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S Inagaki

Publications and source records attributed to S Inagaki.

At least 37 records · Page 2Linked to original sources
PubMed2001

Creep motion in a granular pile exhibiting steady surface flow.

We investigate experimentally granular piles exhibiting steady surface flow. Below the surface flow, it has been believed that a "frozen" bulk region exists, but our results show no such frozen bulk. We report here that even the particles in layers deep in the bulk exhibit very slow flow and that such motion can be detected at an arbitrary depth. The mean velocity of the creep motion decays exponentially with depth, and the characteristic decay length is approximately equal to the particle size and is independent of the flow rate. It is expected that the creep motion we have seen is observable in all sheared granular systems.

Journal Article↗
PubMed2001

Orbital phase control of the preferential branching of chain molecules.

The orbital phase theory was applied to the stabilities of the branched isomers (1) of E(4)H(10) (E = C, Si, Ge, Sn) relative to the normal ones (2). The orbital phase prediction was confirmed by ab initio molecular orbital (MO) and density functional theory (DFT) calculations as well as by some experimental results. Further applications to the relative stabilities of other alkane and alkene isomers lead to the preference of the branched to the normal isomers, the neopentane-type to isobutane-type branching, the terminal to inner methyl branching, and the methyl to ethyl inner substitution in the longer alkanes, as well as the preference of isobutene to 2-butene moieties. The preferential stabilization of the branched isomers was shown to be general and controlled by the orbital phase.

Journal Article↗
PubMed2001

Mesoporous titanium phosphate molecular sieves with ion-exchange capacity.

Novel open framework molecular sieves, titanium(IV) phosphates named, i.e., TCM-7 and -8 (Toyota Composite Materials, numbers 7 and 8), with new mesoporous cationic framework topologies obtained by using both cationic and anionic surfactants are reported. The (31)P MAS NMR, UV-visible absorption, and XANES data suggest the tetrahedral state of P and Ti, and stabilization of the tetrahedral state of Ti in TCM-7/8 is due to the incorporation of phosphorus (at Ti/P = 1:1) vis-à-vis the most stable octahedral state of Ti in the pure mesoporous TiO(2). Mesoporous TCM-7 and -8 show anion exchange capacity due to the framework phosphonium cation and cation exchange capacity due to defective P-OH groups. The high catalytic activity in the liquid-phase partial oxidation of cyclohexene with a dilute H(2)O(2) oxidant supports the tetrahedral coordination of Ti in these materials.

Journal Article↗
PubMed2001

Semaphorin 4C, a transmembrane semaphorin, [corrected] associates with a neurite-outgrowth-related protein, SFAP75.

Semaphorin 4C (S4C, previously called M-SemaF) was recently identified as a brain rich transmembrane member of semaphorin family of the vertebrate. In the cytoplasmic domain of S4C there is a proline-rich region suggesting that the cytoplasmic domain may play an important role in Sema4C function. In this study, we have identified the cytoplasmic domain (cd) of M-SemaF(S4C)-associating protein with a Mr of 75 kDa, named SFAP75, from mouse brain. SFAP75 turned out to be the same as the recently reported neurite-outgrowth-related protein named Norbin. Deletion mutants analyses of S4C and SFAP75 revealed that the membrane-proximal region of S4Ccd binds to the intermediate region of SFAP75. Western blot and immunohistochemical analyses with anti-Sema4C and anti-SFAP75 antibodies indicated that S4C and SFAP75 were specially enriched in the brain with a similar distribution pattern to each other. These results suggest that S4C interacts with SFAP75 and plays a role in neural function in brain.

Animals↗
PubMed2001

Polyacrylamides as hydrophilic selectors in non-aqueous capillary electrophoresis.

Polyacrylamides (PAAms) were investigated as hydrophilic selectors in non-aqueous capillary electrophoresis (CE). Separation of 10 substituted benzoates and unsubstituted benzoate as model samples was greatly improved by the addition of PAAms in acetonitrile-CE. The migration behavior indicates that the carbonyl moiety of PAAms works as a good hydrogen-accepting site toward hydrogen-donating analytes such as 4-hydroxybenzoate anion (4OH-BA) in acetonitrile. PAAms also serve as electron-accepting agents with its amide proton interacting with the dissociated carboxyl groups of the benzoates. The ion-dipole interaction is useful to control the migration behavior of benzoates without hydrogen-donating substituents. The overall mode of the interaction is similar to that of polyethylene glycol (PEG) 20000 reported previously, but the complex formation constant of poly(N-tert.-butyl)acrylamide (PBAAm) with 40H-BA estimated here was 130-fold larger than that of PEG 20000. This would be ascribed to the strong basicity of the carbonyl oxygen atoms of PBAAm as compared with the ether oxygen atoms of PEG. Furthermore, a copolymer of (N-tert.-butyl)acrylamide-acrylamide [70:30 (in feed)] exhibited a complex formation constant of about fourfold larger toward 4OH-BA than PBAAm, most probably due to decrease in steric hindrance from the tert.-butyl groups. Adrenaline and its six precursors have been separated successfully using the PAAms.

