We report a visual chronometric assay for Cr based on the CuO nanocube-mediated clock reaction of methylene blue (MB) and NH. MB with a blue color can be easily reduced by excess NH to form colorless leuco-MB in the presence of CuO nanocubes as a catalyst in a short time. However, the addition of Cr decreases the catalytic activity of CuO nanocubes owing to the coordination interactions between them, leading to an increase in the reaction time. The reaction time change was employed for selective detection of Cr. This assay has a wide dynamic range from 0.03 to 600 μM with a limit of detection of 2.7 nM. Remarkably, different concentrations of Cr can be directly detected with the naked eye by observing the color-fading speed. Additionally, this assay was successfully used to determine Cr in real water samples.
Background: Transbronchial needle aspiration (TBNA) is a classical technique for diagnosing mediastinal-hilar lymph node enlargement. However, the diagnostic value of conventional TBNA (cTBNA) is limited in small lymph nodes.Methods: Here, we generated an innovative multi-dimensional virtual lymph node map on top of Wang’s lymph node map using a Lungpoint Virtual Bronchoscopic Navigation System.Results: The virtual bronchoscopic navigation (VBN) system was combined with computed tomography (CT) images to generate extrabronchial, endobronchial, sagittal, coronal as well as horizontal views of the 11 intrathoracic lymph node stations and their adjacent tissues and blood vessels. We displayed the specific puncture site of each lymph node station. The 11 stations were divided into four groups: right mediastinal stations, left mediastinal stations, central mediastinal stations and hilar stations.Conclusion: The VBN system provides a precise view of the intrabronchial landmarks, which may increase the diagnostic accuracy of intrathoracic lymph node adenopathy and assist bronchoscopists with practicing TBNA.
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