bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theory of chemical bonds in metalloenzymes. XVII. Symmetry breaking in manganese cluster structures and chameleonic mechanisms for the OO bond formation of water splitting reaction
Authors: Saito Toru , Shoji Mitsuo , Kanda Keita , Isobe Hiroshi , Yamanaka Shusuke , Kitagawa Yasutaka , Yamada Satoru , Kawakami Takashi , Okumura Mitsutaka , Yamaguchi Kizashi 
Published: September 2011

AbstractSymmetry breaking in cluster structures of manganese oxides by doping of Ca(II) ion is examined in relation to chameleonic mechanisms of water splitting reaction. The orbital and spin correlation diagrams have been depicted to clarify one‐electron transfer and electron‐pair transfer mechanisms for the reaction. The spin‐polarized molecular orbital models have been applied to elucidate correspondence between magnetic‐coupling mode and reaction mechanism of the oxygen–oxygen (OO) bond formation and oxygen evolution catalyzed by multicenter Ca(II) manganese oxides and related systems. The present UB3LYP calculations followed by the natural orbital analyses have been performed to elucidate electronic structures of the key intermediates and the transition state structure for the OO bond formation. The results indicate that the reaction proceeds through the continuous diradicaloid mechanism without discreet free radical fragments and/or electron‐pair transfer mechanism induced by symmetry breaking with Ca(II) in the pure low‐spin singlet state. The computational results are compatible with local singlet and triplet diradical‐coupling mechanisms for the OO bond formation in the low‐ and high‐spin states, respectively. Thus, magnetic (exchange) coupling modes in the oxygen evolution complex are directly related to the local singlet and triplet diradical mechanisms as in the case of soluble methane monooxygenase. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
A COMPARISON OF TWO ELECTROFISHING PROGRAMMES USED TO MONITOR FISH ON THE ILLINOIS RIVER, ILLINOIS, USA
Authors: McClelland M. A. , Irons K. S. , Sass G. G. , O'hara T. M. , Cook T. R. 
Published: September 2011

ABSTRACTThe Illinois River Biological Station monitors fish communities in the Illinois River using two different electrofishing programmes, one using three‐phase alternating current [AC; The Long Term Illinois Fish Population Monitoring Program or long‐term electrofishing (LTEF)] and the other pulsed direct current [DC; The Long Term Resource Monitoring Program (LTRMP)]. In 2001, we replicated three‐phase AC sampling sites with pulsed‐DC electrofishing gear to test for differences between the two collection methods and programmes. Electrofishing runs at each site were standardized by length and time, with 48 samples collected for each gear. Our objective was to test for differences in fish catch rates using total catch, species richness, fish size ranges, and sample composition and structure. Total catch was significantly greater for LTRMP electrofishing (4368 total fish, mean = 91.0 fish per sample) compared with LTEF electrofishing (1423 total fish, mean = 29.6 fish per sample). Species richness also was significantly greater for LTRMP electrofishing (50 total species, mean = 12.9 species per site) compared with LTEF electrofishing (38 total species, mean = 7.9 species per site). Size ranges of fishes, composed of 100‐mm‐length groups, showed higher total catches for the LTRMP within all length groups. Although our analyses suggest that collections from the LTRMP were significantly greater in most instances, a consistent pattern of species composition between the two programmes was not evident. Our results suggest that caution must be taken when attempting to compare fish community composition and structure information between these programmes. Copyright © 2011 John Wiley & Sons, Ltd.
SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN
Authors: Douglas Shields F. , Lizotte Richard E. , Knight Scott S. 
Published: September 2011

ABSTRACTThe floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L−1, the median total phosphorus was 0.29 mg L−1 and the median total nitrogen was 1.56 mg L−1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.
A mathematical theory of de‐integrating long‐time integrated rainfall and its application for predicting 1‐min rain rate statistics
Authors: Matricciani Emilio 
Published: September 2011

