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Strong, low-energy two-photon absorption in extended amine-terminated cyano-substituted phenylenevinylene oligomers 总被引:8,自引:0,他引:8
Chung SJ Rumi M Alain V Barlow S Perry JW Marder SR 《Journal of the American Chemical Society》2005,127(31):10844-10845
Three quadrupolar oligophenylenevinylenes with five rings in the conjugated backbone, terminal donor groups, and various acceptors and/or donors along the backbone were synthesized and their two-photon spectroscopic properties investigated. These chromophores exhibit large two-photon absorption cross sections over a wide wavelength range and two distinct peaks, the strongest of which (deltamax > 3600 GM) is observed at 960-970 nm, a wavelength close to twice the value of the linear absorption maximum (2lambda(1)max). The findings on these chromophores are compared with those for analogous molecules with shorter conjugation length, for which the main two-photon band is at significantly shorter wavelength than 2lambda(1)max. 相似文献
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Maura Pellei Carlo Santini Giancarlo Gioia Lobbia Franco Cantalamessa Cinzia Nasuti Mariacristina Di Prinzio Rosita Gabbianelli Giancarlo Falcioni 《应用有机金属化学》2005,19(5):583-589
New organotin(IV) derivatives containing the anionic ligands bis(3,5‐dimethylpyrazol‐1‐yl)dithioacetate [LCS2]− and bis(3,5‐dimethylpyrazol‐1‐yl)acetate [LCO2]− have been synthesized from reaction between (CH3)2SnCl2 and lithium salts of the ligands. Mononuclear complexes of the type {[LCX2](CH3)2SnCl} (X = S or O) have been obtained and fully characterized by elemental analyses and FT‐IR in the solid state and by NMR (1H, 13C and 119Sn) spectroscopy, conductivity measurements and electrospray ionization mass spectrometry in solution. The acute toxicity of new organotin(IV) derivatives on rat was studied, comparing their effect with those of dimethyltin chloride (CH3)2SnCl2. The comparison of LD50 of organotin(IV) complexes and (CH3)2SnCl2 administered intraperitoneally, as a single dose, evaluated in vivo on rats, showed that toxicity decreases as follows: (CH3)2SnCl2 > LCO2 > LCS2. The effect of these organotin(IV) complexes on DNA was evaluated in vitro and in vivo on rats treated with different doses of these compounds (1/20 LD50 and 1/100 LD50). The lymphocyte DNA status was assessed by the comet assay, a rapid and sensitive single‐cell electrophoresis technique, used to detect primary DNA damage in individual cells. After 36 h from the start of treatment the two new organotin(IV) derivatives induced a significant rise in comet assay parameters, indicating an increasing presence of damaged DNA. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Mariacristina Cocca Maria Laura Di Lorenzo Mario Malinconico Vincenzo Frezza 《European Polymer Journal》2011,(5):1073-1080
The effect of crystal polymorphism on barrier and mechanical properties of PLLA is detailed in this contribution. PLLA films containing different amounts of α and α′ crystal forms were prepared by annealing quenched PLLA at different temperatures. The polymorphic structure of the films was analyzed by X-ray diffraction. Mechanical properties and permeability to water vapor were investigated as a function of degree of crystallinity (wC) and related to crystal polymorphism developed during annealing. The polymorphic structure of PLLA significantly affects mechanical and barrier properties. The α crystal modification provides a better barrier to water vapor and a higher Young’s modulus, compared to films containing the α′ modification, but a lower elongation at break. The varied barrier and mechanical properties were correlated to the different packing of PLLA chains in the two analyzed polymorphs. The conformational disorder of the α′ form makes this structure a mesophase (condis crystal), with remarkable effects on material properties. 相似文献
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Dr. Cristina Parisi Dr. Mariacristina Failla Dr. Aurore Fraix Dr. Barbara Rolando Dr. Eleonora Gianquinto Prof. Francesca Spyrakis Dr. Elena Gazzano Prof. Chiara Riganti Prof. Loretta Lazzarato Prof. Roberta Fruttero Prof. Alberto Gasco Prof. Salvatore Sortino 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(47):11080-11084
Two novel NO photodonors (NOPDs) based on BODIPY and Rhodamine antennae activatable with the highly biocompatible green light are reported. Both NOPDs exhibit considerable fluorescence emission and release NO with remarkable quantum efficiencies. The combination of the photoreleasing and emissive performance for both compounds is superior to those exhibited by other NOPDs based on similar light-harvesting centres, making them very intriguing for image-guided phototherapeutic applications. Preliminary biological data prove their easy visualization in cell environment due to the intense green and orange-red fluorescence and their photodynamic action on cancer cells due to the NO photo-liberated. 相似文献
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Following the increasing use of external and internal credit ratings made by the Bank regulation, credit risk concentration has become one of the leading topics in modern finance. In order to measure separately single-name and sectoral concentration risk, the literature proposes specific concentration indexes and models, which we review in this paper. Following the guideline proposed by Basel 2 on risk integration, we believe that standard approaches could be improved by studying a new measure of risk that integrates single-name and sectoral credit risk concentration in a coherent way. The main objective of this paper is to propose a novel index useful to measure credit risk concentration integrating single-name and sectoral components. From a theoretical point of view, our measure of risk shows interesting mathematical properties; empirical evidences are given on the basis of a data set. Finally, we have compared the results achieved following our proposal with respect to the common procedures proposed in the literature. 相似文献
