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61.
Host–Guest Chemistry of a Bis‐Calix[4]pyrrole Derivative Containing a trans/cis‐Switchable Azobenzene Unit with Several Aliphatic Bis‐Carboxylates
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Grazia Cafeo Franz H. Kohnke Giovanni Mezzatesta Aldo Profumo Camillo Rosano Antonino Villari Andrew J. P. White 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5323-5327
The azobenzene unit used as a photochemically and thermally switchable linker in the assembly of a bis‐calix[4]pyrrole receptor provides a means to modulate the binding of bis‐carboxylates of significant biological importance in cancer research. Conversely, the complexation of different bis‐anionic guests has significant kinetic effects on both the photochemical and thermal trans/cis isomerization of the azobenzene unit. 相似文献
62.
Domenico Franco Giovanna Calabrese Salvatore Petralia Giulia Neri Carmelo Corsaro Lucia Forte Stefano Squarzoni Salvatore Guglielmino Francesco Traina Enza Fazio Sabrina Conoci 《Molecules (Basel, Switzerland)》2021,26(4)
Hydroxyapatite (HA) is the main inorganic mineral that constitutes bone matrix and represents the most used biomaterial for bone regeneration. Over the years, it has been demonstrated that HA exhibits good biocompatibility, osteoconductivity, and osteoinductivity both in vitro and in vivo, and can be prepared by synthetic and natural sources via easy fabrication strategies. However, its low antibacterial property and its fragile nature restricts its usage for bone graft applications. In this study we functionalized a MgHA scaffold with gold nanorods (AuNRs) and evaluated its antibacterial effect against S. aureus and E. coli in both suspension and adhesion and its cytotoxicity over time (1 to 24 days). Results show that the AuNRs nano-functionalization improves the antibacterial activity with 100% bacterial reduction after 24 h. The toxicity study, however, indicates a 4.38-fold cell number decrease at 24 days. Although further optimization on nano-functionalization process are needed for cytotoxicity, these data indicated that Au-NRs nano-functionalization is a very promising method for improving the antibacterial properties of HA. 相似文献
63.
Francesco Mallamace Carmelo Corsaro Enza Fazio Sow-Hsin Chen Domenico Mallamace 《中国科学:物理学 力学 天文学(英文版)》2019,(10)
We study the hydrogen bonds effect on the water density as a function of temperature and pressure from the supercritical region to the metastable supercooled and amorphous phases. We identify two important thermodynamic thresholds, that is P~*2■kbar and T~*■315 K, that separate two different water behaviors in terms of hydrogen bonding capability. For T T~* and P P~* the formation and stability of hydrogen bonded local structures are enhanced. The additional analyses of the proton NMR chemical shift and of the relaxation time confirm this evidence and highlight the structure breaking effects of the pressure. The investigation of both structural and dynamical quantities allow us to draw a complete picture of the water properties in terms of the temperaturepressure dependence of hydrogen bonding. 相似文献
64.
65.
Corsaro C Spooren J Branca C Leone N Broccio M Kim C Chen SH Stanley HE Mallamace F 《The journal of physical chemistry. B》2008,112(34):10449-10454
Proton nuclear magnetic resonance (1H NMR) experiments have been performed to measure the spin-lattice, T1, and spin-spin, T2, relaxation times of the three functional groups in water/methanol mixtures at different methanol molar fractions (XMeOH=0, 0.04, 0.1, 0.24, 0.5, 1) as a function of temperature in the range 205 K相似文献
66.
We present a study of the translational friction coefficients of spherical and ellipsoidal probes in nematic liquid crystalline fluids, based on the numerical treatment of Leslie-Ericksen equations [Q. J. Mech. Appl. Math. 19, 357 (1966); Adv. Liq. Cryst. 4, (1979); Trans. Soc. Rheol. 5, 23 (1961); Adv. Liq. Cryst. 2, 233 (1976)] for incompressible nematic fluids. Simulations of director dynamics in a local environment surrounding the moving probe are presented, and the dependence of translational diffusion on liquid crystal viscoelastic parameters is discussed. The time evolution of the director field is studied in the presence of an orienting magnetic field in two characteristic situations: Directors of motion parallel and perpendicular with respect to the field. In the particular case under investigation, a detailed analysis is given for the case of spherical, prolate, and oblate ellipsoidal probes in rectilinear motion in nematic (4-methoxibenzylidene-4'-n-butylaniline), together with a comparison with other nematogens, namely, 4,4'-dimethoxuazoxy benzene and (4'-n-pentyl-4-cyanobiphenil). A discussion of the general methodology presented in this work is given for the case of colloidal dispersions in nematic liquid crystals, which are considered as model systems of dispersions of particles in host media with anisotropic physical properties. 相似文献
67.