Acetonitriles↗
PubMed2001

Separation of N2-ethyl-2'-deoxyguanosine-5'-monophosphate and four native deoxyribonucleoside monophosphates using capillary zone electrophoresis with polyethylene glycol as buffer additive.

We investigated the separation of five deoxyribonucleoside monophosphates: 2'-deoxyguanosine-5'-monophosphate (dGMP), 2'-deoxyadenosine-5'-monophosphate (dAMP), 2'-deoxycytosine-5'-monophosphate (dCMP), 2'-deoxythymidine-5'-monophosphate (dTMP) and a dGMP adduct possessing N2-ethyl-guanine, which has been noted in relation to mutagenesis of alcohol, using capillary zone electrophoresis (CZE). The concentration of polyethylene glycol (PEG) as a modifier and the pH of the running solutions can efficiently control the observed separation. Interaction of PEG with analytes was quantitatively evaluated. PEG worked effectively as a hydrophobic selector in these separations. The values of pKa of the acidic-NH-groups in the base moieties of dGMP, dTMP, and the dGMP adduct are close to that of boric acid used as buffer of the running solutions. The control of their charge was facilitated, enabling improved separations. A more sufficient and fast separation was achieved by both optimization of pH of the running solutions and PEG concentration compared with that obtained by pH control alone. On-line concentration using a stacking method followed by the PEG-assisted CZE was briefly studied.

Borates↗
PubMed2001

Analysis of DNA adducts bases by capillary electrophoresis with amperometric detection.

We have developed a method for the detection of DNA adducts by combining capillary electrophoresis (CE) with the specificity of amperometric detection. Guanine is the most easily damaged base of the four normal DNA bases and many adducts of guanine have been found in DNA. These guanine adducts are often electrochemically active, while the normal bases with the exception of guanine are not. Therefore, CE with amperometric detection will be a promising method to study DNA damage. The four normal deoxynucleosides and two damaged deoxnucleosides N2-ethyldeoxyguanosine (N2-ethyl-dG) and 8-hydroxydeoxyguanosine (8-OH-dG), were completely separated by micellar electrokinetic chromatography (MEKC). Deoxyguanosine and the two damaged deoxynucleosides were identified using amperometric detection. The sensitivity of our system was comparable to that of UV detection. Analysis of DNA hydrolysis products was also performed briefly using this method.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Suppressive role of endogenous regucalcin in the enhancement of protein kinase activity with proliferation of cloned rat hepatoma cells (H4-II-E).

The role of endogenous regucalcin, which is a regulatory protein in calcium signaling, in the regulation of protein kinase activity in the proliferation of the cloned rat hepatoma cells (H4-II-E) was investigated. Hepatoma cells were cultured for 6-72 h in the presence of fetal bovine serum (FBS; 1 or 10%). The number of cells and protein kinase activity in the 5500 g supernatant of cell homogenate was significantly increased 24 and 48 h after the culture with FBS (1 or 10%); the culture with 10% FBS was potent effect as compared with that of 1% FBS. FBS (10%)-increased protein kinase activity preceded a significant elevation of cell number of 6 h after culture. Serum stimulation-induced increase in protein kinase activity was significantly decreased in the presence of trifluoperazine (50 microM), staurosporine (10(-6) M) or genistein (10(-5) M) in the enzyme reaction mixture. The presence of anti-regucalcin monoclonal antibody (40 or 80 ng/ml) in the reaction mixture caused a significant increase in protein kinase activity in the cells cultured with FBS (1 or 10%). This increase was completely blocked by addition of regucalcin (10(-6) M), which can reveal an inhibitory effect on protein kinase activity. Moreover, the effect of antibody in increasing protein kinase activity was significantly inhibited in the presence of trifluoperazine, staurosporine, or genistein, indicating that endogenous regucalcin has an inhibitory effect on Ca(2+)/calmodulin-dependent protein kinase, protein kinase C, and protein tyrosine kinase. The present study suggests that endogenous regucalcin plays a suppressive role in the enhancement of various protein kinase activities associated with a proliferation of the cloned rat hepatoma cells (H4-II-E).

