147 research outputs found

    Reversing non-local transport through a superconductor by electromagnetic excitations

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    Superconductors connected to normal metallic electrodes at the nanoscale provide a potential source of non-locally entangled electron pairs. Such states would arise from Cooper pairs splitting into two electrons with opposite spins tunnelling into different leads. In an actual system the detection of these processes is hindered by the elastic transmission of individual electrons between the leads, yielding an opposite contribution to the non-local conductance. Here we show that electromagnetic excitations on the superconductor can play an important role in altering the balance between these two processes, leading to a dominance of one upon the other depending on the spatial symmetry of these excitations. These findings allow to understand some intriguing recent experimental results and open the possibility to control non-local transport through a superconductor by an appropriate design of the experimental geometry.Comment: 6 pages, 3 figure

    Molecular, spectroscopic, and magnetic properties of cobalt(II) complexes with heteroaromatic N(O)-donor ligands

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    New [Co(SCN)2(L)4/2] complexes, where L = b-pic (1), pyCH2OH (2), py(CH2)3OH (3), 1,2,4- triazolo[1,5-a]pyrimidine (4), [CoCl2(urotrop)2] (5), and [Co(DMIM)3]Cl2 H2O (6) where urotrop = hexamethylenetetramine and DMIM = 2,20-bis(4,5-dimethylimidazolyl) were synthesized in simple reactions of CoCl2 6H2O with ammonia thiocyanate and pyridine type ligands or urotropine and diimidazolyl ligands with cobalt(II) chloride in methanol solutions. The orthorhombic crystallization for (1), (2), and (4), the monoclinic one for (3) and (5) as well as the hexagonal one for (6) were found. The plots of the overlap population density-of-states indicated nonbonding character of the interactions between pyridine derivatives ligands and cobalt(II) ions in the complexes (1)–(4). The electronic spectra showed almost perfect octahedral complex in the case of (6). The magnetic susceptibility measurements revealed paramagnetic behavior with low values of the Curie–Weiss temperature, positive for complex (5) and negative for the other ones, although the transition to collective magnetic state at low temperatures for (4) and (5) was evidenced by an observation of antiferromagnetic coupling with Ne´el temperature of 4.5 K and the ferromagnetic one with Curie temperature of 10 K, respectively

    Regular Exercise or Changing Diet Does Not Influence Aortic Valve Disease Progression in LDLR Deficient Mice

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    BACKGROUND: The development and progression of calcific aortic valve disease (CAVD) shares a number of similarities with atherosclerosis. Recently we could demonstrate that regular exercise training (ET) as primary prevention prevents aortic valve disease in LDL-receptor deficient (LDLR(-/-)) mice. We aimed to investigate the impact of exercise training on the progression of CAVD in LDLR(-/-) mice in the setting of secondary prevention METHODS AND RESULTS: Sixty-four LDLR(-/-) mice were fed with high cholesterol diet to induce aortic valve sclerosis. Thereafter the animals were divided into 3 groups: group 1 continuing on high cholesterol diet, group 2 continuing with cholesterol diet plus 1 h ET per day, group 3 continuing with normal mouse chow. After another 16 weeks the animal were sacrificed. Histological analysis of the aortic valve thickness demonstrated no significant difference between the three groups (control 98.3±4.5 µm, ET 88.2±6.6 µm, change in diet 87.5±4.0). Immunohistochemical staining for endothelial cells revealed a disrupted endothelial cell layer to the same extend in all groups. Furthermore no difference between the groups was evident with respect to the expression of inflammatory, fibroblastic and osteoblastic markers. CONCLUSION: Based on the present study we have to conclude that once the development of a CAVD is initiated, exercise training or a change in diet does not have the potential to attenuate the progress of the CAVD

