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Hydrolysis of the phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) at the cell membrane induces the release of inositol 1,4,5-trisphosphate (IP3) into the cytoplasm and diffusion of diacylglycerol (DAG) through the membrane, respectively. Release of IP3 subsequently increases Ca2+ levels in the cytoplasm, which results in activation of protein kinase C α (PKCα) by Ca2+ and DAG, and finally the translocation of PKCα from the cytoplasm to the membrane. In this study, we developed a metabolic reaction–diffusion framework to simulate PKCα translocation via PIP2 hydrolysis in an endothelial cell. A three-dimensional cell model, divided into membrane and cytoplasm domains, was reconstructed from confocal microscopy images. The associated metabolic reactions were divided into their corresponding domain; PIP2 hydrolysis at the membrane domain resulted in DAG diffusion at the membrane domain and IP3 release into the cytoplasm domain. In the cytoplasm domain, Ca2+ was released from the endoplasmic reticulum, and IP3, Ca2+, and PKCα diffused through the cytoplasm. PKCα bound Ca2+ at, and diffused through, the cytoplasm, and was finally activated by binding with DAG at the membrane. Using our model, we analyzed IP3 and DAG dynamics, Ca2+ waves, and PKCα translocation in response to a microscopic stimulus. We found a qualitative agreement between our simulation results and our experimental results obtained by live-cell imaging. Interestingly, our results suggest that PKCα translocation is dominated by DAG dynamics. This three-dimensional reaction–diffusion mathematical framework could be used to investigate the link between PKCα activation in a cell and cell function.

The tetragonal ternary compound TbIr 2 Si 2 shows polymorphism; the ThCr 2 Si 2 -type structure as a low temperature phase (I-phase) and the CaBe 2 Ge 2 -type one as a high temperature phase (P-phase) exist. In order to compare with magnetism of the morphs, magnetic measurements were performed on the I- and P-phase single crystals. The magnetic behavior changes drastically depending on the structure. The TbIr 2 Si 2 (I) shows an antiferromagnetic ordering below T N =80 K, a strong uniaxial magnetic anisotropy with the easy [001] direction, and isotropic magnetic behavior in the basal plane. The [001] magnetization shows a clear two-step metamagnetic transition: an Ising-like behavior at low temperatures. On the other hand, the TbIr 2 Si 2 (P) has the comparatively low ordering temperature of T N1 =11.5 K and an additional transition temperature of T N2 =5 K, and exhibits an easy-plane magnetic anisotropy with the easy [100] direction. A strong magnetic anisotropy appears for high magnetic fields between the directions in the basal plane. Multi-step metamagnetic processes appear. In the both phases, the χ - T behavior suggests the existence of component-separated magnetic transitions. The ab -component of magnetic moments orders at the higher transition temperature T N1 for the P-phase compound, which is contrast to the I-phase behavior; the c -component orders firstly at T N in the I-phase. The crystalline electric field analysis was made, and the CEF effects explain the different of magnetic anisotropy between the both phases.

Magnetic measurements on pseudoternary compounds Ho1-xGdxRh2Si2, which substitute Gd having no quadrupole for Ho, were performed. They exhibit a successive component-separated magnetic transition; the c- and ab-components of magnetic moments independently order at different temperatures TN1 and TN2, respectively. The partial ordered state, a frustration appears for TN1 >T > TN2: for the phase II in the magnetic phase diagrams. In the ordered phase, step-like metamagnetic processes appear for TN2 > T; two-step ones appear along the [001] and [100] directions, and a one-step one appears along the [110] direction. The B-T magnetic phase diagrams were constructed. There are six, four and three ordered phases in the B001-T, B100-T and B110-T phase diagram, respectively. Two diagrams of the basal plane directions, B100-T and B110-T, resemble each other. Some interesting or peculiar phase boundaries appear. The Gd composition x dependence of transition temperatures is determined. The transition temperatures TN1 and TN2 increase with increasing x. The x-dependency of TN1 is well scaled by the de Gennes factor: (g-1)2J(J+1) whereas the transition of TN2 is not scaled. Some magnetic features declare that quadrupole interactions play an important role in this compound system.

