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991.
Multi-bond network(MBN) which contains a single network with hierarchical cross-links is a suggested way to fabricate robust hydrogels. In order to reveal the roles of different cross-links with hierarchical bond energy in the MBN, here we fabricate poly(acrylic acid) physical hydrogels with dual bond network composed of ionic cross-links between carboxylFe3+ interactions and hydrogen bonds, and compare these dually cross-linked hydrogels with singly and ternarily cross-linked hydrogels. Simple models are employed to predict the tensile property, and the results confirm that the multi-bond network with hierarchical distribution in the bond energy of cross-links endows hydrogel with effective energy-dissipating mechanism. Moreover, the dually cross-linked MBN gels exhibit excellent mechanical properties(tensile strength up to 500 k Pa, elongation at break ~ 2400%) and complete self-healing after being kept at 50 °C for 48 h. The factors on promoting self-healing are deeply explored and the dynamic multi-bonds are regarded to trigger the self-healing along with the mutual diffusion of long polymer chains and ferric ions. 相似文献
992.
Shuai Zong Lan Li Jinglei Li Farnaz Shaikh Liu Yang Ming Ye 《Applied biochemistry and biotechnology》2017,182(2):669-686
In the present study, an intracellular melanin, named LIM205, was separated from Lachnum YM205 mycelia and was purified on a Sephadex G-15 column. The molecular weight of LIM205 was determined as 522 Da, and its molecular formula was speculated as C28H14N2O7S. The possible chemical structure of LIM205 was determined according to the results of Fourier transform infrared (FT-IR), 1H NMR, 13C NMR, and pyrolysis/GC-MS analysis. With the aim to increase its water solubility, its carboxymethylated derivative, named CLIM205, was formed by the substitution of hydrogen atoms in LIM205 with one, two, and three carboxymethylate groups. FT-IR, UV, and ESI-MS analysis demonstrated that the carboxymethylate groups were conjugated onto LIM205. The lead detoxification activities of LIM205 and CLIM205 had also been investigated. In vivo test showed that both LIM205 and CLIM205 reduced the tissue lead concentration, enhanced lead excretion, and reversed lead-induced alterations in superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) concentrations in mice, with CLIM205 showed better efficacy. The study indicates that LIM205 and CLIM205 have significant lead detoxification effect which will contribute to solve related problems. 相似文献
993.
994.
激光多普勒测速技术在气液两相流中的应用 总被引:1,自引:0,他引:1
本文采用激光颗粒动态分析仪(PDA)测量了钢包底部喷吹气液两相流中气泡的直径和气泡上升速度的分布;采用激光多普勒测速仪(LDA)测量了气液两相区和液体单相循环区液体速度场的分布。测量结果表明:气泡在脱离喷嘴上浮一定距离后,其大小基本保持不变;在气液两相区中,气泡速度和液体速度的分布均服从高斯分布;液体在单相区作循环流动,在侧壁与底部交接处,存在液体流动的“死区”。 相似文献
995.
The title complex, [Mn2(L)2(1,3-BDC)2]·0.25H2O 1 (L=2-(2-chloro-6-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline and 1,3-H2BDC=1,3-benzenedicarboxylic acid) has been obtained by using hydrothermal synthesis and characterized by elemental analysis, IR and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/n with a=1.751 68(6) nm, b=1.160 14(4) nm, c=2.585 30(8) nm, β=104.331(4)°, V=5.090 3(3) nm3, Z=4, C54H28.50Cl2F2Mn2N8O8.25, Mr=1 140.13, Dc=1.488 g·cm-3, F(000)=2 306, μ(Mo Kα)=0.673 mm-1, R=0.060 5 and wR=0.161 6. The compound 1 exhibits two-dimensional wavy layer structures, which are further stacked through π-π interactions to form three-dimensional supramolecular architectures. CCDC: 760201. 相似文献
996.
<正>The chemokine CXCR4 receptor is over-expressed in a wide variety of tumors.In this study,AMD3100,which was a prototype non-peptide antagonist of CXCR4 receptor,was labeled with ~(99m)Tc.~(99m)Tc-AMD3100 was verified by thin layer radio chromatography(TLRC).The tumor-localizing properties of ~(99m)Tc-AMD3100 were evaluated and proved in mice bearing Hep-G2 tumor xenograft.~(99m)Tc-AMD3100 was a promising,novel receptor-specific radiopharmaceutical with potential application in the imaging of human tumors. 相似文献
997.
Liang Chun Wu Long Qing Liu Hai Shan Jin Ming Liang Ma Xiao Li Zhao Ke Wen 《中国化学快报》2010,21(10):1263-1266
<正>Two pyrazine-contairting macrocyclic polyazomethines 2 and 3 were synthesized by direct[2 + 2]and[3 + 3]condensation reactions between 2,2'-[pyrazine-2,3-diylbis(oxy)]dibenzaldehyde(1) and hydrazine.Both 2 and 3 were characterized by NMR, HRMS,and their structures were determined via X-ray crystal diffraction studies. 相似文献
998.
A series of novel 7′-azaindirubin (1a-g) and 7-azaindirubin (2a, 2c, 2e and 2f) derivatives were designed and synthesized. Their structures were characterized by 1H NMR and MS spectroscopy as well as by elemental analysis. Their inhibitory properties against CDK2/cylinA were evaluated in vitro. In contrast to indirubin, some of the described azaindirubins emerged as potent inhibitors of CDK2/cylinA and compound 2b had more potent activity. Biological tests also showed that nitrogen atom at 7-position of azaindirubin was more beneficial to enhance the kinase inhibitory activity. 相似文献
999.
1000.
<正>Parkinson's disease(PD) is a common neurodegenerative disorder whose primary pathology features are the degeneration of dopaminergic neurons in the substantia nigra pars compacta(SNc) and the presence of eosinophilic inclusions called Lewy body in the cytoplasm of the remained neurons.Growing evidence suggests that dysfunction of the ubiquitin-proteasome system(UPS) is involved in the etiopathogenesis of PD.In order to investigate the pathogenetic mechanism of ubiquitin-proteasome dysfunction in PD,2D-differential gel electrophoresis (2D-DIGE) and MALDI-TOF Pro MS were used to determine the proteins,which were differentially expressed,in PC12 cells that had undergone a synthetic proteasomal inhibitor PSI(10μmol/L) treatment for 24 h.Forty-six protein spots were differentially expressed in response to PSI administration,of which 34 were increased and 12 decreased. Six of these were identified as molecular charperones:endoplasmin precursor(GRP94),heat shock protein 105(HSP105),HSC-70-psl,glucose ruglated protein 75(GRP75),glucose ruglated protein 58(GRP58) and heat shock 27000 protein 1(HSP27).The results suggest that the molecular chaperones play an important role in the PD model induced by proteasomal inhibitor. 相似文献