‘On-Off’ reversible switch for Fe and F mimicking XNOR logic function

A new pyrene-appended chemosensor based on thiacalix[4]arene of 1,3-alternate conformation has been synthesised which demonstrates selective optical recognition of Fe³⁺ and F⁻ in two contrasting modes. The chemosensor behaves as a bifunctional fluorescent switch which mimics the performance of an exclusive-NOR (XNOR) logic gate with chemical inputs of Fe³⁺ and F⁻ ions.     

Sample complexity reduction aids efficient detection of low‐abundant proteins from human amniotic fluid

Working with biological fluids poses a challenge of visualizing proteins present in lower concentrations. This study describes a batch‐mode chromatographic method for the fractionation of human amniotic fluid (AF). This method is easy to use with minimal sample quantity, resin volume and sample processing time. For albumin depletion, two methods were evaluated. The results demonstrated that specific depletion of albumin, using affinity‐ligand‐based resin, is more efficient than the conventional dye‐based method. The albumin‐depleted human AF was fractionated by strong anion‐exchange resin in spin devices, for sample, complexity reduction and enrichment of low‐abundant proteins. Analysis of four eluate fractions generated after this step shows enrichment of few low‐abundant proteins. Two novel low‐abundant proteins, Rab GDP dissociation inhibitor β and peptide methionine sulfoxide reductase, were identified from human AF. α‐1‐B Glycoprotein was successfully identified by this strategy, whereas the published literature reports that it was not identified by strong anion‐exchange FPLC followed by SDS‐PAGE. Therefore, the current method has distinct advantages over the conventional column‐based chromatography. This study also reports altered expression of some proteins in Rh‐isoimmunized AF samples in comparison with normal AF.     

Dielectric relaxation behavior of C5+ (70 MeV) swift heavy ion irradiated polyetheretherketone (PEEK) using TSDC technique

The dielectric relaxation characteristics of polyetheretherketone (PEEK) irradiated with C⁵⁺ (70 MeV) ion, have been investigated in the temperature range 60–230° as a function of poling temperature T _P (50, 100, 150, and 200°C), poling field E _P (200, 300, 400, and 500 kV/cm), and storage time t _s (2, 24, 48, and 120 h), using thermally stimulated discharge current (TSDC) technique. The TSDC spectra show a prominent maximum around glass transition temperature (T _g ～ 143°C) named as α-peak. This peak is attributed to the movement of ketone dipoles linked with the main chain. It is observed that the magnitude of α-peak increases with the increase in poling temperature and poling field. The peak current and area under the α-peak are found to be diminished with the increase of storage time t _s for electrets. The β-peak (space charge peak) is absent in irradiated PEEK samples as compared to pristine PEEK samples. The results obtained, in the present studies, are compared with the results on pristine samples. The activation energies and pre-exponential factor for PEEK samples determined using Bucci plot method.     

Monoclinic zirconia nanoparticle-catalyzed regioselective synthesis of some novel substituted spirooxindoles through one-pot multicomponent reaction in a ball mill: A step toward green and sustainable chemistry

A highly efficient, green as well as atom economical protocol for the synthesis of substituted spirooxindoles from m-ZrO₂ NPs catalyzed multicomponent reaction of isatin derivatives with ethyl cyanoacetate and 1,3-dicarbonyl compounds in a ball mill has been established. Because of the simple and readily available starting materials, easy operation, and high bioactivity of substituted spirooxindoles, this strategy can be broadly applied to medicinal chemistry. The recyclability of the m-ZrO₂ Nps catalyst is another emphasis of proposed methodology.     

An efficient method for the synthesis of methyl 11α-amino-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate

The synthesis of methyl 11α-azido-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate, methyl 11β-azido-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate and methyl 11α-amino-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate have been achieved. Mechanistic aspects for the decomposition of steroidal azidoketones to its enamines are discussed.     

Synthesis and binding studies of novel bisthiacalix[4]arenes with diimime linkages

A series of novel bisthiacalix[4]arenes with diimine linkages of different aromatic or heteroaromatic dialdehydes have been synthesized. The structure of one of the bisthiacalixarene has been analyzed by X-ray crystallography. These molecules quantitatively extract silver ion from aqueous into organic phase under neutral conditions.     

Role of the vortex-core energy on the Berezinskii-Kosterlitz-Thouless transition in thin films of NbN

We analyze the occurrence of the Berezinskii-Kosterlitz-Thouless (BKT) transition in thin films of NbN at various film thickness, by probing the effect of vortex fluctuations on the temperature dependence of the superfluid density below T(BKT) and of the resistivity above T(BKT). By direct comparison between the experimental data and the theory, we show the crucial role played by the vortex-core energy in determining the characteristic signatures of the BKT physics, and we estimate its dependence on the disorder level. Our work provides a paradigmatic example of BKT physics in a quasi-two-dimensional superconductor.     

Fluoride-induced cyclization of pentacenequinone to higher quinones

Novel pentacenequinone derivatives 3, 7, and 10 have been synthesized via Suzuki-Miyaura coupling. Derivatives 3 and 7 having OTBS groups undergo irreversible fluoride-induced cyclization to substituted higher quinones in the presence of TBAF in dry THF using one-pot, two-step strategies in moderate yields. These functionalized higher quinone derivatives are freely soluble in THF and DMSO and can be used as precursors for the synthesis of higher acene derivatives.