Learning Spherical Radiance Field for Efficient 360° Unbounded Novel View Synthesis.

Novel view synthesis aims at rendering any posed images from sparse observations of the scene. Recently, neural radiance fields (NeRF) have demonstrated their effectiveness in synthesizing novel views of a bounded scene. However, most existing methods cannot be directly extended to 360° unbounded scenes where the camera orientations and scene depths are unconstrained with large variations. In this paper, we present a spherical radiance field (SRF) for efficient novel view synthesis in 360° unbounded scenes. Specifically, we represent a 3D scene as multiple concentric spheres with different radii. In particular, each sphere encodes its corresponding layered scene into implicit representations and is parameterized with an equirectangular projection image. A shallow multi-layer perceptron (MLP) is then used to infer the density and color from these sphere representations for volume rendering. Moreover, an occupancy grid is introduced to cache the density field and guide the ray sampling, which accelerates the training and rendering procedures by reducing the number of samples along the ray. Experiments show that our method can well fit 360° unbounded scenes and produces state-of-the-art results on three benchmark datasets with less than 30 minutes of training time on a 3090 GPU, surpassing Mip-NeRF 360 with a 400× speedup. In addition, our method achieves competitive performance in terms of both accuracy and efficiency on a bounded dataset. Project page: https://minglin-chen.github.io/SphericalRF.

Single-cell RNA sequencing of anaplastic ependymoma and H3K27M-mutant diffuse midline glioma.

BACKGROUND: Anaplastic ependymoma and H3K27M-mutant diffuse midline glioma are two common subtypes of brain tumors with poor long-term prognosis. The present study analyzed and compared the differences in cell types between two tumors by single-cell RNA sequencing (scRNA-seq) technology. METHODS: ScRNA-seq was performed to profile cells from cancer tissue from anaplastic ependymoma patient and H3K27M-mutant diffuse midline glioma patient. Cell clustering, marker gene identification, cell type annotation, copy number variation analysis and function analysis of differentially expressed genes were then performed. RESULTS: A total of 11,219 cells were obtained from anaplastic ependymoma and H3K27M mutant diffuse midline glioma, and these cells categorized into 12 distinct clusters. Each cell cluster could be characterized with specific cell markers to indicate cellular heterogeneity. Five cell types were annotated in each sample, including astrocyte, oligodendrocytes, microglial cell, neural progenitor cell and immune cell. The cluster types and proportion of cell types were not consistent between the two brain tumors. Functional analyses suggest that these cell clusters are involved in tumor-associated pathways, with slight differences in the cells of origin between the two tumors. In addition, cell communication analysis showed that the NRG3-ERBB4 pair is a key Ligand-receptor pair for anaplastic ependymoma, while in H3K27M-mutant diffuse midline glioma it is the PTN-PTPRZ1 pair that establishes contact with other cells. CONCLUSION: There was intratumor heterogeneity in anaplastic ependymoma and H3K27M mutant diffuse midline glioma, and that the subtype differences may be due to differences in the origin of the cells.

Ultrafast and Low-Power 2D Bi2O2Se Memristors for Neuromorphic Computing Applications.

Memristors that emulate synaptic plasticity are building blocks for opening a new era of energy-efficient neuromorphic computing architecture, which will overcome the limitation of the von Neumann bottleneck. Layered two-dimensional (2D) Bi2O2Se, as an emerging material for next-generation electronics, is of great significance in improving the efficiency and performance of memristive devices. Herein, high-quality Bi2O2Se nanosheets are grown by configuring mica substrates face-down on the Bi2O2Se powder. Then, bipolar Bi2O2Se memristors are fabricated with excellent performance including ultrafast switching speed (<5 ns) and low-power consumption (<3.02 pJ). Moreover, synaptic plasticity, such as long-term potentiation/depression (LTP/LTD), paired-pulse facilitation (PPF), and spike-timing-dependent plasticity (STDP), are demonstrated in the Bi2O2Se memristor. Furthermore, MNIST recognition with simulated artificial neural networks (ANN) based on conductance modification could reach a high accuracy of 91%. Notably, the 2D Bi2O2Se enables the memristor to possess ultrafast and low-power attributes, showing great potential in neuromorphic computing applications.

Preparation of sludge-cyanobacteria composite carbon for synergistically enhanced co-removal of Cu(II) and Cr(VI).

