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排序方式: 共有100条查询结果,搜索用时 31 毫秒
1.
Alberta Terzi Nunzia Gallo Simona Bettini Teresa Sibillano Davide Altamura Marta Madaghiele Liberato De Caro Ludovico Valli Luca Salvatore Alessandro Sannino Cinzia Giannini 《Macromolecular bioscience》2020,20(5)
Collagen represents one of the most widely used biomaterial for scaffolds fabrication in tissue engineering as it represents the mechanical support of natural tissues. It also provides physical scaffolding for cells and it influences their attachment, growth, and tissue regeneration. Among all fibrillary collagens, type I is considered one of the gold standard for scaffolds fabrication, thanks to its high biocompatibility, biodegradability, and hemostatic properties. It can be extracted by chemical and enzymatic protocols from several collagen‐rich tissues, such as tendon and skin, of different animal species. Both the extraction processes and the manufacturing protocols for scaffolds fabrication provide structural and mechanical changes that can be tuned in order to deeply impact the properties of the final biomaterial. The aim of this review is to discuss the role of X‐rays to study structural changes of type I collagen from fresh collagen‐rich tissues (bovine, equine, fish) to the final scaffolds, with the aim to screen across available collagen sources and scaffolds fabrication protocols to be used in tissue regeneration. 相似文献
2.
B. J. Geurts A. Tomboulides D. von Terzi W. Rodi 《Flow, Turbulence and Combustion》2013,91(3):429-430
3.
Brian B. Frank Berta Camafort Blanco Samuel Jakob Fiammetta Ferroni Silvia Pieraccini Dr. Alberta Ferrarini Prof. Dr. Corinne Boudon Prof. Dr. Jean‐Paul Gisselbrecht Dr. Paul Seiler Gian Piero Spada Prof. Dr. François Diederich Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(36):9005-9016
Axially chiral, N‐arylated 3,5‐dihydro‐4H‐dinaphtho[2,1‐c:1′,2′‐e]azepines have been prepared by short synthetic protocols from enantiopure 1,1′‐bi(2,2′‐naphthol) (BINOL) and anilines. Alkynes substituted with two N‐phenyldinaphthazepine donors readily undergo a formal [2+2] cycloaddition, followed by retro‐electrocyclization, with tetracyanoethene (TCNE) to yield donor‐substituted 1,1,4,4‐tetracyanobuta‐1,3‐dienes (TCBDs) featuring intense intramolecular charge‐transfer (CT) interactions. A dicyanovinyl derivative substituted with one N‐phenyldinaphthazepine donor was obtained by a “one‐pot” oxidation/Knoevenagel condensation from the corresponding propargylic alcohol. Comparative electrochemical, X‐ray crystallographic, and UV/Vis studies show that the electron‐donor qualities of N‐phenyldinaphthazepine are similar to those of N,N‐dimethylanilino residues. The circular dichroism (CD) spectrum of a push–pull chromophore incorporating the chiral donor moiety features Cotton effects of exceptional intensity. With their elongated shape and the rigidity of the chiral N‐aryldinaphthazepine donors, these chromophores are effective inducers of twist distortion in nematic liquid crystals (LCs). Thus, a series of the dinaphthazepine derivatives was used as dopants in the nematic LC E7 (Merck) and high helical twisting powers (β) of the order of hundreds of μm?1 were measured. Theoretical calculations were employed to elucidate the relation between the structure of the dopants and their helical twisting power. For the derivatives with two dinaphthazepine moieties, a strong dependence of the β‐values on the structure and conformation of the linker between them was found. 相似文献
4.
Martina Mazzoni Lorenzo Franco Alberta Ferrarini Carlo Corvaja Giovanni Zordan Gianfranco Scorrano 《Liquid crystals》2013,40(2):203-208
A nitroxide [60]fullerene adduct containing a pyrrolidine-1-oxyl group has been synthesized. Its orientational order in the nematic phase of the liquid crystal solvent 4,4′-azoxyanisole (PAA) has been measured from the variation of the EPR spectral parameters on passing from the isotropic to the nematic phase. Highly resolved EPR lines allow for precise evaluation of the shifts of the g, a N and a H values. Since the g and the hyperfine tensors are known, the order matrix could be obtained. This is compared with the one calculated with a theoretical model based on short range solute-solvent interactions, which predicts a considerable degree of orientation of the molecular axes, despite the almost spherical shape of the molecule. The agreement with experimental findings is quite good and it is further improved if a bent structure of the pyrrolidine ring is taken into account. 相似文献
5.
