Photonic Hook-Assisted Contrast-Enhanced Super-Resolution Imaging Using Janus Microspheres

Microsphere-assisted imaging is a promising label- free super-resolution imaging technique. Its performance is sig- nificantly affected by the photonic nanojet (PNJ) of microspheres. Recently, a new type of curved PNJ, i.e. the photonic hook (PH), was discovered, which shows promising potential for various applications. This Letter presented a contrast-enhanced super- resolution imaging technique utilizing the PHs generated by Janus microspheres. We demonstrated that the Janus micro- spheres can be fabricated using a one-step deposition process, they exhibit superior imaging performance to pristine micro- spheres, and their field-of-view and imaging contrast can be easily adjusted by changing the coating thickness. In addition, we demonstrated that the imaging contrast of Janus microspheres can be further enhanced by using polarized illumination

Review: A Survey on Objective Evaluation of Image Sharpness

Establishing an accurate objective evaluation metric of image sharpness is crucial for image analysis, recognition and quality measurement. In this review, we highlight recent advances in no-reference image quality assessment research, divide the reported algorithms into four groups (spatial domain-based methods, spectral domain-based methods, learning-based methods and combination methods) and outline the advantages and disadvantages of each method group. Furthermore, we conduct a brief bibliometric study with which to provide an overview of the current trends from 2013 to 2021 and compare the performance of representative algorithms on public datasets. Finally, we describe the shortcomings and future challenges in the current studies

Progress in the Elimination of Organic Contaminants in Wastewater by Activation Persulfate over Iron-Based Metal–Organic Frameworks

The release of organic contaminants has grown to be a major environmental concern and a threat to the ecology of water bodies. Persulfate-based Advanced Oxidation Technology (PAOT) is effective at eliminating hazardous pollutants and has an extensive spectrum of applications. Iron-based metal–organic frameworks (Fe-MOFs) and their derivatives have exhibited great advantages in activating persulfate for wastewater treatment. In this article, we provide a comprehensive review of recent research progress on the significant potential of Fe-MOFs for removing antibiotics, organic dyes, phenols, and other contaminants from aqueous environments. Firstly, multiple approaches for preparing Fe-MOFs, including the MIL and ZIF series were introduced. Subsequently, removal performance of pollutants such as antibiotics of sulfonamides and tetracyclines (TC), organic dyes of rhodamine B (RhB) and acid orange 7 (AO7), phenols of phenol and bisphenol A (BPA) by various Fe-MOFs was compared. Finally, different degradation mechanisms, encompassing free radical degradation pathways and non-free radical degradation pathways were elucidated. This review explores the synthesis methods of Fe-MOFs and their application in removing organic pollutants from water bodies, providing insights for further refining the preparation of Fe-MOFs

A Survey of Multi-Focus Image Fusion Methods

As an important branch in the field of image fusion, the multi-focus image fusion technique can effectively solve the problem of optical lens depth of field, making two or more partially focused images fuse into a fully focused image. In this paper, the methods based on boundary segmentation was put forward as a group of image fusion method. Thus, a novel classification method of image fusion algorithms is proposed: transform domain methods, boundary segmentation methods, deep learning methods, and combination fusion methods. In addition, the subjective and objective evaluation standards are listed, and eight common objective evaluation indicators are described in detail. On the basis of lots of literature, this paper compares and summarizes various representative methods. At the end of this paper, some main limitations in current research are discussed, and the future development of multi-focus image fusion is prospected

Three-Dimensional Modeling of Spun-Bonded Nonwoven Meso-Structures

As a type of fiber system, nonwoven fabric is ideal for solid–liquid separation and air filtration. With the wide application of nonwoven filter materials, it is crucial to explore the complex relationship between its meso structure and filtration performance. In this paper, we proposed a novel method for constructing the real meso-structure of spun-bonded nonwoven fabric using computer image processing technology based on the idea of a “point-line-body”. Furthermore, the finite element method was adopted to predict filtration efficiencies based on the built 3D model. To verify the effectiveness of the constructed meso-structure and simulation model, filtration experiments were carried out on the fabric samples under different pollution particle sizes and inlet velocities. The experimental results show that the trends observed in the simulation results are consistent with those of the experimental results, with a relative error smaller than 10% for any individual datum

Multifunctional Nanoflowers for Simultaneous Multimodal Imaging and High-Sensitivity Chemo-Photothermal Treatment

Liver cancer is currently among the most challenging cancers to diagnose and treat. It is of prime importance to minimize the side effects on healthy tissues and reduce drug resistance for precise diagnoses and effective treatment of liver cancer. Herein, we report a facile but high-yield approach to fabricate a multifunctional nanomaterial through the loading of chitosan and metformin on Mn-doped Fe₃O₄@MoS₂ nanoflowers. Mn-doped Fe₃O₄ cores are used as simultaneous <i>T</i>₁/<i>T</i>₂ magnetic resonance imaging (MRI) agents for sensitive and accurate cancer diagnosis, while MoS₂ nanosheets are used as effective near-infrared photothermal conversion agents for potential photothermal therapy. The surface-functionalized chitosan was able not only to improve the dispersibility of Mn-doped Fe₃O₄@MoS₂ nanoflowers in biofluids and increase their biocompatibility, but also to significantly enhance the photothermal effect. Furthermore, metformin loading led to high suppression and eradication of hepatoma cells when photothermally sensitized, but exhibited negligible effects on normal liver cells. Due to its excellent combination of <i>T</i>₁/<i>T</i>₂ MRI properties with sensitive chemotherapeutic and photothermal effects, our study highlights the promise of developing multifunctional nanomaterials for accurate multimodal imaging-guided, and highly sensitive therapy of liver cancer

One Stone, Two Birds: High-Brightness Aggregation-Induced Emission Photosensitizers for Super-Resolution Imaging and Photodynamic Therapy

Most aggregation-induced emission (AIE) luminogens exhibit high brightness, excellent photostability, and good biocompatibility, but these AIE-active agents, which kill two birds with one stone to result in applications in both stimulated emission depletion (STED) super-resolution imaging and photodynamic therapy (PDT), have not been reported yet but are urgently needed. To meet the requirements of STED nanoscopy and PDT, D-A-π-A-D type DTPABT-HP is designed by tuning conjugated π spacers. It exhibits red-shifted emission, high PLQY of 32.04%, and impressive 1O2 generation (9.24 fold compared to RB) in nanoparticles (NPs). Then, DTPABT-HP NPs are applied in cell imaging via STED nanoscopy, especially visualizing the dynamic changes of lysosomes in the PDT process at ultrahigh resolution. After that, in vivo PDT was also conducted by DTPABT-HP NPs, resulting in significantly inhibited tumor growth, with an inhibition rate of 86%. The work here is beneficial to the design of multifunctional agents and the deep understanding of their phototheranostic mechanism in biological research