bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Nature of the Spin‐State Variation of [FeII(BPMEN)(CH3CN)2](ClO4)2 in Solution
Authors: Bryliakov Konstantin P. , Duban Eduard A. , Talsi Evgenii P. 
Published: December 2004

AbstractThermally‐induced spin variation behavior of [FeII(BPMEN)(CH3CN)2](ClO4)2 in CD3CN solution [low spin (LS)−high spin (HS)] was investigated. Variable temperature solution magnetic susceptibility measurements gave ΔH°LS−HS = 39.7 ± 2.0 kJ·mol−1 and ΔS°LS−HS = 135 ± 9 J·mol−1 K−1 values. These values are too high for a pure spin transition and reflect a significant contribution of chemical processes to the spin transition, namely, the detected dissociation of one bound acetonitrile molecule. Thus, LS−HS conversion should be regarded as a chemical equilibrium overlapped with a thermal spin crossover. The thermodynamic parameters for the overall process estimated from the variation of the NMR shifts with temperature (ΔH° = 40 ± 3 kJ·mol−1, ΔS° = 137 ± 10 J·mol−1 K−1) are in perfect agreement with those obtained by magnetic susceptibility measurements. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Two Novel Inorganic‐Organic Hybrid Frameworks Based on InIII‐BTC and InIII‐BTEC
Authors: Lin Zheng‐Zhong , Jiang Fei‐Long , Chen Lian , Yuan Da‐Qiang , Zhou You‐Fu , Hong Mao‐Chun 
Published: December 2004

AbstractHydrothermal reactions of InCl3 with 1,3,5‐benzenetricarboxylic acid (H3BTC) or pyromellitic dianhydride produced [In2(BTC)2(H2O)2]n·2nH2O (1) and [In2(H2BTEC)2(OH)2]n·2nH2O (2), respectively (H4BTEC = 1,2,4,5‐benzenetetracarboxylic acid). The structure of 1 is a 2D double‐layer network, while that of 2 is a 3D framework constructed from chains of corner‐linked octahedra. Intense greenish‐blue emissions at 494 nm (λex = 325 nm) for 1 and 489 nm (λex = 337 nm) for 2 were observed in the solid state. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Ordered Meso‐ and Macroporous Binary and Mixed Metal Oxides
Authors: Carreon Moises A. , Guliants Vadim V. 
Published: December 2004

AbstractA critical review is provided of the principles guiding the synthesis of meso‐ and macroporous metal oxides on multiple length scales in the presence of surfactant mesophases and colloidal arrays of monodisperse spheres, and correlations between the synthesis conditions and the properties of the resulting meso‐ and macroporous oxides, such as thermal stability, pore structure, elemental and nanophase compositions of the inorganic wall, etc. The thermal stability of mesostructured metal‐oxide phases, in particular, is discussed in terms of charge‐matching at the organic–inorganic interface, the strength of interactions between inorganic species and surfactant headgroups, the flexibility of the M–O–M bond angles in the constituent metal oxides, the Tammann temperature of the metal oxide, and the occurrence of redox reactions in the metal‐oxide wall. The ordered meso‐ and macroporous transition‐metal‐oxide phases are highly promising for a range of potential applications in separations, chemical sensing, heterogeneous catalysis, microelectronics, and photonics as, respectively, insulating layers of low‐dielectric‐constant and photonic‐bandgap materials. Furthermore, the functionalization of the internal pore surfaces in these materials and deposition of functional nanoparticles within the pores offer numerous new possibilities for molecular engineering of catalytic and other advanced nanostructured materials displaying quantum‐confinement effects. The emerging catalytic applications of these novel metal‐oxide phases are discussed in particular detail. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Lithium Cyanocuprates: Structural Studies of a Phosphane Adduct of a “Lower‐Order” Lithium Cyanocuprate
Authors: Davies Robert P. , Hornauer Stefan 
Published: December 2004

AbstractAddition of PPh3 to the “lower‐order” cyanocuprate PhCuCNLi results in a significant increase in reactivity in 1,4‐Michael addition reactions. This is explained by a marked structural change in the cyanocuprate reagent, observed in both THF solution and the solid state, to give [Ph2Cu]− cuprate anions and a [Cu2Li4(CN)4(PPh3)4(THF)10]2+ dication. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Formation of Hexagonal Coordination Complexes
Authors: Schultheiss Nate , Ellsworth Joseph M. , Bosch Eric , Barnes Charles L. 
Published: December 2004

