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

Policies to Support Businesses through the COVID-19 Shock: A Firm Level Perspective

Relying on a novel dataset covering more than 120,000 firms in 60 countries, this paper contributes to the debate about policies to support businesses through the COVID-19 pandemic. While governments around the world have implemented a wide range of policy support measures, evidence on the reach of these policies, the alignment of measures with firm needs, and their targeting and effectiveness remains scarce. This paper provides the most comprehensive assessment to date of these issues, focusing primarily on developing economies. It shows that policy reach has been limited, especially for more vulnerable firms and countries, and identifies mismatches between policies provided and policies most sought. It also provides some indicative evidence regarding mistargeting of policies and their effectiveness in addressing liquidity constraints and preventing layoffs. This assessment provides some early guidance to policymakers on tailoring their COVID-19 business support packages and points to new directions in data and research efforts needed to guide policy responses to the current pandemic and future crises

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