The superconducting fluctuations well inside the normal state of Fe-based superconductors were studied through measurements of the in-plane paraconductivity and magnetoconductivity in high quality BaFe 2−x Ni x As 2 crystals with doping levels from the optimal level (x = 0.10) up to highly overdoped (x = 0.20). These measurements, performed in magnetic fields up to 9 T perpendicular to the ab (Fe) layers, allowed a reliable check of the applicability to iron-based superconductors of Ginzburg-Landau approaches for 3D anisotropic compounds, even at high reduced temperatures and magnetic fields. Our results also allowed us to gain valuable insight into the dependence on the doping level of some central superconducting parameters (coherence lengths and anisotropy factor).

The superconducting fluctuations well inside the normal state of Fe-based superconductors were experimentally studied through the in-plane paraconductivity in several high-quality, optimally doped BaFe −x 2 Ni x As 2 crystals. These measurements were performed in magnetic fields with amplitudes up to 14 T, and different orientations relative to the c-axis of the crystals (θ = °0 , 53 °, and 90 °). The results allowed a stringent check of the applicability of a recently proposed Ginzburg-Landau approach for the fluctuating electrical conductivity of three-dimensional (3D) anisotropic materials in the presence of finite applied magnetic fields.

It is shown that the magnetization rounding measured by L. Li and coworkers above the superconducting transition in optimally doped YBa2Cu3O 7−δ crystals under magnetic fields up to 14 T [Phys. Rev. B 81, 054510 (2010)] may be explained at a phenomenological level in terms of the mean field Gaussian-Ginzburg-Landau (GGL) approach for layered superconductors. This result challenges the claims of L. Li and coworkers, who write "[...] we are observing the phase-disordering mechanism, rather than Gaussian mean-field fluctuations", but it is in full agreement with earlier magnetization measurements by different authors in optimally-doped YBa2Cu3O 7−δ under lower magnetic fields. The adequacy of the mean-field Ginzburg-Landau descriptions is further confirmed when analyzing the magnetization data reported below Tc by L. Li and coworkers.

Recent studies have shown that blood glutamate grabbing is an effective strategy to reduce the excitotoxic effect of extracellular glutamate released during ischemic brain injury. The purpose of the study was to investigate the effect of two of the most efficient blood glutamate grabbers (oxaloacetate and recombinant glutamate oxaloacetate transaminase 1: rGOT1) in a rat model of intracerebral hemorrhage (ICH). Intracerebral hemorrhage was produced by injecting collagenase into the basal ganglia. Three treatment groups were developed: a control group treated with saline, a group treated with oxaloacetate, and a final group treated with human rGOT1. Treatments were given 1 hour after hemorrhage. Hematoma volume (analyzed by magnetic resonance imaging (MRI)), neurologic deficit, and blood glutamate and GOT levels were quantified over a period of 14 days after surgery. The results observed showed that the treatments used induced a significant reduction of blood glutamate levels; however, they did not reduce the hematoma, nor did they improve the neurologic deficit. In the present experimental study, we have shown that this novel therapeutic strategy is not effective in case of ICH pathology. More importantly, these findings suggest that blood glutamate grabbers are a safe treatment modality that can be given in cases of suspected ischemic stroke without previous neuroimaging. Keywords: blood glutamate grabbing; GOT; intracerebral hemorrhage; oxaloacetate; protection INTRODUCTION Intracerebral hemorrhage (ICH) represents approximately 15% of all strokes; moreover, the incidence of ICH is expected to grow, given the increase in the use of anticoagulants and aging of the population. Journal of Cerebral Blood1 It is a type of acute stroke characterized by extravasation of blood into the brain parenchyma and formation of hematoma. Hematoma produces primary damage because of the toxic effect of thrombin, a mass effect due to the extravasated blood that compresses the surrounding brain tissue; sometimes, this damage is also enhanced by rebleeding. Primary damage is followed by a secondary damage mainly characterized by edema formation, tissular ischemia, and glutamate excitotoxicity.

We study fluctuation conductivity in a single crystal of BaFe 1.9 Ni 0.1 As 2 superconductor (T c = 20 K) as a function of temperature and applied magnetic field. Magneto-conductivity curves, σ versus T, were analyzed in terms of −1/(d ln( σ )/dT) versus T plots, which allow us to study different fluctuation regimes and to estimate exponent values and temperature widths of each regime. The analysis of magneto-conductivity curves evidences the existence of only two fluctuation regimes, a possible critical one (of glass-like type) going from the irreversible temperature to above T c (H), followed by Aslamazov-Larkin fluctuations in the Gaussian regime.