Showing papers by "Waseda University published in 1992"
TL;DR: Results indicate that defects responsible for these luminescence bands are diamagnetic defects introduced during preparation or paramagnetic species induced during excitation.
Abstract: Photoluminescence under 7.9-eV excimer-laser excitation was measured at room temperature on various types of high-purity silica glasses, which were classified based on the oxygen stoichiometry and OH concentrations. Several luminescence bands with different peak energies from 1.9 to 4.3 eV and decay constants were observed in different types of silicas. The 1.9-eV band was observed in low-OH oxygen-surplus and high-OH silicas. The 2.7-eV band was observed only in low-OH oxygen-deficient silicas. The 3.1- and the 4.2-eV bands were observed in a particular type of silica, which has a characteristic absorption band at 5.1 eV (referred to as the ${\mathit{B}}_{2}$\ensuremath{\beta} band). The 4.3-eV band was observed in all types of silicas but the oxygen-surplus type. These results indicate that defects responsible for these luminescence bands are diamagnetic defects introduced during preparation or paramagnetic species induced during excitation.
369 citations
TL;DR: In this paper, the authors investigated the role of hard limestone on the pedoclimate of terra rossa and found that the processes of rubification and vermiculitization could have taken place at the same time.
Abstract: Terra rossa samples were taken from the B horizons of soil profiles and from cracks within limestone in Italy. The average annual temperature (AAT) of the sites ranged from 8.4 to 20.3°C and the average annual precipitation (AAP) from 511 to 3113 mm, with either a 5–6 month water deficit or a large water surplus. Goethite and hematite were identified in all the samples. Under a moist (> 1700 mm AAP) and cool (13°C AAT) climate, a xeric, hematitic pedoenvironment was preserved by the well-litified carbonate rock. Hematite occurred in trace amounts, even with an AAT of 8.4°C and an AAP of 3300 mm, confirming the specific role of the hard limestone on the pedoclimate of terra rossa. The lowest mean crystallite dimension of goethite and hematite was found in the samples from the wettest sites, and in these samples hematite was nearly free of Al substitution. Rubification in terra rossa appeared to be due to the specific pedoenvironment. The hematite cannot be considered a relict phase formed under another climate. Illite and kaolinite were the main clay minerals in samples from xeric sites whereas more weathered clays, such as Al-interlayered vermiculite, occurred in cool, moist sites. We postulate that the processes of rubification and vermiculitization could have taken place at the same time. The effects of layer charge magnitude and location on expansion were represented by an energy change (expansion energy: ΔEr) during the hydration and solvation processes. Plots of basal spacings versus ΔEr show a reasonable relationship; the spacings generally decrease stepwise as the value of ΔEr increases. The basal spacings of K-samples with glycerol solvation, Na-saturated and K-saturated samples at 100% RH are apt to contract stepwise with increasing value of ΔEr. For these samples, the figures showing the relationship between each expanded phase and the charge characteristics are obtained from the isoquants of ΔEr, given the boundary of the expanded phases. A behavior test using these figures may be combined with the Greene-Kelly test to estimate the amount and the location of the layer charge of common smectites.
313 citations
TL;DR: Results indicate that FlgM is a novel type of negative regulator that probably inactivates the flagellum‐specific sigma factor through direct interaction, i.e. it is an anti‐sigma factor.
Abstract: Summary
We have studied the molecular mechanism of the negative regulation by flgM of the late operons of the flagellar regulon of Salmonella typhimurium. A 7.8 kDa protein that was identified as the flgM gene product was purified to homogeneity; its amino-terminal sequence was identical to the deduced sequence except for the lack of the initiating methionine. The purified FlgM repressed transcription from the fliC promoter, one that is activated by the sigma factor, FliA (σF). No DNA-binding activity was detected in FlgM. Chemical cross-linking experiments showed that the purified FlgM bound to σF and disturbed Its ability to form a complex with RNA polymerase core enzyme. These results indicate that FlgM is a novel type of negative regulator that probably inactivates the flagellum-specific sigma factor through direct interaction, i.e. it is an anti-sigma factor.
239 citations
TL;DR: In this article, the asymptotic behavior of the rarefaction wave of the solution of a one-dimensional barotropic model system for compressible viscous gas was studied.