AbstractThe synthesis of the ligand 1,3‐bis(3′‐pyridylethynyl)benzene and the coordination complex formed with copper(II) acetate is described. The complex is hexagonal with two ligands bridged by paddlewheel‐shaped dimeric copper(II) acetate moieties. The complexes are packed in such a way that the benzene rings from two separate complexes penetrate into the central cavity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Anion‐Induced Motion in a Ferrocene Diamide
Authors: Heinze Katja , Schlenker Manuela 
Published: December 2004

AbstractAn unsymmetrical diferrocene diamide has been reacted with chloride ions. The anion splits the intramolecular hydrogen bond of the receptor and is coordinated simultaneously by both amide groups of the receptor via hydrogen bonds. Chloride coordination changes the relative angular position of the cyclopentadienyl rings and the potential of the ferrocene/ferricinium redox couple. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The composition of the leaf essential oil of Satureja punctata (Benth.) Briq. from Zimbabwe
Authors: Chagonda Lameck S. , Chalchat Jean‐Claude 
Published: December 2004

AbstractSatureja punctata (Benth.) Briq., family Lamiaceae, from Mrewa, Zimbabwe, was hydrodistilled and the essential oil produced in 0.9% v/w yield was analysed by GC and GC–MS. Neral (33.4%) and geranial (52.5%) were the major components. Copyright © 2004 John Wiley & Sons, Ltd.
Chemical constituents of the essential oil of Asarum forbesii Maxim (Aristolochiaceae)
Authors: Zhang Feng , Xu Qing , Fu Shaoping , Ma Xiaoqiong , Xiao Hongbin , Liang Xinmiao 
Published: December 2004

AbstractThe essential oils from the leaves and roots of Asarum forbesii Maxim (Aristolochiaceae) were obtained by hydrodistillation and analysed by GC and GC–MS; 20 and 17 constituents were identiﬁed from the leaf and root oils, respectively. Methylisoeugenol (33.3%) and α‐asarone (19.2%) were the main constituents in the leaf oil, while α‐asarone (58.8%) and methyleugenol (10.3%) were the major constituents in the root oil. Copyright © 2004 John Wiley & Sons, Ltd.
BiGlobal stability analysis of steady flow in constricted channel geometries
Authors: Pitt R. E. , Sherwin S. J. , Theofilis V. 
Published: December 2004

AbstractIn this paper we apply a BiGlobal stability analysis technique to measure the stability of two‐dimensional constricted channel flows to three‐dimensional perturbations. Critical Reynolds numbers and spanwise perturbation wavelengths are presented for three instabilities of steady flow in constricted channels. Copyright © 2004 John Wiley & Sons, Ltd.
Novel relationships of growth factors to the G1/S transition in cultured astrocytes from rat forebrain
Authors: Langan Thomas J. , Slater Mary C. , Kelly Kindra 
Published: December 2004

AbstractThe cell cycle encompasses the sequential events regulating cell division. In mammalian brain, initiation of astrocyte cycling is critical during development and injury. To investigate the timing of growth factor requirements as they commit to passing through the G1 phase, primary and secondary rat astrocytes were stimulated to enter the cycle after serum or growth factor deprivation. Bromodeoxyuridine immunofluorescence was used to monitor S phase nuclei after growth factor re‐addition (at time 0). Cycle kinetics were identical whether quiescent cultures were exposed to 10% (vol/vol) calf serum, or to a defined medium containing fibroblast growth factor, insulin, and epidermal growth factor. The control point in late G1 that represents commitment to achieving the G1/S transition was identified by cycloheximide (CHX, 0.1 μg/ml) addition. Sensitivity to cycle arrest by CHX disappeared at 9–10 h. In contrast, shift‐down to growth factor‐deficient medium arrested cell cycling virtually until G1/S (12 h). With selective exposure during late G1 (9–12 h), no single agent permitted cycle progression. However, any two agents enabled cycling, and complementary or synergistic effects were apparent. These requirements were identical in astroglia from newborn and long‐term cultures.Thus, temporal dissociation exists between the processes of escape from CHX sensitivity and from requirements for growth factors, two recognized hallmarks of commitment to cycle progression. Furthermore, simultaneous presence of at least two growth factors is necessary at or near G1/S. Both findings distinguish astrocytes from several other cell types. © 1994 Wiley‐Liss, Inc.
In vivo staining of oligodendroglia in the rabbit retina
Authors: Ehinger B. , Zucker C. L. , Bruun A. , Adolph A. 
Published: December 2004

