bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organofunctionalized montmorillonite/epoxy nanocomposites: The effect of interlayer cation distribution on mechanical properties
Authors: Richardson Mickey C. , Kim Jaehyun , Ho Derek , Snyder Chad R. , D'souza Nandika A. , Holmes Gale A. 
Published: November 2010

AbstractThe present study indicates that a distribution of alkylammonium chain lengths in the interlayer of montmorillonite (MM) results in a greater degree of dispersion into an epoxy matrix (or possibly different polymer matrices) and improved ultimate tensile strengths. This hypothesis is supported by x‐ray diffraction (XRD) data from the modified MM clays, which clearly shows that an increase in d‐spacing does not result in an improvement in tensile strengths. Additional support is obtained from DSC analyses of the first and second heats of the treated clays which indicate that the C6 alkyl amine in a deposited (C18 + C6) alkyl ammonium mixture results in intercalation pathways for the epoxy resin. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Behavior of sandwich structures and spaced plates subjected to high‐velocity impacts
Authors: García‐Castillo Shirley K. , Buitrago Brenda L. , Barbero Enrique 
Published: November 2010

AbstractThis work evaluates the behavior of sandwich and spaced plates subjected to high‐velocity impacts. The sandwich structures were made of glass/polyester face‐sheet and a PVC foam core. The spaced plates were made of two plates of the same material of the sandwich face‐sheet at a distance equal to the core thickness. The residual velocity, the ballistic limit, and the damage area were selected to compare the response of both structures. The residual velocity and ballistic limit was very similar in both cases. Nevertheless, the damage area of sandwich structures and spaced plates differed due to the dissimilar properties between the sandwich core and the air inside of the spaced plates. An analytical model, based on energy criteria, was applied to estimate the residual velocity of the projectile, the absorbed energy by each face‐sheet, and the ballistic limit in the spaced plates. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Effect of modified carbon black on the UV/IR screening ability of poly(ethylene terephthalate) transparent films
Authors: Zhou Qilin , Zhang Yue , Li Qiuying , Wu Chifei 
Published: November 2010

AbstractThe mixed solution of poly (ethylene terephthalate) (PET)/carbon black (CB) and PET/modified CB (m‐CB) were coated on glass substrates to fabricate light screening films. m‐CB was prepared using a solid phase modification method through mechanical blending of CB and 2‐(2′‐Hydroxy‐5′‐methylphenyl)‐benzotriazole (UV‐P) in weight composition of 50 : 50. The results of dynamic light scattering (DLS), optical microscopy, and scanning electron microscopy (SEM) showed that the modification of CB obviously reduced the particle and aggregate sizes of CB, leading to better dispersion of m‐CB in PET films. Fourier transform infrared spectroscopy (FTIR) proved that UV‐P was grafted on CB after blending and changed the molecular structure of CB. Ultraviolet‐visible‐Infrared (UV‐vis‐IR) spectrophotometer tests showed that the UV/IR absorption property of the films improved obviously while the visible light transmittance reduced gradually with the increase of m‐CB content from 0.5 to 6 wt%. Differential scanning calorimeter (DSC) results showed the addition of 4 wt% m‐CB decreased the crystallinity of PET matrix, which effectively inhibited the destruction of the film transparency with the addition of more CB. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Dynamic proteomic analysis reveals diurnal homeostasis of key pathways in rice leaves
Authors: Wang Zizhang , Wang Tai 
Published: November 2010

