Round-trip Slipping Motion of the Circular Flare Ribbon Evidenced in a Fan-spine Jet

status: publishe

A supramolecular organic framework with ant topology featuring interdigitation and interpenetration

<div><p>H₄BOPTC reacts with IMI to yield a supramolecular organic framework, formulated as [IMIH⁺]₂√[H₂BOPTC^2 −]√0.5H₂O (<b>1</b>) (IMI = imidazole, H₄BOPTC = benzophenone-3,3′,4,4′-tetracarboxylic acid). Single-crystal X-ray diffraction analysis reveals that <b>1</b> shows a novel architecture with two-level hierarchical entanglement. H₂BOPTC^2 − connects to IMIH⁺ through hydrogen bonds, providing 1D ribbon. The basic ribbons are entangled into a 3D net with <b>ant</b> topology. Then the <b>ant</b> nets further interpenetrate to give the final entangled framework. The thermal stability, optical band gap energy and photoluminescent property of <b>1</b> have also been investigated.</p></div

Stereoscopic Observations of an Erupting Mini-filament-driven Two-sided-loop Jet and the Applications for Diagnosing a Filament Magnetic Field

status: publishe

Solvent-Induced Luminescence Variation of Upconversion Nanoparticles

Solvent plays a vital role in the syntheses, purifications, and broad applications of upconversion nanoparticles (UCNPs). In this work, the effect of various dispersive solvents, including single solvents and mixed solvents, on the luminescence properties of NaYF₄:Yb³⁺, Er³⁺ UCNPs was studied systematically. The differences in both upconversion luminescence (UCL) intensities and color outputs of the nanoparticles were observed when dispersing the UCNPs in deuterium oxide, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethanol, or water. The attenuation of the excitation and emission light of the UCNPs caused by absorption of the solvents, as well as the high-frequency vibrational groups of the solvents, such as −OH, −CH₂, and −CH₃ groups, are responsible for the decrease in UCL intensities and increase in the red to green emission intensity ratios (RGR). The changes in water or OH^– ion contents of ethanol/water mixed solvent triggered similar changes in UCL properties. Interestingly, the quenching of the solvents for the UCL cannot be fully eliminated by changing the dispersive solvents once the UCNPs have touched the solvents containing high-frequency vibrational groups. Our work will facilitate the comprehension of the solvent induced luminescence variations of the nanoparticles and provide guidance for their applications

Magnetic Upconversion Luminescent Nanocomposites with Small Size and Strong Super-Paramagnetism: Polyelectrolyte-Mediated Multimagnetic-Beads Embedding

The incorporation of magnetic and upconversion luminescent properties into one single nanostructure is highly desirable in nanomedicine for contrast agents and/or nanotheranostic platforms. Current magnetic upconversion luminescent nanocomposites generally suffer from relatively large size and/or low magnetization, which might induce unsatisfactory colloidal stability, reticuloendothelial system clearance, and limit their applications in biolabeling, sensing, imaging, bioseparation, magnetic targeting, and so on. Herein, we constructed multimagnetic-beads-embedded Fe₃O₄/NaYF₄: Yb, Er nanocomposites to overcome these problems. Polyelectrolyte was introduced as an organic intermediate layer to offset the crystal lattice mismatch between Fe₃O₄ and NaYF₄: Yb, Er. It also acted as the ligand to direct the growth of NaYF₄: Yb, Er on the surface of Fe₃O₄. So-prepared nanocomposites exhibited an average size of 33.8 nm, much smaller than those with magnetic nanoparticle clusters as the core. The saturation magnetization of the nanocomposites is 17.8 emu/g, higher than those following current single magnetic nanoparticle embedded approach. To demonstrate their application potential in bioimaging and theranostics, magnetic field-assisted sensitive upconversion luminescence cell imaging is presented

ALA_PDT Promotes Ferroptosis-Like Death of Mycobacterium abscessus and Antibiotic Sterilization via Oxidative Stress

Mycobacterium abscessus is one of the common clinical non-tuberculous mycobacteria (NTM) that can cause severe skin infection. 5-Aminolevulinic acid photodynamic therapy (ALA_PDT) is an emerging effective antimicrobial treatment. To explore whether ALA_PDT can be used to treat M. abscessus infections, we conducted a series of experiments in vitro. We found that ALA_PDT can kill M. abscesses. Mechanistically, we found that ALA_PDT promoted ferroptosis-like death of M. abscesses, and the ROS scavenger N-Acetyl-L-cysteine (NAC) and ferroptosis inhibitor Ferrostatin-1 (Fer-1) can mitigate the ALA_PDT-mediated sterilization. Furthermore, ALA_PDT significantly up-regulated the transcription of heme oxygenase MAB_4773, increased the intracellular Fe2+ concentration and altered the transcription of M. abscessus iron metabolism genes. ALA_PDT disrupted the integrity of the cell membrane and enhanced the permeability of the cell membrane, as evidenced by the boosted sterilization effect of antibiotics. In summary, ALA_PDT can kill M. abscesses via promoting the ferroptosis-like death and antibiotic sterilization through oxidative stress by changing iron metabolism. The study provided new mechanistic insights into the clinical efficacy of ALA_PDT against M. abscessus

Interplay between Static and Dynamic Energy Transfer in Biofunctional Upconversion Nanoplatforms

Clarification of the energy-transfer (ET) mechanism is of vital importance for constructing efficient upconversion nanoplatforms for biological/biomedical applications. Yet, most strategies of optimizing these nanoplatforms were casually based on a dynamic ET assumption. In this work, we have modeled quantitatively the shell-thickness-dependent interplay between dynamic and static ET in nanosystems and validated the model in a typical biofunctional upconversion nanoplatform composed of NaYF4:Er, Yb/NaYF4 upconversion nanoparticles (UCNPs), and energy-acceptor photosensitizing molecule Rose Bengal (RB). It was determined that with a proper thickness shell, the energy transferred via dynamic ET as well as static ET in this case could be significantly improved by ∼4 and ∼9 fold, respectively, compared with the total energy transferred from bare core UCNPs. Our results shall form the bedrock in designing highly efficient ET-based biofunctional nanoplatform

<i>In vivo</i> tactile stimulation induced Ca²⁺ elevation in <i>C</i>. <i>elegans</i> AMsh cell.

<p>(A) An example of intracellular Ca²⁺ elevation in an AMsh cell induced by a train of tactile stimuli (20 μm, 2 Hz, 5 s). Sample times are indicated in seconds. *, cell body of the AMsh cell. (B) Fluorescence intensities in the cell body of an AMsh cell. (C) Ratio changes in the cell bodies of the AMsh cells. (D) Ratio changes in the process and cell body of an AMsh cell. The Ca²⁺ wave was propagated from the process to the cell body.</p