bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soy lecithin supplementation alters macrophage phagocytosis and lymphocyte response to concanavalin A: a study in alloxan‐induced diabetic rats
Authors: Miranda Dalva T. S. Z. , Batista Vanessa G. , Grando Fernanda C. C. , Paula Fernanda M. , Felício Caroline A. , Rubbo Gabriella F. S. , Fernandes Luiz C. , Curi Rui , Nishiyama Anita 
Published: October 2008

AbstractDietary soy lecithin supplementation decreases hyperlipidemia and influences lipid metabolism. Although this product is used by diabetic patients, there are no data about the effect of soy lecithin supplementation on the immune system. The addition of phosphatidylcholine, the main component of lecithin, to a culture of lymphocytes has been reported to alter their function. If phosphatidylcholine changes lymphocyte functions in vitro as previously shown, then it could also affect immune cells in vivo. In the present study, the effect of dietary soy lecithin on macrophage phagocytic capacity and on lymphocyte number in response to concanavalin A (ConA) stimulation was investigated in non‐diabetic and alloxan‐induced diabetic rats. Supplementation was carried out daily with 2 g kg−1 b.w. lecithin during 7 days. After that, blood was drawn from fasting rats and peritoneal macrophages and mesenteric lymph node lymphocytes were collected to determine the phospholipid content. Plasma triacylglycerol (TAG), total and HDL cholesterol and glucose levels were also determined. Lymphocytes were stimulated by ConA. The MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) dye reduction method and flow cytometry were employed to evaluate lymphocyte metabolism and cell number, respectively. Soy lecithin supplementation significantly increased both macrophage phagocytic capacity (+29%) in non‐diabetic rats and the lymphocyte number in diabetic rats (+92%). It is unlikely that plasma lipid levels indirectly affect immune cells, since plasma cholesterol, TAG, or phospholipid content was not modified by lecithin supplementation. In conclusion, lymphocyte and macrophage function were altered by lecithin supplementation, indicating an immunomodulatory effect of phosphatidylcholine. Copyright © 2008 John Wiley & Sons, Ltd.
Mapping the Isoprenoid Binding Pocket of PDEδ by a Semisynthetic, Photoactivatable N‐Ras Lipoprotein
Authors: Alexander Michael , Gerauer Marc , Pechlivanis Markos , Popkirova Boriana , Dvorsky Radovan , Brunsveld Luc , Waldmann Herbert , Kuhlmann Jürgen 
Published: October 2008

AbstractBiologically functional Ras isoforms undergo post‐translational modifications starting with farnesylation of the most C‐terminal cysteine. Combined with further processing steps, this isoprenylation allows for the anchoring of these proteins in endomembranes, where signal transduction events take place. The specific localization is subject to dynamic regulation and assumed to modulate the activity of Ras proteins by governing their spatiotemporal distribution. The δ subunit of phosphodiesterase (PDEδ) has attracted attention as a solubilization factor of isoprenylated Ras. In this study, we demonstrate that critical residues in the putative isoprenoid pocket of PDEδ can be mapped by coupling with a semisynthetic N‐Ras lipoprotein in which the native farnesyl group of the processed protein was replaced by a photoactivatable geranyl benzophenone moiety. The crosslinked product included parts of β‐sheet 9 of PDEδ, which contains the highly conserved amino acids V145 and L147. Modeling of the PDEδ–geranyl benzophenone (GerBP) complex supports the conclusion that the photolabeled sequence is embedded in the putative isoprenoid pocket of PDEδ.
Ancillary Ligands and Spectator Cations as Controlling Factors in the Construction of Coordination and Hydrogen‐Bonded Networks with the tert‐Bu‐CC⊃Agn (n=4, 5) Supramolecular Synthon
Authors: Zhao Liang , Wan Chong‐Qing , Han Jie , Chen Xu‐Dong , Mak Thomas C. W. 
Published: October 2008

