Nano- and macro-scale characterisation of the mechanical properties of bovine bone

In the present study, nano- and macro-scale characterisations on the mechanical properties of bovine cortical bones have been performed by using nanoindentation and conventional compressive tests. Nanoindentation results showed that the elastic modulus for the osteons and the interstitial lamellae in the longitude direction were 24.7 ± 2.5 GPa and 30.1 ± 2.4 GPa. As it’s difficult to distinguish osteons from interstitial lamellae in the transverse direction, the average elastic modulus for cortical bovine bone in the transverse direction was 19.8 ± 1.6 GPa. Significant differences were found in the modulus values between different microstructures of bone tissue and in different testing direction. It was found that the elastic modulus of bone bovine material in nano-level was higher than that in macro-level. The elastic modulus and
ultimate stress of large bone samples were 12.5 ± 1.9 GPa and 195 ± 19 MPa respectively from the compression test.

Improving the quality of life for patients' with co-morbidities requiring acute care

Reduced mortality rates in the Western world have created an increase in people with co-morbidities who have the potential to require acute care hospital services. These patients' chronic conditions often require complex needs that may not always be met by an acute care focus. This has created a precedent for nurses concerned with the holistic care and quality of life for these patients. This paper aims to describe the experiences of patients with co-morbidities who were admitted to hospital with an acute illness. This exploratory descriptive design selected patients in acute care who had more than one co-morbidity for approximately five years. Data was obtained from a purposive sample of twelve patients within two weeks of being discharged home using a semi-structured interview approach. Data analysis was conducted utilising Nvivo software to process the Colaizzi [1978] method. The theme clusters revealed a lack of continuity and co-ordinated care of the patients' co-morbidities during the acute admission and in discharge planning. It was seen that combinations of chronic conditions and treatments affected these patients' experience of acute care and thereafter, where conceptualisations of co-morbidity failed to accurately capture the underlying health care needs of these patients. These findings have implications for a comprehensive and considered approach to these patients' health care needs and quality of life whilst developing an improved understanding of co-morbidity for nursing. Recommendations for further research conclude this paper.

Small diameter Polyurethane vascular graft reinforced by elastic weft-knitted tubular fabric of polyester / spandex

Small diameter vascular grafts were fabricated from pure Polyurethane (PU) as well as PU reinforced with a tubular weft-knitted fabric. The tensile properties of the reinforced composite vascular grafts were compared with that of the tubular fabric itself and the pure PU vascular grafts. The elasticity and strength of the reinforced vascular grafts were improved compared with the tubular fabric. Strength of the reinforced vascular grafts was 5–10 times of the strength of the pure PU vascular grafts. Expanding the tubular fabric to increase the inner diameter of the reinforced vascular graft reduced the graft’s strength and initial modulus, but the difference was reduced as the PU content was increased. For grafts of the same inner diameter, increasing the PU content increased the thickness and strength of the graft wall, which led to a general increase in the strength and initial modulus of the composite vascular grafts.

Duality theory and forms of organizing

This paper presents results from a survey of organizing forms in Australia's largest public companies between 2000 and 2004. The study sought to identify trends in forms of organizing and the extent to which the uptake of new forms led to a decrease in traditional forms of organizing. The analysis revealed changes across the organizational dimensions of structures, processes and boundaries. While Australian firms were clearly interested in exploring new forms of organizing, uptake was not universal, nor at the expense of traditional forms of organizing. An admixture of traditional and new, or dual, forms of organizing emerged as the preferred response to environmental turbulence. This paper employs and extends duality theory to explain the changes that occurred in Australian public companies over the four year period. Duality theory is operationalized in terms of five duality characteristics, which are employed to assess the composition and balance of traditional and new fOlms of organizing. The paper proposes that a dualities aware perspective offers a potential way forward in managing the balance between ostensibly contradictory forces of continuity and change.

Barriers to care for depressed older people : perceptions of aged care among medical professionals

The current study evaluated barriers to detection of depression among older people. Focus groups were conducted with 21 professional carers, 4 nurses, 10 general practitioners, and 7 aged care managers. The results demonstrated that care for older people is primarily focused on physical care. Further, staff resources, a lack of continuity of care, multiple co-morbidities, reluctance by older people to discuss depression, negative attitudes among carers, as well as a lack of skills all contributed to a failure to detect and treat depression. The implications of these findings for training programs for professional carers are discussed.

