64 research outputs found
ECSIC: Epipolar Cross Attention for Stereo Image Compression
In this paper, we present ECSIC, a novel learned method for stereo image
compression. Our proposed method compresses the left and right images in a
joint manner by exploiting the mutual information between the images of the
stereo image pair using a novel stereo cross attention (SCA) module and two
stereo context modules. The SCA module performs cross-attention restricted to
the corresponding epipolar lines of the two images and processes them in
parallel. The stereo context modules improve the entropy estimation of the
second encoded image by using the first image as a context. We conduct an
extensive ablation study demonstrating the effectiveness of the proposed
modules and a comprehensive quantitative and qualitative comparison with
existing methods. ECSIC achieves state-of-the-art performance among stereo
image compression models on the two popular stereo image datasets Cityscapes
and InStereo2k while allowing for fast encoding and decoding, making it highly
practical for real-time applications
The mechanism behind the selection of two different cleavage sites in NAG-NAM polymers.
Peptidoglycan is a giant molecule that forms the cell wall that surrounds bacterial cells. It is composed of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) residues connected by β-(1,4)-glycosidic bonds and cross-linked with short polypeptide chains. Owing to the increasing antibiotic resistance against drugs targeting peptidoglycan synthesis, studies of enzymes involved in the degradation of peptidoglycan, such as N-acetylglucos-aminidases, may expose new, valuable drug targets. The scientific challenge addressed here is how lysozymes, muramidases which are likely to be the most studied enzymes ever, and bacterial N-acetylglucosaminidases discriminate between two glycosidic bonds that are different in sequence yet chemically equivalent in the same NAG-NAM polymers. In spite of more than fifty years of structural studies of lysozyme, it is still not known how the enzyme selects the bond to be cleaved. Using macromolecular crystallography, chemical synthesis and molecular modelling, this study explains how these two groups of enzymes based on an equivalent structural core exhibit a difference in selectivity. The crystal structures of Staphylococcus aureusN-acetylglucosaminidase autolysin E (AtlE) alone and in complex with fragments of peptidoglycan revealed that N-acetylglucosaminidases and muramidases approach the substrate at alternate glycosidic bond positions from opposite sides. The recognition pocket for NAM residues in the active site of N-acetylglucosaminidases may make them a suitable drug target
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