Growth of sputter-deposited gold nanoparticles in ionic liquids

The growth of gold nanoparticles (NPs) synthesized by sputter deposition on an ionic liquid surface is studied in situ in the bulk phase of the ionic liquids (ILs) 1-butyl-3-methylimidazolium dicyanamide [C(1)C(4)Im][N(CN)(2)], 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide [C(1)C(4)Im][Tf(2)N], 1-butyl-3-methylimidazolium tetrafluoroborate [C(1)C(4)Im][BF(4)], 1-butyl-3-methylimidazolium hexafluorophosphate [C(1)C(4)Im][PF(6)] and 1-butyl-3-methylimidazolium triflate [C(1)C(4)Im][TfO]. It is found that primary nanoparticles with a diameter smaller than 2.5 nm are present in the sample immediately after sputtering. Growth of these primary particles proceeds after the end of the sputtering process and stops when the nanoparticles reach a certain size. Depending on the viscosity of the ionic liquid this growth process can proceed several hours to several days. The growth speed is fastest for the least viscous ionic liquid and follows the trend [C(1)C(4)Im][N(CN)(2)] > [C(1)C(4)Im][Tf(2)N] > [C(1)C(4)Im][TfO] > [C(1)C(4)Im][BF(4)] > [C(1)C(4)Im][PF(6)]. It is also found that a higher concentration of sputtered gold results in faster growth of the gold nanoparticles. A discussion on the growth mechanism of sputtered gold NPs is included.     

Synthetic studies on perophoramidine and the communesins: construction of the vicinal quaternary stereocenters

An efficient synthetic strategy for installation of the two vicinal quaternary carbon centers of the communesins is reported. Key steps include the O-allylation/Claisen rearrangement of spirolactone systems, which are formed by tandem intramolecular Heck cyclization/carbonylation. Substituent and solvent effects on the stereochemical outcome of the Claisen rearrangements have been examined. The stereochemical assignment of the allyl spirolactone previously reported as 17 has now been revised to 31, which has the communesin relative configuration at the quaternary carbons. Key C-allyl spirolactone 59 bearing functional handles required for the communesin core has been constructed with a 9.8:1 diastereomer ratio.     

Altered protein profiles in human umbilical cords with preterm and full‐term delivery

Several biomarkers are routinely used clinically for predicting preterm labor; however, these factors are either nonspecific or detected too late. Here, we performed protein profiles in preterm‐ and term‐derived human umbilical cord by using 2DE. Approximately 200 different proteins were identified between preterm‐ and term‐delivered umbilical cords. Among them, 48 proteins were identified. A comparison of preterm proteome to that of term proteome revealed potential candidates for biomarkers, such as hypoxia‐inducible proteins, phosphorylated heat‐shock protein 27 (HSP27), transgelin, vimentin, and transferrin that are specific to preterm umbilical cords. Especially, HSP27 in preterm‐derived umbilical cords shows a significant increase in the mono‐ and tetra‐phosphorylation. The real importance of all of HSP27 phosphorylation as well as hypoxia‐inducible factor 1alpha, and glyceraldehyde 3‐phosphate dehydrogenase require further validation in vitro and in vivo; nevertheless, we believe that they could represent promising diagnostic targets for detection of sudden early delivery. In conclusion, the results of the current study may provide important insights into the molecular mechanisms underlying umbilical cord development.     

Residual d.c. measurement in in-plane switching liquid crystal displays by a new light minimum/maximum method on a polyimide layer

The measurement of residual d.c. in in-plane switching liquid crystal displays on a rubbed polyimide surface was investigated. We propose a new residual d.c. measurement method, named the ‘light minimum/maximum method’. The precision of residual d.c. measurement by the light minimum/maximum method was found to be greater than that of the conventional flicker minimizing method.     

Fast switching and luminance-controlled fringe-field switching liquid crystal device for vehicle display

ABSTRACT

Liquid crystal displays (LCDs) for vehicle displays should exhibit a fast response time in wide temperature range and wide-viewing angle in horizontal and downward directions without grey-scale inversion but limited brightness in the upward direction because the display images can be reproduced in the front window glass of a vehicle, affecting driver’s front visibility. Currently, fringe-field switching (FFS) liquid crystal device is widely commercialised for high resolution and wide-viewing-angle LCD; however, it needs to improve response times and limit the display brightness in the upward direction. As a solution, we propose a homogeneously aligned liquid crystal device in which liquid crystal director does tilt as well as twist deformation in a confined area by both vertical- and fringe-electric fields, exhibiting about two times faster decay response time than that of conventional FFS mode with suppressed luminance in the upward direction. The proposed liquid crystal device can be applied to LCDs for vehicle displays.