bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intramolecular Electron Transfer in the Dihaem Cytochrome c Peroxidase of Pseudomonas aeruginosa
Authors: Lee Yong , Boycheva Svetlana , Brittain Thomas , Boyd Peter D. W. 
Published: July 2007

AbstractMutant forms of the enzyme cytochrome c peroxidase from Pseudomonas aeruginosa, in which the peroxidatic haem ligand (H71) and putative haem‐bridging amino acid (W94) have been mutated, were produced in an E. coli expression system as a means of investigating possible mechanisms of intramolecular electron transfer within the enzyme. EPR spectroscopy indicated the presence of a high‐spin, presumably five‐coordinate, peroxidatic haem site in the H71G and H71G/W94A mutants, whilst the W94A mutant apparently retained the normal six‐coordinate haem structures. In turnover experiments, these mutants show 55, 4, and <1 % activity, respectively, as compared to the wild‐type enzyme. The W94A mutant shows essentially no activity in turnover experiments. Circular dichroism spectroscopy indicates no measurable difference in the secondary structure of the H71G mutant from that of the native enzyme, whilst some small differences are observed for the double mutant. Treatment of the oxidised mutant proteins with hydrogen peroxide, in the absence of preactivation or exogenous reductants, yields products that suggest the formation of a tryptophan radical species in the case of the H71 mutant and the production of a porphyrin radical in the case of the double mutant. These results are discussed in terms of the intramolecular electron transfer in this enzyme.
Counterion‐Dependent Proton‐Driven Self‐Assembly of Linear Supramolecular Oligomers Based on Amino‐Calix[5]arene Building Blocks
Authors: Pappalardo Sebastiano , Villari Valentina , Slovak Sarit , Cohen Yoram , Gattuso Giuseppe , Notti Anna , Pappalardo Andrea , Pisagatti Ilenia , Parisi Melchiorre F. 
Published: July 2007

AbstractSelf‐assembly of a calix[5]arene bearing a 12‐aminododecyl pendant group on the lower rim into supramolecular oligomers through intermolecular iterative inclusion events is readily triggered by contact with acid solutions and is reversed to the amino monomer precursor by treatment with a base.1H NMR data are consistent with the formation of head‐to‐tail assemblies derived fromendo‐cavity inclusion of the alkylammonium moiety. Diffusion NMR and light‐scattering studies provide evidence for the presence of oligomers in solution and show that different counterions and concentrations result in different oligomer sizes, whereas ESI‐MS and SEM investigations, respectively, indicate that self‐assembly also takes place in the gas phase and in the solid state. The growth of these supramolecular oligomers is concentration‐dependent; however, as a consequence of the saline nature of the monomer, it also shows a distinct counterion‐dependence owing to ion‐pairing/solvation effects.
Constitutional Self‐Organization of Adenine–Uracil‐Derived Hybrid Materials
Authors: Arnal‐Hérault Carole , Barboiu Mihai , Pasc Andreea , Michau Mathieu , Perriat Pascal , van der Lee Arie 
Published: July 2007

AbstractThe alkoxysilane nucleobase adenine (A) and uracil (U) precursors described in this paper generate in solution a complex library of hydrogen‐bonded aggregates, which can be expressed in the solid state as discrete higher oligomers. The different interconverting outputs that nucleobases may form by oligomerization define a dynamic polyfunctional diversity that may be “extracted selectively” in solid state by sol–gel transcription, under the intrinsic stability of the system. After the sol–gel process, unique constitutional preference for specific geometries in hybrid materials is consistent with a preferential arrangement of nucleobase systems, favoring the self‐assembly by the Hoogsteen geometry. FTIR and NMR spectroscopy and X‐ray powder diffraction experiments demonstrate the formation of self‐organized hybrid supramolecular materials. Electron microscopy reveals the micrometric platelike morphology of the hybrid materials. The MA–U hybrid material is nanostructured in ordered circular domains of 5 nm in diameter of alternative light and dark rows with an one‐dimensional periodicity of 3.5 Å.
Prevalence of Renal Insufficiency in cancer patients and implications for anticancer drug management
Authors: Launay‐Vacher Vincent , Oudard Stéphane , Janus Nicolas , Gligorov Joseph , Pourrat Xavier , Rixe Olivier , Morere Jean‐François , Beuzeboc Philippe , Deray Gilbert ,   On behalf of the Renal Insufficiency and Cancer Medications (IRMA) Study Group
Published: July 2007

