bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spinal cord injury is accompanied by chronic progressive demyelination
Authors: Totoiu Minodora O. , Keirstead Hans S. 
Published: April 2005

AbstractPreceding the development of therapeutic strategies for spinal cord injury is an identification of those pathological processes that might serve as therapeutic targets. Although demyelination has been documented as a secondary degenerative component of spinal cord injury in several species including humans, the extent of demyelination and its functional consequence remain unknown. In this report, we document the extent of demyelination and remyelination up to 450 days following contusive spinal cord injury in adult rats. The overall number of demyelinated axons peaked at 1 day post injury, declined by 7–14 days post injury, and then progressively increased up to 450 days post injury. Oligodendrocyte and Schwann cell remyelinated axons appeared by 14 days post injury. Although remyelinated axons were present from 14 to 450 days post injury, remyelination was incomplete, as indicated by the presence of demyelinated axons at every time point examined. These studies demonstrate for the first time that spinal cord injury is accompanied by chronic progressive demyelination, and they substantiate demyelination as a target for therapeutic intervention. J. Comp. Neurol. 486:373–383, 2005. © 2005 Wiley‐Liss, Inc.
1,1'‐Bis(oxazolin‐2‐yl)ferrocenes: An Investigation of Their Complexation Behavior toward [Pd(η3‐allyl)Cl]2
Authors: Hartinger Christian G. , Nazarov Alexey A. , Arion Vladimir B. , Giester Gerald , Kuznetsov Maxim L. , Galanski Mathea Sophia , Keppler Bernhard K. 
Published: April 2005

AbstractThe coordination behavior of several aryl‐ and alkyl‐bis(oxazolinyl)ferrocenes, which were prepared in high yields from ferrocene‐1,1'‐dicarbonyl dichloride and enantiomerically pure or racemic amino alcohols via the corresponding bis(β‐hydroxyamide)s and dimesylates or ditosylates as intermediates, toward [Pd(η3‐allyl)Cl]2 was investigated by ESI mass spectrometry. The synthesized compounds were characterized by NMR spectroscopy and elemental analysis and the molecular structures of 1,1'‐bis[(R)‐4‐isopropyloxazolin‐2‐yl]ferrocene (6b), 1,1'‐bis[(S)‐4‐isopropyloxazolin‐2‐yl]ferrocene (7b), 1,1'‐bis[(S)‐4‐sec‐butyloxazolin‐2‐yl]ferrocene (11b), 1,1'‐bis[(S)‐4‐tert‐butyloxazolin‐2‐yl]ferrocene (12b), 1,1'‐bis[(R)‐4‐phenyloxazolin‐2‐yl]ferrocene (13b), and 1,1'‐bis[(S)‐4‐phenyloxazolin‐2‐yl]ferrocene (14b) were determined by single‐crystal X‐ray diffraction analysis. The coordination behavior studies by ESI‐MS show a strong preference for monodentate complex formation. This result is supported by theoretical studies carried out at the B3LYP level of theory. It was found that the latter coordination type of 1,1'‐bis[(S)‐4‐methyloxazolin‐2‐yl]ferrocene (1b) to an allylpalladium moiety is kinetically favored over the bidentate one. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Kinetic and Thermodynamic Studies of the Disproportionation of Hydrogen Peroxide by Dimanganese(ii,ii) and ‐(ii,iii) Complexes of a Bridging Phenolate Ligand
Authors: Dubois Lionel , Xiang Dao‐Feng , Tan Xiang‐Shi , Latour Jean‐Marc 
Published: April 2005

