cules 1b-4 and 1b-5 as the prototype of optimized nonlinearity-stability-solubility characteristics, whereby a typical mb value of 22 000 10 ±48 esu is found for molecule 1b-5). This opens an interesting route to poled materials for electrooptic-modulation and photorefractive applications. [32,33] The results also demonstrate that the cubic polarizabilities increase much more with conjugated length compared to quadratic polarizabilities, leading to enhanced cubic nonlinearities (up to g(0) values of about 7400´10 ±36 esu). In addition, the present work emphasizes the challenging potential of new engineering routes towards the optimization of materials with large cubic nonlinearities via increasing the magnitude of the g peaks. ExperimentalPolyenals of the series 1a and 2a were obtained from the corresponding generic aldehydes via a sequential protocol based upon Wittig oxyprenylation followed by acidic hydrolysis [9]. The synthesis of push-pull derivatives 1±2,b±c was carried out by reacting 1a-n (or 2a-n) with one equivalent of malonodinitrile (or methylrhodanine) in refluxing ethanol. After evaporation of the solvent, the crude compounds were purified by column chromatography and recrystallization. Pure all-trans compounds were obtained as assessed by NMR, elemental analyses, and mass spectrometry. The DSC records were recorded in air using a Perkin-Elmer DSC 7 microcalorimeter. CV was performed using a classical three electrodes cell as described in the literature [9].Dipole moments were obtained from dielectric and refractive index measurement performed in dry toluene as carried out in the literature [9], except in the case for molecules of the series 2b,c, for which m values derived from electrooptical measurements were used [20]. EFISH measurements were carried out using the experimental protocol and quartz reference described in the literature [9]. The experimental accuracy ranges between 5 and 10 %. For each molecule THG experiments were conducted using solutions of five different concentrations in chloroform and the experimental protocol described in the literature [34]. The measurements were calibrated relative to fused silica for which a w 3 value of 2.8´10 ±14 esu (3.9´10 ±22 m 2 V ±2 ) was used [35]. The experimental accuracy amounts to 5 %.

Scalable production of high-quality MoS 2 nanosheets remains challenging for industrial applications and research in basic sciences. N-methyl-2pyrrolidine (NMP) is a commonly used solvent for exfoliation of MoS 2 nanosheets having further disadvantage of slow volatility rate. The present study demonstrates a cost-effective facile chemical route to synthesize few-layer MoS 2 nanosheets using acetone as a solvent and by varying bulk initial concentration of samples to scale up the production in large scale to fulfill the demand for potential applications. In our study, we aim to obtain stable growth of high quality few layer MoS 2 nanosheets by long sonication times. Optical absorption spectra, Raman spectra, size of nanosheets and layer thickness of as-grown MoS 2 nanosheets were found to be matching with those obtained from other synthesis methods. Effective photocatalytic performance of MoS 2 nanosheets without being consumed as a reactant was experimented by decomposing Methylene Blue dye in aqueous solution under irradiation of visible light. This study provides an idea to synthesize low-cost, sustainable and efficient photocatalytic material in large scale for the next generation to control water pollution quite efficiently by protecting the environment from the contamination coming from these dyes.

Measurements of DNA conductivity, hybridization, and melting using electronic means can have wide applications in molecular electronics and biological sensors. We have fabricated nanogap break-junctions by electromigration through thin gold-on-titanium films. 18-mer thiolated ds-DNA molecules were covalently attached between the electrodes and dc electrical measurements were done. The conductance was measured through the molecule before and after a temperature ramp from 300 to 400 K. A dramatic decrease in conductance was observed, analogous to an electrical fuse, possibly attributed to complete or partial denaturing of the ds-DNA molecules bridging the nanogaps. We also show evidence that the dc resistance of dry DNA strands of the same length decreases with increasing guanine-cytosine content in the sequence with values ranging from 10 M Ω to 2 G Ω. These findings can have important consequences in DNA-based molecular electronics and direct label-free detection of DNA hybridization.

A new SET-driven reaction-based strategy is reported for sensing of cyanide with indicators having low LUMO levels. The cyanide-specific reaction produces an air-stable radical anion marker and by virtue of its spin, charge, and the SOMO-LUMO-based electronic transition generates multimodal signal outputs. High selectivity and sensitivity (0.2-16 microM) were observed when compared to other reducing anions. This new indicator system exhibits regenerability and dip-stick sensing, and fabrication of an electronic sensing device for cyanide is demonstrated.

Band gap engineering offers tunable optical and electronic properties of semiconductors in the development of efficient photovoltaic cells and photocatalysts. Our study demonstrates the band gap engineering of ZnO nanorods to develop a highly efficient visible-light photocatalyst. We engineered the band gap of ZnO nanorods by introducing the core/shell geometry with Ag2S sensitizer as the shell. Introduction of the core/shell geometry evinces great promise for expanding the light-harvesting range and substantial suppression of charge carrier recombination, which are of supreme importance in the realm of photocatalysis. To unveil the superiority of Ag2S as a sensitizer in engineering the band gap of ZnO in comparison to the Cd-based sensitizers, we also designed ZnO/CdS core/shell nanostructures having the same shell thickness. The photocatalytic performance of the resultant core/shell nanostructures toward methylene blue (MB) dye degradation has been studied. The results imply that the ZnO/Ag2S core/shell nanostructures reveal 40- and 2-fold enhancement in degradation constant in comparison to the pure ZnO and ZnO/CdS core/shell nanostructures, respectively. This high efficiency is elucidated in terms of (i) efficient light harvesting owing to the incorporation of Ag2S and (ii) smaller conduction band offset between ZnO and Ag2S, promoting more efficient charge separation at the core/shell interface. A credible photodegradation mechanism for the MB dye deploying ZnO/Ag2S core/shell nanostructures is proposed from the analysis of involved active species such as hydroxyl radicals (OH(•)), electrons (e(-)(CB)), holes (h(+)(VB)), and superoxide radical anions (O2(•-)) in the photodegradation process utilizing various active species scavengers and EPR spectroscopy. The findings show that the MB oxidation is directed mainly by the assistance of hydroxyl radicals (OH(•)). The results presented here provide new insights for developing band gap engineered semiconductor nanostructures for energy-harvesting applications and demonstrate Ag2S to be a potential sensitizer to supersede Cd-based sensitizers for eco-friendly applications.

Nanorods of zinc oxalate dihydrate have been synthesized using the reverse micellar route. These nanorods were decomposed at 450 °C in air to obtain nanoparticles of zinc oxide. Transmission electron microscopy shows the nanorods to be 120 nm in diameter and 600 nm in length. The ZnO nanoparticles are 55 nm in diameter. The photoluminescence studies show two peaks at 370 and 403 nm which can be ascribed to free excitonic transition and donor–acceptor pair transition respectively. The temperature dependent PL intensity shows an anomalous non-monotonous temperature dependence probably due to two different optical processes.

Using a multi-institutional Indian registry, this study is the first to systematically document that the 30-day in-hospital trauma mortality was twice that found in similar registries from high-income countries. Physiological scoring of on-admission vitals was clinically useful to predict mortality. More research is needed to understand the causes of high mortality and time delays in the process of delivering trauma care in India, which has no prehospital or trauma system.

Conformations and charge transport characteristics of biphenyldithiol self-assembled-monolayer molecular electronic devices: A multiscale computational study Theoretical investigation on electron transport through an organic molecule: Effect of the contact structure