60 research outputs found
Somato-dendritic vasopressin and oxytocin secretion in endocrine and autonomic regulation
Somatoâdendritic secretion was first demonstrated over 30 years ago. However, although its existence has become widely accepted, the function of somatoâdendritic secretion is still not completely understood. Hypothalamic magnocellular neurosecretory cells were among the first neuronal phenotypes in which somatoâdendritic secretion was demonstrated and are among the neurones for which the functions of somatoâdendritic secretion are best characterised. These neurones secrete the neuropeptides, vasopressin and oxytocin, in an orthograde manner from their axons in the posterior pituitary gland into the blood circulation to regulate body fluid balance and reproductive physiology. Retrograde somatoâdendritic secretion of vasopressin and oxytocin modulates the activity of the neurones from which they are secreted, as well as the activity of neighbouring populations of neurones, to provide intraâ and interâpopulation signals that coordinate the endocrine and autonomic responses for the control of peripheral physiology. Somatoâdendritic vasopressin and oxytocin have also been proposed to act as hormoneâlike signals in the brain. There is some evidence that somatoâdendritic secretion from magnocellular neurosecretory cells modulates the activity of neurones beyond their local environment where there are no vasopressinâ or oxytocinâcontaining axons but, to date, there is no conclusive evidence for, or against, hormoneâlike signalling throughout the brain, although it is difficult to imagine that the levels of vasopressin found throughout the brain could be underpinned by release from relatively sparse axon terminal fields. The generation of data to resolve this issue remains a priority for the field.http://wileyonlinelibrary.com/journal/jne2021-04-17hj2020Immunolog
Optimizing the growth conditions of Al mirrors for superconducting nanowire single-photon detectors
We investigate the growth conditions for thin (less than 200 nm) sputtered
aluminum (Al) films. These coatings are needed for various applications, e.g.
for advanced manufacturing processes in the aerospace industry or for
nanostructures for quantum devices. Obtaining high-quality films, with low
roughness, requires precise optimization of the deposition process. To this
end, we tune various sputtering parameters such as the deposition rate,
temperature, and power, which enables 50 nm thin films with a root mean square
(RMS) roughness of less than 1 nm and high reflectivity. Finally, we confirm
the high quality of the deposited films by realizing superconducting
single-photon detectors integrated into multi-layer heterostructures consisting
of an aluminum mirror and a silicon dioxide dielectric spacer. We achieve an
improvement in detection efficiency at 780 nm from 40 % to 70 % by this
integration approach.Comment: 11 pages, 6 figure
Scaling behavior of the spin pumping effect in ferromagnet/platinum bilayers
We systematically measured the DC voltage V_ISH induced by spin pumping
together with the inverse spin Hall effect in ferromagnet/platinum bilayer
films. In all our samples, comprising ferromagnetic 3d transition metals,
Heusler compounds, ferrite spinel oxides, and magnetic semiconductors, V_ISH
invariably has the same polarity. V_ISH furthermore scales with the
magnetization precession cone angle with a universal prefactor, irrespective of
the magnetic properties, the charge carrier transport mechanism or type. These
findings quantitatively corroborate the present theoretical understanding of
spin pumping in combination with the inverse spin Hall effect
Scaling behavior of the spin pumping effect in ferromagnet/platinum bilayers
We systematically measured the DC voltage V_ISH induced by spin pumping
together with the inverse spin Hall effect in ferromagnet/platinum bilayer
films. In all our samples, comprising ferromagnetic 3d transition metals,
Heusler compounds, ferrite spinel oxides, and magnetic semiconductors, V_ISH
invariably has the same polarity. V_ISH furthermore scales with the
magnetization precession cone angle with a universal prefactor, irrespective of
the magnetic properties, the charge carrier transport mechanism or type. These
findings quantitatively corroborate the present theoretical understanding of
spin pumping in combination with the inverse spin Hall effect
Towards Oxide Electronics:a Roadmap
At the end of a rush lasting over half a century, in which CMOS technology has been experiencing a constant and breathtaking increase of device speed and density, Moore's law is approaching the insurmountable barrier given by the ultimate atomic nature of matter. A major challenge for 21st century scientists is finding novel strategies, concepts and materials for replacing silicon-based CMOS semiconductor technologies and guaranteeing a continued and steady technological progress in next decades. Among the materials classes candidate to contribute to this momentous challenge, oxide films and heterostructures are a particularly appealing hunting ground. The vastity, intended in pure chemical terms, of this class of compounds, the complexity of their correlated behaviour, and the wealth of functional properties they display, has already made these systems