565 research outputs found
FineRecon: Depth-aware Feed-forward Network for Detailed 3D Reconstruction
Recent works on 3D reconstruction from posed images have demonstrated that
direct inference of scene-level 3D geometry without test-time optimization is
feasible using deep neural networks, showing remarkable promise and high
efficiency. However, the reconstructed geometry, typically represented as a 3D
truncated signed distance function (TSDF), is often coarse without fine
geometric details. To address this problem, we propose three effective
solutions for improving the fidelity of inference-based 3D reconstructions. We
first present a resolution-agnostic TSDF supervision strategy to provide the
network with a more accurate learning signal during training, avoiding the
pitfalls of TSDF interpolation seen in previous work. We then introduce a depth
guidance strategy using multi-view depth estimates to enhance the scene
representation and recover more accurate surfaces. Finally, we develop a novel
architecture for the final layers of the network, conditioning the output TSDF
prediction on high-resolution image features in addition to coarse voxel
features, enabling sharper reconstruction of fine details. Our method,
FineRecon, produces smooth and highly accurate reconstructions, showing
significant improvements across multiple depth and 3D reconstruction metrics.Comment: ICCV 202
Low Energy Electronic Recoils and Single Electron Detection with a Liquid Xenon Proportional Scintillation Counter
Liquid xenon (LXe) is a well-studied detector medium to search for rare
events in dark matter and neutrino physics. Two-phase xenon time projection
chambers (TPCs) can detect electronic and nuclear recoils with energy down to
kilo-electron volts (keV). In this paper, we characterize the response of a
single-phase liquid xenon proportional scintillation counter (LXePSC), which
produces electroluminescence directly in the liquid, to detect electronic
recoils at low energies. Our design uses a thin (10 - 25 m diameter),
central anode wire in a cylindrical LXe target where ionization electrons,
created from radiation particles, drift radially towards the anode, and
electroluminescence is produced. Both the primary scintillation (S1) and
electroluminescence (S2) are detected by photomultiplier tubes (PMTs)
surrounding the LXe target. Up to 17 photons are produced per electron,
obtained with a 10 m diameter anode wire, allowing for the highly
efficient detection of electronic recoils from beta decays of a tritium source
down to roughly 1 keV. Single electrons, from photo-emission of the cathode
wires, are observed at a gain of 1.8 photoelectrons (PE) per electron. The
delayed signals following the S2 signals are dominated by single-photon-like
hits, without evidence for electron signals observed in the two-phase xenon
TPCs. We discuss the potential application of such a LXePSC for reactor
neutrino detection via Coherent Elastic Neutrino Nucleus Scattering
(CENS).Comment: 18 pages, 17 figure
Visualization of MG53-mediated Cell Membrane Repair Using in vivo and in vitro Systems
Repair of acute injury to the cell membrane is an elemental process of normal cellular physiology, and defective membrane repair has been linked to many degenerative human diseases. The recent discovery of MG53 as a key component of the membrane resealing machinery allows for a better molecular understanding of the basic biology of tissue repair, as well as for potential translational applications in regenerative medicine. Here we detail the experimental protocols for exploring the in vivo function of MG53 in repair of muscle injury using treadmill exercise protocols on mouse models, for testing the ex vivo membrane repair capacity by measuring dye entry into isolated muscle fibers, and for monitoring the dynamic process of MG53-mediated vesicle trafficking and cell membrane repair in cultured cells using live cell confocal microscopy
Muscle aging is associated with compromised Ca2+ spark signaling and segregated intracellular Ca2+ release
Reduced homeostatic capacity for intracellular Ca2+ ([Ca2+]i) movement may underlie the progression of sarcopenia and contractile dysfunction during muscle aging. We report two alterations to Ca2+ homeostasis in skeletal muscle that are associated with aging. Ca2+ sparks, which are the elemental units of Ca2+ release from sarcoplasmic reticulum, are silent under resting conditions in young muscle, yet activate in a dynamic manner upon deformation of membrane structures. The dynamic nature of Ca2+ sparks appears to be lost in aged skeletal muscle. Using repetitive voltage stimulation on isolated muscle preparations, we identify a segregated [Ca2+]i reserve that uncouples from the normal excitation–contraction process in aged skeletal muscle. Similar phenotypes are observed in adolescent muscle null for a synaptophysin-family protein named mitsugumin-29 (MG29) that is involved in maintenance of muscle membrane ultrastructure and Ca2+ signaling. This finding, coupled with decreased expression of MG29 in aged skeletal muscle, suggests that MG29 expression is important in maintaining skeletal muscle Ca2+ homeostasis during aging
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