Latest ArticlesAn array of pyridine-ester enolate based organoboron complexes has been designed and synthesized via a one-pot cascade of Pd-catalyzed α-arylation and BF2 complexation. The rapid structure-activity relationship (SAR) studies indicated that unsymmetrical N,O-chelated BF2 complexes were highly fluorescent in solid state, and exhibited large Stokes shifts, excellent photostability, along with insensitivity to pH. The α-aryl group could not only modulate the electronic effect but also inhibit the intermolecular π-π stacking to promote the aggregation-induced emission (AIE) effect. DFT calculations and experiments identified that the intramolecular charge transfer properties of these N,O-chelates could be switched by the modification of substituents, resulting tunable fluorescence wavelengths. Furthermore, post-complexation modification was accomplished, including Suzuki-Miyaura cross-coupling, Buchwald-Hartwig amination, oxidative cleavage, along with a unique triple substitution reaction involving propargyl Grignard reagents. The exemplificative application of dimethylamine substituted boron complex as a reversible acidic vapor sensor was also demonstrated.
Acidification of paper-based relics is a common problem, leading to their degradation and eventual loss. Paper deacidification is highly dependent on a limited variety of alkaline materials, and the development of new materials that are safe, efficient and easy-to-prepare is highly demanded to ensure a high level of safety and effective protection of paper-based relic. This study proposes the introduction of layered double hydroxide (LDH) and its calcined product, mixed metal oxide (layered double oxide (LDO)), as innovative protective materials for the deacidification of paper with varying levels of acidity. The results demonstrate that treatment with Mg-Al LDH/LDO can effectively modify the pH of acidic paper (e.g., pH ~ 4.0–6.4) to a neutral or weakly basic state, maintaining this desirable pH range even under long-term accelerated aging condition. Remarkably, LDH proves to be well-suited for the protection of slightly acidified paper (e.g., pH > 5.5), while LDO serves as an especially option for the deacidification of severely acidified paper (e.g., pH ≤ 5.5). During aqueous deacidification, due to the memory effect of the LDH-based materials, LDO is converted to rehydrated LDH, which creates a mild and appropriate alkaline retention in the paper, avoiding damage caused by strong alkalinity such as cellulose degradation and pigment fading during subsequent long-term natural preservation of the paper. Furthermore, Mg-Al LDH/LDO materials also exhibit flame-retardant and bacteriostatic properties. This opens up opportunities for the safe, efficient and multifunctional protection of acidified paper-based relics.
Climate change is an important issue facing the world today and carbon reduction has become the focus of attention for all countries. Alternative bio-fuels are an important means to achieve carbon emission reduction. The production of jet fuel precursors from biomass by hydrothermal liquefaction (HTL) has received a lot of attention due to its mild conditions and environmental friendliness. Lignocellulosic biomass and algal biomass are considered as the second and the third generation biomasses as promising raw materials for alternative fuel preparation. Among them, lignocellulosic biomass has been extensively studied due to its wide range of sources and can be divided into one-step HTL and stepwise HTL according to the process method. Algal biomass has been extensively studied experimentally due to its short growth cycle and the fact that it can sequester large amounts of carbon without taking up arable land. In this paper, the feedstock composition of different biomasses is reviewed for the HTL of biomass. A detailed review of the process characteristics, reaction pathways and influencing factors for the HTL production of jet fuel precursors from lignocellulosic biomass and algal biomass is also presented. Theoretical references are provided for further process optimization and bio-crude quality upgrading.
There is increasing evidence shows that either electrical stimulation (ES) or metal ion is an effective way to accelerate ulcerative wound healing. However, less attention is paid to investigating the synergistic effect between them. Herein, we explore the combined effects of ES and multiple metal ions on diabetic wound healing assisted by a triboelectric nanogenerator (TENG). Firstly, the novel Eggshell@CuFe2O4 nanocomposites (NCs) are prepared, which show unique structure and intrinsic antimicrobial properties. Subsequently, the as-prepared nanocomposites are embedded in oxidized starch hydrogel to form a multifunctional composite gel, which is further assembled into a wearable ionic triboelectric nanogenerator (iTENG) patch with polydimethylsiloxane (PDMS). It can convert the mechanical energy produced by a human body motion to electric energy and mediate the sequential release of metal ions (Fe2+/Ca2+/Cu2+), thereby resulting in the "cocktail effect" on impaired tissue. Under their effects, a satisfying healing result in diabetic mouse is identified, which can effectively accelerate wound healing process by relieving inflammation, promoting angiogenesis and collagen deposition. The work puts forward the cocktail effect of electric simulation coupled with the multiple metal ions, and opens up a new perspective in designing iTENG patch towards repair of hard-to-heal wounds.
Bladder cancer is a common malignant tumor of the urinary system with the potential to be treated by nano drug delivery system. The current work describes the synthesis and characterization of a novel nanomaterial to construct a nano-carrier based on 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphatecholine (POPC) loaded doxorubicin (DOX) and embedded with gold nanoparticles and poly(N-isopropyl acrylamide) (PNIPAM) (GNPS@PNIPAM-POPC-DOX, GPPD). The dual-sensitive nanosystem gives simultaneous photothermal treatment and chemotherapy for bladder cancer. In vitro and in vivo properties were assessed using bladder cancer cell lines and mice and GPPD system distribution, tumor inhibition, and biocompatibility are reported. The system had favorable stability, low biological toxicity, controlled release efficiency, photothermal synergistic action, efficient photothermal transition, and favorable tumor suppressive effects. As a result, GPPD is a potential therapeutic approach for bladder cancer.
