Wing dimorphism is a phenomenon of phenotypic plasticity in aphid dispersal. However, the signal transduction for perceiving environmental cues (e.g., crowding) and the regulation mechanism remain ...elusive. Here, we found that aci-miR-9b was the only down-regulated microRNA (miRNA) in both crowding-induced wing dimorphism and during wing development in the brown citrus aphid Aphis citricidus. We determined a targeted regulatory relationship between aci-miR-9b and an ABC transporter (AcABCG4). Inhibition of aci-miR-9b increased the proportion of winged offspring under normal conditions. Overexpression of aci-miR-9b resulted in decline of the proportion of winged offspring under crowding conditions. In addition, overexpression of aci-miR-9b also resulted in malformed wings during wing development. This role of aci-miR-9b mediating wing dimorphism and development was also confirmed in the pea aphid Acyrthosiphon pisum. The downstream action of aci-miR-9b-AcABCG4 was based on the interaction with the insulin and insulin-like signaling pathway. A model for aphid wing dimorphism and development was demonstrated as the following: maternal aphids experience crowding, which results in the decrease of aci-miR-9b. This is followed by the increase of ABCG4, which then activates the insulin and insulin-like signaling pathway, thereby causing a high proportion of winged offspring. Later, the same cascade, “miR-9b-ABCG4-insulin signaling,” is again involved in wing development. Taken together, our results reveal that a signal transduction cascade mediates both wing dimorphism and development in aphids via miRNA. These findings would be useful in developing potential strategies for blocking the aphid dispersal and reducing viral transmission.
The low efficiency triplet emission of hybrid copper(I) iodide clusters is a critical obstacle to their further practical optoelectronic application. Herein, we present an efficient hybrid copper(I) ...iodide cluster emitter (DBA)4Cu4I4, where the cooperation of excited state structure reorganization and the metallophilicity interaction enables ultra‐bright triplet yellow‐orange emission with a photoluminescence quantum yield over 94.9 %, and the phonon‐assisted de‐trapping process of exciton induces the negative thermal quenching effect at 80–300 K. We also investigate the potential of this emitter for X‐ray imaging. The (DBA)4Cu4I4 wafer demonstrates a light yield higher than 104 photons MeV−1 and a high spatial resolution of ≈5.0 lp mm−1, showing great potential in practical X‐ray imaging applications. Our new copper(I) iodide cluster emitter can serve as a model for investigating the thermodynamic mechanism of photoluminescence in hybrid copper(I) halide phosphorescence materials.
The new hybrid copper(I) iodide cluster (DBA)4Cu4I4 enables ultra‐bright triplet yellow‐orange emission with a PLQY>94.9 % by the coaction of excited state structure reorganization and the metallophilicity interaction, and the phonon‐assisted de‐trapping process of exciton induces the negative thermal quenching effect at 80–300 K. Our investigation shows that this material has a great potential in practical X‐ray imaging applications.
Halogen bonding has been used to glue together hydrogen‐bonded short arylamide foldamers to achieve new supramolecular double and quadruple helices in the solid state. Three compounds, which bear a ...pyridine at one end and either a CF2I or fluorinated iodobenzene group at the other end, engage in head‐to‐tail N⋅⋅⋅I halogen bonds to form one‐component supramolecular P and M helices, which stack to afford supramolecular double‐stranded helices. One of the double helices can dimerize to form a G‐quadruplex‐like supramolecular quadruple helix. Another symmetric compound, which bears a pyridine at each end, binds to ICF2CF2I through N⋅⋅⋅I halogen bonds to form two‐component supramolecular P and M helices, with one turn consisting of four (2+2) molecules. Half of the pyridine‐bearing molecules in two P helices and two M helices stack alternatingly to form another supramolecular quadruple helix. Another half of the pyridine‐bearing molecules in such quadruple helices stack alternatingly with counterparts from neighboring quadruple helices, leading to unique quadruple helical arrays in two‐dimensional space.
Glued in place: Halogen bonds glue together short hydrogen‐bonded arylamide molecules to form either one‐ or two‐component helices. The helices stack to produce supramolecular quadruple and double helical structures.
