排序方式: 共有16条查询结果,搜索用时 15 毫秒
1.
Amir H. Bahrami Michael Raatz Jaime Agudo-Canalejo Raphael Michel Emily M. Curtis Carol K. Hall Michael Gradzielski Reinhard Lipowsky Thomas R. Weikl 《Advances in colloid and interface science》2014
How nanoparticles interact with biomembranes is central for understanding their bioactivity. Biomembranes wrap around nanoparticles if the adhesive interaction between the nanoparticles and membranes is sufficiently strong to compensate for the cost of membrane bending. In this article, we review recent results from theory and simulations that provide new insights on the interplay of bending and adhesion energies during the wrapping of nanoparticles by membranes. These results indicate that the interplay of bending and adhesion during wrapping is strongly affected by the interaction range of the particle–membrane adhesion potential, by the shape of the nanoparticles, and by shape changes of membrane vesicles during wrapping. The interaction range of the particle–membrane adhesion potential is crucial both for the wrapping process of single nanoparticles and the cooperative wrapping of nanoparticles by membrane tubules. 相似文献
2.
We consider a theoretical model for membranes with adhesive receptors, or stickers, that are actively switched between two conformational states. In their "on" state, the stickers bind to ligands in an apposing membrane, whereas they do not interact with the ligands in their "off" state. We show that the adhesiveness of the membranes depends sensitively on the rates of the conformational switching process. This dependence is reflected in a resonance at intermediate switching rates, which can lead to large membrane separations and unbinding. Our results may provide insights into novel mechanisms for the controlled adhesion of biological or biomimetic membranes. 相似文献
3.
Multicomponent membranes such as ternary mixtures of lipids and cholesterol can exhibit coexistence regions between two liquid phases. When such membranes adhere to a corrugated substrate, the phase separation process strongly depends on the interplay between substrate topography, bending rigidities, and line tension of the membrane domains as we show theoretically via energy minimization and Monte Carlo simulations. For sufficiently large bending rigidity contrast between the two membrane phases, the corrugated substrate truncates the phase separation process and leads to a stable pattern of membrane domains. Our theory is consistent with recent experimental observations and provides a possible control mechanism for domain patterns in biological membranes. 相似文献
4.
The simultaneous application of pure rotational coherent anti-Stokes Raman spectroscopy (CARS) and vibrational linear Raman spectroscopy (LRS) for the measurement of temperature and species concentrations in combustion systems is demonstrated. In addition to the standard rotational CARS experimental setup, only one detection system (spectrometer and intensified CCD camera) for the collection of the LRS signals was applied. The emission of the broadband dye laser used for CARS was shifted to the deep red to avoid interferences with the LRS signals located in the visible region. First experimental results from a vaporizing propane spray using an engine injection system are shown. 相似文献
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6.
The behavior of two membranes that interact by active
adhesion molecules or stickers is studied theoretically using
mean-field theory and Monte Carlo simulations. The stickers are
anchored in one of the membranes and undergo conformational
transitions between on and off states. In their on states, the
stickers can bind to ligands that are anchored in the other
membrane. The transitions between the on and off states arise
from the coupling of the stickers to some active,
energy-releasing process, which keeps the system out of
equilibrium. As one varies the transition rates of this active
process, the membrane separation undergoes a stochastic
resonance: this separation is maximal at intermediate rates of
the sticker transitions and considerably smaller both at high and
at low transition rates. This implies that the effective,
fluctuation-induced repulsion between the membranes contains a
rate-dependent contribution that arises from the switching of the
active stickers. 相似文献
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8.
Weikl TR Andelman D Komura S Lipowsky R 《The European physical journal. E, Soft matter》2002,8(1):59-66
Biomimetic membranes in contact with a planar substrate or a second membrane are studied theoretically. The membranes contain
specific adhesion molecules (stickers) which are attracted by the second surface. In the absence of stickers, the trans-interaction
between the membrane and the second surface is assumed to be repulsive at short separations. It is shown that the interplay
of specific attractive and generic repulsive interactions can lead to the formation of a potential barrier. This barrier induces
a line tension between bound and unbound membrane segments which results in lateral phase separation during adhesion. The
mechanism for adhesion-induced phase separation is rather general, as is demonstrated by considering two distinct cases involving:
i) stickers with a linear attractive potential, and ii) stickers with a short-ranged square-well potential. In both cases,
membrane fluctuations reduce the potential barrier and, therefore, decrease the tendency of phase separation.
Received 24 January 2002 and Received in final form 24 April 2002 相似文献
9.
M.C. Weikl T. Seeger R. Sommer A. Leipertz 《Proceedings of the Combustion Institute》2009,32(1):745-752
In this work, an emission spectroscopic (ES) technique for the determination of soot temperatures in an axisymmetric flame is validated against coherent anti-Stokes Raman spectroscopy (CARS) as preparation for a zero gravity measurement campaign. In order to reduce valuable measurement times during the parabolic flights, a setup for spatially resolved one-dimensional measurements along a line has been built up using an imaging spectrometer and a CCD-camera for data acquisition.In order to assess the performance of the ES technique, accurate coherent anti-Stokes Raman scattering (CARS) measurements have been performed at the same conditions. Hereby, great care has to be taken to minimize the known interferences in sooting flames. The non-resonant signal contribution was suppressed by a polarization technique and the signal wavelength was shifted to an interference free region. These modifications are discussed in detail. The temperatures obtained by both methods are in good agreement in most regions of the flame. It turned out that the described approach for ES is an appropriate and robust alternative for measuring temperatures in sooting axisymmetric flames, if more accurate techniques cannot be applied, e.g., during investigations in zero-g parabolic flight experiments. 相似文献
10.
Andreas?Lüthi Martin?A?Wikstr?m Mary?J?Palmer Paul?Matthews Tim?A?Benke John?TR?Isaac Graham?L?CollingridgeEmail author 《BMC neuroscience》2004,5(1):44