bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study on the Molecular Dimension and Configuration of Polymer and Its Flow Characteristics from Electrolyte Effect
Authors: LU Xiangguo , WANG Xiaoyan , JIANG Weidong 
Published: May 2009

AbstractMolecular clew dimension and configuration of polymer, and flow characteristics of polymer solution were studied from electrolyte effect, by making use of dynamic light scattering (DLS), scanning electron microscopy (SEM), apparent viscosity method and core flow experiment. It can be observed that with the electrolyte concentration increasing, there exists a variation trend of "decreasing, increasing and decreasing again" to the molecular clew dimension of the polymer. The compression action of Ca2+or Mg2+to the double electrode layer of polymer molecules is more powerful by comparison against Na+, which results in that Ca2+and Mg2+have a more extensive effect on the viscosity of polymer solution, and clew dimensions and their distribution. With the electrolyte concentration increasing, the polymer molecular configuration of multi‐layer stereoscopic random reticulation transformed into a dendritic one. During the succeeding water flooding, the variation degree of injection pressure of core was mainly determined by the swelling extent of molecular clew of retained polymer and the produced amount of polymer. And the bigger the molecular weight of polymer is, the stronger the compression or swelling action of electrolyte to the molecule clews is, and the greater the increasing degree of injection pressure during succeeding water flooding is. The greater difference of electrolyte concentrations in used water between polymer flooding and succeeding water flooding can result in greater increasing degree of injection pressure during the succeeding water flooding. So, an advisable increasing in difference of electrolyte concentrations in used water between the polymer flooding and succeeding water flooding was proposed when designing the polymer flooding performance in oilfields, which has promising result for improving effect of polymer flooding.
Synthesis of Soluble Fluorene‐polyimino Ketone
Authors: LUO Xuan , CHANG Guanjun , WANG Qingfu , JIAO Wenxiu , ZHANG Lin , LIN Runxiong 
Published: May 2009

AbstractBased on the 9,9‐di(4‐anilinyl)fluorene, structurally different fluorene‐polyimino ketones have been obtained by the Buchwald‐Hartwig cross coupling reaction. Their structure and performance have been characterized by FT‐IR, 1H NMR, UV‐vis and thermal analysis. The results show an agreement with the proposed structure, which possesses high glass transition temperature (Tg>250 °C) and good thermal stability with high decomposition temperatures in nitrogen atmosphere (TD>520 °C). Additionally, the polymers synthesized showed good solubility, which can be dissolved in common organic solvent CHCl3 at room temperature.
A spectrally efficient frequency diversity technique for single‐carrier modulations with frequency division multiplexing
Authors: Araújo Teresa , Dinis Rui 
Published: May 2009

AbstractWhen the number of relevant propagation paths between the transmitter and the receiver is small and/or when they are not separable (i.e. the difference between the corresponding delays is smaller than the symbol duration), we can have deep fading effects and poor performance, especially for slow‐varying channels. In this case, the use of diversity techniques is strongly recommendable.In this paper, we consider an single‐carrier‐based (SC) block transmission, employing frequency domain equalisation (FDE) receivers and we present a frequency diversity technique that allows high spectral efficiencies. As with conventional frequency diversity techniques,Lreplicas of a given signal are transmitted atLdifferent frequencies. However, contrarily to conventional frequency diversity schemes, up toLusers can share this set ofLfrequency bands. Since this leads to strong interference levels, we propose an iterative, frequency‐domain receiver where all the users sharing theLfrequencies are jointly detected.Our performance results show that the proposed frequency diversity scheme allows high diversity gains, while keeping the spectral efficiency of conventional SC schemes. Moreover, we can cope with channels that can be severely time‐dispersive and/or can have deep fading effects. Copyright © 2009 John Wiley & Sons, Ltd.
Genomic and clinical analyses of 2p24 and 12q13‐q14 amplification in alveolar rhabdomyosarcoma: A report from the Children's Oncology Group
Authors: Barr Frederic G. , Duan Fenghai , Smith Lynette M. , Gustafson Donna , Pitts Mandy , Hammond Sue , Gastier‐Foster Julie M. 
Published: May 2009