AbstractSupramolecular networks constructed with the tBuCC⊃Agn (n=4 or 5) metal–ligand synthon and trifluoroacetate have been transformed through the introduction of ancillary terminal nitrile ligands, from acetonitrile through propionitrile to tert‐butyronitrile, giving rise to a 2D coordination network in AgCCtBu⋅3 AgCF3CO2⋅H2O (1), a 2D hydrogen‐bonded network in AgCCtBu⋅5 AgCF3CO2⋅4 CH3CN⋅H2O (2), a 2D hybrid coordination/hydrogen‐bonded network in AgCCtBu⋅3 AgCF3CO2⋅CH3CH2CN⋅2 H2O (3), and another 2D coordination network in AgCCtBu⋅4 AgCF3CO2⋅ (CH3)3CCN⋅2 H2O (4). Concomitantly, the linkage modes between adjacent ethynide‐bound Agn aggregates in these compounds are also changed. A layer‐type hydrogen‐bonded host lattice in isostructural AgCCtBu⋅4 AgCF3CO2⋅(R4N)(CF3CO2)⋅ 2 H2O (R4=BnMe3, 5; R4=Et4, 6; R4=nPr4, 7) is obtained by introducing quaternary ammonium cations as guest templates, which occupy the interstices and thereby mediate the interlayer separation. Use of the bulky nBu4N+ cation leads to disruption of the host network in AgCCtBu⋅4 AgCF3CO2⋅3[(nBu4N)(CF3CO2)]⋅H2O (8) with generation of a discrete dense nido‐Ag5 cluster.
Polysulfurated Pyrene‐Cored Dendrimers: Luminescent and Electrochromic Properties
Authors: Gingras Marc , Placide Virginie , Raimundo Jean‐Manuel , Bergamini Giacomo , Ceroni Paola , Balzani Vincenzo 
Published: October 2008

AbstractWe have synthesized a novel class of dendrimers, consisting of a polysulfurated pyrene core with appended poly(thiophenylene) dendrons (PyG0, PyG1, and PyG2, see Scheme 1), which exhibit remarkable photophysical and redox properties. In dichloromethane or cyclohexane solution they show a strong, dendron‐localized absorption band with a maximum at around 260 nm and a band in the visible region with a maximum at 435 nm, which can be assigned to the pyrene core strongly perturbed by the four sulfur substituents. The dendrimers exhibit a strong (Φ=0.6), short‐lived (τ=2.5 ns) core‐localized fluorescence band with maximum at approximately 460 nm in cyclohexane solution at 293 K. A strong fluorescence is also observed in dichloromethane solution at 293 K, in dichloromethane/chloroform rigid matrix at 77 K, and in the solid state (powder) at room temperature. The dendrimers undergo reversible chemical and electrochemical one‐electron oxidation with formation of a strongly colored deep blue radical cation. A second, reversible one‐electron oxidation is observed at more positive potential values. The photophysical and redox properties of the three dendrimers are finely tuned by the length of their branches. The strong blue fluorescence and the yellow to deep blue color change upon reversible one‐electron oxidation can be exploited for optoelectronic devices.
Size‐Specific, Colorimetric Detection of Counteranions by Using Helical Poly(phenylacetylene) Conjugated to L‐Leucine Groups through Urea Acceptors
Authors: Kakuchi Ryohei , Nagata Sachiko , Sakai Ryosuke , Otsuka Issei , Nakade Hiroshi , Satoh Toshifumi , Kakuchi Toyoji 
Published: October 2008

AbstractA colorimetric detection susceptible to the dimensions of guest counteranions has been demonstrated by using poly(phenylacetylene) with L‐leucine and urea functionalities (poly‐PA‐Leu). Poly‐PA‐Leu was prepared from N‐(4‐ethynylphenylcarbamoyl)‐L‐leucine ethyl ester (PA‐Leu) by using [Rh+{η6‐C6H5)B−(C6H5)3}(2,5‐norbornadiene)] as a catalyst. The biased helical conformation of poly‐PA‐Leu was demonstrated through Cotton effects in the circular dichroism (CD) spectra. The addition of ammonium salts, including tetra‐n‐butylammonium acetate, tetra‐n‐butylammonium chloride, and tetra‐n‐butylammonium bromide anions (CH3COO−, Cl−, and Br−), into the poly‐PA‐Leu solution intensified the CD responses of poly‐PA‐Leu, which is indicative of the chiral adjustability of anion recognition by using urea groups. In addition, the combination of poly‐PA‐Leu with the CH3COO−, Cl−, and Br− anions promoted large redshifts in the absorption spectra, thus providing dramatic color changes from pale yellow to red. Guest dependency in the CD and UV/Vis spectra was clearly correlated with the size of the counteranions. Fundamentally, the addition of tetra‐n‐butylammonium nitrate, tetra‐n‐butylammonium hydrogen sulfate, tetra‐n‐butylammonium perchlorate, tetra‐n‐butylammonium azide, tetra‐n‐butylammonium fluoride, and tetra‐n‐butylammonium iodide anions (NO3−, HSO4−, ClO4−, N3−, F−, and I−) has no effect on either the CD or UV/Vis profiles of poly‐PA‐Leu. The guest specificity observed in the CD and UV/Vis spectra clearly demonstrated the guest‐dimension selectivity of poly‐PA‐Leu in counteranion recognition.
Interaction of Dinuclear Ruthenium(II) Supramolecular Cylinders with DNA: Sequence‐Specific Binding, Unwinding, and Photocleavage
Authors: Malina Jaroslav , Hannon Michael J. , Brabec Viktor 
Published: October 2008

