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71.
Laura Colomina – Alfaro;Paola Sist;Silvia Marchesan;Ranieri Urbani;Artemis Stamboulis;Antonella Bandiera; 《Macromolecular bioscience》2024,24(3):2300236
Elastin-like polypeptides are biotechnological protein and peptide carriers that offer a vast scope of applicability. This work aims to build a model for the expression of antimicrobial peptides (AMPs) by genetically engineering the Human Elastin-like Polypeptide platform developed in the lab. The well-characterized AMP indolicidin is selected as an example of an antimicrobial domain for the recombinant fusion at the C-terminus of the carrier. The fusion construct has been designed to allow the release of the antimicrobial domain. The expression product has been purified and its physicochemical and antimicrobial properties has been characterized. Taking advantage of the self-assembling and matrix-forming properties of the recombinant biopolymer, the materials that are obtained have been evaluated for antimicrobial activity toward bacterial-strain models. This approach represents a cost-effective strategy for the production of smart components and materials endowed with antimicrobial capacity triggered by external stimuli. 相似文献
72.
Pawandeep Singh Matharu;Abhishek Pratap Singh;Yuyang Song;Umesh Gandhi;Yonas Tadesse; 《Journal of polymer science. Part A, Polymer chemistry》2024,62(10):2071-2093
Soft silicone-based artificial skin is essential in soft robotics because of high elongation, safe human interaction, low energy requirements and ease of manufacturing. Inspired by nature, several attempts have been made to fabricate morphing structures using synthetic soft skin. In this study, a novel elastomeric skin is demonstrated featuring embedded actuators and micro-fluidic channels, that is capable of grasping objects. The actuators are twisted, and mandrel coiled nylon artificial muscles, with nichrome heaters that overcome key challenges in developing synthetic soft skin. The desired properties of a morphing skin are being low-cost, lightweight, highly deformable, compact size, silent cyclic actuation, fast response, and long life. The actuators are fabricated from 160 μm diameter resistance wires wrapped on twisted nylon 6 fishing line precursor fibers of 800 μm diameter. The wrapped nichrome (0.42 mm pitch) along with the twisted precursor fibers are coiled on a 1.4 mm diameter mandrel rod to obtain high strain. This muscle termed twisted, and mandrel coiled polymer fishing line muscle with nichrome is embedded in soft skin samples and tested. Characterization results on the actuators (3.2 mm in diameter) showed remarkable tensile actuation of ~36% strain from loaded length at 0.99 MPa for an input power of 4.9 W, a blocked stress of 1.27 MPa, an actuation frequency of 0.04 Hz, and a lifecycle >22,000 cycles. These actuators, when embedded in the soft skin of 4 mm thick, showed ~50% bending strain within 10s and a cyclic behavior with active water cooling. A soft gripper fabricated with embedded soft skin is integrated to our child-sized humanoid robot (HBS Robot) demonstrating its potential in grasping unconventional and deformable objects, hence advancing the progress in soft robotics. 相似文献
73.
复合材料承压结构是指采用复合材料制造的用于承受压力的部件,例如车载储氢容器、液氧贮箱、固体火箭发动机等.结构具有轻质高强、可设计性好等诸多优点,在航空航天、汽车和石化等领域得到广泛应用.然而在严苛服役条件下,复合材料承压结构的损伤积累及扩展极易导致部件失效,因此为提高其在役安全性,发展先进结构健康监测技术至关重要.本文首先详细对比了超声导波、声发射、红外、光纤光栅等监测方法的优缺点,重点阐述了复合材料承压结构健康监测方法及研究进展.其次,针对复合材料承压结构的材料特征,讨论了植入式微纳材料传感器在纤维/基体界面和层间性能监测方面应用及面临的关键挑战.最后,探讨了新型传感技术及人工智能方法的研发进展,并分析了其在复合材料承压结构在役安全保障领域的应用前景. 相似文献
74.
Zhuang Liu Yousef Faraj Xiao-Jie Ju Wei Wang Rui Xie Liang-Yin Chu 《Journal of polymer science. Part A, Polymer chemistry》2018,56(19):1306-1313
Responsive hydrogels have the ability to change their volume, transparency, or other properties in response to external chemical and/or physical stimuli. The responsiveness properties including responsive rate and degree, as well as mechanical properties such as Young's modulus, toughness, breaking strength, and breaking strain are crucial parameters of the smart hydrogels that determine the scope of hydrogel applications such as soft actuators, artificial muscles, and tissue engineering scaffolds. In this paper, the development of the nanocomposite smart hydrogels, which can achieve both improved responsiveness and mechanical properties, is reviewed. First, the fabrication approaches for building the nanocomposite networks by doping organic or inorganic nanomaterials via crosslinking or blending strategies are introduced. Then, the mechanisms used to improve both responsiveness and mechanical properties of nanocomposite responsive hydrogels are discussed. Finally, the perspectives as well as current challenges of such nanocomposite responsive hydrogels are addressed. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1306–1313 相似文献
75.
