Inorganic phosphate regulated high luminescence NaYF4:Yb3+, Er3+ as an iron ion fluorescent nanoprobe.

The iron ion in industrial circulating cooling water is an important indicator for early warning of equipment corrosion and control level. It is interesting to construct an upconversion luminescence iron ion nanoprobe with a common inorganic phosphate water treatment agent. Herein, inorganic phosphate sodium hexametaphosphate (SHMP) was used to regulate the morphology and functionalization of NaYF4:Yb3+, Er3+ upconversion luminescent nanoprobe (UCNPs) and applied to fluorometric detection of trace Fe(III) in water based on the fluorescence quenching which is caused by the selective coordination between hexametaphosphate on the surface of UCNPs and Fe(III). The structure, morphology, and luminous intensity of UCNPs were regulated by disodium hydrogen phosphate (ADSP), sodium tripolyphosphate (STPP) and sodium hexametaphosphate(SHMP). The UCNPs functionalized with SHMP has high sensitivity and selectivity for Fe(III) detection. The linear range and detection limit are 1.0-50 µM and 0.2 µM, respectively. The method has satisfactory results for the detection of trace Fe(III) in industrial circulating cooling water.

Three-dimensional gold nanowires with high specific surface area for simultaneous detection of heavy metal ions.

Traditional detection methods to detect heavy metal ions are time-consuming, complicated, and expensive. Here, we developed a simple electroless plating method to prepare three-dimensional gold nanowire (Au NW) films with high specific surface area. In an aqueous plating bath, tetrachloroauric acid, 4-dimethylaminopyridine and formaldehyde are used as precursor, ligand, and reducing agent, respectively. An electrochemical sensor based on a Au NWs/SPE could be applied for simultaneous detection of lead (Pb(II)), arsenic (As(III)), and mercury (Hg(II)) ions. The detection limits of Pb(II), As(III), and Hg(II) are 2.6, 1.5, and 4.2 µg L-1, all lower than the permissible limits of the WHO for drinking water (the permissible level of Pb(II) and As(III) is 10.0 µg L-1, and the permissible level of Hg(II) is 6.0 µg L-1), respectively. This work presents a simple and novel method to prepare gold nanowires for quick detection of trace heavy metal ions.

Electrochemical Intermolecular Monofluoroalkylation of α,ß-Unsaturated Carboxylic Acids and Heteroaromatics with 2-Fluoromalonate Esters.

An electrochemical approach for the preparation of monofluorides from α,ß-unsaturated carboxylic acids and heteroaromatics with readily available 2-fluoromalonate esters as monofluoroalkyl radical precursors has been developed. The electrosynthesis employs ferrocene (Cp2Fe) as a catalyst in a simple undivided cell with a broad substrate scope, which obviates the need for sacrificial oxidizing reagents.

Correlation between intracranial vertebral artery stenosis diameter measured by digital subtraction angiography and cross-sectional area measured by optical coherence tomography.

BACKGROUND: Intracranial vertebral artery (V4 segment) stenosis quantification traditionally uses the narrowest stenosis diameter. However, the stenotic V4 lumen is commonly irregularly shaped. Optical coherence tomography (OCT) allows a more precise calculation of V4 geometry. We compared the narrowest diameter stenosis (DS), measured by digital subtraction angiography (DSA), with the area stenosis (AS), measured by OCT. We hypothesized that DS is the gold standard for measuring the degree of stenosis. METHODS: Five neuroradiologists evaluated 49 stenosed V4 segments in a blinded protocol. V4 stenosis was measured in millimeters on DSA at its narrowest diameter. OCT was used to estimate the cross-sectional luminal area. We also used automated software to measure DS. Three different angles (anterior, lateral, and oblique views) were used for calculations, and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) methods were used in all measurements. Spearman's R values were calculated. Non-linear regression analysis was performed between the DS and AS, with statistically different correlations. RESULTS: A high correlation was observed between the WASID and NASCET methods to measure DS with observer measurement and automated software. A good correlation was found between DS measured by observers and AS measured by OCT. Non-linear regression analysis showed that only observer measurement using the oblique view and the WASID method could attain statistically significant differences, but it was weak (r=0.389). CONCLUSION: Measurement of the narrowest diameter was not a reliable predictor of the cross-sectional area of V4 stenosis. Larger studies are therefore needed to develop a new evaluation system based on V4 stenosis.