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Given that hexavalent chromium ions (Cr(VI)) are among the most biologically toxic heavy metal ions in the environment, it would be desirable to develop approaches that are easy-to-use, practical, and cost-effective for monitoring Cr(VI) content in environmental matrices. Herein, we report a colorimetric assay for Cr(VI) detection based on the oxidase-like activity of a series of nanoscale substituted transition metal vanadates (STMVs) with the general formula M3V2O8, where M represents divalent metal cations such as Ni2+, Cu2+, and Zn2+. The structural and physicochemical characterisations indicated that mesoporous Cu3V2O8 and Ni3V2O8 with roughly nano-spherical morphologies were successfully formed with monoclinic and orthorhombic phases, respectively. In addition, micro/mesoporous Zn3V2O8 had uniform hexagonal nanosheets with an orthorhombic crystalline phase. The UV-vis spectroscopy showed that Cu3V2O8 and Ni3V2O8 oxidised O-phenylenediamine (OPD) to 2,3-diaminophenazine (DAP); however, Zn3V2O8 did not exhibit the desired activity. Under the optimised reaction conditions, a simple, fast, and low-cost colorimetric sensor was designed based on the outstanding oxidase-like activity of Cu3V2O8 (Vmax = 0.25 µM s−1) to detect Cr(VI). The Cu3V2O8/OPD system operated selectively for Cr(VI) against other ions, and the lowest detectable [Cr(VI)] within the linear range of 2–32 μM was 0.24 μM, which is lower than the standard Cr(VI) levels (0.96 µM) for drinking water set by the World Health Organisation (WHO). This colorimetric technique was also applicable for assessing Cr(VI) in untreated tap water and Caspian Sea water samples. The analytical results showed that mesoporous Cu3V2O8 reliably developed a sensitive colorimetric system with thermal stability for the determination of toxic ions in water sources based on an intrinsic oxidase mimic. [ABSTRACT FROM AUTHOR]

Ammonium iron (II) sulfate hexahydrate [(NH4)2Fe(SO4)2 · 6H2O] as a nondurable finish was deposited onto cotton fabric, and its uniformity was ensured by means of squeeze rolls. By using a vertical flame test the optimum add-on values to impart flame-retardancy to the fabric was determined to be about 23.62-25.82%. The XRD analysis of ashes of impregnated samples showed the existence of iron (III) oxide. Hence it can plausibly be deduced that a reduction-oxidation reaction occurred during the combustion of the treated specimens and other elements presented in the aforementioned salt and converted to gaseous products, that is, SO2, H2O, CO2, and NH3, were eliminated during the combustion process. Hence "Gas theory" could play a significant role in justifying its flame-retardancy action. On the other hand, the presence of Fe2O3 dust in the consumed ashes proves the Dust or Wall effect suggested by Jolles and Jolles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Probe NPAMQ was used for quantitative and qualitative analysis of Cu2+ ions in foodstuff and water samples. • The LOD was calculated to be 81.49 nM for Cu2+ ions. • The density functional theory (DFT) calculations were performed for NPAMQ and NPAMQ-Cu2+. A novel molecular chemosensor (E)-5-(2-(4-nitrophenyl) azo)-2-methylquinolin-8-ol (NPAMQ) was synthesized and characterized by FT-IR, UV–Vis, 1H NMR, 13C NMR, and TGA. The sensing ability of NPAMQ towards several cations and anions was evaluated by UV–Vis absorption spectroscopy and naked-eye detection. The chemosensor NPAMQ displayed a distinct color change (from yellow to red) towards Cu2+ ions in less than a hundredth of a second, which is easily recognized by the naked eye. UV–Vis spectroscopic studies also proved a bathochromic shift (lower energy) in absorption spectra of NPAMQ in the presence of Cu2+ ions due to the formation of the stable complex NPAMQ-Cu2+. The NPAMQ showed a linear response toward Cu2+ ions (0–50 μM) with detection limits (LOD) of 81.7 nM (0.0197 mg/L). Job's plot showed formation of a complex between Cu2+ ions and chemosensor NPAMQ (NPAMQ-Cu2+ complex) which reveals presence of a stoichiometric ratio of 1:1. Moreover, the binding constant of the NPAMQ-Cu2+ complex was measured to be 3.07 × 104 M−1. NPAMQ can be easily recycled using EDTA and reused for over 5 times preserving a high level of detection efficiency. For better understanding the optical characteristics of the sensor, density functional theory (DFT) calculations were performed for NPAMQ and NPAMQ-Cu2+. Furthermore, the chemosensor NPAMQ was applied for the quantitative and qualitative analysis of Cu2+ ions in foodstuff and water samples. The paper test strips containing NPAMQ chemosensor were also fabricated and applied for detection of Cu2+ ions in aqueous solutions. This designed sensor with great features like cost-effective, short response times, excellent selectivity and sensitively can be used at different pH for detection of copper ions in industrial and biological samples. [ABSTRACT FROM AUTHOR]

The cancer immunotherapy method uses the specificity of the immune system to provide a more effective than more conventional treatments, such as chemotherapy and radiotherapy. Immunotherapy has two main strategies (passive or active) to organize the immune system. Passive strategies use advantage of tumor-hyperpermeable cells, which have enhanced permeability and retention effects. Nanoparticles due to their better accumulation within tissues and cells of the immune system are well suitable for delivery of immune therapies such as vaccines or adjuvants. In this review, we explained application of nanotechnology in immunotherapy of cancer. [ABSTRACT FROM AUTHOR]