Traditional sludge disposal is currently restricted by the risk of secondary pollution. Sludge carbon material has gained widespread attention because of its low cost and environmentally sustainable properties. However, owing to the high ash content and low-energy density of sludge, sludge pyrolysis alone has certain limitations, and the performance of carbon materials needs to be improved. Herein, a sludge-cyanobacteria composite carbon (SCC) was easily synthesized, and the adsorption process of Cu(II) and Cr(VI) by SCC was examined. SCC-700-2-50% exhibited a high SBET (1047.54 m2/g) and developed pore structure rich in functional groups (such as -NH, -OH, and C-O). The combination of pore structure and functional groups improved the adsorption performance of SCC. The adsorption processes exhibited a synergistic effect in a binary system: the qm of Cu(II) and Cr(VI) were 386 mg/g and 341 mg/g, respectively, and the selectivity of Cu(II) adsorption by SCC was greater than Cr(VI). The adsorption process, examined by SEM-EDS, FTIR, and XPS analysis, indicated that Cu(II) as a cationic interface strengthens Cr(VI) adsorption through electrostatic interaction, and the anion Cr(VI) created a valid electrostatic shield against the electrostatic repulsion between H+ and Cu(II), facilitating Cu(II) adsorption. SCC had great reusability: Cu(II) and Cr(VI) adsorption capacity were 90% and 84%, of the initial adsorption capacity, respectively, after six cycles. This study demonstrates the prospect of SCC as a valid adsorbent for multiple heavy metal contaminations removal.

Ultralight, Elastic, Hybrid Aerogel for Flexible/Wearable Piezoresistive Sensor and Solid-Solid/Gas-Solid Coupled Triboelectric Nanogenerator.

Aerogels have been attracting wide attentions in flexible/wearable electronics because of their light weight, excellent flexibility, and electrical conductivity. However, multifunctional aerogel-based flexible/wearable electronics for human physiological/motion monitoring, and energy harvest/supply for mobile electronics, have been seldom reported yet. In this study, a kind of hybrid aerogel (GO/CNT HA) based on graphene oxide (GO) and carboxylated multiwalled carbon nanotubes (CMWCNTs) is prepared which can not only used as piezoresistive sensors for human motion and physiological signal detections, but also as high performance triboelectric nanogenerator (TENG) coupled with both solid-solid and gas-solid contact electrifications (CE). The repeatedly loading-unloading tests with 20 000 cycles exhibit its high and ultrastable piezoresistive sensor performances. Moreover, when the obtained aerogel is used as the electrode of a TENG, high electric output performance is produced due to the synergistic effect of solid-solid, and gas-solid interface CEs (3D electrification: solid-solid interface CE between the two solid electrification layers; gas-solid interface CE between the inner surface of GO/CNT HA and the air filled in the aerogel pores). This kind of aerogel promises good applications for human physiological/motion monitoring and energy harvest/supply in flexible/wearable electronics such as piezoresistive sensors and flexible TENG.

Summary of diagnostic and characteristic parameters of C0 to C2 patients based on the CEAP2020 classification.

OBJECTIVES: Hemodynamic changes in C0 to C2 according to the clinical/etiological/anatomical/pathophysiological classification have not been analyzed extensively. We intend to investigate the characteristics of early stage venous disease using venous clinical severity score (VCSS), heaviness/ache/swelling/throbbing/itching (HASTI) score and duplex ultrasound (DUS) derived parameters. METHODS: From Aug. 2020 to Jul. 2021, consecutive patients were categorized according to the clinical/etiological/anatomical/pathophysiological 2020 classification. The vein diameter (mm), reflux time (s), cross-sectional area (cm2), peak and mean reflux velocity (cm/s), and total reflux volume (mL) were documented in the superficial system and deep system. VCSS and HASTI scores were assessed and DUS parameters were analyzed. A P value of less than .05 was considered statistically significant. RESULTS: We studied 257 consecutive patients (142 female) with 371 limbs. The mean age was 50.96 ± 13.27 years (range, 20-81 years; median, 53 years) with an average body mass index of 24.03 ± 2.96 kg/m2 (range, 17.00-33.06 kg/m2; median, 23.67 kg/m2). The proportion of clinical (C) category was as followed: 47 C0S (12.67%), 45 C1 (12.13%), and 279 C2 (75.20%). There were 42.6% of C0 and 62.2% of C1 associated with some form of venous reflux, Pr (pathology [P]-reflux). Reflux of the great saphenous vein above the knee (GSVa) was the most commonly affected vein segment from C0-2. C1 differed from C0 only by age and severity scores with a cut-off value of 1 for both VCSS and HASTI. Larger saphenous veins diameter (GSV and small saphenous vein) were seen in Pr (P-reflux) than Pn (P-none) of C0 cases. Larger deep vein diameters (common femoral vein, femoral vein, and popliteal vein) were evident in Pr versus Pn of C1 cases. In C2, the popliteal vein, saphenofemoral junction, and GSVa were dilated in Pr cases. CONCLUSIONS: Both HASTI and VCSS were discriminative from C0 to C2. C0 differed from C1 by age and severity scores as DUS characteristics were not significantly different between the two groups. Vessel diameter played a discriminative role in distinguishing Pn versus Pr cases in each C0-2 category. GSVa was the most frequent reflux segment irrespective of reflux types.