AbstractWe have discovered that a strongly fluorescent dye, sulforhodamine 101, when injected intravitreally in vivo, very effectively stains a class of star‐shaped cells in the innermost layers of the rabbit retina. The cells were strictly confined to the region containing medullated fibers and emitted dichotomously branching processes that ended up running some distance along the myelinated fibers. In favorable cases they could be seen to ensheath the fibers in a tube‐like fashion. No other retinal cells were stained. Shortly (hours) after the injection, the stain appeared in the cell cytoplasm, but it later became progressively more localized to intracellular granules. Most of the dye had disappeared after 2 days.Oligodendrocytes and astrocytes are the only cells known to be confined to the region of the medullated fibers in the rabbit retina, and hence the sulforhodamine 101‐stained cells should be one of these two types. Sulforhodamine 101‐stained cells were indistin‐guishable from oligodendrocytes identified by 2′,3′‐cyclic nucleotide phosphodiesterase (CNP) immunohistochemistry, and sequential staining showed them to be the same. Sulforhodamine 101‐stained cells were microinjected with lucifer yellow after lightly fixing rabbit retinas with formaldehyde and were found to be indistinguishable from oligodendrocytes. Glial fibrillary acidic protein staining for astrocytes showed fiber bundles that to some extent were similar to the bundles stained by sulforhodamine 101, but at the level of individual fibers, it was impossible to establish any concordance. Sulforhodamine 101 thus appears to stain oligodendrocytes rather than astrocytes in the rabbit retina.A related dye, rhodamine 123, also stained rabbit oligodendrocytes, but with poor contrast because many other cells and structures were also stained. A number of related rhodamine dyes did not stain the rabbit oligodendrocytes.The staining procedure is simple, has wide tolerance margins, gives robust results, and is well suited for cell microinjections and similar experiments. © 1994 Wiley‐Liss, Inc.
Gonadal hormone regulation of glial fibrillary acidic protein immunoreactivity and glial ultrastructure in the rat neuroendocrine hypothalamus
Authors: Garcia‐Segura Luis Miguel , Luqín Sonia , Párducz Arpad , Naftolin Frederjck 
Published: December 2004

AbstractThe influence of gonadal steroids on the ultrastructure of glial cells and on the immunoreactivity for the specific astrocytic marker glial fibrillary acidic protein (GFAP) has been assessed in the neuroendocrine hypothalamus. The following parameters were analyzed in the arcuate nucleus of adult female rats: the number and the surface density of cells immunoreactive for GFAP, the number of glial profiles showing bundles of glial filaments, the size of the bundles of glial filaments, and the proportion of neuronal perikaryal membrane apposed by glial processes. These parameters were studied during the different phases of the estrous cycle, after ovariectomy, and after the administration of estradiol or progesterone to ovariectomized rats. No significant differences were detected in the number of GFAP‐immunoreactive cells among the different experimental groups. The surface density of GFAP‐immunoreactive material, the number of glial profiles in the neuropil, and the proportion of neuronal perikaryal membrane covered by glia were increased in the afternoon of proestrus and in the morning of estrus compared with other phases of the estrous cycle or to ovariectomized rats and showed a rapid (5 h) and reversible increase in ovariectomized rats injected with 17β estradiol, with a maximal effect by 24 h after the administration of the hormone. In contrast, the size of the bundles of glial filaments was decreased in the afternoon of proestrus, in the morning of estrus, and by the administration of estradiol to ovariectomized rats. The parameters studied were not affected by the administration of progesterone. However, progesterone (300 μg/rat) blocked the effects of 17β estradiol (1, 10, and 300 μg). The results suggest that glial cells may be actively involved in the modulation of neuroendocrine events by the hypothalamus. © 1994 Wiley‐Liss, Inc.
Regulation of C6 glioma cell steroidogenesis by adenosine 3′,5′‐cyclic monophosphate
Authors: Papadopoulos Vassilios , Guarneri Patrizia 
Published: December 2004

