bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of vibrational relaxation and molecular reorientation in liquids: a Raman spectroscopic study
Authors: Gomti Devi Th. 
Published: January 2010

AbstractThe vibrational relaxation and molecular reorientational processes in liquids have been studied in some carbonyl‐containing molecules using the acetonitrile (ACN) solvent. The vibrational and reorientational processes have been studied in correspondence with correlation times. The screening effect due to dielectric has been studied and the Onsager reaction field model has been tested. The study shows that repulsive types of intermolecular forces play an important role in complex systems. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis and Electrochemistry of Schiff Base Cobalt(III) Complexes and Their Catalytic Activity for Copolymerization of Epoxide and Carbon Dioxide
Authors: Zhuang Xiuli , Oyaizu Kenichi , Niu Yongsheng , Koshika Kenichiroh , Chen Xuesi , Nishide Hiroyuki 
Published: January 2010

AbstractA series of cobalt complexes with N,N,O,O‐tetradentate Schiff base ligands were prepared. All the complexes were characterized by spectroscopy and electrochemical methods. An X‐ray crystal structure analysis revealed that L1‐CoIII‐dnp was monomeric with a six‐coordinated central cobalt(III) atom in the solid state. The complexes were employed as catalysts for the alternating copolymerization of CO2 and racemic propylene oxide. End group analysis of the resulting polymer provided strong evidence for a monomer insertion mechanism for the propagation step. The catalytic activity was interpreted using the redox potential of cobalt(II/III) for the L‐CoIII‐dnp complexes, which offered a measure of the bond strength, or the degree of inertness of the axial ligand, to promote or suppress the monomer insertion.magnified image
Poly(lactic acid)/Aluminum Oxide Composites Fabricated by Sol‐Gel and Melt Compounding Processes
Authors: Yuzay Isinay E. , Auras Rafael , Selke Susan 
Published: January 2010

AbstractAluminum‐oxide‐coated PLA pellets, particles derived from aluminum oxide sol‐gel, and calcinated α‐Al2O3 powders were used to fabricate PLA/AlOx composites. The formation of aluminum oxide was confirmed by FTIR and EDS. SEM images suggested the melt compounding system provided a fairly homogeneous dispersion of AlOx particles in the PLA matrix. XRD analysis showed PLA and PLA/AlOx composites were both amorphous. The incorporation of AlOx particles did not alter the melting temperature of PLA. However, the shape and intensity of the melting endotherms was significantly changed, suggesting bimodal melting behavior. UV‐Vis transmission spectra suggested that PLA/AlOx composites may act as a better UV barrier than neat PLA.magnified image
Impact of Nanoscale Confinement on Crystal Orientation of Poly(ethylene oxide)
Authors: Wang Haopeng , Keum Jong K. , Hiltner Anne , Baer Eric 
Published: January 2010

AbstractUsing a layer‐multiplying coextrusion process to fabricate films with thousands of alternating polymer nanolayers, we report here a new crystalline morphology in confined polymer nanolayers and an abrupt transition in the crystallization habit. At higher temperatures, poly(ethylene oxide) crystallizes as large, in‐plane lamellae. A 5 °C change in the crystallization temperature produces an on‐edge lamellar orientation. The results point to a transition from heterogeneous nucleation to substrate‐assisted nucleation. This may be a general phenomenon that accounts for previously unexplained differences in the preferred chain alignment of confined polymer crystals.magnified image
Poly(2‐oxazoline)s as Smart Bioinspired Polymers
Authors: Schlaad Helmut , Diehl Christina , Gress Anja , Meyer Matthias , Demirel A. Levent , Nur Yusuf , Bertin Annabelle 
Published: January 2010

AbstractPoly(2‐alkyl‐2‐oxazoline)s can be regarded as pseudo‐peptides or bioinspired polymers, which are available through living/controlled cationic polymerization and polymer (“click”) modification procedures. Materials and solution properties may be adjusted via the nature of the side chain (hydrophilic‐hydrophobic, chiral, bio‐functional, etc.), opening the way to stimulus‐responsive materials and complex colloidal structures in aqueous environments. Herein, we give an overview over the macromolecular engineering of polyoxazolines, including the synthesis of biohybrids, and the “smart”/bioinspired aggregation behavior in solution.magnified image
Holes and Ledges Created by Multilayer Assembly on Polyelectrolyte Brushes: A Novel Route for the Three‐Dimensional Nanoscale Design of Surfaces
Authors: Llarena Irantzu , Ramos Jagoba J. Iturri , Donath Edwin , Moya Sergio E. 
Published: January 2010