AbstractThe dimanganese(ii,ii) complexes [Mn2(L)(OAc)2(CH3OH)]‐(ClO4) (1a) and [Mn2(L)(OBz)2(H2O)](ClO4) (1b) as well as the dimanganese(ii,iii) complex [Mn2(L)(OAc)2(CH3OH)]‐(ClO4)2 (2a), where HL is the asymmetric phenol ligand2‐[bis(2‐pyridylmethyl)aminomethyl]‐6‐{[(benzyl)(2‐pyridyl‐methyl)amino]methyl}‐4‐methylphenol, react with hydrogen peroxide in acetonitrile solution. The initial reaction rates and their temperature and acid/base dependencies were investigated by monitoring the dioxygen evolution. These studies revealed a first‐order dependence on both the catalyst and H2O2 and a strong influence of the carboxylate. Electrospray ionisation mass spectrometry as well as EPR and UV/Vis spectroscopy were used to monitor the reaction catalysed by 2a. The same bis(μ‐oxo)dimanganese(III,IV) and (μ‐oxo)dimanganese(ii,iii) active species as found for 1a were detected in the catalytic medium. The EPR spectra recorded during the catalase‐like reaction revealed the accumulation of the magnetically uncoupled dimanganese(ii,iii) precursor of the active bis(μ‐oxo)dimanganese(III,IV) species which dominates the spectra in the case of 1a. This difference can be attributed to the different pH conditions generated by the reaction and reflects differences in the initiation phases for the two catalysts. Overall, the kinetic and thermodynamic studies of H2O2 disproportionation by these dimanganese complexes are fully consistent with the mechanism deduced from our previous extensive spectroscopic studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
CuI and CuII Complexes Containing Nitrite and Tridentate Aromatic Amine Ligand as Models for the Substrate‐Binding Type‐2 Cu Site of Nitrite Reductase
Authors: Yokoyama Hiroshi , Yamaguchi Kazuya , Sugimoto Manabu , Suzuki Shinnichiro 
Published: April 2005

AbstractCuI and CuII complexes containing a tridentate aromatic amine compound [bis(6‐methyl‐2‐pyridylmethyl)amine, Me2bpa] in the absence and presence of nitrite have been prepared as models for the active site of dissimilatory copper‐containing nitrite reductase (CuNIR). [CuII(Me2bpa)(H2O)(ClO4)]ClO4 (1), [CuII(Me2bpa)(NO2)(ClO4)] (2), [CuI(Me2‐bpa)(CH3CN)]PF6 (3) and [CuI(Me2bpa)(NO2)]2·[(Ph3P)2‐NPF6] (4) were prepared. The X‐ray crystal structural analyses of 1, 2, and 4 reveal that the geometries of the Cu centers are distorted square pyramidal, distorted octahedral, and tetrahedral, respectively. The coordination modes of the nitrite ligands in 2 and 4 depend on the oxidation state of the copper ion: nitrite is coordinated to CuII and CuI through two oxygen atoms (O,O'‐coordination mode) and one nitrogen atom (N‐coordination mode), respectively. A comparison of the absorption spectra of 1 and 2 in acetone solution indicates that the 387‐nm absorption band (ϵ = 780 M–1 cm–1) of 2 is a charge‐transfer transition. The broad absorption band at around 320 nm (ϵ ≈ 5000 M–1 cm–1) of 4 in dichloromethane is also due to a charge‐transfer transition. Functional modeling of CuNIR has been accomplished by treating solutions of 4 with acid; the nitrite‐binding CuI complex quantitatively gives the one‐electron reduction product,NO. The nitrite reduction of 4 in dichloromethane obeys a second‐order rate law, suggesting that the rate‐determining step would be protonation of the nitrite ligand of 4. Electronic structure calculations of the CuI and CuII complexes containing Me2bpa and nitrite by the density functional theory method demonstrate that the net charge of nitrite in CuI(Me2bpa)(nitro) is larger than that in CuI(Me2bpa)(nitrito). The mechanism of the nitrite reduction is discussed in comparison with the enzyme reaction mechanism of CuNIR. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Two New Diphenoxo‐Bridged Discrete Dinuclear CuIIGdIII Compounds with Cyclic Diimino Moieties: Syntheses, Structures, and Magnetic Properties
Authors: Koner Rajesh , Lee Gene‐Hsiang , Wang Yu , Wei Ho‐Hsiang , Mohanta Sasankasekhar 
Published: April 2005