Carbon materials are frequently used to improve the cycle and rate performance of VS4 as anode material for lithium ion batteries. However, the interfacial interaction between VS4 and carbon has not ...been elucidated clearly. Various VS4@C composites are prepared and the interface between VS4 and porous carbon is investigated by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and first‐principles calculations. The interfacial structure between VS4 and carbon and the mechanism of flower‐like VS4 growth on carbon substrate are revealed clearly. The results indicate that C−V bonds and C−O−V bonds are formed when oxygen functional groups are introduced into the porous carbon, and the C−V bonds and C−O−V bonds accelerate the electron transport and enhance structural stability of the VS4@C composite. Deriving from the unique structure and robust interfacial interaction, the electrochemical performances of VS4@C composite are much better than that of pure VS4. Moreover, through the study of lithium storage mechanism of VS4 anode, it is found that there is an irreversible amorphization change of the original VS4 in the first cycle, and that during the following electrochemical process, the main storage behavior of lithium ions derives from the insertion−extraction reactions in the amorphous VS4 with the reaction between V4+ and V3+.
Carbon materials are frequently used to improve the cycle and rate performances of VS4 as anode material for lithium ion batteries. However, the interface between VS4 and carbon is unclear. It is demonstrated that the robust “skeletons” of vanadium−carbon and vanadium−oxygen−carbon between VS4 and carbon material are the origin of this synergistic effect.
The generalized conjugate phase retrieval problem aims to reconstruct a complex signal
x
∈ ℂ
n
from quadratic measurements
x
*
A
1
x
,…,
x
*
A
m
x
, where
A
1
,…,
A
m
∈ ℝ
n
×
n
are real symmetric ...matrices. The equivalent formulation for generalized conjugate phase retrieval along with the minimal measurement number required for accurate retrieval (up to a global phase factor as well as conjugacy) are derived in this paper. We present a set of nine vectors in ℝ
4
and prove that it is conjugate phase retrievable on ℂ
4
. This result implies the measurement number bound 4
n
− 6 is not optimal for some
n
, which confirms a conjecture in the article by Evans and Lai (2019).
To characterize an emergent carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) strain, NUHL30457, which co-produces NDM-1 and KPC-2 carbapenemases.
We performed WGS analysis on a ...clinical carbapenemase-producing hypervirulent K. pneumoniae (CP-hvKP) strain NUHL30457. Sequence data were analysed using comparative genomics and phylogenetics. WGS was used to perform MLST, capsular genotyping and identification of virulence and antimicrobial resistance genes. The virulence of NUHL30457 was analysed by serum killing assay, neutrophil phagocytosis and mouse lethality assay.
The NUHL30457 strain was carbapenem resistant and belonged to ST86 and serotype K2. A significant increase in resistance to serum killing and antiphagocytosis was found in the NUHL30457 strain compared with the reference strain. The murine lethality assay showed an LD50 of 2.5 × 102 cfu for the NUHL30457 strain, indicating hypervirulence. WGS revealed that NUHL30457 has a single 5.3 Mb chromosome (57.53% G + C content) and four plasmids in the range 49.2-215.7 kb. The incompatibility group (Inc)N plasmid p30457-4 carried the blaNDM-1 and qnrS1 genes. The IncFII(K) plasmid p30457-3 also carried an array of resistance elements, including blaCTX-M-65, blaTEM-1 and blaKPC-2. The IncHI1/IncFIB plasmid p30457-1, which carried virulence genes, was identical to a pLVPK plasmid reported previously.
To the best of our knowledge, this is the first report to isolate an ST86 hvKP strain that co-produces NDM-1 and KPC-2 carbapenemase. Further investigation is required to reinforce our understanding of the epidemiology and virulence mechanisms of this clinically significant CP-hvKP.
Porous organic polymers (POPs) have attracted increasing attention and emerged as a new research area in polymer chemistry. During the past decade, the intense desirability for application in aqueous ...scenarios has spawned the development of a specific class of POPs,
, water-soluble or dispersible porous organic polymers (WS-POPs) that can allow the implementation of porosity-based functions in aqueous media. In this Tutorial Review, aiming at providing a practical guide to this area, we will discuss recent advances in the preparation of WS-POPs through covalent/dynamic covalent, coordination and supramolecular approaches. As a result of their intrinsic and well-defined porosity, diverse topological architectures as well as unique water-processable features, many water-soluble/dispersible POPs have been demonstrated to exhibit potential for various applications, which include drug, DNA and protein delivery, bioimaging, photocatalysis, explosive detection and membrane separation. We will also highlight the related function of the representative structures. Finally, we provide our perspective for the future research, with a focus on the development of new structures and biofunctions.
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