AbstractThe layer‐by‐layer (LBL) assembly of poly(diallyldimethylammonium chloride) and poly(sodium styrene sulfonate) on poly(sulfo propyl methacrylate) brushes resulted in films with nanometer‐ and micrometer‐sized holes and ledges, observed by atomic force microscopy and scanning electron microscopy. Polyelectrolyte assembly was followed by the quartz microbalance technique. The formation of ledges and holes is explained by the interaction of the brush polymers with the incoming polyelectrolytes during the LBL assembly, inducing a spatially localized and self‐organized accumulation of the assembled polymers.magnified image
Crystallization‐Induced Phase Segregation Based on Double‐Crystalline Blends of Poly(3‐hexylthiophene) and Poly(ethylene glycol)s
Authors: Zhao Kui , Ding Zicheng , Xue Longjian , Han Yanchun 
Published: January 2010

AbstractCrystallization‐induced vertical stratified structures were constructed based on double‐crystalline poly(3‐hexylthiophene) (P3HT)/poly(ethylene glycol)s (PEG) systems at room temperature, in which the P3HT crystallinity and the mechanism were investigated. Vertical stratified microstructures with highly crystalline P3HT network on the surface were formed when depositing from marginal solvents, while lateral phase‐separated structures or low P3HT crystallinity were observed for good solvents. The morphological differences came from the solvent effect. In marginal solvents, p‐xylene and dichloromethane, P3HT large‐scale microcrystallites were generated in solution, which ensured the priority of P3HT crystalline sequence, and phase separation began in the liquid states. When the PEG matrix began to crystallize, great energy from which the second phase separation was induced drove P3HT crystallites to the surface, resulting in the formation of vertical stratified microstructures with highly crystalline P3HT network on the surface. The method, crystallization‐induced phase segregation of crystalline–crystalline blends in marginal solvent, provides a facile way to construct vertically stratified structures, in which P3HT highly crystalline network is favored.magnified image
Toward Tailor‐Made Biocide Materials Based on Poly(propylene)/Copper Nanoparticles
Authors: Palza Humberto , Gutiérrez Sebastian , Delgado Katherine , Salazar Oriana , Fuenzalida Victor , Avila Jonathan I. , Figueroa Guillermo , Quijada Raúl 
Published: January 2010

AbstractA set of poly(propylene) composites containing different amounts of copper nanoparticles (CNP) were prepared by the melt mixed method and their antimicrobial behavior was quantitatively studied. The time needed to reduce the bacteria to 50% dropped to half with only 1 v/v % of CNP, compared to the polymer without CNP. After 4 h, this composite killed more than 99.9% of the bacteria. The biocide kinetics can be controlled by the nanofiller content; composites with CNP concentrations higher than 10 v/v % eliminated 99% of the bacteria in less than 2 h. X‐ray photoelectron spectroscopy did not detect CNP at the surface, therefore the biocide behavior was attributed to copper in the bulk of the composite.magnified image
Initiation Kinetics in Free‐Radical Polymerization: Prediction of Thermodynamic and Kinetic Parameters Based on ab initio Calculations
Authors: Dossi Marco , Storti Giuseppe , Moscatelli Davide 
Published: January 2010

AbstractInitiation kinetics in free radical polymerization is investigated using density functional theory. Thermodynamic and kinetic parameters of the initiation reactions are predicted, and the role of the initiators in the polymerization process is evaluated. Methyl acrylate, methyl methacrylate, acrylonitrile, and styrene homo‐polymerizations with different initiators are studied. Reaction enthalpy and activation energy for each reaction between monomer and the radical fragments arising from the initiators have been determined. The initiation kinetic constants for all of these initiation reactions are evaluated and compared with both computational and experimental propagation kinetic constants of each monomer.magnified image
Development of Entanglements in a Fully Disentangled Polymer Melt
Authors: Vettorel Thomas , Kremer Kurt 
Published: January 2010

AbstractA long‐lived metastable “new melt” state of polymers has been recently reported, where monomers exhibit different mobilities due to an unusual distribution of entanglements. We study the relaxation of (fully disentangled) globules to the entangled state by means of computer simulations, and compare our data to the scenario of de Gennes' explosion upon melting. The entanglement length Ne is measured using the primitive path analysis method. The results show that in the case of relatively short chains (N ≈ 20Ne), the relaxation of the entanglement length is very fast compared to that of the chains' size which slows down as the chain length N exceeds the equilibrium value of Ne.magnified image
Has ‘lifetime prevalence’ reached the end of its life? An examination of the concept
Authors: Streiner David L. , Patten Scott B. , Anthony James C. , Cairney John 
Published: January 2010

