: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Reactive oxygen species

AIE-based luminescence probes for metal ion detection

Recent progress in hydrogen sulphide (H2S) sensors by metal displacement approach

Starch and flour properties of different Indian durum wheat varieties were evaluated and related to noodle-making properties. Flours were evaluated for pasting properties, protein characteristics (extractable as well as unextractable monomeric and polymeric proteins) and dough rheology (farinographic properties), while starches were evaluated for granule size, thermal, pasting, and rheological properties. Flour peak and final viscosities related negatively to the proportion of monomeric proteins but positively to that of polymeric proteins whereas opposite relations were observed for dough rheological properties (dough-development time and stability). Starches from varieties with higher proportion of large granules showed the presence of less stable amylose-lipids and had more swelling power, peak viscosity and breakdown viscosity than those with greater proportion of small granules. Noodle-cooking time related positively to the proportion of monomeric proteins and starch gelatinization temperatures but negatively to that of polymeric proteins and amylose content. Varieties with more proteins resulted in firmer noodles. Noodle-cohesiveness related positively to the proportion of polymeric proteins and amylose-lipids complexes whereas springiness correlated negatively to amylose content and retrogradation tendency of starches.

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Physicochemical and rheological properties of starch and flour from different durum wheat varieties and their relationships with noodle quality

An intramolecular charge transfer (ICT) based fluorescent probe 2 has been designed and synthesized for the ratiometric detection of hydrazine in PC3 cell lines. Further, probe 2 demonstrates the selective naked-eye detection of hydrazine in the presence of representative metal ions in an aqueous environment. Further, to promote the selective, economic and easy detection of hydrazine, the fluorescent test strips of probe 2 have been prepared which can detect hydrazine up to femtogram level.

A charge transfer based ratiometric fluorescent probe for detection of hydrazine in aqueous medium and living cells

Relationship of various flour properties with noodle making characteristics among durum wheat varieties.

A new Alizarin Red S based fluorescent probe ARS–Zn(II) has been reported for the detection of H2S in aqueous buffer solution. In the presence of zinc ions, ARS displayed an increase in fluorescence intensity through the formation of an ARS–Zn(II) ensemble. The addition of H2S to the ensemble caused the disassembly of the metal and ARS, which restored the fluorescence intensity of ARS. This sensing ensemble exhibited H2S-selectivity over other biothiols and biologically relevant analytes. The calculated detection limit of ARS–Zn(II) with H2S was 92 nM. ARS–Zn(II) also detected H2S in serum under physiological conditions. Moreover, as a practical application, it could be used for the real time monitoring of H2S released from the H2S-donor molecule benzoic (methyl carbonic) dithioperoxyanhydride and also applied to live cell imaging. The reported ensemble ARS–Zn(II) has advantages like ready availability, high selectivity with good sensitivity, fast response time, higher excitation (520 nm) and emission (625 nm) wavelengths and real time fluorescence assay with H2S donors.

Alizarin red S–zinc(II) fluorescent ensemble for selective detection of hydrogen sulphide and assay with an H2S donor

Hexaphenylbenzene (HPB) appended rhodamine derivative 4 has been synthesized which exhibits aggregation-induced emission enhancement (AIEE) characteristics and forms fluorescent aggregates in mixed aqueous media. These aggregates show remarkable fluorescence resonance energy transfer (FRET) in the presence of Hg 2+ ions among various metal ions tested. Further these aggregates were also utilized for the ratiometric imaging of Hg 2+ ions in MCF-7 cell lines.

Hexaphenylbenzene appended AIEE active FRET based fluorescent probe for selective imaging of Hg2+ ions in MCF-7 cell lines

A rhodamine–phenanthroline dyad based fluorescent probe 4 has been designed and synthesized which selectively monitors Fe3+ ions among the various metal ions tested. Furthermore, probe 4 has been explored for monitoring of dynamic changes in the Fe3+ ion level under aggressive Fenton reaction conditions using a cell based model study. More significantly, probe 4 has also been utilized for real time imaging of endogenous Fe3+ ions in living C6 cell lines, the results of which demonstrated that probe 4 acts as an efficient fluorescent tool for Fe3+ ion detection in biological systems.

Davinder Kaur

Papers

A charge transfer based ratiometric fluorescent probe for detection of hydrazine in aqueous medium and living cells

Relationship of various flour properties with noodle making characteristics among durum wheat varieties.

Alizarin red S–zinc(II) fluorescent ensemble for selective detection of hydrogen sulphide and assay with an H2S donor

Hexaphenylbenzene appended AIEE active FRET based fluorescent probe for selective imaging of Hg2+ ions in MCF-7 cell lines

A highly selective fluorescent probe for Fe3+ in living cells: a stress induced cell based model study