排序方式: 共有17条查询结果,搜索用时 187 毫秒
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在前文工作的基础上,结合MNDO/EHMO分子轨道方法和自然杂化轨道方法,具体计算了CC键和CP键的核自旋偶合常数.计算结果表明,1JCC和1JCP主要由成键原子的轨道杂化作用和键极性这两种结构因素所决定.为从简单价键理论角度解释和计算1JCC和1JCP值提供了简便直观的方法. 相似文献
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JA Drewry E Duodu A Mazouchi P Spagnuolo S Burger CC Gradinaru P Ayers AD Schimmer PT Gunning 《Inorganic chemistry》2012,51(15):8284-8291
Src Homology 2 (SH2) domains are the paradigm of phosphotyrosine (pY) protein recognition modules and mediate numerous cancer-promoting protein-protein complexes. Effective SH2 domain mimicry with pY-binding coordination complexes offers a promising route to new and selective disruptors of pY-mediated protein-protein interactions. We herein report the synthesis and in vitro characterization of a library of coordination complex SH2 domain proteomimetics. Compounds were designed to interact with phosphopeptides via a two-point interaction, principally with pY, and to make secondary interactions with pY+2/3, thereby achieving sequence-selective discrimination. Here, we report that lead mimetics demonstrated high target phosphopeptide affinity (K(a) ~ 10(7) M(-1)) and selectivity. In addition, biological screening in various tumor cells for anticancer effects showed a high degree of variability in cytotoxicity among receptors, which supported the proposed two-point binding mode. Several receptors potently disrupted cancer cell viability in breast cancer, prostate cancer, and acute myeloid leukemia cell lines. 相似文献
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Guillermo O. Menéndez Cecilia Samaniego López Elizabeth A. Jares‐Erijman Carla C. Spagnuolo 《Photochemistry and photobiology》2013,89(6):1354-1361
We have synthesized a near‐infrared emissive asymmetric tricarbocyanine conveniently functionalized to improve bioconjugation. The leading structure contains a versatile derivatization point at the meso position for facile radical‐nucleophilic aromatic substitution. We have evaluated a DPEN (N,N‐di(2‐picolyl)ethylendiamine) derivative of this dye as a highly selective sensor for zinc (II) in aqueous medium, which performs in an appropriate sensitivity range for biological studies. The probe was successfully conjugated to a protein‐ligand model with high affinity and specificity (biotin–streptavidin technology) rendering an excellent performance of sensing. In a general strategy to obtain sensitive probes combining fluorescent nanoparticles and molecular fluorophores, a preliminary design of a supramolecular assembly derived from the conjugation of the molecular sensor to quantum dots (QDs) was also investigated. The advantages and problems of FRET‐based sensors are also discussed. 相似文献
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Spagnuolo CC Vermeij RJ Jares-Erijman EA 《Journal of the American Chemical Society》2006,128(37):12040-12041
We have developed fluoro-substituted versions of the biarsenical-tetracysteine label FlAsH, exhibiting significant improvements in important properties over the original fluorescein derivative. In complexes with tetracysteine targets, F2FlAsH exhibits 50 times improved photostability, lower pH sensitivity, higher absorbance and quantum yield than FlAsH, and F4FlAsH adds a new color to the palette of biarsenical dyes. The two probes also provide a new FRET pair with a larger Ro value (54 A) than any previously obtained with biarsenical dyes. 相似文献
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γ-alkylation of α,β-unsaturated ketones: α'-phenylsulfonyl groups as regioselective control elements
Peter T. Lansbury Gregory E. Bebernitz Susan C. Maynard Ciro J. Spagnuolo 《Tetrahedron letters》1985,26(2):169-172
The α'-phenylsulfonyl derivative of E-3-penten-2-one () undergoes predominant γ-alkylation with a variety of alkyl iodides when first converted into a trilithiated intermediate with excess lithium diisopropylamide in tetrahydrofuran-hexane. 相似文献
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赵乃良 《高校应用数学学报(A辑)》1996,(1):91-96
Nira Dyn等提出的四点插值法是一种典型的自由曲线离散造型方法,但该方法不能控制插值点的切向。本文利用薄板样很可能 量的极小化原理给出了具有切向控制的四点分插值条件。用户可以方便地交互控制任一插值点的切向,使得四点插值法更为有效和实用。 相似文献
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Ostacolo L Russo P De Rosa G La Rotonda MI Maglio G Nese G Spagnuolo G Rengo S Oliva A Quaglia F 《Macromolecular bioscience》2008,8(7):682-689
The production of PEEA microspheres with potential as carriers for protein oral delivery is described. PEEAs with different hydrophilicity were synthesized and characterized. Experiments showed that an increase in copolymer hydrophilicity gave particles less prone to cell interaction. BSA release profiles from PEEA microspheres demonstrated that an increase in polymer hydrophilicity was useful in limiting protein burst and modulating drug delivery rate by increasing PEEA degradability. These results show that fine-tuning of the hydrophilic/hydrophobic properties of PCL is essential for the formulation protein-loaded microspheres with specific properties. 相似文献
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Alessia Antelmi Gennaro Cordasco Carmine Spagnuolo Przemysaw Szufel 《Entropy (Basel, Switzerland)》2021,23(7)
This work deals with a generalization of the minimum Target Set Selection (TSS) problem, a key algorithmic question in information diffusion research due to its potential commercial value. Firstly proposed by Kempe et al., the TSS problem is based on a linear threshold diffusion model defined on an input graph with node thresholds, quantifying the hardness to influence each node. The goal is to find the smaller set of items that can influence the whole network according to the diffusion model defined. This study generalizes the TSS problem on networks characterized by many-to-many relationships modeled via hypergraphs. Specifically, we introduce a linear threshold diffusion process on such structures, which evolves as follows. Let be a hypergraph. At the beginning of the process, the nodes in a given set are influenced. Then, at each iteration, (i) the influenced hyperedges set is augmented by all edges having a sufficiently large number of influenced nodes; (ii) consequently, the set of influenced nodes is enlarged by all the nodes having a sufficiently large number of already influenced hyperedges. The process ends when no new nodes can be influenced. Exploiting this diffusion model, we define the minimum Target Set Selection problem on hypergraphs (TSSH). Being the problem NP-hard (as it generalizes the TSS problem), we introduce four heuristics and provide an extensive evaluation on real-world networks. 相似文献