Martina Mazzoni Lorenzo Franco Alberta Ferrarini Carlo Corvaja Giovanni Zordan Gianfranco Scorrano Michele Maggini 《Liquid crystals》2002,29(2):203-208
A nitroxide [60]fullerene adduct containing a pyrrolidine-1-oxyl group has been synthesized. Its orientational order in the nematic phase of the liquid crystal solvent 4,4'-azoxyanisole (PAA) has been measured from the variation of the EPR spectral parameters on passing from the isotropic to the nematic phase. Highly resolved EPR lines allow for precise evaluation of the shifts of the g , a N and a H values. Since the g and the hyperfine tensors are known, the order matrix could be obtained. This is compared with the one calculated with a theoretical model based on short range solute-solvent interactions, which predicts a considerable degree of orientation of the molecular axes, despite the almost spherical shape of the molecule. The agreement with experimental findings is quite good and it is further improved if a bent structure of the pyrrolidine ring is taken into account. 相似文献
6.
The real characteristic Pontryagin classes of generalized symmetric spaces with simple compact principal Lie groups are calculated in this paper. 相似文献
7.
Pieraccini S Ferrarini A Fuji K Gottarelli G Lena S Tsubaki K Spada GP 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(4):1121-1126
The helical structure of the chiral nematic phases (cholesterics) obtained by doping nematic solvents with chiral non-racemic compounds is a macroscopic proof of the solute chirality. Oligonaphthalene (tetra-, hexa-, octa-) derivatives linked at the 1,4-positions have been used as chiral dopants: When the chirality axes are configurationally homogeneous (that is, all-S), the molecular structures correspond to right-handed helices. Yet, we have found series of derivatives with the surprising property that the handedness of the induced cholesteric phase alternates from positive to negative and to positive again, on passing from tetra- to hexa- and to octanaphthalene. A comparison with oligonapthalene derivatives, which do not exhibit this twisting ability, points to the importance of the substitution pattern. Both the possibility of inducing oppositely-handed cholesteric phases by homochiral helices of different length, and the role played of substituents, are confirmed by calculations performed with the surface chirality model. 相似文献
8.
Bortolus M Parisio G Maniero AL Ferrarini A 《Langmuir : the ACS journal of surfaces and colloids》2011,27(20):12560-12568
We report a combined theoretical and experimental study on the single-molecule interaction of fullerenes with phospholipid membranes. We studied pristine C(60) (1) and two N-substituted fulleropyrrolidines (2 and 3), one of which (3) bore a paramagnetic nitroxide group. Theoretical predictions of fullerene distribution and permeability across lipid bilayers were combined with electron paramagnetic resonance (EPR) experiments in aligned DMPC/DHPC bicelles containing the paramagnetic fulleropyrrolidine 3 or either one of the diamagnetic fullerenes together with spin-labeled lipids. We found that, at low concentrations, fullerenes are present in the bilayer as single molecules. Their preferred location in the membrane is only slightly influenced by the derivatization: all derivatives were confined just below the hydrophilic/hydrophobic interface, because of the key role played by dispersion interactions between the highly polarizable fullerene cage and the hydrocarbon chains, which are especially tight within this region. However, the deviation from spherical shape is sufficient to induce a preferential orientation of 2 and 3 in the membrane. We predict that monomeric fullerenes spontaneously penetrate the bilayer, in agreement with the results of molecular dynamics simulations, but we point out the limits of the currently used permeability model when applied to hydrophobic solutes. 相似文献
9.
Simultaneous Determination of Sulfonamides, Fluoroquinolones, Macrolides and Trimethoprim in Wastewater and River Water by LC-Tandem-MS 总被引:2,自引:0,他引:2
A sensitive and highly selective method for the simultaneous determination of sulfonamides, macrolides, fluoroquinolones and trimethoprim in wastewater and river water has been developed. Samples were enriched by solid-phase extraction and analysed by reversed-phase liquid chromatography coupled to electrospray ionisation tandem mass spectrometry. Several surrogate standards were used for quantification purposes. Absolute recoveries of individual antimicrobials were between 49 and 133% with RSD between 1 and 18% in all investigated matrices. Detection limits in low ng L?1 range were achieved. The method was successfully applied to the analysis of raw municipal wastewater, wastewater effluents and river waters. 相似文献
10.