The interface electrochemical and chemical mechanism of a low alloy steel in a 3.5% NaCl solution containing Ce3+-based inhibitor

The interface electrochemical and chemical mechanism of the low alloy steel in a 3.5% NaCl solution containing the Ce3+-based inhibitor was investigated by the electrochemical techniques in conjunction with the surface analysis technologies. It was shown that the Ce(3+-)based inhibitor was an anodic inhibitor with more than 90.0% inhibitory efficiency. The net-shaped inhibiting film with 200 to 500-nm greyish balls was observed on the specimen surface. During the corrosion reaction occurred on the surface of the low alloy steel, the hydrolysis reaction of P3O105- and the disproportionation reaction of Ce3+ ions simultaneously occurred, too, resulting in the formation of the net-shaped inhibiting film with nano-scale greyish ball-type products, which contained Ce element and had an obvious effect on the electrochemical process of the low alloy steel in a 3.5% NaCl solution containing the Ce3+-based inhibitor. Therefore, the EIS spectra of the low alloy steel in a 3.5% NaCl solution containing the Ce3+-based inhibitor were composed of a capacitive loop at a high-frequency region and an inductive impedance loop at a low-frequency region. The charge-transfer resistance (R-t) increased with the immersion elapsed time, indicating that the inhibition efficiency of the Ce3+-based inhibitor increased with immersion elapsed time. The calculated data based on the fitted electrochemical parameters showed the partial coverage of the inhibitor. This was further revealed by the analysis of electrochemical kinetics that the inductive impedance (L) loop at a low frequency region resulted from the localized absorption of the Ce3+-based inhibitor on the surface of the low alloy steel in a 3.5% NaCl solution. It was also verified by micro-morphologies

Suppression of the RAC1/MLK3/p38 Signaling Pathway by β-Elemene Alleviates Sepsis-Associated Encephalopathy in Mice

It is still difficult to treat sepsis-associated encephalopathy (SAE) which is a diffuse brain dysfunction caused by sepsis, with excessive activation of microglia as one of the main mechanisms. Ras-related C3 botulinum toxin substrate 1 (RAC1) is proven to be a key molecule in the inflammatory signaling network. By using microglial cell line BV-2 and a mouse model of cecal ligation puncture (CLP), we herein evaluated the effects of β-elemene, an extract of Curcuma zedoaria Rosc., on RAC1 signaling in microglia. β-Elemene decreased the expressions of pro-inflammatory cytokines [tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6] and attenuated translocation of nuclear factor-κB (NF-κB) p65 from the cytosol to the nucleus in BV-2 cells after lipopolysaccharide (LPS) treatment. It also inhibited the activation of RAC1, mixed-lineage protein kinase 3 (MLK3) and p38 mitogen-activated protein kinase (MAPK). The phosphorylation of the RAC1 Ser71 site was increased by β-elemene. Moreover, the learning and memory abilities of CLP mice in the water maze test and fear conditioning test were improved after β-elemene treatment. It reduced the expression of the microglial marker IBA1, significantly increased RAC1 Ser71 phosphorylation, and suppressed the RAC1/MLK3/p38 signaling activation and inflammatory response in the hippocampus. In conclusion, β-elemene effectively alleviated SAE in mice and inhibited the RAC1/MLK3/p38 signaling pathway in microglia, and might be an eligible potential candidate for SAE treatment

Organic NIR-II dyes with ultralong circulation persistence for image-guided delivery and therapy

Acknowledgments This work was partially supported by grants from the National Key R&D Program of China (2020YFA0908800), NSFC (82111530209, 81773674, 91959103, 81573383, 21763002), Shenzhen Science and Technology Research Grant (JCYJ20190808152019182), the Applied Basic Research Program of Wuhan Municipal Bureau of Science and Technology (2019020701011429), Hubei Province Scientific and Technical Innovation Key Project (2020BAB058), the Local Development Funds of Science and Technology Department of Tibet (XZ202102YD0033C, XZ202001YD0028C), and the Fundamental Research Funds for the Central Universities.Peer reviewedPublisher PD

Research and Development of Zincoborates: Crystal Growth, Structural Chemistry and Physicochemical Properties

