Ocrelizumab versus Interferon Beta-1a in Relapsing Multiple Sclerosis

Supported by F. Hoffmann–La Roche

Nucleation and growth phenomena in nanosized electrochemical systems for resistive switching memories

The impact of the electrochemical nucleation on the switching kinetics in many nanoscaled redox-based resistive switching memories is critically discussed. In the case of the atomic switch, the system is site invariant and the nucleation process is strictly localized below the STM tip. Using RbAg4I5 solid electrolyte, nucleation was found to be rate limiting. The electrochemical metallization memory cells (gapless type atomic switch) operate at conditions closer to the conventional nucleation. They introduce additional difficulties for interpretation of the experimental results due to formation of hillocks, of surface oxide barrier films, induction of strain, and the influence of the high electric field. In valence change memories, the nucleation seems to be less important because of the higher applied voltages. The results are discussed in the context of the atomistic theory of electrochemical nucleation. We believe that re-analysis of the experimental data for many systems will reveal that the nucleation is limiting the switching time

Pr x Ba 1-x CoO 3 Oxide Electrodes for Oxygen Evolution Reaction in Alkaline Solutions by Chemical Solution Deposition

Perovskite PrxBa1-xCoO3 (PBCO) thin film electrodes were used in a water splitting electrolysis cell for oxygen evolution reaction (OER) and studied by cyclic voltammetry. We systematically varied the composition of the PBCO deposited by spin-coating using different Ba to Pr ratios. The influence of Pr-content in the perovskite on catalytic OER activity is discussed for two different substrates, namely platinized Si and laser polished Ti. The crystallographic structure of the thin films and the oxidation state of the metal ions in the perovskite is examined by XRD and X-ray photoelectron spectroscopy, respectively. In addition, we propose a laser-polishing process of the Ti substrates as alternative to the classical surface treatment, providing smooth and homogeneous surfaces. Accelerated life time tests have shown the advantage of the catalytically active films deposited on laser polished Ti substrates

Temporal modulation of cerebral hemodynamics under prefrontal challenge in schizophrenia: a transcranial Doppler sonography study

Transcranial Doppler sonography (TCD) is a non-invasive method to assess cerebral blood flow velocity (CBFV) and hence cerebral blood flow during cognitive activation. Major cognitive dysfunctions have been consistently reported in patients with schizophrenia, and important deficits have been observed with respect to prefrontal functions. However, prefrontal activation in schizophrenics has not been investigated with TCD despite its potential to examine short-term changes of cerebral blood flow. The Wisconsin Card Sorting Test (WCST) and the Tower of Hanoi puzzle were administered to 11 right-handed schizophrenics and 20 healthy controls. The middle and anterior cerebral arteries were pairwise insonated. Schizophrenics showed decreased CBFV during the initial phase of both prefrontal functions and the steady-state phase of the Tower of Hanoi. In healthy controls, there was a succession of three significantly different phases of mean CBFV during the Tower of Hanoi, and there was no such modulation in schizophrenics. Immediately after category shift in the WCST, there was an increase of mean CBFV in healthy controls, but not in schizophrenics. In conclusion, transcranial Doppler sonography was able to detect differing specific alterations of CBFV during two prefrontal tasks in healthy controls and patients with schizophrenia. Importantly, the results of this study imply a degraded pattern of CBFV changes over time in schizophrenia during prefrontal activation

Atomically controlled electrochemical nucleation at superionic solid electrolyte surfaces

Electrochemical equilibrium and the transfer of mass and charge through interfaces at the atomic scale are of fundamental importance for the microscopic understanding of elementary physicochemical processes. Approaching atomic dimensions, phase instabilities and instrumentation limits restrict the resolution. Here we show an ultimate lateral, mass and charge resolution during electrochemical Ag phase formation at the surface of RbAg(4)I(5) superionic conductor thin films. We found that a small amount of electron donors in the solid electrolyte enables scanning tunnelling microscope measurements and atomically resolved imaging. We demonstrate that Ag critical nucleus formation is rate limiting. The Gibbs energy of this process takes discrete values and the number of atoms of the critical nucleus remains constant over a large range of applied potentials. Our approach is crucial to elucidate the mechanism of atomic switches and highlights the possibility of extending this method to a variety of other electrochemical systems

