Microwave assisted synthesis of heterometallic 3d-4f M4Ln complexes

In this paper we describe the synthesis and magnetic properties of a series of 3d-4f complexes of general formula [M4Ln(OH)2(chp)4(SALOH)5(H2O)(MeCN)(Solv)] (Solv = MeOH, MeCN, H2O; chp stands for deprotonated 6-chloro-2-hydroxypyridine (C5H3ClNO), SALOH stands for monodeprotonated 3,5-ditert-butylsalicylic acid (C15H21O3)) obtained by a solvent-free microwave assisted synthesis method. The Ni(II) complexes (Ni4Gd, Solv = MeOH; Ni4Dy, Solv = MeCN) are not SMMs in the absence of an applied dc field. The replacement of Ni(II) by Co(II) (Co4La, Solv = MeOH; Co4Gd, Solv = H2O; Co4Gd-MeCN, Solv = MeCN; Co4Tb, Solv = MeOH; Co4Dy, Solv = H2O) results in improved SMM properties

A Transfer Hamiltonian Model for Devices Based on Quantum Dot Arrays

We present a model of electron transport through a random distribution of interacting quantum dots embedded in a dielectric matrix to simulate realistic devices. The method underlying the model depends only on fundamental parameters of the system and it is based on the Transfer Hamiltonian approach. A set of noncoherent rate equations can be written and the interaction between the quantum dots and between the quantum dots and the electrodes is introduced by transition rates and capacitive couplings. A realistic modelization of the capacitive couplings, the transmission coefficients, the electron/hole tunneling currents, and the density of states of each quantum dot have been taken into account. The effects of the local potential are computed within the selfconsistent field regime. While the description of the theoretical framework is kept as general as possible, two specific prototypical devices, an arbitrary array of quantum dots embedded in a matrix insulator and a transistor device based on quantum dots, are used to illustrate the kind of unique insight that numerical simulations based on the theory are able to provide

Phenotypic and genetic characterization of a novel phenotype in pigs characterized by juvenile hairlessness and age dependent emphysema

<p>Abstract</p> <p>Background</p> <p>A pig phenotype characterized by juvenile hairlessness, thin skin and age dependent lung emphysema has been discovered in a Danish pig herd. The trait shows autosomal co-dominant inheritance with all three genotypes distinguishable. Since the phenotype shows resemblance to the integrin β₆-/- knockout phenotype seen in mice, the two genes encoding the two subunits of integrin α_vβ₆, i.e. <it>ITGB6 </it>and <it>ITGAV</it>, were considered candidate genes for this trait.</p> <p>Results</p> <p>The mutated pig phenotype is characterized by hairlessness until puberty, thin skin with few hair follicles and absence of <it>musculi arrectores pili</it>, and at puberty or later localized areas of emphysema are seen in the lungs. Comparative mapping predicted that the porcine <it>ITGB6 </it>and<it>ITGAV </it>orthologs map to SSC15. In an experimental family (n = 113), showing segregation of the trait, the candidate region was confirmed by linkage analysis with four microsatellite markers. Mapping of the porcine <it>ITGB6 </it>and <it>ITGAV </it>in the IMpRH radiation hybrid panel confirmed the comparative mapping information. Sequencing of the <it>ITGB6 </it>and <it>ITGAV </it>coding sequences from affected and normal pigs revealed no evidence of a causative mutation, but alternative splicing of the <it>ITGB6 </it>pre-mRNA was detected. For both <it>ITGB6 </it>and <it>ITGAV </it>quantitative PCR revealed no significant difference in the expression levels in normal and affected animals. In a western blot, ITGB6 was detected in lung protein samples of all three genotypes. This result was supported by flow cytometric analyses which showed comparable reactions of kidney cells from affected and normal pigs with an integrin α_vβ₆monoclonal antibody. Also, immunohistochemical staining of lung tissue with an integrin β₆antibody showed immunoreaction in both normal and affected pigs.</p> <p>Conclusion</p> <p>A phenotype resembling the integrin β₆-/- knockout phenotype seen in mice has been characterized in the pig. The candidate region on SSC15 has been confirmed by linkage analysis but molecular and functional analyses have excluded that the mutated phenotype is caused by structural mutations in or ablation of any of the two candidate genes.</p

A Transfer Hamiltonian Model for Devices Based on Quantum Dot Arrays

We present a model of electron transport through a random distribution of interacting quantum dots embedded in a dielectric matrix to simulate realistic devices. The method underlying the model depends only on fundamental parameters of the system and it is based on the Transfer Hamiltonian approach. A set of noncoherent rate equations can be written and the interaction between the quantum dots and between the quantum dots and the electrodes is introduced by transition rates and capacitive couplings. A realistic modelization of the capacitive couplings, the transmission coefficients, the electron/hole tunneling currents, and the density of states of each quantum dot have been taken into account. The effects of the local potential are computed within the self-consistent field regime. While the description of the theoretical framework is kept as general as possible, two specific prototypical devices, an arbitrary array of quantum dots embedded in a matrix insulator and a transistor device based on quantum dots, are used to illustrate the kind of unique insight that numerical simulations based on the theory are able to provide

Residual Stress Relaxation Induced by Mass Transport Through Interface of the Pd/SrTiO3

Metal interconnections having a small cross-section and short length can be subjected to very large mass transport due to the passing of high current densities. As a result, nonlinear diffusion and electromigration effects which may result in device failure and electrical instabilities may be manifested. Various thicknesses of Pd were deposited over SrTiO3 substrate. Residual stress of the deposited film was evaluated by measuring the variation of d-spacing versus sin2ψ through conventional X-ray diffraction method. It has been found that the lattice misfit within film and substrate might be relaxed because of mass transport. Besides, the relation between residual intrinsic stress and oxygen diffusion through deposited film has been expressed. Consequently, appearance of oxide intermediate layer may adjust interfacial characteristics and suppress electrical conductivity by increasing electron scattering through metallic films

Comparison of American mink embryonic stem and induced pluripotent stem cell transcriptomes

BACKGROUND: Recently fibroblasts of many mammalian species have been reprogrammed to pluripotent state using overexpression of several transcription factors. This technology allows production of induced pluripotent stem (iPS) cells with properties similar to embryonic stem (ES) cells. The completeness of reprogramming process is well studied in such species as mouse and human but there is not enough data on other species. We produced American mink (Neovison vison) ES and iPS cells and compared these cells using transcriptome analysis. RESULTS: We report the generation of 10 mink ES and 22 iPS cell lines. The majority of the analyzed cell lines had normal diploid chromosome number. The only ES cell line with XX chromosome set had both X-chromosomes in active state that is characteristic of pluripotent cells. The pluripotency of ES and iPS cell lines was confirmed by formation of teratomas with cell types representing all three germ layers. Transcriptome analysis of mink embryonic fibroblasts (EF), two ES and two iPS cell lines allowed us to identify 11831 assembled contigs which were annotated. These led to a number of 6891 unique genes. Of these 3201 were differentially expressed between mink EF and ES cells. We analyzed expression levels of these genes in iPS cell lines. This allowed us to show that 80% of genes were correctly reprogrammed in iPS cells, whereas approximately 6% had an intermediate expression pattern, about 7% were not reprogrammed and about 5% had a "novel" expression pattern. We observed expression of pluripotency marker genes such as Oct4, Sox2 and Rex1 in ES and iPS cell lines with notable exception of Nanog. CONCLUSIONS: We had produced and characterized American mink ES and iPS cells. These cells were pluripotent by a number of criteria and iPS cells exhibited effective reprogramming. Interestingly, we had showed lack of Nanog expression and consider it as a species-specific feature