Animals↗
PubMed2001

Regulatory role of endogenous regucalcin in the enhancement of nuclear deoxyribonuleic acid synthesis with proliferation of cloned rat hepatoma cells (H4-II-E).

The role of endogenous regucalcin in the regulation of deoxyribonuleic acid (DNA) synthesis in the nuclei of the cloned rat hepatoma cells (H4-II-E) with proliferative cells was investigated. Cells were cultured for 6-96 h in a alpha-minimum essential medium (alpha-MEM) containing fetal bovine serum (FBS; 1 or 10%). Cell number was significantly increased between 24 and 96 h after culture with 10% FBS; cell proliferation was markedly stimulated by culture with 10% FBS as compared with that of 1% FBS. In vitro DNA synthesis activity in the nuclei of cells was significantly elevated 6 h after culture with 10% FBS and its elevation was remarkable at 12 and 24 h after the culture. Nuclear DNA synthesis activity was significantly reduced in the presence of various protein kinase inhibitors (PD98059, staurosprine, or trifluoperazine) in the reaction mixture containing the nuclei of cells cultured for 12 and 24 h with FBS (1 and 10%). The addition of regucalcin (10(-7) and 10(-6)M) in the reaction mixture caused a significant inhibition of nuclear DNA synthesis activity. The presence of anti-regucalcin monoclonal antibody (25-100 ng/ml) in the reaction mixture containing the nuclei of cells cultured for 24 h with 10% FBS resulted in a significant increase in nuclear DNA synthesis activity. This increase was completely blocked by the addition of regucalcin (10(-6) M). The effect of anti-regucalcin antibody (100 ng/ml) in increasing nuclear DNA synthesis activity was significantly inhibited in the presence of various protein kinase inhibitors. DNA synthesis activity was significantly enhanced in the presence of anti-regucalcin antibody (100 ng/ml) in the reaction mixture containing the nuclei of cells cultured for 24 h with 10% FBS in the presence of Bay K 8644 (2.5 x 10(-6) M). Culture with Bay K 8644 did not cause a significant increase in DNA synthesis activity in the absence of anti-regucalcin antibody. The present study demonstrates that endogenous regucalcin plays a suppressive role in the enhancement of nuclear DNA synthesis with proliferative cells.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2001

Suppression of cell proliferation and deoxyribonucleic acid synthesis in the cloned rat hepatoma H4-II-E cells overexpressing regucalcin.

The role of endogenous regucalcin (RC) in the regulation of cell proliferation was investigated in the cloned rat hepatoma H4-II-E cells overexpressing RC stably. H4-II-E cells were transfected with RC/pCXN2 vector and the multiple neomycin-resistant clones which overexpress stably RC were selected. The RC content of RC/pCXN2-transfected cells used in this study was 19.7-fold as compared with that of the parental wild type H4-II-E cells. Wild type H4-II-E cells, pCXN2 vector-transfected cells (mock type), and RC/pCXN2-transfected cells (transfectants) were cultured for 24, 48, and 72 h in the presence of fetal bovine serum (10% FBS). Cell numbers of wild and mock type were significantly increased with the time course of culture. Cell numbers of transfectants was significantly suppressed as compared with that of wild and mock type. Deoxyribonucleic acid (DNA) synthesis activity in the nuclear fraction of H4-II-E cells was significantly suppressed in transfectants with culture for 12-48 h. The presence of anti-RC monoclonal antibody (10-50 ng/ml) in the reaction mixture caused a significant increase in DNA synthesis activity in the nuclei of wild type and transfectants; this increase was remarkable in transfectants. The effect of anti-RC monoclonal antibody (50 ng/ml) in increasing DNA synthesis activity in transfectants was completely prevented by the addition of regucalcin (1 microM). This study demonstrates that cell proliferation is suppressed in the cloned rat hepatoma H4-II-E overexpressing RC stably.

Animals↗
PubMed2001

Inhibitory action of Oren-gedoku-to extract on enzymatic lipid peroxidation in rat liver microsomes.