SUMMARYTo date, the methods devised for converting long‐term experimental probability distribution (pd), , of the rain rate ρT integrated in T min (T > > 1 min) to 1‐min pd, PR(R), of the instantaneous rain rate R, are based on flawed T‐min data and, as such, are not based on fully reliable first principles. is not only an upward translated version of PR(R) but also rotated clockwise and distorted. The current methods do not correct these errors. We propose and discuss a mathematical theory, which corrects these errors and thus de‐integrates T‐min experimental pds into the corresponding 1‐min pd, the input required by all rain attenuation prediction methods. The theory is based on simple first principles whose parameters are calibrated by means of a large and reliable rain‐rate data bank recorded in Spino d'Adda, a site held as an experimental laboratory and used for exploratory data analysis. We show that PR(R) is modelled by four distinct functions in four disjoint ranges, and that this modelling is physically meaningful. We have tested the theory up to integration times of 12 h, with a large experimental data bank of 1‐min rain‐rate time series recorded in Gera Lario, Fucino, Rome, Prague, and Montreal, besides Spino d'Adda. Defined the fraction of rainy time in an average year, Po (%), we have found that: (a) the modelling is very good up to 6 h; (b) in the range from about Po to 0.001%, the error values are constant, with average error set at about − 3% and RMS error less than 8% for T ≤ 120 min, less than about 9% for 120 < T ≤ 360 min. We have also applied the theory to rain‐rate time series provided by meteorological agencies with integration time T = 60 min (blind test) with excellent result. Copyright © 2011 John Wiley & Sons, Ltd.
Corporate capital allocation: a behavioral perspective
Authors: Bardolet David , Fox Craig R. , Lovallo Dan 
Published: September 2011

AbstractPrevious research on capital investment has identified a tendency in multibusiness firms toward cross‐subsidization from well‐performing to poorly performing divisions, a phenomenon that has previously been attributed to principal‐agent conflicts between headquarters and divisions (Stein,2003). In this paper, we argue that cross‐subsidization reflects a more general tendency toward even allocation over all divisions in multibusiness firms that is driven, at least in part, by the cognitive tendency to naïvely diversify when making investment decisions (Benartzi and Thaler,2001). We observe that this tendency also leads to partition dependence in which capital allocations vary systematically with the divisions and subdivisions into which the firm is organized or over which capital is allocated. Our first study uses archival data to show that firms' internal capital allocations are biased toward equality over the number of business units into which the firm is partitioned. Two further experimental studies of experienced managers examine whether this bias persists when participants are asked to allocate capital to various divisions of a hypothetical firm. This methodology eliminates the possibility of agency conflicts. Nevertheless, allocations varied systematically with the divisional and subdivisional structure of the firm and with a centralized or decentralized capital allocation manner. Copyright © 2011 John Wiley & Sons, Ltd.
Changes in Glycosphingolipid Composition During Differentiation of Human Embryonic Stem Cells to Ectodermal or Endodermal Lineages
Authors: Liang Yuh-Jin , Yang Bei-Chia , Chen Jin-Mei , Lin Yu-Hsing , Huang Chia-Lin , Cheng Yuan-Yuan , Hsu Chi-Yen , Khoo Kay-Hooi , Shen Chia-Ning , Yu John 
Published: September 2011

Abstract
Glycosphingolipids (GSLs) are ubiquitous components of cell membranes that can act as mediators of cell adhesion and signal transduction and can possibly be used as cell type-specific markers. Our previous study indicated that there was a striking switch in the core structures of GSLs during differentiation of human embryonic stem cells (hESCs) into embryoid body (EB), suggesting a close association of GSLs with cell differentiation. In this study, to further clarify if alterations in GSL patterns are correlated with lineage-specific differentiation of hESCs, we analyzed changes in GSLs as hESCs were differentiated into neural progenitors or endodermal cells by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) and tandem mass spectrometry (MS/MS) analyses. During hESC differentiation into neural progenitor cells, we found that the core structures of GSLs switched from globo- and lacto- to mostly ganglio-series dominated by GD3. On the other hand, when hESCs were differentiated into endodermal cells, patterns of GSLs totally differed from those observed in EB outgrowth and neural progenitors. The most prominent GSL identified by the MALDI-MS and MS/MS analysis was Gb4Ceramide, with no appreciable amount of stage-specific embryonic antigens 3 or 4, or GD3, in endodermal cells. These changes in GSL profiling were accompanied by alterations in the biosynthetic pathways of expressions of key glycosyltransferases. Our findings suggest that changes in GSLs are closely associated with lineage specificity and differentiation of hESCs.
Brief Report: L1 Cell Adhesion Molecule, a Novel Surface Molecule of Human Embryonic Stem cells, Is Essential for Self-Renewal and Pluripotency
Authors: Son Yeon Sung , Seong Rho Hyun , Ryu Chun Jeih , Cho Yee Sook , Bae Kwang-Hee , Chung Sang J. , Lee Bonghee , Min Jeong-Ki , Hong Hyo Jeong 
Published: September 2011

