共查询到20条相似文献,搜索用时 15 毫秒
1.
Alexander J. Blake Paul J. Dyson Scott L. Ingham Brian F. G. Johnson Caroline M. Martin 《Inorganica chimica acta》1995,240(1-2):29-32
The new organometallic cluster (η2-μ4-CO)2(CO)13(η6-C6Me6) has been prepared by the thermolysis of Ru3(CO)12 with hexamethylbenzene in octane and characterised by a single crystal X-ray diffraction study. It is isostructural with the known cluster Ru6(η2-μ4-CO)2(CO)13(η6-C6H3Me3) and the metal core constitutnts the same tetrahedral Ru4 unit with two edge-bridging Ru atoms. The mesitylene derivative has been shown to undergo rearrangement to afford the octahedral carbido cluster Ru6C(CO)14(η6-C6H3Me3), but this conversion is not observed for the new hexamethylbenzene derivative. 相似文献
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A. M. Cano J. Cano T. Cuenca P. Gmez-Sal A. Manzanero P. Royo 《Inorganica chimica acta》1998,280(1-2):1
The reaction of TiCl4 with Li2[(SiMe2)2(η5-C5H3)2] in toluene at room temperature afforded a mixture of cis- and trans-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] in a molar ratio of 1/2 after recrystallization. The complex trans-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] was hydrolyzed immediately by the addition of water to THF solutions to give trans-[(TiCl2)2(μ-O){(SiMe2)2(η5-C5H3)2}] as a solid insoluble in all organic solvents, whereas hydrolysis of cis-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] under different conditions led to the dinuclear μ-oxo complex cis-[(TiCl2)2)(μ-O){(SiMe2)2(η5-C5H3)2}] and two oxo complexes of the same stoichiometry [(TiCl)2(μ-O){(SiMe2)2(η5-C5H3)2}]2(μ-O)2 as crystalline solids. Alkylation of cis- and trans-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] with MgCIMe led respectively to the partially alkylated cis-[(TiMe2Cl)2{(SiMe2)2(η5-C5H3)2}] and the totally alkylated trans-[(TiMe3)2{(SiMe2)2(η5-C5H3)2}] compounds. The crystal and molecular structure of the tetranuclear oxo complex [(TiCl)2(μ-O){(SiMe2)2(η5-C5H3)2}]2(μ-O)2 was determined by X-ray diffraction. 相似文献
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With exposure to trace amounts of air and moisture, the Cr2(II, II) complex Cr2(μ-3,5Cl2-form)4, where 3,5Cl2-form is [(3,5-Cl2C6H3)NC(H)N(3,5-Cl2C6H3)−], undergoes an oxidative addition reaction. Structural information from the X-ray crystal structure of the edge-sharing bioctahedral (ESBO) Cr2(III, III) product Cr2(μ-OH)2(μ-3,5Cl2-form)2(η2-3,5Cl2-form)2 (1) indicates 1 has a significantly longer Cr–Cr distance [2.732(2) Å] than Cr2(μ-3,5Cl2-form)4 [1.9162(10) Å], but the shortest Cr–Cr distance in an ESBO Cr2(III, III) complex recorded to date. 相似文献
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We demonstrated previously that an α1—β2—γ2 gene cluster of the γ-aminobutyric acid (GABAA) receptor is located on human chromosome 5q34–q35 and that an ancestral α—β—γ gene cluster probably spawned clusters on chromosomes 4, 5, and 15. Here, we report that the α4 gene (GABRA4) maps to human chromosome 4p14–q12, defining a cluster comprising the α2, α4, β1, and γ1 genes. The existence of an α2—α4—β1—γ1 cluster on chromosome 4 and an α1—α6—β2—γ2 cluster on chromosome 5 provides further evidence that the number of ancestral GABAA receptor subunit genes has been expanded by duplication within an ancestral gene cluster. Moreover, if duplication of the α gene occurred before duplication of the ancestral gene cluster, then a heretofore undiscovered subtype of α subunit should be located on human chromosome 15q11–q13 within an α5—αx—β3—γ3 gene cluster at the locus for Angelman and Prader—Willi syndromes. 相似文献
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M.D. Nelson Burton Shirley Carlile M.D. William Jubiz 《Prostaglandins & other lipid mediators》1975,10(6):667-674
Plasma prolactin and F-prostaglandins (PGF) were measured in anesthetized male Sprague-Dawley rats before and at 15, 30, 45 and 60 minutes following i.v. injection of either PGF2α (4 mg/kg), chlorpromazine, 1 mg/kg or chlorpromazine (1 mg/kg) after pretreatment with i.p. indomethacin (2 mg/kg). Following PGF2α administration, plasma prolactin levels increased significantly only at 15 and 30 minutes in spite of extremely high PGF levels throughout 60 minutes. Besides the expected rise in plasma prolactin, chlorpromazine caused a transient but statistically significant increase in PGF. Indomethacin blocked the chlorpromazine-induced PGF rise but not prolactin increase. Animals stressed with ether anesthesia showed elevation of plasma prolactin, which was not blocked by indomethacin although PGF concentration fell. These results indicate that PGF2α can stimulate prolactin release. This effect does not appear to be physiologic since very high PGF levels are required. Furthermore, blockade of prostaglandin synthesis by indomethacin does not prevent the release of prolactin in response to chlorpromazine or stress. Our findings do not support a possible role of PGFs as intermediaries in prolactin release. However, it is possible that PGFs may work through other mechanisms not investigated in our study. 相似文献
