On permutations of wires and states

We characterize a permutation as a sequence of wire-cycle periods and a sequence of state-cycle periods. These sequences are called a wire-sequence and a state-sequence, respectively. A relation between wire-cycles and state-cycles is discussed and some combinatorial problems on cycle periods of permutations are solved. An efficient method for constructing the state-sequence corresponding to a given wire-sequence is also described.     

Behavior of Deuterium in Boron Films Covered by Oxygen-Containing Layer

Boron is an attractive candidate of the first wall coating materials in fusion reactors. The behavior of deuterium implanted into boron films has been studied . This paper reports the effect of thin oxygen-containing boron layer on the behavior of deuterium im- planted into boron film by X-ray photoelectron spectroscopy （XPS） and thermal desorption spectroscopy （TDS）.     

Chemical states of tritium in solid lithium compounds irradiated with neutrons

Chemical states of tritium existing in neutron-irradiated solid lithium compounds were analyzed using a radiometric method. Nearly 100% of tritium was found in the T⁺ state in LiOH, Li₂O₂ and Li₃N, while the T^– state predominated in LiH, Li₇Pb₂ and Li₂C₂. Tritium incorporated in Li₂O, Li₂S, LiF, LiCl, LiBr and LiI was distributed over the T⁺, T^– and T⁰ states. In Li₂O crystals, the distribution of tritium in the T⁺ state increased from 58% to 81% with increasing neutron fluence from 2.5×10¹⁶ cm^–2 to 6.3×10¹⁷ cm^–2.     

Asymmetric Kumada-Corriu cross-coupling reaction with Pd2(dba)3 and an N-Ar axially chiral mimetic-type ligand catalyst

A catalyst comprised of Pd₂(dba)₃·CHCl₃ and an N-Ar axially chiral mimetic-type ligand, (S)-N-[2-(diphenylphosphanyl)naphthalene-1-yl]-2-(piperidinylmethyl)piperidine, provides good enantioselectivities for the asymmetric Kumada-Corriu cross-coupling reaction of 1-phenylethylmagnesium chloride and E-β-bromostyrene derivatives with which it is more difficult to achieve high enantioselectivity. Furthermore, in the case of styrene derivatives bearing both vinyl and aryl bromide groups, the chemoselective asymmetric cross-coupling reaction of the vinyl bromide group is observed. This N-Ar axially chiral mimetic-type ligand allows easy synthesis of a wide variety of analogues, and starting from the initial ligand, the enantioselectivity of coupling products is improved by modifying the structure in the ligand.     

Simultaneous determination of nitrite, nitrate, thiocyanate and uric acid in human saliva by capillary zone electrophoresis and its application to the study of daily variations

Simultaneous determination of nitrite (NO2-), nitrate (NO3-), thiocyanate (SCN-) and uric acid in human saliva was performed by capillary zone electrophoresis using a coated capillary with reversed electroosmotic flow (EOF), using a 100 mM sodium phosphate buffer at pH 6.5 as a running buffer. Saliva samples were deproteinized with acetonitrile and filtered through a membrane filter. The important advantages of the reported method are: simple operation, short analysis time, minimal sample pre-treatment and sample dilution. In order to evaluate the daily variations of the anionic components, the concentrations were determined in the human saliva of four healthy volunteers upon waking and at 2qh intervals during a day.     

Computational assignment of the EC numbers for genomic-scale analysis of enzymatic reactions

The EC (Enzyme Commission) numbers represent a hierarchical classification of enzymatic reactions, but they are also commonly utilized as identifiers of enzymes or enzyme genes in the analysis of complete genomes. This duality of the EC numbers makes it possible to link the genomic repertoire of enzyme genes to the chemical repertoire of metabolic pathways, the process called metabolic reconstruction. Unfortunately, there are numerous reactions known to be present in various pathways, but they will never get EC numbers because the EC number assignment requires published articles on full characterization of enzymes. Here we report a computerized method to automatically assign the EC numbers up to the sub-subclasses, i.e., without the fourth serial number for substrate specificity, given pairs of substrates and products. The method is based on a new classification scheme of enzymatic reactions, named the RC (reaction classification) number. Each reaction in the current dataset of the EC numbers is first decomposed into reactant pairs. Each pair is then structurally aligned to identify the reaction center, the matched region, and the difference region. The RC number represents the conversion patterns of atom types in these three regions. We examined the correspondence between computationally assigned RC numbers and manually assigned EC numbers by the jackknife cross-validation test and found that the EC sub-subclasses could be assigned with the accuracy of about 90%. Furthermore, we examined the correlation with genomic information as represented by the KEGG ortholog clusters (OC) and confirmed that the RC numbers are correlated not only with elementary reaction mechanisms but also with protein families.     

Syntheses of pyrido[1,2-a][1,3,5]triazin-4-one C-deoxyribonucleosides

We achieved the syntheses of new C-deoxyribonucleosides bearing pyrido[1,2-a][1,3,5]triazin-4-one derivatives using palladium-catalyzed Heck-type coupling. Some of these C-deoxyribonucleosides were able to convert to phosphoramidite reagents, which can be used for DNA synthesizer. DNA oligomers including pyrido[1,2-a][1,3,5]triazin-4-one C-deoxyribonucleoside, which had 2-amino group were synthesized, and T_m values with a natural nucleoside were measured.     

Densities and Viscosities of Tris(acetylacetonato)cobalt(III) Complex Solutions in Various Solvents

The densities and the viscosities of tris(acetylacetonato)cobalt(III) solutions in acetonitrile, dichloromethane, chloroform, tetrachloromethane, benzene, toluene, ethylbenzene, and p-xylene were measured in the dilute concentration regions at several temperatures ranging from 278 to 313 K under ambient pressure. The partial molar volumes of the solvents and solute were calculated. They are independent of concentration and increase slightly as the temperature increases. The viscosity A- and B-coefficients of the Jones-Dole equation were obtained. The A-coefficients were found to be zero within experimental error. The B-coefficients are positive and decrease as the temperature increases. Thermodynamic quantities of activation for viscous flow were calculated on the basis of Eyring’s viscosity equation. From the quantities obtained in this study, along with some information from the literature, it is suggested that structure-making interactions occur between the segments of the complex and the solvent molecules. These interactions include electrostatic interactions between the local charge on the complex and the dipole moment of the solvent in solutions of acetonitrile and dichloromethane, interlocking packing interactions along C ₃-axis of the complex with solvent in solutions of chloroform and tetrachloromethane, and π-electron interactions between the chelate ring of the complex and the solvent in solutions of benzene, toluene, ethylbenzene, and p-xylene.     

Spin-oriented projectile fragments: The first application tog-factor measurements

Ejectile nuclei in the fragmentation of intermediate-energy heavy-ion projectiles were found to be largely spin polarized. The observed polarization as a function of the outgoing momentum was nicely explained by a simple kinematical argument based on the participant-spectator model of projectile fragmentation. The measurements extended to cover several different targets, incident energies, exit channels, and emission angles revealed that substantial polarization shows up widely in projectile fragmentation reactions. Furthermore, this polarization exhibits an interesting behavior which may be interpreted as a manifestation of a gradual change in the deflection angle from positive to negative values as the energy increases and/or the target-Z decreases. The present polarization results also suggests various applications of spin polarized radioactive beams. As the first example of such an application, we present a recent result on theg-factor measurements on neutron-rich nuclei.