462 research outputs found

    A Different Impression Technique for a Single Tooth Crown Over the ITI Implant

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    The single tooth implant has common use in the field of implant dentistry and many studies report high success rates. Improvements in implant design, range of prosthetic components and restorative materials have made it possible to achieve optimal cosmetic results, although tissue contouring problems may sometimes limit optimum aesthetics, especially in the anterior maxilla. This case report describes a different impression technique, by using zinc-oxide eugenol impression paste, to take a precise impression of the periimplant tissues around the subgingival part of the ITI implant, to achieve an optimal cosmetic effect

    Examination of Existent Propagation Models Over Large Inhomogeneous Terrain Profiles Using Fast Integral Equation Solution

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    Cataloged from PDF version of article.The accuracyof most widelyused empirical models are investigated using the spectrallyaccelerated forward-backward (FBSA) method as a benchmark solution. First, FBSA results are obtained for propagation over large scale terrain profiles and compared with measurements to assess the accuracyof FBSA. Then, accuracyof some International Telecommunication Union (ITU) and Federal Communications Commission (FCC) propagation models are investigated. It has been observed that, for rural areas, the prediction of the most recent ITU recommended propagation model (Rec. 1546) deviates much more than older models do

    Characteristic Basis Function Method for Solving Electromagnetic Scattering Problems over Rough Terrain Profiles

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    Cataloged from PDF version of article.A computationally efficient algorithm, which combines the characteristic basis function method (CBFM), the physical optics (PO) approach (when applicable) with the forward backward method (FBM), is applied for the investigation of electromagnetic scattering from—and propagation over—large-scale rough terrain problems. The algorithm utilizes high-level basis functions defined on macro-domains (blocks), called the characteristic basis functions (CBFs) that are constructed by aggregating low-level basis functions (i.e., conventional sub-domain basis functions). The FBM as well as the PO approach (when applicable) are used to construct the aforementioned CBFs. The conventional CBFM is slightly modified to handle large-terrain problems, and is further embellished by accelerating it, as well as reducing its storage requirements, via the use of an extrapolation procedure. Numerical results for the total fields, as well as for the path loss are presented and compared with either measured or previously published reference solutions to assess the efficiency and accuracy of the algorithm

    A Different Impression Technique for a Single Tooth Crown Over the ITI Implant

    Get PDF
    The single tooth implant has common use in the field of implant dentistry and many studies report high success rates. Improvements in implant design, range of prosthetic components and restorative materials have made it possible to achieve optimal cosmetic results, although tissue contouring problems may sometimes limit optimum aesthetics, especially in the anterior maxilla. This case report describes a different impression technique, by using zinc-oxide eugenol impression paste, to take a precise impression of the periimplant tissues around the subgingival part of the ITI implant, to achieve an optimal cosmetic effect

    Fast integral equation techniques for propagation problems

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    In this paper, the Method of Moments (MoM) solution is achieved for scattering problems by using the stationary Spectrally Accelerated Forward-Backward method (FBSA) and the non-stationary Spectrally Accelerated BiConjugate Gradient Stabilized (SA-BiCGSTAB) method, with a storage requirement and a computational cost of O(N) per iteration where N is the number of surface unknowns in the discretized integral equation. The SA-BiCGSTAB method is applied over rough terrain profiles as well as re-entrant surfaces which can not be handled by any conventional stationary iterative technique

    Epidemics in Adaptive Social Networks with Temporary Link Deactivation

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    Disease spread in a society depends on the topology of the network of social contacts. Moreover, individuals may respond to the epidemic by adapting their contacts to reduce the risk of infection, thus changing the network structure and affecting future disease spread. We propose an adaptation mechanism where healthy individuals may choose to temporarily deactivate their contacts with sick individuals, allowing reactivation once both individuals are healthy. We develop a mean-field description of this system and find two distinct regimes: slow network dynamics, where the adaptation mechanism simply reduces the effective number of contacts per individual, and fast network dynamics, where more efficient adaptation reduces the spread of disease by targeting dangerous connections. Analysis of the bifurcation structure is supported by numerical simulations of disease spread on an adaptive network. The system displays a single parameter-dependent stable steady state and non-monotonic dependence of connectivity on link deactivation rate

    Brain metastases from hepatocellular carcinoma: clinical features and prognostic factors

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    <p>Abstract</p> <p>Background</p> <p>Brain metastases (BM) from hepatocellular carcinoma (HCC) are extremely rare and are associated with a poor prognosis. The aim of this study was to define clinical outcome and prognostic determinants in patients with BM from HCC.</p> <p>Methods</p> <p>Between January 1994 and December 2009, all patients with HCC and BM treated in Sun Yat-sen University Cancer Center were retrospectively reviewed. Univariate and multivariate survival analyses were performed to identify possible prognostic factors.</p> <p>Results</p> <p>Forty-one patients were diagnosed with BM from HCC, an incidence of 0.47%. The median age at diagnosis of BM was 48.5 years. Thirty-three patients (80.5%) developed extracranial metastases at diagnosis of BM, and 30 patients (73.2%) had hepatitis B. Intracranial hemorrhage occurred in 19 patients (46.3%). BM were treated primarily either with whole brain radiation therapy (WBRT; 5 patients), stereotactic radiosurgery (SRS; 7 patients), or surgical resection (6 patients). The cause of death was systemic disease in 17 patients and neurological disease in 23. Patients in a high RPA (recursive partitioning analysis) class, treated with conservatively and without lung metastases, tended to die from neurological disease. Median survival after the diagnosis of BM was 3 months (95% confidence interval: 2.2-3.8 months). In multivariate analysis, the presence of extracranial metastases, a low RPA class and aggressive treatment, were positively associated with improved survival.</p> <p>Conclusions</p> <p>BM from HCC is rare and associated with an extremely poor prognosis. However, patients with a low RPA class may benefit from aggressive treatment. The clinical implication of extracranial metastases in HCC patients with BM needs further assessment.</p
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