Preparation and evaluation of polyamidoamine dendrimer (G2)/branched-��-cyclodextrin conjugate as a novel gene transfer carrier

The purpose of this study is to evaluate the potential use of polyamidoamine (PAMAM) starburst dendrimer (generation 2, G2) conjugates with 6-O-??-(4-O-??-d-glucuronyl)-d-glucosyl-??-cyclodextrin (GUG-??-CDE (G2)) having glucose as a spacer between dendrimer and cyclodextrin (CyD) as a novel gene transfer carrier. GUG-??-CDE (G2) was found to have lower hemolytic activity than dendrimer (G2), suggesting that GUG-??-CDE (G2) had lower local irritation than dendrimer (G2). Of GUG-??-CDEs (G2) having the various average degree of substitution (DS) of a glucuronylglycoside group, GUG-??-CDE (G2, DS 1.8) possessed much higher gene transfer activity than ??-CDE (G2, DS 1.2) and ??-CDE (G2, DS 1.3) in A549 and RAW264.7 cells, suggesting the crucial role of a spacer between dendrimer and CyD for high gene transfer activity of GUG-??-CDE (G2, DS 1.8). In sharp contrast to linear polyethyleneimine (10 kDa, PEI), GUG-??-CDE (G2, DS 1.8) had negligible cytotoxicity. These results suggest that GUG-??-CDE (G2, DS 1.8) could have the potential for a novel gene transfer carrier, compared to ??-CDE (G2, DS 1.2), ??-CDE (G2, DS 1.3) and PEI.     

Magnetic field switching between the two orbital-ordered states in DyVO3

The critical phase competition between different spin-orbital-ordered states has been investigated for the DyVO3 single crystal. As temperature is lowered, the compound exhibits a reentrant spin and orbital ordering (SO and OO) transition: C-->G-->C type for SO and G-->C-->G type for OO. It was found that a magnetic field also drives the phase transition from C to G for OO and concomitantly from G to C for SO, the latter of which is coupled with the metamagnetic transition of the Dy 4f moments. The mechanism of this novel magnetic-field-induced orbital switching is discussed.     

Ferroelectric polarization flop in a frustrated magnet MnWO4 induced by a magnetic field

The relationship between magnetic order and ferroelectric properties has been investigated for MnWO4 with a long-wavelength magnetic structure. Spontaneous electric polarization is observed in an elliptical spiral spin phase. The magnetic-field dependence of electric polarization indicates that the noncollinear spin configuration plays a key role for the appearance of the ferroelectric phase. An electric polarization flop from the b direction to the a direction has been observed when a magnetic field above 10 T is applied along the b axis. This result demonstrates that an electric polarization flop can be induced by a magnetic field in a simple system without rare-earth 4f moments.     

Observation of spin reorientation in layered manganites La1.2Sr1.8(Mn1−yRuy)2O7 (0.0⩽y⩽0.2) by Lorentz transmission electron microscopy

The effect of Ru substitution for Mn in bilayered oxides La_1.2Sr_1.8(Mn_1−yRu_y)₂O₇ (0?y?0.2$0?y?0.2$) was investigated by magnetization measurements and low-temperature Lorentz transmission electron microscopy. It was found that the magnetic anisotropy is controlled by the Ru content y and temperature T. The easy axis changes from 〈1 1 0〉 for the y=0$y=0$ crystal to the c  -axis for y=0.2$y=0.2$, and it rotates away from the c-  axis for the y=0.05$y=0.05$ and y=0.07$y=0.07$ crystals with decreasing temperature. Furthermore, maze-shaped magnetic domain structures were observed in the (0 0 1) thin crystals with 0.05?y?0.2$0.05?y?0.2$. Changes in domain size and structure indicate that the uniaxial magnetic anisotropy becomes stronger as Ru content y increases.     

Cycloidal spin order in the a-axis polarized ferroelectric phase of orthorhombic perovskite manganite

The ferroelectric state in an orthorhombic perovskite RMnO3 (R=Gd0.7Tb0.3) was proved by neutron scattering studies to show the cycloidal spin state with the ab-spiral plane and the spin-helicity dependent polarization vector along the a axis, sharing the microscopic origin (inverse Dzyaloshinskii-Moriya interaction) with the more widely observed P||c state (e.g., for R=Tb and Dy) with the bc-spiral plane. The magnetic-field induced polarization flop from P||c to P||a as well known for RMnO3 is thus assigned to the orthogonal flop of the spin spiral plane from bc to ab.     

Extended thermodynamics of real gases with dynamic pressure: An extension of Meixnerʼs theory

Basing on the recent theory of extended thermodynamics of dense gases, we study a thermodynamic theory of gases with the energy transfer from molecular translational mode to internal modes as an extension of Meixner?s theory. We focus our attention on the simplest case with only one dissipative process due to the dynamic pressure. The dispersion relation for sound derived from the present theory is compared with that from Meixner?s theory. Kinetic theoretical basis of the present approach is also discussed.     

Molecular extended thermodynamics of rarefied polyatomic gases and wave velocities for increasing number of moments

Molecular extended thermodynamics of rarefied polyatomic gases is characterized by two hierarchies of equations for moments of a suitable distribution function in which the internal degrees of freedom of a molecule is taken into account. On the basis of physical relevance the truncation orders of the two hierarchies are proven to be not independent on each other, and the closure procedures based on the maximum entropy principle (MEP) and on the entropy principle (EP) are proven to be equivalent.     

Extended thermodynamics of dense gases

We study extended thermodynamics of dense gases by adopting the system of field equations with a different hierarchy structure to that adopted in the previous works. It is the theory of 14 fields of mass density, velocity, temperature, viscous stress, dynamic pressure, and heat flux. As a result, most of the constitutive equations can be determined explicitly by the caloric and thermal equations of state. It is shown that the rarefied-gas limit of the theory is consistent with the kinetic theory of gases. We also analyze three physically important systems, that is, a gas with the virial equations of state, a hard-sphere system, and a van der Waals fluid, by using the general theory developed in the former part of the present work.     

Core polarization effects on the Coulomb form factor

Coulomb form factors for the transitions between single-particle (or -hole) states with LS closed shells are investigated. Core polarization effects are calculated by using microscopic models. Information on the effective interaction which cannot be provided by γ-transition data alone is obtained from the momentum transfer dependence of the form factor. An effective interaction is required not to be repulsive in triplet-odd two-particle states in order to explain the experimental data on ¹⁵N. The bare G-matrix gives a reasonable fit to the data while the phenomenological interaction with Rosenfeld mixture does not. It is also shown that the core polarization effect for the Coulomb form factors with high multipolarity is sensitive to the mixing character of the effective interaction.