Metaphoric use of the mountain symbol in painting

This paper consists of two parts. The focus of Part I is the symbol of the mountain and its metaphoric use in art history and in the mythology of many cultures. Part II links an examination of twentieth century contemporary artists and relevant issues, the mythology and historical references covered in Part I and the paintings that make up the body of the thesis. The study is concerned with the role of the symbol and the form of its interpretation in the expression of ideas and images that are relevant to it. These themes have been developed in order to place the paintings in a context of continuity and establish iconographic links with the past. One particular site has been chosen through which to examine the symbolic associations between the mountain and the metaphoric quest. The metaphor of pilgrimage to the site and of searching for a lost unity is implicit in this process. The realisation reached at the summit confirms the significance of this journey. Each painting is discussed and linked with the themes that are relevant to it, linking the research recorded in Part I with the execution of the paintings, aiming at a synthesis of theory and practice.

Preparation of bioactive porous titanium-molybdenum alloy through powder metallurgy

Porous Ti-Mo alloy samples with different porosities from 52% to 72% were successfully fabricated by the space-holder sintering method. The pore size of the porous Ti-Mo alloy samples were ranged from 200 to 500 μm. The plateau stress and elastic modulus of the porous Ti-Mo alloy samples increases with the decreasing of the porosity. Moreover, an apatite coating on the Ti-Mo alloy after an alkali and heat treatment was obtained through soaking into a simulated body fluid (SBF). The porous Ti-Mo alloy provides promising potential for new implant materials with new bone tissue ingrowth ability, bioactivity and mechanical properties mimicking those of natural bone.

Realism and idealism in the philosophy of Charles S. Peirce

The thesis argues that there is a conjoining of realism and idealism in the mature thought of American philosopher Charles S. Peirce. Concludes that realism and idealism function together as a unit as they are both founded on an evolutionary conception of continuity and potentiality.

Biomimetic modification of porous TiNbZr alloy scaffold for bone tissue engineering

Porous titanium (Ti) and Ti alloys are important scaffold materials for bone tissue engineering. In the present study, a new type of porous Ti alloy scaffold with biocompatible alloying elements, that is, niobium (Nb) and zirconium (Zr), was prepared by a space-holder sintering method. This porous TiNbZr scaffold with a porosity of 69% exhibits a mechanical strength of 67MPa and an elastic modulus of 3.9GPa, resembling the mechanical properties of cortical bone. To improve the osteoconductivity, a calcium phosphate (Ca/P) coating was applied to the surface of the scaffold using a biomimetic method. The biocompatibility of the porous TiNbZr alloy scaffold before and after the biomimetic modification was assessed using the SaOS2 osteoblast–like cells. Cell culture results indicated that the porous TiNbZr scaffold is more favorable for cell adhesion and proliferation than its solid counterpart. By applying a Ca/P coating, the cell proliferation rate on the Ca/P-coated scaffold was significantly improved. The results suggest that high-strength porous TiNbZr scaffolds with an appropriate osteoconductive coating could be potentially used for bone tissue engineering application.

Challenges of inter-generational succession in the Chinese Australian family business

Chinese immigrants have long been a feature of Australia's population mix and play a critical role in the country's economic activities, with particular contribution by Chinese family-owned businesses. Although these family-owned businesses can generate and significantly improve the financial wealth which stems from the family's original fortune, most Chinese family businesses are relatively short-lived, rarely extending beyond one generation. The high mortality rate in family businesses points primarily to the challenges of management succession. There is recognition that inter-generational succession is essential for both the profitability of Chinese family businesses and the welfare of the family as a whole. However, the intentions of inter-generational pursuit of continuity can be subject to the different goals and interests of key participants, as well as the surrounding context in which the business develops. This paper presents issues pertaining to the inter-generational diversity that might challenge the business continuity of Chinese family businesses, through the identification of how individuals perceive, relate to and initiate the succession process.

Structure and properties of biomedical films prepared from aqueous and acidic silk fibroin solutions

Silk fibroin films are promising materials for a range of biomedical applications. To understand the effects of casting solvents on film properties, we used water (W), formic acid (FA), and trifluoroacetic acid (TFA) as solvents. We characterized molecular weight, secondary structure, mechanical properties, and degradation behavior of cast films. Significant degradation of fibroin was observed for TFA-based film compared to W and TA-based films when analyzed by SDS-PAGE. Fibroin degradation resulted in a significant reduction in tensile strength and modulus of TFA-based films. Compared to water, TFA-based films demonstrated lower water solubility (19.6% vs. 62.5% in 12 h) despite having only a marginal increase in their ß-sheet content (26.9% vs. 23.7%). On the other hand, FA-based films with 34.3% ß-sheet were virtually water insoluble. Following solubility treatment, ß-sheet content in FA-based films increased to 50.9%. On exposure to protease XIV, water-annealed FA-based films lost 74% mass in 22 days compared to only 30% mass loss by ethanol annealed FA films. This study demonstrated that a small variation in the ß-sheet percentage and random coil conformations resulted in a significant change in the rates of enzymatic degradation without alteration to their tensile properties. The film surface roughness changed with the extent of enzymatic hydrolysis.

