Assimilating cell sheets and hybrid scaffolds for dermal tissue engineering

Cell sheets can be used to produce neo-tissue with mature extracellular matrix. However, extensive contraction of cell sheets remains a problem. We devised a technique to overcome this problem and applied it to tissue engineer a dermal construct. Human dermal fibroblasts were cultured with poly(lactic-co-glycolic acid)-collagen meshes and collagen-hyaluronic acid foams. Resulting cell sheets were folded over the scaffolds to form dermal constructs. Human keratinocytes were cultured on these dermal constructs to assess their ability to support bilayered skin regeneration. Dermal constructs produced with collagen-hyaluronic acid foams showed minimal contraction, while those with poly(lactic-co-glycolic acid)-collagen meshes curled up. Cell proliferation and metabolic activity profiles were characterized with PicoGreen and AlamarBlue assays, respectively. Fluorescent labeling showed high cell viability and F-actin expression within the constructs. Collagen deposition was detected by immunocytochemistry and electron microscopy. Transforming Growth Factor-alpha and beta1, Keratinocyte Growth Factor and Vascular Endothelial Growth Factor were produced at various stages of culture, measured by RT-PCR and ELISA. These results indicated that assimilating cell sheets with mechanically stable scaffolds could produce viable dermal-like constructs that do not contract. Repeated enzymatic treatment cycles for cell expansion is unnecessary, while the issue of poor cell seeding efficiency in scaffolds is eliminated.

Talking the talk and walking the walk : how managers can influence the quality of work-life balance in a construction project

Purpose – The construction industry in Australia is characterised by a long work-hours culture, with conditions that make it difficult for staff to balance their work and non-work lives. The objective of this paper is to measure the success of a work-place intervention designed to improve work-life balance (WLB) in an alliance project in the construction industry, and the role the project manager plays in this success. Design/methodology/approach – The paper focuses on an alliance case study. Interviews were conducted at two points in time, several months apart, after the interventions were implemented. Findings – Results showed that staff on the whole were more satisfied with their work experience after the interventions, and indicated the important role that managers' attitudes and behaviours played. Originality/value – Managerial support for work-life initiatives is a critical element in achieving WLB and satisfaction with working arrangements. The fact that the manager “talked the talk and walked the walk” was a major contributing success factor, which has not previously been demonstrated.

Strengthening of circular hollow steel tubular sections using high modulus CFRP sheets

This paper describes the behaviour of very high strength (VHS) circular steel tubes strengthened by carbon fibre reinforced polymer (CFRP) and subjected to axial tension. A series of tests were conducted with different bond lengths and number of layers. The distribution of strain through the thickness of CFRP layers and along CFRP bond length was studied. The strain was found to generally decrease along the CFRP bond length far from the joint. The strain through the thickness of the CFRP layers was also found to decrease from bottom to top layer. The effective bond length for high modulus CFRP was established. Finally empirical models were developed to estimate the maximum load for a given CFRP arrangement.

An extended measure of work-life balance culture : development and confirmation of the measure

This paper extends the work of Thompson, Beauvais and Lyness (1999) to develop a more comprehensive measure of work-life balance culture. Thompson et al. developed a survey based on three sub-dimensions which examine work-family culture. We have extended this to incorporate extra dimensions, and to broaden the measure to encompass life aspects beyond the family. Two studies were conducted in order to test and refine the measure. Over 700 participants in the first study completed the survey, and the Confirmatory Factor Analysis results show that the extended measure is robust. Further, a second study with a sample of 629 participants confirmed the general measure, with slight adaptations. The results are discussed in relation to the use of the measure for work-life balance research.

Postural balance under normal and altered sensory conditions in normal-weight and overweight children

Background Little or no research has been done in the overweight child on the relative contribution of multisensory information to maintain postural stability. Therefore, the purpose of this study was to investigate postural balance control under normal and experimentally altered sensory conditions in normal-weight versus overweight children. Methods Sixty children were stratified into a younger (7–9 yr) and an older age group (10–12 yr). Participants were also classified as normal-weight (n = 22) or overweight (n = 38), according to the international BMI cut-off points for children. Postural stability was assessed during quiet bilateral stance in four sensory conditions (eyes open or closed, normal or reduced plantar sensation), using a Kistler force plate to quantify COP dynamics. Coefficients of variation were calculated as well to describe intra-individual variability. Findings Removal of vision resulted in systematically higher amounts of postural sway, but no significant BMI group differences were demonstrated across sensory conditions. However, under normal conditions lower plantar cutaneous sensation was associated with higher COP velocities and maximal excursion of the COP in the medial-lateral direction for the overweight group. Regardless of condition, higher variability was shown in the overweight children within the 7–9 yr old subgroup for postural sway velocity, and more specifically medial–lateral velocity. Interpretation In spite of these subtle differences, results did not establish any clear underlying sensory organization impairments that may affect standing balance performance in overweight children compared to normal-weight peers. Consequently, it is believed that other factors account for overweight children's functional balance deficiencies.

