Reactions of a,ß‐unsaturated N‐benzenesulfonyl Imine – N‐[(2E)‐3‐phenyl‐2‐propen‐1‐ylidene]benzenesulfonamide with Methyllithium

α,β‐Unsaturated N‐benzenesulfonyl imine 1 was treated with 1.1 eq methyllithium to afford 1,2‐addition adduct as a sole product. However, when compound 1 was treated with 2 eq MeLi, 1,2‐addition product, benzenesulfonamide derivative 3 and 2H‐1,2‐benzothiazine 1,1‐dioxide derivatives 4 and 5 were isolated.     

Chitosan-based self-healing hydrogel for bioapplications

A chitosan-based biocompatible self-healing hydrogel has been facilely prepared and used for bioapplications.     

On the Stability and Solution Sensitivity of a Consumer Problem

We present a continuous-time generalization of the seminal research and development model of d’Aspremont and Jacquemin (Am Econ Rev 78(5):1133–1137, 1988) to examine the trade-off between the benefits of allowing firms to cooperate in research and the corresponding increased potential for product market collusion. We show the existence of a solution to the optimal investment problem using a combination of results from viscosity theory and the theory of planar dynamical systems. In particular, we show that there is a critical level of marginal cost at which firms are indifferent between doing nothing and starting to develop the technology. We find that colluding firms develop further a wider range of initial technologies, pursue innovations more quickly, and are less likely to abandon a technology. Product market collusion could thus yield higher total surplus.     

Distance‐dependent Enhancement in Raman Spectroscopy Probed by Conjugated Molecules with Different Molecular Lengths

In this study, the distance‐dependent enhancement effect in surface‐enhanced Raman scattering (SERS) was explored with molecules bearing different lengths of conjugated double bonds. These conjugated molecules were synthesized utilizing the diazotization‐coupling reaction allowing a thio group on one end and a nitro group on the other end. The thiol group allows the probed molecule to chemisorb on the surface of silver nanoparticles (AgNPs). The opposite end of each molecule contains a nitro group, which gives an intense SERS signal to show a fair and accurate comparison of the effect of chain length. The obtained SERS intensities were correlated with the chain lengths of these synthesized molecules, which ranged from 0.6 to 2.0 nm between the nitro and thiol groups. Based on these results, the electromagnetic field effect was mainly responsible for the signal enhancements in SERS measurements. Also, the obtained signals were exponentially decayed due to the distances of the surface of AgNPs. Based on the SERS intensities of the conjugated molecules, the contribution of CT effect to SERS for these examined molecules were limited.     

Characterization and photocatalytic activity of Fe- and N-co-deposited TiO2 and first-principles study for electronic structure

Titanium dioxide (TiO₂), co-deposited with Fe and N, is first implanted with Fe by a metal plasma ion implantation (MPII) process and then annealed in N₂ atmosphere at a temperature regime of 400-600 °C. First-principle calculations show that the (Fe, N) co-deposited TiO₂ films produced additional band gap levels at the bottom of the conduction band (CB) and on the top of the valence band (VB). The (Fe, N) co-deposited TiO₂ films were effective in both prohibiting electron-hole recombination and generating additional Fe-O and N-Ti-O impurity levels for the TiO₂ band gap. The (Fe, N) co-deposited TiO₂ has a narrower band gap of 1.97 eV than Fe-implanted TiO₂ (3.14 eV) and N-doped TiO₂ (2.16 eV). A significant reduction of TiO₂ band gap energy from 3.22 to 1.97 eV was achieved, which resulted in the extension of photocatalytic activity of TiO₂ from UV to Vis regime. The photocatalytic activity and removal rate were approximately two-fold higher than that of the Fe-implanted TiO₂ under visible light irradiation.     

ToF-SIMS imaging of the nanoscale phase separation in polymeric light emitting diodes: effect of nanostructure on device efficiency

The nanostructure of the light emissive layer (EL) of polymer light emitting diodes (PLEDs) was investigated using force modulation microscopy (FMM) and scanning time-of-flight secondary ion mass spectrometry (ToF-SIMS) excited with focused Bi(3)(2+) primary beam. Three-dimensional nanostructures were reconstructed from high resolution ToF-SIMS images acquired with different C(60)(+) sputtering times. The observed nanostructure is related to the efficiency of the PLED. In poly(9-vinyl-carbazole) (PVK) based EL, a high processing temperature (60 °C) yielded less nanoscale phase separation than a low processing temperature (30 °C). This nanostructure can be further suppressed by replacing the host polymer with poly[oxy(3-(9H-9-carbazol-9-ilmethyl-2-methyltrimethylene)] (SL74) and poly[3-(carbazol-9-ylmethyl)-3-methyloxetane] (RS12), which have similar chemical structures and energy levels as PVK. The device efficiency increases when the phase separation inside the EL is suppressed. While the spontaneous formation of a bicontinuous nanostructure inside the active layer is known to provide a path for charge carrier transportation and to be the key to highly efficient polymeric solar cells, these nanostructures are less efficient for trapping the carrier inside the EL and thus lower the power conversion efficiency of the PLED devices.     

Determination of fat-soluble vitamins and carotenoids in standard reference material 3280 multivitamin/multielement tablets by liquid chromatography with absorbance detection

The concentrations of selected fat-soluble vitamins and carotenoids in Standard Reference Material (SRM) 3280 Multivitamin/Multielement Tablets have been determined by two independent LC methods, with measurements performed by the National Institute of Standards and Technology (NIST). This SRM has been prepared as part of a collaborative effort between NIST and the National Institutes of Health Office of Dietary Supplements. The SRM is also intended to support the Dietary Supplement Ingredient Database that is being established by the U.S. Department of Agriculture. The methods used at NIST to determine the concentration levels of vitamins A and E, and beta-carotene in the SRM used RPLC with absorbance detection. The relative precision of these methods ranged from 2 to 8% for the analytes measured. SRM 3280 is primarily intended for use in validating analytical methods for the determination of selected vitamins, carotenoids, and elements in multivitamin/multielement tablets and similar matrixes.     

Mechanochromic luminescent property of a polypeptide-based dendron

We report herein the mechanochromic luminescent property of a dendritic polypeptide with a fluorescent aromatic moiety at the focal point. The different luminescent property of 1 under mechanical stimulus is attributed to the switch of self-assembled structures. Moreover, the photoluminescence property of 1 also depends on the thermal history.     

Colorimetric detection of cyanide with phenyl thiourea derivatives

Three structurally simple thiourea derivatives 1-3 were prepared, and their chromogenic behaviors toward various anions were investigated in aqueous solution. Among them 1 showed good sensitivity and selectivity for cyanide ion and also can distinguish it from other anions by different color changes. Besides that, the receptor 1 has a sensitive detection limit (1.27 μM) for cyanide ion accordingly it can be used as a colorimetric sensor for the determination of cyanide ion. The use of the test strip of sensor 1 to detect cyanide ion was also reported.     

A rapid and economical method for profiling feature heights during microfabrication

Quality control is an important and integral part to any microfabrication process. While the widths of features often can be easily assessed by light microscopy, the heights of the fabricated structures are more difficult to determine. Here, we present a rapid, accurate, and low-cost method to measure the heights of microfabricated structures during and after the fabrication process. This technique is based on white-light interferometry, which offers accuracy on the submicrometre scale.