Myo-Inositol Limits Kainic Acid-Induced Epileptogenesis in Rats

Epilepsy is a severe neurological disease characterized by spontaneous recurrent seizures (SRS). A complex pathophysiological process referred to as epileptogenesis transforms a normal brain into an epileptic one. Prevention of epileptogenesis is a subject of intensive research. Currently, there are no clinically approved drugs that can act as preventive medication. Our previous studies have revealed highly promising antiepileptogenic properties of a compound–myo-inositol (MI) and the present research broadens previous results and demonstrates the long-term disease-modifying effect of this drug, as well as the amelioration of cognitive comorbidities. For the first time, we show that long-term treatment with MI: (i) decreases the frequency and duration of electrographic SRS in the hippocampus; (ii) has an ameliorating effect on spatial learning and memory deficit associated with epileptogenesis, and (iii) attenuates cell loss in the hippocampus. MI treatment also alters the expression of the glial fibrillary acidic protein, LRRC8A subunit of volume-regulated anion channels, and protein tyrosine phosphatase receptor type R, all expected to counteract the epileptogenesis. All these effects are still present even 4 weeks after MI treatment ceased. This suggests that MI may exert multiple actions on various epileptogenesis-associated changes in the brain and, therefore, could be considered as a candidate target for prevention of epileptogenesis.     

Mixed-State Specific Heat of the Type-II Superconductor Nb0.77Zr0.23 in Magnetic Fields up toB c2

In order to document the behavior of the mean-field mixed-state specific heat of an isotropic. strongly type-II superconductor (i.e., with a large value of the Ginzburg parameterk), and to provide a basis for comparison with high-temperature superconductors, we measured the specific heatC of the alloy Nb_0.77Zr_0.23 withT _c = 10.8K, B _c2 (0) = 7.9T, in magnetic fieldsB = 0, 0.2, 1.0, 12, 2.0, 2.4. 3.0, 3.3. 4.0. 4.4, 4.8, 5.2, 6.0. 6.6, 7.2 and 10 T. The values of the upper critical fieldB _c2 ( T), thermodynamic critical fieldB _c (T), Ginzburg parameterk(T), and coefficient γ(B) = lim_{T0(C(T. B)/T)} are derived from the specific heat data and found to be in agreement with the GLAG theory in the dirty limit. The behavior of the mixed-state specific heat is analyzed in terms ofC _el /T,∂(C _el /T)/∂B, and∂(C _el /T)/∂T vs. Tcurves, whereC _el is the electronic contribution to the specific heat.     

From SrCuO2 to Sr8Cu8O20−y: Why Are Superconducting Properties of Infinite-Layer Compounds so Poor?

A series of infinite-layer compounds Nd _x Sr_1?x CuO₂ were synthesized by high-pressure technique under different pressure, temperature, and time conditions. Crystal structure, microstructure, and superconducting properties of the samples obtained were systematically investigated as a function of the synthesis conditions. The stability of the IL phase was studied using annealing procedures in Ar- and O₂-flow, as well as under oxygen pressure up to 90 bar followed by thermogravimetric, energy-dispersive X-ray analysis, and X-ray diffraction measurements. On the basis of the results obtained we suggest a decomposition mechanism for the infinite-layer phase, which is responsible for the degradation of T _c , as well as a routine to produce electron-doped infinite-layer compounds with a sharp diamagnetic signal of bulk superconductivity.     

From SrCuO2 to Sr8Cu8O20?y: Why Are Superconducting Properties of Infinite-Layer Compounds so Poor?

A series of infinite-layer compounds Nd _x Sr_1–x CuO₂ were synthesized by high-pressure technique under different pressure, temperature, and time conditions. Crystal structure, microstructure, and superconducting properties of the samples obtained were systematically investigated as a function of the synthesis conditions. The stability of the IL phase was studied using annealing procedures in Ar- and O₂-flow, as well as under oxygen pressure up to 90 bar followed by thermogravimetric, energy-dispersive X-ray analysis, and X-ray diffraction measurements. On the basis of the results obtained we suggest a decomposition mechanism for the infinite-layer phase, which is responsible for the degradation of T _c , as well as a routine to produce electron-doped infinite-layer compounds with a sharp diamagnetic signal of bulk superconductivity.     

Oxygen doping and temperature dependence of the tunneling spectroscopy on Bi2Sr2CaCu2O8+δ

We present local probe tunneling spectroscopy of Bi₂Sr₂CaCu₂O₈₊ single crystals for different oxygen concentrations, from optimally doped (T_c=92.2 K) to highly overdoped (T_c=56.0 K) phases. With increasing oxygen overdoping, the superconducting gap (_p) is reduced and the dip structure beyond _p at negative sample bias¹ shifts toward the Fermi energy. Apart from the shift in energy of these features, the generic shape of the tunneling spectra remains unchanged. The gap roughly scales with T_c, and 2_p/k_BT_c stays large even in the highly overdoped phase. We also present preliminary results on the temperature dependence of the tunneling spectra. They are consistent with a gap that is largely independent on temperature up to the vicinity of T_c