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.     

Quinolone Analogues 12: Synthesis and Tautomers of 2‐Substituted 4‐Quinolones and Related Compounds

The 4‐quinolone‐2‐carboxylates 4a,b were converted into the 4‐quinolone‐2‐carbohydrazides 5a,b , hydrazones 6,7,10 , and related compounds 8,9,11 . The 4‐methoxyquinoline‐2‐carboxylate 12 was also transformed into the 4‐methoxyquinoline‐2‐carbohydrazide 13 , which was modified to the hydrazone 14 and related compound 15 . The antimicrobial activities of compounds 6b and 14 are described together with the 4‐oxo and 4‐hydroxy tautomers of compounds 4‐11 in deuteriodimethyl sulfoxide and deuteriotrifluoroacetic acid.     

Nitroxide-mediated photo-controlled/living radical polymerization of ethyl acrylate

The nitroxide-mediated photo-controlled/living radical polymerization of ethyl acrylate was attained using (2RS,2′RS)-azobis(4-methoxy-2,4-dimethylvaleronitrile) as the initiator, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl as the mediator, and (4-tert-butylphenyl)diphenylsulfonium triflate as the photo-acid generator. The photopolymerization was performed in acetonitrile at room temperature by irradiation with a high-pressure mercury lamp. The molecular weight distribution of the resulting polymer decreased as the monomer concentration decreased. It was confirmed that the polymerization was controlled on the basis of the linear correlations for the first-order time-conversion plots and the plots of the molecular weight vs. the reciprocal of the initial concentration of the initiator, although the conversion–molecular weight plots did not show a completely linear correlation. The block copolymerization with methyl methacrylate accompanied by no deactivation of the growing polymer chain end supported the livingness of the polymerization.     

Schmitt-Vogel type lemma for reductions

The lemma given by Schmitt and Vogel is an important tool in the study of the arithmetical rank of squarefree monomial ideals. In this paper, we give a Schmitt-Vogel type lemma for reductions as an analogous result.