2,837 research outputs found

    The accuracy of frozen section analysis in ultrasound- guided core needle biopsy of breast lesions

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    <p>Abstract</p> <p>Background</p> <p>Limited data are available to evaluate the accuracy of frozen section analysis and ultrasound- guided core needle biopsy of the breast.</p> <p>Methods</p> <p>In a retrospective analysis data of 120 consecutive handheldultrasound- guided 14- gauge automated core needle biopsies (CNB) in 109 consecutive patients with breast lesions between 2006 and 2007 were evaluated.</p> <p>Results</p> <p>In our outpatient clinic120 CNB were performed. In 59/120 (49.2%) cases we compared histological diagnosis on frozen sections with those on paraffin sections of CNB and finally with the result of open biopsy. Of the cases 42/59 (71.2%) were proved to be malignant and 17/59 (28.8%) to be benign in the definitive histology. 2/59 (3.3%) biopsies had a false negative frozen section result. No false positive results of the intraoperative frozen section analysis were obtained, resulting in a sensitivity, specificity and positive predicting value (PPV) and negative predicting value (NPV) of 95%, 100%, 100% and 90%, respectively. Histological and morphobiological parameters did not show up relevance for correct frozen section analysis. In cases of malignancy time between diagnosis and definitive treatment could not be reduced due to frozen section analysis.</p> <p>Conclusion</p> <p>The frozen section analysis of suspect breast lesions performed by CNB displays good sensitivity/specificity characteristics. Immediate investigations of CNB is an accurate diagnostic tool and an important step in reducing psychological strain by minimizing the period of uncertainty in patients with breast tumor.</p

    Comparative analysis of digital data conversion algorithms in NC systems of machine tools

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    The research is aimed at studying the selection of instruments to encode, convert and compress digital data for various purposes. Hardware and software approaches to data conversion are considered. Two approaches are distinguished and described among many hardware realizations as most suitable for control systems - matrix-based and pulse-counting methods and corresponding circuits, with their advantages and disadvantages highlighted. Software-based algorithmic solutions are recommended as providing more flexible, reliable, compact and fast-response functioning in many aspects. Computational and table-based software algorithms for NC systems of machine tools (lathes and mills) are analysed and compared using a computer program developed for that purpose. The analysis is aimed at checking whether the differences between the algorithms are significant and finding an algorithm which would provide a higher operation speed in control systems of lathes and mills. The computational algorithm is concluded to be more suitable for NC systems of those machine tools, but it is stressed that the table-based method is more appropriate for certain purposes and applications. © 2021 Author(s).Ministry of Education and Science of the Russian Federation, Minobrnauka, (075-02-2022-877)Russian Science Foundation, RSF, (21-71-00044)The present research work consists of theoretical and computational parts, which were supported by different financial sources. E.A.T. acknowledges the Russian Science Foundation (Project No. 21-71-00044) for the development of the boundary integral method. L.V.T. is grateful to the financial support from the Ministry of Science and Higher Education of the Russian Federation (Project 075-02-2022-877 for the development of the regional scientific and educational mathematical center “Ural Mathematical Center”) for the development of the selection criteria, computer simulations, and numerical examples

    Presentation of Severe Acute Respiratory Syndrome-Coronavirus 2 Infection as Cholestatic Jaundice in Two Healthy Adolescents

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    © 2020 Elsevier Inc. Liver abnormalities in severe acute respiratory syndrome-coronavirus 2 infection, including hepatitis and cholestasis, have been observed in adults and are associated with worse outcomes. We describe 2 adolescents with cholestasis and hepatitis with mild presentation of severe acute respiratory syndrome-coronavirus 2 lacking typical symptoms. Our intention is to raise index of suspicion for testing and protective equipment use

    On selection of optimal stop position and spatial orientation of mobile robot

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    The paper analyses the problem of finding optimal coordinates of a mobile robot equipped with a manipulator. An optimization criterion is proposed and validated, and a method for calculating most rational coordinates of the robot is described. © Published under licence by IOP Publishing Ltd

    The CXCR4/CXCR7/CXCL12 Axis Is Involved in a Secondary but Complex Control of Neuroblastoma Metastatic Cell Homing.

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    Neuroblastoma (NB) is one of the most deadly solid tumors of the young child, for which new efficient and targeted therapies are strongly needed. The CXCR4/CXCR7/CXCL12 chemokine axis has been involved in the progression and organ-specific dissemination of various cancers. In NB, CXCR4 expression was shown to be associated to highly aggressive undifferentiated tumors, while CXCR7 expression was detected in more differentiated and mature neuroblastic tumors. As investigated in vivo, using an orthotopic model of tumor cell implantation of chemokine receptor-overexpressing NB cells (IGR-NB8), the CXCR4/CXCR7/CXCL12 axis was shown to regulate NB primary and secondary growth, although without any apparent influence on organ selective metastasis. In the present study, we addressed the selective role of CXCR4 and CXCR7 receptors in the homing phase of metastatic dissemination using an intravenous model of tumor cell implantation. Tail vein injection into NOD-scid-gamma mice of transduced IGR-NB8 cells overexpressing CXCR4, CXCR7, or both receptors revealed that all transduced cell variants preferentially invaded the adrenal gland and typical NB metastatic target organs, such as the liver and the bone marrow. However, CXCR4 expression favored NB cell dissemination to the liver and the lungs, while CXCR7 was able to strongly promote NB cell homing to the adrenal gland and the liver. Finally, coexpression of CXCR4 and CXCR7 receptors significantly and selectively increased NB dissemination toward the bone marrow. In conclusion, CXCR4 and CXCR7 receptors may be involved in a complex and organ-dependent control of NB growth and selective homing, making these receptors and their inhibitors potential new therapeutic targets

    Nonlinear equation for curved stationary flames

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    A nonlinear equation describing curved stationary flames with arbitrary gas expansion θ=ρfuel/ρburnt\theta = \rho_{{\rm fuel}}/\rho_{{\rm burnt}}, subject to the Landau-Darrieus instability, is obtained in a closed form without an assumption of weak nonlinearity. It is proved that in the scope of the asymptotic expansion for θ1,\theta \to 1, the new equation gives the true solution to the problem of stationary flame propagation with the accuracy of the sixth order in θ1.\theta - 1. In particular, it reproduces the stationary version of the well-known Sivashinsky equation at the second order corresponding to the approximation of zero vorticity production. At higher orders, the new equation describes influence of the vorticity drift behind the flame front on the front structure. Its asymptotic expansion is carried out explicitly, and the resulting equation is solved analytically at the third order. For arbitrary values of θ,\theta, the highly nonlinear regime of fast flow burning is investigated, for which case a large flame velocity expansion of the nonlinear equation is proposed.Comment: 29 pages 4 figures LaTe

    High quality anti-relaxation coating material for alkali atom vapor cells

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    We present an experimental investigation of alkali atom vapor cells coated with a high quality anti-relaxation coating material based on alkenes. The prepared cells with single compound alkene based coating showed the longest spin relaxation times which have been measured up to now with room temperature vapor cells. Suggestions are made that chemical binding of a cesium atom and an alkene molecule by attack to the C=C bond plays a crucial role in such improvement of anti-relaxation coating quality
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