Asymmetric Lineshape due to Inhomogeneous Broadening of the Crystal-Field Transitions in Mn12ac Single Crystals

The lineshape of crystal-field transitions in single crystals of Mn12ac molecular magnets is determined by the magnetic history. The absorption lines are symmetric and Gaussian for the non-magnetized state obtained by zero-field cooling (zfc). In the magnetized state which is reached when the sample is cooled in a magnetic field (fc), however, they are asymmetric even in the absence of an external magnetic field. These observations are quantitatively explained by inhomogeneous symmetrical (Gaussian) broadening of the crystal-field transitions combined with a contribution of off-diagonal components of the magnetic susceptibility to the effective magnetic permeability.Comment: 4 pages, 3 figure

COGNITIVE EPILEPTIFORM DISINTEGRATION: DEFINITION, DIAGNOSIS, THERAPY

Cognitive epileptiform disintegration — symptom complex of acquired disorders of cognitive functions in children, associated with marked epileptiform activity on EEG in the absence of epileptic seizures (isolated epileptic seizures in the medical history are possible). On background of review and discussion of current scientific literature and own data the author represents the fundamental article, devoted to cognitive epileptiform disintegration. The author describes in detail the aspects of definition, aetiology and pathogenesis, diagnostic criteria and differential diagnostics of this disorder, and approaches to the treatment. As the main factors of aetiology and pathogenesis the author describes the role of hereditary impairment of brain maturation and pathologic effects of continuous prolonged epileptiform activity on cognitive functions, as well as morphologic alterations (lesion) of the brain, caused by pathology of prenatal period. The clinical features of cognitive epileptiform disintegration depending on predominance localization of epileptiform activity in different areas of brain cortex are discussed. The especial attention is given to approaches to the treatment of cognitive epileptiform disintegration (approaches to the treatment of seizures and cognitive disorders are discussed separately). Efficacy of valproates, corticosteroid hormones and antiepileptic drugs of other groups is considered and assessed

Dynamical mean field theory for manganites

Doped and undoped manganites are modeled by the coupling between itinerant $e_g$ electrons and static $t_{2g}$ spins, the Jahn-Teller and breathing phonon modes, and the Coulomb interaction. We provide for a careful estimate of all parameters and solve the corresponding Hamiltonian by dynamical mean field theory. Our results for the one-electron spectrum, the optical conductivity, the dynamic and static lattice distortion, as well as the Curie temperature show the importance of all of the above ingredients for a realistic calculation as well as for describing the unusual dynamical properties of manganites including the insulating parent compound and the insulating-like paramagnetic state of doped manganites.Comment: 11 pages, 18 figures In the 2nd version the only change is to correct one (important) referenc

Quantum spin chains and integrable many-body systems of classical mechanics

This note is a review of the recently revealed intriguing connection between integrable quantum spin chains and integrable many-body systems of classical mechanics. The essence of this connection lies in the fact that the spectral problem for quantum Hamiltonians of the former models is closely related to a sort of inverse spectral problem for Lax matrices of the latter ones. For simplicity, we focus on the most transparent and familiar case of spin chains on N sites constructed by means of the GL(2)-invariant R-matrix. They are related to the classical Ruijsenaars-Schneider system of N particles, which is known to be an integrable deformation of the Calogero-Moser system. As an explicit example the case N=2 is considered in detail.Comment: 17 pages, misprints corrected, written for Proceedings of the International School and Workshop "Nonlinear Mathematical Physics and Natural Hazards", Sofia, Bulgaria, November 28 - December 2, 2013, to be published in Lecture Notes in Physic

Some recursive formulas for Selberg-type integrals

A set of recursive relations satisfied by Selberg-type integrals involving monomial symmetric polynomials are derived, generalizing previously known results. These formulas provide a well-defined algorithm for computing Selberg-Schur integrals whenever the Kostka numbers relating Schur functions and the corresponding monomial polynomials are explicitly known. We illustrate the usefulness of our results discussing some interesting examples.Comment: 11 pages. To appear in Jour. Phys.

RUFINAMIDE (INOVELON) IN THE TREATMENT OF LENNOX–GASTAUT SYNDROME (A REVIEW OF LITERATURE AND CLINICAL CASE)

Lennox–Gastaut syndrome (LGS) is childhood-onset epileptic encephalopathy manifested by frequent polymorphic seizures, including tonic axial, obvious cognitive impairments, characteristic ECG changes, and therapeutic resistance. Due to the concurrence of several types of seizures in the clinical presentation of the disease and their resistance to drug therapy, great hopes are pinned on the design of novel antiepileptic drugs with fundamentally other mechanisms of action and aimed specially at treating this severe type of epilepsy. The authors review the foreign literature on the new antiepileptic drug rufinamide (Inovelon) registered in Russia in January 2015 to directly treat LGS as adjunctive treatment in children 4 years and older and adults. Multiple trials have demonstrated that rufinamide has efficacy and good tolerability in treating LGS.The authors describe an observed case of the efficacy of rufinamide in a 17-year-old male patient with LGS. Despite the drug resistance of epilepsy and no response to multiple antiepileptic drugs used alone and in different combinations, the incorporation of rufinamide into a treatment regimen had a pronounced therapeutic effect: the frequency of convulsive seizures decreased by 70 %. At the time of writing this paper, the patient has been receiving rufinamide for more 5 months. He has been tolerating the therapy well

Epileptic spasms: Nosological characteristics and approaches to therapy

Objective: to study the incidence, anamnestic, clinical, electroencephalographic, and neuroimaging features of epileptic syndromes associated with epileptic spasms (ES) and the efficiency of antiepileptic therapy in patients with these conditions. Patients and methods. The study covered 1261 patients with epileptic seizures in the history with their onset from the first day of life to 18 years.Results. A history of ES was recorded in 112 patients, which accounted for 8.9% of cases among all the forms of epilepsy with its onset less than 18 years of age. ES was detected in 47.1% of the patients with seizure onset in the first year of life. There was a slight male preponderance: 59 (52.7%) versus 53 (47.3%). Epilepsy with ES onset occurred in the first 6 months of life in 57.9% of cases. The West syndrome was found in 58.9% of the patients with ES-associated epilepsy, which amounted to 5.2% of all forms of epilepsy developing at the age of less than 18 years; Ohtahara syndrome in 32.1% (2.9% of all forms of epilepsy), early myoclonic encephalopathy in 0.9% (0.08%) and symptomatic focal epilepsy with periodic spasms in 8.1% (0.7% of all forms of epilepsy). Antiepileptic therapy led to complete remission in 45.5% of ES-associated epilepsy cases. There was a 50% or more reduction in the rate of seizures in 35.7% of the patients treated with antiepileptic drugs. No effect was seen in 18.8% of cases