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Mariacristina Uberti Simone Landini Simone Casellina 《Central European Journal of Operations Research》2014,22(2):391-406
Due to recent developments in credit markets, the interdependencies among fixed rate mortgages (FRMs) and adjustable rate mortgages (ARMs) markets are analysed in the study of the interactions within credit markets since it appears very suitable and interesting. A meaningful and complete database of information on Financial Institutions in Italy (1997:q1–2011:q4) hold by the Banca d’Italia shows that the relative importance of these markets recently displayed significant fluctuations since in 2005 fixed interest rate mortgage loans were about 10 % while in 2009 they raised up to 70 %. In the context of the FRMs and ARMs characteristics in Italian markets as well as the available database, among the proposed models for the study of interconnected markets (see Brock and Hommes in Econometrica 65(5):1059–1095, 1997, J Econ Dyn Control 22:1235–1274, 1998; Dieci and Westerhoff in Appl Math Comput 215:2011–2023, 2009; J Econ Behav Organ 75(3):461–481, 2010 and related literature cited therein), the models recently developed by Casellina et al. (Comput Econ 38:221–239, 2011) is applied to test its capacity to capture the dynamics of the observed data. It is worth stressing that the involved real data (volume of contracts and average interest rate in the FRMs and ARMs markets) are not sample information but they are evaluated on the entire population. The obtained findings point out the good level to fit the interest rates dynamics. Moreover, the model captures the switching mechanism and it catches the structural breaks when they occurs. 相似文献
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M. Sc. Qiang Wei M. Sc. Tobias Becherer Dr. Stefano Angioletti‐Uberti Prof. Dr. Joachim Dzubiella Dr. Christian Wischke Dr. Axel T. Neffe Prof. Dr. Andreas Lendlein Prof. Dr. Matthias Ballauff Prof. Rainer Haag 《Angewandte Chemie (International ed. in English)》2014,53(31):8004-8031
Protein adsorption is considered to be the most important factor of the interaction between polymeric biomaterials and body fluids or tissues. Water‐mediated hydrophobic and hydration forces as well as electrostatic interactions are believed to be the major factors of protein adsorption. A systematic analysis of various monolayer systems has resulted in general guidelines, the so‐called “Whitesides rules”. These concepts have been successfully applied for designing various protein‐resistant surfaces and are being studied to expand the understanding of protein–material interactions beyond existing limitations. Theories on the mechanisms of protein adsorption are constantly being improved due to the fast‐developing analytical technologies. This Review is aimed at improving these empirical guidelines with regard to present theoretical and analytical advances. Current analytical methods to test mechanistic hypotheses and theories of protein–surface interactions will be discussed. Special focus will be given to state‐of‐the‐art bioinert and biospecific coatings and their applications in biomedicine. 相似文献
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Monte Carlo computer simulations of systems of rigid anisometric molecules with axial ratio x 3, 4 and 5 have been performed at densities comparable to those of the mesogenic groups in liquid crystalline materials. The agreement between computer experiments and Flory-Ronca-Irvine theory is quite good. In particular, the nematic-isotropic transition temperatures found in the simulations are within 20 K of those predicted by the theory in all cases examined with x 3 and 4, and only slightly higher when x 5. Furthermore, the orientational distributions of the molecular long axes with respect to the nematic director are always nearly coincident with those evaluated according to the FRI theory, provided that the order parameter is the same. However, the order parameters at the transition points are smaller than expected on the basis of the theory, and closer to experimental values. Calculations performed by changing the size of the simulated systems prove that the reported results are size independent, while size dependent results are obtained with smaller systems. 相似文献
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Cristina Parisi Mariacristina Failla Aurore Fraix Luca Menilli Francesca Moret Elena Reddi Barbara Rolando Francesca Spyrakis Loretta Lazzarato Roberta Fruttero Alberto Gasco Salvatore Sortino 《Chemical science》2021,12(13):4740
The generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) as “unconventional” therapeutics with precise spatiotemporal control by using light stimuli may open entirely new horizons for innovative therapeutic modalities. Among ROS and RNS, peroxynitrite (ONOO−) plays a dominant role in chemistry and biology in view of its potent oxidizing power and cytotoxic action. We have designed and synthesized a molecular hybrid based on benzophenothiazine as a red light-harvesting antenna joined to an N-nitroso appendage through a flexible spacer. Single photon red light excitation of this molecular construct triggers the release of nitric oxide (˙NO) and simultaneously produces superoxide anions (O2˙−). The diffusion-controlled reaction between these two radical species generates ONOO−, as confirmed by the use of fluorescein-boronate as a highly selective chemical probe. Besides, the red fluorescence of the hybrid allows its tracking in different types of cancer cells where it is well-tolerated in the dark but induces remarkable cell mortality under irradiation with red light in a very low concentration range, with very low light doses (ca. 1 J cm−2). This ONOO− generator activatable by highly biocompatible and tissue penetrating single photon red light can open up intriguing prospects in biomedical research, where precise and spatiotemporally controlled concentrations of ONOO− are required.Excitation of a molecular hybrid with highly biocompatible red light generates cytotoxic peroxynitrite, produces red fluorescence useful for cell tracking and induces remarkable cancer cell death at very low concentrations and very low light doses. 相似文献