AbstractMetallosupramolecular chemistry was used to design a new class of synthetic agents, namely, tetracationic supramolecular cylinders, that bind strongly and noncovalently in the major groove of DNA. To gain additional information on interactions of the cylinders with DNA we explored DNA unwinding and sequence‐specific binding properties, as well as DNA photonuclease activity of ruthenium(II) metallosupramolecular cylinder [Ru2L3]4+, where L is a bis‐pyridylimine ligand. We found that [Ru2L3]4+ unwinds negatively supercoiled plasmid DNA and exhibits binding preference to regular alternating purine–pyrimidine sequences in a similar way to the [Fe2L3]4+ analogue. Photocleavage studies showed that, unlike [Fe2L3]4+, [Ru2L3]4+ induces single‐strand breaks on irradiation by visible and UVA light and cleaves DNA mainly at guanine residues contained preferentially in regularly alternating purine–pyrimidine nucleotides. As [Ru2L3]4+ binds and cleaves DNA in a sequence‐dependent manner, it may provide a useful tool for basic and applied biology, such as for controlled manipulation of the genome.
Biocatalytic Enantioselective Synthesis of N‐Substituted Aspartic Acids by Aspartate Ammonia Lyase
Authors: Weiner Barbara , Poelarends Gerrit J. , Janssen Dick B. , Feringa Ben L. 
Published: October 2008

AbstractThe gene encoding aspartate ammonia lyase (aspB) from Bacillus sp. YM55‐1 has been cloned and overexpressed, and the recombinant enzyme containing a C‐terminal His6 tag has been purified to homogeneity and subjected to kinetic characterization. Kinetic studies have shown that the His6 tag does not affect AspB activity. The enzyme processes L‐aspartic acid, but not D‐aspartic acid, with a Km of ≈15 mM and a kcat of ≈40 s−1. By using this recombinant enzyme in the reverse reaction, a set of four N‐substituted aspartic acids were prepared by the Michael addition of hydroxylamine, hydrazine, methoxylamine, and methylamine to fumarate. Both hydroxylamine and hydrazine were found to be excellent substrates for AspB. The kcat values are comparable to those observed for the AspB‐catalyzed addition of ammonia to fumarate (≈90 s−1), whereas the Km values are only slightly higher. The products of the enzyme‐catalyzed addition of hydrazine, methoxylamine, and methylamine to fumarate were isolated and characterized by NMR spectroscopy and HPLC analysis, which revealed that AspB catalyzes all the additions with excellent enantioselectivity (>97 % ee). Its broad nucleophile specificity and high catalytic activity make AspB an attractive enzyme for the enantioselective synthesis of N‐substituted aspartic acids, which are interesting building blocks for peptide and pharmaceutical synthesis as well as for peptidomimetics.
Mechanism of the Intramolecular Hydroamination of Alkenes Catalyzed by Neutral Indenyltitanium Complexes: A DFT Study
Authors: Müller Carsten , Koch Rainer , Doye Sven 
Published: October 2008

AbstractThree mechanistic pathways for the [Ind2TiMe2]‐catalyzed intramolecular hydroamination of alkenes have been investigated by employing density functional theory calculations on the possible intermediates and transition states. The results indicate that the reaction cycle proceeds via a Ti–imido–amido complex as the catalytically active species. However, at the moment, the question as to whether this imido–amido complex is involved in a [2+2]‐cycloaddition with the alkene or a newly proposed insertion of the alkene into a TiN single bond cannot be answered; the calculated barriers of both the insertion mechanism and the [2+2]‐cycloaddition mechanism are similar (143 vs. 136 kJ mol−1), and both pathways are in accordance with the experimentally observed rate law (first‐order dependence on the aminoalkene concentration). Interestingly, the newly proposed insertion mechanism that takes place by an insertion of the alkene moiety into the TiN single bond of an imido–amido complex seems to be much more likely than a mechanism that involves an alkene insertion into a TiN single bond of a corresponding trisamide. The latter mechanism, which has been proposed in analogy to rare‐earth‐metal‐catalyzed hydroamination reactions, can be ruled out for two reasons: a surprisingly high activation barrier (164 kJ mol−1) and the fact that the rate‐limiting insertion step is independent of the aminoalkene concentration. This is in sharp contrast to the experimental findings for indenyltitanium catalysts.
Exploring the Reactivity of C(sp3)‐Cyclometalated IrIII Compounds in Hydrogen Transfer Reactions
Authors: Azerraf Clarite , Gelman Dmitri 
Published: October 2008

