Interfacial debonding behavior of composite beam/plates with PZT patch

This paper studies interfacial debonding behavior of composite beams which include piezoelectric materials, adhesive and host beam. The focus is put on crack initiation and growth of the piezoelectric adhesive interface. Closed-form solutions of interface stresses and energy release rates are obtained for adhesive layer in the piezoelectric composite beams. Finite element analyses have been carried out to study the initiation and growth of interfaces crack for piezoelectric beams with interface element by ANSYS, in which the interface element of FE model is based on the cohesive zone models to characterize the fracture behavior of the interfacial debonding. The results have been compared with analystical solution, and the influence of different geometry and material parameters on the interfacial behavior of piezoelectric composite beams have been discussed.

Mechanical Behavior of Articular Cartilage After Osteochondral Autograft Transfer in an Ovine Model

BACKGROUND: Grafting of autologous hyaline cartilage and bone for articular cartilage repair is a well-accepted technique. Although encouraging midterm clinical results have been reported, no information on the mechanical competence of the transplanted joint surface is available. HYPOTHESIS: The mechanical competence of osteochondral autografts is maintained after transplantation. STUDY DESIGN: Controlled laboratory study. METHODS: Osteochondral defects were filled with autografts (7.45 mm in diameter) in one femoral condyle in 12 mature sheep. The ipsilateral femoral condyle served as the donor site, and the resulting defect (8.3 mm in diameter) was left empty. The repair response was examined after 3 and 6 months with mechanical and histologic assessment and histomorphometric techniques. RESULTS: Good surface congruity and plug placement was achieved. The Young modulus of the grafted cartilage significantly dropped to 57.5% of healthy tissue after 3 months (P < .05) but then recovered to 82.2% after 6 months. The aggregate and dynamic moduli behaved similarly. The graft edges showed fibrillation and, in some cases (4 of 6), hypercellularity and chondrocyte clustering. Subchondral bone sclerosis was observed in 8 of 12 cases, and the amount of mineralized bone in the graft area increased from 40% to 61%. CONCLUSIONS: The mechanical quality of transplanted cartilage varies considerably over a short period of time, potentially reflecting both degenerative and regenerative processes, while histologically signs of both cartilage and bone degeneration occur. CLINICAL RELEVANCE: Both the mechanically degenerative and restorative processes illustrate the complex progression of regeneration after osteochondral transplantation. The histologic evidence raises doubts as to the long-term durability of the osteochondral repair.

Long-term effects of hydrogel properties on human chondrocyte behavior

Hydrogels provide a 3-dimensional network for embedded cells and offer promise for cartilage tissue engineering applications. Nature-derived hydrogels, including alginate, have been shown to enhance the chondrocyte phenotype but are variable and not entirely controllable. Synthetic hydrogels, including polyethylene glycol (PEG)-based matrices, have the advantage of repeatability and modularity; mechanical stiffness, cell adhesion, and degradability can be altered independently. In this study, we compared the long-term in vitro effects of different hydrogels (alginate and Factor XIIIa-cross-linked MMP-sensitive PEG at two stiffness levels) on the behavior of expanded human chondrocytes and the development of construct properties. Monolayer-expanded human chondrocytes remained viable throughout culture, but morphology varied greatly in different hydrogels. Chondrocytes were characteristically round in alginate but mostly spread in PEG gels at both concentrations. Chondrogenic gene (COL2A1, aggrecan) expression increased in all hydrogels, but alginate constructs had much higher expression levels of these genes (up to 90-fold for COL2A1), as well as proteoglycan 4, a functional marker of the superficial zone. Also, chondrocytes expressed COL1A1 and COL10A1, indicative of de-differentiation and hypertrophy. After 12 weeks, constructs with lower polymer content were stiffer than similar constructs with higher polymer content, with the highest compressive modulus measured in 2.5% PEG gels. Different materials and polymer concentrations have markedly different potency to affect chondrocyte behavior. While synthetic hydrogels offer many advantages over natural materials such as alginate, they must be further optimized to elicit desired chondrocyte responses for use as cartilage models and for development of functional tissue-engineered articular cartilage.

