Rational synthesis of methylsilsesquioxane aerogels addressing thermal load and compression recovery issues in Li-ion batteries.

Li-ion batteries suffer from two key safety issues: thermal overload and compression recovery, which may lead to flammability and mechanical failure. Silica aerogels are promising solutions to both these issues owing to their excellent thermal stability and tailored mechanical properties. However, finding the optimum sol composition in sol-gel-based aerogel synthesis is needed to address these issues at industry-relevant scales. Here, we propose an innovative approach to determine the optimum sol composition for methylsilsesquioxane (MSQ) aerogel sheets, which is based on the mechanisms of the effects of molar ratios of hydrolysis water and isopropyl alcohol (IPA) to methyltrimethoxysilane (MTMS) on the physical properties of MSQ aerogel sheets and according to the ternary contour distribution of their properties. The synthesized MSQ aerogels exhibited a soft, light, and powderless texture and featured superhydrophobic properties (150.2°), low thermal conductivity of 33.6 mW/(m·K), high thermal stability temperature in nitrogen atmosphere at 479.3 °C and moderate short-term (<6 h) service temperature of 120.0 °C. Significantly, the structural stability and elasticity of the aerogels surpassed the current state-of-the-art, showing recovery to 81.3 % of the original thickness and 85.2 % of the original stress after being subjected to 400 cycles of high-speed and high-strain consecutive compression, respectively. These excellent properties make the MSQ aerogel sheets promising for applications in thermal load and compression recovery management of diverse energy storage devices, including batteries for next-generation electric vehicles.

Degradation of Stains from Metal Surfaces Using a DBD Plasma Microreactor.

The surface cleaning of metals plays a pivotal role in ensuring their overall performance and functionality. Dielectric barrier discharge (DBD) plasma, due to its unique properties, has been considered to be a good alternative to traditional cleaning methods. The confinement of DBD plasma in microreactors brings additional benefits, including excellent stability at high pressures, enhanced density of reactive species, reduced safety risks, and less gas and energy consumption. In the present work, we demonstrated a DBD plasma-based method for the degradation of stains from metal surfaces in a microreactor. Aluminum plates with capsanthin stains were used to investigate the influence of operational parameters on the decolorization efficiency, including plasma discharge power, plasma processing time, and O2 content in the atmosphere. The results revealed that an increase in plasma discharge power and plasma processing time together with an appropriate amount of O2 in the atmosphere promote the degradation of capsanthin stains. The optimum processing condition was determined to be the following: plasma power of 11.3 W, processing time of 3 min, and Ar/O2 flow rate of 48/2 sccm. The evolution of composition, morphology, bonding configuration, and wettability of aluminum plates with capsanthin and lycopene stains before and after plasma treatment were systematically investigated, indicating DBD plasma can efficiently degrade stains from the surface of metals without damage. On this basis, the DBD plasma cleaning approach was extended to degrade rhodamine B and malachite green stains from different metals, suggesting it has good versatility. Our work provides a simple, efficient, and solvent-free approach for the surface cleaning of metals.

High-Responsivity and Broadband MoS2 Photodetector Using Interfacial Engineering.

Combining MoS2 with mature silicon technology is an effective method for preparing high-performance photodetectors. However, the previously studied MoS2/silicon-based heterojunction photodetectors cannot simultaneously demonstrate high responsivity, a fast response time, and broad spectral detection. We constructed a broad spectral n-type MoS2/p-type silicon-based heterojunction photodetector. The SiO2 dielectric layer on the silicon substrate was pretreated with soft plasma to change its thickness and surface state. The pretreated SiO2 dielectric layer and the silicon substrate constitute a multilayer heterostructure with a high carrier concentration and responsiveness. Taking silicon-based and n-type MoS2 heterojunction photodetectors as examples, its responsivity can reach 4.05 × 104 A W1- at 637 nm wavelength with a power density of 2 µW mm-2, and the detectable spectral range is measured from 447 to 1600 nm. This pretreated substrate was proven applicable to other n-type TMDCs, such as MoTe2, ReS2, etc., with certain versatility.

High-Performance Methylsilsesquioxane Aerogels: Hydrolysis Mechanisms and Maximizing Compression Properties.

Synthesis of methylsilsesquioxane aerogels by ambient pressure drying instead of supercritical drying has recently emerged as a major trend, but the issues of low mechanical strength and unstable performance still need to be resolved. This work reveals the microscopic formation mechanisms of gel skeleton based on the kinetic characteristics of methyltrimethoxysilane (MTMS) precursor hydrolysis and the associated sol-gel reactions. The effects of oxalic acid concentration (cOA) and hydrolysis time of MTMS solution (th) on the gelation time, morphologies, microstructures, chemical structure, and compression properties of the as-synthesized methylsilsesquioxane aerogels are investigated. The optimal cOA and th are 38.4 mmol/L and 120 min, respectively, endowing the methylsilsesquioxane aerogels with a compression strength of 0.170 MPa and a maximum compression strain of 61.2%. Precise control of the hydrolysis conditions ensures the formation of branched particle-to-particle networks, which is crucial for maximizing the compression properties of methylsilsesquioxane aerogels synthesized under industry-relevant conditions.

