A new spectroscopic research for radiation damage to DNA and related molecules is proposed, which is made possible using a liquid micro-jet technique for bio-solution under vacuum in combination with site-selective excitation using a soft X-ray synchrotron radiation. Described is the present state of research on the selective primary radiation interaction onto base moieties of nucleotides. Spectra of X-ray absorption near edge structure (XANES) at energies around the nitrogen K-edge for nucleotides in aqueous solutions are presented. Selective excitation of a base moiety using a soft X-ray synchrotron radiation allows us to investigate the interaction of the base moiety with water solvent. We discuss the change of spectral character of XANES which reveals to the structural change of the base moiety under different pH condition of solution. A new scope for cooperative direct and indirect primary radiation effets is given.
Atoms and molecules move along a gradient of external fields as seen in electrophoresis, which is a motion of charged molecules relative to fluid along an electric field. One unexplored but relevant alternative is thermophoresis, the Ludwig-Soret effect, that makes a solute moves along a temperature gradient. Thermophoresis depletes a polyethylene (PEG) polymer of large concentrations from the hot region and builds a concentration gradient. In such a solution, solutes of small concentration experience thermophoresis and PEG concentration-dependent restoring forces. Under focused laser heating, DNA and RNA as solutes localize as a ring-like structure which diameter monotonically decreases with the size of polymer following a behavior analogous to gel electrophoresis. Thus trapping and separation of biopolymers could be physically feasible in a simple way relying on temperature gradient. Moreover, since this effect relies on the entropic force in a PEG concentration gradient, trapping with little material dependence is feasible for bacteria and motile eukaryotic cells. It may bring new method to control the density of living cells and biopolymers with light.
It is known that topological string theory is related to integrable systems. This fact allows us to solve an integrable system by using results in the corresponding topological string. We show that the eigenvalue problem for a class of quantum integrable systems, including the relativistic Toda lattice, is indeed solved by the topological strings. It turns out that the obtained quantization conditions have a non-trivial strong-weak duality with respect to the Planck constant.
Here, we have studied the performance of an entanglement sensor under the effect of non-Markovian dephasing that is the dominant source of decoherence in solid-state systems. We have shown that one can actually sense a magnetic field with an accuracy far beyond the classical limit in realistic conditions. Our scheme could pave the way to realize a practical entanglement sensor.