AbstractTwo Schiff base compartmental ligands, H2L1 and H2L2, derived from the condensation of 3‐ethoxysalicylaldehyde with 1,2‐diaminocyclohexane and orthophenylenediamine, respectively, have been utilized to isolate two diphenoxo‐bridged discrete dinuclear CuIIGdIII complexes, [CuII(H2O)L1GdIII(NO3)3] (3) and [CuIIL2GdIII(NO3)3] (4). This is the first report on the 3d‐4f compounds derived from compartmental Schiff base ligands with cyclic diamines. The compounds 3 and 4 crystallize in the triclinic P and orthorhombic Pna2(1) space groups, respectively, with the following unit cell parameters – 3: a = 8.8713(2) Å, b = 12.8399(3) Å, c = 14.0067(3) Å, α = 80.6649(5)°, β = 77.4059(5)°, γ = 76.8879(5)°, and Z = 2; 4: a = 9.2210(1) Å, b = 16.5407(2) Å, c = 19.9248(4) Å, and Z = 4. Structural analysis reveals that both are discrete dinuclear complexes. In 3, one water molecule is coordinated to the copper(II) ion to result in a square‐pyramidal coordination geometry, while the geometry of the coppe(II) center in 4 is square planar. In both complexes, the gadolinium(III) center has an O10 coordination environment. In contrast to expectation, although the N2O2 cavity affords a better planar environment for the copper(II) center in 4, the bridging moiety in complex 3 is more planar than that in 4 or in most of the previously reported examples (the dihedral angle between two CuO2Gd planes: 2.1° for 3 and 7.1° for 4). Variable‐temperature and variable‐field magnetic measurements reveal that the metal centers in both the complexes are ferromagnetically coupled (J values: 6.3 cm–1 for 3 and 5.4 cm–1 for 4; H = –2JSCu·SGd). Interestingly, complex 3 exhibits strongest ferromagnetic interaction among the related compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis of Palladium(II) and Platinum(II) Complexes with Crown Ether Phosphane Ligands: Stille Coupling of Aryl Iodides in Water
Authors: Fresneda Jorge , de Jesús Ernesto , Gómez‐Sal Pilar , López Mardomingo Carmen 
Published: April 2005

AbstractThe crown ether phosphanes PAr*Ph2(1) and PAr*2R [Ar* = 3,4‐(18‐crown‐6)‐phenyl; R = Me (2); R = Ph (3)], prepared from PCl2R and Ar*Li, have been studied. The syntheses and characterization of their oxides (4–6), and their BH3(7–9), PdCl2(10–12), and PtCl2(13–15) complexes are reported. The molecular structure of the borane complex PAr*2Ph·BH3(9) has been determined by X‐ray structural analysis. Spectroscopic data suggest that phosphanes1–3have similar electronic properties and steric requirements to the corresponding phenylphosphane ligands PPh2Me and PPh3. Crown ether methylphosphane2and its complexes are remarkably water soluble, but1and3are only slightly soluble. Palladium(II) complexes14and15have been tested as catalysts in the Stille coupling of phenyltrichlorostannanes and aryl iodides in water. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Dinuclear Copper(II) Complexes of Two Homologous Pyrazine‐Based Bis(terdentate) Diamide Ligands
Authors: Klingele (née Hausmann) Julia , Moubaraki Boujemaa , Murray Keith S. , Boas John F. , Brooker Sally 
Published: April 2005

