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21.
Folliet N Roiland C Bégu S Aubert A Mineva T Goursot A Selvaraj K Duma L Tielens F Mauri F Laurent G Bonhomme C Gervais C Babonneau F Azaïs T 《Journal of the American Chemical Society》2011,133(42):16815-16827
In the context of nanomedicine, liposils (liposomes and silica) have a strong potential for drug storage and release schemes: such materials combine the intrinsic properties of liposome (encapsulation) and silica (increased rigidity, protective coating, pH degradability). In this work, an original approach combining solid state NMR, molecular dynamics, first principles geometry optimization, and NMR parameters calculation allows the building of a precise representation of the organic/inorganic interface in liposils. {(1)H-(29)Si}(1)H and {(1)H-(31)P}(1)H Double Cross-Polarization (CP) MAS NMR experiments were implemented in order to explore the proton chemical environments around the silica and the phospholipids, respectively. Using VASP (Vienna Ab Initio Simulation Package), DFT calculations including molecular dynamics, and geometry optimization lead to the determination of energetically favorable configurations of a DPPC (dipalmitoylphosphatidylcholine) headgroup adsorbed onto a hydroxylated silica surface that corresponds to a realistic model of an amorphous silica slab. These data combined with first principles NMR parameters calculations by GIPAW (Gauge Included Projected Augmented Wave) show that the phosphate moieties are not directly interacting with silanols. The stabilization of the interface is achieved through the presence of water molecules located in-between the head groups of the phospholipids and the silica surface forming an interfacial H-bonded water layer. A detailed study of the (31)P chemical shift anisotropy (CSA) parameters allows us to interpret the local dynamics of DPPC in liposils. Finally, the VASP/solid state NMR/GIPAW combined approach can be extended to a large variety of organic-inorganic hybrid interfaces. 相似文献
22.
Annick Laruelle 《European Journal of Operational Research》2021,288(2):598-604
In participatory budgeting, citizens are invited to vote on different projects. This paper sets out to study the voting stage of participatory budgeting from theoretical and practical perspectives. At theoretical level, the potential objectives of voting procedures are examined. From the practical point of view it should be easy to select projects, even when the number of projects is large. This paper proposes three algorithms which are theoretically justified and can be easily applied. Participatory budgeting in the town of Portugalete (Spain) provides a test for them. The results obtained with 2018 voting data suggest that the algorithm that includes the costs of the projects at the selection stage performs better than the others. KEYWORDS: decision processes; participatory budgeting; collective decision-making; cost-benefit analysis. 相似文献
23.
Aurélie Rolle Helen Seymour Pascal Roussel Annick Rubbens Rose-Noëlle Vannier 《Ionics》2008,14(6):477-482
The Ba2In2 − x
Sn
x
O5 + x/2 solid solution was confirmed up to x = 1 by solid-state reaction. X-ray diffraction at room and at elevated temperatures, Raman scattering and impedance spectroscopy
were used to characterise the samples. The structure refinement of the composition x = 0.1 from neutron diffraction data reveals that tin is preferentially located in the tetrahedral layers of the brownmillerite.
Paper presented at the 11th EuroConference on the Science and Technology of Ionics, Batz-sur-Mer, Sept. 9–15, 2007 相似文献
24.
25.
Dubs P Bourel-Bonnet L Subra G Blanpain A Melnyk O Pinel AM Gras-Masse H Martinez J 《Journal of combinatorial chemistry》2007,9(6):973-981
alpha-Melanocyte-stimulating hormone (alpha-MSH) is an endogeneous linear tridecapeptide with potential application for the modulation of skin tanning. To evaluate the interest of introducing a lipid moiety onto this peptide, we developed an efficient chemoselective parallel method to prepare a large series of analogues of alpha-melanocortin with high purity, varying the nature or the relative position of the lipid moiety. Two sets of building blocks containing lipidic alpha-oxo-aldehydes or alpha-hydrazinoacetyl peptides were combined to obtain a 102-membered library of amphiphilic alpha-MSH analogues. This library was pharmacologically tested at 1 x 10(-7) M for the ability to induce AMPc production in M4Be melanoma cell line after stimulation of the human melanocortin MC1 receptor. Among theses lipopeptides, 84 compounds exhibited an AMPc induction higher than Melitane, a patented alpha-MSH agonist. These results provide strong evidence of the interest of introduction of a lipid tail for the pharmacomodulation of bioactive peptides. 相似文献
26.
27.
Robin Cellier Sylvain Brail Julien Barre Ekaterina Epova Anne-Laure Ronzani Cornelis Van Leeuwen Stanislas Milcent Patrick Ors Olivier F. X. Donard 《Molecules (Basel, Switzerland)》2021,26(16)
The 87Sr/86Sr ratio of 39 Champagnes from six different brands, originating from the whole “Appellation d’Origine Contrôlée” (AOC) Champagne was analyzed to establish a possible relation with the geographical origin. Musts (i.e., grape juice) and base wines were also analyzed to study the evolution of the Sr isotopic ratio during the elaboration process of sparkling wine. The results demonstrate that there is a very homogeneous Sr isotopic ratio (87Sr/86Sr = 0.70812, n = 37) and a narrow span of variability (2σ = 0.00007, n = 37). Moreover, the Sr concentrations in Champagnes have also low variability, which can be in part explained by the homogeneity of the bedrock in the AOC Champagne. Measurements of the 87Sr/86Sr ratio from musts and base wines show that blending during Champagne production plays a major role in the limited variability observed. Further, the 87Sr/86Sr of the musts were closely linked to the 87Sr/86Sr ratio of the vineyard soil. It appears that the 87Sr/86Sr of the product does not change during the elaboration process, but its variability decreases throughout the process due to blending. Both the homogeneity of the soil composition in the Champagne AOC and the blending process during the wine making process with several blending steps at different stages account for the unique and stable Sr isotopic signature of the Champagne wines. 相似文献
28.
S. Barre J. Rolland G. Boitel E. Goncalves R. Fortes Patella 《European Journal of Mechanics - B/Fluids》2009,28(3):444-464
Correlated experimental and numerical studies were carried out to analyze cavitating flows and to describe the two-phase flow structures of attached sheet cavitation in Venturi geometries. New double optical probe measurements were performed and special data processing methods were developed to estimate void ratio and velocity fields for cold water flows.By applying a computational method previously developed in LEGI (Laboratoire des Ecoulements Géophysiques et Industriels, Grenoble, France) based on the code FineTM/Turbo and on a barotropic approach, several steady calculations were performed in cold water cavitating flows. Local and global analyzes based on comparisons between experimental and numerical results were proposed. 相似文献
29.
We consider the Hermite trigonometric interpolation problem of order 1 for equidistant nodes, i.e., the problem of finding a trigonometric polynomial t that interpolates the values of a function and of its derivative at equidistant points. We give a formula for the Fourier coefficients of t in terms of those of the two classical trigonometric polynomials interpolating the values and those of the derivative separately. This formula yields the coefficients with a single FFT. It also gives an aliasing formula for the error in the coefficients which, on its turn, yields error bounds and convergence results for differentiable as well as analytic functions. We then consider the Lagrangian formula and eliminate the unstable factor by switching to the barycentric formula. We also give simplified formulae for even and odd functions, as well as consequent formulae for Hermite interpolation between Chebyshev points. 相似文献
30.
Base-catalysed addition of methanol to propargylic sulfones selectively gave β-ketosulfones whereas mercuric salts catalysed additions gave γ-ketosulfones. The latter process has been used to prepare one half of pyrenophorine. 相似文献