662 research outputs found

    Cervical Spine Osteomyelitis after Esophageal Dilation in Patients with a History of Laryngectomy or Pharyngectomy and Pharyngeal Irradiation

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    Dysphagia is a common sequela of the treatment of head and neck cancer and is frequently managed with esophageal dilation in patients with dysphagia secondary to hypopharyngeal stenosis. Reported complications of esophageal dilation include bleeding, esophageal perforation, and mediastinitis. We examine four cases of cervical spine osteomyelitis presenting as a delayed complication of esophageal dilation for hypopharyngeal stenosis in patients with a history of laryngectomy or pharyngectomy and radiation with or without chemotherapy. The history of head and neck surgery and radiation in these patients further complicates the management of the cervical spine osteomyelitis

    Intraoperative Vancomycin Use in Spinal Surgery: Single Institution Experience and Microbial Trends.

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    Study Design. Retrospective Case Series.Objective. To demonstrate the microbial trends of spinal surgical site infections(SSI) in patients who had previously received crystallized vancomycin in the operative bed.Summary of Background Data. Prior large, case control series demonstrate the significant decrease in SSI with the administration of vancomycin in the wound bed.Methods. A single institution, electronic database search was conducted for all spinal surgery patients who had received prophylactic crystalline vancomycin powder in the wound bed. Patient\u27s with a prior history of wound infection, intrathecal pumps, or spinal stimulators were excludedResults. 981 consecutive patients (494 male, 487 female, mean age 59.4 years, range 16-95 years) were identified from January 2011 to June 2013. The average dose of vancomycin powder was 1.13 grams(range: 1-6 grams). 66 patients (6.71%) were diagnosed with a SSI of which 51 patients had positive wound cultures (5.2%). Of the 51 positive cultures the most common organism was Staphylococcus aureus. The average dose of vancomycin was 1.3 grams in the 38 cases where a gram-positive organism was cultured. A number of gram-negative infections were encountered such as Serratia marcescens, Enterobacter aerogenes, Bacteroides fragilis, Enterobacter cloacae, Citrobacter koseri and Pseudomonas aeruginosa. The average dose of vancomycin was 1.2 grams in 23 cases where a gram negative infection was cultured. 15 of the 51 (29.4%) positive-cultures were polymicrobial. 8 (53%) of these 15 polymicrobial cultures contained three or more distinct organisms.Conclusion. Prophylactic intraoperative vancomycin use in the wound bed in spinal surgery may increase the incidence of gram-negative or polymicrobial spinal infections. The use of intraoperative vancomycin may correlate with postoperative seromas, due to the high incidence of non-positive cultures. Large, randomized, prospective trials are needed to demonstrate causation and dose-response relationship

    A voting approach to identify a small number of highly predictive genes using multiple classifiers

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    <p>Abstract</p> <p>Background</p> <p>Microarray gene expression profiling has provided extensive datasets that can describe characteristics of cancer patients. An important challenge for this type of data is the discovery of gene sets which can be used as the basis of developing a clinical predictor for cancer. It is desirable that such gene sets be compact, give accurate predictions across many classifiers, be biologically relevant and have good biological process coverage.</p> <p>Results</p> <p>By using a new type of multiple classifier voting approach, we have identified gene sets that can predict breast cancer prognosis accurately, for a range of classification algorithms. Unlike a wrapper approach, our method is not specialised towards a single classification technique. Experimental analysis demonstrates higher prediction accuracies for our sets of genes compared to previous work in the area. Moreover, our sets of genes are generally more compact than those previously proposed. Taking a biological viewpoint, from the literature, most of the genes in our sets are known to be strongly related to cancer.</p> <p>Conclusion</p> <p>We show that it is possible to obtain superior classification accuracy with our approach and obtain a compact gene set that is also biologically relevant and has good coverage of different biological processes.</p

    Application of Equilibrium Models of Solution Hybridization to Microarray Design and Analysis

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    Background: The probe percent bound value, calculated using multi-state equilibrium models of solution hybridization, is shown to be useful in understanding the hybridization behavior of microarray probes having 50 nucleotides, with and without mismatches. These longer oligonucleotides are in widespread use on microarrays, but there are few controlled studies of their interactions with mismatched targets compared to 25-mer based platforms. Principal Findings: 50-mer oligonucleotides with centrally placed single, double and triple mismatches were spotted on an array. Over a range of target concentrations it was possible to discriminate binding to perfect matches and mismatches, and the type of mismatch could be predicted accurately in the concentration midrange (100 pM to 200 pM) using solution hybridization modeling methods. These results have implications for microarray design, optimization and analysis methods. Conclusions: Our results highlight the importance of incorporating biophysical factors in both the design and the analysis of microarrays. Use of the probe ‘‘percent bound’ ’ value predicted by equilibrium models of hybridization is confirmed to be important for predicting and interpreting the behavior of long oligonucleotide arrays, as has been shown for shor

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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    An embedding technique to determine ττ backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

    Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

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    Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe

    Search for dark matter in events with a leptoquark and missing transverse momentum in proton-proton collisions at 13 TeV

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    A search is presented for dark matter in proton-proton collisions at a center-of-mass energy of root s= 13 TeV using events with at least one high transverse momentum (p(T)) muon, at least one high-p(T) jet, and large missing transverse momentum. The data were collected with the CMS detector at the CERN LHC in 2016 and 2017, and correspond to an integrated luminosity of 77.4 fb(-1). In the examined scenario, a pair of scalar leptoquarks is assumed to be produced. One leptoquark decays to a muon and a jet while the other decays to dark matter and low-p(T) standard model particles. The signature for signal events would be significant missing transverse momentum from the dark matter in conjunction with a peak at the leptoquark mass in the invariant mass distribution of the highest p(T) muon and jet. The data are observed to be consistent with the background predicted by the standard model. For the first benchmark scenario considered, dark matter masses up to 500 GeV are excluded for leptoquark masses m(LQ) approximate to 1400 GeV, and up to 300 GeV for m(LQ) approximate to 1500 GeV. For the second benchmark scenario, dark matter masses up to 600 GeV are excluded for m(LQ) approximate to 1400 GeV. (C) 2019 The Author(s). Published by Elsevier B.V.Peer reviewe

    Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

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