Development of calcium phosphate cement for the augmentation of traumatically fractured porcine specimens using vertebroplasty

The study aim was to develop and apply an experimental technique to determine the biomechanical effect of polymethylmethacrylate (PMMA) and calcium phosphate (CaP) cement on the stiffness and strength of augmented vertebrae following traumatic fracture. Twelve burst type fractures were generated in porcine three-vertebra segments. The specimens were randomly split into two groups (n=6), imaged using microCT and tested under axial loading. The two groups of fractured specimens underwent a vertebroplasty procedure, one group was augmented with CaP cement designed and developed at Queen's University Belfast. The other group was augmented with PMMA cement (WHW Plastics, Hull, UK). The specimens were imaged and re-tested . An intact single vertebra specimen group (n=12) was also imaged and tested under axial loading. A significant decrease (p<0.01) was found between the stiffness of the fractured and intact groups, demonstrating that the fractures generated were sufficiently severe, to adversely affect mechanical behaviour. Significant increase (p<0.01) in failure load was found for the specimen group augmented with the PMMA cement compared to the pre-augmentation group, conversely, no significant increase (p<0.01) was found in the failure load of the specimens augmented with CaP cement, this is attributed to the significantly (p<0.05) lower volume of CaP cement that was successfully injected into the fracture, compared to the PMMA cement. The effect of the percentage of cement fracture fill, cement modulus on the specimen stiffness and ultimate failure load could be investigated further by using the methods developed within this study to test a more injectable CaP cement.

Experimental and Computational Approach Investigating Burst Fracture Augmentation Using PMMA and Calcium Phosphate Cements

The aim of the study was to use a computational and experimental approach to evaluate, compare and predict the ability of calcium phosphate (CaP) and poly (methyl methacrylate) (PMMA) augmentation cements to restore mechanical stability to traumatically fractured vertebrae, following a vertebroplasty procedure. Traumatic fractures (n = 17) were generated in a series of porcine vertebrae using a drop-weight method. The fractured vertebrae were imaged using μCT and tested under axial compression. Twelve of the fractured vertebrae were randomly selected to undergo a vertebroplasty procedure using either a PMMA (n = 6) or a CaP cement variation (n = 6). The specimens were imaged using μCT and re-tested. Finite element models of the fractured and augmented vertebrae were generated from the μCT data and used to compare the effect of fracture void fill with augmented specimen stiffness. Significant increases (p <0.05) in failure load were found for both of the augmented specimen groups compared to the fractured group. The experimental and computational results indicated that neither the CaP cement nor PMMA cement could completely restore the vertebral mechanical behavior to the intact level. The effectiveness of the procedure appeared to be more influenced by the volume of fracture filled rather than by the mechanical properties of the cement itself.

Does Basel Compliance Matter for Bank Performance ?

The global financial crisis underscored the importance of regulation and supervision to a well functioning banking system that efficiently channels financial resources into investment. In this paper, we contribute to the ongoing policy debate by assessing whether compliance with international regulatory standards and protocols enhances bank operating efficiency. We focus specifically on the adoption of international capital standards and the Basel Core Principles for Effective Bank Supervision (BCP). The relationship between bank efficiency and regulatory compliance is investigated using the (Simar and Wilson 2007) double bootstrapping approach on an international sample of publicly listed banks. Our results indicate that overall BCP compliance, or indeed compliance with any of its individual chapters, has no association with bank efficiency.

Does Basel Compliance Matter for Bank Performance?

The global financial crisis underscored the importance of regulation and supervision to a well-functioning banking system that efficiently channels financial resources into investment. In this paper, we contribute to the ongoing policy debate by assessing whether compliance with international regulatory standards and protocols enhances bank operating efficiency. We focus specifically on the adoption of international capital standards and the Basel Core Principles for Effective Bank Supervision (BCP). The relationship between bank efficiency and regulatory compliance is investigated using the Simar and Wilson (2007. J. Econ. 136 (1), 31) double bootstrapping approach on an international sample of publicly listed banks. Our results indicate that overall BCP compliance, or indeed compliance with any of its individual chapters,has no association with bank efficiency.

Introduction: dispersed minorities and non-territorial autonomy

The concept of non-territorial autonomy gives rise to at least two important questions: the range of functional areas over which autonomy extends, and the extent to which this autonomy is indeed non-territorial. A widely used early description significantly labelled this ‘national cultural autonomy’, implying that its focus is mainly on cultural matters, such as language, religion, education and family law. In many of the cases that are commonly cited, ‘autonomy’ may not even extend this far: its most visible expression is the existence of separate electoral registers or quotas for the various groups. Part of the dilemma lies in the difficulty of devolving substantial power on a non-territorial basis: to the extent that devolved institutions are state-like, they ideally require a defined territory. Ethnic groups, however, vary in the extent to which they are territorially concentrated, and therefore in the degree to which any autonomous arrangements for them are territorial or non-territorial. This article explores the dilemma generated by this tension between ethnic geography (pattern of ethnic settlement) and political autonomy (degree of selfrule), and introduces a set of case studies where the relationship between these two features is discussed further: the Ottoman empire and its successor states, the Habsburg monarchy, the Jewish minorities of Europe, interwar Estonia, contemporary Belgium, and two indigenous peoples, the Sa´mi in Norway and the Maori in New Zealand.

Conclusion: patterns of non-territorial autonomy

This article seeks to generalise about the significance of non-territorial autonomy as a mechanism for the management of ethnic conflict on the basis of a set of case studies covering the Ottoman empire and its successor states, the Habsburg monarchy, the Jewish minorities of Europe, interwar Estonia, contemporary Belgium, and two indigenous peoples, the Sami in Norway and Maori in New Zealand. It begins by assessing the extent to which the spatial distribution of ethnonational communities determined the range of autonomy options available—whether these might be territorial or whether only non-territorial autonomy would be realistic. The article continues with an assessment of the significance of ‘autonomy’ in circumstances where the institutions with which it is associated enjoy a non-territorial rather than a territorial writ. It concludes by suggesting that in almost all cases where autonomy is extended to a minority within a state this is exercised on a territorial basis, and that in many cases of non-territorial autonomy, or national–cultural autonomy, the powers assumed by the ‘autonomous’ institutions are substantially symbolic. It argues that notwithstanding the limited empirical evidence for the existence of non-territorial autonomy, this device should not be written off at a normative level.