Propionibacterium acnes Cloaked with ZnAl Layered Double Hydroxides Synergistically Inhibits Tumor Growth and Metastasis

The combination of precise tumor depletion and immunotherapy presents great potential to exterminate cancer disease. Anaerobic bacteria can trigger innate and adaptive immune responses in tumors to facilitate the antitumor effects. However, bacteria injected intravenously induce systemic inflammation and are likely to be eliminated in the blood. Herein, live bacteria, Propionibacterium acnes (P. acnes), are integrated with ZnAl layered double hydroxides (LDHs) to construct an effective system enabling synergistic inhibition in both tumor growth and metastasis. In this system, P. acnes carries LDHs to reach and penetrate the hypoxic tumor tissue. The metabolism of colonized P. acnes and the pH-responsive degradation of LDHs produce reactive nitrogen species and reactive oxygen species to trigger inevitable cell death. Furthermore, the decomposition of LDHs exposes P. acnes, and thus the immune response is activated to prohibit the reoccurrence of distant tumors. The biohybrid P. acnes@LDHs, developed in this study, possesses remarkable anticancer outcomes both in vitro and in vivo.     

Reaction Mechanisms in Platinum-Mediated Electrodynamic Therapy

Electrodynamic therapy (EDT) has emerged as an alternative stimuli-responsive approach for tumor treatment. The current understanding of its mechanism is that an electric field activates water dissociation on platinum nanoparticles (PtNPs) to produce toxic hydroxyl radicals. Nevertheless, the argument here remains that, if without direct contact with electrodes, the equipotential surfaces of PtNPs may hardly trigger electrocatalytic reactions and thus the induction of any radicals. Clearly, the limited understanding of EDT has considerably hindered its current and further explorations. Herein, the fundamental mechanism of EDT is revealed from the view of heterogeneous catalysis. First and foremost, the free chlorine generated during electrolysis is identified as the crucial reactant, which is not observed previously. Through experimental examinations and density functional theory (DFT) calculations, the fundamental reaction is confirmed to be the catalytic activation of HOCl by PtNPs, resulting in the production of oxygen anion radicals and the corrosion of PtNPs. Moreover, the cytotoxicity and intracellular abnormalities further verify the findings and provide new insight into its in vitro anti-cancer mechanism. This study not only assists in re-recognizing the nature of EDT, but also provides core knowledge in guiding its future investigations in catalytic medicine and medical technologies.     

Ultralow-Salt-Concentration Electrolyte for High-Voltage Aqueous Zn Metal Batteries

Aqueous Zn metal batteries are regarded as a promising pathway for large-scale energy storage systems due to their green, low-cost, and intrinsically safe characteristics. However, they have long been suffered from narrow voltage windows and severe parasitic reactions (e.g., hydrogen evolution, corrosion, etc.), which hinder their further development. The above challenges are essentially related to the existence of hydrated ions (i.e., Zn(H₂O)_x²⁺ and SO₄²⁻·(H₂O)_x), which are highly reactive species. Herein, a counterintuitive ultralow-salt-concentration electrolyte strategy to solve the aforementioned problems by decreasing Zn salt concentration to reduce active hydrated ions is presented, so as to minimize water-induced side reactions and thus anomalously enlarge the electrolyte splitting voltage window. Additionally, the gap between the charge and discharge medium voltages of full cells is also narrowed due to the reduced polarization in the ultralow-salt-concentration electrolyte. By adopting this strategy, the Zn-Fe₄[Fe(CN)₆]₃ full cell stably works at a high-voltage of 1.40–2.30 V with a high cathode loading of ≈7 mg cm⁻² and the Zn-polyaniline full cell can stably work at 0.50–1.50 V with a high cathode loading of ≈11 mg cm⁻².     

基于深度学习的行为识别算法综述

人体行为识别一直是计算机视觉研究中的热点.随着近几年人体行为识别在虚拟现实、短视频等方面的广泛应用,以及深度学习算法的快速发展,基于深度学习的行为识别算法层出不穷.相较于传统方法,基于深度学习的行为识别算法具有鲁棒性强、准确率高的优点.基于此,本文对近年来提出的基于深度学习的行为识别算法进行了梳理,并对由双流卷积网络和...     

Efficient Delivery of GSDMD-N mRNA by Engineered Extracellular Vesicles Induces Pyroptosis for Enhanced Immunotherapy (Small 20/2023)

Pyroptosis is a newly discovered inflammatory form of programmed cell death, which promotes systemic immune response in cancer immunotherapy. GSDMD is one of the key molecules executing pyroptosis, while therapeutical delivery of GSDMD to tumor cells is of great challenge. In this study, an extracellular vesicles-based GSDMD-N mRNA delivery system (namely EV^Tx) is developed for enhanced cancer immunotherapy, with GSDMD-N mRNA encapsulated inside, Ce6 (Chlorin e6 (Ce6), a hydrophilic sensitizer) incorporated into extracellular vesicular membrane, and HER2 antibody displayed onto the surface. Briefly, GSDMD-N mRNA is translationally repressed in donor cells by optimized puromycin, ensuring the cell viability and facilitating the mRNA encapsulation into extracellular vesicles. When targeted and delivered into HER2⁺ breast cancer cells by the engineered extracellular vesicles, the translational repression is unleashed in the recipient cells as the puromycin is diluted and additionally inactivated by sonodynamic treatment as the extracellular vesicles are armed with Ce6, allowing GSDMD-N translation and pyroptosis induction. In addition, sonodynamic treatment also induces cell death in the recipient cells. In the SKBR3- and HER2 transfected 4T1- inoculated breast tumor mouse models, the engineered EV^Tx efficiently induces a powerful tumor immune response and suppressed tumor growth, providing a nanoplatform for cancer immunotherapy.     