    Emergent Properties of Patch Shapes Affect Edge Permeability to Animals

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    Animal travel between habitat patches affects populations, communities and ecosystems. There are three levels of organization of edge properties, and each of these can affect animals. At the lowest level are the different habitats on each side of an edge, then there is the edge itself, and finally, at the highest level of organization, is the geometry or structure of the edge. This study used computer simulations to (1) find out whether effects of edge shapes on animal behavior can arise as emergent properties solely due to reactions to edges in general, without the animals reacting to the shapes of the edges, and to (2) generate predictions to allow field and experimental studies to test mechanisms of edge shape response. Individual animals were modeled traveling inside a habitat patch that had different kinds of edge shapes (convex, concave and straight). When animals responded edges of patches, this created an emergent property of responding to the shape of the edge. The response was mostly to absolute width of the shapes, and not the narrowness of them. When animals were attracted to edges, then they tended to collect in convexities and disperse from concavities, and the opposite happened when animals avoided edges. Most of the responses occurred within a distance of 40% of the perceptual range from the tip of the shapes. Predictions were produced for directionality at various locations and combinations of treatments, to be used for testing edge behavior mechanisms. These results suggest that edge shapes tend to either concentrate or disperse animals, simply because the animals are either attracted to or avoid edges, with an effect as great as 3 times the normal density. Thus edge shape could affect processes like pollination, seed predation and dispersal and predator abundance

    TRY plant trait database - enhanced coverage and open access

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    Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    The Formin-Homology Protein SmDia Interacts with the Src Kinase SmTK and the GTPase SmRho1 in the Gonads of Schistosoma mansoni

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    BACKGROUND:Schistosomiasis (bilharzia) is a parasitic disease of worldwide significance affecting human and animals. As schistosome eggs are responsible for pathogenesis, the understanding of processes controlling gonad development might open new perspectives for intervention. The Src-like tyrosine-kinase SmTK3 of Schistosoma mansoni is expressed in the gonads, and its pharmacological inhibition reduces mitogenic activity and egg production in paired females in vitro. Since Src kinases are important signal transduction proteins it is of interest to unravel the signaling cascades SmTK3 is involved in to understand its cellular role in the gonads. METHODOLOGY AND RESULTS:Towards this end we established and screened a yeast two-hybrid (Y2H) cDNA library of adult S. mansoni with a bait construct encoding the SH3 (src homology) domain and unique site of SmTK3. Among the binding partners found was a diaphanous homolog (SmDia), which was characterized further. SmDia is a single-copy gene transcribed throughout development with a bias towards male transcription. Its deduced amino acid sequence reveals all diaphanous-characteristic functional domains. Binding studies with truncated SmDia clones identified SmTK3 interaction sites demonstrating that maximal binding efficiency depends on the N-terminal part of the FH1 (formin homology) domain and the inter-domain region of SmDia located upstream of FH1 in combination with the unique site and the SH3 domain of SmTK3, respectively. SmDia also directly interacted with the GTPase SmRho1 of S. mansoni. In situ hybridization experiments finally demonstrated that SmDia, SmRho1, and SmTK3 are transcribed in the gonads of both genders. CONCLUSION:These data provide first evidence for the existence of two cooperating pathways involving Rho and Src that bridge at SmDia probably organizing cytoskeletal events in the reproductive organs of a parasite, and beyond that in gonads of eukaryotes. Furthermore, the FH1 and inter domain region of SmDia have been discovered as binding sites for the SH3 and unique site domains of SmTK3, respectively

    Generalised Anxiety Disorder – A Twin Study of Genetic Architecture, Genome-Wide Association and Differential Gene Expression

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    Generalised Anxiety Disorder (GAD) is a common anxiety-related diagnosis, affecting approximately 5% of the adult population. One characteristic of GAD is a high degree of anxiety sensitivity (AS), a personality trait which describes the fear of arousal-related sensations. Here we present a genome-wide association study of AS using a cohort of 730 MZ and DZ female twins. The GWAS showed a significant association for a variant within the RBFOX1 gene. A heritability analysis of the same cohort also confirmed a significant genetic component with h2 of 0.42. Additionally, a subset of the cohort (25 MZ twins discordant for AS) was studied for evidence of differential expression using RNA-seq data. Significant differential expression of two exons with the ITM2B gene within the discordant MZ subset was observed, a finding that was replicated in an independent cohort. While previous research has shown that anxiety has a high comorbidity with a variety of psychiatric and neurodegenerative disorders, our analysis suggests a novel etiology specific to AS