Antonino Drago 《Logica Universalis》2008,2(1):127-141
Each predicate of the Aristotelian square of opposition includes the word “is”. Through a twofold interpretation of this word
the square includes both classical logic and non-classical logic. All theses embodied by the square of opposition are preserved
by the new interpretation, except for contradictories, which are substituted by incommensurabilities. Indeed, the new interpretation
of the square of opposition concerns the relationships among entire theories, each represented by means of a characteristic
predicate. A generalization of the square of opposition is achieved by not adjoining, according to two Leibniz’ suggestions
about human mind, one more choice about the kind of infinity; i.e., a choice which was unknown by Greek’s culture, but which
played a decisive role for the birth and then the development of modern science. This essential innovation of modern scientific
culture explains why in modern times the Aristotelian square of opposition was disregarded.
This work was completed with the support of our -pert. 相似文献
68.
Libertino S Giannazzo F Aiello V Scandurra A Sinatra F Renis M Fichera M 《Langmuir : the ACS journal of surfaces and colloids》2008,24(5):1965-1972
A process to immobilize the enzyme glucose oxidase on SiO2 surfaces for the realization of integrated microbiosensors was developed. The sample characterization was performed by monitoring, step by step, oxide activation, silanization, linker molecule (glutaraldehyde) deposition, and enzyme immobilization by means of XPS, AFM, and contact angle measurements. The control of the environment during the procedure, to prevent silane polymerization, and the use of oxide activation to obtain a uniform enzyme layer are issues of crucial importance. The correct protocol application gives a uniform layer of the linker molecule and the maximum sample surface coverage. This result is fundamental for maximizing the enzyme bonding sites on the sample surface and achieving the maximum surface coverage. Thin SiO2 layers thermally grown on a Si substrate were used. The XPS Si 2p signal of the substrate was monitored during immobilization. Such a signal is not completely shielded by the thin oxide layer and it is fully suppressed after the completion of the whole protocol. A power spectral density analysis on the AFM measurements showed the crucial role of both the oxide activation and the intermediate steps (silanization and linker molecule deposition) to obtain uniform immobilized enzyme coverage. Finally, enzymatic activity measurements confirmed the suitability of the optimized protocol. 相似文献
69.
70.
Corsaro MM Pieretti G Lindner B Lanzetta R Parrilli E Tutino ML Parrilli M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(30):9368-9376
Many cold habitats contain plenty of microorganisms that represent the most abundant cold-adapted life forms on earth. These organisms have developed a wide range of adaptations that involve the cell wall of the microorganism. In particular, bacteria enhance the synthesis of unsaturated fatty acids of membrane lipids to maintain the membrane fluidity, but very little is known about the adaptational changes in the structure of the lipopolysaccharides (LPSs), the main constituent of the outer leaflet of the outer membrane of Gram-negative bacteria. The aim of this study was to investigate the chemical structure of these LPSs for insight into the temperature-adaptation mechanism. For this objective, the cold-adapted Psychromonas arctica bacterium, which lives in the arctic sea-water near Spitzbergen (Svalbard islands, Arctic) was cultivated at 4 degrees C. The lipooligosaccharides (LOSs) were isolated and analysed by means of chemical analysis and electrospray ionisation high-resolution Fourier transform mass spectrometry. The LOS was then degraded either by mild hydrazinolysis (O-deacylation) or with hot 4 M KOH (N-deacylation). Both products were investigated in detail by using 1H and 13C NMR spectroscopy and mass spectrometry. The core consists of a mixture of species that differ because of the presence of nonstoichiometric D-fructose and/or D-galacturonic acid units. 相似文献