Behaviour of rhodamine B in aqueous LiCl solution

Absorption, pH and electric conductance of rhodamine BLiClH₂O solutions are examined. The obtained results show that aqueous rhodamine B has a tendency to dimerize by the addition of LiCl. Other features on the structural properties of rhodamine B in aqueous LiCl solutions are discussed briefly.     

Trimethylsilylmethyl derivatives of thallium(III)

Some trimethylsilylmethyl derivatives of thallium(III) have higher stability and unusual coordination behavior in comparison with simple alkylthallim(III) analogs for steric reasons.     

Relative stability of η-cyclopentadienyl(olefin)ruthenium cations: The first estimation of the nature of the Ru-olefin bond

Relative stability in coordination of substituted styrene derivatives to [Ru(η-C₅H₅)(dtpe)]⁺ (dtpe = 1,2-bis(di-p-tolylphosphino)-ethane) was determined by NMR spectroscopy to reveal unusually weak substituent dependency of the stability.     

A facile synthesis of [3ncyclophanes,in which aromatic rings are connected with -CH2CO-CH2- bridges

The title compounds, I, were synthesized by the dialkylation of TosMIC, II, with appropriate bis (halomethyl) compounds, III, under phase-transfer condition, followed by acid hydrolysis.     

Circumventing air bubbles in microfluidic systems and quantitative continuous-flow PCR applications

Polymerase chain reaction (PCR) is an essential part of research based on genomics or cell analysis. The development of a microfluidic device that would be suitable for high-temperature-based reactions therefore becomes an important contribution towards the integration of micro-total analysis systems (μTAS). However, problems associated with the generation of air bubbles in the microchannels before the introduction of the assay liquid, which we call the “initial start-up” in this study, made the flow irregular and unstable. In this report, we have tried to address these problems by adapting a novel liquid-flow method for high-temperature-based reactions. A PDMS-based microfluidic device was fabricated by soft-lithography techniques and placed on a cartridge heater. The generation of the air bubbles was prevented by introducing the fluorinated oil, an inert and highly viscous liquid, as the cap just before the introduction of the sample solutions into the microchannels. The technique was applied for continuous-flow PCR, which could perform PCR on-chip in a microfluidic system. For the evaluation of practical accuracy, plasmid DNA that serves as a reference molecule for the quantification of genetically modified (GM) maize was used as the template DNA for continuous-flow PCR. After PCR, the products were collected in a vial and analyzed by gel electrophoresis to confirm the accuracy of the results. Additionally, quantitative continuous-flow PCR was performed using TaqMan technology on our PCR device. A laser detection system was also used for the quantitative PCR method. We observed a linear relationship between the threshold cycle (Ct) and the initial DNA concentration. These results showed that it would be possible to quantify the initial copies of the template DNA on our microfluidic device. Accurate quantitative DNA analysis in microfluidic systems is required for the integration of PCR with μTAS, thus we anticipate that our device would have promising potential for applications in a wide range of research.     

Chiral charge-density waves

We discovered the chirality of charge-density waves (CDW) in 1T-TiSe? by using STM and time-domain optical polarimetry. We found that the CDW intensity becomes Ia?∶Ia?∶Ia? = 1∶0.7 ± 0.1∶0.5 ± 0.1, where Ia(i) (i=1,2,3) is the amplitude of the tunneling current contributed by the CDWs. There were two states, in which the three intensity peaks of the CDW decrease clockwise and anticlockwise. The chirality in CDW results in the threefold symmetry breaking. Macroscopically, twofold symmetry was indeed observed in optical measurement. We propose the new generalized CDW chirality H(CDW) ≡ q?·(q?×q?), where q(i) are the CDW q vectors, which is independent of the symmetry of components. The nonzero H(CDW)-the triple-q vectors do not exist in an identical plane in the reciprocal space-should induce a real-space chirality in CDW system.     

Fabrication and hard X-ray photoemission analysis of photocathodes with sharp solar-blind sensitivity using AlGaN films grown on Si substrates

Photocathode devices operating in reflection-mode, where the photoemission is detected on the same side as the light irradiation, were developed for the detection of deep ultraviolet light by using p-Al_xGa_1−xN films grown on Si(1 1 1) substrates. The external quantum efficiencies were as high as 20-15% at 200 nm and 280 nm, while the value was as low as 10⁻²% at 310 nm. The on-off ratio was more than four orders of magnitude, which represents high solar-blind sensitivity. The escape probability of Al_xGa_1−xN photocathode was decreased with increase of AlN mole fraction. The effective barrier potential against the photoelectron emission near the surface was reduced due to the upward shift of conduction band of Al_xGa_1−xN. The photoemission from the Al_xGa_1−xN films terminated with Cs-O adatoms will be discussed in terms of band diagrams that were evaluated by hard X-ray photoelectron spectroscopy.