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The α1 subunit genes encoding voltage-dependent Ca2+ channels are members of a gene family. We have used human brain cDNA probes to localize the neuronal isoform genes CACNL1A4 (α1A), CACNL1A5 (α1B), and CACNL1A6 (α1E) to 19p13, 9q34, and 1q25-q31, respectively, using fluorescence in situ hybridization on human chromosomes. These genes are particularly interesting gene candidates in the pathogenesis of neuronal disorders. Although genetic disorders have been linked to loci 9q34 and 19p13, no genetic disease related to Ca2+ signaling defects has yet been linked to these loci. 相似文献
9.
M.S. Ameerunisha Begum Oliver Seewald Ulrich Flrke Gerald Henkel 《Inorganica chimica acta》2008,361(7):1868-1874
Copper(I) complexes with {Cu(μ2-S)N}4 and {Cu(μ3-S)N}12 core portions of butterfly-shaped or double wheel architectures have been isolated in the reaction of Cu(I) with the Schiff base ligand C6H4(CHNC6H4S)2, “iso-abt”, under different conditions. containing the tetranuclear electroneutral complex is formed by the reaction of CuI in acetonitrilic solution and recrystallization from DMF, whereas containing dodecanuclear wheels is accessible starting from CuBF4. Complexes 2 and 4 represent the first examples of cyclic complexes with the same overall stoichiometry but different ring sizes. The ligand induces two different coordination environments around copper(I) by switching between μ2- and μ3-sulfur bridging modes. 相似文献
10.
Claudia Graiff Andrea Ienco Chiara Massera Carlo Mealli Giovanni Predieri Antonio Tiripicchio Franco Ugozzoli 《Inorganica chimica acta》2002,330(1):95-102
The reaction between the linear trinuclear complex [Pt{Fe(CO)3(NO)}2(PhCN)2] and Ph2(2-C5H4N)PSe led to the isolation and characterization of the 46-electron cluster [(CO)3Fe(μ3-Se){Pt(CO)P(2-C5H4N)Ph2}2] (1), whose structure has been determined by X-ray diffraction methods. The cluster typology, which consists of an open triangle Pt---Fe---Pt capped by a μ3-Se atom, is rather rare. The chemical bonding in 1 and in similar systems has been analyzed through density functional theory (DFT) and qualitative MO approaches. A strict analogy with the well understood L2M(μ-acetylene)ML2 systems is invoked by considering 1 as formed by the (CO)3FeSe tetrahedral unit stabilized by sidewise interactions of the triple bond with two d10-L2M fragments. Otherwise, the 18-electron (CO)3FeSe monomer is unstable as an isolate molecule. This is confirmed by our DFT calculations that indicate how the well characterized dimer (CO)3Fe(μ-Se2)Fe(CO)3 lies as much as, approximately, 58 kcal mol−1 deeper in energy. Finally, by considering an analogy with [L2M(μ-dichalcogen)ML2]0, +2 redox systems (M=Pd, Pt), reduction of 1 to a dianion has been hypothesized and the structure of the latter has been tentatively explored by DFT calculations. 相似文献
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The preparation and structural characterization of {Ru3(CO)11}2(1,4-bis(diphenylphosphino)benzene), a modified synthesis of 1,4-bis(diphenylphosphino)benzene, and the structural characterization of {Ru3(CO)11}2(bis(diphenylphosphino)ethane) are reported. In both compounds two metal cluster units are connected through ditertiary-phosphine ligands. Both molecules consist of centrosymmetric units in which the diphosphine ligands are largely covered by the triangular ruthenium clusters. No direct interaction between the two cluster units occurs within individual molecules. Molecular packing in the solid state is dominated by interactions between sets of carbon monoxide ligands in motifs that were previously identified in the solid state structure of the parent cluster, Ru3(CO)12. 相似文献
