Hydrogel Extinguishants.

The exploitation of clean and efficient fire extinguishing materials has substantial implications for improving disaster prevention, mitigation, and relief capabilities, maintaining public safety, and protecting people's lives and property as well as the natural environment. Natural polymer hydrogel with high water containment, excellent film formation, high heat insulation, ecofriendliness, and degradability has huge potential in achieving new breakthroughs for developing clean and efficient fire extinguishing materials and products. In recent years, the exploitation of hydrogel extinguishing materials and the fabrication of products has attracted great attention, gradually replacing traditional fire extinguishing products. In this perspective, an in-depth review of the evolution of hydrogels applied for fire extinguishing and prevention is presented. Firstly, the extinguishing principles of hydrogel extinguishants are explained. Secondly, the preparation strategies and evaluation system of the hydrogel extinguishants are emphatically discussed. Although great progress has been made in developing high-performance hydrogel extinguishants, it remains challenging to develop cost-effective, degradable, and easy-to-use hydrogel extinguishants. Additionally, we highlight the importance of considering the commercial aspects of hydrogel extinguishants. Looking into the future, hydrogel extinguishants are promising, but continued investment in research and development is necessary to overcome the challenges.

MXene-Stabilized VS2 Nanostructures for High-Performance Aqueous Zinc Ion Storage.

Aqueous zinc-ion batteries (AZIBs) based on vanadium oxides or sulfides are promising candidates for large-scale rechargeable energy storage due to their ease of fabrication, low cost, and high safety. However, the commercial application of vanadium-based electrode materials has been hindered by challenging problems such as poor cyclability and low-rate performance. To this regard, sophisticated nanostructure engineering technology is used to adeptly incorporate VS2 nanosheets into the MXene interlayers to create a stable 2D heterogeneous layered structure. The MXene nanosheets exhibit stable interactions with VS2 nanosheets, while intercalation between nanosheets effectively increases the interlayer spacing, further enhancing their stability in AZIBs. Benefiting from the heterogeneous layered structure with high conductivity, excellent electron/ion transport, and abundant reactive sites, the free-standing VS2/Ti3C2Tz composite film can be used as both the cathode and the anode of AZIBs. Specifically, the VS2/Ti3C2Tz cathode presents a high specific capacity of 285 mAh g-1 at 0.2 A g-1. Furthermore, the flexible Zn-metal free in-plane VS2/Ti3C2Tz//MnO2/CNT AZIBs deliver high operation voltage (2.0 V) and impressive long-term cycling stability (with a capacity retention of 97% after 5000 cycles) which outperforms almost all reported Vanadium-based electrodes for AZIBs. The effective modulation of the material structure through nanocomposite engineering effectively enhances the stability of VS2, which shows great potential in Zn2+ storage. This work will hasten and stimulate further development of such composite material in the direction of energy storage.

Promote lipolysis in white adipocytes by magnetic hyperthermia therapy with Fe3O4microsphere-doped hydrogel.

Obesity has become an ongoing global crisis, since it increases the risks of cardiovascular disease, type 2 diabetes, fatty liver, cognitive decline, and some cancers. Adipose tissue is closely associated with the disorder of lipid metabolism. Several efforts have been made toward the modulation of lipid accumulation, but have been hindered by poor efficiency of cellular uptake, low safety, and uncertain effective dosage. Herein, we design an Fe3O4microsphere-doped composite hydrogel (Fe3O4microspheres @chitosan/ß-glycerophosphate/collagen), termed as Fe3O4@Gel, as the magnetocaloric agent for magnetic hyperthermia therapy (MHT), aiming to promote lipolysis in white adipocytes. The experimental results show that the obtained Fe3O4@Gel displays a series of advantages, such as fast sol-gel transition, high biocompatibility, and excellent magneto-thermal performance. MHT, which is realized by Fe3O4@Gel subjected to an alternating magnetic field, leads to reduced lipid accumulation, lower triglyceride content, and increased mitochondrial activity in white adipocytes. This work shows that Fe3O4@Gel-mediated MHT can effectively promote lipolysis in white adipocytesin vitro, which provides a potential approach to treat obesity and associated metabolic disorders.

