The Experts below are selected from a list of 36 Experts worldwide ranked by ideXlab platform

Rafael S Andrade - One of the best experts on this subject based on the ideXlab platform.

  • true negative predictive value of endobronchial ultrasound in lung cancer are we being Conservative enough
    The Annals of Thoracic Surgery, 2013
    Co-Authors: Bryan A. Whitson, Shawn S Groth, Eleazar P Briones, Michael A Maddaus, Jonathan Dcunha, David D Odell, Rafael S Andrade
    Abstract:

    Background Mediastinal staging in patients with non-small cell lung cancer (NSCLC) with endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA) requires a high negative predictive value (NPV) (ie, low false negative rate). We provide a Conservative Calculation of NPV that calls for caution in the interpretation of EBUS results. Methods We retrospectively analyzed our prospectively gathered database (January 2007 to November 2011) to include NSCLC patients who underwent EBUS-FNA for mediastinal staging. We excluded patients with metastatic NSCLC and other malignancies. We assessed FNAs with rapid on-site evaluation (ROSE). The Calculation of NPV is NPV=true negatives/true negatives + false negatives. However, this definition ignores nondiagnostic samples. Nondiagnostic samples should be added to the NPV denominator because decisions based on nondiagnostic samples could be flawed. We Conservatively calculated NPV for EBUS-FNA as NPV=true negatives/true negatives + false negatives + nondiagnostic. We defined false negatives as negative FNAs but NSCLC-positive surgical biopsy of the same site. Nondiagnostic FNAs were nonrepresentative of lymphoid tissue. We compared diagnostic performance with the inclusion and exclusion of nondiagnostic procedures. Results We studied 120 patients with NSCLC who underwent EBUS-FNA; 5 patients had false negative findings and 10 additional patients had nondiagnostic results. The NPV with and without inclusion of nondiagnostic samples was 65.9% and 85.3%, respectively. Conclusions The inclusion of nondiagnostic specimens into the Conservative, worst-case-scenario Calculation of NPV for EBUS-FNA in NSCLC lowers the NPV from 85.3% to 65.9%. The true NPV is likely higher than 65.9% as few nondiagnostic specimens are false negatives. Caution is imperative for the safe application of EBUS-FNA in NSCLC staging.

Ramos Gutiérrez, Óscar Ramón - One of the best experts on this subject based on the ideXlab platform.

  • Methodology for the Structural integrity assessment of the "Constitución de 1812" Bridge, over the Bay of Cádiz (Cádiz, Spain)
    Elsevier B.V., 2019
    Co-Authors: Díaz García, Miguel Angel, Cicero González Sergio, Ramos Gutiérrez, Óscar Ramón
    Abstract:

    In keeping with the requirements of the latest standards for calculating structures and bridges in Spain, EHE 2008 and EAE 2011, the inspection and maintenance plan developed for the "Constitución de 1812? bridge, over the Cádiz bay, includes a section dedicated to the inspection of cracks that can appear in the steel deck. The estimation of the critical sizes of such cracks was made by completing a structural integrity assessment of the bridge deck based on the BS7910 standard, obtaining a critical size of only 6 mm in certain structural details. These crack sizes cannot be detected by visual inspection, which is in practice the inspection method used in bridges. Thus, an alternative methodology for the structural integrity assessment of bridges is proposed, with the aim of applying it to the ?Constitución de 1812? bridge. The approach is based on the use of more refined (less Conservative) Calculation options according to the BS7910 standard, and on the consideration of structural redundancy criteria.The authors of this work would like to express their gratitude to the University of Cantabria for the financial support of the project “Aplicación de Técnicas de Integridad Estructural y Fiabilidad de Materiales en la Determinacion del Ciclo de Vida de Puentes Metalicos y Mixtos” (03.DI09.649), a programme of industrial doctorates, on the results of which this paper is based

Oscar Ramon Ramos Gutierrez - One of the best experts on this subject based on the ideXlab platform.