High-performance multilayer WSe2/SnS2p-n heterojunction photodetectors by two step confined space chemical vapor deposition.

Two-dimensional (2D) p-n heterojunctions have attracted great attention due to their outstanding properties in electronic and optoelectronic devices, especially in photodetectors. Various types of heterojunctions have been constituted by mechanical exfoliation and stacking. However, achieving controlled growth of heterojunction structures remains a tremendous challenge. Here, we employed a two-step KI-assisted confined-space chemical vapor deposition method to prepare multilayer WSe2/SnS2p-n heterojunctions. Optical characterization results revealed that the prepared WSe2/SnS2vertical heterostructures have clear interfaces as well as vertical heterostructures. The electrical and optoelectronic properties were investigated by constructing the corresponding heterojunction devices, which exhibited good rectification characteristics and obtained a high detectivity of 7.85 × 1012Jones and a photoresponse of 227.3 A W-1under visible light irradiation, as well as a fast rise/fall time of 166/440µs. These remarkable performances are likely attributed to the ultra-low dark current generated in the depletion region at the junction and the high direct tunneling current during illumination. This work demonstrates the value of multilayer WSe2/SnS2heterojunctions for applications in high-performance photodetectors.

Passivation Effect of the Chlorinated Paraffin Added in the Cutting Fluid on the Surface Corrosion Resistance of the Stainless Steel.

Cutting fluids are the most effective method to lower the cutting temperature and decrease the cutting tool wear. At the same time, the cutting fluids influence the corrosion resistance property of the machined surface. In this study, chlorinated paraffin (CP), which is a common additive in the cutting fluid, was selected as the research objective to study its corrosion resistance property. The passivation effect of CP with different concentrations on the machined surface of stainless steel was studied. Electrochemical measurements and surface morphology investigation were used to characterize the passivation effect of CP with different concentrations. The test results showed that the corrosion resistance of stainless steel in the cutting fluid was enhanced with the increase in CP additive. This reason is that the charge transfer resistance increases and the corrosion current density decreases with the increase in CP additive. The X-ray photoelectron spectroscopy (XPS) results show that the proportion of metal oxides on the processed surface of the stainless steel sample was increased from 20.4% to 22.0%, 32.9%, 26.6%, and 31.1% after adding 1 mL, 2 mL, 4 mL and 6 mL CP in the cutting fluid with a total volume of 500 mL, respectively. The oxidation reaction between CP and the stainless steel sample resulted in an increase in metal oxides proportion, which prevented the stainless steel sample from corrosion in cutting fluid.

Research on antioxidant performance of diglucosyl gallic acid and its application in emulsion cosmetics.

OBJECTIVE: Diglucosyl gallic acid is a whitening active with powerful whitening function. When it acts on human skin, microorganisms on the skin surface and part of the stratum corneum produce α-glucosidase to sever the glucose bond of diglucosyl gallic acid, thereby converting part of diglucosyl gallic acid into gallic acid, acting on the skin and exerting the excellent effects of diglucosyl gallic acid and gallic acid at the same time. Diglucosyl gallic acid has high stability and water solubility, it can reduce free radical generation, inhibit tyrosinase generation, prevent melanin transfer, and control skin inflammation. The present study investigates the in vitro tyrosinase inhibition activity, antioxidant capacity of diglucosyl gallic acid as well as its clinical efficacy as a cosmetic ingredient. METHODS: Taking VC and gallic acid as controls, the pH = 6.8, 0.05 mmol/L Na2HPO4-NaH2PO4 buffer solution was prepared to test the tyrosinase inhibitory activity and antioxidant capacity of diglucosyl gallic acid respectively. Using arbutin and nicotinamide, two common cosmetic raw materials as controls, 20 volunteers (aged 20-35 years old) were selected for the test. (2 ± 0.1) mg/cm2 take the lotion to be tested and apply it to the test part evenly, twice a day, volunteers are not allowed to use sunscreen or other sunscreen products during the study period. RESULTS: The results show that diglucosyl gallic acid has a stronger ability to inhibit the activity of tyrosinase compared with VC, and its IC50 value is 2.68 mg/ mL. Their potential antioxidant activities are further evaluated by the DPPH (α, α-diphenyl-ß-picrylhydrazyl) method and the ABTS [2,2´-azinobis-(3-ethylbenz othiazoline-6-sulphonate)] radical cation (ABTS+) method, in which the gallic acid demonstrates a better performance than the traditional antioxidant vitamin C (VC), while the diglucosyl gallic acid shows poorer performance. As to the reducing ability, VC has the best performance, much better than gallic acid and diglucosyl gallic acid. Furthermore, through clinical experiments, it is shown the application of the diglucosyl gallic acid as a cosmetic ingredient can considerably improve the brightness of the skin and meanwhile reduce the area of ultraviolet spots, melanin and erythema over time. CONCLUSION: The above in vitro and in vivo studies on diglucosyl gallic provide the basis for its future application development in cosmetics.