Aptamer-modified atomically precise gold nanoclusters as targeted nanozymes to scavenge reactive oxygen species in white adipocytes.

Oxidative stress caused by excessive reactive oxygen species (ROS) leads to the dysfunction of white adipocytes and white fat, and also promotes triglyceride storage by inhibiting the respiration of adipocytes directly. Nanozymes, as a new generation of artificial enzymes, have exhibited attractive potential in scavenging ROS and treatment of ROS-related diseases. Herein, aptamer-modified atomically precise gold Au25nanoclusters (Apt-Au25NCs), are employed as targeted nanozymes to scavenge ROS in white adipocytes. Our results show that Apt-Au25NCs have high targeting capability toward white adipocytes with low cytotoxicity. Furthermore, Apt-Au25NCs show high superoxide dismutase (SOD)-like and catalase (CAT)-like activity in a concentration-dependent manner, and also good thermal and pH stability compared with natural SOD and CAT. Finally, the efficiency of ROS scavenging by Apt-Au25NCs in white adipocytes is evaluated. This work demonstrates that Apt-Au25NCs, as targeted nanozymes, are efficient in scavenging ROS in white adipocytes, exhibiting promising potential for the treatment of obesity and related diseases.

Aptamer-functionalized AuNCs nanogel for targeted delivery of docosahexaenoic acid to induce browning of white adipocytes.

Obesity, as a global public health concern, causes a series of metabolic disorders and other diseases. Browning of white fat (white adipocytes transforming to beige adipocytes) offers an attractive approach for obesity treatment. In the present study, aptamer-functionalized nanogel of gold nanoclusters (AuNCs), termed Apt-NG, was developed as the targeted delivery vehicle of browning agent docosahexaenoic acid (DHA). Apt-NG has multiple advantages, including nanoscale size, strong autofluorescence, low toxicity, and excellent targeting capability to white adipocytes. After treatment with DHA@Apt-NG, the morphology of lipid droplets changed evidently; meanwhile the triglyceride level decreased while the mitochondrial activity increased. The DHA@Apt-NG treatment effectively up-regulated the mRNA expression levels of Ucp1, Pgc-1α, Pparg, and Prdm16, which play important roles in browning of white adipocytes. This study provides a feasible strategy to achieve efficient browning of white adipocytes based on targeted delivery nanosystems, inspiring a new idea for obesity treatment.

Aspergichromones A-E, Five Chromone Derivatives with Complicated Polycyclic Architecture from Aspergillus deflectus.

Five unprecedented chromone derivatives involving a 6/6/5/5/5/6 hexacyclic scaffold (1, 2), 6/6/5/6/6/6/6 heptacyclic scaffold (3), and 6/6/6/5/5/6 hexacyclic scaffold (4, 5) were obtained from the fungus Aspergillus deflectus NCC0415. Their structures were identified using comprehensive spectroscopic analysis, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Except for 3, the other compounds, especially the 6/6/6/5/5/6 hexacyclic derivatives (4 and 5), exhibited potent inosine-5'-monophosphate dehydrogenase (IMPDH) inhibitory activities.

New protein tyrosine phosphatase inhibitors from fungus Aspergillus gorakhpurensis F07ZB1707.

