The "Pull Effect" of a Hanging ZnII on Improving the Four-Electron Oxygen Reduction Selectivity with Co Porphyrin.

Due to the challenge of cleaving O-O bonds at single Co sites, mononuclear Co complexes typically show poor selectivity for the four-electron (4e-) oxygen reduction reaction (ORR). Herein, we report on selective 4e- ORR catalyzed by a Co porphyrin with a hanged ZnII ion. Inspired by Cu/Zn-superoxide dismutase, we designed and synthesized 1-CoZn with a hanging ZnII at the second sphere of a Co porphyrin. Complex 1-CoZn is much more effective than its Zn-lacking analogues to catalyze the 4e- ORR in neutral aqueous solutions, giving an electron number of 3.91 per O2 reduction. With spectroscopic studies, the hanging ZnII was demonstrated to be able to facilitate the electron transfer from CoII to O2, through an electronic "pull effect", to give CoIII-superoxo. Theoretical studies further suggested that this "pull effect" plays crucial roles in assisting O-O bond cleavage. This work is significant to present a new strategy of hanging a ZnII to improve O2 activation and O-O bond cleavage.

YOLO_Bolt: a lightweight network model for bolt detection.

Accurate, fast, and intelligent workpiece identification is of great significance to industrial production. To cope with the limited hardware resources of factory equipment, we have made lightweight improvements based on You Only Look Once v5 (YOLOv5) and proposed a lightweight YOLO named YOLO_Bolt. First, ghost bottleneck lightweight deep convolution is added to the backbone module and neck module of the YOLOv5 detection algorithm to reduce the model volume. Second, the asymptotic feature pyramid network is added to enhance the feature utilization ability, suppress interference information, and improve detection accuracy. Finally, the relationship between the loss function and the decoupling head structure was focused on, and the number of decoupling head layers was redesigned according to different tasks to further improve the detection accuracy of the workpiece detection model. We conducted experimental verification on the MSCOCO 2017 dataset and the homemade bolt dataset. The experimental results show that compared with YOLOv5s, the number of model parameters is only 6.8 M, which is half that of the original model. On the MSCOCO 2017 dataset, the mAP increased by 2.4%. FPS increased by 104 frames/s. On the homemade dataset, the mAP 0.5 increased by 4.2%, and our proposed method is 1.2% higher than the latest YOLOv8s. The improved network can provide effective auxiliary technical support for workpiece detection.

Coordination Tuning of Metal Porphyrins for Improved Oxygen Evolution Reaction.

The nucleophilic attack of water or hydroxide on metal-oxo units forms an O-O bond in the oxygen evolution reaction (OER). Coordination tuning to improve this attack is intriguing but has been rarely realized. We herein report on improved OER catalysis by metal porphyrin 1-M (M=Co, Fe) with a coordinatively unsaturated metal ion. We designed and synthesized 1-M by sterically blocking one porphyrin side with a tethered tetraazacyclododecane unit. With this protection, the metal-oxo species generated in OER can maintain an unoccupied trans axial site. Importantly, 1-M displays a higher OER activity in alkaline solutions than analogues lacking such an axial protection by decreasing up to 150-mV overpotential to achieve 10 mA/cm2 current density. Theoretical studies suggest that with an unoccupied trans axial site, the metal-oxo unit becomes more positively charged and thus is more favoured for the hydroxide nucleophilic attack as compared to metal-oxo units bearing trans axial ligands.

Metal-Corrole-Based Porous Organic Polymers for Electrocatalytic Oxygen Reduction and Evolution Reactions.

Integrating molecular catalysts into designed frameworks often enables improved catalysis. Compared with porphyrin-based frameworks, metal-corrole-based frameworks have been rarely developed, although monomeric metal corroles are usually more efficient than porphyrin counterparts for the electrocatalytic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). We herein report on metal-corrole-based porous organic polymers (POPs) as ORR and OER electrocatalysts. M-POPs (M=Mn, Fe, Co, Cu) were synthesized by coupling metal 10-phenyl-5,15-(4-iodophenyl)corrole with tetrakis(4-ethynylphenyl)methane. Compared with metal corrole monomers, M-POPs displayed significantly enhanced catalytic activity and stability. Co-POP outperformed other M-POPs by achieving four-electron ORR with a half-wave potential of 0.87 V vs. RHE and reaching 10 mA cm-2 OER current density at 340 mV overpotential. This work is unparalleled to develop and explore metal-corrole-based POPs as electrocatalysts.

Simultaneous Targeted Analysis of GGT and Its H-Type mRNA in HepG2 Cells Based on Degradable Silicon Nanomaterials.

Most important physiological processes in live cells are usually maintained by the interaction of multiple related biomolecules; the multi-target simultaneous analysis of these related molecules can better reflect the dynamic changes of their biological regulatory processes, providing more comprehensive information for diseases diagnosis and research. Herein, we have constructed the degradable multifunctional silica nanomaterials from the prepared degradable organic silicon source and further established degradable composite nanoprobes (DCNPs). The low toxicity of DCNPs could reduce the impact on normal physiological processes in cells and achieve the needs of living cell analysis applications; by the loading of the gamma-glutamyltransferase (GGT) activity-identification probe (Cy-GGT) and surface nucleic acid-recognizing molecular beacon (hairpin) modification, the DCNP realized the simultaneous image analysis of GGT and its related H-type mutated GGT mRNA (H-mRNA) in HepG2 cells and their quantitative detection in vitro. Compared with the traditional multi-target analysis strategy, the lack of targets' physiological mechanism connection was improved, and the combined application of small molecular probes and nucleic acid analysis structures was realized under the control of the cross-influence. This strategy is expected to provide a new direction for the design of multi-target analysis in live cells and provide more accurate analytical tools for clinical research and cancer therapy.