AbstractAlveolar rhabdomyosarcoma (ARMS) is an aggressive pediatric cancer that is related to the skeletal muscle lineage and characterized by recurrent chromosomal translocations. Within the ARMS category, there is clinical and genetic heterogeneity, consistent with the premise that “primary” genetic events collaborate with “secondary” events to give rise to subsets with varying clinical features. Previous studies demonstrated that genomic amplification occurs frequently in ARMS. In the current study, we used oligonucleotide arrays to localize two common amplicons to the 2p24 and 12q13‐q14 chromosomal regions. Based on the copy number array data, we sublocalized the minimum common regions of 2p24 and 12q13‐q14 amplification to a 0.83 Mb region containing the DDX1 and MYCN genes, and a 0.55 Mb region containing 27 genes, respectively. Using fluorescent in situ hybridization assays to measure copy number of the 2p24 and 12q13‐q14 regions in over 100 cases, we detected these amplicons in 13% and 12% of cases, respectively. Comparison with fusion status revealed that 2p24 amplification occurred preferentially in cases positive for PAX3‐FOXO1 or PAX7‐FOXO1 while 12q13‐q14 amplification occurred preferentially in PAX3‐FOXO1‐positive cases. Expression studies demonstrated that MYCN was usually overexpressed in cases with 2p24 amplification while multiple genes were overexpressed in cases with 12q13‐q14 amplification. Finally, although 2p24 amplification did not have a significant association with clinical outcome, 12q13‐q14 amplification was associated with significantly worse failure‐free and overall survival that was independent of gene fusion status. © 2009 Wiley‐Liss, Inc.
Human immunodeficiency virus and hepatitis C infections induce distinct immunologic imprints in peripheral mononuclear cells # †
Authors: Kottilil Shyam , Yan Michael Y. , Reitano Kristin N. , Zhang Xiaozhen , Lempicki Richard , Roby Gregg , Daucher Marybeth , Yang Jun , Cortez Karoll J. , Ghany Marc , Polis Michael A. , Fauci Anthony S. 
Published: May 2009

Abstract
Coinfection with hepatitis C virus (HCV) is present in one-third of all human immunodeficiency virus (HIV)-infected individuals in the United States and is associated with rapid progression of liver fibrosis and poor response to pegylated interferon (IFN) and ribavirin. In this study we examined gene expression profiles in peripheral blood mononuclear cells (PBMCs) from different groups of individuals who are monoinfected or coinfected with HIV and HCV. Data showed that HIV and HCV viremia up-regulate genes associated with immune activation and immunoregulatory pathways. HCV viremia is also associated with abnormalities in all peripheral immune cells, suggesting a global effect of HCV on the immune system. Interferon-α-induced genes were expressed at a higher level in PBMCs from HIV-infected individuals. HCV and HIV infections leave distinct profiles or gene expression of immune activation in PBMCs. HIV viremia induces an immune activated state; by comparison, HCV infection induces immunoregulatory and proinflammatory pathways that may contribute to progression of liver fibrosis. Conclusion: An aberrant type-I IFN response seen exclusively in HIV-infected individuals could be responsible for the poor therapeutic response experienced by HIV/HCV coinfected individuals receiving interferon-α-based current standard of care. (Hepatology 2009;50:34–45.)
Aggravation by prostaglandin E2 of interleukin-6-dependent insulin resistance in hepatocytes #
Authors: Henkel Janin , Neuschäfer-Rube Frank , Pathe-Neuschäfer-Rube Andrea , Püschel Gerhard P. 
Published: May 2009

Abstract
Hepatic insulin resistance is a major contributor to fasting hyperglycemia in patients with metabolic syndrome and type 2 diabetes. Circumstantial evidence suggests that cyclooxygenase products in addition to cytokines might contribute to insulin resistance. However, direct evidence for a role of prostaglandins in the development of hepatic insulin resistance is lacking. Therefore, the impact of prostaglandin E2 (PGE2) alone and in combination with interleukin-6 (IL-6) on insulin signaling was studied in primary hepatocyte cultures. Rat hepatocytes were incubated with IL-6 and/or PGE2 and subsequently with insulin. Glycogen synthesis was monitored by radiochemical analysis; the activation state of proteins of the insulin receptor signal chain was analyzed by western blot with phosphospecific antibodies. In hepatocytes, insulin-stimulated glycogen synthesis and insulin-dependent phosphorylation of Akt-kinase were attenuated synergistically by prior incubation with IL-6 and/or PGE2 while insulin receptor autophosphorylation was barely affected. IL-6 but not PGE2 induced suppressors of cytokine signaling (SOCS3). PGE2 but not IL-6 activated extracellular signal-regulated kinase 1/2 (ERK1/2) persistently. Inhibition of ERK1/2 activation by PD98059 abolished the PGE2-dependent but not the IL-6-dependent attenuation of insulin signaling. In HepG2 cells expressing a recombinant EP3-receptor, PGE2 pre-incubation activated ERK1/2, caused a serine phosphorylation of insulin receptor substrate 1 (IRS1), and reduced the insulin-dependent Akt-phosphorylation. Conclusion: PGE2 might contribute to hepatic insulin resistance via an EP3-receptor-dependent ERK1/2 activation resulting in a serine phosphorylation of insulin receptor substrate, thereby preventing an insulin-dependent activation of Akt and glycogen synthesis. Since different molecular mechanisms appear to be employed, PGE2 may synergize with IL-6, which interrupted the insulin receptor signal chain, principally by an induction of SOCS, namely SOCS3. (Hepatology 2009.)
Free energy profiles of amino acid side chain analogs near water‐vapor interface obtained via MD simulations
Authors: Shaytan Alexey K. , Ivanov Victor A. , Shaitan Konstantin V. , Khokhlov Alexei R. 
Published: May 2009

