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Altered levels of phenylalanine and its metabolites in blood and cerebrospinal fluid have previously been reported in schizophrenia. This study attempted to examine whether phenylalanine kinetics is altered in schizophrenia using the 13C-phenylalanine breath test (13C-PBT).
Subjects were 20 patients with schizophrenia and the same number of controls. 13C-phenylalanine was administered and then 13CO2 concentration in breath was monitored for 120 minutes. The Δ 13CO2 at each collecting time, the maximal Δ 13CO2 (Cmax), the time to reach Cmax (Tmax), the area under the curve of time course of Δ13CO2 (AUC), the cumulative recovery rate (CRR) at each collecting time of the 13C-PBT were calculated for each subject.
Body weight (BW) and diagnostic status were significant predictors for Cmax. BW, age and diagnostic status were significant predictors for AUC and CRR at 120 minutes (CRR0-120). A repeated measures ANCOVA controlling for age and BW revealed a different pattern of change in CRR over time between the patients and controls and that Δ13CO2 in schizophrenia were lower than that in healthy control at all sampling point during 120 min, with an overall significant differences between healthy control and schizophrenia. The ANCOVA controlling for age and BW, showed that Cmax, AUC and CRR0-120 were significantly lower in schizophrenics than in controls.
Our data indicate the different change of Δ13CO2 and CRR over time and the decreased Cmax, AUC and CRR0-120 of 13C-PBT in schizophrenia patients compared to healthy controls, suggesting the altered phenylalanine kinetics in schizophrenia.
Single-walled carbon nanotube (SWCNT) growth were carried out on SiO2/Si substrates using Pt catalysts at different temperatures, from 400°C to 700°C, under various ethanol pressures by an alcohol gas source method, a type of cold-wall chemical vapor deposition (CVD). Raman measurements showed that the optimal ethanol pressure decreased as the growth temperature was reduced, and that SWCNTs grew even at 400°C by optimizing the ethanol pressure to 1×10-5 Pa in a high vacuum system. Compared to the SWCNTs grown from Co catalysts, the diameters of SWCNTs grown from Pt were smaller, irrespective of the growth temperature. In addition, both the SWCNT diameter and the distribution became narrower by reducing the growth temperature and we obtained small-diameter SWCNTs of which the diameters were less than 1 nm using Pt catalysts.
Ti-site substitution using the higher-valent cation was performed on ferroelectric thin films of neodymium-substituted bismuth titanate, (Bi,Nd)4Ti3O12 (BNT), in order to improve its ferroelectric properties by compensating the space charge in BIT-based crystal. Ti-site-substituted BNT films, (Bi3.50Nd0.50)1-(x/12)(Ti3.00-xVx)O15 (x = 0 ∼ 0.09), were fabricated on (111)Pt/Ti/ SiO2/(100)Si substrates using a chemical solution deposition (CSD) technique. V5+-substitution enhanced the remanent polarization of BNT film without change in the coercive field. V5+-substitution also exhibited the possibilities for improving the endurance against leakage current and fatigue degradation.
To reveal the complete performance of intrinsic ferroelectriciy-related properties in single crystalline bismuth-layer-structured displacive ferroelectrics in film form on Si, the crucial roles of both orientation control technology by lattice matching from the atomic arrangement of substrate layer and configuration of the volume fraction of 90°-domain during cooling process were demonstrated. 1.2 μm-thick and Pr3+-substituted Bi4-xPrxTi3O12 (BPT, x =0.0, 0.3, 0.5, 0.7) films were grown on Ir(111)/Ti/SiO2/Si(001) substrates by chemical solution deposition (CSD) method with preferred orientation along the major component of Ps vector. BPT film of x =0.3 exhibited superb ferroelectric properties of remanent polarization 2Pr=92 μC/cm2, saturation polarization Psat=50 μC/cm2, and coercive field 2Ec=184 kV/cm. The film also showed uniform piezoelectric response with an effective piezoelectric coefficient of AFM-d33=36 pm/V. During the decomposition of precursor solutions, IrO2 layers were formed at the surface of Ir layers and promoted a/b-axes orientation. During the cooling process after grain growth, in addition, the differential thermal expansion and residual strain between film and substrate introduced bidirectional lateral stress into BPT film and might eliminate the 90°-domain walls dividing a-and b-domains through the relaxation by domain formation at the Curie temperature TC. Consequently the polar-axis orientation was distinctively grown along the film normal and the conjugate non-polar-axis was grown in-plane.
