Tohoku University

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

Magnetic, transport, and optical properties of monolayer copper oxides

Abstract: The authors review the results of a wide variety of experiments on materials such as ${\mathrm{La}}_{2}{\mathrm{CuO}}_{4}$ and ${\mathrm{Nd}}_{2}{\mathrm{CuO}}_{4}$ that contain weakly coupled ${\mathrm{CuO}}_{2}$ layers. These materials are antiferromagnetic insulators with very large Heisenberg exchange energies, which become high-temperature superconductors when charge carriers are added to the ${\mathrm{CuO}}_{2}$ layers. The growth of large single crystals has made it possible to carry out neutron scattering, as well as anisotropic optical, transport, and magnetization measurements. The properties of the undoped ${\mathrm{CuO}}_{2}$ layer are reviewed, and the evolution of magnetic, optical, and transport properties with the addition of charge carriers is discussed. The emphasis is on the pure and lightly doped materials, although the magnetism in the superconductors is discussed.

A functional MOS transistor featuring gate-level weighted sum and threshold operations

Abstract: A functional MOS transistor is proposed which works more intelligently than a mere switching device. The functional transistor calculates the weighted sum of all input signals at the gate level, and controls the 'on' and 'off' of the transistor based on the result of such a weighted sum operation. Since the function is quite analogous to that of biological neurons, the device is named a neuron MOSFET, or neuMOS (vMOS). The device is composed of a floating gate and multiples of input gates that capacitively interact with the floating gate. As the gate-level sum operation is performed in a voltage mode utilizing the capacitive coupling effect, essentially no power dissipation occurs in the calculation, making the device ideal for ULSI implementation. The basic characteristics of neuron MOSFETs as well as of simple circuit blocks are analyzed based on a simple transistor model and experiments. Making use of its very powerful function, a number of interesting circuit applications are explored. A soft hardware logic circuit implemented by neuMOS transistors is also proposed. >

Reactive cysteine persulfides and S-polythiolation regulate oxidative stress and redox signaling.

Abstract: Using methodology developed herein, it is found that reactive persulfides and polysulfides are formed endogenously from both small molecule species and proteins in high amounts in mammalian cells and tissues. These reactive sulfur species were biosynthesized by two major sulfurtransferases: cystathionine β-synthase and cystathionine γ-lyase. Quantitation of these species indicates that high concentrations of glutathione persulfide (perhydropersulfide >100 μM) and other cysteine persulfide and polysulfide derivatives in peptides/proteins were endogenously produced and maintained in the plasma, cells, and tissues of mammals (rodent and human). It is expected that persulfides are especially nucleophilic and reducing. This view was found to be the case, because they quickly react with H2O2 and a recently described biologically generated electrophile 8-nitroguanosine 3′,5′-cyclic monophosphate. These results indicate that persulfides are potentially important signaling/effector species, and because H2S can be generated from persulfide degradation, much of the reported biological activity associated with H2S may actually be that of persulfides. That is, H2S may act primarily as a marker for the biologically active of persulfide species.