Monolithic Nickel Catalyst Featured with High-Density Crystalline Steps for Stable Hydrogen Evolution at Large Current Density

Producing hydrogen via electrochemical water splitting with minimum environmental harm can help resolve the energy crisis in a sustainable way. Here, this work fabricates the pure nickel nanopyramid arrays (NNAs) with dense high-index crystalline steps as the cata electrode via a screw dislocation-dominated growth kinetic for long-term durable and large current density hydrogen evolution reaction. Such a monolithic NNAs electrode offers an ultralow overpotential of 469 mV at a current density of 5000 mA cm⁻² in 1.0 m KOH electrolyte and shows a high stability up to 7000 h at a current density of 1000 mA cm⁻², which outperforms the reported catas and even the commercial platinum cata for long-term services under high current densities. Its unique structure can substantially stabilize the high-density surface crystalline steps on the catalytic electrode, which significantly elevates the catalytic activity and durability of nickel in an alkaline medium. In a typical commercial hydrogen gas generator, the total energy conversion rate of NNAs reaches 84.5% of that of a commercial Pt/Ti cata during a 60-day test of hydrogen production. This work approach can provide insights into the development of industry-compatible long-term durable, and high-performance non-noble metal catas for various applications.     

A systematic review on the flavor of soy-based fermented foods: Core fermentation microbiome,multisensory flavor substances,key enzymes,and metabolic pathways

The characteristic flavor of fermented foods has an important impact on the purchasing decisions of consumers, and its production mechanisms are a concern for scientists worldwide. The perception of food flavor is a complex process involving olfaction, taste, vision, and oral touch, with various senses contributing to specific properties of the flavor. Soy-based fermented products are popular because of their unique flavors, especially in Asian countries, where they occupy an important place in the dietary structure. Microorganisms, known as the souls of fermented foods, can influence the sensory properties of soy-based fermented foods through various metabolic pathways, and are closely related to the formation of multisensory properties. Therefore, this review systematically summarizes the core microbiome and its interactions that play an active role in representative soy-based fermented foods, such as fermented soymilk, soy sauce, soybean paste, sufu, and douchi. The mechanism of action of the core microbial community on multisensory flavor quality is revealed here. Revealing the fermentation core microbiome and related enzymes provides important guidance for the development of flavor-enhancement strategies and related genetically engineered bacteria.     

Pre-Deoxidation of Layered Ni-Rich Cathodes to Construct a Stable Interface with Electrolyte for Long Cycling Life

Ni-rich layered oxides as the cathode materials of high-energy-density lithium-ion batteries (LIBs) suffer from capacity decay and structural instability owing to oxygen loss during cycling. It is a huge challenge to prevent the oxygen loss of Ni-rich cathode materials during long cycling. Here, a pre-deoxidation of LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) single crystal materials is achieved by heat treatment at elevated temperatures in argon condition to form a stable surface with rock salt structure. The stable surface structure with oxygen vacancy defects successfully suppresses the harmful phase transitions of NCM811 and effectively improves the stability of the NCM811/electrolyte interface during cycling at a high cut-off voltage. In addition, the intragranular structural evolution and cation mixing degree is inhibited to effectively suppress the intergranular cracking and particle pulverization of cathode during long cycling. The pre-deoxidation of NCM811 exhibits 70.6% capacity retention after 1000 cycles at the current density of 0.5 C between 2.8 and 4.3 V, which is much larger than that of pristine NCM811 capacity retention of 27.3%. The strategy of pre-deoxidation of Ni-rich layered structure cathode to regulate the defect chemistry and surface structure provides a facile and effective way to achieve long cycling life high-energy density LIBs.     

A Laser-Processed Carbon-Titanium Carbide Heterostructure Electrode for High-Frequency Micro-Supercapacitors

Micro-supercapacitors (MSCs) are an important energy storage component for future miniaturized electronic systems, yet their key performance indexes such as high-frequency response, energy density, and cycle life still have a large room to be improved. Herein, a laser-processed carbon-titanium carbide heterostructure (LCTH) electrode is demonstrated, which can excellently address the above key challenges by employing a unique one-step laser-processing fabrication method. Different from the other reported electrode structures, this LCTH electrode shows a heterogeneous structure, featuring the carbon nanofoam layer which provides extremely short ion transport channels and abundant electrochemical active sites, and the underlying titanium carbide layer which can provide excellent electron conductivity and contribute to the pseudo-capacitance. The assembled symmetric supercapacitor can stably work at the voltage window of 3.5 V at an ultra-high frequency of approximately 1121.3 Hz, exhibiting an ultra-high areal specific energy density of 721 µFV² cm⁻² at 120 Hz and a cycle life of 140 000 cycles with capacitance retention of 100.95%, which is superior to most reported MSCs. The as-fabricated MSC is compatible with the contemporary embedded electronic component fabrication processes, which shows significant advantages in large-scale fabrication and system integration, demonstrating a broad prospect for future system-in-package applications.