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101.
Water at biomolecular binding interfaces 总被引:2,自引:0,他引:2
Water molecules are often found at the binding interface of biomolecular complexes mediating the interaction between polar groups via hydrogen bonds, or simply filling space providing van der Waals interactions. Recent studies have demonstrated the importance of taking such water molecules into account in docking and binding affinity prediction. Here, we review the recent experimental and theoretical work aimed at quantifying the influence of interfacial water on the thermodynamic properties of binding. We highlight especially our recent results obtained by inhomogeneous fluid solvation theory in several systems and the prediction of the thermodynamic consequences of displacement of the bound water molecule by ligand modification. Finally, we discuss possible directions for further progress in this field. 相似文献
102.
Tofi M Montagnon T Georgiou T Vassilikogiannakis G 《Organic & biomolecular chemistry》2007,5(5):772-777
Singlet oxygen (1O2) proves to be a powerful tool in mediating the one-pot synthesis of a salinomycin-type [6,6,5]-bis-spiroketal unit starting from a suitably substituted furan nucleus. 相似文献
103.
Sotiropoulou M Bossard F Balnois E Oberdisse J Staikos G 《Langmuir : the ACS journal of surfaces and colloids》2007,23(22):11252-11258
The formation of soluble hydrogen-bonding interpolymer complexes between poly(acrylic acid) (PAA) and poly(acrylic acid-co-2-acrylamido-2-methyl-1-propane sulfonic acid)-graft-poly(N,N-dimethylacrylamide) (P(AA-co-AMPSA)-g-PDMAM) at pH=2.0 was studied. A viscometric study showed that in semidilute solution a physical gel is formed due to the interconnection of the anionic P(AA-co-AMPSA) backbone of the graft copolymer, in a transient network, by means of the complexes formed between the PDMAM side chains of the graft copolymer and PAA. Dynamic and static light scattering measurements, in conjunction with small-angle neutron scattering measurements, suggest the formation of core-shell colloidal nanoparticles in dilute solution, comprised by an insoluble PAA/PDMAM core surrounded by an anionic P(AA-co-AMPSA) corona. Even if larger clusters are formed in semidilute solution, the size of the insoluble core remains practically stable. Atomic force microscopy performed under ambient conditions reveal that the particles collapse and flatten upon deposition on a substrate, with dimensions close to the ones of the dry hydrophobic core. 相似文献
104.
Georgios Patermarakis Konstantinos Moussoutzanis Nikolaos Nikolopoulos 《Journal of Solid State Electrochemistry》1999,3(4):193-204
A new method has been developed capable of describing the incorporation of electrolyte anions along the pore wall surface
and across both the barrier layer and the pore wall oxide after the establishment of the steady state of growth of porous
anodic Al2O3 where other methods cannot be applied to obtain reliable results. The knowledge of the nature/composition of anodic oxides
as regards the incorporation of species like electrolyte anions is of specific importance for both the understanding of the
electrochemical mechanism of oxide production and growth and the scientific and technological applications of porous anodic
Al2O3 films. The method consists of the selection and use of a suitable catalytic probe reaction on porous anodic oxides at thicknesses
varying from a value near zero up to the maximum limiting thickness and the treatment of the experimental reaction rate results
by a properly developed mathematical formalism. This method was employed in anodic Al2O3 films prepared in H2SO4 anodizing electrolyte at a constant bath temperature and different current densities using as a probe reaction the decomposition
of HCOOH on these oxides, which is almost exclusively a dehydration reaction, at relatively high reaction temperatures, 350 °C
and 390 °C, where the effect of other species except SO4
2− incorporated in the oxide on the reaction rate is eliminated. It has been shown that the fraction of the intercrystallite
surfaces occupied by SO4
2− follows a parabola-like distribution. It has a significant value at the pore base surface, depending on the current density,
then it passes through a maximum along the pore wall surface and across both the barrier layer and the pore walls near the
pore bases at positions depending on the current density and then becomes almost zero at the mouths of the pores of the oxide
with the maximum limiting thickness and at both the Al2O3/Al interface and cell boundaries. The maximum value of the surface coverage is almost independent of the current density
and is always near 1, showing an almost complete saturation of intercrystalline surfaces at these positions. The above distribution
of surface coverage predicts a qualitatively similar distribution of the SO4
2− bulk concentration across both the barrier layer and pore wall oxide around the pore bases. The method may be improved and
developed further either for a more detailed investigation of the above films or to investigate films prepared in other pore-forming
electrolytes.
Received: 30 July 1998 / Accepted: 30 September 1998 相似文献
105.
106.