AbstractThe manuscript describes the synthesis and full characterization of a new PC(sp3)P‐based cyclometalated IrIII complex that manifests an exceptional thermal stability, as well as outstanding reactivity in hydrogen transfer reactions. The described compound represents the first example of a new family of stable C(sp3)‐metalated compounds.
Physical Vapor Deposition of [EMIM][Tf2N]: A New Approach to the Modification of Surface Properties with Ultrathin Ionic Liquid Films
Authors: Cremer Till , Killian Manuela , Gottfried J. Michael , Paape Natalia , Wasserscheid Peter , Maier Florian , Steinrück Hans‐Peter 
Published: October 2008

AbstractUltrathin films of the ionic liquid (IL) 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMIM][Tf2N], are prepared on a glass substrate by means of an in situ thermal‐evaporation/condensation process under ultrahigh‐vacuum conditions. By using X‐ray photoelectron spectroscopy (XPS), it is demonstrated that the first layer of the IL film grows two dimensionally, followed by the three‐dimensional growth of successive layers. The first molecular layer consists of a bilayer, with the [EMIM]+ cations in contact to the surface and the [Tf2N]− anions at the vacuum side. The ultrathin IL films are found to be stable under ambient conditions.
Charge Transport through Molecular Rods with Reduced π‐Conjugation
Authors: Lörtscher Emanuel , Elbing Mark , Tschudy Meinrad , von Hänisch Carsten , Weber Heiko B. , Mayor Marcel , Riel Heike 
Published: October 2008

AbstractA series of oligophenylene rods of increasing lengths is synthesized to investigate the charge‐transport mechanisms. Methyl groups are attached to the phenyl rings to weaken the electronic overlap of the π‐subsystems along the molecular backbones. Out‐of‐plane rotation of the phenyl rings is confirmed in the solid state by means of X‐ray analysis and in solution by using UV/Vis spectroscopy. The influence of the reduced π‐conjugation on the resonant charge transport is studied at the single‐molecule level by using the mechanically controllable break‐junction technique. Experiments are performed under ultra‐high‐vacuum conditions at low temperature (50 K). A linear increase of the conductance gap with increasing number of phenyl rings (from 260 meV for one ring to 580 meV for four rings) is revealed. In addition, the absolute conductance of the first resonant peaks does not depend on the length of the molecular wire. Resonant transport through the first molecular orbital is found to be dominated by charge‐carrier injection into the molecule, rather than by the intrinsic resistance of the molecular wire length.
Interaction of NO2 with Model NSR Catalysts: Metal–Oxide Interaction Controls Initial NOx Storage Mechanism
Authors: Desikusumastuti Aine , Staudt Thorsten , Qin Zhihui , Happel Markus , Laurin Mathias , Lykhach Yaroslava , Shaikhutdinov Shamil , Rohr Friedemann , Libuda Jörg 
Published: October 2008

AbstractUsing scanning tunneling microscopy (STM), molecular‐beam (MB) methods and time‐resolved infrared reflection absorption spectroscopy (TR‐IRAS), we investigate the mechanism of initial NOx uptake on a model nitrogen storage and reduction (NSR) catalyst. The model system is prepared by co‐deposition of Pd metal particles and Ba‐containing oxide particles onto an ordered alumina film on NiAl(110). We show that the metal–oxide interaction between the active noble metal particles and the NOx storage compound in NSR model catalysts plays an important role in the reaction mechanism. We suggest that strong interaction facilitates reverse spillover of activated oxygen species from the NOx storage compound to the metal. This process leads to partial oxidation of the metal nanoparticles and simultaneous stabilization of the surface nitrite intermediate.
Efficient Catalytic Decomposition of Formic Acid for the Selective Generation of H2 and H/D Exchange with a Water‐Soluble Rhodium Complex in Aqueous Solution
Authors: Fukuzumi Shunichi , Kobayashi Takeshi , Suenobu Tomoyoshi 
Published: October 2008

