Spiking NeRF: Making Bio-inspired Neural Networks See through the Real World

Spiking neuron networks (SNNs) have been thriving on numerous tasks to leverage their promising energy efficiency and exploit their potentialities as biologically plausible intelligence. Meanwhile, the Neural Radiance Fields (NeRF) render high-quality 3D scenes with massive energy consumption, and few works delve into the energy-saving solution with a bio-inspired approach. In this paper, we propose spiking NeRF (SpikingNeRF), which aligns the radiance ray with the temporal dimension of SNN, to naturally accommodate the SNN to the reconstruction of Radiance Fields. Thus, the computation turns into a spike-based, multiplication-free manner, reducing the energy consumption. In SpikingNeRF, each sampled point on the ray is matched onto a particular time step, and represented in a hybrid manner where the voxel grids are maintained as well. Based on the voxel grids, sampled points are determined whether to be masked for better training and inference. However, this operation also incurs irregular temporal length. We propose the temporal condensing-and-padding (TCP) strategy to tackle the masked samples to maintain regular temporal length, i.e., regular tensors, for hardware-friendly computation. Extensive experiments on a variety of datasets demonstrate that our method reduces the $76.74\%$ energy consumption on average and obtains comparable synthesis quality with the ANN baseline

Maps of cropping patterns in China during 2015–2021

Multiple cropping is a widespread approach for intensifying crop production through rotations of diverse crops. Maps of cropping intensity with crop descriptions are important for supporting sustainable agricultural management. As the most populated country, China ranked first in global cereal production and the percentages of multiple-cropped land are twice of the global average. However, there are no reliable updated national-scale maps of cropping patterns in China. Here we present the first recent annual 500-m MODIS-based national maps of multiple cropping systems in China using phenologybased mapping algorithms with pixel purity-based thresholds, which provide information on cropping intensity with descriptions of three staple crops (maize, paddy rice, and wheat). The produced cropping patterns maps achieved an overall accuracy of 89% based on ground truth data, and a good agreement with the statistical data (R2 ≥ 0.89). The China Cropping Pattern maps (ChinaCP) are available for public download online. Cropping patterns maps in China and other countries with finer resolutions can be produced based on Sentinel-2 Multispectral Instrument (MSI) images using the shared code

In-depth understanding of the morphology effect of α-Fe2O3 on catalytic ethane destruction

Shape effects of nanocrystal catalysts in different reactions have attracted remarkable attention. In the present work, three types of α-Fe2O3 oxides with different micromorphologies were rationally synthesized via a facile solvothermal method and adopted in deep oxidation of ethane. The physicochemical properties of prepared materials were characterized by XRD, N2 sorption, FE-SEM, HR-TEM, FTIR, in situ DRIFTS, XPS, Mössbauer spectroscopy, in situ Raman, electron energy loss spectroscopy, and H2-TPR. Moreover, the formation energy of oxygen vacancy and surface electronic structure on various crystal faces of α-Fe2O3 were explored by DFT calculations. It is shown that nanosphere-like α-Fe2O3 exhibits much higher ethane destruction activity and reaction stability than nanocube-like α-Fe2O3 and nanorod-like α-Fe2O3 due to larger amounts of oxygen vacancies and lattice defects, which greatly enhance the concentration of reactive oxygen species, oxygen transfer speed, and material redox property. In addition to this, DFT results reveal that nanosphere-like α-Fe2O3 has the lowest formation energy of oxygen vacancy on the (110) facet (Evo (110) = 1.97 eV) and the strongest adsorption energy for ethane (−0.26 eV) and O2 (−1.58 eV), which can accelerate the ethane oxidation process. This study has deepened the understanding of the face-dependent activities of α-Fe2O3 in alkane destruction

Atomic-scale insights into the low-temperature oxidation of methanol over a single-atom Pt1-Co3O4 catalyst