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Prostaglandin (PG)F2α, E2, D2 and 6-keto-F1α were determined in human cerebrospinal fluid by a mass spectrometric technique. The samples were obtained from 12 patients with suspected intracranial disease. A 64 fold variation in PG levels was observed. The major PG was 6-keto-F1α (0.12–15 ng/ml). PGF2α and PGE2 were present in lower concentrations PGD2 was below the level of detection (0.05 ng/ml) except in one patient with extremely high total levels of PGs. 相似文献
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Our reported data on the cortical inhibitory actions of prostaglandin F2α (PGF2α) and the diversity of data in the literature on cerebral PG actions are examined here in the light of intracellular recording which provides the requisite membrane data for the first time. Thus, 1) intracellular recording from the cat cerebral cortex is obtained for the actions of PGF2α and for norepinephrine (NE) and serotonin (5HT). 2) The parallel changes in firing and polarization and the simultaneous transmembrane conductance changes are qualitatively identical for PGF2α, NE and 5HT. 3) The reduction in firing accompanied by hyperpolarization indicates that PGF2α, NE and 5HT all inhibit these cells. 4) The ionic species responsible for this inhibition is such that it increased the transmembrane resistance, and this was true for all three. 5) The changes in membrane parameters, identical in direction for PGF2α and NE, but stronger for the latter, constitute conditions that can lead to competitive inhibition and therefore conote, presumably, actions at the same or related receptors. Such competition with evoked cortical field potentials is shown in the preceding paper. 相似文献
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Franoise Maupas-Schwalm Aurlie Bedel Nathalie Aug Marie-Hlne Grazide Elodie Mucher Jean-Claude Thiers Robert Salvayre Anne Ngre-Salvayre 《Cellular signalling》2009,21(12):1925-1934
Plasminogen activators are implicated in the pathogenesis of several diseases such as inflammatory diseases and cancer. Beside their serine-protease activity, these agents trigger signaling pathways involved in cell migration, adhesion and proliferation. We previously reported a role for the sphingolipid pathway in the mitogenic effect of plasminogen activators, but the signaling mechanisms involved in neutral sphingomyelinase-2 (NSMase-2) activation (the first step of the sphingolipid pathway) are poorly known. This study was carried out to investigate how urokinase plasminogen activator (uPA) activates NSMase-2. We report that uPA, as well as its catalytically inactive N-amino fragment ATF, triggers the sequential activation of MMP-2, NSMase-2 and ERK1/2 in ECV304 cells that are required for uPA-induced ECV304 proliferation, as assessed by the inhibitory effect of Marimastat (a MMP inhibitor), MMP-2-specific siRNA, MMP-2 defect, and NSMase-specific siRNA. Moreover, upon uPA stimulation, uPAR, MT1-MMP, MMP-2 and NSMase-2 interacted with integrin αvβ3, evidenced by co-immunoprecipitation and immunocytochemistry experiments. Moreover, the αvβ3 blocking antibody inhibited the uPA-triggered MMPs/uPAR/integrin αvβ3 interaction, NSMase-2 activation, Ki67 expression and DNA synthesis in ECV304. In conclusion, uPA triggers interaction between integrin αvβ3, uPAR and MMPs that leads to NSMase-2 and ERK1/2 activation and cell proliferation. These findings highlight a new signaling mechanism for uPA, and suggest that, upon uPA stimulation, uPAR, MMPs, integrin αvβ3 and NSMase-2 form a signaling complex that take part in mitogenic signaling in ECV304 cells. 相似文献
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Zhang Xiaoyu Biswas Payal Owraghi Melissa Laura P. Zanello 《The Journal of steroid biochemistry and molecular biology》2007,103(3-5):457
1α,25(OH)2-vitamin D3 (1,25D) is considered a bone anabolic hormone. 1,25D actions leading to bone formation involve gene transactivation, on one hand, and modulation of cytoplasmic signaling, on the other. In both cases, a functional vitamin D receptor (VDR) appears to be required. Here we study 1,25D-stimulated calcium signaling that initiates at the cell membrane and leads to exocytosis of bone materials and increased osteoblast survival. We found that rapid 1,25D-induction of exocytosis couples to cytoplasmic calcium increase in osteoblastic ROS 17/2.8 cells. In addition, we found that elevation of cytoplasmic calcium concentration is involved in 1,25D anti-apoptotic effects via Akt activation in ROS 17/2.8 cells and non-osteoblastic CV-1 cells. In both cases, 1,25D-stimulated elevation of intracellular calcium is due in part to activation of L-type Ca2+ channels. We conclude that 1,25D bone anabolic effects that involve increased intracellular Ca2+ concentration in osteoblasts can be explained at two levels. At the single-cell level, 1,25D promotes Ca2+-dependent exocytotic activities. At the tissue level, 1,25D protects osteoblasts from apoptosis via a Ca2+-dependent Akt pathway. Our studies contribute to the understanding of the molecular basis of bone diseases characterized by decreased bone formation and mineralization. 相似文献
