To insert individual citation into a bibliography in a word-processor,
select your preferred citation style below and drag-and-drop it into the document.
This article, adapted from our acceptance speech of the Avanti Award in Lipids at the 47th Biophysical Society meeting in San Antonio, 2003, summarizes over 30 years of research in the area of lipid bilayers. Beginning with a theoretical model of the phase transition (J.F.N.), we have proceeded experimentally using dilatometry and density centrifugation to study volume, differential scanning calorimetry to study heat capacity, and X-ray scattering techniques to study structure of lipid bilayers as a function of temperature. Electron density profiles of the gel and ripple phases have been obtained as well as profiles from several fluid phase lipids, which lead to many structural results that compliment molecular dynamics simulations from other groups. Using the theory of liquid crystallography plus oriented lipid samples, we are the first group to obtain both material parameters (KC and B) associated with the fluctuations in fluid phase lipids. This allows us to use fully hydrated lipid samples, as in vivo, to obtain the structure.
This a summary of the work of the Nagles. In the beginning they measured the volume of the DPPC lipid which changes drastically between the different phase - Lc, Lb, Lp and La. Theoretically they tried to understand the Lp to La transition. Some of the enthalpy is due to expansion against vdW interactions.
Then, they built a statistical mechanics model based on the dimer lattice model, which shows interesting phenomena, different then Ising. (Nagle 1989 - summary).
Next, they studied the Lc to Lb transition - which occurs on cooling at 7C and on heating at 14C. They showed that 14C is the real Tc. The reason for the difference is given by a kinetic theory of nucleation - Kolmogorov-Avrahami theory (Yang and Nagle 1988, Nagle et al . 1998)
In order to research bilayer properties they used the method of deducing from the gel phase to the fluid phase. Using x-ray diffraction they found also the structure of DMPC in a more complicated way (Tristram-Nagle 2002).
The crystalline and ripple phases are still quite unsolved.
(I can read the sources quoted in order to learn more about these phases and X ray).
They measured DOPC in different hydration conditions to obtain better peaks. The reason for the lack of liquid peaks is not normal atomic fluctuations but bilayer fluctuations. The Caille theory and its extensions show the expected diffraction from such a system.
Hydrating oriented bilayers to 100% gave a breakthrough in their research. Differentiating between qr and qz allows determination of S(q) and then calculating F(qz) directly for the fluid phase, not only from the peaks but from the entire data.
Lastly, the say that MC calculation will allow understanding of the role of fluctuation in the interaction between bilayers.
CiteULike organises scholarly (or academic) papers or literature and provides bibliographic
(which means it makes bibliographies) for universities and higher education establishments.
It helps undergraduates and postgraduates. People studying for PhDs or in postdoctoral (postdoc) positions.
The service is similar in scope to EndNote or RefWorks or any other reference manager
like BibTeX, but it is a social bookmarking service for scientists and humanities researchers.
Notes for this article
There are no reviews yet