AbstractMany cross‐sectional surveys in psychiatric epidemiology report estimates of lifetime prevalence, and the results consistently show a declining trend with age for such disorders as depression and anxiety. In a closed cohort with no mortality, lifetime prevalence should increase or remain constant with age. For mortality to account for declining lifetime prevalence, mortality rates in those with a disorder must exceed those without a disorder by a sufficient extent that more cases would be removed from the prevalence pool than are added by new cases, and this is unlikely to occur across most of the age range. We argue that the decline in lifetime prevalence with age cannot be explained by period or cohort effects or be due to a survivor effect, and are likely due to a variety of other factors, such as study design, forgetting, or reframing. Further, because lifetime prevalence is insensitive to changes in treatment effectiveness or demand for services, it is a parameter that should be dropped from the lexicon of psychiatric epidemiology. Copyright © 2009 John Wiley & Sons, Ltd.
Bilateral internal carotid artery occlusions in a pediatric patient with refractory acute myeloid leukemia
Authors: Fuh Beng , Lurito Joseph , Grossi Mauro , Daeschner Charles , Russo Suzanne 
Published: January 2010

AbstractThromboembolism is a well‐known complication of cancer including acute myeloid leukemia (AML) especially in patients with high myeloblast counts. However, spontaneous vaso‐occlusion in the main arteries is very rare especially in patients with low blast counts and no pre existing vasculopathy. We report the case of a 3‐year‐old male with refractory AML who developed spontaneous bilateral internal carotid artery occlusion with diffuse cerebral infarcts. Strokes are rarely secondary to spontaneous carotid artery thrombosis and few cases have been reported in the literature. Pediatr Blood Cancer 2010;54:770–772. © 2010 Wiley‐Liss, Inc.
Structures of human Bruton's tyrosine kinase in active and inactive conformations suggest a mechanism of activation for TEC family kinases
Authors: Marcotte Douglas J. , Liu Yu‐Ting , Arduini Robert M. , Hession Catherine A. , Miatkowski Konrad , Wildes Craig P. , Cullen Patrick F. , Hong Victor , Hopkins Brian T. , Mertsching Elisabeth , Jenkins Tracy J. , Romanowski Michael J. , Baker Darren P. , Silvian Laura F. 
Published: January 2010

AbstractBruton's tyrosine kinase (BTK), a member of the TEC family of kinases, plays a crucial role in B‐cell maturation and mast cell activation. Although the structures of the unphosphorylated mouse BTK kinase domain and the unphosphorylated and phosphorylated kinase domains of human ITK are known, understanding the kinase selectivity profiles of BTK inhibitors has been hampered by the lack of availability of a high resolution, ligand‐bound BTK structure. Here, we report the crystal structures of the human BTK kinase domain bound to either Dasatinib (BMS‐354825) at 1.9 Å resolution or to 4‐amino‐5‐(4‐phenoxyphenyl)‐7H‐pyrrolospyrimidin‐ 7‐yl‐cyclopentane at 1.6 Å resolution. This data provides information relevant to the development of small molecule inhibitors targeting BTK and the TEC family of nonreceptor tyrosine kinases. Analysis of the structural differences between the TEC and Src families of kinases near the Trp‐Glu‐Ile motif in the N‐terminal region of the kinase domain suggests a mechanism of regulation of the TEC family members.
Genetic encoding of non‐natural amino acids in Drosophila melanogaster Schneider 2 cells
Authors: Mukai Takahito , Wakiyama Motoaki , Sakamoto Kensaku , Yokoyama Shigeyuki 
Published: January 2010

AbstractInsect cells are useful for the high‐yield production of recombinant proteins including chemokines and membrane proteins. In this study, we developed an insect cell‐based system for incorporating non‐natural amino acids into proteins at specific sites. Three types of promoter systems were constructed, and their efficiencies were compared for the expression of the prokaryotic amber suppressor tRNATyr in Drosophila melanogaster Schneider 2 cells. When paired with a variant of Escherichia coli tyrosyl‐tRNA synthetase specific for 3‐iodo‐L‐tyrosine, the suppressor tRNA transcribed from the U6 promoter most efficiently incorporated the amino acid into proteins in the cells. The transient and stable introductions of these prokaryotic molecules into the insect cells were then compared in terms of the yield of proteins containing non‐natural amino acids, and the “transient” method generated a sevenfold higher yield. By this method, 4‐azido‐L‐phenylalanine was incorporated into human interleukin‐8 at a specific site. The yield of the azido‐containing IL‐8 was 1 μg/1 mL cell culture, and the recombinant protein was successfully labeled with a fluorescent probe by the Staudinger–Bertozzi reaction.
Electronic and optical properties of group IV two‐dimensional materials
Authors: Pulci O. , Gori P. , Marsili M. , Garbuio V. , Seitsonen A. P. , Bechstedt F. , Cricenti A. , Del Sole R. 
Published: January 2010