Magnetic studies were performed on PrPd2Si2 single crystals which crystallize in the tetragonal ThCr2Si2-type structure. The temperature dependence of the magnetic susceptibility indicates that the compound orders antiferromagnetically at temperatures below T N = 3.2 K. The transition was confirmed by specific heat measurements. Magnetization measurements at fields up to 18 T show that the easy magnetization direction is the [100] direction in the basal plane. In the magnetization process, five or four metamagnetic transitions appear; the process is a five (four)-step metamagnetic one. The [110] magnetization process is a three-step one. A strong magnetic anisotropy between the [100] and [110] directions is observed within the basal plane for high magnetic fields. Along the hard magnetization direction of the c-axis, a metamagnetic transition appears. The B [100] − T phase diagram was constructed. A magnetic anisotropy between the [100] and [001] directions is also strong. These behaviors are discussed based on an analysis of crystalline field effects.

Measurements of the magnetization and the specific heat were performed on a PrRh2 single crystal. A strong magnetic anisotropy with the easy magnetization direction of the c-axis is observed. Four anomalies appear in the temperature dependence of magnetic susceptibility along the c-axis; a cusp at TN=52 K, a high peak at T3=38 K, a shoulder at T2=33 K and a small peak at T1=4 K are observed, indicating magnetic transitions. The specific heat also shows four anomalies at the temperatures where the magnetic anomalies appear, confirming the occurrence of successive magnetic transitions. A clear two-step metamagnetic process appears along the easy magnetization direction of the c-axis at low temperatures. The magnetization in the first step is almost constant and is corresponds to (1/5) Ms (Ms: saturation magnetization), indicating that this field-induced phase has a long period and a stable magnetic structure. A metamagnetic process is hypothesized on the basis of the magnetic structure. The B001 − T phase diagram is constructed.

The cavitation surge is a kind of instability phenomenon generated in a liquid rocket engine, and it is known that when the inlet pressure of the turbopump of the engine is decreased, the frequency of cavitation surge continuously varied. On the other hand, it was observed in a turbopump test conducted in JAXA that the frequency of cavitation surge discontinuously decreased when the inlet pressure was decreased. Aiming at explaining this curious phenomenon, we conducted the linear analysis using the frequency-domain method and found that this phenomenon was a kind of self-excited vibration coupling the cavitation characteristics with the acoustic resonance of the inlet pipeline. However, the linear analysis could not simulate the phenomenon that a frequency of standing wave changed to the other mode at a certain inlet pressure. Therefore, we conducted the nonlinear analysis using the one-dimensional time-domain method. As a result, it was found that when the inlet pressure was decreased, the damping effect became larger in the higher frequency oscillation because of nonlinear factors. Consequently, the oscillation of higher frequency was intensely weakened and the oscillation of lower one appeared instead.

Effects of pressure on the physical properties are very important for understanding highly correlated electron systems, in which pressure-induced attractive phenomena such as superconductivity and magnetically ordered non-Fermi liquid have been observed. Up to now, many scientists have developed a lot of high pressure apparatus for each purpose. In this paper, we present the very small “palm cubic-anvil high-pressure apparatus” for precise electric transport measurements under high pressure up to 8 GPa. The most outstanding characteristic of this pressure cell is its compactness. This cell enables us to measure absolute values of electrical resistivity, magneto-resistance and Hall coefficient at various temperatures. The details of our palm cubic high-pressure apparatus are introduced, and some neutron experimental results at room temperature are discussed.

Magnetic characteristics of a DyPd2Si2 single crystal with the ThCr2Si2-type structure have been studied from measurements of magnetic susceptibility (T) and magnetization M(B). It was found that DyPd2Si2 orders antiferromagnetically below TN = 9.2 K with the basal-plane [100] axis being the easy magnetization direction at high magnetic fields. Upon increasing magnetic field, the [100] magnetization curve exhibits at least six metamagnetic transitions at 0.2, 1.8, 3.0, 3.7, 4.2 and 6.1 T before reaching the saturation magnetization Ms = 10 B. Five metamagnetic transitions were detected on decreasing fields. For the [110] magnetization process, three metamagnetic transitions were evidenced. In contrast, the M(B) curve along the [001] axis, which is the hard magnetization direction, displays no metamagnetic transition; it shows a monotonous increase with a concave curvature up to 18 T. Finally, we constructed a comprehensive B100-T magnetic phase diagram consisting of six magnetic ordered phases.

