3,767 research outputs found
SAWU-Net: Spatial Attention Weighted Unmixing Network for Hyperspectral Images
Hyperspectral unmixing is a critical yet challenging task in hyperspectral
image interpretation. Recently, great efforts have been made to solve the
hyperspectral unmixing task via deep autoencoders. However, existing networks
mainly focus on extracting spectral features from mixed pixels, and the
employment of spatial feature prior knowledge is still insufficient. To this
end, we put forward a spatial attention weighted unmixing network, dubbed as
SAWU-Net, which learns a spatial attention network and a weighted unmixing
network in an end-to-end manner for better spatial feature exploitation. In
particular, we design a spatial attention module, which consists of a pixel
attention block and a window attention block to efficiently model pixel-based
spectral information and patch-based spatial information, respectively. While
in the weighted unmixing framework, the central pixel abundance is dynamically
weighted by the coarse-grained abundances of surrounding pixels. In addition,
SAWU-Net generates dynamically adaptive spatial weights through the spatial
attention mechanism, so as to dynamically integrate surrounding pixels more
effectively. Experimental results on real and synthetic datasets demonstrate
the better accuracy and superiority of SAWU-Net, which reflects the
effectiveness of the proposed spatial attention mechanism.Comment: IEEE GRSL 202
Superfolded configuration induced low thermal conductivity in two-dimensional carbon allotropes revealed via machine learning force constant potential
Understanding the fundamental link between structure and functionalization is
crucial for the design and optimization of functional materials, since
different structural configurations could trigger materials to demonstrate
diverse physical, chemical, and electronic properties. However, the correlation
between crystal structure and thermal conductivity (\k{appa}) remains
enigmatic. In this study, taking two-dimensional (2D) carbon allotropes as
study cases, we utilize phonon Boltzmann transport equation (BTE) along with
machine learning force constant potential to thoroughly explore the complex
folding structure of pure sp2 hybridized carbon materials from the perspective
of crystal structure, mode-level phonon resolved thermal transport, and atomic
interactions, with the goal of identifying the underlying relationship between
2D geometry and \k{appa}. We propose two potential structure evolution
mechanisms for targeted thermal transport properties: in-plane and out-of-plane
folding evolutions, which are generally applicable to 2D carbon allotropes. It
is revealed that the folded structure produces strong symmetry breaking, and
simultaneously produces exceptionally strongly suppressed phonon group
velocities, strong phonon-phonon scattering, and weak phonon hydrodynamics,
which ultimately lead to low \k{appa}. The insight into the folded effect of
atomic structures on thermal transport deepens our understanding of the
relationship between structure and functionalization, which offers
straightforward guidance for designing novel nanomaterials with targeted
\k{appa}, as well as propel developments in materials science and engineering
A broad-spectrum substrate for the human UDP-glucuronosyltransferases and its use for investigating glucuronidation inhibitors
Strong inhibition of the human UDP-glucuronosyltransferase enzymes (UGTs) may lead to undesirable effects, including hyperbilirubinaemia and drugiherb-drug interactions. Currently, there is no good way to examine the inhibitory effects and specificities of compounds toward all the important human UGTs, side-by-side and under identical conditions. Herein, we report a new, broad-spectrum substrate for human UGTs and its uses in screening and characterizing of UGT inhibitors. Following screening a variety of phenolic compound(s), we have found that methylophiopogonanone A (MOA) can be readily O-glucuronidated by all tested human UGTs, including the typical N-glucuronidating enzymes UGT1A4 and UGT2B10. MOA-O-glucuronidation yielded a single mono-O-glucuronide that was biosynthesized and purified for structural characterization and for constructing an LC-UV based MOA-O-glucuronidation activity assay, which was then used for investigating MOA-O-glucuronidation kinetics in recombinant human UGTs. The derived K-m values were crucial for selecting the most suitable assay conditions for assessing inhibitory potentials and specificity of test compound(s). Furthermore, the inhibitory effects and specificities of four known UGT inhibitors were reinvestigated by using MOA as the substrate for all tested UGTs. Collectively, MOA is a broad-spectrum substrate for the human UGTs, which offers a new and practical tool for assessing inhibitory effects and specificities of UGT inhibitors. (C) 2021 Elsevier B.V. All rights reserved.Peer reviewe
Quantum LiDAR with Frequency Modulated Continuous Wave
The range and speed of a moving object can be ascertained using the sensing
technique known as light detection and ranging (LiDAR). It has recently been
suggested that quantum LiDAR, which uses entangled states of light, can enhance
the capabilities of LiDAR. Entangled pulsed light is used in prior quantum
LiDAR approaches to assess both range and velocity at the same time using the
pulses' time of flight and Doppler shift. The entangled pulsed light generation
and detection, which are crucial for pulsed quantum LiDAR, are often
inefficient. Here, we study a quantum LiDAR that operates on a
frequency-modulated continuous wave (FMCW), as opposed to pulses. We first
outline the design of the quantum FMCW LiDAR using entangled
frequency-modulated photons in a Mach-Zehnder interferometer, and we
demonstrate how it can increase accuracy and resolution for range and velocity
measurements by and , respectively, with entangled photons.
