Tatsuhiko N. Ikeda 교수

Human type beta 2 transforming growth factor (hTGF-beta 2) was purified from tamoxifen-supplemented, serum-free medium conditioned by the human prostatic adenocarcinoma cell line PC-3. The purification of hTGF-beta 2 was monitored in a growth inhibition assay and was achieved by batch purification on methylsilyl-controlled pore glass, followed by gel permeation chromatography and reversed-phase high-performance liquid chromatography. The overall recovery of hTGF-beta 2 was 75% of the initial act

By calculating correlation functions for the Lieb-Liniger model based on the algebraic Bethe ansatz method, we conduct a finite-size scaling analysis of the eigenstate thermalization hypothesis (ETH), which is considered to be a possible mechanism of thermalization in isolated quantum systems. We find that the ETH in a weak sense holds in the thermodynamic limit even for an integrable system, although it does not hold in the strong sense. Based on the result of the finite-size scaling analysis,

A rapid and easy determination method of green tea’s quality was developed by using Fourier transform near-infrared (FT-NIR) reflectance spectroscopy and metabolomics techniques. The method is applied to an online measurement and an online prediction of green tea’s quality. FT-NIR was employed to measure green tea metabolitesʼ alteration affected by green tea varieties and manufacturing processes. A set of ranked green tea samples from a Japanese commercial tea contest was analyzed to create a r

Laser technology has developed and accelerated photo-induced nonequilibrium physics, from both the scientific and engineering viewpoints. Floquet engineering, i.e., controlling material properties and functionalities by time-periodic drives, is at the forefront of quantum physics of light-matter interaction. However, it is limited to ideal dissipationless systems. Extending Floquet engineering to various materials requires understanding of the quantum states emerging in a balance of the periodic

We derive an upper bound on the difference between the long-time average and the microcanonical ensemble average of observables in isolated quantum systems. We propose, numerically verify, and analytically support a new hypothesis, the eigenstate randomization hypothesis (ERH), which implies that in the energy eigenbasis the diagonal elements of observables fluctuate randomly. We show that ERH includes the eigenstate thermalization hypothesis (ETH) and makes the aforementioned bound vanishingly

Sunitinib is an oral multitargeted receptor tyrosine kinase inhibitor with antiangiogenic and antitumor activity that mainly targets vascular endothelial growth factor receptors, and recently, it has been shown to be an active agent for the treatment of malignant pheochromocytomas. Previously, we demonstrated that sunitinib directly inhibited mTORC1 signaling in rat pheochromocytoma PC12 cells. Although autophagy is a highly regulated cellular process, its relevance to cancer seems to be complic

High-harmonic generation (HHG), a typical nonlinear optical effect, has been actively studied in electron systems such as semiconductors and superconductors. As a natural extension, we theoretically study HHG from electric polarization, spin current, and magnetization in magnetic insulators under terahertz or gigahertz electromagnetic waves. We use simple one-dimensional spin-chain models with or without multiferroic coupling between spins and the electric polarization, and study the dynamics of

Histidine and its derivatives increased rabbit muscle fructose 1,6-bisphosphatase activity at neutral pH with positive cooperativity. In the presence of histidine and carnosine the optimum pH shifted from pH 8.0 to 7.4. The cooperative response of the enzyme to AMP and fructose 1,6-bisphosphate was observed in the presence of the histidine derivatives. Of a number of divalent cations tested, only Zn2+ was found to be an effective inhibitor of enzyme activity at low concentrations. The kinetic da

By using the Floquet eigenstates, we derive a formula to calculate the high-order harmonic components of the electric current (HHC) in the setup where a monochromatic laser field is turned on at some time. On the basis of this formulation, we study the HHC spectrum of electrons on a one-dimensional chain with a staggered potential to study the effect of multiple sites in the unit cell such as the systems with charge density wave order. With the help of the solution for the Floquet eigenstates, w

We study heating dynamics in isolated quantum many-body systems driven periodically at high frequency and large amplitude. Combining the high-frequency expansion for the Floquet Hamiltonian with Fermi's golden rule (FGR), we develop a master equation termed the Floquet FGR. Unlike the conventional one, the Floquet FGR correctly describes heating dynamics, including the prethermalization regime, even for strong drives, under which the Floquet Hamiltonian is significantly dressed, and nontrivial F

Of a number of divalent cations investigated, Zn2+ strongly inhibited lactate production from glucose 6-phosphate in rat muscle cytosol fraction. The I50 value for lactate production influenced by Zn2+ was 10 microM and was increased to 200 microM and 18 microM by the addition of 10mM histidine and 10mM carnosine, respectively. The inhibitory effect of 50 microM Zn2+ on lactate production was completely reversed by the addition of 1.2mM histidine and the apparent Km was found to be 0.34mM. The i

Nonequilibrium steady states (NESSs) in periodically driven dissipative quantum systems are vital in Floquet engineering. We develop a general theory for high-frequency drives with Lindblad-type dissipation to characterize and analyze NESSs. This theory is based on the high-frequency (HF) expansion with linear algebraic numerics and without numerically solving the time evolution. Using this theory, we show that NESSs can deviate from the Floquet-Gibbs state depending on the dissipation type. We

We develop the Landau-Zener transfer matrix theory for the instantaneous Floquet states (IFSs) for quantum systems driven by a strong pulse laser. Applying this theory to the pulse excitation probability in two-level quantum systems, we show unexpectedly good quantitative agreement for few-cycle pulses. This approach enables us to qualitatively understand the probability's peculiar behaviors as quantum path interference between IFSs. We also study the pulse-width dependence, finding that this Fl