Five-membered metallacyclic alkynes that have no substituents adjacent to the triple bond have been synthesized, isolated, and structurally characterized. Zirconocene dichlorides, Cp‘2ZrCl2 (Cp‘ = ...C5H5, C5H4-t-Bu), reacted with 1,4-dichlorobut-2-yne in the presence of magnesium to give 1-zirconacyclopent-3-yne compounds (5 (a) Cp‘ = C5H5, (b) Cp‘ = C5H4-t-Bu) that have a −CH2C⋮CCH2− moiety in good yields. They are stable enough to be isolated in a pure form, despite the absence of substituents. 5a reacted with an equimolar amount of Cp2Zr(but-1-ene)(PMe3) to produce a bimetallic complex in which the zirconacyclopentyne coordinates to the other zirconocene moiety as an alkyne.
This paper presents stable switching control of an radio-controlled (R/C) hovercraft that is a nonholonomic (nonlinear) system. To exactly represent its nonlinear dynamics, more importantly, to ...maintain controllability of the system, we newly propose a switching fuzzy model that has locally Takagi-Sugeno (T-S) fuzzy models and switches them according to states, external variables, and/or time. A switching fuzzy controller is constructed by mirroring the rule structure of the switching fuzzy model of an R/C hovercraft. We derive linear matrix inequality (LMI) conditions for ensuring the stability of the closed-loop system consisting of a switching fuzzy model and controller. Furthermore, to guarantee smooth switching of control input at switching boundaries, we also derive a smooth switching condition represented in terms of LMIs. A stable switching fuzzy controller satisfying the smooth switching condition is designed by simultaneously solving both of the LMIs. The simulation and experimental results for the trajectory control of an R/C hovercraft show the validity of the switching fuzzy model and controller design, particularly, the smooth switching condition.
We successfully observed deeply bound pionic 1s states in Sn isotopes (
115Sn,
119Sn,
123Sn) using the Sn(
d,
3He) pion-transfer reaction under the recoil-free condition. The 1s binding energies and ...widths were determined to high precision. The present results indicate that the isovector part of the s-wave pion-nucleus interaction is significantly enhanced, giving a clear evidence for partial restoration of chiral symmetry in the nuclear medium.
The F209L mutation alters specificity of P450coh from coumarin 7-hydroxylation to 15 alpha-hydroxylation of 11-deoxysteroids
such as testosterone and 11-deoxycorticosterone. Neither the wild-type nor ...F209L exhibits activity toward 11 beta-hydroxysteroids
including corticosterone. Mutation of Phe-209 to Asn, however, confers on mutant F209N a high corticosterone 15 alpha-hydroxylase
activity. F209V also exhibits low corticosterone 15 alpha-hydroxylase activity; Km and Vmax are 10-fold higher and lower,
respectively, than for F209N. The results are consistent with the hypothesis that direct interaction of Asn-209 with 11OH
is responsible for high corticosterone 15 alpha-hydroxylase activity. To support this hypothesis, a possible steroid-binding
orientation is modeled in the substrate pocket of P450cam. Our weighted homology and constrained alignments map residue 209
of P450coh to Met-184 and Met-191 of P450cam. Energy minimization of corticosterone in the substrate pocket results in the
11OH of the steroid directed toward Met-184 (7 A) and Met-191 (16 A), and in C15 located near the sixth axial position of
the heme. The steroid-binding model suggests that the P450cam's substrate pocket may be conserved in the mammalian P450 and
can accommodate a steroid molecule, and that residue 209 appears to be located at the critical site that determines the steroid-substrate
specificity of a P450 depending on the type of group at the 11-position of steroid molecule.
Morphological types of arbuscular mycorrhizal (AM) fungi in roots of understorey plants were examined in three different Japanese deciduous broadleaved forests. In total, 43 species belonging to 33 ...genera from 27 families were examined for the morphological types of AM. The number of flowering plant species having Paris-type AM was greater than those having Arum-type AM in each plot. This tendency was more prominent in herbaceous plants than woody plants with nine species having Paris-type associations among ten herbaceous plant species examined. Therefore, it is suggested from the ecological point of view that Paris-type associations could be advantageous for the herbaceous understorey plants growing slowly in these environments. The influence of plant identity on the morphological types of AM was also discussed by arranging the plants examined with the morphological types in a current plant phylogeny scheme. In this study, some new records on the morphological types of AM in some new plant families were obtained including the first report of a typical Arum-type AM in gymnosperms.
Eu2+-doped inorganic-organic hybrid materials, which are potentially suitable for a tunable laser in the near ultra violet and blue region, were prepared through the photoreduction of Eu3+ ions in ...the materials under the irradiation of the fourth harmonic wave light (266 nm) of the Nd:YAG laser. The hybrid materials doped with Eu3+ ions were prepared from Si(OCH3)4, CH3Si(OCH3)3, EuCl3 and chloropropyltrimethoxysilane (CPTM). After the prehydrolized silica sol was added to the Eu3+-containing solution, Eu3+-doped transparent inorganic-organic hybrid material was obtained by drying at 50°C. The emission peak around 450–475 nm due to the charge transfer transition (5d-4f) of Eu2+ ions increased with the laser irradiation time. Eu3+ ions were effectively photoreduced to Eu2+ ions in pore-free materials prepared at high CPTM to Eu3+ ratios. Eu2+ ions were generated by the photodecomposition of the bond between Eu3+ and Cl (Cl− or Cl(CH2)3 in CPTM).
Although many studies have examined associations between single nucleotide polymorphisms (SNPs) in the CYP1A1, CYP1A2 and CYP1B1 genes and breast cancer risk, no study has examined functional SNPs in ...the CYP3A5 gene and only a small number of studies have been investigated in Japanese populations. To examine the association between six SNPs, CYP1A1(*)2A, CYP1A1(*)2C, CYP1A2(*)1F, CYP1B1 Arg(48)Gly, CYP1B1 Leu(432)Val and CYP3A5*3 and breast cancer risk, therefore, we conducted hospital-based case-control studies in Nagano, Japan and São Paulo, Brazil including 873 pairs (403 Japanese (JJ), 81 Japanese Brazilians (JB) and 389 non-Japanese Brazilians (NJB)). Although we found no significant association in the three populations combined, subgroup analyses revealed statistically significant associations of CYP1A2*1F in NJB, and CYP1B1 Leu(432)Val and CYP3A5*3 in JJ with breast cancer risk. Compared to women with the AA genotype in CYP1A2*1F, the odds ratio (OR) (95% confidence interval (CI)) for NJB with the CC genotype was 0.54 (0.32-0.90); that for JJ with Leu/Val+Val/Val versus Leu/Leu genotype in CYP1B1 Leu(432)Val was 0.68 (0.48-0.97); and that for JJ with (*)3/(*)1+(*)1/(*)1 versus (*)3/(*)3 genotype in CYP3A5*3 was 1.49 (1.10-2.04). Our findings provide further evidence that genetic polymorphisms related to estrogen metabolism may play a role in the development of breast cancer.
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