AbstractBACKGROUND.The Renal Insufficiency and Cancer Medications (IRMA) study is a French national observational study. The results from this study of nearly 5000 patients demonstrated the high prevalence of renal impairment in a population of patients with solid tumors.METHODS.Every cancer patient who presented at oncology departments that participated in the study over at least 1 of 2 predefined periods during 2004 were included. Renal function was calculated using Cockcroft‐Gault and abbreviated Modification of Diet in Renal Disease (aMDRD) formulae to estimate the prevalence of renal insufficiency (RI) according to the Kidney Disease Outcomes Quality Initiative‐Kidney Disease Improving Global Outcomes definition and stratification. Anticancer drugs were studied with regard to their potential renal toxicity and dosage adjustment.RESULTS.Of the 4684 patients from the 15 centers, 7.2% had serum creatinine levels >110 μmol/L. However, when they were assessed using Cockcroft‐Gault and aMDRD formulae, 57.4% and 52.9% of patients had abnormal renal function or RI, respectively. Of the 7181 anticancer drug prescriptions, 53.4% required dose adjustments for RI. Of the patients treated, 79.9% received at least 1 such drug. And 80.1% received potentially nephrotoxic drugs.CONCLUSIONS.RI was common in patients with cancer, and drug dosage adjustments often were necessary. Renal function should be evaluated in all cancer patients using either the Cockcroft‐Gault formula or the aMDRD formula, including patients with normal serum creatinine levels. In patients who are at high risk for drug toxicity, the dosage should be adapted to renal function, and the use of nephrotoxic therapies should be avoided whenever possible. Cancer 2007. © 2007 American Cancer Society.
Viewership of pro‐eating disorder websites: Association with body image and eating disturbances
Authors: Harper Kelley , Sperry Steffanie , Thompson J. Kevin 
Published: July 2007

AbstractObjective:To evaluate the association between pro‐eating disorder website viewership and concurrent levels of body dissatisfaction and eating disturbance.Method:A sample of 1575 women were surveyed for viewership of a variety of websites, including those promoting disordered eating (pro‐eating disorder) and those providing information about eating disorders (professional).Results:Individuals who frequented pro‐eating disorder sites had higher levels of body dissatisfaction and eating disturbance than a control group. The group who frequented only professional information websites, but not pro‐eating disorder websites, differed from controls on only one of the four measures of disturbance. The pro‐eating disorder group did not differ from the professional group on any measure.Conclusion:The findings offer moderate evidence indicating that viewers of pro‐eating disorder sites have higher levels of disturbance than a control sample of nonviewers, but limited evidence that those who view pro‐eating disorder sites differ from individuals who view professional sites offering information regarding eating disorders. The findings are discussed in light of the difficulty determining causality in this area of inquiry and a cautionary note regarding the potential iatrogenic effects of this type of research is offered. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2008
Gender and age differences in associations between peer dieting and drive for thinness
Authors: Gravener Julie A. , Haedt Alissa A. , Heatherton Todd F. , Keel Pamela K. 
Published: July 2007

AbstractObjective:To examine associations between peer dieting and drive for thinness (DT) in men and women of three age groups and to compare rates of perceived vs. reported peer dieting.Method:Data came from an epidemiological study in which surveys were completed by women (n = 1,468) and men (n = 592) from three age groups: late adolescent (mean ± SD age: 20.0 ± 1.6 years), adult (30.0 ± 1.6), and midlife (40.1 ± 2.0).Results:Significant associations were found between perceived peer dieting and DT in women and men. For women, associations were strongest in late adolescents for same‐sex peers. Associations in men did not differ by age group or peer sex. Expected gender differences in the strength of associations were not found. Reported dieting occurred at or below rates perceived for peers.Conclusion:Results may partially account for why DT has been found to decline with age in women, but not men. Longitudinal research is needed to support cross‐sectional findings. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2008
CXCL12‐induced partitioning of flotillin‐1 with lipid rafts plays a role in CXCR4 function
Authors: Giri Banabihari , Dixit Vishwa D. , Ghosh Manik C. , Collins Gary D. , Khan Islam U. , Madara Karen , Weeraratna Ashani T. , Taub Dennis D. 
Published: July 2007

