Synthesis of [2-C]-oleanolic acid and [2-C]-myricerone

Synthetic way for ¹³C-labeled oleanolic acid 1 and myricerone 2 has been developed, starting from the parent 1 and 2. The procedure involves ring opening and closure of the A rings of these oleanane triterpenes. ¹³C was introduced into the 2-position by ¹³C-MeLi as an isotope source. Chelation controlled addition of methyllithium to -hydoxypentanone 11 is a common crucial step for labeling of 1 and 2, and judicious choice of protecting groups is essential for 2.     

Cluster-Mediated Water Adsorption on Carbon Nanopores

The adsorption isotherms of water at 303 K and N2 at 77 K on various kinds of porous carbons were compared with each other. The saturated amounts of water adsorbed on carbons almost coincided with amounts of N2 adsorption in micropores. Although carbon aerogel samples have mesopores of the great pore volume, the saturated amount of adsorbed water was close to the micropore volume which is much small than the mesopore volume. These adsorption data on carbon aerogels indicated that the water molecules are not adsorbed in mesopores, but in micropores only. The adsorption isotherms of water on activated carbon having micropores of smaller than 0.7 nm in width had no clear adsorption hysteresis, while the water adsorption isotherms on micropores of greater than 0.7 nm had a remarkable adsorption hysteresis above P/P0 = 0.5. The disappearance of the clear hysteresis for smaller micropores suggested that the cluster of water molecules of about 0.7 nm in size gives rise to the water adsorption on the hydrophobic micropores; the formation and the structure of clusters of water molecules were associated with the adsorption mechanism. The cluster-mediated pore filling mechanism was proposed with a special relevance to the evidence on the formation of the ordered water molecular assembly in the carbon micropores by in situ X-ray diffraction.     

Macroporous zirconia particles prepared by subcritical water in batch and flow processes

Porous zirconia particles were synthesized through a low-temperature hydrothermal synthesis process. Under hydrothermal conditions, water can control the direction of crystal growth, morphology, particle size, and size distribution because thermodynamics and transport properties can be controlled by pressure and temperature. In a batch process, the hydrothermal synthesis was conducted at 200–300 °C and 30 MPa with an SUS-304 tube as the reactor. At the same reaction pressure, experiments were also performed for a flow process with temperatures of 180–200 °C. The synthesized products were calcined and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results showed that the macroporous zirconia particles that were formed had pore diameters around 419 nm. The XRD pattern indicated that the products were composed of zirconium oxide particles with monoclinic, tetragonal, and cubic structures.     

Excitation energy dependence for the Li 1s X-ray photoelectron spectra of LiMn2O4.

The Li 1s XPS (X-ray Photoelectron Spectroscopy) spectra of LiMn2O4, which is one of the major positive-electrode materials in lithium-ion rechargeable batteries, and MnO2 as a reference material, were measured by a laboratory-type XPS spectrometer. The Li 1s peak was not observed in the spectra excited by the Mg Kalpha line (1253.6 eV), because the Li 1s peak overlapped the background of the Mn 3p peak of LiMn2O4. The photoionization cross section of Mn 3p was larger than that of Li 1s for Mg Kalpha excitation. Therefore, the XPS measurement of LiMn2O4 by soft X-ray synchrotron excitation was carried out at beamline BL-7B on NewSUBARU synchrotron facility. Excitation energies of 110, 120, 130, 140, 150 and 151.4 eV were selected. The Li 1s peak was clearly observed in these XPS spectra. In order to investigate the excitation energy dependence, the area ratio of the Li 1s and Mn 3p peaks in the XPS spectra was plotted against the excitation energy. As a result, when the excitation energy was 110 eV, the area ratio had the maximum value.     

Measurement of particle distribution in microchannel flow using a 3D-TIRFM technique

The presence of bio-substances in the near-wall region in micro bio-chemical analysis chips is an important topic but one which is difficult to investigate directly. In this paper we developed an accurate 3D-TIRFM technique, which was used to investigate the three-dimensional positions of nano-particles. The depth was calibrated using a piezo stage. As an example of an application of this technique, the concentration profile of nano-particles near a wall surface was investigated. The results showed that the concentration profile was non-uniform and lower than that in the bulk. In addition the ionic strength of the solvent strongly influenced the concentration profile. It was concluded that the non-uniform concentration profile is due to the influence of the electric double layer around the particles and the surface. This demonstrates the importance of selecting suitable electric characteristics, since a non-uniform and low concentration profile near the wall will affect the reaction efficiency and the sensitivity in micro bio-chemical analysis.     

The Third Generation (e,e′K~+) A Hypernuclear Spectroscopy at Jlab

We are now preparing for the third generation (e,e′K~+) A hypernuclear spectroscopic experiment at Hall C,Jefferson Lab (USA).The goal of the experiment is the precise spectroscopy of hypernuclei in wide mass region.We have constructed a new high resolution electron spectrometer "HES" dedicated to (e,e′K~+) hypernuclear study in Japan and it was shipped to JLab in February,2008.We will discuss about the physics of the (e,e′K~+) hypernuclear study at JLab and report the current preparation status of the third generatrion experiment.     

New synthesis of heterocycles by use of palladium catalyzed cycli zation of α-haloamide with internal double bond

α-Haloamide having internal double bond was allowed to react with a catalytic amount of Pd(PPh₃)₄ in the presence of base to produce a cyclized product in a fairly good yield possibly through the intermediate of -alkylmetal complex. By use of this method, five and six membered lactams, pyrrolizidine and quinolizidine derivatives were synthesized in fairly good yields.     

Free vibration of rotating non-uniform discs: Spline interpolation technique calculations

Stress distributions and flexural vibration of rotating annular discs with radially varying thickness are calculated by means of a spline interpolation technique. For this purpose, the disc is divided into many ring-shaped elements and the radial displacement is expressed as a cubic spline function, which satisfies the equation of equilibrium of force at all the knots and also satisfies boundary conditions at both edges. Centrifugal stress distributions are calculated from the radial displacement. The transverse deflection of the disc is expressed as a quintic spline function. The frequency equation is derived from the conditions that this function satisfies the differential equation governing the flexural vibration of the disc at the knots and also satisfies the edge conditions. The method is applied to free-clamped rotating discs with linearly, parabolically and exponentially varying thickness, the natural frequencies and the mode shapes are calculated numerically, and the effects of rotating velocity and variable thickness are discussed.     

Sublimation phenomena of Lennard-Jones fluids in slit nanopores

Using molecular dynamics simulations, The authors studied the solid-vapor coexistence states of Lennard-Jones methane confined in slit-shaped graphite nanopores. Both the intrapore solid and extrapore vapor were simulated using a unit cell which they previously developed. Frozen critical condensates in the pores were cooled stepwise, and the equilibrium vapor pressure was determined at each temperature. The obtained solid-vapor coexistence curves were remarkably lower than that of the bulk phase. Their thermodynamic model successfully predicts the simulation results without the need to introduce any adjustable parameter, and thus proves its reliability.