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New mixed metal complexes SrCu2(O2CR)3(bdmap)3 (R = CF3 (1a), CH3 (1b)) and a new dinuclear bismuth complex Bi2(O2CCH3)4(bdmap)2(H2O) (2) have been synthesized. Their crystal structures have been determined by single-crystal X-ray diffraction analyses. Thermal decomposition behaviors of these complexes have been examined by TGA and X-ray powder diffraction analyses. While compound 1a decomposes to SrF2 and CuO at about 380°C, compound 1b decomposes to the corresponding oxides above 800°C. Compound 2 decomposes cleanly to Bi2O3 at 330°C. The magnetism of 1a was examined by the measurement of susceptibility from 5–300 K. Theoretical fitting for the susceptibility data revealed that 1a is an antiferromagnetically coupled system with g = 2.012(7), −2J = 34.0(8) cm−1. Crystal data for 1a: C27H51N6O9F9Cu2Sr/THF, monoclinic space group P21/m, A = 10.708(6), B = 15.20(1), C = 15.404(7) Å, β = 107.94(4)°, V = 2386(2) Å3, Z = 2; for 1b: C27H60N6O9Cu2Sr/THF, orthorhombic space group Pbcn, A = 19.164(9), B = 26.829(8), C = 17.240(9) Å, V = 8864(5) Å3, Z = 8; for 2: C22H48O11N4Bi2, monoclinic space group P21/c, A = 17.614(9), B = 10.741(3), C = 18.910(7) Å, β = 109.99(3)°, V = 3362(2) Å3, Z = 4. 相似文献
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Zvi Schwartz Bryan F. Bell Liping Wang Ge Zhao Rene Olivares-Navarrete Barbara D. Boyan 《The Journal of steroid biochemistry and molecular biology》2007,103(3-5):606
Surface micron-scale and submicron scale features increase osteoblast differentiation and enhance responses of osteoblasts to 1,25-dihydroxyvitamin D3 [1α,25(OH)2D3]. β1 integrin expression is increased in osteoblasts grown on Ti substrates with rough microarchitecture, and it is regulated by 1α,25(OH)2D3 in a surface-dependent manner. To determine if β1 has a role in mediating osteoblast response, we silenced β1 expression in MG63 human osteoblast-like cells using small interfering RNA (siRNA). In addition, MG63 cells were treated with two different monoclonal antibodies to human β1 to block ligand binding. β1-silenced MG63 cells grown on a tissue culture plastic had reduced alkaline phosphatase activity and levels of osteocalcin, transforming growth factor β1, prostaglandin E2, and osteoprotegerin in comparison with control cells. Moreover, β1-silencing inhibited the effects of surface roughness on these parameters and partially inhibited effects of 1α,25(OH)2D3. Anti β1 antibodies decreased alkaline phosphatase but increase osteocalcin; effects of 1α,25(OH)2D3 on cell number and alkaline phosphatase were reduced and effects on osteocalcin were increased. These findings indicate that β1 plays a major and complex role in osteoblastic differentiation modulated by either surface microarchitecture or 1α,25(OH)2D3. The results also show that β1 mediates, in part, the synergistic effects of surface roughness and 1α,25(OH)2D3. 相似文献
20.
Lei Yang 《Inorganica chimica acta》2005,358(15):4505-4510
An organically templated zinc-substituted gallium phosphite, [H3N(CH2)2NH3]1/2 · [GaZn(HPO3)3(H2O)2] was synthesized under mild hydrothermal conditions in the presence of ethylenediamine (en) as structure-directing agent and characterized by single-crystal X-ray diffraction analysis. It crystallizes in the orthorhombic space group Pbcn with unit cell parameters: a = 18.6146(10) Å, b = 11.0454(6) Å, c = 10.9074(4) Å, V = 2242.62(19) Å3 and Z = 8. This compound has a three-dimensional framework built up from secondary building units (SBU) of Ga(III) (or Zn(II)) and HPO3 pseudopyramid by sharing vertices. The structure displays a two-dimensional channel system running along the [0 0 1] and [0 1 0] direction with 5-, 8- and 10-membered rings. The diprotonated ethylenediamine template molecules are located in the channels. In this structure, some of the Ga(III) sites are occupied by Zn(II) atoms. The compound was also characterized by IR spectroscopy, inductively coupled plasma (ICP), X-ray photoelectron spectra (XPS), differential thermal and thermogravimetric analyses. 相似文献