    Effect of Citalopram on Emotion Processing in Humans:A Combined 5-HT [C]CUMI-101 PET and Functional MRI Study

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    A subset of patients started on a selective serotonin reuptake inhibitor (SSRI) initially experience increased anxiety, which can lead to early discontinuation before therapeutic effects are manifest. The neural basis of this early SSRI effect is not known. Presynaptic dorsal raphe neuron (DRN) 5-HT1A receptors are known to play a critical role in affect processing. Thus we investigated the effect of acute citalopram on emotional processing and the relationship between DRN 5-HT1A receptor availability and amygdala reactivity. Thirteen (mean age 48±9 years) healthy male subjects received either a saline or citalopram infusion intravenously (10 mg over 30 min) on separate occasions in a single-blind, random order, cross-over design. On each occasion, participants underwent a block design face-emotion processing task during fMRI known to activate the amygdala. Ten subjects also completed a positron emission tomography (PET) scan to quantify DRN 5-HT1A availability using [(11)C]CUMI-101.Citalopram infusion when compared to saline resulted in a significantly increased bilateral amygdala responses to fearful vs. neutral faces (Left p=0.025; Right p=0.038 FWE-corrected). DRN [(11)C]CUMI-101availability significantly positively correlated with the effect of citalopram on the left amygdala response to fearful faces (Z=2.51, p=0.027) and right amygdala response to happy faces (Z=2.33, p=0.032). Our findings indicate that the initial effect of SSRI treatment is to alter processing of aversive stimuli, and that this is linked to DRN 5-HT1A receptors in line with evidence that 5-HT1A receptors have a role in mediating emotional processing

    The Action Mechanism of the Myc Inhibitor Termed Omomyc May Give Clues on How to Target Myc for Cancer Therapy

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    Recent evidence points to Myc – a multifaceted bHLHZip transcription factor deregulated in the majority of human cancers – as a priority target for therapy. How to target Myc is less clear, given its involvement in a variety of key functions in healthy cells. Here we report on the action mechanism of the Myc interfering molecule termed Omomyc, which demonstrated astounding therapeutic efficacy in transgenic mouse cancer models in vivo. Omomyc action is different from the one that can be obtained by gene knockout or RNA interference, approaches designed to block all functions of a gene product. This molecule – instead – appears to cause an edge-specific perturbation that destroys some protein interactions of the Myc node and keeps others intact, with the result of reshaping the Myc transcriptome. Omomyc selectively targets Myc protein interactions: it binds c- and N-Myc, Max and Miz-1, but does not bind Mad or select HLH proteins. Specifically, it prevents Myc binding to promoter E-boxes and transactivation of target genes while retaining Miz-1 dependent binding to promoters and transrepression. This is accompanied by broad epigenetic changes such as decreased acetylation and increased methylation at H3 lysine 9. In the presence of Omomyc, the Myc interactome is channeled to repression and its activity appears to switch from a pro-oncogenic to a tumor suppressive one. Given the extraordinary therapeutic impact of Omomyc in animal models, these data suggest that successfully targeting Myc for cancer therapy might require a similar twofold action, in order to prevent Myc/Max binding to E-boxes and, at the same time, keep repressing genes that would be repressed by Myc

    Maize Inbreds Exhibit High Levels of Copy Number Variation (CNV) and Presence/Absence Variation (PAV) in Genome Content

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    Following the domestication of maize over the past ∼10,000 years, breeders have exploited the extensive genetic diversity of this species to mold its phenotype to meet human needs. The extent of structural variation, including copy number variation (CNV) and presence/absence variation (PAV), which are thought to contribute to the extraordinary phenotypic diversity and plasticity of this important crop, have not been elucidated. Whole-genome, array-based, comparative genomic hybridization (CGH) revealed a level of structural diversity between the inbred lines B73 and Mo17 that is unprecedented among higher eukaryotes. A detailed analysis of altered segments of DNA conservatively estimates that there are several hundred CNV sequences among the two genotypes, as well as several thousand PAV sequences that are present in B73 but not Mo17. Haplotype-specific PAVs contain hundreds of single-copy, expressed genes that may contribute to heterosis and to the extraordinary phenotypic diversity of this important crop
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