AbstractThe microscopic study of complex systems has reached a high level of accuracy that allows for a deep understanding of their structure, electronic properties, and optical spectra. The theoretical investigation of surfaces is nowadays routinely done within density functional theory, for ground state properties, and, with a larger computational load, within many‐body perturbation theory, for excited states properties. In this paper we present and discuss examples of calculations for group IV two‐dimensional systems such as a clean silicon surface, a tin–germanium interface, graphene, and graphane, pointing out the importance of a pertinent treatment of many‐body effects.
New insight into the photochromic mechanism of 1,3‐diphenyl‐4‐(4‐fluoro)benzal‐5‐pyrazolone N(4)‐phenyl semicarbazone
Authors: Yang Yinling , Wu Dongling , Jia Dianzeng , Liu Lang , Liu Anjie 
Published: January 2010

AbstractDensity functional theory (DFT) calculation has been carried out to investigate the photochromic mechanism of 1, 3‐diphenyl‐4‐(4‐fluoro)benzal‐5‐pyrazolone N(4)‐phenyl semicarbazone. The novel mechanism, proposed by us, has different reaction pathway between the forward and the reverse process. The energy barrier of the forward direction was calculated to be significantly larger than that of the reverse direction (30.35 kcal/mol to 9.88 kcal/mol), which confirms the experimental observation that the forward process needs irradiation of light while the reverse one will take place easily when heated. The solvent effect on the relative stabilities of those isomers that may involve in the reaction has also been investigated by applying the polarizable continuum model (PCM) of the self‐consistent reaction field theory. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Convergence and computational efficiency enhancements in the iterative solution of the G‐particle‐hole hypervirial equation
Authors: Alcoba D. R. , Tel L. M. , Pérez‐Romero E. , Valdemoro C. 
Published: January 2010

AbstractThe G‐particle‐hole hypervirial (GHV) equation has been recently reported (Valdemoro et al., Sixth International Congress of the International Society for Theoretical Chemical Physics Vancouver: Canada, 2008. Alcoba et al., Int J Quantum Chem 2009, 109, 3178; Valdemoro et al., Int J Quantum Chem 2009, 109, 2622). This equation is the newest member of the family of equations which can be obtained by applying a matrix‐contracting mapping (Valdemoro, An R Soc Esp Fís 1983, 79, 106; Valdemoro, Phys Rev A 1985, 31, 2114; Valdemoro, in Density Matrices and Density Functionals, Reidel: Dordrecht, 1987; p 275.) to the matrix representation in the N‐electron space of the Schrödinger, Liouville and hypervirial equations. The procedure that we have applied in order to solve the GHV equation exploits the stationary property of the hypervirials (Hirschfelder, J Chem Phys 1960, 33, 1462; Hirschfelder and Epstein, Phys Rev 1961, 123, 1495) and follows the general lines of Mazziotti's variational approach for solving the anti‐Hermitian contracted Schrödinger equation (ACSE) (Mazziotti, Phys Rev Lett 2006, 97, 143002; Mazziotti, Phys Rev A 2007, 75, 022505; Mazziotti, J Chem Phys 2007, 126, 184101). In this article, we report how the method's convergence has been significantly enhanced and how its computational scaling has been considerably reduced (in both floating‐point operations and storage). The results for a variety of atomic and molecular calculations confirming these methodological improvements are reported here. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Influence of substitution on the strength and nature of CH···N hydrogen bond in XCCH···NH3complexes
Authors: Roohi Hossein , Bagheri Sotoodeh 
Published: January 2010