Sacked! Workplace dismissals amongst youth employees

Limited academic attention has been afforded to young workers relative to their adult counterparts. This study addresses a phase of the employment relationship for young people that is very infrequently examined - during or around the time when the relationship ends. It examines the relative frequency of different forms of dismissal and the circumstances preceding the dismissals via a content analysis of 1259 cases of employee enquiries to a community advocacy organisation in Australia. Results indicate that dismissal was most commonly associated with bullying, harassment, and taking personal leave. Young men, compared to young women, were disproportionately likely to report allegations of misconduct as preceding dismissal, while females experienced higher rates of sexual harassment and discrimination. The research highlights the types and circumstances of dismissal across a range of employment contexts and reveals the complexities of youth employment relationships which may differ from those of the general workforce.

The impact of school connectedness on violent behavior, transport risk taking behavior and associated injuries in adolescence

Adolescents engage in many risk-taking behaviors that have the potential to lead to injury. The school environment has a significant role in shaping adolescent behavior, and this study aimed to provide additional information about the benefits associated with connectedness to school. Early adolescents aged 13 to 15 years (N = 509, 49% boys) were surveyed about school connectedness, engagement in transport and violence risk-taking, and injury experiences. Significant relations were found between school connectedness and reduced engagement in both transport and violence risk-taking, as well as fewer associated injuries. This study has implications for the area of risk-taking and injury prevention, as it suggests the potential for reducing adolescents' injury through school based interventions targeting school connectedness.

Thermal behavior and decomposition of kaolinite-potassium acetate intercalation composite

A series of kaolinite-potassium acetate intercalation composite was prepared. The thermal behavior and decomposition of these composites were investigated by simultaneous differential scanning calorimetry-thermogravimetric analysis (DSC-TGA), X-ray diffraction (XRD) and Fourier-transformation infrared (FT-IR). The XRD pattern at room temperature indicated that intercalation of potassium acetate into kaolinite causes an increase of the basal spacing from 0.718 to 1.428nm. The peak intensity of the expanded phase of the composite decreased with heating above 300°C, and the basal spacing reduced to 1.19nm at 350°C and 0.718nm at 400°C. These were supported by DSC-TGA and FT-IR measurements, where the endothermic reactions are observed between 300 and 600°C. These reactions can be divided into two stages: 1) Removal of the intercalated molecules between 300-400°C. 2) Dehydroxylation of kaolinite between 400-600°C. Significant changes were observed in the infrared bands assigned to outer surface hydroxyl, inner surface hydroxyl, inner hydroxyl and hydrogen bands.

Below the ‘tip of the iceberg’: extra-legal responses to workplace sexual harassment

Despite longstanding and explicit legal frameworks for preventing and responding to sexual harassment, only a small proportion of those sexually harassed use legal avenues of redress to seek justice. In contrast to legal cases which constitute the ‘tip of the iceberg’, this study examines extra-legal strategies — the less visible but more frequent, ‘everyday’, formal and informal organizational practices. We report on a national prevalence survey conducted by the Australian Human Rights Commission which examined how ‘targets’ use formal organizational grievance mechanisms, and/or other informal methods to redress, resist or avoid workplace sexual harassment. The findings revealed that the majority of targets do not formally report it because of fear of retribution or that nothing will be done, but they sometimes use apparently proactive or assertive alternative strategies, such as seeking informal assistance and ‘dealing with the problem themselves’. These responses occur in the context of extra-legal facets of organizational life which affect the extent to which sexual harassment and other unfavorable and discriminatory acts are tolerated.

Parents’ views about child sexual abuse prevention education : a systematic review

This paper presents the results of a systematic review of literature on the topic of parents’ views about child sexual abuse prevention education. It describes: i) what parents know about child sexual abuse prevention education; ii) what child sexual abuse prevention messages parents provide to their children and what topics they discuss; iii) what parents’ attitudes are towards child sexual abuse prevention education in schools; and iv) their preferences for content. Electronic database searches were conducted to identify relevant literature published in English relating to child sexual abuse prevention programs and parent’s views. A total of 429 papers were evaluated with 13 studies identified as meeting the study’s inclusion criteria. Worldwide, empirical research on parents’ views about child sexual abuse prevention programs is limited and more research is needed in Australia. Implications for future research and practice are outlined.