We also demonstrate that quantum FMCW LiDAR may perform simultaneous
measurements of the range and velocity without the need for quantum pulsed
compression, which is necessary in pulsed quantum LiDAR. Since the generation
of entangled photons is the only inefficient nonlinear optical process needed,
the quantum FMCW LiDAR is better suited for practical implementations.
Additionally, most measurements in the quantum FMCW LiDAR can be carried out
electronically by down-converting optical signal to microwave region
Dl-3-n-butylphthalide attenuates cerebral ischemia/reperfusion injury in mice through AMPK-mediated mitochondrial fusion
Introduction: NBP is a compound isolated from celery seeds, which was approved by the National Medical Products Administration in 2002 for clinical treatment of ischemic stroke. However, in brain ischemia/reperfusion (I/R) injury, the related research on mitochondrial dynamics and its mechanism of action of NBP still need to be further studied. The aim of this study was to assess NBP on cerebral pathology in ischemic stroke in vivo, with a specific focus on the molecular mechanisms of how NBP promotes mitochondrial fusion.Methods: Male C57BL/6 mice were utilized in this study and were subjected to middle cerebral artery occlusion/reperfusion (MCAO/R). Pre-ischemia, NBP was administered through intraperitoneal (i.p.) injection for 7 days.Results: Our findings demonstrated that NBP effectively reduced infarct volume, improved neurological dysfunction, enhanced cerebral blood flow, and promoted mitochondrial fusion in mice subjected to MCAO/R. More importantly, the pro-fusion effects of NBP were found to be linked to the activation of AMPK/Mfn1 pathway, and with the activation of neurological function, which was partially eliminated by inhibitors of AMPK.Discussion: Our results revealed that NBP is a novel mitochondrial fusion promoter in protecting against ischemic stroke through the AMPK-mediated Mfn1. These findings contribute to the understanding of novel mechanisms involved in the protection of neurological function following NBP treatment for ischemic stroke
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Nitrogen availability prevents oxidative effects of salinity on wheat growth and photosynthesis by up-regulating the antioxidants and osmolytes metabolism, and secondary metabolite accumulation.
Funder: NorthWest A&F University Yaangling, Shaanxi, China.BACKGROUND: Salinity is one of the damaging abiotic stress factor. Proper management techniques have been proposed to considerably lower the intensity of salinity on crop growth and productivity. Therefore experiments were conducted to assess the role of improved nitrogen (N) supplementation on the growth and salinity stress tolerance in wheat by analyzing the antioxidants, osmolytes and secondary metabolites. RESULTS: Salinity (100 mM NaCl) stress imparted deleterious effects on the chlorophyll and carotenoid synthesis as well as the photosynthetic efficiency. N supplementation resulted in increased photosynthetic rate, stomatal conductance and internal CO2 concentration with effects being much obvious in seedlings treated with higher N dose. Under non-saline conditions at both N levels, protease and lipoxygenase activity reduced significantly reflecting in reduced oxidative damage. Such effects were accompanied by reduced generation of toxic radicals like hydrogen peroxide and superoxide, and lipid peroxidation in N supplemented seedlings. Antioxidant defence system was up-regulated under saline and non-saline growth conditions due to N supplementation leading to protection of major cellular processes like photosynthesis, membrane structure and function, and mineral assimilation. Increased osmolyte and secondary metabolite accumulation, and redox components in N supplemented plants regulated the ROS metabolism and NaCl tolerance by further strengthening the antioxidant mechanisms. CONCLUSIONS: Findings of present study suggest that N availability regulated the salinity tolerance by reducing Na uptake and strengthening the key tolerance mechanisms
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