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1.
A simple and efficient approach is reported to estimate the sparsest Tucker3 model for a considered linear dependent multiway data array using PARAFAC profiles. Employing the least possible number of non‐zero core elements equal to the pseudo array rank of data, a better and easier interpretation of the data array is possible. The approach does not require any prior information. The type of rank deficiency, that is rank overlap or closure in different modes, and the Tucker3 core size can be determined from a congruency factor while running the algorithm. The replacement method (RM) of optimization is applied to determine the pattern (positions and values) of non‐zero elements in the sparsest core of the Tucker3 model. Full rank and rank deficient simulated data sets in different conditions as well as an experimental 3D fluorescence data set from gold nanoparticle (AuNP) interaction with HIV genome are successfully used for evaluating the performance of the algorithm. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

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Gold–carbene complexes are essential intermediates in many gold‐catalyzed organic‐synthetic transformations. While gold–carbene complexes with direct, vinylogous, or phenylogous heteroatom substitution have been synthesized and characterized, the observation in the condensed phase of electronically non‐stabilized gold–carbenes has so far remained elusive. The sterically extremely shielded, emerald‐green complex [IPr**Au=CMes2]+[NTf2]? has now been synthesized, isolated, and fully characterized. Its absorption maximum at 642 nm, in contrast to 528 nm of the red‐purple carbocation [Mes2CH]+, clearly demonstrates that gold is more than just a “soft proton”.  相似文献   

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A new generation of saturated benzene mimetics, 2‐oxabicyclo[2.1.1]hexanes, was developed. These compounds were designed as analogues of bicyclo[1.1.1]pentane with an improved water solubility. Crystallographic analysis of 2‐oxabicyclo[2.1.1]hexanes revealed that they occupy a novel chemical space, but, at the same time, resemble the motif of meta‐disubstituted benzenes.  相似文献   

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Non‐Newtonian fluids are ubiquitous in daily life and industrial applications. Herein, we report an intelligent fluidic system integrating two distinct non‐Newtonian rheological properties mediated by an autocatalytic enzyme reaction. Associative polyelectrolytes bearing a small amount of ionic and alkyl groups are engineered: by carefully balancing the charge density and the hydrophobic effect, the polymer solutions demonstrate a unique shear thickening property at low pH while shear thinning at high pH. The urea‐urease clock reaction is utilized to program a feedback‐induced pH change, leading to a strong upturn of the nonlinear viscoelastic properties. As long as the chemical fuel is supplied, two distinct non‐Newtonian states can be achieved with a tunable lifetime span. As a proof of concept, we demonstrate how the physical energy‐driven nonequilibrium properties can be manipulated by a chemical‐fueled process.  相似文献   

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An analytical theory describing layers of polymer chains grafted to a planar surface (i.e. polymer brush) is developed. We consider a brush of chains with finite extensibility (or non‐Gaussian brush) within the framework of molecular field theory. An analytical solution for free energy of the brush and a few other brush characteristics are obtained and studied. Comparison with other known models of a brush is also made.

Chain extensibility E(x, y) for Gaussian model (dashed lines) and BCC model (solid lines) for a few chain end positions y (numbers near curves).  相似文献   


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Growth of covalent organic frameworks (COFs) as single crystals is extremely challenging. Inaccessibility of open‐structured single‐crystal COFs prevents the exploration of structure‐oriented applications. Herein we report for the first time a non‐interpenetrated single‐crystal COF, LZU‐306, which possesses the open structure constructed exclusively via covalent assembly. With a high void volume of 80 %, LZU‐306 was applied to investigate the intrinsic dynamics of reticulated tetraphenylethylene (TPE) as the individual aggregation‐induced‐emission moiety. Solid‐state 2H NMR investigation has determined that the rotation of benzene rings in TPE, being the freest among the reported cases, is as fast as 1.0×104 Hz at 203 K to 1.5×107 Hz at 293 K. This research not only explores a new paradigm for single‐crystal growth of open frameworks, but also provides a unique matrix‐isolation platform to reticulate functional moieties into a well‐defined and isolated state.  相似文献   

