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Preparation of Thermosensitive Hydrogels by means of Tandem Physical and Chemical Crosslinking
Hong-Liang Wei,Kai Yao,Zhe Yang,Hui-Juan Chu,Jing Zhu,Cun-Cai Ma,Zi-Xuan Zhao 한국고분자학회 2011 Macromolecular Research Vol.19 No.3
The tandem physical and chemical crosslinking was used to prepare injectable hydrogels. First, the terpolymers with diene groups were synthesized by the free radical copolymerization of N-isopropylacrylamide (NIPA), N,N-dimethylacrylamide (DMA) and furfuryl methacrylate (FM). Second, dienophile-functionalized terpolymers were obtained from the terpolymers of NIPA, DMA, and 2-hydroxyethyl methacrylate (HEMA) and Nmaleoyl alanine (AMI) by a coupling reaction under N,N'-dicyclohexylcarbodiimide (DCC). When the screened diene-functionalized terpolymer and dienophile-functionalized terpolymer were dissolved separately in water and mixed, physically cross-linked hydrogels formed rapidly within 10 s at 37 ℃. Subsequently, the physically crosslinked hydrogels could change gradually into chemically cross-linked hydrogels by a Diels-Alder reaction and the mechanical strength of the hydrogels could be improved. The swelling behavior study suggests that the hydrogels possess thermosensitivity and good reproducibility at different temperatures. The strategy described, i.e. incorporating the advantages of physically crosslinked hydrogels and chemically crosslinked hydrogels, has potential applications in the preparation of injectable hydrogels.
Ru-Xiang Hua,Hong-Xuan Ma,Wei Zou,Wei Zhang,Zhuo Wang 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.2
Spraying trajectory planning is a key and challenging work for intelligent spraying robot. In order to effectively fulfill spraying on complex surfaces without CAD model, a novel spraying trajectory planning method based on segmentation and trajectory sequence optimization is proposed in this paper, which is mainly composed by three steps: surface segmentation, trajectories generation and trajectories connection. In surface segmentation, a method named regional growth with minimum curvature point (RGMCP) is proposed to segment a 3D entity into different subsurfaces by taking normals and curvatures into consideration simultaneously. In trajectories generation step, an intersection of plane and point cloud (IPPC) algorithm is used to generate the optimal spraying trajectory for each segmented subsurface. Finally, for trajectories connection, a sequence optimization algorithm based on swap-evolution particles (SOSP) is proposed to connect all the subsurface trajectories as a complete spraying one in an optimum manner by regarding it as a sequence optimization problem. The effectiveness of the proposed method is validated by simulation and practical experiment simultaneously. Comparatively, our method can improve the efficiency of a spray task with 367 trajectories and 627 s time-consuming to 215 trajectories and 413 s, while the coating thickness variances are lowered from 51.9 µm2 and 30.4 µm2 to 3.64 µm2 and 7.89 µm2 respectively, which shows that the proposed method is more effective and can keep better coating thickness uniformity.
Zhou Meng-jiao,Yang Jia-jie,Ma Ting-yao,Feng Ge-xuan,Wang Xue-lian,Wang Li-Yong,Ge Yu-ze,Gao Ran,Hong-liang Liu,Shan Lin,Kong Lu,Chen Xiao-hong 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-
MYB-NFIB fusion and NOTCH1 mutation are common hallmark genetic events in salivary gland adenoid cystic carcinoma (SACC). However, abnormal expression of MYB and NOTCH1 is also observed in patients without MYB-NFIB fusion and NOTCH1 mutation. Here, we explore in-depth the molecular mechanisms of lung metastasis through single-cell RNA sequencing (scRNA-seq) and exome target capture sequencing in two SACC patients without MYB-NFIB fusion and NOTCH1 mutation. Twenty-five types of cells in primary and metastatic tissues were identified via Seurat clustering and categorized into four main stages ranging from near-normal to cancer-based on the abundance of each cell cluster in normal tissue. In this context, we identified the Notch signaling pathway enrichment in almost all cancer cells; RNA velocity, trajectory, and sub-clustering analyses were performed to deeply investigate cancer progenitor-like cell clusters in primary tumor-associated lung metastases, and signature genes of progenitor-like cells were enriched in the “MYC_TARGETS_V2” gene set. In vitro, we detected the NICD1-MYB-MYC complex by co-immunoprecipitation (Co-IP) and incidentally identified retinoic acid (RA) as an endogenous antagonist of genes in the “MYC_TARGETS_V2” gene set. Following this, we confirmed that all-trans retinoic acid (ATRA) suppresses the lung metastasis of SACC by correcting erroneous cell differentiation mainly caused by aberrant NOTCH1 or MYB expression. Bioinformatic, RNA-seq, and immunohistochemical (IHC) analyses of primary tissues and metastatic lung tissues from patients with SACC suggested that RA system insufficiency partially promotes lung metastasis. These findings imply the value of the RA system in diagnosis and treatment.