Publications by authors named "Linhua Xu"

Exosomes can be modified and designed for various therapeutic goals because of their unique physical and chemical characteristics. Researchers have identified tumor-derived exosomes (TEXs) as significant players in cancer by influencing tumor growth, immune response evasion, angiogeneis, and drug resistance. TEXs promote the production of specific proteins important for cancer progression.

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Duck Tembusu virus (DTMUV) is an acute avian flavivirus that primarily infects poultry, mosquitoes, and some mammals including humans. The viral infection triggers reactive oxygen species (ROS) and inflammatory response that are crucial in mediating injury. Crafting multifunctional nanozymes that possess both ROS scavenging and anti-inflammatory activities presents formidable challenges.

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Goose astrovirus (GAstV) is a newly identified viral pathogen threatening waterfowl, exhibiting a high prevalence across various regions in China. Notably, the Guanghan District of Deyang City, situated in Sichuan Province, has faced a outbreak of GAstV, resulting in significant mortality among goslings due to the induction of gout-like symptoms. In our research, we successfully isolated a GAstV strain known as GAstV SCG3.

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Goose astrovirus (GAstV) is a small, non-enveloped, single-stranded, positive-sense RNA virus. GAstV has rapidly spread across various regions in China since 2016. In Sichuan, out of 113 samples were collected from goose diseases between 2019 and 2022, 97 were positive for GAstV through PCR testing.

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Goose astrovirus (GAstV, genus Avian Astrovirus, family Astrovirus) was first discovered in 2005, but was not considered as a pathogen of gosling gout until 2016. Since then, goose astrovirus has erupted in Chinese goslings, causing at most 50% of gosling deaths. By December 2022, the disease had become epidemic and prevailed in goose farms in Jiangsu, Shandong, Anhui, Henan, Guangdong, Liaoning, Sichuan and other places in China.

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An efficient and practical method to construct benzimidazoles via Rh(III)-catalyzed sequential C-H amination and annulation cascade reaction has been developed. The cascade reaction displays high step, atom, and redox economy, is compatible with the air, and has good functional group tolerance and high efficiency. The titled products can be easily further converted into imidazo[4,5-]acridines, which were observed unique fluorescent properties.

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An efficient protocol to synthesize substituted benzo[4,5]imidazo[1,2- c]quinazolines starting from N-LG-2-phenylbenzoimidazole and dioxazolones catalyzed by Rh(III) or Ir(III) has been developed. Various substituted benzo[4,5]imidazo[1,2- c]quinazolines could be easily provided in up to 99% yield. A large range of substrates and functional groups are compatible for this transformation.

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An efficient tandem reaction of imidamides and N-hydroxycarbamates has been developed. Valuable 2-alkylbenzimidazoles could be easily obtained in up to 97% yield for more than 20 examples. The products would further streamline the synthesis of molecules, which are essential building blocks in organic synthesis and drug discovery.

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A polarization-insensitive and angle-independent graphene absorber (GA) with periodically patterned grating is demonstrated. A periodic nanocavity composed of multilayer subwavelength grating and metal substrate supports a strongly localized mode inside the cavity, where the mode helps to absorb more electromagnetic waves. The proposed GA exhibits polarization-insensitive behavior and maintains the high absorption above 90% within a wide range of incident angle (more than 80°).

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A multiline absorber based on the excitation of guided-mode resonance of one-dimensional photonic crystals (1D-PhCs), including a surface graphene monolayer under the attenuated-total-reflection configuration, is proposed and demonstrated. By carefully designing the structure parameters of the 1D-PhCs, the guided mode can be modulated by the periodic distribution of the refractive index. Our results reveal that the critical coupling of the guided resonance in periodical PhCs to graphene produces the perfect absorption.

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A novel Ir-catalyzed annulation of imidamides with sulfonyl azides has been developed. 1,2-Disubstituted benzimidazoles could be easily obtained in up to 99% yield for more than 40 examples. The products further streamline the synthesis of molecules that are important building blocks for organic synthesis and drug discovery.