AbstractDespite the recent identification of surface markers of undifferentiated human embryonic stem cells (hESCs), the crucial cell-surface molecules that regulate the self-renewal capacity of hESCs remain largely undefined. Here, we generated monoclonal antibodies (MAbs) that specifically bind to undifferentiated hESCs but not to mouse embryonic stem cells. Among these antibodies, we selected a novel MAb, 4-63, and identified its target antigen as the L1 cell adhesion molecule (L1CAM) isoform 2. Notably, L1CAM expressed in hESCs lacked the neuron-specific YEGHH and RSLE peptides encoded by exons 2 and 27, respectively. L1CAM colocalized with hESC-specific cell-surface markers, and its expression was markedly downregulated on differentiation. Stable L1CAM depletion markedly decreased hESC proliferation, whereas L1CAM overexpression increased proliferation. In addition, the expression of octamer-binding transcription factor 4, Nanog, sex-determining region Y–box 2, and stage-specific embryonic antigen (SSEA)-3 was markedly downregulated, whereas lineage-specific markers and SSEA-1 were upregulated in L1CAM-depleted hESCs. Interestingly, the actions of L1CAM in regulating the proliferation and differentiation of hESCs were exerted predominantly through the fibroblast growth factor receptor 1 signaling pathway. Taken together, our results suggest that L1CAM is a novel cell-surface molecule that plays an important role in the maintenance of self-renewal and pluripotency in hESCs.
Cocaine induces the expression of MEF2C transcription factor in rat striatum through activation of SIK1 and phosphorylation of the histone deacetylase HDAC5
Authors: Dietrich Jean‐Bernard , Takemori Hiroshi , Grosch‐Dirrig Sylvie , Bertorello Alejandro , Zwiller Jean 
Published: September 2011

AbstractDistinct forms of MEF2 transcription factor act as positive or negative regulators of dendritic spine formation, with MEF2C playing a key regulator role in synapse plasticity. We report here that acute cocaine treatment of rats induced the expression of MEF2C in the striatum through a recently discovered transduction pathway. Repeated injections were found to induce MEF2C to a lesser extent. The mechanism by which MEF2C was induced involves the subsequent activation of the salt‐inducible kinase SIK1 and the phosphorylation of HDAC5, a member of the class IIa of HDACs. Cocaine activated SIK1 by phosphorylation on Thr‐182 residue, which was accompanied by the nuclear import of the kinase. In the nuclear compartment, SIK1 then phosphorylated HDAC5 causing the shuttling of its phospho‐form from the nucleus to the cytoplasm of striatal cells. Activation of SIK1 by cocaine was further validated by the phosphorylation of TORC1/3, which was followed by the shuttling of TORC proteins from the nucleus to the cytoplasm. Activation of MEF2C was assessed by measuring the expression of the MEF2C gene itself, since the gene is known to be under the control of its own product. Since MEF2C plays a key role in memory/learning processes, activation of this pathway by cocaine is probably involved in plasticity mechanisms whereby the drug establishes its long‐term effects such as drug dependence. Synapse, 2012. © 2011 Wiley Periodicals, Inc.
Running wheel exercise ameliorates methamphetamine‐induced damage to dopamine and serotonin terminals
Authors: O'dell Steven J. , Galvez Bryan A. , Ball Alexander J. , Marshall John F. 
Published: September 2011

