Publications by authors named "An-Ping Li"

Nanopores embedded within monolayer hexagonal boron nitride (-BN) offer possibilities of creating atomically thin ceramic membranes with unique combinations of high permeance (atomic thinness), high selectivity (via molecular sieving), increased thermal stability, and superior chemical resistance. However, fabricating size-selective nanopores in monolayer -BN via scalable top-down processes remains nontrivial due to its chemical inertness, and characterizing nanopore size distribution over a large area remains extremely challenging. Here, we demonstrate a facile and scalable approach of exploiting the chemical vapor deposition (CVD) process temperature to enable direct incorporation of subnanometer/nanoscale pores into the monolayer -BN lattice, in combination with manufacturing compatible polymer casting to fabricate centimeter-scale nanoporous atomically thin ceramic membranes.

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The development of robust and efficient single-photon emitters (SPEs) at telecom wavelengths is critical for advancements in quantum information science. Two-dimensional (2D) materials have recently emerged as promising sources for SPEs, owing to their high photon extraction efficiency, facile coupling to external fields, and seamless integration into photonic circuits. In this study, we demonstrate the creation of SPEs emitting in the 1000-1550 nm near-infrared range by coupling 2D indium selenide (InSe) with strain-inducing nanopillar arrays.

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Atomically thin 2D materials present the potential for advancing membrane separations via a combination of high selectivity (from molecular sieving) and high permeance (due to atomic thinness). However, the creation of a high density of precise nanopores (narrow-size-distribution) over large areas in 2D materials remains challenging, and nonselective leakage from nanopore heterogeneity adversely impacts performance. Here, we demonstrate protein-enabled size-selective defect sealing (PDS) for atomically thin graphene membranes over centimeter scale areas by leveraging the size and reactivity of permeating proteins to preferentially seal larger nanopores (≥4 nm) while preserving a significant amount of smaller nanopores (via steric hindrance).

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Background: Fungal diseases present a significant threat to global agriculture, necessitating the development of new, safe, and effective fungicides. Existing fungicides face resistance and health risks, prompting the synthesis of novel compounds. Researchers have synthesized aldehyde-based thiourea and thiazolyl hydrazine derivatives, evaluating their antifungal activities to identify impactful pesticide molecules.

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Naturally derived compounds show promise as treatments for microbial infections. Polyphenols, abundantly found in various plants, fruits, and vegetables, are noted for their physiological benefits including antimicrobial effects. This study introduced a new set of acylated phloroglucinol derivatives, synthesized and tested for their antifungal activity in vitro against seven different pathogenic fungi.

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Article Synopsis
  • Researchers are exploring how to synthesize graphene nanoribbons (GNRs) of specific shapes and sizes using specially designed fluorine-bearing molecular precursors, which are important for electronic applications.
  • The study focuses on the optimal temperature needed for the deposition of a new precursor (CHFI) that leads to the formation of GNRs on gold substrates (Au(111)), revealing that lower temperatures hinder adsorption.
  • Through techniques like scanning tunneling microscopy and X-ray photoelectron spectroscopy, the research explains the growth mechanisms of GNRs and sets the groundwork for creating them on nonmetallic materials in the future.
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, a traditional Chinese herb, produces a wide range of secondary metabolites with a broad spectrum of biological activities. In this study, we isolated six isopentenyl flavonoids from the roots of and evaluated their activities against phytopathogenic fungi. In vitro activities showed that kurarinone and sophoraflavanone G displayed broad spectrum and superior activities, among which sophoraflavanone G displayed excellent activity against tested fungi, with EC values ranging from 4.

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  • Most 2D materials studied are hexagonal, but researchers have successfully created a metastable pentagonal 2D material called monolayer pentagonal PdTe.
  • This material was synthesized using symmetry-driven epitaxy and characterized through scanning tunneling microscopy and spectroscopy, showing stable low-symmetry atomic structures.
  • Theoretical analyses suggest that monolayer pentagonal PdTe is a semiconductor with a 1.05 eV indirect bandgap, paving the way for future pentagon-based 2D materials and their potential applications in nanoelectronics.
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A two-dimensional (2D) Weyl semimetal, akin to a spinful variant of graphene, represents a topological matter characterized by Weyl fermion-like quasiparticles in low dimensions. The spinful linear band structure in two dimensions gives rise to distinctive topological properties, accompanied by the emergence of Fermi string edge states. We report the experimental realization of a 2D Weyl semimetal, bismuthene monolayer grown on SnS(Se) substrates.

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The unique spin texture of quantum states in topological materials underpins many proposed spintronic applications. However, realizations of such great potential are stymied by perturbations, such as temperature and local fields imposed by impurities and defects, that can render a promising quantum state uncontrollable. Here, we report room-temperature scanning tunneling microscopy/spectroscopy observation of interaction between Rashba states and topological surface states, which manifests local electronic structure along step edges controllable by the layer thickness of thin films.

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We report an algorithm to identify and correct distorted wavefronts in atomic resolution scanning tunneling microscope images. This algorithm can be used to correct nonlinear in-plane distortions without prior knowledge of the physical scanning parameters, the characteristics of the piezoelectric actuator, or individual atom positions. The 2D image is first defined as a sum of sinusoidal plane waves, where a nonlinear distortion renders a curve for an otherwise ideal linear wavefront.

