Electrochemical Determination of D‐Glucose Using Nortropine‐N‐oxyl under Physiological Conditions

Nortropine‐N‐oxyl (NNO) was synthesized in a single step from nortropine. The electrocatalytical activity of NNO was evaluated by cyclic voltammetry in pH7.0 phosphate buffer solution. The anodic peak current for ethanol, isopropanol and glucose was enhanced, showing these alcohols were oxidized by electrocatalytic effect of NNO. On the other hand, TEMPO derivative (4‐hydroxy‐2,2,6,6,‐terramethylpiperidine N‐oxyl free radical) could not oxidize the alcohols under the same condition. The electrochemical response of the NNO to glucose was investigated. The anodic peak current increased with an increase in the concentration of glucose. A linear response to the glucose concentration ranging from 0.1 to 10 mM was obtained.     

Fission of giant vesicles accompanied by hydrophobic chain growth through polymerization-induced self-assembly

In order to clarify the formation mechanisms of micrometer-sized spherical vesicles through the polymerization-induced self-assembly of amphiphilic poly(methacrylic acid)-block-poly(methyl methacrylate-random-methacrylic acid), PMAA-b-P(MMA-r-MAA), the nitroxide-mediated photocontrolled/living radical polymerization initiated by a PMAA end-capped with 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl was performed in an aqueous methanol solution. The polymerization proceeded in a living manner during the self-assembly. The vesicles produced during the early stage of the polymerization were not completely spherical and had dents and very small holes on their surface. As the hydrophobic P(MMA-r-MAA) block chains grew by the polymerization, the contorted vesicles were changed into half-sized elliptical vesicles accompanied by enlargement of the dents and holes. The vesicles were finally transformed into much smaller spherical vesicles by further growth of the hydrophobic chains. The mechanisms of the vesicles by fission involved the outside separation by the expansion of the dents and holes on the surface and the inside separation by budding.     

Biological Dosimetry by the Triage Dicentric Chromosome Assay - Further validation of International Networking

Biological dosimetry is an essential tool for estimating radiation doses received to personnel when physical dosimetry is not available or inadequate. The current preferred biodosimetry method is based on the measurement of radiation-specific dicentric chromosomes in exposed individuals' peripheral blood lymphocytes. However, this method is labour-, time- and expertise-demanding. Consequently, for mass casualty applications, strategies have been developed to increase its throughput. One such strategy is to develop validated cytogenetic biodosimetry laboratory networks, both national and international. In a previous study, the dicentric chromosome assay (DCA) was validated in our cytogenetic biodosimetry network involving five geographically dispersed laboratories. A complementary strategy to further enhance the throughput of the DCA among inter-laboratory networks is to use a triage DCA where dose assessments are made by truncating the labour-demanding and time-consuming metaphase-spread analysis to 20 to 50 metaphase spreads instead of routine 500 to 1000 metaphase spread analysis. Our laboratory network also validated this triage DCA, however, these dose estimates were made using calibration curves generated in each laboratory from the blood samples irradiated in a single laboratory. In an emergency situation, dose estimates made using pre-existing calibration curves which may vary according to radiation type and dose rate and therefore influence the assessed dose. Here, we analyze the effect of using a pre-existing calibration curve on assessed dose among our network laboratories. The dose estimates were made by analyzing 1000 metaphase spreads as well as triage quality scoring and compared to actual physical doses applied to the samples for validation. The dose estimates in the laboratory partners were in good agreement with the applied physical doses and determined to be adequate for guidance in the treatment of acute radiation syndrome.     

Asymmetric Synthesis of Indoline from Achiral Phthalimide Involving Crystallization-Induced Deracemization

Asymmetric synthesis was performed by combining the photochemical reaction of an achiral substrate followed by crystallization-induced deracemization. The results indicated that a fused indoline produced by photochemical intramolecular δ-hydrogen abstraction and cyclization of N-(5-chloro-2-methylphenyl)phthalimide crystallized as a racemic conglomerate. Since this substrate has an aminal skeleton, racemization involving a ring-opening and ring-closing equilibrium process occurred under suitable conditions. Efficient racemization was observed in acetone containing a catalytic base, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Crystallization-induced dynamic deracemization by Viedma ripening from racemic indoline was performed with an excellent enantioselectivity of 99 % ee. Furthermore, one-pot asymmetric synthesis of the indoline was achieved by the photochemical reaction of achiral phthalimide followed by continuous attrition-enhanced deracemization converging to 99 % ee of enantiomeric crystals. This is the first example of asymmetric expression and amplification by photochemical hydrogen abstraction and crystallization-induced dynamic deracemization.     

Development of system and technology for m?ssbauer spectroscopic microscope

We have been developing a “M?ssbauer Spectroscopic Microscope (MSM)” which consists of a focusing lens for 14.4?keV γ-rays and a high precision X–Y stage. The measuring system both for electrons and γ-rays combined with a new M?ssbauer driver, i.e., “a moving coil actuator with a liner encoder” enables us to measure the mapping images simultaneously corresponding to different spectral components. The system has a controlling system based on a LabVIEW program and a LIST mode data acquisition system (NIKI-GLASS/A3100). To investigate a correlation between the microstructure of a sample and ⁵⁷Fe atoms, a scanning electron microscope (APCO/Mini-EOC) is also installed to this system.