No abstract

The renin-angiotensin system (RAS) is crucial for the physiology and pathology of all the organs. Angiotensinconverting enzyme 2 (ACE2) maintains the homeostasis of RAS as a negative regulator. Recently, ACE2 was identified as the receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the coronavirus that is causing the pandemic of Coronavirus disease 2019 (COVID-19). Since SARS-CoV-2 must bind with ACE2 before entering the host cells in humans, the distribution and expression of ACE2 may be critical for the target organ of the SARS-CoV-2 infection. Moreover, accumulating evidence has demonstrated the implication of ACE2 in the pathological progression in tissue injury and several chronic diseases, ACE2 may also be essential in the progression and clinical outcomes of COVID-19. Therefore, we summarized the expression and activity of ACE2 in various physiological and pathological conditions, and discussed its potential implication in the susceptibility of SARS-CoV-2 infection and the progression and prognosis of COVID-19 patients in the current review.

This paper studies panoptic segmentation, a recently proposed task which segments foreground (FG) objects at the instance level as well as background (BG) contents at the semantic level. Existing methods mostly dealt with these two problems separately, but in this paper, we reveal the underlying relationship between them, in particular, FG objects provide complementary cues to assist BG understanding. Our approach, named the Attention-guided Unified Network (AUNet), is a unified framework with two branches for FG and BG segmentation simultaneously. Two sources of attentions are added to the BG branch, namely, RPN and FG segmentation mask to provide object-level and pixellevel attentions, respectively. Our approach is generalized to different backbones with consistent accuracy gain in both FG and BG segmentation, and also sets new state-of-thearts both in the MS-COCO (46.5% PQ) and Cityscapes (59.0% PQ) benchmarks.

No abstract

Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein – wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor – for which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region.

The thickness and porosity of TiO 2 mesoporous film were optimized for better distribution of quantum dots to enhance the performance of CdS/CdSe quantum dot cosensitized solar cells. The CdS and CdSe quantum dots were prepared on TiO 2 mesoporous film through a successive ion layer absorption and reaction (SILAR) method and a chemical bath deposition (CBD) method, respectively. It was found that the distribution of quantum dots was inhomogeneous from the surface to the interior of the TiO 2 film, being mainly concentrated at the upper layer of the TiO 2 film. As a result, simply increasing film thickness did not make significant contribution to improving solar cell efficiency since only a small portion of quantum dots might access the interior of the film, leading to an exposure of TiO 2 nanoparticles in electrolyte and thus reducing the electron lifetime due to increased charge recombination rate. Our study revealed that the efficiency could reach its maximum, ∼4.62%, with the TiO 2 film, the thickness of which was around 11 μm, and porosity was optimized by adding 12 wt % ethyl cellulose into the paste for making the TiO 2 film.

Lithium-ion batteries (LIBs) have attracted considerable attention due to their wide applications, such as in portable electronic devices, implantable medical devices, and electric vehicles (EVs). [ 1 ] To meet the constantly increasing demands of upcoming electronic devices, new LIBs require substantial improvements in energy capacity, cycling stability, and rate capability of both the cathode and anode materials. [ 2,3 ] Among cathode materials for LIBs, orthorhombic vanadium pentoxide (V 2 O 5 ) the most stable form in the vanadium oxide family, has gained great interest due to its high energy density, low cost, abundant sources, and good safety properties. [4][5][6][7] The theoretical capacity of V 2 O 5 with two Li intercalations/ deintercalations is about 294 mA h g − 1 , much higher than those of more commonly used cathode materials, making it a very promising cathode material for next-generation LIBs. However, the practical use of V 2 O 5 as cathode materials for LIBs has been hampered due to its poor cycling stability, low electronic and ionic conductivity, and slow electrochemical kinetics. [8][9][10] To overcome these problems, decreasing their particle size to nanoscale level is generally believed to be one of the most effective approaches due to the shorter transport lengths for both electrons and Li ions, larger electrode/electrolyte contact area, and better accommodation of the strain of Li intercalation/deintercalation in nanomaterials. [ 11 , 12 ] The unique performance of nanomaterials lies in their large specifi c surface and favorable structural properties. 2D nanosheets often possess large exposed surfaces and specifi c facets, which make them more attractive in energy conversion devices. [ 13 ] 2D structures are ideal frameworks for fast Li storage, which requires stability, large active surface area, and short transport path for Li intercalation/deintercalation. [ 14 ] There have been many researches on nanostructured V 2 O 5 materials for LIBs. [ 4-7 , 15-20 ] However, there are few reports on 2D nanostructured V 2 O 5 for LIBs. The only report on 2D nanostructured V 2 O 5 was that Zhang's group prepared large-area pure V 2 O 5 nanosheets by dissolution-splitting method from their parent bulk cyrstal using ammonium persulfate as intercalated compound. [ 21 ] The method is a typical top-down method. The as-prepared product exhibits enhanced lithium storage properties including high reversible capacity, good cycling, and rate performance.In this communication, we demonstrate a novel and facile green method to prepare 2D leaf-like V 2 O 5 nanosheets as illustrated in Figure 1 . V 2 O 5 powders were reacted with H 2 O 2 in combination with ultrasonic treatment to generate V 2 O 5 gel. Then the V 2 O 5 gel was diluted, freeze-dried, and further treated at 450 ° C in air to obtain V 2 O 5 nanosheets. Used as cathode material for LIBs, this 2D leaf-like V 2 O 5 nanosheets exhibits excellent Li storage properties, including high reversible capacity, high rate capability, and good capacity reten...

Homogeneous Sn-doped V 2 O 5 sol was prepared by the sol−gel method with H 2 O 2 , V 2 O 5 , and SnCl 4 •5H 2 O as precursors, and the films were fabricated by drop-casting, drying at ambient, and then annealing at 450 °C in air for 2 h. X-ray photoelectron spectroscopy (XPS) reveals that the Sn-doped V 2 O 5 film contains 10% V 4+ likely compensates with the accommodation of Sn 4+ ions. Electrochemical and lithium-ion intercalation properties of both the pure and Sn-doped V 2 O 5 films are systematically studied by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronopotentiometry (CP) tests. The Sn-doped V 2 O 5 film shows much enhanced lithium-ion storage capacity, faster kinetics, and improved cyclic stability in comparison with pure V 2 O 5 film. For example, after 50 cycles, the specific capacity of the Sn-doped V 2 O 5 film retains 334 mAh g −1 with a current density of 500 mA g −1 , much higher than 157 mAh g −1 of the pure V 2 O 5 film. Sn-doping is found to reduce the electrochemical reaction resistance, increase the electrochemical reaction reversibility, and enhance the lithium-ion diffusivity. The possible explanation for such significant enhancement in lithium-ion intercalation capacity and cyclic stability of the Sn-doped V 2 O 5 film is discussed.