Regeneration of atp by immobilized microbial cells and its utilization for the synthesis of ATP and CDP-Choline

A number of fermentative methods for the production of various important nucleotides from their precursors have been developed in Japan, and some of these nucleotides have been industrially produced for more than a decade. For the production of these nucleotides, required ATP is usually supplied to the fermentation media either exogenously or by the naturally occurring ATP regenerating system involved in microbial cells. In this paper, the authors describe an attempt to immobilize ATP-regenerating microbial cells and then utilize such immobilized cells for the continuous production of various nucleotides.     

Direct experimental evidence of exciton-phonon bound states in carbon nanotubes

We present direct experimental observation of exciton-phonon bound states in the photoluminescence excitation spectra of isolated single-walled carbon nanotubes (SWNT) in aqueous suspension. The photoluminescence excitation spectra from several distinct SWNTs show the presence of at least one sideband related to the tangential modes, lying 0.2 eV above the main absorption or emission peak. Both the energy position and line shapes of the sidebands are in excellent agreement with recent calculations [Phys. Rev. Lett. 94, 027402 (2005)] that predict the existence of exciton-phonon bound states, a sizable spectral weight transfer to these exciton-phonon complexes, and that the amount of this transfer depends on the specific nanotube structure and diameter.     

A novel, mild, and facile method to prepare 6-methylidene penem derivatives

A novel and mild method was established to synthesize 6-methylidene penem compounds. This method entails a MgBr(2)/Et(3)N-promoted aldol-type condensation on 6-bromopenem 12 with an appropriately substituted aldehyde to yield the intermediate acetylated bromohydrin, which was smoothly converted to the final product with simultaneous deprotection of C3 carboxylic acid ester using activated zinc dust and phosphate buffer at pH 6.5. This process provides a useful variation of C-C bond formation method for penem derivatives and also serves as a practical synthetic method to prepare 6-exomethylenepenem derivatives without racemization at the C5 position.     

Third and fourth optical transitions in semiconducting carbon nanotubes

We have studied the optical transition energies of single-wall carbon nanotubes over broad diameter (0.7-2.3 nm) and energy (1.26-2.71 eV) ranges, using their radial breathing mode Raman spectra. We establish the diameter and chiral angle dependence of the poorly studied third and fourth optical transitions in semiconducting tubes. Comparative analysis between the higher lying transitions and the first and second transitions show two different diameter scalings. Quantum mechanical calculations explain the result showing strongly bound excitons in the first and second transitions and a delocalized electron wave function in the third transition.     

Effect of Cation Arrangement on the Magnetic Properties of Lithium Ferrites (LiFeO2) Prepared by Hydrothermal Reaction and Post-annealing Method

The magnetic properties of several LiFeO₂polymorphs (different cation arrangements in a cubic close-packed oxygen structure) have been examined by magnetic susceptibility measurements and Mössbauer spectroscopy. Samples with relatively low ferromagnetic impurity levels have been obtained by hydrothermal reaction of FeCl₃·6H₂O or FeOOH with LiOH·H₂O and subsequent annealing in air.α-NaFeO₂with no detectable ferromagnetic impurity has been obtained by hydrothermal reaction ofα-FeOOH and NaOH. Whileα-NaFeO₂revealed only one anomaly at 11 K (Néel point) in the magnetic susceptibility–temperature curves, each LiFeO₂sample shows two anomalies (40–50 and 90–280 K). Mössbauer data confirm that iron is present in the high-spin 3+ state according to the values of the internal field at 4.2 K and isomer shifts at 300 K. The relationship between the cation arrangements and the Néel temperature is discussed for LiFeO₂.     

Die Synthese von 2,3,4,5-1H-Tetrahydroimidazo[2,1-b]chinazolin-2,5-dionen und analogen 2,3,4,5-1H-Tetrahydroimidazo[1,2-a]thieno[2,3-d] (bzw. [3,2-d])-pyrimidin-2,5-dionen

The Synthesis of 2,3,4,5-1H-Tetrahydroimidazo[2,1-b]quinazolin-2,5-diones and analogous 2,3,4,5-1H-Tetrahydroimidazo[1,2-a]thieno[2,3-d] (or [3,2-d])-pyrimidin-2,5-diones The syntheses of various imidazo [2, 1-b]quinazolinediones and their thiophene analogs are described.     

Formation of undulated lamellar structure from ABC block terpolymer blends with different chain lengths

The effect of molecular weight distribution of ABC linear terpolymers on the formation of periodic structures was investigated. Three poly(isoprene-b-styrene-b-2-vinylpridine) triblockterpolymers with molecular weights of 26k, 96k, and 150k were blended variously. Three-phase, four-layer lamellar structures were observed when polydispersity index (PDI) was low, but it has been found that simple lamellar structure with flat surface transforms into an undulated lamellar one, where two interfaces, i.e., I/S and S/P, are both undulated, and they are synchronizing each other if PDI exceeds the critical value. This new structure could be formed due to the periodic and "weak" localization of three chains along the domain interfaces, which produces periodic surfaces with nonconstant mean curvatures. With further increase of PDI, the blend macroscopically phase-separated into different microphase-separated structures.