Relative deprivation between neighbouring wards is predictive of coronary heart disease mortality after adjustment for absolute deprivation of wards

Background The aims of this study were to assess whether deprivation inequality at small area level in England is associated with coronary heart disease (CHD) mortality rates and to assess whether this provides evidence of an association between area-level and individual-level risk.

Methods Mortality rates for all wards in England were calculated using all CHD deaths between 2001 and 2006. Ward-level deprivation was measured using the Carstairs Index. Deprivation inequality within local authorities (LAs) was measured by the IQR of deprivation for wards within the LA. Relative deprivation for wards was measured as the modulus of the difference between deprivation for the ward and average deprivation for all neighbouring wards.

Results Deprivation inequality within LAs was positively associated with CHD mortality rates per 100 000 (eg, all men β; 95% CI=2.7; 1.1 to 4.3) after adjustment for absolute deprivation (p<0.001 for all models). Relative deprivation for wards was positively associated with CHD mortality rates per 100 000 (eg, all men 1.4; 0.7 to 2.1) after adjustment for absolute deprivation (p<0.001 for all models). Subgroup analyses showed that relative deprivation was independently associated with CHD mortality rates in both affluent and deprived wards.

Conclusions Rich wards surrounded by poor areas have higher CHD mortality rates than rich wards surrounded by rich areas, and poor wards surrounded by rich areas have worse CHD mortality rates than poor wards surrounded by poor areas. Local deprivation inequality has a similar adverse impact on both rich and poor areas, supporting the hypothesis that income inequality of an area has an impact on individual-level health outcomes.

Understanding of hydrogel network formation and its application in the architecture of significantly enhanced hydrogel

An understanding of the physical hydrogel network formation has been obtained by dynamic rheological experiments. The evidence shows that the network formation turns out to be a nucleation-controlled process. It was found that there exists a critical temperature Tc; fiber branching is greatly enhanced when the network formation is performed in the regime of T<Tc (T, the final setting temperature). This finding enables the authors to build significantly enhanced gel networks. So far G′ (elastic modulus) of the hydrogel network has been enhanced by 187% while the formation period can be greatly shortened to only 1/20 of the previous process.

The configuration evolution and macroscopic elasticity of fluid-filled closed cell composites : micromechanics and multiscale homogenization modelling

For fluid-filled closed cell composites widely distributed in nature, the configuration evolution and effective elastic properties are investigated using a micromechanical model and a multiscale homogenization theory, in which the effect of initial fluid pressure is considered. Based on the configuration evolution of the composite, we present a novel micromechanics model to examine the interactions between the initial fluid pressure and the macroscopic elasticity of the material. In this model, the initial fluid pressure of the closed cells and the corresponding configuration can be produced by applying an eigenstrain at the introduced fictitious stress-free configuration, and the pressure-induced initial microscopic strain is derived. Through a configuration analysis, we find the initial fluid pressure has a prominent effect on the effective elastic properties of freestanding materials containing pressurized fluid pores, and a new explicit expression of effective moduli is then given in terms of the initial fluid pressure. Meanwhile, the classical multiscale homogenization theory for calculating the effective moduli of a periodical heterogeneous material is generalized to include the pressurized fluid "inclusion" effect. Considering the coupling between matrix deformation and fluid pressure in closed cells, the multiscale homogenization method is utilized to numerically determine the macroscopic elastic properties of such composites at the unit cell level with specific boundary conditions. The present micromechanical model and multiscale homogenization method are illustrated by several numerical examples for validation purposes, and good agreements are achieved. The results show that the initial pressure of the fluid phase can strengthen overall effective bulk modulus but has no contribution to the shear modulus of fluid-filled closed cell composites.

High-pressure study of low-compressibility Ta2N

Room temperature synchrotron x-ray diffraction experiments were performed on nanocrystal Ta₂N in a diamond anvil cell to a pressure of 55.48 GPa. This nitride is a well-known kind of high-hardness material, and it is found to be highly incompressible. The structure is stable with no phase transitions observed in this pressure range. The zero-pressure bulk modulus and its pressure derivative at ambient pressure are B₀ = 360 ± 3 GPa, B₀' = 4, and in room conditions, the a and c parameters are 3.054 Å, 4.996 Å, respectively. The bulk modulus of Ta₂N is greater than those of TaC, ε-TaN, Cr₂N and MoN. The differences in bulk moduli might be due to the differences in structure and the cohesive energy among these phases.