We examined the inhibitory action of the extract of Oren-gedoku-to, a traditional herbal medicine known to act as an antioxidant, on enzymatic lipid peroxidation in rat liver microsomes. Simultaneous addition of a spray-dried preparation of Oren-gedoku-to extract (Tsumura TJ-15) inhibited enzymatic lipid peroxidation induced by reduced beta-nicotinamide adenine dinucleotide phosphate (NADPH) and ADP/Fe3+ complex in liver microsomes in a dose-dependent manner. When the inhibition by TJ-15 of enzymatic lipid peroxidation in liver microsomes was kinetically analyzed, this medicine showed a competitive inhibition against NADPH or ADP/Fe3+ complex. TJ-15 inhibited the NADPH-driven enzymatic reduction of ADP/Fe3+ complex or cytochrome c in liver microsomes competitively. TJ-15 enhanced NADPH consumption by liver microsomes with ADP/Fe3+ complex. Treatment with TJ-15 after the onset of enzymatic lipid peroxidation in liver microsomes inhibited the progression of lipid peroxidation in a dose-dependent manner. The present results indicate that Oren-gedoku-to extract inhibits enzymatic lipid peroxidation in rat liver microsomes in the initiation and propagation steps in a dose-dependent manner. These results also suggest that Oren-gedoku-to extract inhibits enzymatic lipid peroxidation in rat liver microsomes not only through its antioxidant action but also through reduction of the supply of electrons derived from NADPH to ADP/Fe3+ complex in liver microsomes both in a competitive manner and through stimulation of NADPH oxidation.

Adenosine Diphosphate↗
PubMed2001

A handy detection cell for end-column electrochemical detection in capillary electrophoresis.

A handy and simple detection cell was constructed using a mixing joint for end-column electrochemical detection in capillary electrophoresis (CE). The cell allows for positioning of the working electrode at the end of the separation capillary without the aid of micropositioners. The design facilitates the exchange of electrodes and capillaries without the need to refabricate the entire capillary-electrode setup. The cell can be assembled in a short period of time. Alignment with the joint screw proved to be reproducible for working electrodes of copper and gold. The advantages of reduced time and low cost make the device very attractive for the routine analysis of electroactive species, such as carbohydrates and their derivatives, purine bases and nucleosides, amino acids, and catecholamines etc. by CE with electrochemical detection.

Journal Article↗
PubMed2000

Sema4c, a transmembrane semaphorin, interacts with a post-synaptic density protein, PSD-95.

Semaphorins are known to act as chemorepulsive molecules that guide axons during neural development. Sema4C, a group 4 semaphorin, is a transmembrane semaphorin of unknown function. The cytoplasmic domain of Sema4C contains a proline-rich region that may interact with some signaling proteins. In this study, we demonstrate that Sema4C is enriched in the adult mouse brain and associated with PSD-95 isoforms containing PDZ (PSD-95/DLG/ZO-1) domains, such as PSD-95/SAP90, PSD-93/chapsin110, and SAP97/DLG-1, which are concentrated in the post-synaptic density of the brain. In the neocortex, S4C is enriched in the synaptic vesicle fraction and Triton X-100 insoluble post-synaptic density fraction. Immunostaining for Sema4C overlaps that for PSD-95 in superficial layers I-IV of the neocortex. In neocortical culture, S4C is colocalized with PSD-95 in neurons, with a dot-like pattern along the neurites. Sema4C thus may function in the cortical neurons as a bi-directional transmembrane ligand through interacting with PSD-95.

Animals↗
PubMed2000

Ion heating and high-energy-particle production by ion-cyclotron heating in the large helical device

Ion-cyclotron heating was applied to the Large Helical Device. When the proton-cyclotron resonance was near the saddle point of the magnetic field-strength plane, strong ion-cyclotron damping occurred. Under these conditions efficient plasma heating was achieved for more than one minute. A high-energy ion tail was observed, and the effective tail temperature was determined by a balance between the wave acceleration and the electron-drag relaxation. There was no apparent sign of particle orbit loss effect in the investigated density range of 0.8-1.3x10(19) m(-3).

Journal Article↗
PubMed2000

Energy confinement time and heat transport in initial neutral beam heated plasmas on the large helical device

The confinement characteristics of large net-current-free plasmas heated by neutral-beam injection have been investigated in the Large Helical Device (LHD). A systematic enhancement in energy-confinement times from the scaling derived from the medium-sized heliotron/torsatron experiments have been observed, which is attributed to the edge pedestal. The core confinement is scaled with the Bohm term divided by the square root of the gyro radii. The comparative analysis using a dimensionally similar discharge in the Compact Helical System indicates gyro-Bohm dependence in the core and transport improvement in the edge region of LHD plasmas.

Journal Article↗
PubMed2000

Edge thermal transport barrier In LHD discharges

In LHD discharges a significant enhancement of the global energy confinement has been achieved for the first time in a helical device with an edge thermal barrier, which exhibits a sharp gradient at the edge of the temperature profile. Key features associated with the barrier are quite different from those seen in tokamaks: (i) almost no change in particle (including impurity) transport, (ii) a gradual formation of the barrier, (iii) a very high ratio of the edge temperature to the average temperature, and (iv) no edge relaxation phenomenon. These features are very attractive in applying the thermal barrier to future reactor grade devices.

Journal Article↗