The effect of modular tapered fluted stems on proximal stress shielding in the human femur.

Modular hip implants are currently being used in total hip arthroplasty revision procedures because it is common to have little or no bone left in the proximal region of the femur and it is difficult to accurately size implants based off of radiographs or other medical imaging techniques. The effect of modular systems using tapered fluted stems on proximal stress shielding in the human femur is the focus of this study. Seven modular implants were press-fit into seven femurs, where there was little or no contact between the modular body and the test femur. Finally, hydroxyapatite bone cement was added to create an interface between the modular body and femur. Stress shielding is perhaps one of the most critical complications that occur after total hip arthroplasty (THA). Insertion of the prosthesis permanently alters the stress distribution in the human femur. Stress shielding occurs in those areas in which a bone experiences a reduction of stress. Essentially, the prosthesis shields the stress from the bone by transmitting the force through the implant rather than the bone, which can lead to a decrease in bone mineral density due to the reduction of stress or failure of the implant itself. Seven test femurs were instrumented with strain gages to measure the strain at three different levels. Two loading conditions were applied to represent the forces exerted on the femur when a human is in a natural standing position. The loading conditions were applied to the intact femur: when the prosthesis was inserted into the femur with a press-fit; and when hydroxyapatite bone cement was injected around the implant in the proximal region. All femurs exhibited stress shielding effects after surgically inserting the modular implants. The experimental data confirmed that the greatest amount of stress shielding occurred primarily in the proximal and mid-stem regions. The strains at the junction between the modular body and stem were relatively low. The experimental data also confirmed that with the addition of BoneSource® Hydroxyapatite cement the strain in the proximal and mid-stem regions significantly increased, but stress shielding still occurred. The strains at the junction between the body and stem also decreased

Web Accessibility in Corporate Australia: Perceptions versus Reality

In this paper we describe the results of website audits and survey responses for organizations involved in the Australia Web Awards for 2011. 160 organizations entered their sites or sites they had developed as part of the awards, and in doing so were required to select the level of WCAG compliance for their site. Audits conducted on these sites after the awards completion showed that very few of the entrants actually met their selected level of accessibility compliance, regardless of the organization type. Survey responses from participating entrants in the AWA indicated that they were aware of the WCAG guidelines and various levels of compliance, and had experience in accessible design. Entrants also indicated knowledge of accessibility tools and methodologies, yet failed to produce sites with even rudimentary levels of accessibility. The paper concludes that whilst the Australian government is moving towards a framework of mandatory accessibility, the developers and designers involved in this study still see accessibility as largely optional

Poster 153: Walking Assessment in People With Lumbar Spinal Stenosis: Capacity, Performance, and Self‐report Measures

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146939/1/pmr2s71a.pd

Reference-Free Validation of Short Read Data

High-throughput DNA sequencing techniques offer the ability to rapidly and cheaply sequence material such as whole genomes. However, the short-read data produced by these techniques can be biased or compromised at several stages in the sequencing process; the sources and properties of some of these biases are not always known. Accurate assessment of bias is required for experimental quality control, genome assembly, and interpretation of coverage results. An additional challenge is that, for new genomes or material from an unidentified source, there may be no reference available against which the reads can be checked.-mers. We apply our methodology to wide range of short read data and show that, surprisingly, strong biases appear to be present. These include gross overrepresentation of some poly-base sequences, per-position biases towards some bases, and apparent preferences for some starting positions over others.The existence of biases in short read data is known, but they appear to be greater and more diverse than identified in previous literature. Statistical analysis of a set of short reads can help identify issues prior to assembly or resequencing, and should help guide chemical or statistical methods for bias rectification

The surface activity and rheological changes induced in lung surfactant resulting from ozone exposure

