The photosensitive azobenzene-containing
surfactant C
4
-Azo-OC
6
TMAB is a promising agent
for reversible DNA packaging
in a solution. The simulation of the trans-isomer surfactant organization
into associates in a solution with and without salt as well as its
binding to DNA at different NaCl concentrations was carried out by
molecular dynamics. Experimental data obtained by spectral and hydrodynamic
methods were used to verify the results of simulation. It was shown
that head-to-tail aggregates with close to antiparallel orientation
of surfactant molecules were formed at certain NaCl and surfactant
concentrations (below critical micelle concentration). Such aggregates
have two positively charged ends, and therefore, they can be attracted
to negatively charged DNA phosphates far located along the chain,
as well as those that belong to different molecules. This contributes
to the formation of intermolecular DNA–DNA contacts, and this
way, the experimentally observed precipitation of DNA can be explained.
The DNA interaction with cis-isomers of photosensitive azobenzenecontaining surfactants was studied by both experimental methods and computer simulation. It was shown that before the organization of micelles, such surfactants in the cis-conformation form associates of only a single type with a disordered orientation of molecules. In contrast, for trans-isomers, there exist two types of associates with headto-head or head-to-tail orientations of molecules in dependence on salt concentration in a solution. The comparison of cis-and trans-isomer binding to DNA and the influence of salt concentration on the formation of their complexes with DNA were studied. It was shown that cis-isomers interact with phosphate groups of DNA and that their molecules were also located along the minor groove of DNA.
Magnetic Resonance Imaging (MRI) is one of the most widely used medical diagnostic techniques. Digital Imaging and COmmunications in Medicine (DICOM) is standard format to store results of MRI. In the paper methods of visualization of three-dimensional voxel models of human organs from data obtained using MRI are considered. These models may be used both in medical research and for planning of the radiation therapy treatment. The result of the work is a software package developed for medical physics research.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.