Heterogeneous catalysts with single‐atom active sites offer a means of expanding the industrial application of noble metal catalysts. Herein, an atomically dispersed Pt1‐Co3O4 catalyst is presented, which exhibits an exceptionally high efficiency for the total oxidation of methanol. Experimental and theoretical investigations indicate that this catalyst consists of Pt sites with a large proportion of occupied high electronic states. These sites possess a strong affinity for inactive Co2+ sites and anchor over the surface of (111) crystal plane, which increases the metal–support interaction of the Pt1‐Co3O4 material and accelerates the rate of oxygen vacancies regeneration. In turn, this is determined to promote the coadsorption of the probe methanol molecule and O2. Density functional theory calculations confirm that the electron transfer over the oxygen vacancies reduces both the methanol adsorption energy and activation barriers for methanol oxidation, which is proposed to significantly enhance the dissociation of the CH bond in the methanol decomposition reaction. This investigation serves as a solid foundation for characterizing and understanding single‐atom catalysts for heterogeneous oxidation reactions

Simultaneous determination of prodrug of Ginkgolide B and Ginkgolide B in rat plasma by LC-MS/MS

A simple and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was established and validated for the determination of prodrug of ginkgolide B (PGB) and its metabolite, ginkgolide B (GB) in rat plasma. The separation was achieved on a Waters Symmetry Shield RP18 column (150 mm × 3.9 mm i.d., 5 μm particle size), using a mobile phase composed of methanol/water with 10 mM ammonium acetate (85:15, v/v) at a flow rate of 800 μL/min in 2 min. An API 3200 triple quadrupole mass spectrometer equipped with electrospray ionization source was operated in negative ionization mode. Multiple reaction monitoring (MRM) was performed to quantify PGB, GB and the internal standard (IS) at m/z transitions of 528.1 → 122.0, 423.4 → 367.3, 407.5 → 351.2, respectively. A good linearity was found. Intra- and inter-day precision, accuracy, extraction recovery, matrix effect and stability were validated to be within an acceptable range. The developed method was successfully applied to a pharmacokinetic study after intravenous administration of a 10 mg/kg dose of PGB to rats.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Kalirin-7 plays the neuroprotective role in Neuro-2A cells injured by oxygen-glucose deprivation and reperfusion through Rac1 activation

Objective(s): The study explored the neuroprotective role of Kalirin-7 (Kal-7) in Neuro-2A cells after oxygen-glucose deprivation and reperfusion (OGD/R) treatment.Materials and Methods: The study used an OGD/R model of mouse Neuro-2A neuroblastoma cells in vitro. Cells were transfected with pCAGGS-Kal-7 to up-regulating kal-7. Then cell proliferation and apoptosis were respectively analyzed by Trypan blue exclusion method and flow cytometry. To examine the involvement of Rac1, cells were treated with Rac1-GTP inhibitor NSC23766 before treatment with OGD/R. Expressions of Bax, Bcl-2, Rac1, and down-stream targets of Rac1 were analyzed by Western blot.Results: Kal-7 significantly decreased OGD/R induced cell apoptosis (

Understanding the promotional effect of Mn2O3 on micro-/mesoporous hybrid silica nanocubic-supported Pt catalysts for the low-temperature destruction of methyl ethyl ketone: An experimental and theoretical study

Pt0.3Mnx/SiO2 nanocubic (nc) micro-/mesoporous composite catalysts with varied Mn contents were synthesized and tested for the oxidation of methyl ethyl ketone (MEK). Results show that MEK can be efficiently decomposed over synthesized Pt0.3Mnx/SiO2-nc materials with a reaction rate and turnover frequency respectively higher than 12.7 mmol gPt–1 s–1 and 4.7 s–1 at 100 °C. Among these materials, the Pt0.3Mn5/SiO2-nc catalyst can completely oxidize MEK at just 163 °C under a high space velocity of 42600 mL g–1 h–1. The remarkable performance of these catalysts is attributed to a synergistic effect between the Pt nanoparticles and Mn2O3. NH3-TPD and NH3-FT-IR experiments revealed that exposed Mn2O3 (222) facets enhance the quantity of Brønsted acid sites in the catalyst, which are considered to be responsible for promoting the desorption of surface-adsorbed O2 and CO2. It is suggested that the desorption of these species liberates active sites for MEK molecules to adsorb and react. 18O2 isotopic labeling experiments revealed that the presence of a Pt–O–Mn moiety weakens the Mn–O bonding interactions, which ultimately promotes the mobility of lattice oxygen in the Mn2O3 system. It was determined that the Mn4+/Mn3+ redox cycle in Mn2O3 allows for the donation of electrons to the Pt nanoparticles, enhancing the proportion of Pt0/Pt2+ and in turn increasing the activity and stability of catalyst. In situ DRIFTS, online FT-IR, and DFT studies revealed that acetone and acetaldehyde are the main intermediate species formed during the activation of MEK over the Pt0.3Mn5/SiO2-nc catalyst. Both intermediates were found to partake in sequential reactions resulting in the formation of H2O and CO2 via formaldehyde