Lung surfactant is a complex mixture of phospholipids and membrane proteins that is located on the surface of alveoli within our lungs. Lung surfactant reduces the work associated with respiration and prevents the collapse of the alveoli sacs during , breathing. The function of lung surfactant depends on lipid and membrane protein biophysical interactions which may be affected by the quality of air an individual inhales. Presently there exists extensive data concerning the chemical changes ozone, a major oxidant in photochemical smog, induces within exposed lung surfactant components. There is however little research focused on the biophysical impacts of lung surfactant oxidation. This research examines the surface activity, film morphology and rheological changes induced in model lung surfactant films by ozone exposure. These experiments will use monolayers as a model system to investigate film oxidation changes. The results of this research show that both unsaturated lipids and membrane proteins are ozone sensitive. The ozonolysis of films comprised of pure lipids and lipid-protein mixtures exhibit changes to surface activity, film organization and rheology. However, when membrane proteins are present the changes to film rheology after ozone exposure are not measurable. This thesis examines the molecular interactions that lead to these film property changes and relates them to lung surfactant physiological behavior

Three-dimensional BF Theories and the Alexander-Conway Invariant of Knots

We study 3-dimensional BF theories and define observables related to knots and links. The quantum expectation values of these observables give the coefficients of the Alexander-Conway polynomial.Comment: 32 pages (figures available upon request); LaTe

Privately Matching kk-mers

We construct the first noninteractive protocols for several tasks related to private set intersection. We provide efficient protocols for three related problems, each motivated by a particular kind of genomic testing. Set intersection with labelling hides the intersecting set itself and returns only the labels of the common elements, thus allowing a genomics company to return diagnoses without exposing the IP of its database. Fuzzy matching with labelling extends this to allow matching at a particular Hamming distance, which solves the same problem but incorporates the possibility of genetic variation. Closest matching returns the item in the server\u27s database closest to the client\u27s query - this can be used for taxonomic classification. Our protocols are optimised for the matching of $k$-mers (sets of $k$-length strings) rather than individual nucleotides, which is particularly useful for representing the short reads produced by next generation sequencing technologies

Short read sequence typing (SRST): multi-locus sequence types from short reads.

BACKGROUND: Multi-locus sequence typing (MLST) has become the gold standard for population analyses of bacterial pathogens. This method focuses on the sequences of a small number of loci (usually seven) to divide the population and is simple, robust and facilitates comparison of results between laboratories and over time. Over the last decade, researchers and population health specialists have invested substantial effort in building up public MLST databases for nearly 100 different bacterial species, and these databases contain a wealth of important information linked to MLST sequence types such as time and place of isolation, host or niche, serotype and even clinical or drug resistance profiles. Recent advances in sequencing technology mean it is increasingly feasible to perform bacterial population analysis at the whole genome level. This offers massive gains in resolving power and genetic profiling compared to MLST, and will eventually replace MLST for bacterial typing and population analysis. However given the wealth of data currently available in MLST databases, it is crucial to maintain backwards compatibility with MLST schemes so that new genome analyses can be understood in their proper historical context. RESULTS: We present a software tool, SRST, for quick and accurate retrieval of sequence types from short read sets, using inputs easily downloaded from public databases. SRST uses read mapping and an allele assignment score incorporating sequence coverage and variability, to determine the most likely allele at each MLST locus. Analysis of over 3,500 loci in more than 500 publicly accessible Illumina read sets showed SRST to be highly accurate at allele assignment. SRST output is compatible with common analysis tools such as eBURST, Clonal Frame or PhyloViz, allowing easy comparison between novel genome data and MLST data. Alignment, fastq and pileup files can also be generated for novel alleles. CONCLUSIONS: SRST is a novel software tool for accurate assignment of sequence types using short read data. Several uses for the tool are demonstrated, including quality control for high-throughput sequencing projects, plasmid MLST and analysis of genomic data during outbreak investigation. SRST is open-source, requires Python, BWA and SamTools, and is available from http://srst.sourceforge.net

Non-perturbative flow equations from continuous unitary transformations

We use a novel parameterization of the flowing Hamiltonian to show that the flow equations based on continuous unitary transformations, as proposed by Wegner, can be implemented through a nonlinear partial differential equation involving one flow parameter and two system specific auxiliary variables. The implementation is non-perturbative as the partial differential equation involves a systematic expansion in fluctuations, controlled by the size of the system, rather than the coupling constant. The method is applied to the Lipkin model to construct a mapping which maps the non-interacting spectrum onto the interacting spectrum to a very high accuracy. This function is universal in the sense that the full spectrum for any (large) number of particles can be obtained from it. In a similar way expectation values for a large class of operators can be obtained, which also makes it possible to probe the stucture of the eigenstates.Comment: 24 pages, 13 figure