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2D Derivative Phase Induced Growth of 3D All Inorganic Perovskite Micro–Nanowire Array Based Photodetectors
Get PDFA large number of derivative phases in inorganic perovskites are reported with special structures and extraordinary performances in photoelectronic device applications. The reverse phase transition between derivative phases and perovskites usually induces recrystallization or forms mixed components. In this work, derivative phase‐induced growth of the CsPbBr₃ micro–nanowire (MW) array by utilizing phase transition of the 2D CsPb₂Br₅ phase is reported. Owing to its layered structure and phase transition, annealing of CsPb₂Br₅ at a temperature of 550℃ combined with solvent quenching leads to a templating effect to form a high‐quality CsBr MW array. Subsequent PbBr₂ deposition and the second annealing are employed to form aligned CsPbBr₃ MW arrays. Based on this method, a CsPbBr₃ MW array‐based photodetector is fabricated. The large grain size, less grain boundaries, and lower surface potential of the CsPbBr₃ MW array lead to high device performance with a responsivity of 7.66 A W⁻¹, a detectivity of ≈10¹² Jones, and long‐term operational stability over 1900 min.journal articl
Perturbative expansions of Rényi relative divergences and holography
Get PDFIn this paper, we develop a novel way to perturbatively calculate R´enyi relative divergences Dγ(ρ||σ) = trργσ1−γ and related quantities without using replica trick as well as analytic continuation. We explicitly determine the form of the perturbative term at any order by an integral along the modular flow of the unperturbed state. By applying the prescription to a class of reduced density matrices in conformal field theory, we find that the second order term of certain linear combination of the divergences has a holographic expression in terms of bulk symplectic form, which is a one parameter generalization of the statement “Fisher information = Bulk canonical energy”.journal articl
An optimal Sobolev embedding for L1
Get PDFIn this paper we establish an optimal Lorentz space estimate for the Riesz potential acting on curl-free vectors: There is a constant C = C(α,d) > 0 such that [Formula: see text] for all fields F ∈ L1(Rd;Rd) such that curl F = 0 in the sense of distributions. This is the best possible estimate on this scale of spaces and completes the picture in the regime p = 1 of the well-established results for p > 1.journal articl
Comparative analysis of worker head anatomy of Formica and Brachyponera (Hymenoptera: Formicidae)
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An Integrated Index: Engrams, Place Cells, and Hippocampal Memory
Get PDFThe hippocampus and its extended network contribute to encoding and recall of episodic experiences. Drawing from recent anatomical, physiological, and behavioral studies, we propose that hippocampal engrams function as indices to mediate memory recall. We broaden this idea to discuss potential relationships between engrams and hippocampal place cells, as well as the molecular, cellular, physiological, and circuit determinants of engrams that permit flexible routing of information to intra- and extrahippocampal circuits for reinstatement, a feature critical to memory indexing. Incorporating indexing into frameworks of memory function opens new avenues of study and even therapies for hippocampal dysfunction.journal articl
Climate change considerations are fundamental to management of deep‐sea resource extraction
Get PDFClimate change manifestation in the ocean, through warming, oxygen loss, increasing acidification, and changing particulate organic carbon flux (one metric of altered food supply), is projected to affect most deep-ocean ecosystems concomitantly with increasing direct human disturbance. Climate drivers will alter deep-sea biodiversity and associated ecosystem services, and may interact with disturbance from resource extraction activities or even climate geoengineering. We suggest that to ensure the effective management of increasing use of the deep ocean (e.g., for bottom fishing, oil and gas extraction, and deep-seabed mining), environmental management and developing regulations must consider climate change. Strategic planning, impact assessment and monitoring, spatial management, application of the precautionary approach, and full-cost accounting of extraction activities should embrace climate consciousness. Coupled climate and biological modeling approaches applied in the water and on the seafloor can help accomplish this goal. For example, Earth-System Model projections of climate-change parameters at the seafloor reveal heterogeneity in projected climate hazard and time of emergence (beyond natural variability) in regions targeted for deep-seabed mining. Models that combine climate-induced changes in ocean circulation with particle tracking predict altered transport of early life stages (larvae) under climate change. Habitat suitability models can help assess the consequences of altered larval dispersal, predict climate refugia, and identify vulnerable regions for multiple species under climate change. Engaging the deep observing community can support the necessary data provisioning to mainstream climate into the development of environmental management plans. To illustrate this approach, we focus on deep-seabed mining and the International Seabed Authority, whose mandates include regulation of all mineral-related activities in international waters and protecting the marine environment from the harmful effects of mining. However, achieving deep-ocean sustainability under the UN Sustainable Development Goals will require integration of climate consideration across all policy sectors.journal articl