Role demands and work-family balance experience in Malaysia : the different moderating effects of collectivism and gender role identity among diverse ethnic groups

The purpose of this thesis is to examine the influence of ethnic cultural values on the relationship of role demands and the work-family balance (WFB) experience. Past studies have found that the demands from work and family roles have a different impact on the work-family experience in people of different ethnicity. Researchers attribute these results to the cultural differences across the groups. However, there has been no empirical support for these assumptions because most past studies did not explicitly measure the cultural dimension in their design. Therefore, although studies have found ethnic differences in work-family experience, as cultural variables were not measured, it cannot be determined whether these differences were due to the differing ethnic groups’ cultural styles. The present thesis is set up to address this limitation in the literature, employing the Malay and Chinese ethnic groups in Malaysia as the study samples. The investigation consisted of pilot interviews and two survey studies. The interviews were carried out to establish the perception of WFB by target participants of a non-western nation. The first survey served to identify whether the Malay and Chinese ethnic groups residing under the same economic and social systems vary in their perceptions of work and family roles. The second survey tests the research model empirically, that is, whether cultural values moderate the relationship between role demands and WFB and if these moderation effects vary across ethnic groups. From the interviews, the results indicated that work-family experience is not a universal experience, but is partly culture-specific. Specifically, in the case of Malaysia, WFB is very much observed from the role obligation perspective. In particular, balance is perceived when work duties and household affairs are both adequately fulfilled. On the other hand, the conceptualisation of WFB in terms of role satisfaction and role interference also emerged in the interviews, suggesting the universality of these constructs across cultures. The findings from Survey One indicated that participants of different ethnicities in this study do not differ greatly in their perceptions regarding their participation in work and family roles. Generally, these participants revealed the less traditional attitudes towards women’s participation in work and family roles. However, variations were observed between the two groups in terms of reasons for working, spouses’ preferences towards their employment, and the extent to which their work role is perceived to impede their normative role performance in the household. Despite these differences, the Malay and Chinese ethnic groups showed more similarities than differences in their perceptions of work and family. The findings from Survey Two, which tested the research model, produced mixed results. On the whole, the results showed that the cultural dimensions examined in this study (i.e. collectivism, work identity and family identity) did influence the relationship between role demands and WFB experience, thus providing empirical evidence for the assumption in the literature that the relationship between role demand and work-family experience is moderated by cultural values. Most importantly, support was found for the proposition that these moderation effects vary between the Malay and Chinese ethnic groups. Moreover, this study also found evidence that Malays and Chinese differ significantly on collectivism and work identity cultural dimensions where Malays are found to be more collectivist than the Chinese, while work identity is stronger in the Chinese than in the Malays. There is no difference in the levels of family identity between the two groups. Of all the three moderators, work identity was deemed the most important because many of the supported hypotheses pertained to the work identity moderating effects. In contrast, family identity does not seem to have much moderating influence on role demand-WFB relationships, while the results for the collectivism moderator are mixed. As such, although not conclusive, it can be deduced that variations in the effects of role demand on work-family experience across ethnicity are a result of the groups’ cultural differences, thereby supporting the assumption in the literature.

Graphene-like nano-sheets for surface acoustic wave gas sensor applications

The gas sensing properties of graphene-like nano-sheets deposited on 36° YX lithium tantalate (LiTaO3) surface acoustic wave (SAW) transducers are reported. The thin graphene-like nano-sheets were produced via the reduction of graphite oxide which was deposited on SAW interdigitated transducers (IDTs). Their sensing performance was assessed towards hydrogen (H2) and carbon monoxide (CO) in a synthetic air carrier gas at room temperature (25 °C) and 40 °C. Raman and X-ray photoelectron spectroscopy (XPS) revealed that the deposited graphite oxide (GO) was not completely reduced creating small, graphitic nanocrystals ∼2.7 nm in size. © 2008 Elsevier B.V.