AbstractIncubation of C6 glioma cells in the presence of aminoglutethimide, an inhibitor of cholesterol metabolism, together with either adenosine 3′,5′‐cyclic monophosphate (cAMP) analogues or agents that increase cAMP synthesis, such as cholera toxin, forskolin, and isoproterenol, stimulated the rate of pregnenolone formation by their isolated mitochondria. This effect of cAMP was blocked by the antagonist (Rp)‐cAMPS. The incorporation rate of mevalonolactone into pregnenolone was also increased by the stimulation of adenylyl cyclase activity in intact C6 cells. It is concluded that cAMP stimulates glial cell steroidogenesis by increasing the movement of the substrate, cholesterol, to the mitochondria, where it will be metabolized to pregnenolone by the side chain cleavage cytochrome P450 enzyme. © 1994 Wiley‐Liss, Inc.
MAP kinase cascade in astrocytes
Authors: Tournier Cathy , Pomerance Martine , Gavaret Jean Michel , Pierre Michel 
Published: December 2004

AbstractWe have studied in cultured rat astroglial cells MAP kinases, known for their role in intracellular signal transduction. The MAP kinase activity was stimulated by growth factors (FGFb, FGFa, EGF, PDGF, and IGF1), by a phorbol ester (TPA) activating‐protein kinase C (PKC), by a neuropeptide (endothelin‐1), and by a neuromediator (carbachol). Astrocytes pretreated for 18 h with TPA were still stimulated by growth factors and endothelin, suggesting that down‐regulated isoforms of PKC are not involved in MAP kinase activation. In contrast, the small effect of carbachol was suppressed by TPA pretreatment. Astrocytes contained two proteins (p41 and p44) recognized by MAP kinase antibody. These proteins were phosphorylated on tyrosine residues in the cytosols of stimulated astrocytes.The kinetics of MAP kinase activation by FGFb and IGF1 were very different. FGFb promoted a rapid activation of MAP kinase (about 10 min) plus a prolonged phase that lasted at least 12 h. IGF1 produced only a rapid transient peak of activation at about 20 min. Hence, extracellular signals might generate different effects in astrocytes by differentially modulating the MAP kinase cascade.On a Mono Q column the growth factor‐stimulated MAP kinase activity was separated into two peaks containing p41 and p44. Stimulation of astrocytes altered the elution pattern of p44 as a result of its phosphorylation.An ATP‐dependent MAP kinase activator (MW = 40–45 kDa) was found in fractions of FGFb‐stimulated cells which were not retained on Mono Q column, indicating the existence of a MAP kinase kinase (MEK) in astrocytes. C‐Raf, identified in other cells as a MAP kinase kinase kinase, was also present in astrocytes.Thus astrocytes contain many components of the MAP kinase cascade activated by growth factors that may also be implicated in the action of neuropeptides and neuromediators. © 1994 Wiley‐Liss, Inc.
K+‐, hypoosmolarity‐, and NH4+‐induced taurine release from cultured rabbit Müller cells: Role of NA+ and CL− ions and relation to cell volume changes
Authors: Faff‐Michalak L. , Reichenbach A. , Dettmer D. , Kellner K. , Albrecht J. 
Published: December 2004

AbstractThe release of preloaded radiolabeled taurine (TAU) from cultured rabbit Müller cells [14–21 days in vitro (DIV)] was measured before and after treatment with the following stimuli: (1) isoosmotic 65 mM KCI; (2) a medium made hypoosmotic by uncompensated lowering of Na+ by 40–100 mM; and 3) NH4Cl ranging from 0.25 to 5 mM. The same stimuli were tested for their effect on the cell volume by the 3‐0‐methyl‐D‐glucose (OMG) uptake method of Kletzien et al. (Anal Biochem 68:537, 1975). Hypoosmotic media and 65 mM KCl stimulated TAU release, and the release was well correlated with the increase of cell volume. The stimulatory effect of 65 mM KCI was abolished by isotonic removal of Cl− or Na+, and omission of either ion markedly enhanced the basal release of TAU. The results are roughly consistent with the characteristics of the swelling‐induced TAU release reported for cultured astrocytes and neurons of various CNS regions, and also for freshly isolated, nondissociated retina. Taken together, the results are indicative of a significant role of TAU release from Müller cells, in the osmosensory response of the retina.Ammonium chloride stimulated TAU release in a dose‐dependent manner, a significant stimulation being already observed at 0.5 mM, a concentration that is frequently measured in brain during acute hyperammonemia. The effect of NH4Cl was strictly chloride dependent at 0.5–2 mM, but partly Cl− independent at 5mM. The Kletzien's method did not appear to be well suited for measuring cell volume in the presence of ammonium ions. However, data from the literature on other CNS cell types plus our preliminary electron microscopic observations suggest that short‐term treatments with NH4Cl at concentrations up to 1 mM are unlikely to produce cell swelling. An alternative way in which ammonium ions might trigger the “tension sensor” for TAU release is discussed. We propose that in vivo, the outward‐driven TAU could counteract ammoniainduced neuronal disinhibition, according to a putative role for TAU as a gliotransmitter. © 1994 Wiley‐Liss, Inc.
Serum activity induces Schwann cell proliferation in vitro
Authors: Maertens Steven R. 
Published: December 2004