Electric-field-induced displacements of PZT film capacitor Pt/PZT(5μm)/Pt/SiO2/Si(100) were calculated by finite element method with various parameters of sample geometry: the diameter of top electrode φ TE ranging from 0.2 μ m to 1000 μ m and whether PZT film was continuous or side-etched. If φ TE was larger than 40μ m, surface longitudinal displacement (corresponding to AFM-measured strain) was not equal to net longitudinal displacement of PZT film, including a contribution of the bending motion of substrate. In contrast, if φ TE was smaller than 4μ m and PZT film was continuous, effective d33 evaluated from net longitudinal displacement was smaller than intrinsic d33, because the side PZT film clamped the edge of the capacitor disk and prevented the whole disk from elongating longitudinally. It was also revealed that d33 value calculated from net longitudinal displacement of PZT film depended on the Poisson's ratio of PZT and was not equal to intrinsic d33, excluding the case that φ TE was smaller than 4μ m and PZT film was side-etched. In conclusion, it is suggested that smaller φ TE (< 4μ m, in our case) and side-etch treatment permit a precision measurement of d33; however this condition is difficult to be satisfied experimentally.
This work presents the preliminary experimental results of Pb(ZrxTi1−x)O3 (PZT) thin films preparation to develop a new combinatorial process by chemical solution deposition (CSD) method. PZT thin films were fabricated from the PbZrO3 (PZ) and PbTiO3 (PT) multilayers on a substrate of Si/SiO2/Ti/Pt. The precursor PT and PZ solutions were coated in different sequences, (i) in the PT start sequence and (ii) in the PZ start sequence, and with different PT and PZ concentrations. It was found that the deposition sequence of PT and PZ led to the differences in composition, microstructure, texture, and ferroelectric property of the resultant thin films. The PT start deposition was suitable for preparation of the PZT thin films, while the PZ start deposition caused composition deviation and bad ferroelectric property. The postannealing had little effect for the formation of the PZT thin films from the multi-PT and PZ layers. A single perovskite phase of PZT can be obtained from the deposited multi-PT and PZ layers even without any postannealing when concentrations of the precursor PT and PZ solution are smaller than 0.025 M and the deposition sequence is in the PT start sequence. This method would be a constructive way to develop and study other thin film materials systems.
Bismuth titanate (Bi4Ti3O12; BIT) -based ferroelectric materials are proposed from the view of the “Site-engineering”, where the Bi-site ions are substituted by lanthanoid ions (La3+ and Nd3+) and Ti-site ions by other ions with higher charge valence (V5+). In the present study, influences of vanadium (V) - substitution for (Bi,M)4Ti3O12 thin films [M = lanthanoid] on the ferroelectric properties are evaluated. V-substituted (Bi,M)4Ti3O12 films have been fabricated using a chemical solution deposition (CSD) technique on the (111)Pt/Ti/SiO2/(100)Si substrate. Remnant polarization of (Bi,La)4Ti3O12 and (Bi,Nd)4Ti3O12 films has been improved by the V-substitution independent of the coercive field. The processing temperature of BLT and BNT films could also be lowered by the V-substitution.
In this study, thick sol-gel PZT(Pb(Zr1−xTix)O3) films were fabricated and their characteristics were investigated for angular rate sensor applications. The crack-free thick sol-gel PZT films were successfully deposited on silicon substrates by multiple spin-coating technique combined with rapid thermal annealing(RTA). The thickness of the PZT films is 1.5 νm, which is required by a vibration angular rate sensor for a good actuation and sensing. The remnant polarization of the PZT films is 12.0νC/cm2. The PZT films were applied to the vibration angular rate sensor structure, and the vibration of 1.78νm in amplitude at the resonant frequency of 35.8kHz was obtained. In this case, the driving voltage of 5Vp-p by bulk piezoelectric materials was applied to the driving electrode with out of phase signal through voltage and inverting amplifier.
The oscillating output voltage obtained by external actuation using a stacked piezo-actuator showed the values of 0.76V and 0.87V in outer/inner driving electrode at driving voltage of 5Vp-p.