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Article Synopsis
  • The study presents Raman lasing and the optical analog of electromagnetically-induced transparency (EIT) in a specialized microtoroid resonator that is embedded in a low refractive index polymer with a tapered fiber coupler.
  • The microtoroid resonator enables low-threshold single and multimode Raman lasing, and exhibits Fano and EIT-like phenomena, which can enhance sensor resolution.
  • These findings suggest potential advancements in developing portable and stable WGM microlasers and resonator-based sensors for a variety of practical applications.
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In this work, we show that the application of a sol-gel coating renders a microbubble whispering gallery resonator into an active device. During the fabrication of the resonator, a thin layer of erbium-doped sol-gel is applied to a tapered microcapillary, then a microbubble with a wall thickness of 1.3 μm is formed with the rare earth ions diffused into its wall.

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Frequency comb generation in microresonators at visible wavelengths has found applications in a variety of areas such as metrology, sensing, and imaging. To achieve Kerr combs based on four-wave mixing in a microresonator, dispersion must be in the anomalous regime. In this Letter, we demonstrate dispersion engineering in a microbubble resonator (MBR) fabricated by a two-CO laser beam technique.

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Ir-catalyzed direct C-H sulfamidation of benzaldehydes has been achieved. A series of ortho-amided benzaldehydes were obtained in up to 95% yields for 21 examples with excellent regioselectivity and broad functional group tolerance. This transformation could proceed smoothly with low catalyst loading under external-oxidant-, acid-, or base-free conditions.

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We have experimentally demonstrated an on-chip all-silk fibroin whispering gallery mode microresonator by using a simple molding and solution-casting technique. The quality factors of the fabricated silk protein microresonators are on the order of 10. A high-sensitivity thermal sensor was realized in this silk fibroin microtoroid with a sensitivity of -1.

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A waveguide-coupled surface phonon resonance (SPhR) sensor with super-resolution based on Fano resonance (FR) by using a multilayer system within the Kretschmann configuration in the mid-infrared wavelength region is proposed. Due to the coherent interference of the waveguide and the surface phonon polariton modes, the calculated reflectivity spectrum possesses sharp asymmetric FR dips. An ultra-small linewidth is formed because of the Fano coupling, and the physical features contribute to a highly efficient nano-sensor for refractive index sensing.

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One method for enhancement and manipulation of light absorption with monolayer graphene covered on a single-layer guided mode resonant Brewster filter surface is demonstrated. By means of the rigorous coupled-wave analysis method, the effect of geometrical parameters on the optical response of the structure is investigated. It is possible to achieve a maximum absorption of 60% at the Brewster angle; dual-band optical absorption can also be realized when the depth of the grating is increased.

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A new C3-symmetric Schiff-base fluorescent probe (L) based on 8-hydroxy-2-methylquinoline has been developed. As expected, the probe L can display high fluorescent selectivity for Cd(2+) over Zn(2+) and most other common ions in neutral ethanol aqueous medium. Moreover, the mechanism of the L-Cd(2+) complex has been confirmed by X-ray crystallography and density functional theory calculation results.

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We demonstrate the design of an efficient angle-insensitive guided mode resonance filter (GMRF), with narrow bandwidth and low sideband reflection, for TE-polarized waves. The reflection properties of the multilayer structure have been studied, and the results verify that the thin film design of the gradient-index layer is important for the realization of an angle-insensitive filter. Various gradient coefficients of the thin film have distinct effects on the reflection spectrum.

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The insulin receptor (IR) recruits adaptor proteins, so-called insulin receptor substrates (IRS), to connect with downstream signalling pathways. A family of IRS proteins was defined based on three major common structural elements: Amino-terminal PH and PTB domains that mediate protein-lipid or protein-protein interactions, mostly carboxy-terminal multiple tyrosine residues that serve as binding sites for proteins that contain one or more SH2 domains and serine/threonine-rich regions which may be recognized by negative regulators of insulin action. The current model for the role of IRS proteins therefore combines an adaptor function with the integration of mostly negative input from other signal transduction cascades allowing for modulation of signalling amplitude.

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Protein kinase B (PKB)/Akt is considered to be a key target downstream of insulin receptor substrate 2 (IRS2) in the regulation of beta-cell mass. However, while deficiency of IRS2 in mice results in diabetes with insulin resistance and severe failure of beta-cell mass and function, only loss of the PKBbeta isoform leads to a mild metabolic phenotype with insulin resistance. Other isoforms were reported not to be required for metabolic regulation.

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