Pyrene functionalized oxacalix[4]arene architecture as dual readout sensor for expeditious recognition of cyanide anion

A pyrene functionalized oxacalix[4]arene architecture (DPOC) was utilized as a fluorescence probe for selective recognition of cyanide ions. The receptor DPOC shows excellent selectivity towards cyanide ion with a red shift of 108 nm in absorption band along with a significant change in colour from light yellow to pink. The fluorescence titration experiments further confirm the lower limit of detection as 1.7µM with no significant influences of competing anions. ¹ H-NMR titration experiments support the deprotonation phenomena, as the -NH proton disappears upon successive addition of cyanide ions. The DFT calculation also indicates a certain increment of -NH bond length upon interaction with cyanide ions. The spectral properties as well as colour of DPOC-CN^? system may be reversed upon the addition of Ag⁺/ Cu²⁺ ions up to 5 consecutive cycles. Moreover, DPOC coated “test strips” were prepared for visual detection of cyanide ions.

     

Designing of LaCrO3 − TiO2 nanocomposites p: n heterojunction-based sensor material for the selective detection of volatile petrol vapors (PV) and CO2 gas vapors

In the present research TiO₂ modified LaCrO₃ nanostructure has been designed by simple sol-gel method. The thick films of TiO₂ with different concentrations with LaCrO₃ were fabricated by using screen printing methodology. In present study, the structural properties of TiO₂ doped LaCrO₃ were confirm by using X-ray diffractometer (XRD). While the morphological properties and surface characteristics of fabricated material analyzed using scanning electron microscopy (SEM). The energy dispersive spectroscopy (EDS) was utilized for chemical composition of the prepared material. Transmission electron microscopy (TEM) confirms the orthorhombic crystal lattice structure and morphology of Ti-doped LaCrO₃. While, Fourier transform infrared (FT-IR) spectroscopy was used to investigate the M ? O bonding vibrational stretching frequencies of LaCrO₃ and TiO₂ materials. The zeta potential was recorded for stability of all Ti doped LaCrO₃ nanostructures. The Brunauer-Emmett-Teller (BET) was analyzed for surface area and pore diameter parameters of the fabricated materials. The fabricated materials were checked for application as a sensor for different pollutant gases like Ethanol, CO₂, NO₂, and petrol vapors. The sensor demonstrates the sensitivity for petrol vapors at 150°C for 0.3 M% TiO₂ doped LaCrO₃. And exceptionally 0.5 M% TiO₂ doped LaCrO₃ sensor showed better response for CO₂. The reproducibility confirms the stability of 0.3 M % TiO₂ doped LaCrO₃ sensor and 0.5 M % TiO₂ doped LaCrO₃ sensor. The rapid response and recovery were recorded for both the sensors viz. 0.3 M % and 0.5 M % TiO₂ doped LaCrO₃.     

A solution algorithm for non-convex mixed integer optimization problems with only few continuous variables

Geometric branch-and-bound techniques are well-known solution algorithms for non-convex continuous global optimization problems with box constraints. Several approaches can be found in the literature differing mainly in the bounds used.     

Synthesis,structure and biological activity of new 6,6‐dimethyl‐2‐oxo‐4‐{2‐[5‐organylsilyl(germyl)]furan(thiophen)‐2‐yl}vinyl‐5,6‐dihydro‐2H‐pyran‐3‐carbonitriles

New 6,6‐dimethyl‐2‐oxo‐4‐{2‐[5‐alkylsilyl(germyl)]furan(thiophen)‐2‐yl}vinyl‐5,6‐dihydro‐2H‐pyran‐3‐carbonitriles (IC₅₀: 1–6 µg ml^?1) have been prepared by the condensation of corresponding silicon‐ and germanium‐containing furyl(thienyl)‐2‐carbaldehydes with 3‐cyano‐4,6,6‐trimethyl‐5,6‐dihydropyran‐2‐one using piperidine acetate as a catalyst. The obtained carbonitriles were identified using NMR (¹H, ¹³C and ²⁹Si) spectroscopy and GC‐MS. The structure of 6,6‐dimethyl‐2‐oxo‐4‐[2‐(5‐trimethylsilyl)thiophen‐2‐yl]‐5,6‐dihydro‐2H‐pyran‐3‐carbonitrile was studied using X‐ray diffractometry. The influences of the heterocycle and the structure of the organoelement substituent on cytotoxicity and on matrix metalloproteinase inhibition have been studied. Copyright © 2015 John Wiley & Sons, Ltd.     

A new type of electrohydrodynamic instability in nematic liquid crystals with positive dielectric anisotropy

Abstract

A new type of electrohydrodynamic instability originally reported in nematic liquid crystal mixtures with positive dielectric anisotropy and as moderately thick samples is further studied. The ability of homogeneously aligned nematics with positive dielectric anisotropy, in the presence of a magnetic field, to exhibit Williams domains as a threshold effect is numerically investigated. The variation of the threshold voltage for domain formation and dielectric alignment with dielectric anisotropy is calculated theoretically and compared with the experimental results as moderately thick and thin samples.