Ferromagnetic Domain Structure of La0.78Ca0.22MnO3 Single Crystals

The magneto-optical technique has been employed to observe spontaneous ferromagnetic domain structures in La0.78Ca0.22MnO3 single crystals. The magnetic domain topology was found to be correlated with the intrinsic twin structure of the investigated crystals. With decreasing temperature the regular network of ferromagnetic domains undergoes significant changes resulting in apparent rotation of the domain walls in the temperature range of 70-150 K. The apparent rotation of the domain walls can be understood in terms of the Jahn-Teller deformation of the orthorhombic unit cell, accompanied by additional twinning.Comment: 7 pages, 5 figures, to be published in PR

Nonequilibrium 1/f Noise in Low-doped Manganite Single Crystals

1/f noise in current biased La0.82Ca0.18MnO3 crystals has been investigated. The temperature dependence of the noise follows the resistivity changes with temperature suggesting that resistivity fluctuations constitute a fixed fraction of the total resistivity, independently of the dissipation mechanism and magnetic state of the system. The noise scales as a square of the current as expected for equilibrium resistivity fluctuations. However, at 77 K at bias exceeding some threshold, the noise intensity starts to decrease with increasing bias. The appearance of nonequilibrium noise is interpreted in terms of bias dependent multi-step indirect tunneling.Comment: 4pages, 3figures,APL accepte

Correlation structure in nondipole photoionization

The nondipole parameters that characterize the angular disribution of the photoelectrons from the 3d subshell of Cs are found to be altered qualitatively by the inclusion of correlation in the form of interchannel coupling between the $3d_{3/2}$ and $3d_{5/2}$ photoionization channels. A prominent characteristic maximum is predicted only in the parameters for $3d_{5/2}$ photoionization, while the effect for $3d_{3/2}$ is rather weak. The results are obtained within the framework of the Generalized Random Phase Approximation with Exchange (GRPAE), which in addition to the RPAE effects takes into account the rearrangement of all atomic electrons due to the creation of a 3d vacancy

Anterior mitral leaflet perforation identified by real time three-dimensional transesophageal echocardiography

With its unique en face view, real time three-dimensional transesophageal echocardiography has been reported to be more precise than conventional two-dimensional studies in evaluating mitral regurgitation etiology, and can locate diseased segments correctly. We present a case with severe mitral regurgitation due to anterior mitral leaflet perforation. Intraoperative real time three-dimensional transesophageal echocardiography demonstrated its value in diagnosis and surgical planning for this perforation, which had not been identified preoperatively. This technique should be applied more widely for dedicated mitral valve assessment in clinical practice. (Cardiol J 2012; 19, 1: 89–91

High-performance and long-term stability of mesoporous Cu-doped TiO2 microsphere for catalytic CO oxidation

Although the low-temperature reaction mechanism of catalytic CO oxidation reaction remains unclear, the active sites of copper play a crucial role in this mechanism. One-step aerosol-assisted self-assembly (AASA) process has been developed for the synthesis of mesoporous Cu-doped TiO2 microspheres (CuTMS) to incorporate copper into the TiO2 lattice. This strategy highly enhanced the dispersion of copper from 41.10 to 83.65%. Long-term stability of the as-synthesized CuTMS materials for catalytic CO oxidation reaction was monitored using real-time mass spectrum. Isolated CuO and Cu-O-Ti were formed as determined by X-ray photoelectron spectroscopy (XPS). The formation of the Cu-O-Ti bonds in the crystal lattice changes the electron densities of Ti(IV) and O, causing a subsequent change in Ti(III)/Ti(IV) and Onon/OTotal ratio. 20CuTMS contained the highest lattice distortion (0.44) in which the Onon/OTotal ratio is lowest (0.18). This finding may be attributed to the absolute formation of the Cu-O-Ti bonds in the crystal lattice. However, the decrease of Ti(III)/Ti(IV) ratio to about 0.35 of 25CuTMS was caused by the CuO cluster formation on the surface. N2O titration-assisted H2 temperature-programmed reduction and in-situ Fourier transform infrared spectroscopy revealed the properties of copper and effects of active sites

Delivery of proteins in live cells with viral peptides: principles and mechanisms

Cell-penetrating peptides (CPPs) mediate the delivery of macromolecules across the plasma membrane of live cells. These peptides are therefore important due to the potential of making the delivery of protein probes or therapeutics a routine procedure. However, CPP-mediated delivery is currently an inefficient process. CPP-protein conjugates are internalized into cells by endocytosis and the macromolecules remain trapped inside endosomes instead of reaching the target cellular localization. To solve this problem, we report a delivery methodology which relies on the use of a chimera of the TAT and of the Influenza HA2. TAT is a prototypical CPP that can promote macropinocytosis in live cells and HA2 is a pH-sensitive peptide that destabilizes lipid membranes upon acidification. I demonstrate that HA2-TAT can deliver a variety of macromolecular cargos into live mammalian cells by a simple co-incubation protocol. A model is described where TAT causes the endocytic uptake of cargos present in the media and that HA2 disrupts the endosomal membrane upon endosomal acidification. In addition, using red blood cells as a model system, HA2-TAT binds to membranes in a pH-dependent manner and causes the formation of pores through which macromolecules can diffuse. Additionally, the pro-apoptotic domain (PAD) peptide is also successfully delivered by HA2-TAT and shows significant apoptosis in cells through macropinocytosis