UAV Control in Close Proximities - Ceiling Effect on Battery Lifetime

With the recent developments in the unmanned aerial vehicles (UAV), it is expected them to interact and collaborate with their surrounding objects, other robots and people in order to wisely plan and execute particular tasks. Although these interaction operations are inherently challenging as compared to free-flight missions, they might bring diverse advantages. One of them is their basic aerodynamic interaction during the flight in close proximities which can result in a reduction of the controller effort. In this study, by collecting real-time data, we have observed that the current drawn by the battery can be decreased while flying very close to the surroundings with the help of the ceiling effect. For the first time, this phenomenon is analyzed in terms of battery lifetime degradation by using a simple full equivalent cycle counting method. Results show that cycling related effect on battery degradation can be reduced by a 15.77% if the UAV can utilize ceiling effect.Comment: ICoIAS 201

Self-Domain Adaptation for Face Anti-Spoofing

Although current face anti-spoofing methods achieve promising results under intra-dataset testing, they suffer from poor generalization to unseen attacks. Most existing works adopt domain adaptation (DA) or domain generalization (DG) techniques to address this problem. However, the target domain is often unknown during training which limits the utilization of DA methods. DG methods can conquer this by learning domain invariant features without seeing any target data. However, they fail in utilizing the information of target data. In this paper, we propose a self-domain adaptation framework to leverage the unlabeled test domain data at inference. Specifically, a domain adaptor is designed to adapt the model for test domain. In order to learn a better adaptor, a meta-learning based adaptor learning algorithm is proposed using the data of multiple source domains at the training step. At test time, the adaptor is updated using only the test domain data according to the proposed unsupervised adaptor loss to further improve the performance. Extensive experiments on four public datasets validate the effectiveness of the proposed method.Comment: Camera Ready, AAAI 202

Assembly of Silver Nanoparticles into Hollow Spheres Using Eu(III) Compound based on Trifluorothenoyl-Acetone

The preparation of luminescent silver hollow spheres using Eu(III) compound based on trifluorothenoyl-acetone is described. The structure and size of silver hollow spheres were determined by TEM images. The result shows the formation of hollow structure and average size of the silver hollow spheres (0.9 μm). The silver hollow spheres were further characterized by UV absorption spectrum, SNOM and SEM images, suggesting them to be formed by self-assemble of some isolated silver nanoparticles. The luminescent properties of them were also investigated and they are shown to be high emission strength; moreover, they offer the distinct advantage of a lower packing density compared with other commercial luminescent products

A Demographic Profile of Independently Incorporated Native American Foundations and Selected Funds in the United States

This report gives basic demographic information on 60 grantmaking entities grouped into three categories: 1) Native foundations that are independently incorporated; 2) 501c3 Native organizations; and 3) tribal funds. These categories capture the variety of Native controlled approaches currently at work in the field

Anxiety Specific Response and Contribution of Active Hippocampal Neural Stem Cells to Chronic Pain Through Wnt/β-Catenin Signaling in Mice

Chronic pain usually results in persistent anxiety, which worsens the life quality of patients and complicates the treatment of pain. Hippocampus is one of the few brain regions in many mammalians species which harbors adult neural stem cells (NSCs), and plays a key role in the development and maintenance of chronic anxiety. Recent studies have suggested a potential involvement of hippocampal neurogenesis in modulating chronic pain. Whether and how hippocampal NSCs are involved in the pain-associated anxiety remains unclear. Here, we report that mice suffering persistent neuropathic pain showed a quick reduction of active NSCs in the ventral dentate gyrus (vDG), which was followed by the decrease of neurogenesis and appearance of anxiety. Wnt/β-catenin signaling, a key pathway in sustaining the active status of NSCs was suppressed in the vDG of mice suffering chronic pain. Depleting β-catenin by inducible Nestin-Cre significantly reduced the number of active NSCs and facilitated anxiety development, while expressing stabilized β-catenin amplified active NSCs and alleviated anxiety, indicating that Wnt activated NSCs is required for anxiety development under chronic pain. Treatment with Fluoxetine, the most widely used anxiolytic in clinic, significantly increased the proliferation of active NSCs and enhanced Wnt signaling. Interestingly, both β-catenin manipulation and Fluoxetine treatment had no significant effects on the pain thresholds. Therefore, our data demonstrated an anxiety-specific response and contribution of activated NSCs to chronic pain through Wnt/β-catenin signaling, which may be targeted for treating chronic pain- or other diseases-associated anxiety

In Situ Synthesis of Reduced Graphene Oxide-Reinforced Silicone-Acrylate Resin Composite Films Applied in Erosion Resistance

The reduced graphene oxide reinforced silicone-acrylate resin composite films (rGO/SAR composite films) were prepared by in situ synthesis method. The structure of rGO/SAR composite films was characterized by Raman spectrum, atomic force microscope, scanning electron microscopy, and thermogravimetric analyzer. The results showed that the rGO were uniformly dispersed in silicone-acrylate resin matrix. Furthermore, the effect of rGO loading on mechanical properties of composite films was investigated by bulge test. A significant enhancement (ca. 290% and 320%) in Young’s modulus and yield stress was obtained by adding the rGO to silicone-acrylate resin. At the same time, the adhesive energy between the composite films and metal substrate was also improved to be about 200%. Moreover, the erosion resistance of the composite films was also investigated as function of rGO loading. The rGO had great effect on the erosion resistance of the composite films, in which the Rcorr (ca. 0.8 mm/year) of composite film was far lower than that (28.7 mm/year) of pure silicone-acrylate resin film. Thus, this approach provides a novel route to investigate mechanical stability of polymer composite films and improve erosion resistance of polymer coating, which are very important to be used in mechanical-corrosion coupling environments

