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Theoretical description of oscillations of electron liquid in large metallic nanospheres (with radius of few tens of nanometer) is formulated within random-phase-approximation semiclassical scheme in jellium model with retardation included via Lorentz friction. Spectrum of plasmons is determined including both surface and volume type excitations. It is demonstrated that only surface plasmons of dipole type can be excited by homogeneous dynamical electric field. The Lorentz friction due to irradiation of electromagnetic wave by plasmon oscillations is analyzed with respect to the sphere dimension. The resulting shift in resonance frequency turns out to be strongly sensitive to the sphere radius. The form of electromagnetic (e-m) response of the system of metallic nanospheres embedded in the dielectric medium is found. The theoretical predictions are verified by a measurement of extinction of light due to plasmon excitations in nanosphere colloidal water solutions, for Au and Ag metallic components with radius from 10 to 75 nm. Theoretical predictions and experiments clearly agree in the positions of surface plasmon resonances and in an emergence of the first volume plasmon resonance in the e-m response of the system for limiting big nanosphere radii, when dipole approximation is not exact. [ABSTRACT FROM AUTHOR]

An electric resistance measurement was used to study the crystallization process of Ge2Sb2Te5 (GST) and N-doped Ge2Sb2Te5 (N-GST) films. The relation between conductivity and annealing time was investigated and the crystallization parameters were determined directly by resistance measurement during isothermal crystallization process in the amorphous GST and the N-GST films. The results show that the crystallization processes in both GST and N-GST films are layer by layer. Their conductivities satisfy the equation σ=σc-(σc-σa)exp(-ktn), at t>τ, where τ is a temperature-dependent time in the process of crystallization. The activation energy for crystallization of amorphous GST films was 2.11±0.18 eV and the Avrami coefficient was between 2 to 4, in close agreement with previous studies using different techniques. After N doping the Avrami coefficient decreased, while the activation energy increased. The formation of a strain induced by the distortion of unit cell after N doping was used to explain the observed results. [ABSTRACT FROM AUTHOR]

High-angle annular dark-field ~HAADF! scanning transmission electron microscopy ~STEM! images of electron-transparent samples show dominant atomic number ~Z-! contrast with a high lateral resolution. HAADF STEM at low electron energies ,30 keV is applied in this work for quantitative composition analyses of InGaAs quantum wells. To determine the local composition, normalized experimental image intensities are compared with results of Monte Carlo simulations. For verification of the technique, InGaAs/GaAs quantumwell structures with known In concentration are used. Transmission electron microscopy samples with known thickness are prepared by the focused-ion-beam technique. The method can be extended to other material systems and is particularly promising for the analysis of materials that are sensitive toward knock-on damage. [ABSTRACT FROM AUTHOR]

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010. [ABSTRACT FROM PUBLISHER]

To explore the potential cause of colorectal cancer metastasis, gene expression profiles, GSE21510, and miRNA expression profiles, GSE48074, were downloaded from the Gene Expression Omnibus database. Differentially expressed genes in metastatic colorectal and non metastatic colorectal cancer compared with the normal samples were identified via the limma package in R. The differentially expressed miRNAs in colorectal cancer samples with lymph node metastasis compared with those without lymph node metastasis were screened out by the some method. Differentially expressed genes that were upregulated in colorectal cancer samples with distant metastasis in comparison to that in samples without distant metastasis and normal samples were considered to play important roles in colorectal cancer metastasis. Functional enrichment analysis of these genes was conducted using the Database for Annotation, Visualization, and Integrated Discovery v6.7. Biological processes related to cell differentiation and cell proliferation were significantly enriched. TF (transcription factor)-miRNA-mRNA regulation loops were constructed by using the starBase and ChIPBase databases. Finally, six critical regulation loops were screened out. They were composed of two TFs, two miRNAs, and three mRNAs. Some of these TFs, mRNAs, or miRNAs have previously been identified as critical targets in colorectal cancer metastasis. Additionally, several new targets were identified in our study, which may be helpful to improve metastatic colorectal cancer treatment.

The number of glucocorticoid receptors (GCR) in peripheral leukocytes was determined by radioligand-binding assay in extrinsic and intrinsic asthmatics. Their corresponding plasma cortisol levels were assessed. The results showed that the average number of GCR in asthmatics was significantly lower than that in healthy subjects (P < 0.01), and there was a linear correlation between the number of GCR and the course of asthma. Besides, there was also a linear correlation between the number of GCR and the age of the initial attack of asthma. No difference in plasma cortisol level was found between asthmatics and healthy subjects. These findings suggest that there is no primary and general impairment of glucocorticoid metabolism in the asthmatics, but the number of GCR in the asthmatics is lower than that in healthy controls. The decrease of the number of GCR in asthmatics, we think, is related to heredity and repeated attacks of asthma.