A Green-Emission Metal-Organic Framework-Based Nanoprobe for Imaging Dual Tumor Biomarkers in Living Cells.

The modular nature of metal-organic frameworks (MOFs) permits their tunable structure and function for target application, such as in biomedicine. Herein, a green-emission Zr(IV)-MOF (BUT-88) was constructed from a customized luminescent carbazolyl ligand. BUT-88 represents the first bcu-type MOF with both organic linker and metal node in eight connections and shows medium-sized pores, rich accessible linking sites, and good water stability and biocompatibility. In virtue of these merits, BUT-88 was then fabricated into a MOF-based fluorescent nanoprobe, drDNA-BUT-88. Using it, the live-cell imaging of dual tumor biomarkers was achieved for the first time upon a MOF-based probe, offering enhanced detection precision in early cancer diagnosis. Particularly, the probe showed efficient ratiometric fluorescent sensing toward the cytoplasmic biomarker microRNA-21, further improving the detection accuracy at the cellular level. In this work, the elaborate combination of MOF engineering and the fluorescent detection technique has contributed a facile biosensing platform, unlocking more possibilities of MOF chemistry.

Profiles of immune cell infiltration and immune-related genes in the tumor microenvironment of osteosarcoma.

This work aimed to investigate tumor-infiltrating immune cells (TIICs) and immune-associated genes in the tumor microenvironment of osteosarcoma. An algorithm known as ESTIMATE was applied for immune score assessment, and osteosarcoma cases were assigned to the high and low immune score groups. Immune-associated genes between these groups were compared, and an optimal immune-related risk model was built by Cox regression analyses. The deconvolution algorithm (referred to as CIBERSORT) was applied to assess 22 TIICs for their amounts in the osteosarcoma microenvironment. Osteosarcoma cases with high immune score had significantly improved outcome (P<0.01). The proportions of naive B cells and M0 macrophages were significantly lower in high immune score tissues compared with the low immune score group (P<0.05), while the amounts of M1 macrophages, M2 macrophages, and resting dendritic cells were significantly higher (P<0.05). Important immune-associated genes were determined to generate a prognostic model by Cox regression analysis. Interestingly, cases with high risk score had poor outcome (P<0.01). The areas under the curve (AUC) for the risk model in predicting 1, 3 and 5-year survival were 0.634, 0.781, and 0.809, respectively. Gene set enrichment analysis suggested immunosuppression in high-risk osteosarcoma patients, in association with poor outcome.

Green-emitting carbon dot loaded silica nanoparticles coated with DNA-cross-linked hydrogels for sensitive carcinoembryonic antigen detection and effective targeted cancer therapy.

Herein, we have designed bifunctional composite nanospheres for carcinoembryonic antigen (CEA) sensing and targeted drug delivery, based on carbon dot loaded silica nanoparticles coated with DNA-cross-linked hydrogels. As a result, highly sensitive and selective CEA detection was achieved in vitro, and an effective cytotoxic effect was realized in vivo after loading doxorubicin.

A DNA Nanotube-Peptide Biocomplex for mRNA Detection and Its Application in Cancer Diagnosis and Targeted Therapy.

A biocomplex of DNA nanotube-peptide, consisting of six concatenated DNA strands, three locked DNA strands, and a cell-penetrating peptide, is reported. The barrel-structured DNA nanotube-peptide was successfully applied as a codrug-delivery system for targeting cancer therapy. The mucin 1 protein (MUC-1) aptamer is part of a DNA nanotube that can specifically recognize MUC-1 protein on the surface of MCF-7 cells. Cyclo (Arg-Gly-Asp-d-Phe-Lys; cRGD), as a cell-penetrating peptide, facilitates recruitment and uptake of targeting drugs by binding to integrin receptors (αv ß3 ) of the cytomembrane surface. Anticancer drugs doxorubicin (DOX) and paclitaxel (PTX) were loaded into the capsulated DNA nanotube-peptide (CDNP), which was used as codrug cargo models. The as-prepared biocomplex can be utilized not only to deliver drugs, but also to achieve anticancer effects in vivo. Experimental results suggested that the treatment efficacy of the codrug delivery platform (CDNP/DOX/PTX) was better than that of a single-drug delivery platform (CDNP/DOX or CDNP/PTX). This system, which is composed of DNA strands and peptide, has good biocompatibility and biodegradability. Furthermore, the system can readily detect target mRNA in MCF-7 cells in vitro. The detection limits of mRNA are 9.7×10-8 and 1.8×10-8 m with CDNP/DOX and CDNP/PTX-FITC (FITC=fluorescein isothiocyanate), respectively, as probes.