Enhance pore structure of cyanobacteria-based porous carbon by polypropylene to improve adsorption capacity of methylene blue.

Porous carbon obtained by co-pyrolysis of plastic and biomass has received a lot of attention due to its excellent adsorption properties, and the pore structure plays an essential role in adsorption performance, however, the pore structure is still not well understood. Herein, we synthesized cyanobacteria-based porous carbon derived from cyanobacteria and polypropylene plastic by one-step method. CPC-800-30% exhibited a high BET surface area (2140 m2/g), pore volume up to 1.44 cm3/g. PP not only improved the pore structure of porous carbon, but also enriched the types of functional groups, such as O-H, N-H, C=O, and -CH, due to dehydroxylation or amino group decreased, resulting in the hydrogen radicals increased, hence PP had positive effect for biomass during co-pyrolysis. Meanwhile, CPC-800-30% showed excellent methylene blue (MB) adsorption capacity (667 mg/g). This work provided a new strategy for enhancing porous carbon structure via using PP as additive.

Metabolic engineering of Escherichia coli for the production of isobutanol: a review.

With the ongoing depletion of fossil fuel resources and emerging environmental issues, increasing research effort is being dedicated to producing biofuels from renewable substrates. With its advantages over ethanol in terms of energy density, octane number, and hygroscopicity, isobutanol is considered a potential alternative to traditional gasoline. However, as wild-type microorganisms cannot achieve the production of isobutanol with high titers and yields, rational genetic engineering has been employed to enhance its production. Herein, we review the latest developments in the metabolic engineering of Escherichia coli for the production of isobutanol, including those related to the utilization of diverse carbon sources, balancing the redox state, improving isobutanol tolerance, and application of synthetic biology circuits and tools.

CD226 reduces endothelial cell glucose uptake under hyperglycemic conditions with inflammation in type 2 diabetes mellitus.

CD226 is a co-stimulatory adhesion molecule found on immune and endothelial cells. Here, we evaluated a possible role for CD226 in inhibiting glucose uptake in isolated human umbilical vein endothelial cells (HUVECs) and in wild-type (WT) and CD226 knockout (KO) mice with high-fat diet (HFD)-induced type 2 diabetes (T2DM). CD226 expression increased under hyperglycemic conditions in the presence of TNF-α. Furthermore, CD226 knockdown improved glucose uptake in endothelial cells, and CD226 KO mice exhibited increased glucose tolerance. Levels of soluble CD226 in plasma were higher in T2DM patients following an oral glucose tolerance test (OGTT) than under fasting conditions. Our results indicate that low-grade inflammation coupled with elevated blood glucose increases CD226 expression, resulting in decreased endothelial cell glucose uptake in T2DM.

Refilming with depth-inferred videos.

Compared to still image editing, content-based video editing faces the additional challenges of maintaining the spatiotemporal consistency with respect to geometry. This brings up difficulties of seamlessly modifying video content, for instance, inserting or removing an object. In this paper, we present a new video editing system for creating spatiotemporally consistent and visually appealing refilming effects. Unlike the typical filming practice, our system requires no labor-intensive construction of 3D models/surfaces mimicking the real scene. Instead, it is based on an unsupervised inference of view-dependent depth maps for all video frames. We provide interactive tools requiring only a small amount of user input to perform elementary video content editing, such as separating video layers, completing background scene, and extracting moving objects. These tools can be utilized to produce a variety of visual effects in our system, including but not limited to video composition, "predator" effect, bullet-time, depth-of-field, and fog synthesis. Some of the effects can be achieved in real time.