AbstractSolvation of 13 neutral amino acid side chain analogs at water–vapor interface was studied by computing high precision free energy profiles of the molecules across the interface using molecular dynamics (MD) simulations. The SPC water model (Berendsen, H. J. C., Postma, J. P. M., van Gunsteren, W. F., Hermans, P. A. K. J., Dixon, R., Cornell, W., Fox, T., Chipot, C., Pohorille, A. In: Wilkinson, A., Weiner, P. and van Gunsteren, W. F. editors. Intermolecular Forces, 1981, 3, 331) and OPLS‐AA (Jorgensen et al., J Am Chem Soc, 1996, 118, 11225) potential parameter sets were used. A rigorous approach for the computation of high precision free energy profiles at water–vapor interface using constraint force technique is implemented. Methodology of obtaining high precision potential of mean force (PMF) profiles free of simulation artifacts in MD simulations is outlined and discussed. The accuracy of the calculations is examined by comparing the hydration free energies of studied solutes obtained from PMF calculations and separately using Bennett acceptance ratio technique by decoupling solvent‐solute interactions in the bulk. All molecules exhibit a free energy minimum at interface. No significant desolvation barrier is observed for any of the studied species. Adsorption energies for studied molecules at water–vapor interface are estimated and compared with experimental observations. We find that for modeled neutral compounds pronounced surface influence on solute solvation vanishes already at 6–7 Å behind the water surface as the solvation free energy approaches the bulk value. The possibility of force field refinement using adsorption free energies is outlined. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010
Quantum control implemented as combinatorial optimization
Authors: Strohecker Traci , Rabitz Herschel 
Published: May 2009

AbstractOptimal control theory provides a general means for designing controls to manipulate quantum phenomena. Traditional implementation requires solving coupled nonlinear equations to obtain the optimal control solution, whereas this work introduces a combinatorial quantum control (CQC) algorithm to avoid this complexity. The CQC technique uses a predetermined toolkit of small time step propagators in conjunction with combinatorial optimization to identify a proper sequence for the toolkit members. Results indicate that the CQC technique exhibits invariance of search effort to the number of system states and very favorable scaling upon comparison to a standard gradient algorithm, taking into consideration that CQC is easily parallelizable. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010
Properties of halogen atoms for representing intermolecular electrostatic interactions related to halogen bonding and their substituent effects
Authors: Torii Hajime , Yoshida Masaki 
Published: May 2009

AbstractThe electrostatic properties of halogen atoms are studied theoretically in relation to their ability of halogen bonding, which is an attractive intermolecular interaction of a covalently bonded halogen atom with a negatively charged atom of a neighboring molecule. The electric quadrupole (of electronic origin) with a positive zz component Θzz of a covalently bonded halogen atom, where the z axis is taken along the covalent bond involving the halogen atom, is mainly responsible for the attractive electrostatic interaction with a negatively charged atom. This positive Θzz is an intrinsic property of halogen atoms with the px2py2pz configuration of the valence electronic shell, as shown by ab initio molecular orbital calculations for isolated halogen atoms with this electronic configuration, and increases in the order of F < Cl < Br < I, in parallel with the known general sequence of the strength of halogen bonding. For halogen‐containing aromatic compounds, the substituent effects on the electrostatic properties are also studied. It is shown that the magnitude of Θzz and the electric field originating from it are rather insensitive to the substituent effect, whereas the electric field originating from atomic partial charges has a large substituent effect. The latter electric field tends to partially cancel the former. The extent of this partial cancellation is reduced in the order of Cl < Br < I and is also reducible by proper substitution on or within the six‐membered ring of halobenzene. Perspectives on the development of potential function parameters applicable to halogen‐bonding systems are also briefly discussed. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010
Reconstructing the equilibrium Boltzmann distribution from well‐tempered metadynamics
Authors: Bonomi M. , Barducci A. , Parrinello M. 
Published: May 2009