Increases in height were reported in children chronically exposed prenatally and postnatally to D2
receptor-blocking drugs. A possible haplotypic association between stature and the DRD2 gene was
also reported. In this study, we examined linkage between stature and DRD2 by genotyping a
dinucleotide repeat polymorphism in 79 sib-pairs aged 8–17 years. An association between stature
and a putative functional polymorphism in the promoter region of the DRD2 gene was examined in
the sib-pairs and in 125 unrelated male adults. All the subjects were Japanese. Linkage (p = 0.004,
SIBPAL) and an association (p = 0.009, paired t-test, in the sib-pairs; p = 0.006, ANOVA, in the
adults) with stature were suggested. These findings indicate that DRD2 is one of the genes that
contribute to heritability of stature.
Al substitution for Zr/Ti site of PZT was attempted using a sol-gel method, and the ferroelectric properties of 200nm-thick Al doped PZT thin films were compared with those of non- doped PZT film. The leakage current of the thin films decreased with increasing Al content. Ps and Pr also decreased with increasing Al content, whereas Ec did not show a significant change. Furthermore, a simple capacitor cell structure like FeRAM was prepared using a seed layer process. The capacitor structure was Pb(Ti0.975Al0.025)O3/ Pb1.1((Zr0.52Ti0.48)0. 975Al0.025)O3/ Pb(Ti0.975Al0.025)O3, and 2Pr was 26μC/cm2. The fatigue properties of the A1 doped PZT capacitor cell showed a little improvement, because the reduction rate of the fatigue was smaller than that of non-doped PZT thin film.
C60 has not yet been detected in primitive meteorites, a finding that could demonstrate its existence in the early solar nebular or as a component of presolar dust. However, other allotropes of carbon, diamond and graphite, have been isolated from numerous chondritic samples. Studies of the isotopic composition and trace element content and these forms of carbon suggest that they condensed in circumstellar environments. Diamond may also have been produced in the early solar nebula and meteorite parent bodies by both low-temperature-low–pressure processes and shock events. Evidence for the occurrence of another carbon allotrope, with sp hybridized bonding, commonly known as carbyne, is presented.
At the same time that buckminsterfullerene was being conceived as a molecule of possible astrophysical significance, a number of much older forms of carbon were about to enjoy a new lease of life because of their discovery as presolar grains in primitive meteorites. Ever since the 1960s, it has been recognized that carbonaceous chondrites were a host for noble gases of anomalous isotopic composition (Anders 1981). The carriers of a litany of components, enjoying names such as Xe(HL) (also called CCF-Xe), s-Xe, Ne-E(L), Ne-E(H), etc., were believed to be unidentified carbon species called C∂, Cβ, Cα and C∈ respectively, themselves exhibiting unusual or exotic isotopic compositions (Swart et al. 1983a; Carr et al. 1983). In 1987, C∂ was shown to be diamond (Lewis et al. 1987) the meteorite mineral which contained Xe(HL) and nitrogen whose isotopic composition was greatly enriched in the light isotope 14N (Lewis et al. 1983).
The early prediction of hollow graphite molecules suggested that they should be supercritical under ambient conditions. This is not true of C60, but might still be true of higher fullerenes and graphite nanotubes of large diameter.
My title refers to the celebrated vision of Kekulé, one of the founders of the concept of chemical structure. In 1865, staring drowsily one evening into the fire, he saw in a dream the cyclic structure for benzene, that fundamental unit of all aromatic molecules, and of graphite and the fullerenes. In his reverie, he imagined the atoms gambolling before his eyes… ‘one of the snakes had seized hold of its own tail, and the form whirled mockingly before my eyes’ (Kekulé 1890). In this paper I deal, not so much with the recent triumphs of the identification and bulk preparation of buckminsterfullerene, as with its imaginative prehistory. This begins with Dalton's atomic theory, elaborated from 1803 onwards. Despite a very promising start, atomic theory languished for decades as merely a sort of useful metaphor. One good reason was its failure to come up with consistent atomic weights for the elements and formulae for their compounds. Whether, for example, the atomic weight of oxygen was 8 and water was HO, or whether it was 16 with water as H2O, remained uncertain for half a century.
And yet shortly after Dalton proposed his theory, the whole problem had been solved (Avogadro 1811).