Abstract: This paper is concerned with the asymptotic behavior toward the rarefaction wave of the solution of a one-dimensional barotropic model system for compressible viscous gas. We assume that the initial data tend to constant states atx=±∞, respectively, and the Riemann problem for the corresponding hyperbolic system admits a weak continuous rarefaction wave. If the adiabatic constant γ satisfies 1≦γ≦2, then the solution is proved to tend to the rarefaction wave ast→∞ under no smallness conditions of both the difference of asymptotic values atx=±∞ and the initial data. The proof is given by an elementaryL
2-energy method.
194 citations
TL;DR: Judging from the PSG recordings, ISP differs from other dissociated states such as lucid dreaming, nocturnal panic attacks and REM sleep behavior disorders.
Abstract: We elicited isolated sleep paralysis (ISP) from normal subjects by a nocturnal sleep interruption schedule. On four experimental nights, 16 subjects had their sleep interrupted for 60 minutes by forced awakening at the time when 40 minutes of nonrapid eye movement (NREM) sleep had elapsed from the termination of rapid eye movement (REM) sleep in the first or third sleep cycle. This schedule produced a sleep onset REM period (SOREMP) after the interruption at a high rate of 71.9%. We succeeded in eliciting six episodes of ISP in the sleep interruptions performed (9.4%). All episodes of ISP except one occurred from SOREMP, indicating a close correlation between ISP and SOREMP. We recorded verbal reports about ISP experiences and recorded the polysomnogram (PSG) during ISP. All of the subjects with ISP experienced inability to move and were simultaneously aware of lying in the laboratory. All but one reported auditory/visual hallucinations and unpleasant emotions. PSG recordings during ISP were characterized by a REM/W stage dissociated state, i.e. abundant alpha electroencephalographs and persistence of muscle atonia shown by the tonic electromyogram. Judging from the PSG recordings, ISP differs from other dissociated states such as lucid dreaming, nocturnal panic attacks and REM sleep behavior disorders. We compare some of the sleep variables between ISP and non-ISP nights. We also discuss the similarities and differences between ISP and sleep paralysis in narcolepsy.
145 citations
139 citations
TL;DR: It is suggested that the drug in the polymeric matrices diffused from the inside to the surface during the 'off' state even when no drug release was seen, to clarify the role of the surface-modulated skin and controlled pulsatile drug release patterns.
Abstract: Thermosensitive co-polymers of isopropyl acrylamide (IPAAm) with butyl methacrylate (BMA) are capable of 'on-off' regulation of drug release in response to external temperature changes due to skin formation with increasing temperature. To clarify the role of the surface-modulated skin and controlled pulsatile drug release patterns, the surface shrinking process was regulated by changing the length of the methacrylate alkyl side-chain. Release of indomethacin in response to stepwise temperature changes between 20 and 30 degrees C from co-polymers of IPAAm with BMA, hexyl methacrylate (HMA), and lauryl methacrylate (LMA) was studied. The drug release rate during the 'on' state (20 degrees C) remained constant before and after the 'off' state (30 degrees C) when the period of the 'off' state was increased. These results suggest that the drug in the polymeric matrices diffused from the inside to the surface during the 'off' state even when no drug release was seen. The length of alkyl side-chain was found to be an important parameter in controlling the thickness and density of the surface skin layer.
132 citations
TL;DR: It is suggested that LHRH neurons of the newt, Cynops pyrrhogaster, originate in the olfactory placode and then migrate into the brain during embryonic development.
Abstract: Neurons containing luteinizing hormone-releasing hormone (LHRH) are first detected in newt embryos (Cynops pyrrhogaster) in the olfactory epithelium and ventromedial portion of the olfactory nerve, after which they sequentially appear in the intracerebral course of the terminal nerve at prometamorphosis, and in the septo-preoptic area at postmetamorphosis. In adults, however, LHRH-immunoreactive cells are rarely seen in the nasal region, and their distribution shifts into the brain, suggesting their migration. In order to ascertain the origin and possible migration route of these neurons in newt larvae, the effect of unilateral or bilateral olfactory placodectomy on the LHRH neuronal system has been studied. Removal of the olfactory placode results in the absence of LHRH-immunoreactive cells in the nasal and brain regions of the operated side, whereas the subsequent growth and the LHRH-immunoreactive cellular distribution in the contralateral side are identical to those of normal larvae. Following bilateral placodectomy, no LHRH immunoreactivity is detected on either side of the olfactory-brain axis. These results suggest that LHRH neurons of the newt, Cynops pyrrhogaster, originate in the olfactory placode and then migrate into the brain during embryonic development.