AbstractThe 1:1 reactions of the new bis(terdentate) diamide ligandN,N'‐bis(2‐pyridylmethyl)pyrazine‐2,5‐dicarboxamide(H2L1) and its higher homologue N,N'‐bis[2‐(2‐pyridyl)ethyl]pyrazine‐2,5‐dicarboxamide (H2L2) with Cu(BF4)2·4 H2O in the absence of added base have consistently afforded dicopper(II) complexes of the doubly deprotonated ligands (L1)2– and (L2)2–. The complex [CuII2(L2)(H2O)2(MeCN)2](BF4)2 (2a) has been structurally characterised. Subsequently, reactions employing a correct stoichiometric 2:1 metal‐to‐ligand ratio in MeCN have afforded bulk samples of the dinuclear complexes. The compounds [CuII2(L1)(MeCN)2(H2O)2](BF4)2·H2O (1a·H2O) and [CuII2(L2)(H2O)4(BF4)2]·2 H2O (2b·2 H2O) have been structurally characterised. While complex 1a·H2O of the lower ligand homologue exhibits very weak antiferromagnetic spin coupling (J = –0.24 cm–1), complex 2b of the higher ligand homologue exhibits very weak ferromagnetic spin coupling (J = +0.67 cm–1). EPR studies have been carried out on polycrystalline powders and frozen DMF solutions of 1a·H2O and 2b·2 H2O. The EPR spectra of the polycrystalline powders indicate the presence of dipolar broadening and weak intermolecular exchange, while those of the frozen DMF solutions are characteristic of dipolar‐coupled CuII pairs within the dinuclear molecules, with no evidence of intra‐ or intermolecular exchange. The spectral simulations confirm that the binuclear structure and the Cu···Cu distances are retained in frozen solution. Dinuclear SiF62– containing compounds, [CuII2(L1)(H2O)4](SiF6) (1b) and {[CuII2(L1)(H2O)2(μ‐SiF6)]·4 H2O}∞ (1c·4 H2O), were obtained serendipitously, in nearly quantitative yield, by the 2:1 reaction of Cu(BF4)2·4 H2O with H2L1 in H2O. The unexpected SiF62– anions were generated in the course of the reaction by partial hydrolysis of the BF4– anions employed, thus forming traces of HF which reacted with the glassware. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
One‐Dimensional Chains Formed by First‐Row Transition Metal(II) Nitrates and Pyrimidine – Influence of Water Coordination on Structural Reliability
Authors: Barnett Sarah A. , Champness Neil R. , Wilson Claire 
Published: April 2005

AbstractAn isostructural family of one‐dimensional coordination polymers, [M(NO3)2(pym)(H2O)2]∞ [M = Mn (1), Co (2), Ni (3), Zn (4); pym = pyrimidine], has been prepared and their phase purity assessed. It is shown that in contrast to otherM(NO3)2–pyrimidine coordination polymers, 1–4 show a surprising preference for the structure reported herein rather the wide variety of other possible product architectures. It is also shown that a related complex [Ni(NO3)2(pym)(MeCN)2]∞ (5), in which water ligands observed in 1–4 are replaced by MeCN molecules, can also be prepared. However, 5 is highly hygroscopic and readily converts to 3 in the presence of atmospheric water. The implication of the uniformity of structure is discussed in relation to the serendipitous coordination of water molecules to the metal centres. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Use of spatial factors in the analysis of heavy metals in sediments in a Brazilian coastal region
Authors: Bailey T. C. , Barcellos C. , Krzanowski W. J. 
Published: April 2005

AbstractEnvironmental phenomena often generate complex data which are not only multivariate, but where spatial structure and dependency may also be important. One potential area of interest is that of identifying combinations of variables which exhibit distinctive spatial structure in a set of multivariate and geographically indexed observations, e.g. long, as opposed to short, range spatial contiguity. Such components may serve not only to characterize the main determinants in the geographical distribution of a set of environmental measurements, but may also provide useful insight into the physical or environmental processes underlying and governing that distribution. This article suggests one form of multivariate technique which may be useful in such a context. We demonstrate the method in relation to data comprising measures of various heavy metals in sediments in a Brazilian coastal region. Copyright © 2005 John Wiley & Sons, Ltd.
Mapping sea bird densities over the North Sea: spatially aggregated estimates and temporal changes
Authors: Pebesma Edzer J. , Duin Richard N. M. , Burrough Peter A. 
Published: April 2005