The need for large-scale electronic structure calculations arises recently in the field of material physics and efficient and accurate algebraic methods for large simultaneous linear equations become greatly important. We investigate the generalized shifted conjugate orthogonal conjugate gradient method, the generalized Lanczos method and the generalized Arnoldi method. They are the solver methods of large simultaneous linear equations of one-electron Schr\"odinger equation and maps the whole Hilbert space to a small subspace called the Krylov subspace. These methods are applied to systems of fcc Au with the NRL tight-binding Hamiltonian (Phys. Rev. B {\bf 63}, 195101 (2001)). We compare results by these methods and the exact calculation and show them equally accurate. The system size dependence of the CPU time is also discussed. The generalized Lanczos method and the generalized Arnoldi method are the most suitable for the large-scale molecular dynamics simulations from the view point of CPU time and memory size., Comment: 13pages, 7figures

A GW approximation (GWA) method named $\text{U}+\text{GWA}$ is proposed, where we can start GWA with more localized wave functions obtained by the local spin-density approximation $(\text{LSDA})+\text{U}$ method. Then GWA and $\text{U}+\text{GWA}$ are applied to MnO, NiO, and ${\text{V}}_{2}{\text{O}}_{3}$ in antiferromagnetic phase. The band gaps and energy spectra show excellent agreement with the experimentally observed results and are discussed in detail. The calculated width of $d$ bands of ${\text{V}}_{2}{\text{O}}_{3}$ is much narrower than that of the observed one which may be a mixture of ${t}_{2g}^{2}$ multiplet and single-electron ${t}_{2g}$ level. GWA or $\text{U}+\text{GWA}$ does not work also in the paramagnetic phase of ${\text{V}}_{2}{\text{O}}_{3}$ and the reason for this is clarified. The method of the unique choice of on-site Coulomb interaction is discussed in detail. The criterion for whether we should adopt GWA or $\text{U}+\text{GWA}$ is discussed and is assessed with the help of the off-diagonal elements of the self-energy.

The pressure ($p$) -- temperature ($T$) phase diagram for microscopic magnetism in the multiferroic compound HoMn$_{2}$O$_{5}$ was established using neutron diffraction measurements under a hydrostatic pressure up to 1.25 GPa. At ambient pressure, incommensurate--commensurate--incommensurate magnetic phase transitions occur successively with decreasing temperature. Upon applying pressure, the incommensurate phase at the lowest temperature almost decreases and the commensurate phase appears. The $p$ -- $T$ phase diagram established shows excellent agreement with the recently reported $p$ -- $T$ dielectric phase diagram, where ferroelectricity is induced by applying pressure. We also found that the $p$ -- $T$ magnetic phase diagram is quite similar to the previously obtained magnetic field-temperature phase diagram., Comment: 5 pages, 5 figures, to be published in J. Phys. Soc. Jpn

SmCoIn 5 crystallizes in the tetragonal HoCoGa 5 type structure. This type of crystal structure have attracted much attention because new heavy-fermion superconductivity with very high superconducting transition temperature T c = 18.5 K was discovered in PuCoGa 5 . It is expected that Sm has a similar ground state to Pu compounds. Thus we have measured the electrical resistivity on a single crystal of SmCoIn 5 using a cubic anvil pressure cell at temperature 2–300 K under high pressure from 2 to 8 GPa. The value of T N that was 11.9 K at ambient pressure in SmCoIn 5 increased to 13.2 K at P = 2 GPa. Above 2 GPa, It decreased monotonously with increasing pressure and was 12.6 K at 8 GPa. It may be thought that the 4 f electrons in SmCoIn 5 are more localized than 5 f electrons in PuCoGa 5 .

We report the electrical resistivity and specific heat of the intermediate-valence intermetallic compound YbAl 2 . A single-crystalline YbAl 2 was synthesized by the Li-flux-growth technique. Electrical resistivity measurements were performed under high pressures up to 2.3 GPa. The value of the electrical resistivity increases with increasing pressure. This behavior is attributed to the gradual increase of the Yb valence in YbAl 2 .

A small hybrid CuBe/NiCrAl piston–cylinder-type high-pressure (HP) clamp cell was designed for low-temperature (LT) neutron diffraction (ND) measurements, and its characteristics was evaluated through various parameters which include cooling performance, transmission efficiency for neutrons. The cell successfully produces pressure up to 2.5 GPa at room temperature (RT).