AbstractFormic acid (HCOOH) decomposes efficiently to afford H2 and CO2 selectively in the presence of a catalytic amount of a water‐soluble rhodium aqua complex, [RhIII(Cp*)(bpy)(H2O)]2+ (Cp*=pentamethylcyclopentadienyl, bpy=2,2′‐bipyridine) in aqueous solution at 298 K. No CO was produced in this catalytic decomposition of HCOOH. The decomposition rate reached a maximum value at pH 3.8. No deterioration of the catalyst was observed during the catalytic decomposition of HCOOH, and the catalytic activity remained the same for the repeated addition of HCOOH. The rhodium‐hydride complex was detected as the catalytic active species that undergoes efficient H/D exchange with water. When the catalytic decomposition of HCOOH was performed in D2O, D2 was produced selectively. Such an efficient H/D exchange and the observation of a deuterium kinetic isotope effect in the catalytic decomposition of DCOOH in H2O provide valuable mechanistic insight into this efficient and selective decomposition process.
Preparing for the ‘real’ market: national patterns of institutional learning and company behaviour in the European Emissions Trading Scheme (EU ETS)
Authors: Engels Anita , Knoll Lisa , Huth Martin 
Published: October 2008

AbstractEuropean companies have reacted in different ways to the European Emissions Trading Scheme (EU ETS), Phase I. While some companies engaged in an active trading behaviour focused on additional revenues, others adopted a strategy orientated to mere compliance with the scheme and aimed for balanced accounts only. This article provides the outcomes of a survey on company behaviour under the EU ETS in Germany, the United Kingdom, the Netherlands and Denmark from 2005 to 2006, in which cross‐national differences in trading behaviour are linked to national patterns of policy implementation and the political economies in which companies operate. Thus, specific country patterns of institutional preparation and institutional learning for the ‘real’ CO2 allowance market in Phase II of the EU ETS (2008–2012) are sketched. Whereas Phase I is distinguished by a net over‐allocation of allowances, Phase II is expected to entail some level of scarcity of allowances. We argue that companies are prepared differently to meet the challenges of the future EU ETS. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment.
A European Perspective on recent trends in US climate policy
Authors: Moslener Ulf , Sturm Bodo 
Published: October 2008

AbstractWithout the participation of the United States, for many years the world's largest emitter of greenhouse gases, mitigation of global climate change seems hardly conceivable. Despite the US rejection of the Kyoto Protocol and the reluctance of the Bush administration to engage in post‐Kyoto negotiations, recent developments suggest that the US position towards climate policy might change in the medium run. This study provides an overview on current trends in US climate policy. We outline the main elements of national climate policy proposals and state‐level initiatives. Based on this overview, recent trends in US climate policy are related to the European approach to combat climate change. Furthermore, we elaborate on the aspects that may be important for Europe to design its own domestic and international climate policy in order to achieve the long‐term global goal of stabilizing greenhouse gas concentrations. While it seems likely that the US will take a leading role in international climate policy, it can also be expected to challenge the European position in many respects rather than to simply support any Kyoto‐type process. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment.
Cognitive load, trigger salience, and the facilitation of triggered displaced aggression
Authors: Vasquez Eduardo Antonio 
Published: October 2008

AbstractResearchers hypothesize that a state of limited cognitive processing capacity increases aggression. In the context of the triggered displaced aggression (TDA) paradigm, a 2 (Salience of triggering event: high/low) × 2 (Cognitive load at trigger: yes/no) × 2 (Cognitive load at aggression: yes/no) between participants experiment tested this hypothesis. Results showed that inducing cognitive load in previously provoked participants while they received a triggering provocation augmented aggression toward the target when the latter was highly salient. Affective reactions to the trigger partially mediated this effect. In contrast to expectation, however, inducing cognitive load while participants aggressed against their target did not affect aggression levels. Copyright © 2008 John Wiley & Sons, Ltd.
Shoes influence lower limb muscle activity and may predispose the wearer to lateral ankle ligament injury
Authors: Kerr Robin , Arnold Graham P. , Drew Tim S. , Cochrane Lynda A. , Abboud Rami J. 
Published: October 2008

AbstractLateral ankle ligaments are injured by hyperinversion of the foot. Foot position is controlled by the lower limb muscles. Awareness of foot position is impaired by wearing shoes. We aimed to determine the influence of wearing shoes upon muscle activity. Sixty‐two healthy subjects underwent the same measurements, barefoot and with standardized shoes in a random order. Electromyography (EMG) was recorded from the peroneus longus muscle in response to sudden and unanticipated inversion of the ipsilateral foot. Following foot inversion, the EMG signal showed an initial peak muscle contraction followed by a sustained smaller contraction. Both changes were significantly greater in shoes compared to the barefoot condition for all tested degrees of inversion. Muscle contraction following sudden inversion of the foot was significantly greater when wearing shoes. This greater muscular contraction may be an intrinsic mechanism to oppose the increased moment created by the inverted foot/shoe condition, and hence, may counter balance the increased tendency to injure the lateral ankle ligaments created by wearing shoes. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:318–324, 2009