to test the hypothesized self-efficacy model. Results: The findings of Study One suggested that a high prevalence of malnutrition continues to be a concern in older adults as the prevalence of malnutrition was 20.6% according to the Subjective Global Assessment. Additionally, the findings confirmed that the Malnutrition Screening Tool is a valid nutritional screening tool for hospitalized older adults at risk of readmission when compared to the Subjective Global Assessment with high sensitivity (94%), and specificity (89%) and substantial agreement between these two methods (k = .74, p < .001; 95% CI .62-.86). Analysis data for Study Two found that depressive symptoms and perceived social support were the two strongest influential factors for self-efficacy in managing chronic disease in a hierarchical multiple regression. Results of multivariable regression models suggested advancing age, depressive symptoms and less tangible support were three important predictors for malnutrition. In terms of functional status, a standard regression model found that social support was the strongest predictor for the Instrumental Activities of Daily Living, followed by self-efficacy in managing chronic disease. The results of standard multiple regression revealed that the number of hospital readmission risk factors adversely affected the physical component score, while depressive symptoms and self-efficacy beliefs were two significant predictors for the mental component score. In Study Three, the results of the structural equation modelling found that self-efficacy partially mediated the effect of health characteristics and depression on health-related quality of life. The health characteristics had strong direct effects on functional status and body mass index. The results also indicated that social support partially mediated the relationship between health characteristics and functional status. With regard to the joint effects of social support and self-efficacy, social support fully mediated the effect of health characteristics on self-efficacy, and self-efficacy partially mediated the effect of social support on functional status and health-related quality of life. The results also demonstrated that the models fitted the data well with relative high variance explained by the models, implying the hypothesized constructs under discussion were highly relevant, and hence the application for social cognitive theory in this context was supported. Conclusion: This thesis highlights the applicability of social cognitive theory on chronic disease self-management in older adults at risk of hospital readmission. Further studies are recommended to validate and continue to extend the development of social cognitive theory on chronic disease self-management in older adults to improve their nutritional and functional status, and health-related quality of life.