Relative Extensions of Modules and Homology Groups

We introduce the concepts of relative (co)extensions of modules and explore the relationship between the relative (co)extensions of modules and relative (co)homology groups. Some applications are given.Введено поняття відносних (спів)розширень модулів та вивчено взаємозв'язок між відносними (спів)розширеннями модулів та відносними (ко)гомологічними групами

Employing a Narrow-Band-Gap Mediator in Ternary Solar Cells for Enhanced Photovoltaic Performance.

Ternary organic solar cells (OSCs) provide a convenient and effective means to further improve the power conversion efficiency (PCE) of binary ones via composition control. However, the role of the third component remains to be explored in specific binary systems. Herein, we report ternary blend solar cells by adding the narrow-band-gap donor PCE10 as the mediator into the PBDB-T:IDTT-T binary blend system. The extended absorption, efficient fluorescence resonance energy transfer, enhanced charge dissociation, and induced tighter molecular packing of the ternary blend films enhance the photovoltaic properties of devices and deliver a champion PCE of 10.73% with an impressively high open-circuit voltage (VOC) of 1.03 V. Good miscibility and similar molecular packing behavior of the components guarantee the desired morphology in the ternary blend films, leading to solar cell devices with over 10% PCEs at a range of compositions. Our results suggest that ternary systems with properly aligned energy levels and overlapping absorption among the components hold great promises to further enhance the performance of corresponding binary ones

Dense Teacher: Dense Pseudo-Labels for Semi-supervised Object Detection

To date, the most powerful semi-supervised object detectors (SS-OD) are based on pseudo-boxes, which need a sequence of post-processing with fine-tuned hyper-parameters. In this work, we propose replacing the sparse pseudo-boxes with the dense prediction as a united and straightforward form of pseudo-label. Compared to the pseudo-boxes, our Dense Pseudo-Label (DPL) does not involve any post-processing method, thus retaining richer information. We also introduce a region selection technique to highlight the key information while suppressing the noise carried by dense labels. We name our proposed SS-OD algorithm that leverages the DPL as Dense Teacher. On COCO and VOC, Dense Teacher shows superior performance under various settings compared with the pseudo-box-based methods.Comment: ECCV202

Characterization of the ompL1 gene of pathogenic Leptospira species in China and cross-immunogenicity of the OmpL1 protein

<p>Abstract</p> <p>Background</p> <p>The usefulness of available vaccine and serological tests for leptospirosis is limited by the low cross-reactivity of antigens from numerous serovars of pathogenic <it>Leptospira </it>spp. Identification of genus-specific protein antigens (GP-Ag) of <it>Leptospira </it>would be important for development of universal vaccines and serodiagnostic methods. OmpL1, a transmembrane porin of pathogenic leptospires, was identified as a possible GP-Ag, but its sequence diversity and immune cross-reactivity among different serovars of pathogenic leptospires remains largely unknown.</p> <p>Results</p> <p>PCR analysis demonstrated that the <it>ompL1 </it>gene existed in all 15 official Chinese standard strains as well as 163 clinical strains of pathogenic leptospires isolated in China. In the standard strains, the <it>ompL1 </it>gene could be divided into three groups (<it>ompL1/1</it>, <it>ompL1/2 </it>and <it>ompL1/3</it>) according to their sequence identities. Immune electron microscopy demonstrated that all products of the different gene types of <it>ompL1 </it>are located on the surface of leptospires. The microscopic agglutination test revealed extensive yet distinct cross-immunoagglutination among the antisera against recombinant OmpL1 (rOmpL1) and leptospiral strains belonging to different <it>ompL1 </it>gene types. These cross-immunoreactions were further verified by ELISAs using the OmpL1 proteins as the coated antigens in serum samples from 385 leptospirosis patients. All the antisera against rOmpL1 proteins could inhibit <it>L. interrogans </it>strain Lai from adhering to J774A.1 cells. Furthermore, immunization of guinea pigs with each of the rOmpL1 proteins could cause cross-immunoprotection against lethal challenge with leptospires from different <it>ompL1 </it>gene types.</p> <p>Conclusion</p> <p>Three types of the <it>ompL1 </it>gene are present in pathogenic leptospires in China. OmpL1 is an immunoprotective GP-Ag which should be considered in the design of new universal vaccines and serodiagnostic methods against leptospirosis.</p

Reticular Synthesis of Multinary Covalent Organic Frameworks.

Hexagonal hexaminophenyl benzene, tetragonal tetrakis(4-aminophenyl) ethane, and trigonal 1,3,5-tris(p-formylphenyl)benzene were all joined together by imine linkages to yield a 2D porous covalent organic framework with unprecedented tth topology, termed COF-346. Unlike the 5 simple existing 2D topologies reported in COFs, COF-346 has 3 kinds of vertices and 2 kinds of edges and is constructed with linkers of 3 kinds of connectivity, and thus represents a higher degree of complexity in COF structures. The success in crystallizing COF-346 was based on precisely chosen geometry and metrics of the linkers and error correction offered by dynamic imine formation. We also report two additional related COFs: a crystalline, porous COF, termed COF-360 with a rare kgd topology, as well as the first crystalline, porous COF with defected tth topology, termed COF-340