Production of Noble-Metal Nanohelices Based on Nonlinear Dynamics in Electrodeposition of Binary Copper Alloys.

Spatiotemporal pattern formation is dynamic self-organization widely observed in nature and drives various functions. Among these functions, chirality plays a central role. The relationship between dynamic self-organization and chirality has been an open question; therefore, the production of chiral nanomaterials by dynamic self-organization has not been achieved. Here, we show that the confinement of a two-dimensional spatiotemporal micropattern via the electrodeposition of a binary Cu alloy into a nanopore induces mirror symmetry breaking to produce a helical nanostructure of the noble-metal component although it is still not yet possible to control the handedness at this stage. This result suggests that spatiotemporal symmetry breaking functions as a mirror symmetry breaking if cylindrical pores are given as the boundary condition. This study can be a model system of how spatiotemporal symmetry breaking plays a role in mirror symmetry breaking, and it proposes a new approach to producing helical nanomaterials through dynamic self-organization.

Spontaneous Symmetry Breaking of Nanoscale Spatiotemporal Pattern as the Origin of Helical Nanopore Etching in Silicon.

Nanometric chiral objects such as twisted or helical nanoribbons represent a new class of objects having important potential in a large panel of applications, taking advantage, for example, of electromechanical or optical chirality, local chiral environment for catalysis, and chiral recognition. Supramolecular chemistry has played a central role in the production of such structures through either chiral macromolecules/foldamers or the self-assembly of chiral molecules; the latter can also be used as templates for the sol-gel transcription to silica materials, offering them polymorphisms with further structural stability. Here, we report a totally different and dynamic approach to produce helical mesostructures. This study focuses on helical nanopores that are spontaneously formed in the platinum-assisted chemical etching of silicon by dynamic self-organization under a nonequilibrium state. The symmetry breaking of a helical nanopore formation is achieved by the spatial symmetry breaking of a spatiotemporal pattern at the nanoscale and without incorporation of chiral molecules. Rotational motion of the platinum nanocatalyst, which is regarded as a spatiotemporal pattern at the etching frontier (the platinum/silicon interface), induces precession movement of the nanocatalyst, and movement of the catalyst during etching forms helical nanopores in the silicon. We consider that this study is an important milestone to understand the close relation between spatiotemporal pattern formation and the dynamic emergence of symmetry breaking in chemical reactions.

Simultaneous Determination of Cr, As, Se, and Other Trace Metal Elements in Seawater by ICP-MS with Hybrid Simultaneous Preconcentration Combining Iron Hydroxide Coprecipitation and Solid Phase Extraction Using Chelating Resin.

In the present study, ICP-MS with a new hybrid simultaneous preconcentration combining solid phase extraction using chelating resin and iron hydroxide coprecipitation in one batch at a single pH adjustment (pH 6.0) were developed for multielement determination of trace metal ions in seawater. In multielement determination, the present method makes it possible to determine Cr(III), As(V), Se (IV), and other 14 trace metal elements (Ti, V, Co, Ni, Cu, Zn, Zr, Ge, Cd, Sb, Sn, W, Pb, and U) in seawater. Moreover, for speciation analyses of Cr, As, and Se, the pH dependence on recovery for the different chemical forms of Cr, As, and Se was investigated. In speciation analyses, Cr, As, and Se were determined as the total of Cr (III) and a part of Cr (VI), total of As (III) and As (V), and Se(IV), respectively. Determination of total of Se and Cr(VI) remains as future task to improve. Nevertheless, the present method would have possibility to develop as the analytical method to determine comprehensively most metal elements in all standard and guideline values in quality standard in environmental water in Japan, that is, most toxic metal elements in environmental water.

Novel 7α-alkoxy-17α-(4'-halophenylethynyl)estradiols as potential SPECT/PET imaging agents for estrogen receptor expressing tumours: synthesis and binding affinity evaluation.

In order to develop potential radiolabelled probes for imaging estrogen receptor (ER) positive tumours, we have synthesized and characterized a series of novel 7α-alkoxy-17α-(4'-iodophenylethynyl)estra-1,3,5(10)-triene-3,17ß-diols and 7α-alkoxy-17α-(4'-fluorophenylethynyl)estra-1,3,5(10)-triene-3,17ß-diols. The fluoro-substituted compounds showed a higher ER binding affinity than the corresponding iodo-derivatives, where 7α-methoxy- and 17α-(4'-fluorophenylethynyl)estra-1,3,5(10)-triene-3,17ß-diol showed the highest ER binding affinities (RBA=80.9% and 78.9%, respectively), among the halophenylethynyl compounds studied and should be further explored as potential PET biomarkers for imaging of ER expressing tumours.

Radioiodinated ligands for the estrogen receptor: effect of different 7-cyanoalkyl chains on the binding affinity of novel iodovinyl-6-dehydroestradiols.

Three novel 17 alpha-ethynyl-Delta(6,7)-estra-3,17beta-diols and their 17 alpha-[(125)I]-iodovinyl derivatives, containing different C7-cyanoalkyl chains, were studied as potential radioligands for the estrogen receptor. The influence of the chain length on the biological behaviour of the compounds was assessed through in vitro ER binding assays of the ethynyl derivatives and breast cancer cell uptake studies of the 17 alpha-[(125)I]-iodovinyl-Delta(6,7)-estra-3,17beta-diols. A difference in alkyl chain induced a decrease in ER binding affinities of substances, however, the receptor-binding affinities (RBA) of all compounds were lower than that of estradiol itself. In addition, a non-specific cell binding was observed which is in accordance with the encountered ethynyl RBA values suggesting that the uptake is not ER mediated.

Effects of monochromatic light on time sense for short intervals.

We examined the effects of monochromatic light on the time sense and the central nervous system. Nine young adult volunteers participated in this study. They were exposed to red-light and blue-light environments (illuminance was kept at 310 lx). We evaluated the time sense by time-production tests of 90 s and 180 s and measured the P300 event-related potentials during an auditory oddball task. The 90-s time intervals produced by subjects in the two monochromatic light conditions were not significantly different. However, the 180-s time interval produced in the red-light condition (163.2+/-50.4 s) was significantly (p<0.05) shorter than that in the blue-light condition (199.0+/-54.4 s). The peak latency of P300 in the red light (322.2+/-26.6 ms) was found to be significantly (p<0.05) shorter also than that in the blue light (332.6+/-20.2 ms). The feelings measured by the visual analogue scales in the two light conditions were not significantly different. These results indicate that the time sense ran faster in the red-light than in the blue-light condition. We suggest that the higher activity in the central nervous system that is accounted for by the shorter latency of P300 is related to the acceleration of the time sense.