150 research outputs found

    Comparison of Theoretical and Experimental Bending and Torsional Moments of Endodontic Files and Reamers

    Full text link
    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67347/2/10.1177_00220345670460051101.pd

    The Chattanooga Procedure: A New Technique Used for Anterior Multi-level Cervical Fusions

    Get PDF
    STUDY DESIGN: A preliminary assessment of anterior cervical fusion performed with interbody cage and DOC plate. OBJECTIVES: To describe and evaluate the efficacy and safety of the Chattanooga Procedure , a modified technique in achieving anterior cervical fusion. SUMMARY OF BACKGROUND DATA: Anterior cervical fusion with interbody bone graft and anterior plating is connnonly performed. Unfortunately, the plate has been reported to shield the graft from loading thus reducing fusion rates. The use of interbody fusion cages has been effective in the lumbar spine and has gained acceptance in the cervical spine. METHODS:. Twenty-five patients received The Chattanooga Procedure between 7/24/98 and 4/8/99. All patients had anterior discectomies and carpectomies, placement of a Harms cage packed with carpectomy bone, and application ofDePuy-Acromed DOC. Fusion was defined by radiographic evidence of trabecular bone bridging across the Harms cage. CT scans were performed on twelve randomly chosen patients to verify fusion. No external bracing was used except a soft collar as needed. Pre- and post-operative pain and functional capacity data were collected and statistically analyzed using paired t-tests. RESULTS: There were no cases of pseudoarthrosis, major neurological, vascular, or wound complications. Only one case of unresolved dysphasia was noted. The average operative time (11 0 minutes) was comparable to standard instrumented multi-level anterior cervical fusion surgeries. The average estimated blood loss was 113 ml (range, 50-750 ml). Both visual analog pain scale and Oswestry functional capacity data were significantly improved post-operatively (p\u3c 0.01). DISCUSSION: Advantages of the Chattanooga Procedure include immediate stability, support, elimination of donor site pain to iliac crest bone autograft, and a decrease in pseudoarthrosis by dividing the fusion surfaces by half. Concerns regarding this technique include an increased risk for dysphasia due to the DOC\u27s high profile. Pseudoarthrosis or instrumentation migration could also become problematic since the removal of the Harms cage could be difficult if necessary

    Assessing Big-Bang Nucleosynthesis

    Get PDF
    Systematic uncertainties in the light-element abundances and their evolution make a rigorous statistical assessment difficult. However, using Bayesian methods we show that the following statement is robust: the predicted and measured abundances are consistent with 95\% credibility only if the baryon-to-photon ratio is between 2×10102\times 10^{-10} and 6.5×10106.5\times 10^{-10} and the number of light neutrino species is less than 3.9. Our analysis suggests that the 4^4He abundance may have been systematically underestimated.Comment: 7 pages, LaTeX(2.09), 6 postscript figures (attached). A postscript version with figures can be found at ftp://astro.uchicago.edu/pub/astro/copi/assessing_BBN . (See the README file for details

    Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel

    Get PDF
    A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved

    Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure

    Get PDF
    Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies

    All-sky search for long-duration gravitational wave transients with initial LIGO

    Get PDF
    We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

    New insights into the genetic etiology of Alzheimer's disease and related dementias

    Get PDF
    Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

    All-sky search for long-duration gravitational wave transients with initial LIGO

    Get PDF
    We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

    Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

    Get PDF
    Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo
    corecore