AbstractRepeated administration of methamphetamine (mAMPH) to rodents in a single‐day “binge” produces long‐lasting damage to dopaminergic and serotonergic terminals. Because previous research has demonstrated that physical activity can ameliorate nigrostriatal injury, this study investigated whether voluntary exercise in rats can alter the monoaminergic damage resulting from a neurotoxic mAMPH binge. Adult male rats were allowed constant access to running wheels or kept in nonwheel cages for three weeks, then given a binge dosing regimen of mAMPH or saline. The rats were returned to their original environments for three additional weeks post‐mAMPH. [125I]RTI‐55 binding and autoradiography was used to quantify dopamine transporters (DAT), and radioimmunocytochemistry was used to quantify striatal tyrosine hydroxylase (TH). Binge mAMPH treatment significantly reduced striatal DAT and TH in a regionally specific pattern; with greatest effects in ventral caudate‐putamen (CP) and relative sparing of the nucleus accumbens septi (NAc). The effects of mAMPH on striatal DAT and TH were ameliorated in the running, compared to the sedentary, animals. Also, mAMPH was found to reduce [125I]RTI‐55 binding to serotonin transporters (SERT) in frontoparietal cortex, and this too was significantly attenuated by exercise. Additional correlational analyses showed that the post‐mAMPH running of individual animals predicted the amelioration of striatal DAT and TH as well as frontoparietal SERT. Overall, voluntary exercise significantly diminished mAMPH‐induced forebrain monoaminergic damage. The significant correlations between post‐mAMPH exercise and markers of monoaminergic terminal integrity provide novel evidence that voluntary exercise may exert beneficial effects on behavior in recovering mAMPH addicts. Synapse, 2012. © 2011 Wiley Periodicals, Inc.
Granulocyte colony stimulating factor neuroprotective effects on spinal motoneurons after ventral root avulsion
Authors: De freria Camila Marques , Barbizan Roberta , De Oliveira Alexandre Leite Rodrigues 
Published: September 2011

AbstractG‐CSF is a glycoprotein commonly used to treat neutropenia. Recent studies have shown that the G‐CSF receptor (G‐CSF‐R) is expressed by neurons in the central nervous system (CNS), and neuroprotective effects of G‐CSF have been observed. In this study, the influence of G‐CSF treatment on the glial reactivity and synaptic plasticity of spinal motoneurons in rats subjected to ventral root avulsion (VRA) was investigated. Lewis rats (7 weeks old) were subjected to unilateral VRA and divided into two groups: G‐CSF and placebo treated. The drug treated animals were injected subcutaneously with 200 μg/kg/day of G‐CSF for 5 days post lesion. The placebo group received saline buffer. After 2 weeks, both groups were sacrificed and their lumbar intumescences processed for transmission electron microscopy (TEM), motoneuron counting, and immunohistochemistry with antibodies against GFAP, Iba‐1, and synaptophysin. Furthermore, in vitro analysis was carried out, using newborn cortical derived astrocytes. The results indicated increased neuronal survival in the G‐CSF treated group coupled with synaptic preservation. TEM analyses revealed an improved preservation of the synaptic covering in treated animals. Additionally, the drug treated group showed an increase in astroglial reactivity both in vivo and in vitro. The astrocytes also presented an increased cell proliferation rate when compared with the controls after 3 days of culturing. In conclusion, the present results suggest that G‐CSF has an influence on the stability of presynaptic terminals in the spinal cord as well as on the astroglial reaction, indicating a possible neuroprotective action. Synapse, 2012. © 2011 Wiley Periodicals, Inc.
Next challenges in protein–protein docking: from proteome to interactome and beyond
Authors: Melquiond Adrien S.J. , Karaca Ezgi , Kastritis Panagiotis L. , Bonvin Alexandre M.J.J. 
Published: September 2011