Ендоваскуларно лечение на пациенти с остър исхемичен мозъчен инсулт при тромбоза на средна мозъчна артерия – начален опит

Интравенозната тромболиза увеличава вероятността за добър функционален резултат при пациенти с остър исхемичен инсулт. Въпреки това, при част от пациентите, получаващи тромболитично лечение, не се постига желания резултат. Редица скорошни проучвания за механична тромбектомия показват, че това лечение може да бъде по-ефективно от тромболитичното при пациенти с оклузия на голям съд. В сравнение с пациентите, лекувани с медикаменти, пациентите, получили механична тромбектомия и оценени по модифицираната скала на Ранкин е по-вероятно да бъдат функционално независими. Смъртността и симптоматичните вътремозъчни кръвоизливи не се различават значително между двете групи. Механичната тромбектомия значително подобрява функционалната независимост при подходящо подбрани пациенти с остър исхемичен инсулт. Представяме нашите първи 4 случая на ендоваскуларно лечение при пациенти с остър исхемичен мозъчен инсулт в резултат на тромбоза на средна мозъчна артерия

European Stroke Organisation certification of stroke units and stroke centres

To improve quality and to overcome the wide discrepancies in stroke care both within- and between European countries, the European Stroke Organisation Executive Committee initiated in 2007 activities to establish certification processes for stroke units and stroke centres. The rapidly expanding evidence base in stroke care provided the mandate for the European Stroke Organisation Stroke Unit-Committee to develop certification procedures for stroke units and stroke centres with the goals of setting standards for stroke treatment in Europe, improving quality and minimising variation. The purpose of this article is to present the certification criteria and the auditing process for stroke units and stroke centres that aim to standardise and harmonise care for stroke patients, and hence become members of the European Stroke Organisation Stroke Unit and Stroke Centre network. Standardised application forms and guidelines for national and international auditors have been developed and updated by members of the European Stroke Organisation Stroke Unit-Committee. Key features are availability of trained personnel, diagnostic equipment, acute treatment and collaboration with other stroke-caregivers. After submission, the application is reviewed by one national and two international auditors. Based on their reports, the Stroke Unit-Committee will make a final decision. Validating on-site visits for a subset of stroke units and stroke centres are planned. We herein describe a novel, European Stroke Organisation-based online certification process of stroke units and stroke centres. This is a major step forward towards high-quality stroke care across Europe. The additional value by connecting high-quality European Stroke Organisation Stroke Unit and Stroke Centre is facilitation of future collaboration and research activities, enabling building and maintenance of a high-quality stroke care network in Europe. </jats:p

On the stochastic nature of resistive switching in Cu doped Ge0.3Se0.7 based memory devices

Currently, there is great interest in using solid electrolytes to develop resistive switching based nonvolatile memories (RRAM) and logic devices. Despite recent progress, our understanding of the microscopic origin of the switching process and its stochastic behavior is still limited. In order to understand this behavior, we present a statistical "breakdown" analysis performed on Cu doped Ge0.3Se0.7 based memory devices under elevated temperature and constant voltage stress conditions. Following the approach of electrochemical phase formation, the precursor of the "ON resistance switching" is considered to be nucleation - the emergence of small clusters of atoms carrying the basic properties of the new phase which forms the conducting filament. Within the framework of nucleation theory, the observed fluctuations in the time required for "ON resistance switching" are found to be consistent with the stochastic nature of critical nucleus formation. (C) 2011 American Institute of Physics. [doi:10.1063/1.3631013