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Uncovering the ecological effectiveness of nature reserve policies will help protect and manage nature reserves in the future. Taking Sanjiangyuan region as an example, we examined the impacts of the spatial layout characteristics of natural reserves on the ecological environment quality by constructing the dynamic degree of land use and land cover change index, and depicted the spatial differences of the ecological effectiveness of natural reserve policies both inside and outside the natural reserves. Combined with ordinary least squares and field survey results, we explored the influencing mechanism of nature reserve policies on ecological environment quality.

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The interface between 2D topological Dirac states and an s-wave superconductor is expected to support Majorana-bound states (MBS) that can be used for quantum computing applications. Realizing these novel states of matter and their applications requires control over superconductivity and spin-orbit coupling to achieve spin-momentum-locked topological interface states (TIS) which are simultaneously superconducting. While signatures of MBS have been observed in the magnetic vortex cores of bulk FeTe Se , inhomogeneity and disorder from doping make these signatures unclear and inconsistent between vortices.

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Controlling the interlayer coupling in two-dimensional (2D) materials generates novel electronic and topological phases. Its effective implementation is commonly done with a transverse electric field. However, phases generated by high displacement fields are elusive in this standard approach.

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As the most difficult to control in plant disease, phytopathogenic bacteria cause huge losses to agricultural products and economy worldwide. However, the commercially available bactericides are few and enhance pathogen resistance. To alleviate this situation, 50 flavonoids were evaluated for their antibacterial activities and mechanism of action against two intractable plant bacterial pathogens.

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Quantum coupling in arrayed nanostructures can produce novel mesoscale properties such as electronic minibands to improve the performance of optoelectronic devices, including ultra-efficient solar cells and infrared photodetectors. Colloidal PbSe quantum dots (QDs) that self-assemble into epitaxially-fused superlattices (epi-SLs) are predicted to exhibit such collective phenomena. Here, we show the emergence of distinct local electronic states induced by crystalline necks that connect individual PbSe QDs and modulate the bandgap energy across the epi-SL.

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Article Synopsis
  • Water moves through tiny holes called nanoscale capillaries, which are important in things like biology and cleaning water.
  • Scientists studied how water and water vapor travel through super small pores in a special material called graphene, finding that vapor moves way faster than liquid water.
  • The researchers created really thin membranes that allow water vapor to pass through quickly, much better than most products you can buy, while still blocking tiny particles and ions from getting through.
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Angstrom-scale pores introduced into atomically thin 2D materials offer transformative advances for proton exchange membranes in several energy applications. Here, we show that facile kinetic control of scalable chemical vapor deposition (CVD) can allow for direct formation of angstrom-scale proton-selective pores in monolayer graphene with significant hindrance to even small, hydrated ions (K diameter ∼6.6 Å) and gas molecules (H kinetic diameter ∼2.

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The inhibitory effect of tavaborole on the invasion of in grapes and tomatoes, as well as the potential mechanism involved, was discovered in this study. Our findings showed that tavaborole inhibited spore germination and mycelial expansion in vitro and that the control efficiency in vivo on fruit decay was dose-dependent, which was effective in reducing disease severity and maintaining the organoleptic quality of the fruit, such as reducing weight loss and retaining fruit hardness and titratable acid contents during storage. Furthermore, the precise mechanism of action was investigated further.

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  • A series of compounds featuring disulfide bonds and various aromatic heterocycles were created to explore their antimicrobial properties inspired by the biological activity of allicin.
  • One specific compound showed strong antifungal activity with an EC value of 5.92 μg/mL and performed as well as the established drug thiophanate methyl in live tests.
  • This compound not only inhibited fungal growth effectively but also caused noticeable damage to fungal cells, indicating its potential as a more effective antibacterial agent compared to thiodiazole copper with a MIC value of 1.56 μg/mL.
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Background: Farfarae Flos (FF) is a frequently used traditional herbal medicine with outstanding antitussive actions. The adulteration of FF decoction pieces is common.

Objective: This study aimed to study the effect of adulteration on the safety and quality of FF decoction pieces.

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Article Synopsis
  • A new integrated decision tree was developed for assessing the cumulative health risks of heavy metals (Pb, Cd, and As) in food homologous traditional Chinese medicine (TCM) by measuring their concentrations using advanced spectroscopy techniques.
  • The decision tree includes a three-step process that evaluates potential health risks based on hazard quotients, hazard indices, and toxicity modifications, studying 949 batches of TCM food types.
  • Results show concerning HQ values for specific TCM varieties, highlighting the potential health risks of heavy metals, which could exceed safe tolerance levels, thus emphasizing the need for careful regulation in TCM usage.
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Background: The abuse of chemical fungicides not only leads to toxic residues and resistance in plant pathogenic fungi, but also causes environmental pollution and side effects on in humans and animals. Based on the antifungal activities of berberine, seven different types of berberine derivatives (A1-G1) were synthesized, and their antifungal activities against six plant pathogenic fungi were evaluated (Rhizoctonia solani, Botrytis cinerea, Fusarium graminearum, Phytophthora capsici, Sclerotinia sclerotiorum, and Magnaporthe oryzae).

Results: The results for antifungal activities in vitro showed that berberine derivative E1 displayed good antifungal activity against R.

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