铁离子和硫氰化钾反应生成稳定的血红色络合物硫氰化铁,用智能手机拍摄所得图像的颜色反映在图像的RGB值上。随着该溶液浓度的增大,溶液颜色逐渐加深,反映在拍摄的图像中颜色的RGB值也在变化,并且得出该溶液颜色的R值与溶液的浓度成线性关系。结果显示,用该实验方法测得的抗贫血药物中铁的含量与用紫外分光光度法测得同一药品中铁的含量相比误差为5%;并且该实验方法在中学的化学实验课中很容易实现,避免了学生用目视比色法测量抗贫血药物中铁的含量时因标准溶液的色阶选择不合适而导致实验的失败。 相似文献
76.
77.
Jing Zhao Prof. Jingjun Liu Chun Jin Nan Wang Prof. Feng Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(55):12606-12614
The construction of nano-scale hybrid materials with a smart interfacial structure, established by using rare earth oxides and carbon as building blocks, is essential for the development of economical and efficient catalysts for oxygen reduction reactions (ORRs). In this work, hexagonal La2O3 nanocrystals on a nitrogen-doped porous carbon (NPC) derived from crop radish, served as building bricks, are prepared by chemical precipitation and then calcination at elevated temperatures. The obtained La2O3/NPC hybrid exhibits a very high ORR activity with a half-wave potential of 0.90 V, exceeding that of commercial Pt/C (0.83 V). Both DFT theoretical and experimental results have verified that the significantly enhanced catalytic performance is ascribed to the formation of the C−O−La covalent bonds between carbon and La2O3. Through the covalent bonds, electrons can transfer from the carbon to La2O3 and occupy the unfilled eg orbital of the La2O3 phase. This results in the accelerated adsorption of active oxygen and the facilitated desorption of the surface hydroxides (OHad−), thereby promoting the ORR over the catalyst. 相似文献
78.
远程医疗信息系统中,身份认证是确保患者和医疗服务器之间安全通信的有效机制。对Sutrala等基于口令的适用于远程医疗信息系统的用户匿名认证协议进行了安全性分析,指出其协议不能抵抗离线口令猜测攻击、中间人攻击,不具备前向安全性。基于扩展混沌映射提出了一个新的三因素匿名用户身份认证协议,新协议克服了Sutrala 等协议的安全漏洞。利用BAN(Burrows-Abadi-Needham)逻辑对提出方案进行了形式化证明。此外,安全分析表明,新的协议能够抵御各种恶意攻击,适用于远程医疗环境。 相似文献
79.
Ionizable amino acids in protein‐based hydrogels can confer pH‐responsive behavior. Because elastin‐like polypeptides (ELPs) have an established sequence and can crosslink to form hydrogels, they are an ideal system for creating pH‐sensitive materials. This study examines different parameters that might affect pH‐sensitive behavior and characterizes the mechanical and physical properties between pH 3 and 11 of three ELP‐based crosslinked hydrogels. The first finding is that varying the amount of crosslinker affects the overall stiffness and resilience of the hydrogels but does not strongly affect water content, swelling ratio, or pH sensitivity. Second, the choice of two popular tag sequences, which vary in histidine and aspartic acid content, does not have a strong effect on pH‐sensitive properties. Last, selectively blocking lysine and tyrosine residues through acetylation significantly decreases the pH‐sensitive zeta potential. Acetylated hydrogels also demonstrate different behavior at low pH values with reduced swelling, reduced water content, and higher stiffness. Overall, this work demonstrates that ELP hydrogels with ionizable groups are promising materials for environmentally‐responsive applications such as drug delivery, tissue engineering, and microfluidics. 相似文献
80.
Dan Savastru Laurentiu Baschir Sorin Miclos Roxana Savastru Ion Lancranjan 《Macromolecular Symposia》2020,389(1)
The purpose of this paper is to present a new method of detecting cracks that appear in the polymer matrix of a smart composite material using a self‐interference long period grating (SILPG) fiber sensor setup. Strain and torsion deformations of the polymer matrix induced by the cracks effects on SILPG are exploited for crack detection. Different other features of the crack mechanism that induce a change in the SILPG status and response are identified. The response of SILPG fiber sensor under host composite material host crack action is investigated and simulated for defining the functional limits of the composite material. SILPG fiber sensor is considered as embedded in polymer matrix of composite material. SILPG is operated as the signal source of the smart composite material feedback loop. 相似文献