AbstractThe present series of experiments demonstrate that a polypeptide activity present in rat serum induces a proliferative response in cultured rat Schwann cells. Schwann cells in multi‐well tissue culture plates were incubated in medium containing 10% heat‐inactivated fetal bovine serum and serial dilutions of normal rat serum, and control preparations were incubated in the same culture medium without rat serum. Rates of cell proliferation were assayed by measuring DNA incorporation of tritiated thymidine using liquid scintillation counting. A prominent dose‐dependent proliferative response was observed among Schwann cells incubated with rat serum and rat plasma dilutions as compared to controls; this activity is abolished by heat inactivation and by proteolytic digestion, and was not affected by dialysis against a cellulose ester membrane that excludes molecules larger than 10,000 daltons. In contrast, no increase in DNA uptake of tritiated thymidine was observed when astrocyte and oligodendrocyte cultures were incubated with serial dilutions of rat serum. No proliferative effect was observed when rat Schwann cells were incubated with a dilution of standard adult bovine serum. These results suggest there is an intravascular plasma polypeptide with a molecular weight greater than 10,000 daltons that specifically stimulates Schwann cell proliferation, and it is proposed that this factor may be the mitogen responsible for the Schwann cell proliferative response known to occur after nerve injury. © 1994 Wiley‐Liss, Inc.
Contact with myelin evokes a release of calcium from internal stores in neonatal rat oligodendrocytes in vitro
Authors: Moorman Stephen J. , Hume Richard I. 
Published: December 2004

AbstractThe response of neonatal rat oligodendrocytes to contact with myelin extracts prepared from the central and peripheral nervous system was examined. Contact with either CNS myelin or PNS myelin resulted in collapse of the fine structure of the leading edge of oligodendrocytes in vitro. The collapse of the fine structure of oligodendrocyte processes was preceded by a substantial (approximately fivefold) increase in intracellular free calcium concentration. The calcium concentration increase was due, at least in part, to a release of calcium from internal stores, since it persisted when extracellular calcium was removed by chelation with EGTA. The increase in calcium concentration and the coincident morphological change suggest that oligodendrocytes might be able to recognize and react to specific molecules on the surface of other oligodendrocytes. © 1994 Wiley‐Liss, Inc.
Role of cytokines in lipopolysaccharide‐induced functional and structural abnormalities of astrocytes
Authors: Hu Shuxian , Martella Alice , Anderson W. Robert , Chao Chun C. 
Published: December 2004

AbstractThe mechanism underlying meningitis‐associated brain injury is unclear. This study investigated the hypothesis that lipopolysaccharide (LPS) alters astrocyte function and structure via the release of proinflammatory cytokines. In enriched murine astrocyte cultures, LPS inhibited (P < 0.05) glutamine synthetase activity, 3H‐gamma aminobutyric acid uptake, and DNA synthesis; LPS also induced ultrastructural changes. Antibodies to tumor necrosis factor‐α, interleukin‐1, and interleukin‐6 blocked (P < 0.05) in part the LPS‐induced inhibition of astrocyte function. Also, treatment of astrocyte cultures with cytokines significantly altered these astrocyte functions and ultrastructure. Taken together, the present findings support the hypothesis that LPS affects astrocyte function and structure via the release of proinflammatory cytokines, especially tumor necrosis factor‐α. © 1994 Wiley‐Liss, Inc.