131 citations
TL;DR: In this paper, the authors investigated the hydrolysis and initial polycondensation processes of methyltriethoxysilane (MTES) by high-resolution 29Si-nuclear magnetic resonance spectroscopy (29Si-NMR).
Abstract: The hydrolysis and initial polycondensation processes of methyltriethoxysilane (MTES) have been investigated by high-resolution 29Si-nuclear magnetic resonance spectroscopy (29Si-NMR). MTES was hydrolyzed in the system with MTES:ethyl alcohol:water:HCL = 1:4:x:y; x = 1, 2, 3, 6; y = 1 × 10−4, 1 × 10−2. Signals due to end and middle groups of polysiloxanes formed sub-regions on the basis of the number of hydroxyl groups attached to silicon, and the sub-region for silicon possessing more hydroxyl groups was observed at a lower field. Based on signal intensities, the signals due to the dimers (Me(HO)2SiOSi(OH)2Me and Me(HO)2SiOSi(OH)OEt)Me) and the trimer (Me(HO)2SiOSiMe(HO)OSi(OH)2Me) (MeCH3, EtC2H5) were identified.
130 citations
TL;DR: It is found that the isotropic power-law solution is the unique attractor for any initially expanding Bianchi-type models except type IX, and this conclusion is also true if the initial ratio of the vacuum energy to the maximum three-curvature is larger than one half.
Abstract: We prove a cosmic no-hair theorem for Bianchi models in power-law inflation. Provided that the potential of an inflaton {phi} is exp({minus}{lambda}{kappa}{phi}) with 0{le}{lambda}{lt} {radical}2/3 , we find that the isotropic power-law solution is the unique attractor for any initially expanding Bianchi-type models except type IX. For Bianchi type IX, this conclusion is also true if the initial ratio of the vacuum energy to the maximum three-curvature is larger than one half.
129 citations
TL;DR: It is reported that pros encodes a nuclear protein containing a homeodomain-like sequence, suggesting a post-transcriptional control of pros expression in neuronal lineages of the central nervous system.
TL;DR: In this article, it was shown that every element of ℱ1(M) satisfies Axiom A. This conjecture was later proved to be true in the context of the C1 Stability Conjecture.
Abstract: R. Mane has given a proof of the C1 Stability Conjecture and conjectured that every element of ℱ1(M) satisfies Axiom A. Here we prove that this conjecture is true.
TL;DR: In this paper, cDNA clones for two types of proteases (HCE, LCE) were isolated from a lambda gt11 cDNA library constructed with poly(A)+ RNA of Day 3 embryos.
TL;DR: The results suggest that LHRH neurons originate in the olfactory placode and then migrate into the forebrain along theOlfactory nerve, whereas the development of the L HRH neuronal system was not disturbed on the unoperated side.
07 Jul 1992
TL;DR: In this paper, the invariants of 3-manifolds τr(r>3) were studied explicitly, and the authors showed that τ3(M) can be written as follows.
Abstract: Introduction. In [16], R. Kirby and P. Melvin study invariants of 3manifolds τr(r>3) introduced by E. Witten [38], N. Reshetikhin and V.G. Turaev [31], and W.B.R. Lickorish [25, 26, 27] (see also [18]). In particular, Kirby and Melvin calculated τ3 and τ4 explicitly. Let M be a closed, oriented 3-manifold obtained from an (integral) framed link L. Then τ3(M) can be written as follows [16, §6].
TL;DR: The first mixed-valent octanuclear platinum blue compounds with bridging acetamidate and 2-fluoroacetamidate ligands were crystallographically characterized in this article.
Abstract: The first mixed-valent octanuclear platinum blue compounds with bridging acetamidate and 2-fluoroacetamidate ligands, [(H 3 N) 2 Pt(CH 3 CONH) 2 Pt(NH 3 ) 2 ] 4 (NO 3 ) 10 .4H 2 O and [(H 3 N) 2 Pt(CH 2 FCONH) 2 Pt(NH 3 ) 2 ] 4 (NO 3 ) 8.66 .4H 2 O, are crystallographically characterized.
07 Jul 1992
TL;DR: A learning control algorithm of the com- pensative trunk motion that makes the actual ZMP get closer to the desired ZMP is proposed.