AbstractLipid rafts play an important role in signal integration and in the cellular activation of a number of cytokine and growth factor receptors. It has recently been demonstrated that flotillin proteins are recruited to lipid raft microdomains upon cellular activation and play a role in neural cell regeneration, receptor signaling and lymphocyte activation. However, little is known about the relevance of the flotillin proteins during T cell responses to chemoattractant stimulation. To this end, cytoplasmic and lipid raft fractions from human T cells were analyzed for flotillin protein redistribution prior to and after CXCL12 stimulation. Flotillin‐1, but not flotillin‐2, redistributes to lipid rafts upon CXCR4 ligation. Moreover, in CXCL12‐treated T cells, flotillin‐1 also associates with several raft proteins including LAT, CD48 and CD11a but not Lck. In addition, an increase in CXCR4 association with flotillin‐1 in lipid rafts was observed after chemokine treatment. RNAi technology was also utilized to inhibit the expression of flotillin‐1, resulting in an inhibition of CXCL12‐mediated signaling, function and CXCR4 recruitment into lipid rafts. Together, these data suggest that the increased association of cellular flotillin‐1 with lipid raft microdomains during chemokine exposure may play an important role in chemokine receptor signaling and receptor partitioning with lipid rafts.
Quinacrine inhibits the epidermal dendritic cell migration initiating T cell‐mediated skin inflammation
Authors: Gorbachev Anton V. , Gasparian Alexander V. , Gurova Katerina V. , Gudkov Andrei V. , Fairchild Robert L. 
Published: July 2007

AbstractQuinacrine (QC) is an anti‐inflammatory drug that has been used for the treatment of malaria and rheumatoid diseases. The mechanism(s) underlying the anti‐inflammatory activity of QC remains poorly understood. We recently reported the QC‐mediated inhibition of the NF‐κB pathway using an in vitro model. To test this potential mechanism in vivo, we used the contact hypersensitivity response (CHS) to chemical allergen sensitization and challenge in mice as a model of skin inflammation. The results indicated that QC treatment inhibited NF‐κB activation in the skin during allergen sensitization. This inhibition was reflected by decreased mRNA expression and protein production of the NF‐κB‐dependent cytokines TNF‐α and IL‐1β and the chemokine CCL21 in the skin. The decreases in these cytokines resulted in reduced migration of allergen‐presenting dendritic cells from the skin into skin‐draining lymph nodes and markedly decreased activation of effector CD8+ T cells for the CHS response to allergen challenge (inhibitory concentration 50% or IC50 was 55 mg/kg). These findings reveal a previously unrecognized mechanism of QC‐mediated inhibition of inflammation.
Leptin‐mediated cytokine release and migration of eosinophils: Implications for immunopathophysiology of allergic inflammation
Authors: Wong Chun Kwok , Cheung Phyllis F.‐Y. , Lam Christopher W. K. 
Published: July 2007

AbstractLeptin is a pleiotropic adipocyte‐derived cytokine used in hypothalamic regulation of body weight and modulation of immune response by stimulating T cells, macrophages and neutrophils. Leptin has been shown to be an eosinophil survival factor. We examined the immunopathological mechanisms for the activation of human eosinophils from healthy volunteers by leptin in allergic inflammation. Adhesion molecules, cytokines and cell migration were assessed by flow cytometry, ELISA and Boyden chamber assay, respectively. Intracellular signaling molecules were investigated by membrane array and Western blot. Leptin could up‐regulate cell surface expression of adhesion molecule ICAM‐1 and CD18 but suppress ICAM‐3 and L‐selectin on eosinophils. Leptin could also stimulate the chemokinesis of eosinophils, and induce the release of inflammatory cytokines IL‐1β and IL‐6, and chemokines IL‐8, growth‐related oncogene‐α and MCP‐1. We found that leptin‐mediated induction of adhesion molecules, release of cytokines and chemokines, and chemokinesis were differentially regulated by the activation of ERK, p38 MAPK and NF‐κB. In view of the above results and elevated production of leptin in patients with allergic diseases such as atopic asthma and atopic dermatitis, leptin could play crucial immunopathophysiological roles in allergic inflammation by activation of eosinophils via differential intracellular signaling cascades.
Introduction of Modified Electronic Parameters – Searching for a Unified Ligand Properties Scale through the Electrophilicity Index Concept
Authors: Makedonas Christodoulos , Mitsopoulou Christiana A. 
Published: July 2007

