Systematic Measurement of pd Breakup Cross Section Around Space Star

Space Star (SS) anomaly in nd breakup cross section was first reported in 1989 at E _n = 13 MeV (Strate et al. in Nucl Phys A 501:51, 1989), but its origin has not been found yet. In order to obtain suggestions for its origin, we made systematic measurements of pd breakup cross section around SS. In SS configuration, three outgoing nucleons form an equilateral triangle and the triangle is perpendicular to the beam axis. Necessity of the equilateral and perpendicular conditions of SS anomaly was investigated by systematic experiments. Also energy dependence of SS anomaly is being studied at energies from E _p = 7.5 to 13 MeV.     

A Unique Pathway for the 3-Aminobutyrate Starter Unit from l-Glutamate through β-Glutamate during Biosynthesis of the 24-Membered Macrolactam Antibiotic, Incednine

Incednine is a 24-membered macrolactam antibiotic produced by Streptomyces sp. ML694-90F3. A previous study demonstrated that its unique nitrogen-containing starter unit was derived from l-glutamate. To elucidate the missing link between l-glutamate and the starter unit, deuterium labeled amino acid feeding experiments were conducted. These experiments revealed that 3-[3-(2)H]aminobutyrate and β-[2,2,4,4-(2)H(4)]glutamate were incorporated into the starter moiety. The results indicate that a novel decarboxylation of β-glutamate to give 3-aminobutyrate is involved in incednine biosynthesis.     

Synthesis and Structure–Activity Relationship of Vicenistatin,a Cytotoxic 20‐Membered Macrolactam Glycoside

We have developed two syntheses of vicenistatin and its analogues. Our first‐generation strategy included the rapid and sequential assembly of the macrocyclic lactam by using an intermolecular Horner–Wadsworth–Emmons reaction between the C3–C13 fragment and the C1–C2, C14–C19 fragment, followed by an intramolecular Stille coupling reaction. The second‐generation strategy utilized a ring‐closing metathesis of a hexaene intermediate to generate the desired 20‐membered macrolactam. This second‐generation strategy made it possible to prepare synthetic analogues of vicenistatin, including the C20‐ and/or C23‐demethyl analogues. Evaluation of the cytotoxic effect of these analogues indicated the importance of the fixed conformation of aglycon for determining the biological activity of the vicenistatins.     

Robust parameter estimation with a small bias against heavy contamination

In this paper we consider robust parameter estimation based on a certain cross entropy and divergence. The robust estimate is defined as the minimizer of the empirically estimated cross entropy. It is shown that the robust estimate can be regarded as a kind of projection from the viewpoint of a Pythagorean relation based on the divergence. This property implies that the bias caused by outliers can become sufficiently small even in the case of heavy contamination. It is seen that the asymptotic variance of the robust estimator is naturally overweighted in proportion to the ratio of contamination. One may surmise that another form of cross entropy can present the same behavior as that discussed above. It can be proved under some conditions that no cross entropy can present the same behavior except for the cross entropy considered here and its monotone transformation.     

Development and commercialization of ionic-type photosensitive polyimides

Toray's ionic-type photosensitive polyimide, “Photoneece”, is widely used as an interdielectric and as a protection layer for microelectronics, because of its properties, such as the removal of photoreactive groups at low temperature, excellent thermal, mechanical and electrical film properties and excellent adhesion to various substrates. Toray has developed a new type of “Photoneece”, UR-5100, which is a low-stress photosensitive polyimide. In addition to a low thermal expansion coefficient (25 ppm/°C), “Photoneece” UR-5100 also features high resolution with an aspect ratio of more than 2.0 in 40 μm imaged film, and excellent mechanical properties in the cured film such as high elongation (>20%) and tensile strength (>200 MPa), even after 60 hr heat treatment at 350°C. “Photoneece” UR-5100 can be applied in multichip modules (MCMs), hybrid circuits, ICs and LSIs. In this paper the characterization and processing of this “Photoneece” UR-5100 are described.     

Microscopic structures of adsorbed cationic porphyrins on clay surfaces: molecular alignment in artificial light-harvesting systems

The intercalation behavior of cationic porphyrin derivatives within the interlayer spaces of nano-layered clay minerals has been investigated. The porphyrins were successfully intercalated by the newly adopted method of repeated freeze-thaw cycles. The absorption spectra of the porphyrins were compared in the solution phase, adsorbed onto the exfoliated clay nano-sheets, intercalated within the interlayer spaces of clay sheets dispersed in water and intercalated in dry films. Substantial red shifts of the λ_max values in the absorption spectra of the porphyrins were observed on the exfoliated clay sheets, and further red shifts were induced within the interlayer space. The dry films of the intercalated samples exhibited the largest red shifts. X-ray diffraction studies revealed that the clearance space between the layers in these intercalated hybrid compounds is only large enough for the porphyrins to be rigidly packed parallel to the clay layer. For the exfoliated clay nano-sheets, theoretical calculations were carried out on the correlation between the dihedral angle of the meso-substituted pyridiniumyl plane vs. the porphyrin ring and the λ_max of the porphyrin Soret band. An extrapolation of the experimental λ_max value to the correlation curve, afforded the dihedral angle to be 61.6°. The microscopic structure of the adsorbed state of the cationic porphyrins on the exfoliated clay nano-sheets was, thus, proposed to involve an orientation parallel to the clay surface, with a distance of 0.15 nm from the surface, which implies the expulsion of the solvent water molecules.     

Determination of tryptophan and its metabolites in human plasma and serum by high-performance liquid chromatography with automated sample clean-up system

An automated high-performance liquid chromatographic method that incorporates direct injection of biological samples followed by chromatographic sample clean-up in a precolumn is described for the determination of tryptophan and its metabolites in human plasma and serum. The system gave reproducible data with a coefficient of variation of less than 3% with a sample size of 100 microliters of human plasma. The major tryptophan metabolites found in 100 microliters of human plasma were kynurenine, indolelactic acid, indoleacetic acid, indolepropionic acid, serotonin and 5-hydroxyindoleacetic acid. The level of tryptophan and kynurenine in individuals was constant in comparison with other metabolites. Analysis of samples from normal controls, diabetics, gravida and their foetuses showed a tendency for tryptophan metabolites to be low in maternal plasma.     

Reactions of benzylchlorobis(triphenylphosphine)palladium(II) with dimethyl acetylenedicarboxylate

Benzylchlorobis(triphenylphosphine)palladium(II) reacted with dimethyl acetylenedicarboxylate to give [Pd[C(CO₂Me)=C(CH₂Ph)(CO₂Me)]Cl(PPh₃)₂] (II) and [(Ph₃P)ClPdμ-C(CO₂Me)=C(CO₂Me)PdCl(PPh₃) (III). Complexes II and III reacted with Tl(acac) to afford [PdC(CO₂Me=C(CH₂Ph)(CO₂Me)-(acac)(PPh₃)] and [(Ph₃P)(acac)Pdμ-C(CO₂Me)=C(CO₂Me)Pd(acac)(PPh₃)], respectively.