Abstract: The authors have been using the ZMP (Zero Mo- ment Point) as a criterion to distinguish the stability of walk- ing for a biped walking robot that has a trunk. In this paper, the authors propose a learning control algorithm of the com- pensative trunk motion that makes the actual ZMP get closer to the desired ZMP. The convergency of the algorithm is con- firmed by computer simulation and learning experiments with the biped robot. The change of the convergence rate with the change of the weight coefficient multiplied to the errors be- tween the measured ZMP and the desired ZMP is confirmed by the simulation and the experiments. And also the reasons are discussed.
TL;DR: In this paper, the stages of voltage collapse in a power system are described, and circuit and system techniques for analyzing voltage collapse that relate it to the changing number of solutions for the power flow equations, due to slow changes in system parameters are presented.
Abstract: The stages of a voltage collapse in a power system are described. Circuit and system techniques for analyzing voltage collapse that relate it to the changing number of solutions for the power-flow equations, due to slow changes in system parameters are presented. It is shown that to fully analyze voltage collapse for small- and large-disturbance cases, the essential dynamic mechanisms are considered. Several algorithms developed to detect how close a system is to voltage collapse are discussed. A voltage-collapse scenario based on the interaction among dynamic mechanisms is outlined. >
TL;DR: In this article, a kaolinite-poly intercalation compound has been prepared by the interalation of an N-vinyl-2-pyrrolidone monomer (VP) and subsequent heat treatment.
Abstract: A kaolinite-poly (vinylpyrrolidone) intercalation compound has been prepared by the intercalation of an N-vinyl-2-pyrrolidone monomer (VP) and subsequent heat treatment. The intercalation of VP was achieved by treating a kaolinite-ammonium acetate intercalation compound with a VP aqueous solution. The basal spacing decreased from 14.2 to 12.6A, and infra-red spectroscopy (IR) and solid-state 13C nuclear magnetic resonance with cross polarization and magic angle spinning techniques (13C CP/MAS NMR) showed the displacement of ammonium acetate by VP. When the kaolinite-VP intercalation compound was heated at 200°C for 1h, the basal spacing did not vary. The IR and 13C CP/MAS NMR spectra showed the disappearance of vinyl groups and became similar to those of poly (vinylpyrrolidone) (PVP). These results clearly indicate the polymerization of VP between the layers of kaolinite.
TL;DR: Fairly good agreement with experiment has been obtained with respect to the relative variation of the scintillation yield with LET using a diffusion-reaction model of free excitons with a specific reaction rate within acceptable limits.
Abstract: A theoretical model is presented for the linear-energy-transfer (LET) variation of the relative scintillation yield in liquid argon. It is based on energy partition between the core and the penumbra of the charged particle track with little quenching in the penumbra except for fission fragments. Scintillation from the core can be quenched significantly by a biexcitonic mechanism. Some detailed calculations indicate that the electron-ion recombination may occur before exciton self-trapping. Fairly good agreement with experiment has been obtained with respect to the relative variation of the scintillation yield with LET using a diffusion-reaction model of free excitons with a specific reaction rate within acceptable limits. At the same LET different heavy-ion tracks can develop different quenching ratios depending on the density of deposited energy in the core.
TL;DR: In this paper, a solid-solid reaction between dodecyltrimethylammonium-montmorillonite and anthracene gave only partly intercalated compounds.
Abstract: Intercalation of naphthalene and anthracene into alkyltrimethylammonium (C, H2. + ~ (CH3)3N+; n = 8, 12, 14, 16, and 18)-montmorillonites was carried out by novel solid-solid reactions at room temperature. Octyltrimethylammoniurn(C8)-montmorillonite did not form an intercalation compound with either naphthalene or anthracene. Naphthalene was intercalated into both dodecyltrimethylam- monium(C12)- and octadecyltrimethylammonium(C18)-montmorillonites to give intercalation com- pounds. On the other hand, the solid-solid reaction between dodecyltrimethylammonium(C 12)- or tetra- decyltrimethylammonium(C 14)-montmorillonite and anthracene gave only partly intercalated compounds while hexadecyltrimethylammonium(C16)- and octadecyltrimethylammonium(C18)-montmorillonites gave single phase intercalation compounds. The hydrophobic interactions between alkytammonium- montmorillonites and the aromatic compounds are thought to be the driving force for the solid-state intercalation. The extent of the increase in the basal spacing may also be involved in the different reactivity.
