Evaluation of Deformation-Strength Properties of Volcanic Soils by Laboratory and In-Situ Testings

The present study aims to clarify the deformation-strength properties of natural grounds consisting mainly of volcanic coarse-grained soils. Site investigations using cone penetration test (CPT), standard penetration test (SPT) and seismic cone penetration test (SCT) were performed at three sites in Hokkaido, Japan. In addition to these in-situ tests, a series of cyclic triaxial test on the undisturbed samples taken from their sites were also carried out to obtain the pseudo elastic shear modulus and damping ratio and their dependencies on strain level. From the test data, it was found that; (1) N-values obtained from SPT on crushable volcanic grounds are underestimated with the increase of the number of dynamic penetrations due to the particle breakage, (2) there are the linear relationships among ql from CPT, shear modulus GSC, obtained from SCT and SPT-N value for volcanic soil grounds, and (3) small strain shear modulus obtained from the in-situ and laboratory tests is independent of void ratios of volcanic grounds

H_2 Dissociative Adsorption at the Armchair Edges of Graphite

We investigate and discuss how hydrogen behaves at the edges of a graphite sheet, in particular the armchair edge. Our density functional theory-based calculations results show that, in contrast to the zigzag edge [cf., e-J. Surf. Sci. Nanotech. 2 (2004) 77], regardless of orientation, there is an activation barrier hindering H_2 dissociation at the armchair edges. And once they do get dissociatively adsorbed at the armchair edges, we find that it would be extremely hard to desorb the H from their adsorption sites at the armchair edges. Furthermore, we also found that, consistent with our earlier conclusions [cf., J. Phys. Soc. Jpn. 72 (2003) 1867], it is unlikely that we would find a whole H_2 in between plain graphite sheets.Comment: 4 pages, 5 figures, preprin

Impact of polyplex micelles installed with cyclic RGD peptide as ligand on gene delivery to vascular lesions

Gene therapy is expected to open a new strategy for the treatment of refractory vascular diseases, so the development of appropriate gene vectors for vascular lesions is needed. To realize this requirement with a non-viral approach, cyclo(RGDfK) peptide (cRGD) was introduced to block copolymer, poly(ethylene glycol)-block-polycation carrying ethylenediamine units (PEG-PAsp(DET)). cRGD recognizes αvβ3 and αvβ5 integrins, which are abundantly expressed in vascular lesions. cRGD-conjugated PEG-PAsp(DET) (cRGD-PEG-PAsp(DET)) formed polyplex micelles through complexation with plasmid DNA (pDNA), and the cRGD-PEG-PAsp(DET) micelles achieved significantly more efficient gene expression and cellular uptake as compared with PEG-PAsp(DET) micelles in endothelial cells and vascular smooth muscle cells. Intracellular tracking of pDNA showed that cRGD-PEG-PAsp(DET) micelles were internalized via caveolae-mediated endocytosis, which is associated with a pathway avoiding lysosomal degradation, and that PEG-PAsp(DET) micelles were transported to acidic endosomes and lysosomes via clathrin-mediated endocytosis. Further, in vivo evaluation in rat carotid artery with a neointimal lesion revealed that cRGD-PEG-PAsp(DET) micelles realized sustained gene expression, while PEG-PAsp(DET) micelles facilitated rapid but transient gene expression. These findings suggest that introduction of cRGD to polyplex micelles might create novel and useful functions for gene transfer and contribute to the establishment of efficient gene therapy for vascular diseases