The characterization of hexagonal lyotropic liquid crystal nanostructure: effects of polymer tail length

The hexagonal phase, which is one of the lyotropic liquid crystal phases, is used as a soft template in nanotechnology. In lyotropic liquid crystals, mesophases arise as a result of the balance of the delicate interactions of components. Understanding and using these delicate interaction balances can be advantageous for arranging soft templates. Polymer of different chain lengths was added to the samples showing hexagonal phase that emerged in SDS + water binary mixture. How hexagonally clustered surfactants in SDS + water + PVP mixture were affected by the presence of polymer in tail and head groups was investigated through FTIR analysis. On the other hand, SAXS analyses provide information about structural parameters. The interactions between polymer chains and surfactant chains in the presence of polymer changed the lattice parameter of the hexagonal phase and the width of the water channels between the hexagonal packages. As a result of the examination, it was determined that the long- and short-chain polymers affected the structural parameters of the hexagonal phase differently

Boolean gene regulatory network model of centromere function in Saccharomyces cerevisiae

WOS: 000482390100001PubMed ID: 31175490Centromeres, a highly conserved locus of eukaryotic chromosomes, have critical function for genome stability and integrity. Because their centromeric DNA sequences are necessary and sufficient for kinetochore recruitment and DNA segregation, point centromeres of Saccharomyces cerevisiae chromosomes provide an attractive system for the study of the regulation of centromere function. Using the mathematical model of Boolean gene regulatory networks, the gene regulatory dynamics of centromere region of S. cerevisiae (budding yeast), which is actively involved in the cell-cycle, has been examined. A gene regulatory network containing the relevant centromere genes of the model organism from biological databases was established and all possible cellular phenotypes subjected to a synchronous gene regulation and attracted to several basins. Gene expression in the largest attractor was compared with the biological data by obtaining changes in the cell-cycle. We show that the model for centromere function recovers a single cyclic attractor. The trajectory flow diagram plotted over all initial conditions of the system also shows good correspondence with the cell-cycle phases. Although other upstream signals are possibly involved in the regulation of centromere genes, proposed interactions with selected cell-cycle genes were sufficient to recover whole cell-cycle process. To truly clarify these proposed regulatory interactions of candidate genes for centromere function, profiling and analyzing their expression levels over time with expanded nodes/edges are required. Moreover, a previously modeled gene knock-down mechanism applied to the network and robustness versus knock-down was interpreted based on the obtained consequences.[2016FEN031]We would thank the project 2016FEN031 for the present study. The authors would also like to thank the anonymous referees for valuable comments and suggestions

Phase diagram of tetradecyltrimethylammonium bromide (TTAB) plus water plus octanol system with application of mechanical deformation

9th Nanoscience and Nanotechnology Conference (NANOTR) -- JUN 24-28, 2013 -- Erzurum, TURKEYWOS: 000344380500044Morphological properties of tetradecyltrimethylammonium bromide (TTAB) + water + octanol system in different concentrations have been studied. In the process, isotropic phase (L-1) and nematic calamitic (N-C) nematic discotic (N-D), hexagonal E and lamellar D anizotropic mesophases have been determined by polarizing microscopy method and partial ternary phase diagram of the system set up. Textural properties of the anisotropic mesophases of the system have been discussed and their birefringence values measured. Mechanical deformation has been applied to the mesophases. The textural properties and the birefringence values have been observed to be changed by the deformation, after and before which changes have been compared. (C) 2014 Elsevier B.V. All rights reserved