▲ Vol 02 Issue 02 |  April, 2023

Lyotropic liquid crystals of tetradecyldimethylaminoxide in water and the in situ formation of gold nanomaterials

Na Zhang, Aoxue Xu, Baoyong Liu, Nicolas Godbert, Hongguang Li

Lyotropic liquid crystals (LLCs) produced by the self-assembly of surfactant in water represent an important class of highly ordered soft materials that have a wide range of applications. This study investigates the LLCs formed by a zwitterionic surfactant (tetradecyldimethylaminoxide, C14DMAO) in water. The organization of C14DMAO within the LLCs was determined based on a detailed analysis of small-angle X-ray scattering measurements and polarized microscopy observations of a typical sample. Additional to the singe-phase region, which has a hexagonal organization, several two-phase regions were observed, exhibiting the coexistence of hexagonal/cubic, cubic/lamellar, and hexagonal/lamellar phases. The phase behavior showed an obvious dependence on temperature, with more pronounced two-phase regions at lower temperatures. Using the LLCs as a matrix, Au nanospheres, nanoellipsoids, and nanorods were prepared without requiring additional reducing reagents. These three- and one-dimensional Au nanomaterials could be converted to two-dimensional plates via the introduction of a small amount of cationic surfactant to the LLCs, such as cetyltrimethylammonium bromide (CTAB) and 1-hexadecyl-3-methylimidazolium bromide ([C16MIm]B), which showed pronounced surface-enhanced Raman scattering activity towards solid rhodamine. The LLCs loaded with CTAB (or [C16MIm]B) and HAuCl4 exhibited slightly different structures and mechanical strength from the original LLCs, thereby forming a new class of highly crowded colloidal materials.

https://www.sciencedirect.com/science/article/pii/S2772571522000419

▲ Vol 58 Issue 02 | April, 2023

High glucose levels contribute to vascular fibrosis via the activation of the endothelial-to-mesenchymal transition in periodontitis

Yuyang Li, Yue Zhao, Lutong Song, Liping Xiong, Wen Li, Wenlei Wu, Leiying Miao

Objective
To determine the changes of Porphyromonas gingivalis (P. gingivalis) growth and metabolism and identify whether the vascular epithelium change could be induced in diabetic periodontitis.
Background
Maintaining favourable vascular function is a precondition for periodontal regeneration. In diabetic periodontitis, high glucose levels could enhance the metabolism of pathogens, and a complex condition involving inflammation and high glucose levels would disrupt homeostasis of the epithelium and promote fibrosis by endothelial-to-mesenchymal transition (EndMT).
Methods
Porphyromonas gingivalis was cultured with glucose to judge its metabolic activity. Human umbilical vein endothelial cells (HUVECs) were treated with P. gingivalis-lipopolysaccharide (LPS) (10 μg/ml) and/or high glucose concentrations (25 mM), and transforming growth factor (TGF)-β inhibitor was used to block EndMT. Inflammation level was assessed by flow cytometry. Multiple biological functions including EndMT, angiopoiesis, and cell migration were analysed. Additionally, gene expressions and protein levels were determined with qPCR and western blot, respectively. Finally, blood vessels were cultured ex vivo, and EndMT and fibrosis markers were detected by immunohistochemistry.
Results
Glucose could promote P. gingivalis growth and biofilm formation as well as the expression of virulence factor genes including FimA, RgpA, RgpB, and Kgp. P. gingivalis-LPS and glucose could increase intracellular reactive oxygen species (ROS) and promote fibrosis via EndMT in HUVECs, along with attenuating angiopoiesis and cell migration, which could be resumed by blocking EndMT with TGF-β inhibitor. Vascular fibrosis was observed after the addition of glucose via EndMT regulation.
Conclusion
Glucose augmented the growth and metabolism of P. gingivalis and promoted fibrosis by the activation of EndMT, as well as the inhibition of angiopoiesis and cell migration.

https://onlinelibrary.wiley.com/doi/10.1111/jre.13084

▲ Vol 16 Issue 04 | April, 2023

In-plane grain boundary induced defect state in hierarchical NiCo-LDH and effect on battery-type charge storage

Jinjin Ban, Xiaohan Wen, Honghong Lei, Guoqin Cao, Xinhong Liu

Domain boundaries are regarded as the effective active sites for electrochemical energy storage materials due to defects enrichment therein. However, layered double hydroxides (LDHs) tend to grow into single crystalline nano sheets due to their unique two-dimentional (2D) lattice structure. Previously, much efforts were made on the designing hierarchical structure to provide more exposed electroactive sites as well as accelerate the mass transfer. Herein, we demonstrate a strategy to introduce low angle grain boundary (LAGB) in the flakes of Ni/Co layered double hydroxides (NiCo-LDHs). These defect-rich nano flakes were self-assembled into hydrangea-like spheres that further constructed hollow cage structure. Both the formation of hierarchical structure and grain boundaries are interpreted with the synergistic effect of Ni2+/Co2+ ratio in an “etching-growth” process. The domain boundary defect also results in the preferential formation of oxygen vacancy (Vo). Additionally, density functional theory (DFT) calculation reveals that Co substitution is a critical factor for the formation of adjacent lattice defects, which contributes to the formation of domains boundary. The fabricated battery-type Faradaic NiCo-LDH-2 electrode material exhibits significantly enhanced specific capacitance of 899 C·g−1 at a current density of 1 A·g−1. NiCo-LDH-2//AC asymmetric capacitor shows a maximum energy density of 101.1 Wh·kg−1 at the power density of 1.5 kW·kg−1.

https://www.sciopen.com/article/10.1007/s12274-022-4485-1

▲ April, 2023

metalmat创刊号

metalmat

https://mp.weixin.qq.com/s/JMREvOKKQTqnnFGYFISSKw
https://onlinelibrary.wiley.com/journal/29401402

▲ Vol 50 Issue 08 | 04 April, 2023

碳纤维增强复合材料与钛合金激光连接仿真

景若木, 徐洁洁, 肖荣诗, 黄婷

为了研究不同工艺参数对TC4钛合金与连续编织碳纤维增强聚醚醚酮基复合材料（CFPEEK）的激光焊接接头的影响规律，并对焊接工艺窗口进行预测，使用ABAQUS软件建立基于热传导的有限元仿真模型，计算TC4钛合金/CFPEEK激光焊接接头的温度场分布。针对CFPEEK中连续编织碳纤维的实际铺层情况，在建模时对复合材料进行分层处理，将碳纤维层视为正交性质的材料。在此基础上探究了激光功率、焊接速度、光斑尺寸对焊缝熔化深度及宽度的影响规律，计算结果与实际试验结果吻合度较高，激光功率、焊接速度、光斑尺寸等工艺参数均对接头结合处的温度有较大影响。经过多组参数的计算，得到了TC4钛合金/连续编织CFPEEK激光连接的预测工艺窗口。结果表明，所建立的有限元模型能够有效模拟连续编织CFPEEK与TC4钛合金激光连接的温度场分布，对实际试验有一定指导意义，可降低试验成本。

https://www.opticsjournal.net/Articles/OJae65ad6e772d03b4/Abstract

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静远嘲风（MY Scimage） 成立于2007年，嘲风取自中国传统文化中龙生九子，子子不同的传说，嘲风为守护屋脊之瑞兽，喜登高望远；静远取自成语“宁静致远”，登高莫忘初心，远观而不可务远。