AbstractMetadynamics is a widely used and successful method for reconstructing the free‐energy surface of complex systems as a function of a small number of suitably chosen collective variables. This is achieved by biasing the dynamics of the system. The bias acting on the collective variables distorts the probability distribution of the other variables. Here we present a simple reweighting algorithm for recovering the unbiased probability distribution of any variable from a well‐tempered metadynamics simulation. We show the efficiency of the reweighting procedure by reconstructing the distribution of the four backbone dihedral angles of alanine dipeptide from two and even one dimensional metadynamics simulation. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009
Application of the topological analysis of the electronic localization function to archetypical [Pb(II)Ln]pcomplexes: The bonding of Pb2+revisited
Authors: van Severen Marie‐Céline , Gourlaouen Christophe , Parisel Olivier 
Published: May 2009

AbstractThe coordination of neutral ligands (L =OC, HCN,NH3,PH3,SH2, HNCOand H2O) to Pb2+is investigated and analyzed by means of the topological analysis of the Electronic Localization Function (ELF). It is shown that the mean charge density of theV(Pb) basin (〈ρ〉V(Pb)) can reach a ligand‐independent limiting value fromn= 6, a coordination number from which the [PbLn]2+complexes adopt holodirected structures. The investigations performed on anionic series (L = HS−,OH−,CN−, F−, Cl−, and Br−) lead to optimized stable structures in which the coordination number does not exceedn= 4, even in the presence of a model aqueous solvent. This different behavior with respect to the neutral ligand series is interpreted by means of natural populations and electrostatic repulsions. The main result of this contribution is that stable Pb(II) complexes could be those exhibiting reasonable values of 〈ρ〉V(Pb), namely those not exceeding the saturation plateau evidenced in the present piece of work. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010
Excess electron is trapped in a large single molecular cage C60F60
Authors: Wang Yin‐Feng , Li Zhi‐Ru , Wu Di , Sun Chia‐Chung , Gu Feng‐Long 
Published: May 2009

AbstractA new kind of solvated electron systems, sphere‐shaped e−@C60F60 (Ih) and capsule‐shaped e−@C60F60 (D6h), in contrast to the endohedral complex M@C60, is represented at the B3LYP/6‐31G(d) + dBF (diffusive basis functions) density functional theory. It is proven, by examining the singly occupied molecular orbital (SOMO) and the spin density map of e−@C60F60, that the excess electron is indeed encapsulated inside the C60F60 cage. The shape of the electron cloud in SOMO matches with the shape of C60F60 cage. These cage‐like single molecular solvated electrons have considerably large vertical electron detachment energies VDE of 4.95 (Ih) and 4.67 eV (D6h) at B3LYP/6‐31+G(3df) + dBF level compared to the VDE of 3.2 eV for an electron in bulk water (Coe et al., Int Rev Phys Chem 2001, 20, 33) and that of 3.66 eV for e−@C20F20 (Irikura, J Phys Chem A 2008, 112, 983), which shows their higher stability. The VDE of the sphere‐shaped e−@C60F60 (Ih) is greater than that of the capsule‐shaped e−@C60F60 (D6h), indicating that the excess electron prefers to reside in the cage with the higher symmetry to form the more stable solvated electron. It is also noticed that the cage size [7.994 (Ih), 5.714 and 9.978 Å (D6h) in diameter] is much larger than that (2.826 Å) of (H2O)20− dodecahedral cluster (Khan, Chem Phys Lett 2005, 401, 85). © 2009 Wiley Periodicals, Inc. J Comput Chem 2010
Sterilization system for air purifier by combining ultraviolet light emitting diodes with TiO2
Authors: Huang Xiaohui , Wang Huaibing , Yin Song , Chen Xiaorong , Chen Wei , Yang Hui 
Published: May 2009

