Main mechanisms and features of epileptogenesis of post-traumatic epilepsy

One of the most frequent and formidable consequences of traumatic brain injury (TBI) is post-traumatic epilepsy (PTE), which is the main identified cause of symptomatic epilepsy at a young age.The work highlights the "trigger" mechanisms of brain damage, including oxidative stress, leading to the disintegration of all levels of the central nervous system, contributing to the development of neuropathological syndromes, and especially PTE.The questions of differentiation of PTE from other epileptic paroxysms, the dependence of the development of PTE on the severity of TBI, the main risk factors for this type of epileptogenesis, its phasing, as well as disorganization and damage to the antiepileptic system are considered. The place of a nonspecific response to damage in the form of immediate and early seizures, their metamorphosis as the formation of PTE was determined.The existing spectrum of convulsive seizures is described, including partial, taking into account the localization characteristic of TBI with a predominance of lezional forms

Influence of magnesium on excitability of neurons of different levels of their organization

AbstractThe article indicates that the hyper-excitability of neurons is associated with ionic imbalance of cell membranes, in which a number of trace elements are involved. The energy component of these processes is associated with the presence of magnesium (Mg) as a universal supplier of the latter. Mg supports the functioning of NMDA receptors, which does not allow the excitotoxic effects of glutamate, which triggers the mechanisms of Ca entry into the neuron and its death, to manifest itself. Mg stimulates the main excitatory neurotransmitter acetylcholine, regulates the release of serotonin, glycine, dopamine, thereby normalizing the extrapyramidal system, the spinal stem structures, and the final executive motor apparatus. Participates in the energy support of adaptation processes, the activation of central regulatory mechanisms, control the excess of catecholamines and corticosteroids, other hormones and mediators involved in stress reactions

Production of exotic isotopes in complete fusion reactions with radioactive beams

The isotopic dependence of the complete fusion (capture) cross section is analyzed in the reactions $^{130,132,134,136,138,140,142,144,146,148,150}$Xe+$^{48}$Ca with stable and radioactive beams. It is shown for the first time that the very neutron-rich nuclei $^{186-191}$W can be reached with relatively large cross sections by complete fusion reactions with radioactive ion beams at incident energies near the Coulomb barrier. A comparison between the complete fusion and fragmentation reactions for the production of neutron-rich W and neutron-deficient Rn isotopes is performed.Comment: 13 pages, 6 figures, accepted in PR

Critical exponents for 3D O(n)-symmetric model with n > 3

Critical exponents for the 3D O(n)-symmetric model with n > 3 are estimated on the base of six-loop renormalization-group (RG) expansions. A simple Pade-Borel technique is used for the resummation of the RG series and the Pade approximants [L/1] are shown to give rather good numerical results for all calculated quantities. For large n, the fixed point location g_c and the critical exponents are also determined directly from six-loop expansions without addressing the resummation procedure. An analysis of the numbers obtained shows that resummation becomes unnecessary when n exceeds 28 provided an accuracy of about 0.01 is adopted as satisfactory for g_c and critical exponents. Further, results of the calculations performed are used to estimate the numerical accuracy of the 1/n-expansion. The same value n = 28 is shown to play the role of the lower boundary of the domain where this approximation provides high-precision estimates for the critical exponents.Comment: 10 pages, TeX, no figure

Critical behavior of three-dimensional magnets with complicated ordering from three-loop renormalization-group expansions

The critical behavior of a model describing phase transitions in 3D antiferromagnets with 2N-component real order parameters is studied within the renormalization-group (RG) approach. The RG functions are calculated in the three-loop order and resummed by the generalized Pade-Borel procedure preserving the specific symmetry properties of the model. An anisotropic stable fixed point is found to exist in the RG flow diagram for N > 1 and lies near the Bose fixed point; corresponding critical exponents are close to those of the XY model. The accuracy of the results obtained is discussed and estimated.Comment: 10 pages, LaTeX, revised version published in Phys. Rev.

Critical behavior of frustrated systems: Monte Carlo simulations versus Renormalization Group

We study the critical behavior of frustrated systems by means of Pade-Borel resummed three-loop renormalization-group expansions and numerical Monte Carlo simulations. Amazingly, for six-component spins where the transition is second order, both approaches disagree. This unusual situation is analyzed both from the point of view of the convergence of the resummed series and from the possible relevance of non perturbative effects.Comment: RevTex, 10 pages, 3 Postscript figure