Fluoride triggered fluorescence "turn on" sensor for Zn2+ ions based on pentaquinone scaffold that works as a molecular keypad lock

A pentaquinone based compound 3a has been synthesized which exhibits pronounced fluorescence enhancement in the presence of Zn(2+) ions under a F(-) triggered synergistic effect. Derivative 3a also behaves as a molecular keypad lock with sequential chemical inputs of Zn(2+) and F(-) ions.     

Two new 14-membered cyclopeptide alkaloids from Zizyphus xylopyra

The phytochemical investigation of the bark of Zizyphus xylopyra resulted in the isolation of two new 14-membered ring cyclopeptide alkaloids, xylopyrine-G and xylopyrine H. Their structures have been established by chemical and spectral evidences.     

Triphenylene based copper ensemble for the detection of cyanide ions

The binding behavior of triphenylene based copper ensemble prepared in situ has been investigated toward various anions (F(-), Cl(-), Br(-), I(-), CH(3)COO(-), H(2)PO(4)(-), NO(3)(-), OH(-), ClO(4)(-), CN(-), CO(3)(-) and SO(4)(-)) by UV-vis and fluorescence spectroscopy. Among various anions tested, 1-Cu(2+) ensemble shows selective and sensitive response towards cyanide ions and responds to CN(-) ions even in the presence of bovine serum albumin and in blood serum milieu. Further, as practical application of compound 1, we utilized the TLC strips coated with THF solution of 1 for the solid state detection of copper and cyanide ions.     

Solution-phase detection of dual microRNA biomarkers in serum

A strategy for the simultaneous detection of multiple microRNA (miRNA) targets was developed utilizing fluorophore/quencher-labeled oligonucleotide probe sets. Two miRNA targets (miR-155 and miR-103), whose misregulation has afforded them status as putative biomarkers in certain types of cancer, were detected using our assay design. In the absence of target, the complementary fluorophore-probe and quencher-probe hybridize, resulting in a fluorescence resonance energy transfer-based quenching of the fluorescence signal. In the presence of unlabeled target, however, the antisense quencher-probe can hybridize with the target, resulting in increased fluorescence intensity as the quencher-probe is sequestered beyond the Förster radius of the fluorescent-probe. The assay design was tested in multiple matrices of buffer, cellular extract, and serum; and detection limits were found to be matrix-dependent, ranging from 0.34 to 8.89 pmol (3.4–59.3 nM) for miR-155 and 2.90–11.8 pmol (19.3–79.0 nM) for miR-103. Single, double, and triple nucleotide selectivity was also tested. Additionally, miR-155 concentrations were assessed in serum samples obtained directly from breast cancer patients without the need for RNA extraction. This assay is quantitative, possesses a low detection limit, can be applied in multiple complex matrices, and can obtain single-nucleotide selectivity. This method can be employed for the multiplex detection of solution-phase DNA or RNA targets and, more specifically, for the direct detection of serum miRNA biomarkers.     

Thiacalix[4]arene based fluorescent probe for sensing and imaging of Fe3+ ions

A thiacalix[4]arene based fluorescent chemosensor 3 in the cone conformation has been synthesized and its recognition behaviour is evaluated toward various metal ions in mixed aqueous media. The chemosensor 3 showed high selectivity towards Fe(3+) ions by fluorescence quenching of excimer emission. Further, evaluation of the 3·Fe(3+) complex prepared in situ demonstrated great promise for the detection of the Fe(3+) ion in the presence of amino acids, blood serum and bovine serum albumin (BSA) solution. The compound 3 has suitable permeability into the PC3 cells and can be utilized as a Fe(3+) selective sensor in living cells (PC3 cells).     

Numerical Algorithm Based on Quintic Nonpolynomial Spline for Solving Third-Order Boundary Value Problems Associated with Draining and Coating Flows

A numerical algorithm is developed for the approximation of the solution to certain boundary value problems involving the third-order ordinary differential equation associated with draining and coating flows. The authors show that the approximate solutions obtained by the numerical algorithm developed by using nonpolynomial quintic spline functions are better than those produced by other spline and domain decomposition methods. The algorithm is tested on two problems associated with draining and coating flows to demonstrate the practical usefulness of the approach.     

Role of Vitamins B-3 and C in the Fashioning of Granules in UASB Reactor Sludge

Whereas a myriad of possible factors have been reported which effect the formation of granules in a upflow anaerobic sludge blanket (UASB) reactor and influence their properties, there is no study on the effect of vitamins on the granulation of UASB reactor sludge. The present study was undertaken to bridge this gap. It was seen that vitamins helped in better granule formation??as reflected by favorable size distribution, sludge volume index, and settling velocity??compared to controls. The vitamin-spiked reactors also achieved >85?% COD removal efficiency in half the number of days the unspiked reactors took. The vitamin supplements were effective at concentrations????1?mg/l. Hence, their use in expediting granule formation as also in developing better-quality granules appears economically viable.     

Microwave-assisted synthesis of 1,3-dialkyl ethers of calix[4]arenes: application to the synthesis of cesium selective calix[4]crown-6 ionophores

Partial etherification of phenolic-OH groups of calix[4]arenes with various alkyl halides/tosylates and K₂CO₃ under microwave irradiation afforded 1,3-dialkoxycalix[4]arenes in their cone conformation only as predominant/sole product in good yields (71–85%). The protocol was found to be much superior to conventional heating both in terms of yield and reaction time. Some of the 1,3-dialkoxycalix[4]arenes were elaborated further to the syntheses of cesium selective calix[4]crown-6 ionophores.     

Effect of doping concentration and annealing temperature on luminescence properties of Y2O3:Eu3+ nanophosphor prepared by colloidal precipitation method

Eu³⁺ doped Y₂O₃ nanophosphors have been synthesized using the simple colloidal precipitation method. Doping of Eu³⁺ ions in host yttria lattice has been achieved through slow re-crystallization process under wet-chemical conditions followed by annealing at high temperatures (300–1400 °C). The nanophosphors were characterized by using powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), atomic force microscopy (AFM) and spectrofluorometer techniques. XRD analysis reveals formation of pure cubic phase of Y₂O₃ in samples annealed at 700 °C or above. Further, the XRD data was successfully used to retrieve the crystallite size and size distribution from powder samples using the FW((1/5)/(4/5))M method. Crystallite size (11–50 nm) extracted from XRD has been found to be consistent with AFM measurements. The PL emission spectra of nanophosphors show bright red emission at 612 nm due to hypersensitive electric dipole (ED) ⁵D₀–⁷F₂ transition of Eu³⁺ ions in Y₂O₃ lattice. Further, photoluminescence studies indicate that optimum value of the Eu³⁺ to get best luminescence properties is 12 at%. Surface conjugations of these nanophosphors with water soluble dextran biomolecules have also been performed. Surface conjugated rare earth nanophosphors have great potential for bio-applications.