Thermal variations of magnetization under various magnetic fields and magnetization processes at various temperatures have been studied on a HoRh2Si2 single crystal compound. Three anomalies at TN1=29.1 K, Tt=27.3 K and TN2=12.0 K exist at low field in the thermal variation. The thermal dependence of M/B and the magnetization change drastically with magnetic field. Step-like metamagnetic processes appear along the all directions below TN2; two-step ones appear along the [001] and [100] directions, and a one-step one appears along the [110] direction. For TN2

High field magnetization measurement were performed up to 45 T using a long pulse magnet on a GdPd2Si2 single crystal compound having the tetragonal ThCr2Si2-type crystal structure and an antiferromagnetic ordering of TN=16.7 K. The magnetization processes are almost typical antiferromagnetic ones with a weak magnetic anisotropy though small anomalies exist in the processes. The magnetization saturates 7 μB/f.u. above Bs=32 T. The B001-T and B100-T magnetic phase diagrams were constructed. There are three phases, the phase I, II and III, under non-magnetic field in the ordered state for both diagrams. The field-induced phase, phase IV, appears below the paramagnetic phase by the [100] magnetic field, B100, which is accompany with a re-entrant behaviour. The B100 makes the phase II be stable and the phase I and III be instable. These strange behaviours indicate the direction of the magnetic moment changes in each phase.

Magnetic susceptibility and specific heat measurements have been carried out on a HoRh2Si2 single crystal compound. Specific heat shows two λ-like anomalies at TN1=29.1 K and TN2=12.0 K, and an additional sharp anomaly indicating the first order transition at Tt=27.3 K. The temperature dependence of susceptibility along the [001] direction shows a clear cusp at TN1 but a tiny kink at TN2 and Tt. In contrast, those in the ab-plane show a clear cusp at TN2. HoRh2Si2 shows a successive component-separated magnetic transition coming from a new type frustration not geometrical one.

Magnetic and specific heat measurements have been performed on a GdPd2Si2 single crystal compound having the tetragonal ThCr2Si2-type crystal structure. Specific heart shows two λ-type anomalies at TN=16.7 K, T1=12.3 K and a small hump with hysteresis at T2=6.8 K; there are three phases below TN. The magnetic entropy of Rln6 is released below TN. The temperature dependence of magnetic susceptibility shows a very peculiar behaviour. With decreasing temperature, the magnetic susceptibility along the [001] direction increases through a small kink at TN down to T1 where a clear cusp is seen, decreases rapidly below TN, then shows an upturn and a clear kink at T2 followed by a gradual increase. This behaviour examines at various magnetic field along [001] and [100]. The B001-T and B100-T magnetic phase diagrams have been constructed. The field-induced phase appears near by the 100] magnetic field, B100.

It was found the growth method of single crystals of ternary lanthanide transition metal phosphide RRu2P2 (R=La, Ce,Pr and Eu) with enough large volume to measure the macroscopic physical properties, such as magnetization, electrical resistivity and specific heat. As a result, we succeeded in the measurements of electrical resistivity with a sufficiently good accuracy and reveal an experimental evidence of the superconducting transition in LaRu2P2 for the first time. On the basis of the results of electrical resistivity measurements we discuss that how P-P bonding state does affect on the electrical transport properties of RRu2P2 compounds.

We have developed a set-up with modified "seesaw heating method" for the thermopower measurement under pressures P up to 3 GPa at the temperature range between 2 K and 300 K. By using this set-up, the thermopower and electrical resistivity of the single crystalline YbMn2Ge2 under high pressure were measured with enough accuracy. S(T) curve shows the characteristic feature at the magnetic transition in all pressure range, while no evidence of the magnetic phase transition is observed in ρ(T) at P > 1.25 GPa. The measurement results indicate that the simultaneous measurement of the thermopower and electrical resistivity is a useful tool to study the pressure-induced phase transitions.

The measurements of electrical resistivity ρ and thermopower S of the single-crystalline EuCo2P2 have been performed at temperatures from 2 K to 300 K under hydrostatic pressures up to 3 GPa. The temperature dependence of ρ and S show drastic changes at the critical pressure Pc, indicating a large modification of electronic structure around the Fermi level due to a pressure-induced structural and magnetic phase transition. The magnetic phase transition temperature increases linearly with increasing pressure, and shows a sudden increase at the critical pressure Pc, which correspond to the change of magnetic state from the localized Eu(4f) sub-lattice magnetism into the itinerant Co(3d) sub-lattice magnetism.

The B-T magnetic phase diagrams for TbCu2Si2 single crystal, having the tetragonal ThCr2Si2-type crystal structure, have been constructed from magnetic measurements. The compound orders antiferromagneticaly below TN=11.9 K and shows another magnetic transition at Tt=9.1 K. In the easy magnetization direction of [110], a six-step metamagnetic process appears at low temperatures. Above Tt, it becomes a two-step metamagnetic one. There are seven ordered magnetic phases below the paramagnetic region in the B110-T magnetic phase diagram. In the [100] magnetization process, three metamagnetic transitions appear at low temperatures. The magnetization process becomes a one-step one above Tt. The B100-T phase diagram, composed of four phases, is very peculiar; a quad-critical point may appear. The magnetic structure for each phase has been discussed.