Oxidative therapies receive a limited antitumor efficiency due to the insufficient reactive oxygen species (ROS) levels at focal sites and the evolvement of antioxidant defense systems. Herein, we develop an albumin-based nanomedicine to co-deliver chlorin e6 (Ce6) and COH-SR4 (CS), which can simultaneously enhance the yield and lethality of intracellular ROS for amplified photodynamic therapy (PDT). In which, CS acts as both an activator of AMP-activated protein kinase (AMPK) and an inhibitor of glutathione S-transferases (GSTs). Benefiting from it, the prepared HSA-Ce6@COH-SR4 (HCCS) enables positive feedback uptake by promoting AMPK phosphorylation, leading to rapid and extensive tumor accumulation of drugs. As a result, HCCS obviously increases the ROS production to elevate intracellular oxidative stress. Furthermore, HCCS can inhibit GSTs to disturb the antioxidant defense system of tumor cells, intensifying the oxidative damage of ROS. Ultimately, the PDT of HCCS is significantly strengthened by improving the ROS yield and lethality, which greatly declines the proliferation of breast cancer in vivo. This study may open a window in the development of drug co-delivery system for enhanced oxidative therapy of tumors.
Satisfactory ionic conductivity, excellent mechanical stability, and high-temperature resistance are the prerequisites for the safe application of solid polymer electrolytes (SPEs) in all-solid-state lithium metal batteries (ASSLMBs). In this study, a novel poly(m-phenylene isophthalamide) (PMIA)-core/poly(ethylene oxide) (PEO)-shell nanofiber membrane and the functional Li6.4La3Zr1.4Ta0.6O12 (LLZTO) ceramic nanoparticle are simultaneously introduced into the PEO-based SPEs to prepare composite polymer electrolytes (CPEs). The core PMIA layer of composite nanofibers can greatly improve the mechanical strength and thermal stability of the CPEs, while the shell PEO layer can provide the 3D continuous transport channels for lithium ions. In addition, the introduction of functional LLZTO nanoparticle not only reduces the crystallinity of PEO, but also promotes the dissociation of lithium salts and releases more Li+ ions through its interaction with the Lewis acid-base of anions, thereby overall improving the transport of lithium ions. Consequently, the optimized CPEs present high ionic conductivity of 1.38×10−4 S/cm at 30 ℃, significantly improved mechanical strength (8.5 MPa), remarkable thermal stability (without obvious shrinkage at 150 ℃), and conspicuous Li dendrites blocking ability (> 1800 h). The CPEs also both have good compatibility and cyclic stability with LiFePO4 (> 2000 cycles) and high-voltage LiNi0.8Mn0.1Co0.1O2 (NMC811) (> 500 cycles) cathodes. In addition, even at low temperature (40 ℃), the assembled LiFePO4/CPEs/Li battery still can cycle stably. The novel design can provide an effective way to exploit high-performance solid-state electrolytes.
Catalyst with high performance has drawn increasing attention recently due to its significant advantages in chemical reactions such as speeding up the reaction, lowering the reaction temperature or pressure, and proceeding without itself being consumed. Despite the superior catalytic performance of precious metal catalysts, transition metal oxides offer a promising route for substitution of precious metals in catalysis arising from their low cost, intrinsic activity and sufficient stability. Mullite-type oxide SmMn2O5 exhibits a unique crystal structure containing double crystalline fields, and nowadays is used widely as the catalyst in different chemical reactions, including the reactions of vehicle emissions reduction and oxygen evolution reaction, gas sensors, and metal-air batteries, promoting attention in catalytic performance enhancement. To our knowledge, there is no review article covering the comprehensive information of SmMn2O5 and its applications. Here we review the recent progress in understanding of the crystal structure of SmMn2O5 and its basic physical properties. We then summarize the catalytic sources of SmMn2O5 and reaction mechanisms, while the strategies to improve catalytic performance of SmMn2O5 are further presented. Finally, we provide a perspective on how to make further progress in catalytic applications.
Hexokinase 2 (HK2) is the rate-limiting enzyme in the first step of glycolysis, catalyzing glucose to glucose-6-phosphate, and overexpressed in most cancer cells. HK2 also binds to voltage-dependent anion channel (VDAC) to stabilize the mitochondrial outer membrane, which inhibits cancer cell apoptosis. Therefore, HK2 has become a potential target for cancer treatment. Proteolysis targeting chimeras (PROTACs) are hetero-bifunctional molecules that recruit an E3 ubiquitin ligase to a given substrate protein resulting in its targeted degradation. Many potent and specific PROTACs targeting dissimilar targets have been developed. In this study, an HK2 PROTAC, 4H-5P-M, was developed and induced the degradation of HK2 relying on the ubiquitin-proteasome system. It was found that 4H-5P-M as an effective HK2 degrader induced HK2 degradation in a dose- and time-dependent manner and suppressed the growth of SW480 cells. 4H-5P-M selectively induced HK2 degradation at a lower concentration than other hexokinase isozymes. Moreover, it could suppress glycolysis and accelerate the apoptosis of cancer cells. Therefore, it provided a new insight into the development of anti-tumor drugs.