TL;DR: In this article, an overview of carbon-oxygen bond cleavage reactions promoted by transition metal complexes is provided, particularly the conceptual and mechanistic aspects of C-0 bond activation.
Abstract: Publisher Summary This chapter provides an overview of Carbon–0xygen bond cleavage reactions promoted by transition metal complexes, particularly the conceptual and mechanistic aspects of C–0 bond activation by transition metal complexes. Carbon–oxygen single bonds as well as carbon–oxygen double bonds may be cleaved by transition metal complexes. The chapter deals with the cleavage of the carbon–oxygen single bonds in organic compounds and treats the carbon–oxygen double-bond cleavage later. Two types of processes have been recognized regarding allylic oxygen bond cleavage. One is the process giving products, resulting from the net oxidative addition of allylic compounds and the other is the consecutive-type process initiated by transition metal complexes having ligands such as hydride, alkyl, or alkoxide that may add to the allylic double bond to cause reactions. The C–0 bond cleavage of alkenyloxiranes to π-ally1 complexes can be accomplished with transition metal complexes other than palladium. For example, on treatment of alkenyloxiranes with iron, cobalt, or manganese carbonyls, various η3 allyloxycarbonycl omplexes have been obtained.
TL;DR: It was shown that the total intensity noise of a pump-noise-suppressed multimode semiconductor laser was reduced to below the standard quantum limit even though the intensity Noise of each individual mode had large excess intensity noise.
Abstract: The intensity-noise properties of a constant-current-driven multimode semiconductor laser were studied theoretically and experimentally. It was shown that the total intensity noise of a pump-noise-suppressed multimode semiconductor laser was reduced to below the standard quantum limit even though the intensity noise of each individual mode had large excess intensity noise. This discovery stems from negative quantum correlations between longitudinal-mode intensities.
TL;DR: In this article, Magadiite and K-kenyaite were synthesized after 16h at 185°C from a suspension with molar ratios of H2O/SiO2=18.95-23.23 and NaOH/K2CO3=0.23, respectively.
Abstract: In order to synthesize well-crystallized magadiite and kenyaite as a single phase in a short reaction time, amorphous silica was hydrothermally reacted with alkaline solutions in the temperature range from 150°C to 200°C. From a suspension containing SiO2 and NaOH with molar ratios of H2O/SiO2=18.5 and NaOH/SiO2=0.23, magadiite was formed after a reaction time of 48 h at 150°C or after 18h at 170°C. The formation of Na-kenyaite, however, required 6h at 200°C. Then, KOH and K2CO3 were used to lower the formation temperature of kenyaite. K-kenyaite was synthesized after 16h at 185°C from a suspension with molar ratios of H2O/SiO2=18.5 and KOH/SiO2=0.23. Furthermore, (Na, K)-kenyaite was formed after 48h at 150°C or after 24h at 170°C from suspensions with molar ratios of H2O/SiO2=18.5, NaOH/SiO2=0.23 and NaOH/K2CO3=0.95-23. Magadiite and kenyaite were formed through a difinite induction period after dissolution of amorphous silica.
TL;DR: In this article, the characteristics of cosmic-ray hadronic interactions in the 1015 − 1017 eV range were studied by observing a total of 429 families of visible energy greater than 100 TeV found in emulsion chamber experiments at high mountain altitudes.
TL;DR: The present study suggests the expression of at least two types of metabotropic receptors in the Purkinje cell region, one of which is a t-ACPD-sensitive receptor expressed on the presynaptic terminals of the neurons making synapses onto Purkinjen cells, but relatively insensitive to QA.
TL;DR: In this paper, an infinite-dimensional R matrix related to the limiting case n→∞ of the completely ℤn symmetric R matrix is discovered, expressed as an operator on C∞(S1×S1).
Abstract: An infinite-dimensional R matrix related to the limiting case n→∞ of the completely ℤn symmetric R matrix is discovered. This R matrix is expressed as an operator on C∞(S1×S1). Moreover, the fusion procedure of the R-operator is investigated and the finite-dimensional R matrices are constructed from the R operator.
TL;DR: It is found that the tension of myofibrils spontaneously oscillates accompanied by the oscillation of sarcomere length with a main period of a few seconds, under the condition of MgATP, MgADP and inorganic phosphate without free Ca2+.