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排序方式: 共有373条查询结果,搜索用时 15 毫秒
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Mariana Tasso Ana L. Cordeiro Katrin Salchert Carsten Werner 《Macromolecular bioscience》2009,9(9):922-929
Enzymes cleaving the biopolymer adhesives of fouling organisms are attracting attention for the prevention of biofouling. We report a versatile and robust method to confine the serine protease Subtilisin A (or Subtilisin Carlsberg) to surfaces to be protected against biofouling. The approach consists of the covalent immobilization of the protease onto maleic anhydride copolymer thin film coatings. High‐swelling poly(ethylene‐alt‐maleic anhydride) (PEMA) copolymer layers permitted significantly higher enzyme loadings and activities than compact poly(octadecene‐alt‐maleic anhydride) (POMA) films. Substantial fractions of the immobilized, active enzyme layers were found to be conserved upon storage in deionized water for several hours. Ongoing studies explore the potentialities of the developed bioactive coatings to reduce the adhesion of various fouling organisms.
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研究了两种马来酸酐接枝聚丙烯(PP-g-MAH)在不同含量时对聚丙烯(PP)/滑石粉复合材料的力学性能、雾化性能和线性膨胀系数的影响.结果表明,接枝物的加入能提高复合材料的拉伸性能、冲击性能和弯曲性能,但随着含量的增加拉伸强度、冲击强度和弯曲强度及弯曲模量有所降低.在含量相同时,接枝物1对冷凝组份的影响更小.复合材料的线性膨胀系数随接枝物含量的增加先减小后增加. 相似文献
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Yun Hin Taufiq-Yap 《天然气化学杂志》2006,15(2):144-148
In this study, Cr and Co promoted, as well as unpromoted vanadium phosphate (VPO) catalysts were synthesized by the reaction of V2O5 and o-H3PO4 in organic medium followed by calcination in n-butane/air environment at 673 K. The physico-chemical properties and the catalytic behavior were affected by the addition of Cr and Co dopants. H2-TPR was used to investigate the nature of oxidants in the unpromoted and promoted catalysts. The results showed that both the Cr and Co promoters remarkably lowered the temperature of the reduction peak associated with V5 . The amount of oxygen species originated from the active phase, V4 , removed was significantly increased for Co and Cr-promoted catalysts. Both Cr and Co dopants improve strongly the n-butane conversion without sacrificing the MA selectivity. A good correlation was observed between the amount of oxygen species removed from V4 phase and the activity for n-butane oxidation to maleic anhydride. This suggested that V4 -O was the center for the activation of n-butane. 相似文献
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用于丁烷选择氧化制顺酐的铈锆复合钒磷氧催化剂的研究 总被引:2,自引:2,他引:2
在钒磷氧(VPO)催化剂中添加适量铈锆复合氧化物,得到了一\r\n种新型的铈锆复合钒磷氧催化剂.该催化剂对丁烷选择性氧化制顺酐反\r\n应的催化性能比纯VPO催化剂有了显著提高.在丁烷/空气共进料反应\r\n条件下,其顺酐收率比纯VPO催化剂提高了一倍;在无氧反应条件下,\r\n其可参与选择性氧化制顺酐的晶格氧量为纯VPO催化剂的2.2倍.BET比\r\n表面积测试、X射线衍射、钒平均价态测定和程序升温实验等表征结果\r\n表明,混合在催化剂活性相中的少量铈锆复合氧化物参与了VPO体系的\r\n氧化还原过程,并起到了以下两方面的作用:(1)促进了(VO)2P2O\r\n7相的形成,稳定了钒的平均价态,有利于最终形成晶相结构良好和反\r\n应性能稳定的VPO催化剂;(2)显著提高了VPO催化剂的氧化还原性能\r\n,大大增加了催化剂的可逆储氧量. 相似文献
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Anqi Tao George Lo Huang Kazunori Igarashi Taehun Hong Suiyang Liao Francesco Stellacci Yu Matsumoto Tatsuya Yamasoba Kazunori Kataoka Horacio Cabral 《Macromolecular bioscience》2020,20(1)
Protein drugs have great potential as targeted therapies, yet their application suffers from several drawbacks, such as instability, short half‐life, and adverse immune responses. Thus, protein delivery approaches based on stimuli‐responsive nanocarriers can provide effective strategies for selectively enhancing the availability and activation of proteins in targeted tissues. Herein, polymeric micelles with the ability of encapsulating proteins are developed via concurrent ion complexation and pH‐cleavable covalent bonding between proteins and block copolymers directed to pH‐triggered release of the protein payload. Carboxydimethylmaleic anhydride (CDM) is selected as the pH‐sensitive moiety, since the CDM? amide bond is stable at physiological pH (pH 7.4), while it cleaves at pH 6.5, that is, the pathophysiological pH of tumors and inflammatory tissues. By using poly(ethylene glycol)‐poly(l ‐lysine) block copolymers having 45% CDM addition, different proteins with various sizes and isoelectric points are loaded successfully. By using myoglobin‐loaded micelles (myo/m) as a model, the stability of the micelles in physiological conditions and the dissociation and release of functional myoglobin at pH 6.5 are successfully confirmed. Moreover, myo/m shows extended half‐life in blood compared to free myoglobin and micelles assembled solely by polyion complex, indicating the potential of this system for in vivo delivery of proteins. 相似文献