Synthesis of glycopolymers bearing mannaric pendants as inhibitors on the β‐glucuronidase activity: The inhibition mechanisms of mannaric‐ and glucaric‐compounds

A new styrene derivative having D ‐mannaric moiety, N‐p‐vinylbenzyl‐D ‐mannaramic acid (VB‐D ‐ManaH, 8 ) was synthesized though the ring‐opening reaction of D ‐mannaro‐1,4:6,3‐dilactone (D ‐MDL) with p‐vinylbenzylamine. VB‐D ‐ManaH was copolymerized with acrylamide (AAm) to give novel polymers having D ‐mannaric moiety in the pendants, P(VB‐D ‐ManaH‐co‐AAm), 10 . The resulting glycomonomer and polymer ( 8 and 10 ) bearing D ‐mannaric pendants were found to inhibit the β‐glucuronidase activity, although the inhibition ability of the corresponding saccharodilactone (D ‐MDL) was known to be low. Additionally, the inhibition ability of P(VB‐D ‐ManaH‐co‐AAm), 10 , was almost the same as that of the glycopolymer having D ‐glucaric pendants, P(VB‐6‐D ‐GlcaH‐co‐AAm), 1 , which was one of the most effective inhibitors for β‐glucuronidase, reported in our previous work. Thus, 10 and 8 may be the first D ‐mannaric strong inhibitors to the β‐glucuronidase activity. The Lineweaver–Burk plot suggested that the inhibition mechanisms of 10 and 8 were more complicated than in the case of the competitive and uncompetitive inhibition of N‐p‐(vinylbenzyl)‐6‐D ‐glucaramic ( 11 ) and N‐p‐(vinylbenzyl)‐1‐D ‐glucaramic acids ( 12 ), respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2032–2042, 2009     

THz imaging of cyclotron emission in quantum Hall conductors

Recent studies of cyclotron emission microscopy on quantum Hall related states are reported. The topics include non-equilibrium between edge and bulk states, current-induced breakdown of the quantum Hall effect, and the emission threshold at hot spots. Experimental method of scanning-type terahertz microscopes developed towards photon-counting level sensitivity is also described.     

Discrimination of ionic pollutants except condensation nuclei of acid fog using an ultrasonic humidifier.

Fog droplets in the atmosphere are first produced by the activation of cloud condensation nuclei (CCN), which are originally some ionic compound. Subsequently, the nuclei grow by vapor diffusion. Fog droplets are polluted through the activation process and successive diffusion growth and residence (post activation). We cannot distinguish the effects of the two pollution processes of natural fog water samples. We found that fog droplets can be produced artificially without CCN using an ultrasonic humidifier. Because the artificial fog droplets are not polluted by CCN, the movement of the fog droplets in natural air will take up some pollutants in the air. Consequently, the two pollution processes of fog (the activation of CCN and the post activation process) can be discriminated using data from field experiments. This sampling analytical method is extremely important for further research regarding fog, clouds and environmental chemistry.     

Functional renormalization group beyond the static approximation and its application to the two-dimensional Hubbard model

While the functional renormalization group is a powerful theoretical method, the static approximation has been usually adopted in which the Matsubara frequency dependence of vertex functions is ignored. We propose a formalism beyond the static approximation with an efficient parameterization in the Matsubara frequency space for the vertex functions to incorporate the self-energy.     

Electrical transport characteristic of carbon nanotube after mass-separated ultra-low-energy oxygen ion beams irradiation

Mass-separated ultra-low-energy oxygen ion beams were irradiated to the single-walled carbon nanotubes (SWCNTs) under an ultra-high-vacuum pressure of 10⁻⁷ Pa for the purpose of achieving n-type conduction of nanotubes. The ion beam energy was 25 eV, which was close to the displacement energy of graphite. The incident angle of the ion beam was normal to the target nanotube. The ion dose ranged from 3.3 × 10¹¹ to 3.8 × 10¹² ions/cm². The structure of SWCNTs after the ion irradiation was investigated. The CNTs still have a clear single-walled structure after the ion irradiation. The graphite structure is distorted and some defects are induced in the nanotube by the oxygen irradiation. The oxygen ions with the ion energy of 25 eV are irradiated to the field effect transistor (FET) device with the nanotube channel. The n-type characteristic appears upon the oxygen ion irradiation, and the device exhibits ambipolar behavior. The defects induced by the ion irradiation may act as the n-type dopants.     

In vivo non-mechanical scanning grating-generated optical coherence tomography using an InGaAs digital camera

We demonstrated in vivo cross-sectional imaging of human fingers by non-mechanical scanning optical coherence tomography (OCT), using a diffracted light as the reference beam and a linear illumination beam at a center wavelength of 1.3 μm for deeper penetration into biological tissues. By applying the three-step phase-shifting method, our system can measure OCT images at 10 frames/s with a sensitivity of 90 dB for a 2.45 × 4.80 mm (axial × lateral) measurement range using an InGaAs digital camera (320 × 256 pixels).     

Enantiopure tert-butyl(phenyl)phosphine oxide. Chirality-recognition ability and mechanism

When enantiopure tert-butyl(phenyl)phosphine oxide 1 was used as a resolving agent, it showed an acceptable to good chirality-recognition ability for several kinds of racemic carboxylic acids 2. A study on a chirality-recognition mechanism based on X-ray crystallographic analyses of the diastereomeric complexes of 2 with 1 revealed that the complex crystals consisted of helical columns and that 1 was not responsible for the formation of the helical column and occupied a void between the columns; although 1 interacted with 2 via a hydrogen bond to primarily form a pair with 2, the complex crystals were mainly stabilized by the accumulation of weak interactions, such as CH/π, π/π and CH?O interactions, between 1/1, 1/2 and 2/2.     

The Structure of Zirconium Oxide in Silica Matrix and its Epoxidation Activity

Zirconia-silica composite oxides were prepared by a sol-gel method, and the state of Zr in the silica matrix was analyzed in relation to its activity in the epoxidation of oct-1-ene with t-butyl hydroperoxide. XAFS analysis suggested that Zr in the composite oxides with low Zr content was in the coordinatively less saturated state compared with those in the oxides with higher Zr contents. Epoxidation of oct-1-ene proceeded effectively on the oxides with low Zr contents. The first step of the epoxidation was assumed to be the interaction of t-butyl hydroperoxide with the coordinatively unsaturated site of Zr.     

The first homology of the group of equivariant diffeomorphisms and its applications

Let V be a representation space of a finite group G. We determinethe group structure of the first homology of the equivariantdiffeomorphism group of V. Then we can apply it to the calculationof the first homology of the corresponding automorphism groupsof smooth orbifolds, compact Hausdorff foliations, codimensionone or two compact foliations and the locally free S¹-actionson 3-manifolds. Received November 5, 2007.