AbstractIn order to quantify the contribution of mainly, but not only, diimine ligands to the electronic properties of the corresponding complexes, two novel indices, namely modified electronic parameters (ModEP) and electrophilicity, ω, are introduced and discussed in this report. First, we introduce the concept of ModEP, a novel scale relating to the electronic properties of diimine ligands. Mainly on the basis of well‐characterized M(diimine)(dithiolato) complexes (M = Pt, Pd, or Ni), we derive the contribution of the diimine ligand to the reduction potentials of the complexes, and incorporating its contribution to the main charge‐transfer band of the UV/Vis spectra, we obtain our ModEP values. The applicability of the introduced scale to several other classes of diimine compounds (W, Re, and Ru) is then tested. The performance of our scale in predicting the values of the reduction potentials and the position of the charge‐transfer bands is very satisfactory. With this approach, some interesting aspects of ligand coordination were revealed. Next, we employ the recently introduced electrophilicity index ω, in order to correlate our ModEP scale with various other empirical scales that are already known and extensively used. This permits us to unify most known scales, which were primarily derived for different types of ligands (e.g. ModEP for diimines, Tolman's for phosphanes). The proposed method of ω calculation (at the semiempirical AM1 level) avoids any experimental limitation and can be employed even for ligands that are not yet experimentally available, whereas its correlation to the known scales would immediately provide the properties of the compound. This supports the idea that the electrophilicity index could become a powerful tool in coordination and organometallic chemistry.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis, Separation and UV/Vis Spectroscopy of Pyrazino‐quinoxalino‐porphyrazine Macrocycles
Authors: Musil Zbynek , Zimcik Petr , Miletin Miroslav , Kopecky Kamil , Lenco Juraj 
Published: July 2007

AbstractUnsymmetrical metal‐free and zinc complexes of pyrazino‐quinoxalino‐porphyrazines (PQP) bearing eight diethylamino groups have been synthesized by statistical tetramerization of 2,3‐bis(diethylamino)quinoxaline‐6,7‐dicarbonitrile and 5,6‐bis(diethylamino)pyrazine‐2,3‐dicarbonitrile in lithium butanolate. For this purpose, a new heteroatom‐substituted quinoxaline precursor, 2,3‐dichloro‐6,7‐dicarbonitrile, was prepared and characterized. It is a flexible starting material for new building blocks of quinoxaline‐6,7‐dicarbonitrile derivatives. All the PQPs (including adjacent and opposite isomers) from the statistical mixture were detected and separated by column chromatography on silica and characterized by MALDI‐TOF mass spectrometry, IR, UV/Vis and NMR spectroscopy. The effect of the insertion of benzene rings into the tetrapyrazinoporphyrazine (TPP) system is discussed. Each benzene ring insertion into the TPP system causes a bathochromic shift of 22 nm; the dependence is linear. The final tetra[6,7]quinoxalinoporphyrazines were red‐shifted to 744 and 763 nm for the zinc and metal‐free derivative, respectively. Splitting of the Q‐band was observed for PQPs with lower symmetry.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
One‐Pot Synthesis of Core‐Modified Rubyrin, Octaphyrin, and Dodecaphyrin: Characterization and Nonlinear Optical Properties
Authors: Kumar Rajeev , Misra Rajneesh , Chandrashekar Tavarekere K. , Nag Amit , Goswami Debabrata , Suresh Eringathodi , Suresh Cherumuttathu H. 
Published: July 2007