AbstractBACKGROUND: Ultraviolet light emitting diodes (UV LEDs) were used as a light source in TiO2 photocatalysis because of their many advantages, such as, long life, safety, low pollution, etc. In this experiment, a light source panel was successfully fabricated with UV LEDs, the light intensities of which were relatively uniform.RESULTS: The sterilization process comprised two steps. First, an aerosol was blocked by high efficient particulate air (HEPA) filter paper coated with TiO2 photocatalyst. Second, Staphylococcus aureus in the aerosol decreased gradually in the photocatalysis process of UV LED/TiO2. After 52 h irradiation all the S. aureus were killed.CONCLUSION: The UV LED light source panel had a larger surface for irradiation than a mercury lamp. Thus, its sterilization efficiency was much better than that of traditional methods. The feasibility of UV LED/TiO2 for photocatalysis was proved. Copyright © 2009 Society of Chemical Industry
Lysosomal and alkaline phosphatase activity indicate macromolecule transport across the uterine epithelium in two viviparous skinks with complex placenta
Authors: Biazik Joanna M. , Thompson Michael B. , Murphy Christopher R. 
Published: May 2009

AbstractIn addition to water and small inorganic ions, macromolecules traverse the uterine epithelium in viviparous skinks to be absorbed by the developing fetus. In some species of lizards with complex placenta, the paracellular pathway across the uterine epithelium becomes tighter and more highly regulated as gestation progresses, suggesting that the transcellular pathway may be an alternative route for molecules to travel across the epithelium. In this study, we identified an extensive formation of a lysosomal system in the apical region of uterine epithelial cells in the highly secretory omphaloplacental region of the skink placenta in two species from the Pseudemoia genus. We suggest that this lysosomal system assists apocrine secretion by digesting large macromolecules into smaller particles, allowing more effective transport across the plasma membrane of uterine epithelial cells. We also demonstrate alkaline phosphatase (AP) activity along the apical plasma membrane of uterine epithelial cells in the omphaloplacental region of skink uterus, an enzyme usually associated with active transport in secretory cells. Apocrine secretion, an extensive lysosomal system and AP activity, offer strong evidence that macromolecules are transported across uterine epithelium of the omphaloplacenta. Our study is the first to provide histochemical evidence of macromolecular transport across this region of the placenta in two species of skinks from the genus with the most complex placenta described in Australia. J. Exp. Zool. (Mol. Dev. Evol.) 312B:817–826, 2009. © 2009 Wiley‐Liss, Inc.
Cinnoline chemistry. XI. The ultraviolet spectra of halogen substituted 4‐hydroxy‐ and 4‐mercaptocinnolines
Authors: Shoup Regitze R. , Castle Raymond N. 
Published: May 2009

AbstractThe ultraviolet spectra of a series of 4‐hydroxy‐ and 4‐mercaptocinnolines substituted with fluorine, chlorine or bromine in the 5‐, 6‐, 7‐ and 8‐position have been obtained in absolute methanol solution between 200 and 500 mμ. The spectra were used, to make structural assignments for the products of cyclization from mesoxalyl chloride, m‐fluoro‐and m‐bromophenylhydrazones.
Structure of products from reactions of phosphorus pentachloride with phenyl salicylate and 2‐hydroxybenzophenone; related compounds. p31 N.M.R. and chemical studies
Authors: Pinkus A. G. , Waldrep P. G. , Ma S. Y. 
Published: May 2009

AbstractThe compounds obtained from the reactions of phenyl salicylate and 2‐hydroxybenzo‐phenone with phosphorus pentachloride have been shown to have structures I A and II A, respectively, rather than alternative heterocyclic structures on the basis of the comparison of the P31 chemical shifts with appropriate reference compounds and additional chemical evidence. Compound I reacts with two equivalents of phenol in the presence of two equivalents of triethylamine to form mainly compound VIII (substitution on phosphorus). Structure VIII is confirmed via P31 n.m.r. and IR spectra and the fact that partial hydrolysis forms the same compound (VII) that is obtained from the reaction of compound III with phenol (only phosphorus substitution possible). A mechanism with initial reaction of phosphorus pentachloride (as tetrachlorophosphonium ion) on the phenolic hydroxyl is postulated on the basis of the available evidence. The P31 chemical shifts for compounds XIV A and XV A confirm these structures as heterocyclic in accord with previous chemical evidence. Structure XIV A is of historical importance as one of the first three cyclic structures ever published in the classical paper in which Couper announced his structural theory of organic chemistry.