  • methodology for the structural integrity assessment of the constitucion de 1812 bridge over the bay of cadiz cadiz spain
    Procedia structural integrity, 2019
    Co-Authors: Manuel Angel Diaz Garcia, S Cicero, Oscar Ramon Ramos Gutierrez
    Abstract:

    Abstract In keeping with the requirements of the latest standards for calculating structures and bridges in Spain, EHE 2008 and EAE 2011, the inspection and maintenance plan developed for the "Constitucion de 1812” bridge, over the Cadiz bay, includes a section dedicated to the inspection of cracks that can appear in the steel deck. The estimation of the critical sizes of such cracks was made by completing a structural integrity assessment of the bridge deck based on the BS7910 standard, obtaining a critical size of only 6 mm in certain structural details. These crack sizes cannot be detected by visual inspection, which is in practice the inspection method used in bridges. Thus, an alternative methodology for the structural integrity assessment of bridges is proposed, with the aim of applying it to the “Constitucion de 1812” bridge. The approach is based on the use of more refined (less Conservative) Calculation options according to the BS7910 standard, and on the consideration of structural redundancy criteria.

Bryan A. Whitson - One of the best experts on this subject based on the ideXlab platform.

  • true negative predictive value of endobronchial ultrasound in lung cancer are we being Conservative enough
    The Annals of Thoracic Surgery, 2013
    Co-Authors: Bryan A. Whitson, Shawn S Groth, Eleazar P Briones, Michael A Maddaus, Jonathan Dcunha, David D Odell, Rafael S Andrade
    Abstract:

    Background Mediastinal staging in patients with non-small cell lung cancer (NSCLC) with endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA) requires a high negative predictive value (NPV) (ie, low false negative rate). We provide a Conservative Calculation of NPV that calls for caution in the interpretation of EBUS results. Methods We retrospectively analyzed our prospectively gathered database (January 2007 to November 2011) to include NSCLC patients who underwent EBUS-FNA for mediastinal staging. We excluded patients with metastatic NSCLC and other malignancies. We assessed FNAs with rapid on-site evaluation (ROSE). The Calculation of NPV is NPV=true negatives/true negatives + false negatives. However, this definition ignores nondiagnostic samples. Nondiagnostic samples should be added to the NPV denominator because decisions based on nondiagnostic samples could be flawed. We Conservatively calculated NPV for EBUS-FNA as NPV=true negatives/true negatives + false negatives + nondiagnostic. We defined false negatives as negative FNAs but NSCLC-positive surgical biopsy of the same site. Nondiagnostic FNAs were nonrepresentative of lymphoid tissue. We compared diagnostic performance with the inclusion and exclusion of nondiagnostic procedures. Results We studied 120 patients with NSCLC who underwent EBUS-FNA; 5 patients had false negative findings and 10 additional patients had nondiagnostic results. The NPV with and without inclusion of nondiagnostic samples was 65.9% and 85.3%, respectively. Conclusions The inclusion of nondiagnostic specimens into the Conservative, worst-case-scenario Calculation of NPV for EBUS-FNA in NSCLC lowers the NPV from 85.3% to 65.9%. The true NPV is likely higher than 65.9% as few nondiagnostic specimens are false negatives. Caution is imperative for the safe application of EBUS-FNA in NSCLC staging.

Zhen Wang - One of the best experts on this subject based on the ideXlab platform.

  • feasible region of post tensioning force for precast segmental post tensioned uhpc bridge columns
    Engineering Structures, 2019
    Co-Authors: Zhen Wang, Jingquan Wang, Kejian Chen, Jian Zhang
    Abstract:

    Abstract This paper aims to establish an analytical method to determine the feasible region of post-tensioning (PT) force for precast segmental post-tensioned ultra-high performance concrete (UHPC) bridge columns. Three principles, i.e. no collapse after earthquake, good self-centering capacity, and no shear failure at joints, were put forward to define the feasible region of PT force according to the ultimate state. A Calculation procedure was developed to determine the ultimate state and verified by a validated finite element model. With the ultimate state known, an analytical method was established to calculate the feasible region of PT force according to the three principles. Parametric analysis was conducted to quantitatively study the effects of eight common design parameters on the feasible region of PT force. A noniterative Calculation method was further given to determine the feasible region of PT force for designers. The results show that the Calculation procedure can accurately predict the characteristic values at the ultimate state. There are significant effects of the eight design parameters on the feasible region of PT force, which is actually controlled by the two former principles. The gravity loading can provide sufficient shear resistance at joints without shear keys in general. The feasible region of PT force is mainly distributed between 0.10 and 0.20 for precast segmental UHPC bridge columns with an area ratio of energy dissipation (ED) bars of more than 1.00%. The feasible region of PT force does not exist when the ED bar ratio is more than a critical value (i.e., 2.83% in this research). A noniterative and Conservative Calculation method to determine the feasible region of PT force can be obtained when the compression zone height of the bottom section at the ultimate state is equal to the wall thickness of the hollow section.