Intermolecular Failure of L-type Ca(2+) Channel and Ryanodine Receptor Signaling in Hypertrophy

Pressure overload–induced hypertrophy is a key step leading to heart failure. The Ca(2+)-induced Ca(2+) release (CICR) process that governs cardiac contractility is defective in hypertrophy/heart failure, but the molecular mechanisms remain elusive. To examine the intermolecular aspects of CICR during hypertrophy, we utilized loose-patch confocal imaging to visualize the signaling between a single L-type Ca(2+) channel (LCC) and ryanodine receptors (RyRs) in aortic stenosis rat models of compensated (CHT) and decompensated (DHT) hypertrophy. We found that the LCC-RyR intermolecular coupling showed a 49% prolongation in coupling latency, a 47% decrease in chance of hit, and a 72% increase in chance of miss in DHT, demonstrating a state of “intermolecular failure.” Unexpectedly, these modifications also occurred robustly in CHT due at least partially to decreased expression of junctophilin, indicating that intermolecular failure occurs prior to cellular manifestations. As a result, cell-wide Ca(2+) release, visualized as “Ca(2+) spikes,” became desynchronized, which contrasted sharply with unaltered spike integrals and whole-cell Ca(2+) transients in CHT. These data suggested that, within a certain limit, termed the “stability margin,” mild intermolecular failure does not damage the cellular integrity of excitation-contraction coupling. Only when the modification steps beyond the stability margin does global failure occur. The discovery of “hidden” intermolecular failure in CHT has important clinical implications

Revealing the activity of Co3Mo3N and Co3Mo3N0.5 as electrocatalysts for the hydrogen evolution reaction

The hydrogen evolution reaction (HER) from water is governed by electrocatalysts used. Multiple factors such as crystal structure, composition and morphology dictate the final catalytic performance. However, as multicomponent materials are developed to replace noble metals in the HER, it has become increasingly difficult to identify intrinsically active materials. Hence, there is an imperative for phase-pure catalysts to be synthetized and tested without obscuring contributions from impurities or substrates. Herein, we demonstrate that phase-pure, unsupported Co3Mo3N achieves a competitively low overpotential (OVP) of 108 ± 8 mV at 10 mA cm‒2 in 0.5 M H2SO4. Density functional theory (DFT) reveals weakly binding metal sites as the catalytic centres for the HER in the nitride. Remarkably, the N-deficient Co3Mo3N0.5 shows similar electrochemical properties but has limited chemical stability under cathodic bias. Thus, even though nitrogen sites play only a minor role in catalytic performance, their occupancy is crucial for the stability of nitride catalysts in the corrosive electrolyte. The composite of Co3Mo3N on Ni-foam sustains 10 ± 0.7 mA cm‒2 at applied potential of just 20 mV over extended time, highlighting the utility of nitrides for future design of stable and active HER catalytic systems

Glycolysis mediates neuron specific histone acetylation in valproic acid-induced human excitatory neuron differentiation

Pregnancy exposure of valproic acid (VPA) is widely adopted as a model of environmental factor induced autism spectrum disorder (ASD). Increase of excitatory/inhibitory synaptic transmission ratio has been proposed as the mechanism of VPA induced ASD. How this happened, particularly at the level of excitatory neuron differentiation in human neural progenitor cells (NPCs) remains largely unclear. Here, we report that VPA exposure remarkably inhibited human NPC proliferation and induced excitatory neuronal differentiation without affecting inhibitory neurons. Following VPA treatment, mitochondrial dysfunction was observed before neuronal differentiation, as showed by ultrastructural changes, respiratory complex activity, mitochondrial membrane potential and oxidation levels. Meanwhile, extracellular acidification assay revealed an elevation of glycolysis by VPA stimulation. Interestingly, inhibiting glycolysis by 2-deoxy-d-glucose-6-phosphate (2-DG) efficiently blocked the excitatory neuronal differentiation of human NPCs induced by VPA. Furthermore, 2-DG treatment significantly compromised the VPA-induced expression of H3ac and H3K9ac, and the VPA-induced binding of H3K9ac on the promoter of Ngn2 and Mash1, two key transcription factors of excitatory neuron fate determination. These data, for the first time, demonstrated that VPA biased excitatory neuron differentiation by glycolysis-mediated histone acetylation of neuron specific transcription factors

Design and test of powerful air-assisted sprayer for high stalk crops

The canopies of high stalk crops, such as maize, intersect the rows at the later stages of growth, making conventional sprayers unable to enter the field for spraying. Air-assisted sprayers are often used to improve the deposition of droplets inside the canopy. In this study, the sprayer structure, the air-assisted system, and the spraying system were designed. The air-assisted conveyor system characteristics were numerically analyzed, and the wind-field distribution was tested. The wind-field distribution results showed that the near-ground wind speed exceeded 5 m s-1 in the sampling interval from 10 to 35 metres. The wind field covered a concentrated spatial area with a downward pressure trend, resulting in better drift resistance and penetration. Field tests for droplet distribution were conducted at three maize heights to verify the powerful air-assisted sprayer's technical performance and working quality. The test results showed that the droplet deposition and coverage decreased gradually along the range direction, and the top layer had the highest deposition and coverage across the canopy. The upper canopy of 0 to 12 metres range demonstrated a greater extent of coverage and deposition. The peak deposition area expanded from 9 to 33 metres in the lower canopy, with an average value of 3.77 μg cm-2. The droplet coverage within the 30 to 60 metres range only amounted to 15% to 18% of the total coverage