A review of the evolution of robotic-assisted total hip arthroplasty.

INTRODUCTION: Total hip arthroplasty (THA) is currently a very successful operation but continues to evolve as we try to perfect techniques and improve outcomes for our patients. Robotic hip surgery (RHS) began with the 'active' ROBODOC system in the 1980s. There were drawbacks associated with the original ROBODOC and most recently, the MAKO robot was introduced with early promising results. AIM: The aim of this paper is to provide an up-to-date review surrounding this area and discuss the pros and cons of this technique. METHODS: A literature review searching Medline, Embase, Ovidsp, Cochrane library, pubmed database and google scholar was performed searching keywords including: 'Robotic hip surgery', 'Robotic orthopaedic surgery', 'Computer assisted hip surgery', 'robotic arthroplasty', and 'computer assisted orthopaedic surgery'. CONCLUSION: Robotic hip surgery aims to tackle the limitations of the human factor in surgery by promising reproducible and reliable methods of component positioning in arthroplasty surgery. However, as orthopaedic surgeons, we must critically appraise all new technology and support the use providing there is sound robust evidence backing it

Charge Lattices and Consistency of 6D Supergravity

We extend the known consistency conditions on the low-energy theory of six-dimensional N = 1 supergravity. We review some facts about the theory of two-form gauge fields and conclude that the charge lattice Gamma for such a theory has to be self-dual. The Green-Schwarz anomaly cancellation conditions in the supergravity theory determine a sublattice of Gamma. The condition that this sublattice can be extended to a self-dual lattice Gamma leads to a strong constraint on theories that otherwise appear to be self-consistent.Comment: 15 pages. v2: minor changes; references, additional example added; v3: minor corrections and clarifications added, JHEP versio

Magnetic Resonance Imaging in Malawi: Contributions to Clinical Care, Medical Education and Biomedical Research

Advanced medical imaging technologies are generally unavailable in low income, tropical settings despite the reality that neurologic disorders are disproportionately common in such environments. Through a series of donations as well as extramural research funding support, an MRI facility opened in Blantyre, Malawi in July 2008. Resulting opportunities for studying common tropical disorders, such as malaria and schistosomiasis, in vivo are promising. The subsequent improvements in local patient care were expected and exceptional and include major revisions in basic care protocols that may eventually impact care protocols at facilities in the region that do not have recourse to MRI. In addition, advanced neuroimaging technology has energized the medical education system, possibly slowing the brain drain. Advanced technologies, though potentially associated with significant fiscal opportunity costs, may bring unexpected and extensive benefits to the healthcare and medical education systems involved

Patient and public involvement in primary care research - an example of ensuring its sustainability

Background The international literature on patient and public involvement (PPI) in research covers a wide range of issues, including active lay involvement throughout the research cycle; roles that patients/public can play; assessing impact of PPI and recommendations for good PPI practice. One area of investigation that is less developed is the sustainability and impact of PPI beyond involvement in time-limited research projects. Methods This paper focuses on the issues of sustainability, the importance of institutional leadership and the creation of a robust infrastructure in order to achieve long-term and wide-ranging PPI in research strategy and programmes. Results We use the case of a Primary Care Research Centre to provide a historical account of the evolution of PPI in the Centre and identified a number of key conceptual issues regarding infrastructure, resource allocation, working methods, roles and relationships. Conclusions The paper concludes about the more general applicability of the Centre’s model for the long-term sustainability of PPI in research

The prevalence of sarcopenia in fallers and those at risk of falls in a secondary care falls unit as measured by bioimpedance analysis

Objectives: Sarcopenia is characterised by loss of skeletal muscle mass and strength with adverse outcomes: physical disability, poor quality of life and death. Low muscle mass and strength are risk factors for falls, although there are few data available on the prevalence of sarcopenia in fallers. This study aimed to determine prevalence of sarcopenia in older people referred to a falls clinic. / Methods: Consecutive patients referred to a secondary care falls unit were recruited. Sarcopenia was diagnosed using the European Working Group on Sarcopenia definition (low muscle mass and function) and cut-off points. Bio-impedance measured appendicular skeletal muscle mass. Gait speed and grip strength were functional measures. / Results: Fifty-eight patients were recruited. Mean (SD) grip strength for women and men respectively were 17.9 (4.9) and 29.9(8.7) kg, mean (SD) gait speeds were 0.61(0.18) and 0.72 (0.4) m/s, mean (SD) appendicular skeletal muscle index in women and men were 6.98(1.0) and 7.85 (1.0) kg/m2 (p=0.018). Prevalence of sarcopenia was 9.8% (95% CI=1.6%-18%). / Conclusions: Sarcopenia, as measured by bio-impedance is not uncommon in older people accessing a secondary care falls clinic. Bio-impedance was simple to perform, although further validation against gold standard methods is needed. As nutritional and exercise interventions for sarcopenia are available, simple methods for diagnosing sarcopenia in fallers should be considered