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如何筛选合理的数据库匹配结果对于基于质谱的蛋白质组学研究至关重要。但是目前,基于打分体系和反转数据库的筛选方法都无法有效的避免假阳性和假阴性匹配的存在。因此,本文提出了一种系统的搜索策略: 非同质荷比检索规则 (INMZS)。在该策略中,所有匹配结果都需要检查相关匹配质荷比的分享程度,只有那些相关质荷比均为专有匹配时,蛋白质才会被作为可信结果保留,策略还采用迭代搜索方法以提高鉴定低丰度组分的灵敏度。最终,所有的匹配结果由诱饵数据库方法进行评估以得到最终结果列表。INMZS策略在标准蛋白质混合物和大规模人肝蛋白质组数据上进行了模拟及应用,结果显示,INMZS规则和诱饵数据库评估方法的结和可以有效的保证蛋白质组学数据匹配的可信度及灵敏度,可以广泛适用于基于二维凝胶电泳及非shotgun技术的蛋白组学研究中。  相似文献   

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The advantages of zinc catalysts, such as their low toxicity, low cost, and environmentally benignity, are encouraging organic chemists to explore their applications in organic synthesis. As a non‐redox metal, zinc catalysts have been investigated in redox reactions over the past few decades. Because of the importance of redox reactions, the interest in zinc catalysts, and the fact that no review on zinc‐catalyzed redox reactions has been published, herein, I have collected and summarized the main contributions in this area. This review is divided into two parts: reduction reactions and oxidation reactions.  相似文献   

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Molecular hydrides of the rare‐earth metals play an important role as homogeneous catalysts and as counterparts of solid‐state interstitial hydrides. Structurally well‐characterized non‐metallocene‐type hydride complexes allow the study of elementary reactions that occur at rare‐earth‐metal centers and of catalytic reactions involving bonds between rare‐earth metals and hydrides. In addition to neutral hydrides, cationic derivatives have now become available.  相似文献   

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Site‐selective growth on non‐spherical seeds provides an indispensable route to hierarchical complex nanostructures that are interesting for diverse applications. However, this has only been achieved through epitaxial growth, which is restricted to crystalline materials with similar crystal structures and physicochemical properties. A non‐epitaxial growth strategy is reported for hierarchical nanostructures, where site‐selective growth is controlled by the curvature of non‐spherical seeds. This strategy is effective for site‐selective growth of silica nanorods from non‐spherical seeds of different shapes and materials, such as α‐Fe2O3, NaYF4, and ZnO. This growth strategy is not limited by the stringent requirements of epitaxy and is thus a versatile general method suitable for the preparation of hierarchical nanostructures with controlled morphologies and compositions to open up a verity of applications in self‐assembly, nanorobotics, catalysis, electronics, and biotechnology.  相似文献   

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Under certain conditions, repetitive DNA motifs have the potential to adopt non‐B‐form DNA structures, such as hairpins, triplexes, Z‐DNA, quadruplexes, and i‐motifs. Some non‐B‐form DNAs have been proposed to cause mutations and, consequently, participate in several biologically important processes, including regulation, evolution, and human disease. Advancement in the knowledge of specific interactions between molecules and non‐B‐form DNAs at the molecular level in living cells is important for understanding their biological functions. In this review, we describe the latest studies on molecules that target non‐B‐form DNAs in vivo, with a focus on Z‐DNA, G‐quadruplexes, triplexes, i‐motifs, and hairpins.  相似文献   

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Multistimuli‐responsive shape‐memory polymers are highly desirable in various applications, and numerous modes have been developed in recent years. However, most of them need to reprogram before they are ready to respond to another stimulus while one is triggered. Here, a new strategy is developed to achieve dual‐stimuli‐responsive triple‐shape memory with non‐overlapping effect in one programming cycle. Here, a series of poly(l ‐lactide)‐poly(tetramethylene oxide) glycol copolymers (PLA‐PTMEG‐A) is prepared by selected dangling photoresponsive anthracene moieties on the crystalline PTMEG backbone. The architectures of the copolymers are well‐controlled in order to keep a good balance between the crystallinity of the soft segment and the mobility of the anthracene moieties. Thus, PLA‐PTMEG‐A's can respond to heat and light with non‐overlapping effect. The thermally‐induced shape‐memory effect (TSME) is realized by the crystallization–melting transition of PTMEG soft segments, while the light‐induced shape‐memory effect (LSME) is achieved by the reversible photodimerization of anthracene groups. In view of the non‐overlapping effect of TSME and LSME in the copolymers, a triple‐shape‐memory effect triggered by dual‐stimuli is realized in one programming and recovery cycle.

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