Studies of Galatea Multipole Traps at the Russian Technoligical University MIREA

Plasma Physics Reports - Results from studies of plasma production and confinement in Galatea multipole magnetic traps at the Russian Technological University MIREA are presented. The magnetic...     

Application of the Morozov–Solov’ev Equations to a Toroidal Magnetic Trap

Plasma Physics Reports - In 1974, A.I. Morozov and L.S. Solov’ev derived a general system of time-independent equations of two-component ideal plasma hydrodynamics [1]. This system is...     

Preparation of cell walls of group A Streptococcus. Methods of disintegration, isolation and control]

A method for disintegration of cells of group A streptococcus on the Edebeau extrusion press was developed. The level of disintegration was controlled by cell count in stained preparations, Coultier electronic counter and electron microscope. The streptococcus cell disintegration in the Edebeau extrusion press at a temperature of --40 degrees, a pressure of 3200 kg/cm2 and two cycles of the process was completed by 96-98%.     

Effect of concentrations of limiting substrates on the linear growth rates of Streptomyces levoris colonies

The relationship between linear growth rates of S. levoris zone-forming colonies and concentrations of different limiting energy and carbon sources in the nutrient medium has been studied. A formula has been derived satisfactorily describing this relationship. The utilization of the substrates in the source of vegetative and reproductive processes as well as possible mechanisms controlling the periodicity in the life activities of streptomyces colonies are discussed.     

Preparing Modified Hyaluronic Acid with Tunable Content of Vinyl Groups for Use in Fabrication of Scaffolds by Photoinduced Crosslinking

Russian Journal of Bioorganic Chemistry - Materials based on hyaluronic acid (HA) are extensively used in tissue engineering as scaffolds. Photoinduced crosslinking is one way to prepare them, and,...     

Molecular Renormalization Group Coarse-Graining of Polymer Chains: Application to Double-Stranded DNA

Coarse-graining of atomistic force fields allows us to investigate complex biological problems, occurring at long timescales and large length scales. In this work, we have developed an accurate coarse-grained model for double-stranded DNA chain, derived systematically from atomistic simulations. Our approach is based on matching correlators obtained from atomistic and coarse-grained simulations, for observables that explicitly enter the coarse-grained Hamiltonian. We show that this requirement leads to equivalency of the corresponding partition functions, resulting in a one-step renormalization. Compared to prior works exploiting similar ideas, the main novelty of this work is the introduction of a highly compact set of Hamiltonian basis functions, based on molecular interaction potentials. We demonstrate that such compactification allows us to reproduce many-body effects, generated by one-step renormalization, at low computational cost. In addition, compact Hamiltonians greatly increase the likelihood of finding unique solutions for the coarse-grained force-field parameter values. By successfully applying our molecular renormalization group coarse-graining technique to double-stranded DNA, we solved, for the first time, a long-standing problem in coarse-graining polymer systems, namely, how to accurately capture the correlations among various polymeric degrees of freedom. Excellent agreement is found among atomistic and coarse-grained distribution functions for various structural observables, including those not included in the Hamiltonian. We also suggest higher-order generalization of this method, which may allow capturing more subtle correlations in biopolymer dynamics.