1,572 research outputs found

    Nodal involvement evaluation in advanced cervical cancer: a single institutional experience

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    Purpose: To assess the usefulness of different imaging techniques in the detection of nodal involvement in patients with advanced cervical carcinoma. Moreover, to analyze the correlation between the presurgical (FIGO) and postsurgical (pTNM) staging classifications. Materials and Methods: All patients diagnosed with advanced cervical cancer (FIGO Stages IIB-IV) from 2005 to 2012 were selected. The medical charts of 51 patients that underwent presurgical assessment with posterior surgical staging by means of paraaortic lymphadenectomy, were reviewed. Nodal status assessment by computed tomography scan (CT scan), magnetic resonance imaging (MRI), positron emission tomography (PET), and sonography was compared, as well as the size given in imaging techniques compared to the final pathologic report information. Results: Presurgical analysis by CT scan, MRI, PET, and sonography showed pelvic nodal involvement in 51.3% of patients, and para-aortic involvement in 30.8% of cases. CT scan showed positive pelvic nodes in 35% of cases, but pathologic confirmation was observed in just 17.6% of cases. However, MRI resulted in higher rates of up to 48.8% of cases. Concerning para-aortic nodal involvement, CT scan showed positive nodes in 25% of cases, MRI in 3.2% of cases, and the pathologic report in 15.6% of cases. The authors found significant differences between staging groups among both classifications (FIGO vs. pTNM; p < 0.001). Eight cases (15.7%) were understaged by FIGO classification. Conclusions: Despite all imaging techniques available, none has demonstrated to be efficient enough to avoid the systematic study of para-aortic nodal status by means of surgical evaluatio

    Nonlinear Channel Equalization Approach for Microwave Communication Systems

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    The theoretical principles of intersymbol interference (ISI) and channel equalization in wireless communication systems are addressed. Several conventional and well-known equalization techniques are discussed and compared such as zero forcing (ZF) and maximum likelihood (ML). The main section in this chapter is devoted to an abstract concept of equalization approach, namely, dual channel equalization (DCE). The proposed approach is flexible and can be employed and integrated with other linear and nonlinear equalization approaches. Closed expressions for the achieved signal-to-noise ratio (SNR) and bit error rate (BER) in the case of ZF-DCE and ML-DCE are derived. According to the obtained outcomes, the DCE demonstrates promising improvements in the equalization performance (BER reduction) in comparison with the conventional techniques

    Use of a tyrosine kinase inhibitor as neoadjuvant therapy for non-small cell lung cancer: A case report

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    We report here a 66-year-old woman diagnosed with bronchioloalveolar carcinoma of the right lung cT4N2M0. The patient was from the Philippines, had never smoked, and tested positive for an EGFR mutation. She received gefitinib as neoadjuvant therapy for two months and displayed a partial response. The tumour was resected by performing a right pneumonectomy. The residual viable tumour accounted for less than 10%. Adjuvant chemotherapy with carboplatin-taxol was administered for four cycles. Fifteen months post-surgery, two brain metastases were found. Gefitinib was prescribed, and one month later complete radiological response was assessed. The patient remains asymptomatic and without visible disease four months later. Controlled randomised trials are needed to clarify the role of these target therapies in the neoadjuvant settin

    From circular paths to elliptic orbits: A geometric approach to Kepler's motion

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    The hodograph, i.e. the path traced by a body in velocity space, was introduced by Hamilton in 1846 as an alternative for studying certain dynamical problems. The hodograph of the Kepler problem was then investigated and shown to be a circle, it was next used to investigate some other properties of the motion. We here propose a new method for tracing the hodograph and the corresponding configuration space orbit in Kepler's problem starting from the initial conditions given and trying to use no more than the methods of synthetic geometry in a sort of Newtonian approach. All of our geometric constructions require straight edge and compass only.Comment: 9 pages, 4 figure

    Geology of the Falcón Basin (NW Venezuela)

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    This paper presents a geological map and cross-section of the Falcón Basin based both on published and unpublished work and on new data collected in the northern and southern basin margins. The geological map covers an area of 4600 km2 at 1:100,000 scale. The cross- section is oriented NNW-SSE, traversing perpendicular to the main structures. In general, the structure of the study area results from the inversion of a graben (Oligocene-early Miocene back-arc basin), that started in the middle Miocene due to the convergence between the Caribbean and South American plates. The map, the cross-section and the observations made in the field have been used to generate a tectonostratigraphic reconstruction of the Falcón Basin. The Oligocene-early Miocene sedimentary succession mapped and described is relevant to the hydrocarbon exploration in the Caribbean and in the Gulf of Venezuela, where new hydrocarbon resources have recently been discovered (i.e. Perla gas field)

    Common Hypercyclic Vectors for the Conjugate Class of a Hypercyclic Operator

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    Given a separable, infinite dimensional Hilbert space, it was recently shown by the authors that there is a path of chaotic operators, which is dense in the operator algebra with the strong operator topology, and along which every operator has the exact same dense Gδ set of hypercyclic vectors. In the present work, we show that the conjugate set of any hypercyclic operator on a separable, infinite dimensional Banach space always contains a path of operators which is dense with the strong operator topology, and yet the set of common hypercyclic vectors for the entire path is a dense Gδ set. As a corollary, the hypercyclic operators on such a Banach space form a connected subset of the operator algebra with the strong operator topology
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