the subject of choice, worldwide, of a strongly networked, dynamic and interdisciplinary research community. Oxide science and technology has been the target of a wide four-year project, named Towards Oxide-Based Electronics (TO-BE), that has been recently running in Europe and has involved as participants several hundred scientists from 29 EU countries. In this review and perspective paper, published as a final deliverable of the TO-BE Action, the opportunities of oxides as future electronic materials for Information and Communication Technologies ICT and Energy are discussed. The paper is organized as a set of contributions, all selected and ordered as individual building blocks of a wider general scheme. After a brief preface by the editors and an introductory contribution, two sections follow. The first is mainly devoted to providing a perspective on the latest theoretical and experimental methods that are employed to investigate oxides and to produce oxide-based films, heterostructures and devices. In the second, all contributions are dedicated to different specific fields of applications of oxide thin films and heterostructures, in sectors as data storage and computing, optics and plasmonics, magnonics, energy conversion and harvesting, and power electronics
Spin Hall magnetoresistance in a canted ferrimagnet
We study the spin Hall magnetoresistance effect in ferrimagnet/normal metal bilayers, comparing the response in collinear and canted magnetic phases. In the collinear magnetic phase, in which the sublattice magnetic moments are all aligned along the same axis, we observe the conventional spin Hall magnetoresistance. In contrast, in the canted phase, the magnetoresistance changes sign. Using atomistic spin simulations and x-ray absorption experiments, we can understand these observations in terms of the magnetic field and temperature dependent orientation of magnetic moments on different magnetic sublattices. This enables a magnetotransport based investigation of noncollinear magnetic textures
Structural constraints revealed in consistent nucleosome positions in the genome of S. cerevisiae
<p>Abstract</p> <p>Background</p> <p>Recent advances in the field of high-throughput genomics have rendered possible the performance of genome-scale studies to define the nucleosomal landscapes of eukaryote genomes. Such analyses are aimed towards providing a better understanding of the process of nucleosome positioning, for which several models have been suggested. Nevertheless, questions regarding the sequence constraints of nucleosomal DNA and how they may have been shaped through evolution remain open. In this paper, we analyze in detail different experimental nucleosome datasets with the aim of providing a hypothesis for the emergence of nucleosome-forming sequences.</p> <p>Results</p> <p>We compared the complete sets of nucleosome positions for the budding yeast (<it>Saccharomyces cerevisiae</it>) as defined in the output of two independent experiments with the use of two different experimental techniques. We found that < 10% of the experimentally defined nucleosome positions were consistently positioned in both datasets. This subset of well-positioned nucleosomes, when compared with the bulk, was shown to have particular properties at both sequence and structural levels. Consistently positioned nucleosomes were also shown to occur preferentially in pairs of dinucleosomes, and to be surprisingly less conserved compared with their adjacent nucleosome-free linkers.</p> <p>Conclusion</p> <p>Our findings may be combined into a hypothesis for the emergence of a weak nucleosome-positioning code. According to this hypothesis, consistent nucleosomes may be partly guided by nearby nucleosome-free regions through statistical positioning. Once established, a set of well-positioned consistent nucleosomes may impose secondary constraints that further shape the structure of the underlying DNA. We were able to capture these constraints through the application of a recently introduced structural property that is related to the symmetry of DNA curvature. Furthermore, we found that both consistently positioned nucleosomes and their adjacent nucleosome-free regions show an increased tendency towards conservation of this structural feature.</p
Epigenetic and transcriptional signatures of stable versus plastic differentiation of proinflammatory gd T cell subsets
Two distinct subsets of γΎ T cells that produce interleukin 17 (IL-17) (CD27(-) γΎ T cells) or interferon-γ (IFN-γ) (CD27(+) γΎ T cells) develop in the mouse thymus, but the molecular determinants of their functional potential in the periphery remain unknown. Here we conducted a genome-wide characterization of the methylation patterns of histone H3, along with analysis of mRNA encoding transcription factors, to identify the regulatory networks of peripheral IFN-γ-producing or IL-17-producing γΎ T cell subsets in vivo. We found that CD27(+) γΎ T cells were committed to the expression of Ifng but not Il17, whereas CD27(-) γΎ T cells displayed permissive chromatin configurations at loci encoding both cytokines and their regulatory transcription factors and differentiated into cells that produced both IL-17 and IFN-γ in a tumor microenvironment
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