Direct observation of chiral susceptibility in the canonical spin glass AuFe

The extraordinary Hall resistivity rho(xy) and the magnetization M of a canonical spin glass AuFe (8 at.% Fe) were measured simultaneously as functions of temperature with the best care to the thermal and the magnetic field hysteresis. The data of rho(xy) show an anomaly at the spin glass transition temperature T(g) and have different zero field cooling (ZFC) and field cooling (FC) measurements below T(g). Moreover, the value of rho(xy)/M, which represents the chiral susceptibility of the system in the present case, also shows the difference between ZFC and FC measurements. The results are consistent with the predictions of the chirality scenario of canonical spin glasses by Kawamura.     

Nanotechnology R&;D Policy of Japan and Nanotechnology Support Project

In the 2nd Science and Technology Basic Plan (2001–2005), the area of nanotechnology and materials is designated one of the four prioritized areas in funding. Following this plan, Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Ministry of Economy, Trade and Industries (METI), the main funding ministries, and their organizations, Japan Society for the Promotion of Science (JSPS), Japan Science and Technology Agency (JST), National Institute for Materials Science (NIMS), RIKEN, New Energy and Industrial Technology Organization (NEDO), and National Institute of Advanced Industrial Science and Technology (AIST) promotes their research programs. Besides, in order to promote interdisciplinary, interorganizational, and international collaboration of researchers, Nanotechnology Support Project (NSP) was started by MEXT in 2002. The project has two missions: informational support and common use facility support. Nanotechnology Researchers Network Center of Japan is responsible for informational support, and 14 universities and national research institutes are responsible for common use facility support.     

Aqueous chromatographic system for the quantification of propofol in biological fluids using a temperature-responsive polymer modified stationary phase

A new method for the quantitative analysis of monkey serum propofol, which is widely used as an anaesthetic agent, was developed by utilizing a temperature-responsive polymer of N-isopropylacrylamide (NIPAAm) and butyl methacrylate (BMA) as the stationary phase of HPLC–fluorescence detection. This poly(NIPAAm-co-BMA) copolymer undergoes a reversible phase transition from a hydrophilic to a hydrophobic microstructure when triggered by change in the temperature. Also this chromatographic system is possible to separate the analytes by using only water as a mobile phase. A pretreatment of the serum (80 μL) was only solid-phase extraction, and the recovery rate of propofol and internal standard was more than 77%, respectively. This method covered the calibration range from 0.5 μg/mL to 10 μg/mL and allowed a reproducible quantification of the serum propofol in administrated monkey serum. The intra- and inter-assay relative standard deviations were less than 14.1%. In addition, there was good relationship of the quantification values between the developed method and the widely used reversed-phase HPLC method. Our developed method has proven to be useful for a simple analysis of propofol in clinical practice, because the avoidance of complicated mobile phase preparation was possible, and only temperature changing could regulate the retention time of the analyte. In addition, by using water instead of fossil fuel, it is the ideal analytical method according to green chemistry.     

Investigation of individual micrometer-size Kosa particle with on-site combination of electron microscope and synchrotron X-ray microscope.

The Kosa (yellow sand) aerosol affects the global environment as well as human health because it migrates from the interior of China to other areas, absorbing various atmospheric elements. Investigation into individual Kosa aerosol particles, which are submicroscopic to several tens of micrometers in diameter, is required to resolving the issue. We installed a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDX) on a synchrotron radiation (SR) beam line and introduced the SR beam into the SEM chamber for combinatorial application of SEM-EDX and SR X-ray fluorescence (SR-XRF) spectrometry to individual particles. It should be noted that detailed topographic observation by SEM and sensitive elemental analysis by SR-XRF, both crucial for individual particle measurement but which previously had to be carried out separately, were jointly performed inside the SEM chamber in this setup. Here, we show that SR-XRF results, in conjunction with SEM images, contributed toward resolving individual particle dispositions. Atmospheric sulfur primarily adheres to calcium in the aerosol particles and the particle surface roughens as a consequence of the chemical reaction between the two elements.     

Unexpectedly stable artificial duplex from flexible acyclic threoninol

A new foldamer, acyclic threoninol nucleic acid (aTNA), has been synthesized by tethering each of the genetic nucleobases A, G, C, and T to d-threoninol molecules, which were then incorporated as building blocks into a scaffold bearing phosphodiester linkages. We found that with its fully complementary strand in an antiparallel fashion, the aTNA oligomer forms an exceptionally stable duplex that is far more stable than corresponding DNA or RNA duplexes, even though single-stranded aTNA is rather flexible and thus does not take a preorganized structure.     

Characterization of Ultra‐Thin Temperature‐Responsive Polymer Layer and Its Polymer Thickness Dependency on Cell Attachment/Detachment Properties

Ultra thin poly(N‐isopropylacrylamide) (PIPAAm) modified glass coverslips (PIAPAm‐CS) using electron beam irradiation exhibited a clear relationship between the polymer thickness and thermal cell adhesion/detachment behavior. The polymer thickness dependency and the characteristic of ultra thin PIPAAm layer, has been illustrated in terms of the molecular motion of the modified PIPAAm chains. PIPAAm‐CSs surfaces with various area‐polymer densities and thicknesses were characterized by AFM and protein adsorption assay. The newly obtained results gave a further insight into the illustration. Finally, the future application of intelligent surfaces was discussed for fabricating tissue and organ.

     

Pneumatic handling of droplets on-demand on a microfluidic device for seamless processing of reaction and electrophoretic separation

Sequential operations of pre-separation reaction process by picoliter droplets and following electrophoretic separation process were realized in a single microfluidic device with pneumatic handling of liquid. The developed device consists of a fluidic chip made of PDMS, an electrode substrate, and a temperature control substrate on which thin film heater/sensor structures are fabricated. Liquid handling, including introduction of liquid samples, droplet generation, and merging of droplets, was implemented by pneumatic manipulation through microcapillary vent structures, allowing air to pass and stop liquid flow. Since the pneumatic manipulations are conducted in a fully automated manner by using a programmable air pressure control system, the user simply has to load liquid samples on each liquid port of the device. Droplets of 420 pL were generated with an accuracy of ± 2 pL by applying droplet generation pressure in the range of 40-100 kPa. As a demonstration, a binding reaction of a 15 mer ssDNA with a peptide nucleic acid oligomer used as an oligoprobe followed by denaturing electrophoresis to discriminate a single-base substitution was performed within 1.5 min. By exploiting the droplet-on-demand capability of the device, the influence of various factors, such as reaction time, mixing ratio and droplet configurations on the ssDNA-peptide nucleic acid binding reaction in the droplet-based process, was studied toward realization of a rapid detection method to discriminate rapid single-base substitution.     

Evolution of the Kondo effect in a quantum dot probed by shot noise

We measure the current and shot noise in a quantum dot in the Kondo regime to address the nonequilibrium properties of the Kondo effect. By systematically tuning the temperature and gate voltages to define the level positions in the quantum dot, we observe an enhancement of the shot noise as temperature decreases below the Kondo temperature, which indicates that the two-particle scattering process grows as the Kondo state evolves. Below the Kondo temperature, the Fano factor defined at finite temperature is found to exceed the expected value of unity from the noninteracting model, reaching 1.8±0.2.