AbstractModified 26π rubyrin, 36π octaphyrin, and 54π dodecaphyrin systems have been synthesized in moderately good yields through acid‐catalyzed condensations of terthiophene diols and tripyrranes. The product distributions are decided both by the acid catalyst concentration and by the nature of the meso substituents. For example, a new isomer of [26]hexaphyrin(1.1.1.1.0.0) (rubyrin) was obtained with 0.3 equiv. of p‐toluenesulfonic acid, when the meso substituent was mesityl in at least one of the precursors. A change of the mesityl substituent for a p‐methoxy substituent in terthiophene diol resulted in the formation of a [3 + 3 + 3 + 3] condensation product – [54]dodecaphyrin(1.1.1.1.0.0.1.1.1.1.0.0) – in addition to the expected rubyrin. Furthermore, an increase in the acid concentration to 0.6 equiv. resulted in the formation of a new [36]octaphyrin(1.1.1.1.1.1.0.0), in addition to the rubyrin and dodecaphyrin. A single‐crystal X‐ray analysis of octaphyrin represents the first example of a planar conformation of an octaphyrin with six meso links. In rubyrin 19, one thiophene ring, opposite to the terthiophene subunit, is inverted, while in octaphyrin 30 one pyrrole ring and two thiophene rings are inverted. The various conformational possibilities tested for the unsubstituted dodecaphyrin 28, at semiempirical level, suggest that the most stable conformation is a figure‐eight. The final geometry optimization of figure‐eight dodecaphyrin was done at the B3LYP/6‐31G* level of DFT. Octaphyrins and dodecaphyrins bind trifluoroacetate anion effectively in their diprotonated forms, the binding constants (K) being 638 M–1 for dodecaphyrin 28, and 415 M–1 for octaphyrin 30. Electrochemical data reveal HOMO destabilization with increasing π electron conjugation, consistently with the large red shifts of the absorption bands. Preliminary studies on the use of these expanded porphyrins as third‐order NLO materials were followed by measurements of their two‐photon absorption (TPA) cross‐sections [σ(2)]. The σ(2) values increase upon going from the 26π rubyrins to the 54π dodecaphyrins, confirming our earlier observation that increases in π‐conjugated electrons increase the TPA values.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
An alternating Crank–Nicolson method for the numerical solution of the phase‐field equations using adaptive moving meshes
Authors: Tan Zhijun , Huang Yanghong 
Published: July 2007

AbstractAn alternating Crank–Nicolson method is proposed for the numerical solution of the phase‐field equations on a dynamically adaptive grid, which automatically leads to two decoupled algebraic subsystems, one is linear and the other is semilinear. The moving mesh strategy is based on the approach proposed by Li et al. (J. Comput. Phys. 2001; 170:562–588) to separate the mesh‐moving and partial differential equation evolution. The phase‐field equations are discretized by a finite volume method in space, and the mesh‐moving part is realized by solving the conventional Euler–Lagrange equations with the standard gradient‐based monitors. The algorithm is computationally efficient and has been successfully used in numerical simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Decomposition methods for time‐domain Maxwell's equations
Authors: Huang Zhi‐Xiang , Sha Wei , Wu Xian‐Liang , Chen Ming‐Sheng 
Published: July 2007

AbstractDecomposition methods based on split operators are proposed for numerical integration of the time‐domain Maxwell's equations for the first time. The methods are obtained by splitting the Hamiltonian function of Maxwell's equations into two analytically computable exponential sub‐propagators in the time direction based on different order decomposition methods, and then the equations are evaluated in the spatial direction by the staggered fourth‐order finite‐difference approximations. The stability and numerical dispersion analysis for different order decomposition methods are also presented. The theoretical predictions are confirmed by our numerical results. Copyright © 2007 John Wiley & Sons, Ltd.
Equity swaps in a LIBOR market model
Authors: Wu Ting‐Pin , Chen Son Nan 
Published: July 2007

AbstractThis study extends the BGM (A. Brace, D. Gatarek, & M. Musiela, 1997) interest rate model (the London Interbank Offered Rate [LIBOR] market model) by incorporating the stock price dynamics under the martingale measure. As compared with traditional interest rate models, the extended BGM model is both appropriate for pricing equity swaps and easy to calibrate. The general framework for pricing equity swaps is proposed and applied to the pricing of floating‐for‐equity swaps with either constant or variable notional principals. The calibration procedure and the practical implementation are also discussed. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:893–920, 2007