AbstractIn the Dutch sector of the North Sea, sea bird densities are recorded bi‐monthly by using airborne strip‐transect monitoring. From these data we try to estimate: (i) high‐resolution spatial patterns of sea bird densities; (ii) low‐resolution spatial‐average bird densities for large areas; and (iii) temporal changes in (i) and (ii), using data on Fulmaris glacialis as an example. For spatial estimation, we combined Poisson regression for modelling the trend as a function of water depth and distance to coast with kriging interpolation of the residual variability, assuming spatial (co)variances to be proportional to the trend value. Spatial averages were estimated by block kriging. For estimating temporal differences we used residual cokriging for two consecutive years, and show how this can be extended to analyse trends over multiple years. Approximate standard errors are obtained for all estimates. A comparison with a residual simple kriging approach reveals that ignoring temporal cross‐correlations leads to a severe loss of statistical accuracy when assessing the significance of temporal changes.This article shows results for Fulmaris glacialis monitored during August/September in 1998 and 1999. Copyright © 2005 John Wiley & Sons, Ltd.
An improved formula obtained by simulated annealing for the computation of maximum SINR for DS‐CDMA receiver with exponentially weighted despreading function
Authors: Ciftlikli Cebrail , Kalinli Adem , Develi Ibrahim 
Published: April 2005

AbstractIt is well known that direct sequence‐code division multiple access (DS‐CDMA) receiver using exponentially weighted despreading function outperforms significantly receiver using rectangular despreading function. The maximum value of the signal‐to‐interference‐plus‐noise ratio (SINR) for this type of receiver is an important indicator to evaluate the bit error rate (BER) performance of the system. In this paper, we propose an improved formula obtained by using simulated annealing (SA) algorithm to calculate the maximum value of the SINR. It is shown that the results computed by the proposed formula are more accurate than the results obtained by the simplified formula available in the literature. Copyright © 2005 AEIT.
Assessment by M‐FISH of karyotypic complexity and cytogenetic evolution in bladder cancer in vitro
Authors: Williams Sarah V. , Adams Jacqui , Coulter Jane , Summersgill Brenda M. , Shipley Janet , Knowles Margaret A. 
Published: April 2005

AbstractWe carried out multiplex fluorescence in situ hybridization (M‐FISH) and follow‐up FISH studies on a large series of transitional cell carcinoma (TCC) cell lines and 2 normal urothelium–derived cell lines, several of which have not had karyotypes reported previously. M‐FISH analysis, with appropriate follow‐up, complements conventional cytogenetic analysis and array CGH studies, allowing a more accurate definition of karyotype. The detailed karyotypic data obtained will assist in choosing suitable cell lines for functional studies and identifies common losses, gains, breakpoints and potential fusion gene sites in TCC. We have shown changes in cell lines RT112 and DSH1 following prolonged culture, and differences in karyotype, between RT112 cultures obtained from different sources. We propose a model for the evolutionary changes leading to these differences. A comparison with the literature found other examples of differences in cell‐line karyotypes between different sources. Nevertheless, several karyotypic changes were preserved between different sources of the same cell line and were also seen in more than one cell line. These may be the most important changes and include −8p, +20, 4q−, 10p−, 16p− and breaks in 8p21. We carried out a more detailed follow‐up of some regions, which showed involvement of 8p breaks and losses in 15 of 16 TCC cell lines but in neither of the normal urothelium–derived cell lines. Some changes represented distal loss, whereas others were small deletions. Further study of this region is warranted. Supplementary material for this article can be found on the Genes, Chromosomes and Cancer website at http://www.interscience.wiley.com/jpages/1045‐2257/suppmat/index.html. © 2005 Wiley‐Liss, Inc.
Acute myeloid leukemia with a complex aberrant karyotype is a distinct biological entity characterized by genomic imbalances and a specific gene expression profile
Authors: Schoch Claudia , Kern Wolfgang , Kohlmann Alexander , Hiddemann Wolfgang , Schnittger Susanne , Haferlach Torsten 
Published: April 2005

AbstractAcute myeloid leukemia (AML) with a complex aberrant karyotype is a distinct biological entity. It is characterized by: (1) a sharp increase in incidence above age 50; (2) a characteristic pattern of chromosomal gain and, especially, loss, that is, of 5q14q33, 7q32q35, and 17p13, translating into reduced expression of genes in these regions; (3) a unique gene expression pattern including up‐regulation of genes involved in DNA repair; (4) a high incidence of TP53 deletions and/or mutations; and (5) an overall unfavorable prognosis. Further unraveling the biology of AML with a complex aberrant karyotype by gene expression profiling may provide deeper insights into the pathogenesis of as well as the reasons for chemoresistance in this AML subtype. These data may be the basis for developing targeted therapeutic strategies to increase the cure rate in patients with AML and a complex aberrant karyotype. © 2005 Wiley‐Liss, Inc.
Failure and function of intracellular pH regulation in acute hypoxic‐ischemic injury of astrocytes
Authors: Chesler Mitchell 
Published: April 2005