Anterograde Axonal Transport in Neuronal Homeostasis and Disease
Get PDFNeurons are highly polarized cells with an elongated axon that extends far away from the cell body. To maintain their homeostasis, neurons rely extensively on axonal transport of membranous organelles and other molecular complexes. Axonal transport allows for spatio-temporal activation and modulation of numerous molecular cascades, thus playing a central role in the establishment of neuronal polarity, axonal growth and stabilization, and synapses formation. Anterograde and retrograde axonal transport are supported by various molecular motors, such as kinesins and dynein, and a complex microtubule network. In this review article, we will primarily discuss the molecular mechanisms underlying anterograde axonal transport and its role in neuronal development and maturation,including the establishment of functional synaptic connections.We will then provide an overview of the molecular and cellular perturbations that affect axonal transport and are often associated with axonal degeneration. Lastly, we will relate our current understanding of the role of axonal trafficking concerning anterograde trafficking of mRNA and its involvement in the maintenance of the axonal compartment and disease.journal articl
Prelimbic cortical targets of ventromedial thalamic projections include inhibitory interneurons and corticostriatal pyramidal neurons in the rat
Get PDFVentromedial thalamic axons innervate cortical layer I and make contacts onto the apical dendritic tuft of pyramidal neurons. Optical stimulation of ventromedial thalamic axon terminals in prefrontal cortical areas in mouse brain slices evokes responses in corticocortical, corticothalamic and layer I inhibitory interneurons. Using anterograde tracing techniques and immunohistochemistry in male Sprague–Dawley rats, we provide anatomical evidence that ventromedial thalamic axon terminals in prelimbic cortex make contacts onto pyramidal neurons and, in particular, onto corticostriatal neurons as well as layer I inhibitory interneurons. Using stereology, we made quantitative estimates of contacts in uppermost prelimbic layer I onto dendrites of pyramidal neurons, corticostriatal neurons and layer I inhibitory interneurons. Prefrontal cortex has long been associated with decision making. Specifically, corticostriatal neurons in rat prelimbic cortex play an important role in cost–benefit decision making. Although recent experiments have detailed the physiology of this area in thalamocortical circuits, the extent of the impact of ventromedial thalamic input on corticostriatal neurons or layer I inhibitory interneurons has not been explored. Our quantitative anatomical results provide evidence that most ventromedial thalamic input to pyramidal neurons is provided to corticostriatal neurons and that overall more contacts are made onto the population of excitatory than onto the population of inhibitory neurons.journal articl
Viscous flow through microfabricated axisymmetric contraction/expansion geometries
Get PDFWe employ a state-of-the-art microfabrication technique (selective laser-induced etching) to fabricate a set of axisymmetric microfluidic geometries featuring a 4:1 contraction followed by a 1:4 downstream expansion in the radial dimension. Three devices are fabricated: the first has a sudden contraction followed by a sudden expansion, the second features hyperbolic contraction and expansion profiles, and the third has a numerically optimized contraction/expansion profile intended to provide a constant extensional/compressional rate along the axis. We use micro-particle image velocimetry to study the creeping flow of a Newtonian fluid through the three devices and we compare the obtained velocity profiles with finite-volume numerical predictions, with good agreement. This work demonstrates the capability of this new microfabrication technique for producing accurate non-planar microfluidic geometries with complex shapes and with sufficient clarity for optical probes. The axisymmetric microfluidic geometries examined have potential to be used for the study of the extensional properties and non-linear dynamics of viscoelastic flows, and to investigate the transport and deformation dynamics of bubbles, drops, cells, and fibers.journal articl
Promoting Dual-Targeting Anticancer Effect by Regulating the Dynamic Intracellular Self-Assembly
Get PDFDespite the promise of nanomedicine in the fight against complex diseases, the enthusiasm for its pharmaceutical development is backed by the elevated costs associated with the R&D process. Therefore, as a compromise solution, nanotechnology was mainly applied as a drug delivery system to improve bioavailability and controllability of pharmaceutical drugs. Attempting to break the restrictions without elevating potential costs, we multiply the functions of excipients in the nanodelivery system by endowing subcellular-targeting ability. To prove the concept, fluorescent endoplasmic reticulum-targeted short peptides were covalently connected to chemotherapy medication chlorambucil achieving enhanced drug-loading efficiency. Via visualized intracellular dynamic enzyme-catalyzed hydrolysis, the ER-targeting excipient and nucleus-targeting chlorambucil are released simultaneously, achieving a synergistic anticancer effect and elucidating the influence of intracellular self-assembly transition on enzymatic reactions.journal articl