Biomedical Research Programs at Present and Future High-Energy Particle Accelerators.

Biomedical applications at high-energy particle accelerators have always been an important section of the applied nuclear physics research. Several new facilities are now under constructions or undergoing major upgrades. While the main goal of these facilities is often basic research in nuclear physics, they acknowledge the importance of including biomedical research programs and of interacting with other medical accelerator facilities providing patient treatments.

Effect of mutant NMDA receptors on the oscillations in a model of hippocampus.

A computation approach to identify the effect of missense mutations on the protein function is proposed. Using molecular dynamics simulation we have analyzed the gating kinetics of mutant NMDA synaptic receptors carrying mutations in their NR2 subunits. Analysis of channel geometry and Mg ion binding allowed to estimate the receptor conductivity.

Optimized neuron models for estimation of charged particle energy deposition in hippocampus.

The study of evaluating radiation risk on the central nervous system induced by space-born charged particles is very complex and challenging task in space radiobiology and radiation protection. To overcome computational difficulties in this field, we developed simplified neuron models with properties equivalent to realistic neuron morphology. Three-dimensional structure and parameters of simplified and complex neuron models with realistic morphology were obtained from the experimental data.

Nonlinear dynamics of C-terminal tails in cellular microtubules.

The mechanical and electrical properties, and information processing capabilities of microtubules are the permanent subject of interest for carrying out experiments in vitro and in silico, as well as for theoretical attempts to elucidate the underlying processes. In this paper, we developed a new model of the mechano-electrical waves elicited in the rows of very flexible C-terminal tails which decorate the outer surface of each microtubule. The fact that C-terminal tails play very diverse roles in many cellular functions, such as recruitment of motor proteins and microtubule-associated proteins, motivated us to consider their collective dynamics as the source of localized waves aimed for communication between microtubule and associated proteins.

Modeling nucleotide excision repair and its impact on UV-induced mutagenesis during SOS-response in bacterial cells.

A model of the UV-induced mutation process in Escherichia coli bacteria has been developed taking into account the whole sequence of molecular events starting from initial photo-damage and finishing with the fixation of point mutations. The wild-type phenotype bacterial cells are compared with UV-sensitive repair-deficient mutant cells. Attention is mainly paid to excision repair system functioning as regards induced mutagenesis.

Localized modulated waves in microtubules.

In the present paper, we study nonlinear dynamics of microtubules (MTs). As an analytical method, we use semi-discrete approximation and show that localized modulated solitonic waves move along MT. This is supported by numerical analysis.

Hole-vortex solitons.

Three-dimensional two-component solitons, propagating in long-short wave resonance mode, are predicted. If the spectrum of the short-wave component lies in the area of normal group velocity dispersion, these solitons have transverse structure in the form of hole-vortex field defects on an infinite background. In the opposite case two-component "bullets" or the "bright" vortex and the "bullet" with a hole in the center can exist.