AbstractAstrocytes can die rapidly following ischemic and traumatic injury to the CNS. Brain acid–base status has featured prominently in theories of acute astrocyte injury. Failure of astrocyte pH regulation can lead to cell loss under conditions of severe acidosis. By contrast, the function of astrocyte pH regulatory mechanisms appears to be necessary for acute cell death following the simulation of transient ischemia and reperfusion. Severe lactic acidosis, and the failure of astrocytes to regulate intracellular pH (pHi) have been emphasized in brain ischemia under hyperglycemic conditions. Direct measurements of astrocyte pHi after cardiac arrest demonstrated a mean pHi of 5.3 in hyperglycemic rats. In addition, both in vivo and in vitro studies of astrocytes have shown similar pH levels to be cytotoxic. Whereas astrocytes exposed to hypoxia alone may require 12–24 h to die, acidosis has been found to exacerbate and speed hypoxic loss of these cells. Recently, astrocyte cultures were exposed to hypoxic, acidic media in which the large ionic perturbations characteristic of brain ischemia were simulated. Upon return to normal saline (“reperfusion”), the majority of cells died. This injury was dependent on external Ca2+ and was prevented by inhibition of reversed Na+‐Ca2+ exchange, blockade of Na+‐H+ exchange, or by low pH of the reperfusion saline. These data suggested that cytotoxic elevation of [Ca2+]i occurred during reperfusion due to a sequence of activated Na+‐H+ exchange, cytosolic Na+ loading, and resultant reversal of Na+‐Ca2+ exchange. The significance of this reperfusion model to ischemic astrocyte injury in vivo is discussed. © 2005 Wiley‐Liss, Inc.
Potassium homeostasis in the ischemic brain
Authors: Leis Jerome A. , Bekar Lane K. , Walz Wolfgang 
Published: April 2005

AbstractExtracellular [K+] can range within 2.5–3.5 mM under normal conditions to 50–80 mM under ischemic and spreading depression events. Sustained exposure to elevated [K+]o has been shown to cause significant neuronal death even under conditions of abundant glucose supply. Astrocytes are well equipped to buffer this initial insult of elevated [K] through extensive gap junctional coupling, Na+/K+ pump activity (with associated glycogen and glycolytic potential), and endfoot siphoning capability. Their abundant energy availability and alkalinizing mechanisms help sustain Na+/K+ ATPase activity under ischemic conditions. Furthermore, passive K+ uptake mechanisms and water flux mediated through aquaporin‐4 channels in endfoot processes are important energy‐independent mechanisms. Unfortunately, as the length of ischemic episode is prolonged, these mechanisms increase to a point where they begin to have repercussions on other important cellular functions. Alkalinizing mechanisms induce an elevation of [Na+]i, increasing the energy demand of Na+/K+ ATPase and leading to eventual detrimental reversal of the Na+/glutamate− cotransporter and excitotoxic damage. Prolonged ischemia also results in cell swelling and activates volume regulatory processes that release excessive excitatory amino acids, further exacerbating excitotoxic injury. In the days following ischemic injury, reactive astrocytes demonstrate increased cell size and process thickness, leading to improved spatial buffering capacity in regions outside the lesion core where there is better neuronal survival. There is a substantial heterogeneity among reactive astrocytes, with some close to the lesion showing decreased buffering capacity. However, it appears that both Na+/K+ ATPase activity (along with energy production processes) as well as passive K+ uptake mechanisms are upregulated in gliotic tissue outside the lesion to enhance the above‐mentioned homeostatic mechanisms. © 2005 Wiley‐Liss, Inc.