We have studied the electrical resistivity of YbCo2Zn20 under magnetic field up to 18 T. With applying magnetic field, the contribution of the Kondo interaction to the electrical resistivity is suppressed and the Fermi liquid regime is extended to higher temperature range. Both the T2 coefficient of the electrical resistivity A and the residual resistivity ρ0 strongly decrease in magnetic field. From the magnetic variation of the resistivity, it has been found that YbCo2Zn20 is classified as a heavy fermion system with small Kondo temperature of ~ 1.0K.

The thermopower S and electrical resistivity ρ of YbMn2 Ge2 were measured under pressures up to 2 GPa in the temperature range from 1.5 to 300 K. The magnetic transition temperature increases with increasing pressure, having maximum at Pc ≈ 1.3 GPa, and decreases with increasing pressure above P > 1.3 GPa. The temperature dependences of S and ρ change their features at critical pressure Pc ≈ 1.3 GPa, where reported that the mean Yb valence value changes from +2.4 to +2.8 at room-temperature. The pressure dependences of S and ρ at 4.2 and 300 K show the abrupt changes at the critical pressure, which indicate the changes of the electronic state near the Fermi level and the magnetic structure of Mn 3d electron.

An early-stage version of simulation package ' ELSES' (Extra-Large-Scale Electronic-Structure calculation) is developed for electronic structure and dynamics of large systems, particularly, nm-scale or 10nm-scale systems (www.elses.jp). Input and output files are written in the Extensible Markup Language (XML) style for general users. Related pre-/post-simulation tools are also available. Practical work flow and example are described. A test calculation of GaAs bulk system is shown to demonstrate that the present code can handle systems with more than one atom species. Several future aspects are also discussed., Comment: 7 Pages, 4 figures. A PDF file in better graphics is available at http://fujimac.t.u-tokyo.ac.jp/lses/index_e.html

We report the results of investigation of the thermopower (Seebeck effect) of a ThCr2Si2-structured heavy fermion single-crystalline YbPd2Si2 compound (itterbium-palladium-silicon, 1-2-2) under ultra high pressure P up to 22 GPa. At ambient conditions the thermopower S was found to be negative. Under pressurization S inverted its sign and exhibited a bend near 6 GPa. The compressibility of YbPd2Si2 also showed a bend near 6 GPa corroborating a supposition about phase transformation.

We review the methods that we recently developed for making large-scale electronic structure calculations, both using one-electron theory and using many-electron theory. The methods are based on the density matrix representation, together with the Wannier state representation and the Krylov subspace method, using one-electron theory of systems on a scale of a few tens of nanometers. The hybrid method of quantum mechanical molecular dynamical simulation is explained. The Krylov subspace method, the CG (conjugate gradient) method and the shifted COCG (conjugate orthogonal conjugate gradient) method can be applied in the investigation of the ground state and the excitation spectra using many-electron theory. The mathematical foundation of the Krylov subspace method for large-scale matrix computation is focused on, and the key techniques of the shifted COCG method, i.e. using the collinear residual and 'seed-switching', are explained. A wide variety of applications of the extended novel algorithm are also explained. These include studies of fracture formation and propagation, liquid carbon, and formation processes of gold nanowires, together with the application to the extended Hubbard model.

We have measured the electrical resistivity of a single crystal of YbCo2Zn20 at pressures up to 2.37 GPa and at temperatures from 50 mK to 300 K. Above a critical pressure P. (similar to I GPa), we have found a resistivity anomaly at T-M (similar to 0.15 K at 1 GPa) that increases with the pressure. At the ambient pressure, the system shows a nonmagnetic ground state described by the Fermi-liquid model. The T-2 coefficient of the electrical resistivity A strongly increases with the pressure upon approaching Pc. However, in the vicinity of P,, the temperature dependence of the resistivity deviates from the Fermi-liquid description. These observations suggest that the application of hydrostatic pressure induces a magnetically ordered state for P >= P-c and T

Fermi surfaces of several quasicrystalline approximants are calculated by means of ab-initio methods which enable direct comparison with dHvA experiments. A criterion for anomalous metallic transport is proposed and power-law temperature dependence of electronic conductivity is deduced from scaling analysis of the Kubo formula., Comment: 8 pages, 7 figures. to appear in Phys. Rev. B