Ioannis Martakos Panagiota Katsianou Georgios Koulis Elvira Efstratiou Eleni Nastou Stylianos Nikas Marilena Dasenaki Michalis Pentogennis Nikolaos Thomaidis 《Molecules (Basel, Switzerland)》2021,26(23)
In this study, an overall survey regarding the determination of several bioactive compounds in olive fruit is presented. Two methodologies were developed, one UPLC-Q-TOF-MS method for the determination of olive fruit phenolic compounds and one HPLC-DAD methodology targeting the determination of pigments (chlorophylls and carotenoids), tocopherols (α-, β, -γ, δ-) and squalene. Target and suspect screening workflows were developed for the thorough fingerprinting of the phenolic fraction of olives. Both methods were validated, presenting excellent performance characteristics, and can be used as reliable tools for the monitoring of bioactive compounds in olive fruit samples. The developed methodologies were utilized to chemical characterize the fruits of the Kolovi olive variety, originating from the island of Lesvos, North Aegean Region, Greece. Twenty-five phenolic compounds were identified and quantified in Kolovi olives with verbascoside, hydroxytyrosol, oleacein and oleomissional found in significantly high concentrations. Moreover, 12 new bioactive compounds were identified in the samples using an in-house suspect database. The results of pigments analysis suggested that Kolovi variety should be characterized as low pigmentation, while the tocopherol and squalene content was relatively high compared to other olive varieties. The characterization of Kolovi olive bioactive content highlighted the high nutritional and possible economic value of the Kolovi olive fruit. 相似文献
107.
Pandelitsa?Panaseti Anne-Laure?Vayssade Georgios?C.?GeorgiouEmail author Michel?Cloitre 《Rheologica Acta》2017,56(6):539-553
The steady, pressure-driven flow of a Herschel-Bulkley fluid in a microchannel is considered, assuming that different power-law slip equations apply at the two walls due to slip heterogeneities, allowing the velocity profile to be asymmetric. Three different flow regimes are observed as the pressure gradient is increased. Below a first critical pressure gradient G 1, the fluid moves unyielded with a uniform velocity, and thus, the two slip velocities are equal. In an intermediate regime between G 1 and a second critical pressure gradient G 2, the fluid yields in a zone near the weak-slip wall and flows with uniform velocity near the stronger-slip wall. Beyond this regime, the fluid yields near both walls and the velocity are uniform only in the central unyielded core. It is demonstrated that the central unyielded region tends towards the midplane only if the power-law exponent is less than unity; otherwise, this region rends towards the weak-slip wall and asymmetry is enhanced. The extension of the different flow regimes depends on the channel gap; in particular, the intermediate asymmetric flow regime dominates when the gap becomes smaller than a characteristic length which incorporates the wall slip coefficients and the fluid properties. The theoretical results compare well with available experimental data on soft glassy suspensions. These results open new routes in manipulating the flow of viscoplastic materials in applications where the flow behavior depends not only on the bulk rheology of the material but also on the wall properties. 相似文献
108.
We find exact solutions of the two- and three-dimensional nonlinear Schrödinger equation with a supporting potential. We focus in the case where the diffraction operator is of the hyperbolic type and both the potential and the solution have the form of an X-wave. Following similar arguments, several additional families of exact solutions can also can be found irrespectively of the type of the diffraction operator (hyperbolic or elliptic) or the dimensionality of the problem. In particular we present two such examples: The one-dimensional nonlinear Schrödinger equation with a stationary and a “breathing” potential and the two-dimensional nonlinear Schrödinger with a Bessel potential. 相似文献
109.
Georgios Veronis Zongfu Yu Sukru Ekin Kocabas David A. B. Miller Mark L. Brongersma Shanhui Fan 《中国光学快报(英文版)》2009,7(4)
We review some of the recent advances in the development of subwavelength plasmonic devices for ma- nipulating light at the nanoscale, drawing examples from our own work in metal-dielectric-metal (MDM) plasmonic waveguide devices. We introduce bends, splitters, and mode converters for MDM waveguides with no additional loss. We also demonstrate that optical gain provides a mechanism for on/off switch- ing in MDM plasmonie waveguides. Highly efficient compact couplers between dielectric waveguides and MDM waveguides are also introduced. 相似文献
110.
The vapor–liquid equilibria of binary polymer–solvent systems was modeled using the Non-Random Hydrogen Bonding (NRHB) model. Mixtures of poly(ethylene glycol), poly(propylene glycol), poly(vinyl alcohol) and poly(vinyl acetate) with various solvents were investigated, while emphasis was put on hydrogen bonding systems, in which functional groups of the polymer chain can self-associate or cross-associate with the solvent molecules. Effort has been made to explicitly account for all hydrogen bonding interactions. The results reveal that the NRHB model offers a flexible approach to account for various self- or cross-associating interactions. In most cases model's predictions (using no binary interaction parameter kij = 0) and model's correlations (using one temperature independent binary interaction parameter, kij ≠ 0) are in satisfactory agreement with the experimental data, despite the complexity of the examined systems. 相似文献