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181.
182.
Self‐assembling amphiphilic block copolymer from renewable δ‐decalactone and δ‐dodecalactone
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Raffaele Ferrari Azzurra Agostini Lucia Brunel Lavinia Morosi Davide Moscatelli 《Journal of polymer science. Part A, Polymer chemistry》2017,55(22):3788-3797
Aliphatic polyesters have many applications in the biomedical field due to their properties and facile degradation. They are commonly synthesized via ring opening polymerization (ROP) with metal‐based catalysts, but as high temperatures are needed and the products contain metal, organocatalysts are now widely adopted to polymerize them at room temperature while also ensuring short reaction times. Here, 1,7,7‐triazabicyclo[4.4.0]‐dec‐5‐ene is used to polymerize less reactive but renewably‐derived lactones, namely δ‐decalactone and δ‐dodecalactone. These monomers were chosen in the attempt of creating renewable and highly lipophilic materials for drug delivery applications as alternatives to the more traditional, but non‐renewable δ‐valerolactone and ?‐caprolactone. A combination of ROP and living radical polymerization Reversible Addition‐Fragmentation Chain Transfer is proposed here to synthesize grafted block copolymers. They are able to self‐assemble in water, forming micelles where the lipophilic polyester core is able to entrap a lipophilic drug, thus making the system a good candidate for drug delivery. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3788–3797 相似文献
183.
Prof. Dr. Raffaele Saladino Dr. Veronica Neri Dr. Paola Checconi Dr. Ignacio Celestino Dr. Lucia Nencioni Prof. Dr. Anna Teresa Palamara Dr. Marcello Crucianelli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(7):2392-2404
This paper describes a new route for the synthesis of 1′‐homo‐N‐nucleoside derivatives by means of either methyltrioxorhenium (MTO) or supported MTO catalysts, with H2O2 as the primary oxidant. Under these selective conditions, the oxyfunctionalization of the heterocyclic ring and the N heteroatom oxidation were operative processes, regardless of the type of substrate used, that is, purine or pyrimidine derivatives. In addition, the oxidation of 1′‐homo‐N‐thionucleosides, showed the occurrence of site‐specific oxidative nucleophilic substitutions of the heterocyclic ring. The MTO/H2O2 system showed, in general, high reactivity under both homogeneous and heterogeneous conditions, affording the final products with high conversion values of substrates and from medium to high yields. Many of the novel 1′‐homo‐N‐nucleoside analogues were active against the influenza A virus, without any cytotoxic effects, retaining their activity in both protected and unprotected forms. 相似文献
184.
Isabelle Martiel Laurent Sagalowicz Raffaele Mezzenga 《Advances in colloid and interface science》2014
Phospholipids are ubiquitous cell membrane components and relatively well-accepted ingredients due to their natural origin. Phosphatidylcholine (PC) in particular offers a promising alternative to monoglycerides for lyotropic liquid crystalline (LLC) delivery system applications in the food, cosmetics and pharmaceutical industries, provided its strong tendency to form zero-mean curvature lamellar mesophases in water can be overcome. Higher negative curvatures are usually reached through the addition of a third lipid component, forming a ternary diagram phospholipid/water/oil. 相似文献
185.
We combine atomic force microscopy single-molecule analysis with polymer physics concepts to study molecular conformations of lysozyme amyloid fibrils. We resolve a wavy structure of the fibrils in which the scaling behavior varies at multiple length scales. Bond and pair correlation functions, end-to-end distribution, and wormlike chain model identify three characteristic length scales. At short length scales (≈150 nm), there is a first bending transition of the fibrils corresponding to a bending length L(b). At larger length scales (>2L(b)), fibrils become pseudoperiodic and start to undulate. Finally, at length scales larger than the persistence length (~ μm), the fibrils become flexible and follow a 2D self-avoiding random walk. We interpret these results in terms of the twisting of the fibrils and the impact this has on the area moment of inertia and the propensity of the fibril to bend. 相似文献
186.
Primo A Marino T Corma A Molinari R García H 《Journal of the American Chemical Society》2011,133(18):6930-6933
When irradiated with visible light (λ > 400 nm) 1 wt % gold-supported ceria nanoparticles generate oxygen from water (10.5 μmol·h(-1)) more efficiently than the standard WO(3) (1.7 μmol·h(-1)) even under UV irradiation (9.5 μmol·h(-1)). This remarkable photocatalytic activity arises from a novel preparation method to reduce the particle size of ceria (5 nm) by means of electrostatic binding of Ce(4+) to alginate gel, subsequent supercritical CO(2) drying, and calcination. The low loading of Au is crucial for the observed high catalytic activity. 相似文献
187.
A method which allows to approximate the Coulomb and exchange integrals employed in valence-electron-only SCF calculations with a few parameters, as described in a previous paper, is extended to the atoms from K to Zn. All the necessary parameters for these atoms are given. Extension to other atoms is in progress. 相似文献
188.
Antonio Laganà Ernesto Garcia Osvaldo Gervasi Ranieri Baraglia Domenico Laforenza Raffaele Perego 《Theoretical chemistry accounts》1991,79(3-4):323-333
Summary The calculation of rate constant values of theH+H
2 reaction for an extended range of excited vibrational states of the diatomic molecule and temperatures is relevant to the modeling ofH
– sources. To investigate the effect of isotopic substitutions on the efficiency of vibrational deexcitation processes, we extended the calculations to theD+D
2 system. These calculations were carried out using a program restructured to run on a shared memory vector and parallel computer. The dependence of the efficiency of vibrational deexcitation processes from both the initial vibrational state and temperature of reactants is reported. Restructuring strategies adopted for implementing the program on both shared and distributed memory computers as well as speedups achieved on both types of machines are also discussed. 相似文献
189.
Three sesquiterpenes: β-farnesene (I), γ-himachalene (II) and ar-curcumene (III) have been isolated from the title essential oil. The determination of the structure of γ-himachalene and his 13C-NMR. spectrum are described. 相似文献
190.
Raffaele Pisano 《BSHM Bulletin: Journal of the British Society for the History of Mathematics》2016,31(2):104-111
Leonardo da Vinci (1452–1519) maintained a strong relationship with mathematics, but the benefits of this connection unfortunately had little impact in his time. His meeting with Luca Pacioli (1445–1517) in Milan in 1496 was crucial: the two men would become friends and a deep mutual respect would preside over Leonardo da Vinci's improving his mathematical knowledge while contributing to the drawings of Pacioli's De divina proportione (Milano, 1496–98) (Pacioli 1509a). Based on my recent works on the relationship between mathematics and physics during the Renaissance, here I resume some results on the conceptual mathematical frameworks between two Italian scholars. 相似文献