Wavelength-selective silencing of photocurrent in Au-coated C-60 wire hybrid

A Au-coated C-60 wire device showed wavelength-selective silencing of photocurrent on illumination with 532 nm light.close6

A Synergistic Anti-Diabetic Effect by Ginsenosides Rb1 and Rg3 through Adipogenic and Insulin Signaling Pathways in 3T3-L1 Cells

Although ginsenosides Rb1 and Rg3 have been identified as the significant ginsenosides found in red ginseng that confer anti-diabetic actions, it is unclear whether insulin-sensitizing effects are mediated by the individual compounds or by their combination. To determine the effect of ginsenosides Rb1 and Rg3 on adipocyte differentiation, 3T3-L1 preadipocytes were induced to differentiate the standard hormonal inducers in the absence or presence of ginsenosides Rb1 or Rg3. Additionally, we determined the effects of Rb1, Rg3, or their combination on the expression of genes related to adipocyte differentiation, adipogenic transcription factors, and the insulin signaling pathway in 3T3-L1 cells using semi-quantitative RT-PCR. Rb1 significantly increased the expression of CEBP alpha, PPAR gamma, and aP2 mRNAs. However, Rg3 exerted its maximal stimulatory effect on these genes at 1 mu M concentration, while a high concentration (50 mu M) showed inhibitory effects. Similarly, treatment with Rb1 and Rg3 (1 mu M) increased the expression of IRS-1, Akt, PI3K, GLUT4, and adiponectin. Importantly, co-treatment of Rb1 and Rg3 (9:1) induced the maximal expression levels of these mRNAs. Our data indicate that the anti-diabetic activity of red ginseng is, in part, mediated by synergistic actions of Rb1 and Rg3, further supporting the significance of minor Rg3

Spatially resolved penetration depth measurements and vortex manipulation in the ferromagnetic superconductor ErNi2B2C

We present a local probe study of the magnetic superconductor, ErNi$_2$B$_2$C, using magnetic force microscopy at sub-Kelvin temperatures. ErNi$_2$B$_2$C is an ideal system to explore the effects of concomitant superconductivity and ferromagnetism. At 500 mK, far below the transition to a weakly ferromagnetic state, we directly observe a structured magnetic background on the micrometer scale. We determine spatially resolved absolute values of the magnetic penetration depth $\lambda$ and study its temperature dependence as the system undergoes magnetic phase transitions from paramagnetic to antiferromagnetic, and to weak ferromagnetic, all within the superconducting regime. In addition, we estimate the absolute pinning force of Abrikosov vortices, which shows a position- and temperature dependence as well, and discuss the possibility of the purported spontaneous vortex formation

Breakdown of the interlayer coherence in twisted bilayer graphene

Coherent motion of the electrons in the Bloch states is one of the fundamental concepts of the charge conduction in solid state physics. In layered materials, however, such a condition often breaks down for the interlayer conduction, when the interlayer coupling is significantly reduced by e.g. large interlayer separation. We report that complete suppression of coherent conduction is realized even in an atomic length scale of layer separation in twisted bilayer graphene. The interlayer resistivity of twisted bilayer graphene is much higher than the c-axis resistivity of Bernal-stacked graphite, and exhibits strong dependence on temperature as well as on external electric fields. These results suggest that the graphene layers are significantly decoupled by rotation and incoherent conduction is a main transport channel between the layers of twisted bilayer graphene.Comment: 5 pages, 3 figure

Hematogenous Metastasis of Ovarian Cancer: Rethinking Mode of Spread

SummaryOvarian cancer has a clear predilection for metastasis to the omentum, but the underlying mechanisms involved in ovarian cancer spread are not well understood. Here, we used a parabiosis model that demonstrates preferential hematogenous metastasis of ovarian cancer to the omentum. Our studies revealed that the ErbB3-neuregulin 1 (NRG1) axis is a dominant pathway responsible for hematogenous omental metastasis. Elevated levels of ErbB3 in ovarian cancer cells and NRG1 in the omentum allowed for tumor cell localization and growth in the omentum. Depletion of ErbB3 in ovarian cancer impaired omental metastasis. Our results highlight hematogenous metastasis as an important mode of ovarian cancer metastasis. These findings have implications for designing alternative strategies aimed at preventing and treating ovarian cancer metastasis

Studies of porous semiconducting materials and their applications in nanotechnology

In this thesis, a variety of studies about the effect of organic monolayers on the light emitting properties of porous silicon (PS), electrochemical applications for the preparation and patterning of porous semiconducting materials such as PS, porous germanium (PG), and semiconducting metal oxides (ZnO, CeO, Cr2O3) are described. A simple technique for preparation of noble metal nanoparticles is also developed. The PS samples functionalized with alkynes or alkenes by various reaction techniques show improved light emitting properties with increased lifetimes. The other important effect of functionalization of PS surface on ECL is to decrease the induction time. For the PS functionalized by anodic electrografting (AEG) recycles ECL about 10 times by applying a brief 10 s of a cathodic bias. It is also remarkable that PG, PS\u27s congener, has been prepared by a novel bipolar electrochemical etching (BEE) technique from an ethanolic HCl electrolyte system. Both positive and negative microscale patterns of semiconducting metal oxides are efficiently and rapidly prepared on flat Si (100) surfaces via a simple photo-assisted bipolar electrochemical process. Selective crystallization of three different metal oxides, ZnO, CeO2, or Cr2O 3 can be achieved in a straightforward manner by a short (5 s) anodic current prior to the cathodic electrodeposition with illumination through a photomask. Lastly, a new technique for preparation of noble metal nanoparticles on semiconducting (Ge) or metallic (Cu, Al, In, Sn, Zr, Zn) surfaces is developed. Redox-derived electroless deposition process is combined with nanolithography techniques, such as dip-pen nanolithography or soft lithography (μ-CP, micro-contact printing), to prepare nanoarchitectures

Chemical Vapor Deposition as a Novel Method for Synthesizing Two-Dimensional Conductive Metal-Organic Frameworks Thin Films

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Study of THF solvated electrons formation via potassium dissolution by mass spectroscopy

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