271 research outputs found
Kinase-independent function of RIP1, critical for mature T-cell survival and proliferation.
The death receptor, Fas, triggers apoptotic death and is essential for maintaining homeostasis in the peripheral lymphoid organs. RIP1 was originally cloned when searching for Fas-binding proteins and was later shown to associate also with the signaling complex of TNFR1. Although Fas exclusively induces apoptosis, TNFR1 primarily activates the pro-survival/pro-inflammatory NF-κB pathway. Mutations in Fas lead to lymphoproliferative (lpr) diseases, and deletion of TNFR1 results in defective innate immune responses. However, the function of RIP1 in the adult lymphoid system has not been well understood, primarily owing to perinatal lethality in mice lacking the entire RIP1 protein in germ cells. This current study investigated the requirement for RIP1 in the T lineage using viable RIP1 mutant mice containing a conditional and kinase-dead RIP1 allele. Disabling the kinase activity of RIP1 had no obvious impact on the T-cell compartment. However, T-cell-specific deletion of RIP1 led to a severe T-lymphopenic condition, owing to a dramatically reduced mature T-cell pool in the periphery. Interestingly, the immature T-cell compartment in the thymus appeared intact. Further analysis showed that mature RIP1(-/-) T cells were severely defective in antigen receptor-induced proliferative responses. Moreover, the RIP1(-/-) T cells displayed greatly increased death and contained elevated caspase activities, an indication of apoptosis. In total, these results revealed a novel, kinase-independent function of RIP1, which is essential for not only promoting TCR-induced proliferative responses but also in blocking apoptosis in mature T cells
FastMESH: Fast Surface Reconstruction by Hexagonal Mesh-based Neural Rendering
Despite the promising results of multi-view reconstruction, the recent neural
rendering-based methods, such as implicit surface rendering (IDR) and volume
rendering (NeuS), not only incur a heavy computational burden on training but
also have the difficulties in disentangling the geometric and appearance.
Although having achieved faster training speed than implicit representation and
hash coding, the explicit voxel-based method obtains the inferior results on
recovering surface. To address these challenges, we propose an effective
mesh-based neural rendering approach, named FastMESH, which only samples at the
intersection of ray and mesh. A coarse-to-fine scheme is introduced to
efficiently extract the initial mesh by space carving. More importantly, we
suggest a hexagonal mesh model to preserve surface regularity by constraining
the second-order derivatives of vertices, where only low level of positional
encoding is engaged for neural rendering. The experiments demonstrate that our
approach achieves the state-of-the-art results on both reconstruction and novel
view synthesis. Besides, we obtain 10-fold acceleration on training comparing
to the implicit representation-based methods
End-to-end Weakly-supervised Multiple 3D Hand Mesh Reconstruction from Single Image
In this paper, we consider the challenging task of simultaneously locating
and recovering multiple hands from single 2D image. Previous studies either
focus on single hand reconstruction or solve this problem in a multi-stage way.
Moreover, the conventional two-stage pipeline firstly detects hand areas, and
then estimates 3D hand pose from each cropped patch. To reduce the
computational redundancy in preprocessing and feature extraction, we propose a
concise but efficient single-stage pipeline. Specifically, we design a
multi-head auto-encoder structure for multi-hand reconstruction, where each
head network shares the same feature map and outputs the hand center, pose and
texture, respectively. Besides, we adopt a weakly-supervised scheme to
alleviate the burden of expensive 3D real-world data annotations. To this end,
we propose a series of losses optimized by a stage-wise training scheme, where
a multi-hand dataset with 2D annotations is generated based on the publicly
available single hand datasets. In order to further improve the accuracy of the
weakly supervised model, we adopt several feature consistency constraints in
both single and multiple hand settings. Specifically, the keypoints of each
hand estimated from local features should be consistent with the re-projected
points predicted from global features. Extensive experiments on public
benchmarks including FreiHAND, HO3D, InterHand2.6M and RHD demonstrate that our
method outperforms the state-of-the-art model-based methods in both
weakly-supervised and fully-supervised manners
PUMA amplifies necroptosis signaling by activating cytosolic DNA sensors.
Necroptosis, a form of regulated necrotic cell death, is governed by RIP1/RIP3-mediated activation of MLKL. However, the signaling process leading to necroptotic death remains to be elucidated. In this study, we found that PUMA, a proapoptotic BH3-only Bcl-2 family member, is transcriptionally activated in an RIP3/MLKL-dependent manner following induction of necroptosis. The induction of PUMA, which is mediated by autocrine TNF-α and enhanced NF-κB activity, contributes to necroptotic death in RIP3-expressing cells with caspases inhibited. On induction, PUMA promotes the cytosolic release of mitochondrial DNA and activation of the DNA sensors DAI/Zbp1 and STING, leading to enhanced RIP3 and MLKL phosphorylation in a positive feedback loop. Furthermore, deletion of PUMA partially rescues necroptosis-mediated developmental defects in FADD-deficient embryos. Collectively, our results reveal a signal amplification mechanism mediated by PUMA and cytosolic DNA sensors that is involved in TNF-driven necroptotic death in vitro and in vivo
DGNR: Density-Guided Neural Point Rendering of Large Driving Scenes
Despite the recent success of Neural Radiance Field (NeRF), it is still
challenging to render large-scale driving scenes with long trajectories,
particularly when the rendering quality and efficiency are in high demand.
Existing methods for such scenes usually involve with spatial warping,
geometric supervision from zero-shot normal or depth estimation, or scene
division strategies, where the synthesized views are often blurry or fail to
meet the requirement of efficient rendering. To address the above challenges,
this paper presents a novel framework that learns a density space from the
scenes to guide the construction of a point-based renderer, dubbed as DGNR
(Density-Guided Neural Rendering). In DGNR, geometric priors are no longer
needed, which can be intrinsically learned from the density space through
volumetric rendering. Specifically, we make use of a differentiable renderer to
synthesize images from the neural density features obtained from the learned
density space. A density-based fusion module and geometric regularization are
proposed to optimize the density space. By conducting experiments on a widely
used autonomous driving dataset, we have validated the effectiveness of DGNR in
synthesizing photorealistic driving scenes and achieving real-time capable
rendering
Thickness-shear Frequencies of an Infinite Quartz Plate with Material Property Variation Along the Thickness
Properties of the quartz crystal blank of a resonator is assumed homogeneous,
uniform, and perfect in design, manufacturing, and applications. As end
products, quartz crystal resonators are frequently exposed to gases and liquids
which can cause surface damage and internal degradation of blanks under
increasingly hostile conditions. The combination of service conditions and
manufacturing process including chemical etching and polishing can inevitably
modify the surface of quartz crystal blanks with changes of material
properties, raising the question of what will happen to vibrations of quartz
crystal resonators of thickness-shear type if such modifications to blanks are
to be evaluated for sensitive applications. Such questions have been
encountered in other materials and structures with property variations either
on purpose or as the effect of environmental or natural processes commonly
referred to as functionally graded materials, or FGMs. Analyses have been done
in applications as part of studies on FGMs in structural as well as in acoustic
wave device applications. A procedure based on series solutions has been
developed in the evaluation of frequency changes and features in an infinite
quartz crystal plate of AT-cut with the symmetric material variation pattern
given in a cosine function with the findings that the vibration modes are now
closely coupled. These results can be used in the evaluation of surface damage
and corrosion of quartz crystal blanks of resonators in sensor applications or
development of new structures of resonators.Comment: This is to be presented and published with the 2014 IEEE
International Frequency Control Symposium, May 19-22, 2014, Taipei
International Convention Center, Taipe
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