Tumor-secreted lactate contributes to an immunosuppressive microenvironment and affects CD8 T-cell infiltration in glioblastoma

IntroductionGlioblastoma is a malignant brain tumor with poor prognosis. Lactate is the main product of tumor cells, and its secretion may relate to immunocytes’ activation. However, its role in glioblastoma is poorly understood. MethodsThis work performed bulk RNA-seq analysis and single cell RNA-seq analysis to explore the role of lactate in glioblastoma progression. Over 1400 glioblastoma samples were grouped into different clusters according to their expression and the results were validated with our own data, the xiangya cohort. Immunocytes infiltration analysis, immunogram and the map of immune checkpoint genes’ expression were applied to analyze the potential connection between the lactate level with tumor immune microenvironment. Furthermore, machine learning algorithms and cell-cell interaction algorithm were introduced to reveal the connection of tumor cells with immunocytes. By co-culturing CD8 T cells with tumor cells, and performing immunohistochemistry on Xiangya cohort samples further validated results from previous analysis.DiscussionIn this work, lactate is proved that contributes to glioblastoma immune suppressive microenvironment. High level of lactate in tumor microenvironment can affect CD8 T cells’ migration and infiltration ratio in glioblastoma. To step further, potential compounds that targets to samples from different groups were also predicted for future exploration

Catalytic oxidation of 1,2-dichloroethane over three-dimensional ordered meso-macroporous Co 3 O 4 /La 0.7 Sr 0.3 Fe 0.5 Co 0.5 O 3 : destruction route and mechanism

Three-dimensional ordered meso-macroporous La0.7Sr0.3Fe0.5Co0.5O3 (3DOM LSFCO)-supported Co3O4 catalysts were designed and prepared via a PMMA-templating strategy for the total oxidation of 1,2-dichloroethane (1,2-DCE). The physicochemical properties of all synthesized samples were characterized by XRD, FE-SEM, TEM, HAADF-STEM, low-temperature N2 sorption, XPS, H2-TPR, and in situ FT-IR. The introduction of Co3O4 increases the generation rate of oxygen vacancy, playing a crucial role in adsorption and activation of oxygen species. The special 3DOM structure of perovskite-type oxide promotes 1,2-DCE molecules to effectively and intimately contact with the surface adsorbed oxygen over supported catalysts and further accelerates the redox process. Compared with pure LSFCO, all the Co3O4 supported catalysts show superior catalytic performance with reaction rate increases from 5.53 × 10−12 to 2.29 × 10−11 mol g−1 s−1 and Ea decreases from 74.7 to 22.6 KJ mol−1. Amongst, the 10Co3O4/3DOM LSFCO catalyst exhibits the best catalytic activity, highest resistance to chlorine poisoning and lowest by-products concentration because of the largest amount of surface adsorbed oxygen. CO2, CO, HCl, and Cl2 are the main oxidation productions, while some typical reaction intermediates such as vinyl chloride, 1,1,2-trichloroethane and trichloroethylene are also observed, especially over the 3DOM LSFCO sample. Furthermore, the reaction mechanism of 1,2-DCE oxidation over obtained catalysts was proposed based on the results of gas chromatography, in situ FT-IR, and on-line MS. It is believed that the Co3O4/3DOM LSFCO are promising catalysts for the total removal of chlorinated volatile organic compounds