Hybrid light-emitting diodes based on flexible sheets of mass-produced ZnO nanowires

We report the production of free-standing thin sheets made up of mass-produced ZnO nanowires and the application of these nanowire sheets for the fabrication of ZnO/organic hybrid light-emitting diodes in the manner of assembly. Different p-type organic semiconductors are used to form heterojunctions with the ZnO nanowire film. Electroluminescence measurements of the devices show UV and visible emissions. Identical strong red emission is observed independent of the organic semiconductor materials used in this work. The visible emissions corresponding to the electron transition between defect levels within the energy bandgap of ZnO are discussed.

The role of life friendly policies on employees’ work-life balance

Employees' inability to balance work and non-work related responsibilities have resulted in an increase in stress related illnesses. Historically, research into the relationship between work and non-work has primarily focused on work/family conflict, predominately investigating the impact of this conflict on parents, usually mothers. To date research has not sufficiently examined the management practices that enable all 'individuals' to achieve a 'balance' between work and life. This study explores the relationship between contemporary life friendly HR management policies and work/life balance for individuals as well as the effect of managerial support to the policies. Self-report questionnaire data from 1,241 men and women is analysed and discussed to enable organizations to consider the use of life friendly policies and thus create a convergence between the well-being of employees and the effectiveness of the organization.

Pre-clinical evaluation of amphiphilic silicone oligomers for scar remediation

The formation of hypertrophic scars is a frequent outcome of wound repair and often requires further therapy with treatments such as silicone gel sheets (SGS; Perkins et al., 1983). Although widely used, knowledge regarding SGS and their mechanism of action on hypertrophic scars is limited. Furthermore, SGS require consistent application for at least twelve hours a day for up to twelve consecutive months, beginning as soon as wound reepithelialisation has occurred. Preliminary research at QUT has shown that some species of silicone present in SGS have the ability to permeate into collagen gel skin mimetics upon exposure. An analogue of these species, GP226, was found to decrease both collagen synthesis and the total amount of collagen present following exposure to cultures of cells derived from hypertrophic scars. This silicone of interest was a crude mixture of silicone species, which resolved into five fractions of different molecular weight. These five fractions were found to have differing effects on collagen synthesis and cell viability following exposure to fibroblasts derived from hypertrophic scars (HSF), keloid scars (KF) and normal skin (nHSF and nKF). The research performed herein continues to further assess the potential of GP226 and its fractions for scar remediation by determining in more detail its effects on HSF, KF, nHSF, nKF and human keratinocytes (HK) in terms of cell viability and proliferation at various time points. Through these studies it was revealed that Fraction IV was the most active fraction as it induced a reduction in cell viability and proliferation most similar to that observed with GP226. Cells undergoing apoptosis were also detected in HSF cultures exposed to GP226 and Fraction IV using the Tunel assay (Roche). These investigations were difficult to pursue further as the fractionation process used for GP226 was labour-intensive and time inefficient. Therefore a number of silicones with similar structure to Fraction IV were synthesised and screened for their effect following application to HSF and nHSF. PDMS7-g-PEG7, a silicone-PEG copolymer of low molecular weight and low hydrophilic-lipophilic balance factor, was found to be the most effective at reducing cell proliferation and inducing apoptosis in cultures of HSF, nHSF and HK. Further studies investigated gene expression through microarray and superarray techniques and demonstrated that many genes are differentially expressed in HSF following treatment with GP226, Fraction IV and PDMS7-g-PEG7. In brief, it was demonstrated that genes for TGFβ1 and TNF are not differentially regulated while genes for AIFM2, IL8, NSMAF, SMAD7, TRAF3 and IGF2R show increased expression (>1.8 fold change) following treatment with PDMS7-g-PEG7. In addition, genes for αSMA, TRAF2, COL1A1 and COL3A1 have decreased expression (>-1.8 fold change) following treatment with GP226, Fraction IV and PDMS7-g-PEG7. The data obtained suggest that many different pathways related to apoptosis and collagen synthesis are affected in HSF following exposure to PDMS7-g-PEG7. The significance is that silicone-PEG copolymers, such as GP226, Fraction IV and PDMS7-g-PEG7, could potentially be a non-invasive substitute to apoptosis-inducing chemical agents that are currently used as scar treatments. It is anticipated that these findings will ultimately contribute to the development of a novel scar therapy with faster action and improved outcomes for patients suffering from hypertrophic scars.