Twelve new compounds, aspergorakhins A-L (1-12) coupled with one known xanthone leptosphaerin D (13), were isolated from the extract of soil-derived fungus Aspergillus gorakhpurensis F07ZB1707. Their structures were elucidated by spectroscopic data analysis including UV, IR, NMR, and HRESIMS. The absolute configurations of 5 and 8-11 were identified using ECD and OR calculations. All compounds were tested by enzyme inhibitory activity assay in vitro. Aspergorakhin A (1) showed selective activities against PTP1B and SHP1 over TCPTP with IC50 values 0.57, 1.19, and 22.97 µM, respectively. Compounds 1 and 2 exhibited modest cytotoxicity against tumor cell lines A549, HeLa, Bel-7402, and SMMC-7721 with IC50 values in the range of 6.75-83.4 µM.

Azaphilones with protein tyrosine phosphatase inhibitory activity isolated from the fungus Aspergillus deflectus.

Six undescribed azaphilones, deflectins C1-C3, deflectins D1-D2, and deflectin E, along with five known azaphilones were obtained from a solid culture of the wild fungus Aspergillus deflectus NCC0415. Their structures were determined by HRESIMS, NMR and ECD analyses, together with the GIAO 13C NMR calculation method. All compounds displayed strong or moderate inhibitory activity against protein tyrosine phosphatases SHP2 and PTP1B. Structure-activity relationship analysis of these azaphilones suggested that the length of the ketone aliphatic side chain would affect their SHP2 and PTP1B inhibitory activity. In addition, the presence of a Δ8(12) double bond on γ-lactone ring and the presence of CH3-2' in fatty chains may increase their inhibitory activity.

Discovery of a new structural class of competitive hDHODH inhibitors with in vitro and in vivo anti-inflammatory, immunosuppressive effects.

Human dihydroorotate dehydrogenase (hDHODH) is an inner mitochondrial membrane enzyme that involves in the fourth step of the biosynthesis of pyrimidine base. Inhibitors of hDHODH have been proven efficacy for the treatments of inflammation, rheumatoid arthritis, multiple sclerosis and cancer. In the present study, ascochlorin (ASC) and its derivatives, natural compounds from fungal metabolites, were discovered as hDHODH inhibitors by high-throughput screening. Enzyme kinetics studies showed that ASC competitively binds to hDHODH at the site of coenzyme Q substrate. In ex vivo study, ASC significantly inhibited the ConA-stimulated T lymphocytes proliferation and interleukin-2, interferon-γ production. Furthermore, ASC showed significant in vivo anti-inflammatory and immunosuppressive effects on the mice ears swelling, allogenic skin grafts and rat collagen-induced arthritis animal disease models. ASC significantly reduced ears edema level of mice, increased the survival time of allogenic skin implanted on the mice and attenuated arthritis severity of rat model. In conclusion, ASC was identified as a new structural class of hDHODH inhibitors with efficient anti-inflammatory, immunosuppressive activity, and may be a promising candidate for the development of new therapy in the treatment of autoimmune diseases.

[F01WB-1315 A and B, two dihydroorotate dehydrogenase inhibitors from microbial metabolites].

OBJECTIVE: Dihydroorotate Dehydrogenase (DHODH) catalyzes the rate-limiting step in pyrimidine biosynthesis, and its inhibitors have been developed as drugs for treatment of immune diseases. We studied new DHODH inhibitors from microbial metabolites. METHODS: We established a rapid and effective high throughput screening method for screening DHODH inhibitors from microbial metabolites. The active compounds were isolated from the candidate strain by column chromatography and preparative HPLC. RESULTS: We picked out F01WB-1315 strain as candidate from 4560 fungal strains. We isolated two active compounds F01WB-1315A and B, with IC50 of 0.07 microg/mL and 0.51 microg/mL, respectively. F01WB-1315B could completely inhibit the spleen lymphocytes proliferation stimulated by ConA in vitro, but F01WB-1315A only had 31.62% inhibitory activity. F01WB-1315A, B were identified to be Ascofuranone and Ascochlorin by their physicochemical properties, MS, 13C-NMR and 1H-NMR analysis. CONCLUSION: F01WB-1315A and B are two strong specific DHODH inhibitors and show moderate inhibitory activity against spleen lymphocytes proliferation.