Tohoku University

About: Tohoku University is a education organization based out in Sendai, Japan. It is known for research contribution in the topics: Magnetization & Population. The organization has 72116 authors who have published 170791 publications receiving 3941714 citations. The organization is also known as: Tōhoku daigaku.

Towards ultrahigh volumetric capacitance: graphene derived highly dense but porous carbons for supercapacitors

Abstract: A small volumetric capacitance resulting from a low packing density is one of the major limitations for novel nanocarbons finding real applications in commercial electrochemical energy storage devices Here we report a carbon with a density of 158 g cm(-3), 70% of the density of graphite, constructed of compactly interlinked graphene nanosheets, which is produced by an evaporation-induced drying of a graphene hydrogel Such a carbon balances two seemingly incompatible characteristics: a porous microstructure and a high density, and therefore has a volumetric capacitance for electrochemical capacitors (ECs) up to 376 F cm(-3), which is the highest value so far reported for carbon materials in an aqueous electrolyte More promising, the carbon is conductive and moldable, and thus could be used directly as a well-shaped electrode sheet for the assembly of a supercapacitor device free of any additives, resulting in device-level high energy density ECs

Role of the prolyl isomerase Pin1 in protecting against age-dependent neurodegeneration

Abstract: The neuropathological hallmarks of Alzheimer's disease and other tauopathies include senile plaques and/or neurofibrillary tangles. Although mouse models have been created by overexpressing specific proteins including beta-amyloid precursor protein, presenilin and tau, no model has been generated by gene knockout. Phosphorylation of tau and other proteins on serine or threonine residues preceding proline seems to precede tangle formation and neurodegeneration in Alzheimer's disease. Notably, these phospho(Ser/Thr)-Pro motifs exist in two distinct conformations, whose conversion in some proteins is catalysed by the Pin1 prolyl isomerase. Pin1 activity can directly restore the conformation and function of phosphorylated tau or it can do so indirectly by promoting its dephosphorylation, which suggests that Pin1 is involved in neurodegeneration; however, genetic evidence is lacking. Here we show that Pin1 expression is inversely correlated with predicted neuronal vulnerability and actual neurofibrillary degeneration in Alzheimer's disease. Pin1 knockout in mice causes progressive age-dependent neuropathy characterized by motor and behavioural deficits, tau hyperphosphorylation, tau filament formation and neuronal degeneration. Thus, Pin1 is pivotal in protecting against age-dependent neurodegeneration, providing insight into the pathogenesis and treatment of Alzheimer's disease and other tauopathies.

ZnO as a novel photonic material for the UV region

Abstract: This paper will address the feasibility of ZnO as photonic material for the UV region. ZnO films are grown by plasma-assisted MBE. Detailed XRD studies suggest the growth of structurally different epilayers on Al2O3 (0001) and MgAl2O4 (111) substrates. PL shows dominant excitonic emission and very low deep level emission which is indicative of low density of defects or impurities. Stimulated emission based on the excitonic mechanism has been achieved up to 550 K. It is concluded that ZnO can be used for exciton-based photonic device applications owing to the high exciton binding energy. Optically pumped lasing has been demonstrated at room temperature.

Magnetic excitations in pure, lightly doped, and weakly metallic La2CuO4.

Abstract: We report a comprehensive neutron-scattering study of the evolution of the magnetic excitations in La[sub 2[minus][ital x]]Sr[sub [ital x]]CuO[sub 4] for 0[le][ital x][le]0.04. We first present accurate measurements of the magnetic correlation length and the sublattice magnetization of a carrier-free La[sub 2]CuO[sub 4] crystal and analyze these in the context of recent theoretical predictions. We then systematically investigate the influence of different dopants on the magnetism: Our measurements indicate that static vacancies in the La[sub 2]Cu[sub 1[minus][ital y]]Zn[sub [ital y]]O[sub 4] system affect the magnetic correlations in a similar manner as electrons in Pr[sub 2[minus][ital x]]Ce[sub [ital x]]CuO[sub 4]. The magnetic correlation length is much more rapidly suppressed as a function of [ital x] in La[sub 2[minus][ital x]]Sr[sub [ital x]]CuO[sub 4], and for [ital x][le]0.04 we find that it obeys the empirical relation [xi][sup [minus]1]([ital x],[ital T])=[xi][sup [minus]1]([ital x],0)+[xi][sup [minus]1](0,[ital T]), where [xi](0,[ital T]) is the measured correlation length of the carrier-free sample. We also report an extensive set of measurements of the dynamical magnetic response function of a crystal of composition La[sub 1.96]Sr[sub 0.04]CuO[sub 4] for excitation energies 0.75[le][omega][le]45 meV and temperatures 1.5[le][ital T][le]500 K.