Endemic, endangered and evolutionarily significant: cryptic lineages in Seychelles' frogs (Anura: Sooglossidae)

Cryptic diversity corresponding with island of origin has been previously reported in the endemic, geographically restricted sooglossid frogs of the Seychelles archipelago. The evolutionary pattern behind this has not been fully explored, and given current amphibian declines and the increased extinction risk faced by island species, we sought to identify evolutionarily significant units (ESUs) to address conservation concerns for these highly threatened anurans. We obtained genetic data for two mitochondrial (mtDNA) and four nuclear (nuDNA) genes from all known populations of sooglossid frog (on the islands of Mahé, Praslin and Silhouette) for phylogenetic analyses and to construct nuDNA haplotype networks. Bayesian and maximum likelihood analyses of mtDNA support the monophyly and molecular differentiation of populations in all species that occur on multiple islands. Haplotype networks using statistical parsimony revealed multiple high-frequency haplotypes shared between islands and taxa, in addition to numerous geographically distinct (island-specific) haplotypes for each species. We consider each island-specific population of sooglossid frog as an ESU and advise conservation managers to do likewise. Furthermore, our results identify each island lineage as a candidate species, evidence for which is supported by analyses of mtDNA based on Bayesian Poisson tree processes, and independent analyses of mtDNA and nuDNA using the multispecies coalescent. Our findings add to the growing understanding of the biogeography and hidden diversity within this globally important region

The Statistical Mechanics of Horizons and Black Hole Thermodynamics

Although we know that black holes are characterized by a temperature and an entropy, we do not yet have a satisfactory microscopic ``statistical mechanical'' explanation for black hole thermodynamics. I describe a new approach that attributes the thermodynamic properties to ``would-be gauge'' degrees of freedom that become dynamical on the horizon. For the (2+1)-dimensional black hole, this approach gives the correct entropy. (Talk given at the Pacific Conference on Gravitation and Cosmology, Seoul, February 1996.)Comment: 11 pages, LaTe

Polarization and magnetization dynamics of a field-driven multiferroic structure

We consider a multiferroic chain with a linear magnetoelectric coupling induced by the electrostatic screening at the ferroelectric/ferromagnet interface. We study theoretically the dynamic ferroelectric and magnetic response to external magnetic and electric fields by utilizing an approach based on coupled Landau- Khalatnikov and finite-temperature Landau-Lifshitz-Gilbert equations. Additionally, we compare with Monte Carlo calculations. It is demonstrated that for material parameters corresponding to BaTiO3/Fe the polarization and the magnetization are controllable by external magnetic and electric fields respectively

The holographic fluid dual to vacuum Einstein gravity

We present an algorithm for systematically reconstructing a solution of the (d+2)-dimensional vacuum Einstein equations from a (d+1)-dimensional fluid, extending the non-relativistic hydrodynamic expansion of Bredberg et al in arXiv:1101.2451 to arbitrary order. The fluid satisfies equations of motion which are the incompressible Navier-Stokes equations, corrected by specific higher derivative terms. The uniqueness and regularity of this solution is established to all orders and explicit results are given for the bulk metric and the stress tensor of the dual fluid through fifth order in the hydrodynamic expansion. We establish the validity of a relativistic hydrodynamic description for the dual fluid, which has the unusual property of having a vanishing equilibrium energy density. The gravitational results are used to identify transport coefficients of the dual fluid, which also obeys an interesting and exact constraint on its stress tensor. We propose novel Lagrangian models which realise key properties of the holographic fluid.Comment: 31 pages; v2: references added and minor improvements, published versio

Gravitational Radiation from Post-Newtonian Sources and Inspiralling Compact Binaries

The article reviews the current status of a theoretical approach to the problem of the emission of gravitational waves by isolated systems in the context of general relativity. Part A of the article deals with general post-Newtonian sources. The exterior field of the source is investigated by means of a combination of analytic post-Minkowskian and multipolar approximations. The physical observables in the far-zone of the source are described by a specific set of radiative multipole moments. By matching the exterior solution to the metric of the post-Newtonian source in the near-zone we obtain the explicit expressions of the source multipole moments. The relationships between the radiative and source moments involve many non-linear multipole interactions, among them those associated with the tails (and tails-of-tails) of gravitational waves. Part B of the article is devoted to the application to compact binary systems. We present the equations of binary motion, and the associated Lagrangian and Hamiltonian, at the third post-Newtonian (3PN) order beyond the Newtonian acceleration. The gravitational-wave energy flux, taking consistently into account the relativistic corrections in the binary moments as well as the various tail effects, is derived through 3.5PN order with respect to the quadrupole formalism. The binary's orbital phase, whose prior knowledge is crucial for searching and analyzing the signals from inspiralling compact binaries, is deduced from an energy balance argument.Comment: 109 pages, 1 figure; this version is an update of the Living Review article originally published in 2002; available on-line at http://www.livingreviews.org