683 research outputs found
Delicate Textured Mesh Recovery from NeRF via Adaptive Surface Refinement
Neural Radiance Fields (NeRF) have constituted a remarkable breakthrough in
image-based 3D reconstruction. However, their implicit volumetric
representations differ significantly from the widely-adopted polygonal meshes
and lack support from common 3D software and hardware, making their rendering
and manipulation inefficient. To overcome this limitation, we present a novel
framework that generates textured surface meshes from images. Our approach
begins by efficiently initializing the geometry and view-dependency decomposed
appearance with a NeRF. Subsequently, a coarse mesh is extracted, and an
iterative surface refining algorithm is developed to adaptively adjust both
vertex positions and face density based on re-projected rendering errors. We
jointly refine the appearance with geometry and bake it into texture images for
real-time rendering. Extensive experiments demonstrate that our method achieves
superior mesh quality and competitive rendering quality.Comment: ICCV 2023 camera-ready, Project Page: https://me.kiui.moe/nerf2mes
Real-time Neural Radiance Talking Portrait Synthesis via Audio-spatial Decomposition
While dynamic Neural Radiance Fields (NeRF) have shown success in
high-fidelity 3D modeling of talking portraits, the slow training and inference
speed severely obstruct their potential usage. In this paper, we propose an
efficient NeRF-based framework that enables real-time synthesizing of talking
portraits and faster convergence by leveraging the recent success of grid-based
NeRF. Our key insight is to decompose the inherently high-dimensional talking
portrait representation into three low-dimensional feature grids. Specifically,
a Decomposed Audio-spatial Encoding Module models the dynamic head with a 3D
spatial grid and a 2D audio grid. The torso is handled with another 2D grid in
a lightweight Pseudo-3D Deformable Module. Both modules focus on efficiency
under the premise of good rendering quality. Extensive experiments demonstrate
that our method can generate realistic and audio-lips synchronized talking
portrait videos, while also being highly efficient compared to previous
methods.Comment: Project page: https://me.kiui.moe/radnerf
Two‐Dimensional Design Strategy to Construct Smart Fluorescent Probes for the Precise Tracking of Senescence
The tracking of cellular senescence usually depends on the detection of senescence‐associated β‐galactosidase (SA‐β‐gal). Previous probes for SA‐β‐gal with this purpose only cover a single dimension: the accumulation of this enzyme in lysosomes. However, this is insufficient to determine the destiny of senescence because endogenous β‐gal enriched in lysosomes is not only related to senescence, but also to some other physiological processes. To address this issue, we introduce our fluorescent probes including a second dimension: lysosomal pH, since de‐acidification is a unique feature of the lysosomes in senescent cells. With this novel design, our probes achieved excellent discrimination of SA‐β‐gal from cancer‐associated β‐gal, which enables them to track cellular senescence as well as tissue aging more precisely. Our crystal structures of a model enzyme E. coli β‐gal mutant (E537Q) complexed with each probe further revealed the structural basis for probe recognition.<br/
Molecular Basis of Efficient Replication and Pathogenicity of H9N2 Avian Influenza Viruses in Mice
H9N2 subtype avian influenza viruses (AIVs) have shown expanded host range and can infect mammals, such as humans and swine. To date the mechanisms of mammalian adaptation and interspecies transmission of H9N2 AIVs remain poorly understood. To explore the molecular basis determining mammalian adaptation of H9N2 AIVs, we compared two avian field H9N2 isolates in a mouse model: one (A/chicken/Guangdong/TS/2004, TS) is nonpathogenic, another one (A/chicken/Guangdong/V/2008, V) is lethal with efficient replication in mouse brains. In order to determine the basis of the differences in pathogenicity and brain tropism between these two viruses, recombinants with a single gene from the TS (or V) virus in the background of the V (or TS) virus were generated using reverse genetics and evaluated in a mouse model. The results showed that the PB2 gene is the major factor determining the virulence in the mouse model although other genes also have variable impacts on virus replication and pathogenicity. Further studies using PB2 chimeric viruses and mutated viruses with a single amino acid substitution at position 627 [glutamic acid (E) to lysine, (K)] in PB2 revealed that PB2 627K is critical for pathogenicity and viral replication of H9N2 viruses in mouse brains. All together, these results indicate that the PB2 gene and especially position 627 determine virus replication and pathogenicity in mice. This study provides insights into the molecular basis of mammalian adaptation and interspecies transmission of H9N2 AIVs
Visual analysis of lung neuroendocrine tumors based on CiteSpace knowledge graph
ObjectiveThe relevant literatures in the field of pulmonary neuroendocrine tumor were analyzed to understand the lineage, hot spots and development trends of research in this tumor.MethodThe Web of Science core collection was searched for English-language literature about neuroendocrine tumors of the lung published between 2000 and 2022. CiteSpace software was imported for visualization analysis of countries, institutions, co-cited authors and co-cited journals and sorting of high-frequency keywords, as well as co-cited references and keyword co-occurrence, clustering and bursting display.ResultsA total of 594 publications on neuroendocrine tumours of the lung were available, from 2000 to 2022, with an overall upward trend of annual publications in the literature. Authors or institutions from the United States, Italy, Japan and China were more active in this field, but there was little cooperation among the major countries. Co-cited references and keyword co-occurrence and cluster analysis showed that research on diagnostic instruments, pathogenesis, ectopic ACTH signs, staging and prognosis and treatment was a current research hotspot. The keyword bursts suggested that therapeutic approaches might be a key focus of future research into the field for pulmonary neuroendocrine tumors.ConclusionOver these 20 years, research related to neuroendocrine tumors of the lung has increased in fervour, with research on diagnostic instruments, pathogenesis, ectopic ACTH signs, staging and prognosis, and treatment being the main focus of research. Therapeutic treatments may be the future research trend in this field
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