Multiple dense phases of nucleosome core particles (NCPs) were formed in controlled ionic conditions (15-160 mM monovalent salt, no divalent ions), under osmotic pressures ranging from 4.7 x 10(5) to 2.35 x 10(6) Pa. We present here the x-ray diffraction analysis of these phases. In the lamello-columnar phase obtained at low salt concentration (<25 mM), NCPs stack into columns that align to for...

X-ray reflectivity (XR) and diffraction at grazing angles of incidence (GID) were conducted to determine the structure of synthetic D-erythro C18-ceramide films at the air-water interface at various surface pressures (pi). Analysis of the GID reveals that the monomolecular film, at the crystalline phase (pi > 0 mN/m), is predominantly hexagonal. In this crystalline phase, the analysis of the re...

Membrane fusion is a ubiquitous process in eukaryotic cells. When two membranes fuse, lipid must undergo molecular rearrangements at the point of merging. To understand how lipid structure transitions occur, scientists studied the phase transition of lipid between the lamellar (L(alpha)) phase and the inverted hexagonal (H(II)) phase, based on the idea that lipid must undergo a similar rearrang...

This thesis is focused on the formation of highly ordered mesoporous structures with adjustable orientation within the ordered, vertical channels of anodic alumina membranes (AAMs) under the conditions of the ‘evaporation-induced self-assembly’ (EISA) method. It is shown that three of the most often used structure directing agents (CTAB, Pluronic123 and Brij56) can be employed for the synthesis...

We have performed ab-initio molecular dynamics simulations to elucidate the mechanism of phase transition at high pressure from hexagonal graphite (HG) diamond (HD) or cubic (CD). The HG HD is found occur swiftly in very small time 0.2 ps, with large cooperative displacements all atoms. observe that alternate layers atoms slide opposite directions by (1/3, 1/6, 0) and (-1/3, -1/6, 0), respectiv...

Although lipid phases are routinely studied by X-ray diffraction, construction of their unit cell structures from the diffraction data is difficult except for the lamellar phases. This is due to the well-known phase problem of X-ray diffraction. Here we successfully applied the multiwavelength anomalous dispersion (MAD) method to solve the phase problem for an inverted hexagonal phase of a phos...

1. 31p NMR is a useful analytical technique for the study of the polymorphic phase behaviour of hydrated phospholipids in excess water. Such possibilities arise due to lateral diffusion of phospholipids which, in non-bilayer phases, produce additional motional averaging mechanisms. This results in distinctive 31p NMR spectra for lipids in the bilayer phase, hexagonal (Hll) phase, or phases such...

The development of new polymerizable lyotropic liquid crystals (LLCs) utilizing charged amphiphilic molecules such as those based on long chain imidazolium compounds, is a relatively new design direction for producing robust membranes with controllable nano-structures. Here we have developed a novel polymerizable ionic liquid based LLC, 1-hexadecyl-3-methylimidazolium acrylate (C16mimAcr), wher...

We report the discovery of a new hexagonal Mo2Ga2C phase, wherein two Ga layers – instead of one – are stacked in a simple hexagonal arrangement in between Mo2C layers. It is reasonable to assume this compound is the first of a larger family.