High-density lipoprotein deficiency and dyslipoproteinemia associated with venous thrombosis in men

Background-Although dyslipoproteinemia is associated with arterial atherothrombosis, little is known about plasma lipoproteins in venous thrombosis patients. Methods and Results-We determined plasma lipoprotein subclass concentrations using nuclear magnetic resonance spectroscopy and antigenic levels of apolipoproteins AI and B in blood samples from 49 male venous thrombosis patients and matched controls aged <55 years. Venous thrombosis patients had significantly lower levels of HDL particles, large HDL particles, HDL cholesterol, and apolipoprotein AI and significantly higher levels of LDL particles and small LDL particles. The quartile-based odds ratios for decreased HDL particle and apolipoprotein AI levels in patients compared with controls were 6.5 and 6.0 (95% CI, 2.3 to 19 and 2.1 to 17), respectively. Odds ratios for apolipoprotein B/apolipoprotein AI ratio and LDL cholesterol/HDL cholesterol ratio were 6.3 and 2.7 (95% CI, 1.9 to 21 and 1.1 to 6.5), respectively. When polymorphisms in genes for hepatic lipase, endothelial lipase, and cholesteryl ester transfer protein were analyzed, patients differed significantly from controls in the allelic frequency for the TaqI B1/B2 polymorphism in cholesteryl ester transfer protein, consistent with the observed pattern of lower HDL and higher LDL. Conclusions-Venous thrombosis in men aged <55 years old is associated with dyslipoproteinemia involving lower levels of HDL particles, elevated levels of small LDL particles, and an elevated ratio of apolipoprotein B/apolipoprotein AI. This dyslipoproteinemia seems associated with a related cholesteryl ester transfer protein genotype difference. © 2005 American Heart Association, Inc.

Offending Youth : Crime, Sex and Justice

Rates of female delinquency, especially for violent crimes, are increasing in most common law countries. At the same time the growth in cyber-bullying, especially among girls, appears to be a related global phenomenon. While the gender gap in delinquency is narrowing in Australia, United States, Canada and the United Kingdom, boys continue to dominate the youth who commit crime and have a virtual monopoly over sexually violent crimes. Indigenous youth continue to be vastly over-represented in the juvenile justice system in every Australian jurisdiction. The Indigenisation of delinquency is a persistent problem in other countries such as Canada and New Zealand. Young people who gather in public places are susceptible to being perceived as somehow threatening or riotous, attracting more than their share of public order policing. Professional football has been marred by repeated scandals involving sexual assault, violence and drunkenness. Given the cultural significance of footballers as role models to thousands, if not millions, of young men around the world, it is vitally important to address this problem. Offending Youth explores these key contemporary patterns of delinquency, the response to these by the juvenile justice agencies and moreover what can be done to address these problems. The book also analyses the major policy and legislative changes from the nineteenth to twenty first centuries, chiefly the shift the penal welfarism to diversion and restorative justice. Using original cases studied by Carrington twenty years ago, Offending Youth illustrates how penal welfarism criminalised young people from socially marginal backgrounds, especially Aboriginal children, children from single parent families, family-less children, state wards and young people living in poverty or in housing commission estates. A number of inquiries in Australia and the United Kingdom have since established that children committed to these institutions, supposedly for their own good, experienced systemic physical, sexual and psychological abuse during their institutionalisation. The book is dedicated to the survivors of these institutions who only now are receiving official recognition of the injustices they suffered. The underlying philosophy of juvenile justice has fundamentally shifted away from penal welfarism to embrace positive policy responses to juvenile crime, such as youth conferencing, cautions, warnings, restorative justice, circle sentencing and diversion examined in the concluding chapter. Offending Youth is aimed at a broad readership including policy makers, juvenile justice professionals, youth workers, families, teachers, politicians as well as students and academics in criminology, policing, gender studies, masculinity studies, Indigenous studies, justice studies, youth studies and the sociology of youth and deviance more generally.-- [from publisher website]