AbstractThe effect of substitution on the strength and nature of CH···N hydrogen bond in XCCH···NH3(X = F, Cl, Br, OH, H, Me) and NCH···NH3complexes were investigated by quantum chemical calculations. Ab initio calculations were performed using MP2 method with a wide range of basis sets. With tacking into account the BSSE and ZPVE, the values of BEs decrease. Replacement of the nonparticipatory hydrogen atom of HCCH by the electronegative atoms (F, Cl, and Br), lead to the BEs increases. The BE corresponding to the replacement of the nonparticipatory hydrogen atom of HCCH by the OH and CH3groups decreases. A far greater enhancement of the interaction energy arises from replacement of HCCH by the more acidic HCN. The natural bond orbital analysis and the Bader's quantum theory of atoms in molecules were also used to elucidate the interaction characteristics of these complexes. The electrostatic nature of H‐bond interactions is predicted from QTAIM analysis. In addition, the relationship between the isotropic and anisotropic chemical shifts of the bridging hydrogen and binding energy of complexes as well as electron density at N···H BCPs were investigated. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Effect of magnetic field on diamagnetic susceptibility of two interacting electrons in a quantum dot
Authors: Radhakrishnan N. , Peter A. John 
Published: January 2010

AbstractWe have estimated the energy levels of the low‐lying states as a function of magnetic field when two electrons are introduced in a quantum dot (QD). Oscillator strength of interacting electrons for different magnetic field strengths has been calculated. There is no appreciable change in oscillator strength for stronger confinements for all the magnetic field strengths. We present the shift of diamagnetic susceptibility of a hydrogenic donor impurity in GaAs/Ga1−xAlxAs QD systems for the ground and low lying excited states. The effect of magnetic field on diamagnetic susceptibilities is estimated by two different methods and it has been found that values obtained from both the methods resemble each other. The diamagnetic shift is in good agreement with the other investigators. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Approximate solutions of the Schrödinger equation with the generalized Morse potential model including the centrifugal term
Authors: Zhang Lie‐Hui , Li Xiao‐Ping , Jia Chun‐Sheng 
Published: January 2010

AbstractBy using a new improved approximation scheme to deal with the centrifugal term, we solve approximately the Schrödinger equation with the generalized Morse potentials for the arbitrary angular momentum values. The bound state energy spectra and the unnormalized radial wave functions have been approximately obtained by using the basic concept of the supersymmetric shape invariance formalism and the function analysis method. The numerical experiments show that our approximate results are in better agreement with those obtained by using the numerical integration approach than the approximate results obtained by using the conventional approximation scheme to deal with the centrifugal term. We also calculate the rotational transition frequencies for HF molecule and compare them with the experimental data. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical study of the reactions of lanthanide ions (Ce+, Pr+) with CO2 in the gas phase
Authors: Wang Yong‐Cheng , Liu Hui‐Wen , Geng Zhi‐Yuan , Lv Ling‐Ling , Si Yu‐Bing , Wang Qing‐Yun , Wang Qiang , Cui Dan‐Dan 
Published: January 2010

AbstractThe mechanisms of the reaction of lanthanide ions (Ce+ and Pr+) with the carbon dioxide were investigated at the B3LYP level of theory. The crossing points (CPs) between the different potential energy surfaces (PESs) have been located by means of the intrinsic reaction coordinate approach used by Yoshizawa et al., and corresponding minimum energy crossing points (MECPs) that we obtained by the mathematical algorithm proposed by Harvey et al. has also been used. In addition, possible spin inversion processes are discussed by means of spin‐orbit coupling (SOC) calculations. The value of 61.68 cm−1 (for MECP1) and 69.17 cm−1 (for MECP2) for the SOC constants indicates that the spin crossing process in Ln+ + CO2 (1∑) reaction can be occurred efficiently because of the large SOC involved. And the O‐atom affinities (OA) testified that the argumentation is thermodynamically allowed. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Uranyl complexation by monodentate nitrogen donor ligands. A relativistic density functional study
Authors: Zakharieva Olga , Kremleva Alena , Krüger Sven , Rösch Notker 
Published: January 2010

AbstractTo examine the interaction of uranyl with nitrogen containing groups of humic substances, the model complexes [UO2(H2O)4LN]2+, LN = NH2CH3, N(CH3)3, and NC5H5 in aqueous solution were studied computationally with an all‐electron relativistic density functional method. Results are compared with the corresponding penta‐aqua complex of uranyl. Although pyridine coordinates with about the same strength as L = H2O, methylamine binds ∼10 kJ mol−1 stronger and trimethylamine ∼40 kJ mol−1 weaker than a fifth aqua ligand. Yet, each of these ligands LN donates about the same amount of charge to uranyl as L = H2O. UN bonds are ∼10 pm longer than the UO bonds of the aqua ligands. From the present model results, one does not expect that, when compared with carboxyl groups, monodentate N‐containing functional groups contribute significantly to uranyl complexation by humic substances. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011