OBJECTIF: L'acide diglucosyl gallique est un actif blanchissant doté d'une puissante fonction blanchissante. Lorsqu'il agit sur la peau humaine, les microorganismes à la surface de la peau et une partie de la couche cornée produisent de l'α-glucosidase pour rompre la liaison glucose de l'acide diglucosyl gallique, convertissant ainsi une partie de l'acide diglucosyl gallique en acide gallique, agissant sur la peau et exerçant les excellents effets de l'acide diglucosyl gallique et de l'acide gallique en même temps. L'acide diglucosyl gallique a une stabilité et une solubilité dans l'eau élevées, il peut réduire la génération de radicaux libres, inhiber la génération de tyrosinase, empêcher le transfert de mélanine et contrôler l'inflammation cutanée. La présente étude examine l'activité d'inhibition de la tyrosinase in vitro, la capacité antioxydante de l'acide diglucosyl gallique ainsi que son efficacité clinique en tant qu'ingrédient cosmétique. MÉTHODE: En prenant VC (vitamine C) et l'acide gallique comme témoins, la solution tampon pH = 6,8, 0,05 mmol / L Na2HPO4-NaH2PO4 a été préparée pour tester respectivement l'activité inhibitrice de la tyrosinase et la capacité antioxydante de l'acide diglucosyl gallique. En utilisant l'arbutine et le nicotinamide, deux matières premières cosmétiques courantes comme témoins, 20 volontaires (âgés de 20 à 35 ans) ont été sélectionnés pour le test. Prendre la lotion à tester et l'appliquer (2 ± 0,1) mg/cm2 uniformément sur la partie testée, deux fois par jour, les volontaires ne sont pas autorisés à utiliser de crème solaire ou d'autres produits de protection solaire pendant la période d'étude. RÉSULTATS: Les résultats montrent que l'acide diglucosyl gallique a une capacité plus forte à inhiber l'activité de la tyrosinase par rapport au VC, et sa valeur IC50 est de 2,68 mg/mL. Leurs activités antioxydantes potentielles sont ensuite évaluées par la méthode DPPH (α, α-diphényl-ß-picrylhydrazyl) et la méthode ABTS [2,2´-azinobis-(3-ethylbenzothiazoline-6-sulfonate)] radical cation (ABTS+), dans laquelle l'acide gallique présente de meilleures performances que la vitamine C (VC) antioxydante traditionnelle, tandis que l'acide diglucosyl gallique présente de moins bonnes performances. Quant au pouvoir réducteur, la VC a les meilleures performances, bien meilleures que l'acide gallique et l'acide diglucosyl gallique. De plus, à travers des expériences cliniques, il est démontré que l'application de l'acide diglucosyl gallique en tant qu'ingrédient cosmétique peut considérablement améliorer la luminosité de la peau et réduire en même temps la surface des taches de soleil, de la mélanine et de l'érythème au fil du temps. CONCLUSION: Les études in vitro et in vivo ci-dessus sur le diglucosyl gallique constituent la base de son futur développement d'applications en cosmétique.

Inflammation-Associated Senescence Promotes Helicobacter pylori-Induced Atrophic Gastritis.

BACKGROUND & AIMS: The association between cellular senescence and Helicobacter pylori-induced atrophic gastritis is not clear. Here, we explore the role of cellular senescence in H pylori-induced atrophic gastritis and the underlying mechanism. METHODS: C57BL/6J mice were infected with H pylori for biological and mechanistic studies in vivo. Gastric precancerous lesions from patients and mouse models were collected and analyzed using senescence-associated beta-galactosidase, Sudan Black B, and immunohistochemical staining to analyze senescent cells, signaling pathways, and H pylori infection. Chromatin immunoprecipitation, luciferase reporter assays, and other techniques were used to explore the underlying mechanism in vitro. RESULTS: Gastric mucosa atrophy was highly associated with cellular senescence. H pylori promoted gastric epithelial cell senescence in vitro and in vivo in a manner that depended on C-X-C motif chemokine receptor 2 (CXCR2) signaling. Interestingly, H pylori infection not only up-regulated the expression of CXCR2 ligands, C-X-C motif chemokine ligands 1 and 8, but also transcriptionally up-regulated the expression of CXCR2 via the nuclear factor-κB subunit 1 directly. In addition, CXCR2 formed a positive feedback loop with p53 to continually enhance senescence. Pharmaceutical inhibition of CXCR2 in an H pylori-infected mouse model attenuated mucosal senescence and atrophy, and delayed further precancerous lesion progression. CONCLUSIONS: Our study showed a new mechanism of H pylori-induced atrophic gastritis through CXCR2-mediated cellular senescence. Inhibition of CXCR2 signaling is suggested as a potential preventive therapy for targeting H pylori-induced atrophic gastritis. GEO data set accession numbers: GSE47797 and GSE3556.