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排序方式: 共有1124条查询结果,搜索用时 375 毫秒
921.
Francesco Sannicol Serena Arnaboldi Tiziana Benincori Valentina Bonometti Roberto Cirilli Lothar Dunsch Wodzimierz Kutner Giovanna Longhi Patrizia R. Mussini Monica Panigati Marco Pierini Simona Rizzo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(10):2661-2665
The typical design of chiral electroactive materials involves attaching chiral pendants to an electroactive polyconjugated backbone and generally results in modest chirality manifestations. Discussed herein are electroactive chiral poly‐heterocycles, where chirality is not external to the electroactive backbone but inherent to it, and results from a torsion generated by the periodic presence of atropisomeric, conjugatively active biheteroaromatic scaffolds, (3,3′‐bithianaphthene). As the stereogenic element coincides with the electroactive one, films of impressive chiroptical activity and outstanding enantiodiscrimination properties are obtained. Moreover, chirality manifestations can be finely and reversibly tuned by the electric potential, as progressive injection of holes forces the two thianaphthene rings to co‐planarize to favor delocalization. Such deformations, revealed by CD spectroelectrochemistry, are elastic and reversible, thus suggesting a breathing system. 相似文献
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Maria Cristina Paganini Valentina Brunella Mario Chiesa 《Magnetic resonance in chemistry : MRC》2012,50(9):615-619
Ultra high molecular weight polyethylene (UHMWPE) has been studied with different magnetic resonance techniques to elicit information on the nature and the location of radicals generated during high energy irradiation. Field swept electron paramagnetic resonance, pulsed Davies electron nuclear double resonance and hyperfine sublevel correlation spectroscopic measurements allowed extracting for the first time the full 1H hyperfine coupling tensors of the most abundant radical, i.e. a secondary alkyl radical and to ascertain the formation of allyl radicals in the first stages of the irradiation process. The 1H hyperfine coupling tensors are analogous to those reported for single crystal irradiated polyethylene, suggesting that radicals generated in UHMWPE are located in the crystalline region of the polymer. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Massimiliano Papi Valentina Palmieri Giuseppe Maulucci Giuseppe Arcovito Emanuela Greco Gianluca Quintiliani Maurizio Fraziano Marco De Spirito 《Journal of nanoparticle research》2011,13(11):6141-6147
In recent years carrier-mediated drug delivery has emerged as a powerful methodology for the treatment of various pathologies.
The therapeutic index of traditional and novel drugs is enhanced via the increase of specificity due to targeting of drugs
to a particular tissue, cell or intracellular compartment, the control over release kinetics, the protection of the active
agent, or a combination of the above. Collagen is an important biomaterial in medical applications and ideal as protein-based
drug delivery platform due to its special characteristics, such as biocompatibility, low toxicity, biodegradability, and weak
antigenicity. While some many attempts have been made, further work is needed to produce fully biocompatible collagen hydrogels
of desired size and able to release drugs on a specific target. In this article we propose a novel method to obtain spherical
particles made of polymerized collagen surrounded by DMPC liposomes. The liposomes allow to control both the particles dimension
and the gelling environment during the collagen polymerization. Furthermore, an optical based method to visualize and quantify
each step of the proposed protocol is detailed and discussed. 相似文献
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Mariangela Marrelli Francesca Pisani Valentina Amodeo Pierre Duez 《Natural product research》2020,34(18):2664-2667
AbstractThe methanolic extract of Echinophora tenuifolia L. branches and its fractions were evaluated for their in vitro cell growth inhibitory activity on different human cancer cell lines (C32, LoVo and SKBr3) and the normal BJ fibroblasts. All tested samples were effective against the melanoma cell line C32, with IC50 values ranging from 22.8?±?0.8 to 78.7?±?1.2?μg/mL, the antiproliferative activity of the dichloromethane fraction being significantly higher. This fraction was also effective against the LoVo adenocarcinoma cell line, with an IC50 value of 53.0?±?2.1?μg/mL. The ethyl acetate and dichloromethane fractions showed the highest lipid peroxidation inhibitory activity, verified by means of the β-carotene bleaching test. The phytochemical profiles of E. tenuifolia branches extract were established by means of GC-MS and HPTLC. Overall, branches of E. tenuifolia L. could represent a rich source of bioactive compounds, potentially useful in the pharmaceutical field. 相似文献