Polyethylenimine-Modified Multiwalled Carbon Nanotubes for Plasmid DNA Gene Delivery

An efficient molecular delivery technique based on the transporting high-molecular-weight PEI 600K-modified multiwalled carbon nanotubes (PEI 600K-MWCNTs) into cell membranes is reported. The PEI 600K-MWCNTs exhibit low cytotoxicity and its associated plasmid DNA (pDNA) is delivered to cells efficiently, and the green fluorescent protein (GFP) levels up to 18 times higher than that of naked DNA were observed

Zero-Mode Contribution in Nucleon-Delta Transition

We investigate the transition form factors between nucleon and $\Delta$(1232) particles by using a covariant quark-spectator-diquark field theory model in (3+1) dimensions. Performing a light-front calculation in parallel with the manifestly covariant calculation in light-front helicity basis, we examine the light-front zero-mode contribution to the helicity components of light-front good ("+") current matrix elements. Choosing the light-front gauge ($\epsilon^+_{h=\pm}=0$) with circular polarization in Drell-Yan-West frame, we find that only the helicity components $({1\over 2}, {1\over 2})$ and $({1\over 2},-{1\over 2})$ of the good current receive the zero-mode contribution. Taking into account the zero-mode, we find the prescription independence in obtaining the light-front solution of form factors from any three helicity matrix elements with smeared light-front wavefunctions. The angular condition, which guarantees the full covariance of different schemes, is recovered.Comment: 16 latex pages, 7 figures, to appear in PR

Boundary motion coupled with tensile and compressive deformation: TEM observation of twinning-like lattice reorientation in Mg micropillars

For magnesium and some other hexagonal-close-packed metals, twinning on the plane is a common mode of plastic deformation. Recently, we have used in situ transmission electron microscopy (TEM) to monitor the deformation of submicron-sized single-crystal magnesium, in quantitative compression and tension tests (B-Y. Liu et al., Nature Commun. 2014). We have observed the reorientation of the parent lattice to a “twin” lattice, producing an orientational relationship akin to that of the conventional twinning. However, aberration-corrected TEM observations reveal that the boundary between the parent lattice and the “twin” lattice is composed of many segments of semi-coherent basal-prismatic (B-P) interfaces, instead of the twinning plane. Both TEM and molecular dynamics simulations suggest that the migration of this boundary is accomplished by B-P interfaces undergoing basal-prismatic transformation, in addition to the migration of the boundary of the extension twin. This deformation mode mimics conventional deformation twinning, but is distinct from the latter. It is a form of boundary motion coupled to stresses, but produces plastic strain that is not simple shear. The basal-prismatic transformation appears to be important under deformation conditions when the availability and/or mobility of twinning dislocations/disconnections are limited. As such, this new twist in lattice reorientation accompanying deformation twinning enriches the known repertoire of plasticity mechanisms

Lattice study on ηc2\eta_{c2} and X(3872)

Properties of $2^{-+}$ charmonium $\eta_{c2}$ are investigated in quenched lattice QCD. The mass of $\eta_{c2}$ is determined to be 3.80(3) GeV, which is close to the mass of $D$-wave charmonium $\psi(3770)$ and in agreement with quark model predictions. The transition width of $\eta_{c2}\to \gamma J/\psi$ is also obtained with a value $\Gamma=3.8(9)$ keV. Since the possible $2^{-+}$ assignment to X(3872) has not been ruled out by experiments, our results help to clarify the nature of X(3872).Comment: 15 pages, 8 figures. typos, grammatical errors and some references corrected, redundant discussions deleted, conclusion does not change. published versio