Borates have been regarded as a rich source of functional materials due to their diverse structures and wide applications. Therein, zincobrates have aroused intensive interest owing to the effective structural and functional regulation effects of the strong-bonded zinc cations. In recent decades, numerous zincoborates with special crystal structures were obtained, such as Cs3Zn6B9O21 and AZn2BO3X2 (A = Na, K, Rb, NH4; X = Cl, Br) series with KBe2BO3F2-type layered structures were designed via substituting Be with Zn atoms, providing a feasible strategy to design promising non-linear optical materials; KZnB3O6 and Ba4Na2Zn4(B3O6)2(B12O24) with novel edge-sharing [BO4]5− tetrahedra were obtained under atmospheric pressure conditions, indicating that extreme conditions such as high pressure are not essential to obtain edge-sharing [BO4]5−-containing borates; Ba4K2Zn5(B3O6)3(B9O19) and Ba2KZn3(B3O6)(B6O13) comprise two kinds of isolated polyborate anionic groups in one borate structure, which is rarely found in borates. Besides, many zincoborates emerged with particular physicochemical properties; for instance, Bi2ZnOB2O6 and BaZnBO3F are promising non-linear optical (NLO) materials; Zn4B6O13 and KZnB3O6 possess anomalous thermal expansion properties, etc. In this review, the synthesis, crystal structure features and properties of representative zincoborates are summarized, which could provide significant guidance for the exploration and design of new zincoborates with special structures and excellent performance

Inhibition on α-Glucosidase Activity and Non-Enzymatic Glycation by an Anti-Oxidative Proteoglycan from Ganoderma lucidum

The prevention of postprandial hyperglycemia and diabetic complications is crucial for diabetes management. Inhibition of α-glucosidase to slow carbohydrate metabolism is a strategy to alleviate postprandial hyperglycemia. In addition, suppression of non-enzymatic glycation can diminish the advanced glycation end products and reduce the oxidative stress and inflammation, thereby preventing the diabetic complications. In this study, an anti-oxidative proteoglycan (named FYGL) extracted from Ganoderma lucidum was investigated in vitro for its inhibitory effect on α-glucosidase and non-enzymatic glycation using molecular kinetics, intrinsic fluorescence assay, and bovine serum albumin glycation models. The molecular kinetics and fluorescence assay revealed that FYGL decreases α-glucosidase activity by forming a FYGL–α-glucosidase complex. To evaluate the anti-glycation effect, fructose-glycated and methylglyoxal-glycated BSA models were analyzed by spectroscopic and SDS-PAGE methods. Results showed that FYGL inhibited the glycation at every stage and suppressed glycoxidation, possibly due to its anti-oxidative capacity and FYGL–BSA complex formation. Furthermore, we demonstrated in vivo that FYGL could alleviate postprandial hyperglycemia in db/db mice as well as AGE accumulation and vascular injury in diabetic rats. Overall, FYGL possesses anti-postprandial hyperglycemia and anti-glycation functions and would be potentially used in clinic for diabetes and related complication management

Effects of the Orientation of [B₅O₁₁]^7– Fundamental Building Blocks on Layered Structures Based on the Pentaborates

Four new layered pentaborates Rb₄Ba_2.5­B₂₀O₃₄­Br, Rb₂Ba₄­B₂₀O₃₄­Br₂, Rb₄Ba_2.5­B₂₀O₃₄­Cl, and KBa­B₅O₉ have been successfully synthesized via a high-temperature solution method; the former three are the first series of compounds reported in the Rb-Ba-B-O-X (X = halogen) system. Interestingly, the structures of the above compounds are composed of the same [B₅­O₁₁]^7– fundamental building block (FBB), which could be further linked to form ²_∞[B₁₀­O₁₇]^4– double layers for the former three compounds and ²_∞[B₅­O₉]^3– single layers for the last one. The structure comparisons among all the available anhydrous pentaborates reveal that the structures of the anionic framework are affected by the relationship between the orientation of [B₅­O₁₁]^7– FBB axes and the layer plane (parallel or perpendicular), which will produce the different number of terminal O atoms in the initial pentaborate blocks. The viewpoints give us a feasible way to investigate the layered structures and expand the structural diversity of borates. Furthermore, the infrared spectra, UV–vis–NIR diffuse reflectance spectra, and thermal behaviors of these compounds were also studied