AbstractAdvances in biophysics and biochemistry have pushed back the limits for the structural characterization of biomolecular assemblies. Large efforts have been devoted to increase both resolution and accuracy of the methods, probe into the smallest biomolecules as well as the largest macromolecular machineries, unveil transient complexes along with dynamic interaction processes, and, lately, dissect whole organism interactomes using high‐throughput strategies. However, the atomic description of such interactions, rarely reached by large‐scale projects in structural biology, remains indispensable to fully understand the subtleties of the recognition process, measure the impact of a mutation or predict the effect of a drug binding to a complex. Mixing even a limited amount of experimental and/or bioinformatic data with modeling methods, such as macromolecular docking, presents a valuable strategy to predict the three‐dimensional structures of complexes. Recent developments indicate that the docking community is seething to tackle the greatest challenge of adding the structural dimension to interactomes. © 2011 John Wiley & Sons, Ltd.This article is categorized under:

Molecular and Statistical Mechanics > Molecular Dynamics and Monte-Carlo Methods
Enhancing N, P, S‐Janus Head Tripod Ligands by Oxidation
Authors: Meinholz Margret M. , Stalke Dietmar 
Published: September 2011

AbstractIn this paper we present the synthesis of several sulfurdiimido phosphanyllithium complexes that are oxidised with oxygen, sulfur or selenium at the phosphorus atom. Starting from the PIII‐containing [Li{tBu2PCH2S(NSiMe3)2}]2 (1) we synthesised and structurally characterised [Li{tBu2P(E)CH2S(NSiMe3)2}]2 (E = O: 2,E = S: 4, E = Se: 5) and [Li2{tBu2PCH2S(NSiMe3)2}2(tBu2P(O)Me)](3). The oxidised and unoxidised species are discussed with respectto their coordination properties and in terms of ligand design. Acomparison to the potential polymerisation catalyst[(C3H7)Ni{tBu2PCH2S(NSiMe3)2}] is presented as well.
Synthesis, Structure, and Solubility Studies of a New Arsenato‐Polyoxovanadate Cluster Compound: (NH4)4[V12As8O40(H2O)]·4H2O
Authors: Wutkowski Adam , Evers Nils , Bensch Wolfgang 
Published: September 2011

AbstractAbstract. The new arsenato polyxoxvanadate (NH4)4[V12As8O40(H2O)]·4H2O (1) was obtained under solvothermal conditions using either a mixture of ethyl ether/H2O or ethanol/H2O acting as reducing agents. Compound 1 crystallizes in the orthorhombic space group Pnnm with a = 13.6740(3), b = 12.7378(5), c = 13.0580(3) Å, V = 2274.40(11) Å3, Z = 2. The central structural motif features an anionic cluster shell, which can be derived from the {V18O42} archetype cluster by replacing VO5 polyhedra by As2O5 units and omitting two VO5 square pyramids. The electronic situation of the cluster anion can be best described by the formula [V8IVV4VAs8IIIO40(H2O)]4–. The charge neutrality of the compound is achieved by NH4+ cations which occupy the free space between the clusters together with crystal H2O molecules. Thermal investigation shows a complex decomposition process occurring in at least three steps. Determination of the optical band gap classifies 1 as a semiconductor with a band gap of 2.8 eV. Solubility studies accompanied by IR spectroscopy, ESI‐MS, X‐ray powder diffractometry and elemental analysis demonstrate that the cluster is partially dissolved.
Risikoberechnungen beim autosomal-rezessiven Erbgang
Authors: Grimm T. , Fischer C. , Langer S. , Rudnik-Schöneborn S. , Zerres K. 
Published: September 2011

Zusammenfassung
Die Risikoberechnungen bei autosomal-rezessiven Erkrankungen können mithilfe des Bayesschen Rechentableaus durchgeführt werden. Die Hardy-Weinberg-Regel ist eine wichtige Grundlage, um A-priori-Wahrscheinlichkeiten zu bestimmen. Es wird demonstriert, wie sich gesunde Angehörige, Ergebnisse molekularer Tests und komplexe genetische Modelle berücksichtigen lassen und wie diese Parameter sich auf das Risiko auswirken. Als Beispiele für den autosomal-rezessiven Erbgang sind die zystische Fibrose (CF) und die infantile spinale Muskelatrophie (SMA) gewählt worden.