AbstractDiurnal physiological acclimation regulated by a circadian system is an advantage for plant fitness. The circadian system is composed of a signal input, the clock and output pathways. Understanding the regulation mechanism of the output pathways remains a major challenge. Diurnal proteomic change reflects the state of circadian organization. We found the content of glucose, fructose, sucrose and starch diurnally changed in leaves of rice seedlings grown under a 12‐h light/12‐h dark condition with constant temperature. Dynamic proteomics analysis revealed 140 protein spots with diurnally changed levels at six times of the light/dark cycle; 132 spots were identified by MS, and 119 spots were of a single protein each with functional annotation. These proteins are involved in regulation of carbohydrate flow, redox, protein folding, nitrogen and protein metabolism, energy conversion, photorespiration and photosynthesis. Of these proteins, 81.5% were upregulated during the light phase, overlappingly, 41.2% showed behavior of circadian anticipation to dawn. Pattern analysis showed that the diurnal regulation involved pathways of allocation of carbohydrates between temporary reserves and consumption, maintenance of redox homeostasis, diurnal protein reassembly and nitrogen assimilation. These pathways reflect biochemical phenotypes of the circadian change linking the oscillator and circadian outputs.
The general form of nonlinear evolution equations integrable by matrix gelfand‐dikij spectral problem and their group‐theoretical and hamiltonian structures
Authors: Dubrovsky V. G. , Konopelchenko B. G. 
Published: November 2010

AbstractThe Gelfand‐Dikij spectral problem is considered in the AKNS‐technique framework. The general form of nonlinear evolution equations connected with matrix Gelfand‐Dikij spectral problem is found. The infinitedimensional abelian group of general Backlund transformations is constructed. The infinite family of Hamiltonian structures connected with the nonlinear equations under consideration is found.
Dynamical semigroups in the algebraic formulation of statistical mechanics
Authors: Majewski W. A. 
Published: November 2010

AbstractThe paper summarizing the recent results of the author is devoted to a detailed analysis of positive semigroups appearing in dynamical description of non‐equilibrium statistical mechanics. The first part of paper has a review character (this goes especially to sections 1 and 2). Novel aspects are contained in sections 3, 4 and 5. Section 4 contains the formulation and relatively complete discussion of detailed balance condition. In particular, the representation theorem for dynamical semigroups satisfying detailed balance is given. Section 5 contains new results from the theory of strongly and strictly positive semigroups.
Magnetic monopoles — a brief review
Authors: Bandyopadhyay B. K. , Gupta A. N. Sen 
Published: November 2010

AbstractMagnetic monopoles were first considered in detail by DIRAC in a 1931 paper, where he proved a charge‐quantization theorem. The experimental searches which followed proved fruitless. Recently there has been a rapid increase in theoretical and experimental work in this field. A highly controversial detection claim was made by PRICE, SHIRK, OSBORNE and PINSKY in 1975. Report has also come of a possible monopole detection at Stanford university in February, 1982.
The thermodynamical history of the universe
Authors: Marx George 
Published: November 2010

AbstractA predestrian walk is offered in the early universe. It is argued that the universe has departed from its original thermal equilibrium as a consequence of its mechanical instability. This transient deviation from the state of maximum entropy has made the creation of protons and galaxies possible. It is shown that several puzzling astrophysical phenomena can be explained by assuming a nonvanishing rest mass for the heaviest stable neutrino in the region of 30 eV.
Theoretical analysis of quantum electrodynamics
Authors: Manoukian Edward B. 
Published: November 2010

AbstractA study is carried out of some of the important developments made in quantum electrodynamics (QED) during this past decade. Basic problems and recent attempts are considered which are expected to be of importance not only for further developments in QED, but also to our further understanding of quantum field theory, in general and of its unique role played in describing the dynamics of elementary particles.
Physical charged sectors in quantum electrodynamics. I. Infra‐red asymptotics
Authors: d'Emilio Emilio , Mintchev Mihail 
Published: November 2010

AbstractThe infra‐red asymptotic behaviour of the physical charged sectors of quantum electrodynamics is investigated. Properly defined locally gauge‐invariant charged fields (nonlocal with respect to the electromagnetic field and different, in nature, from the string variables) are found to have vanishing infra‐red anomalous dimension. The corresponding Lehman‐Symanzik‐Zimmermann limits admit a Fock representation and the Poincaré group is implementable on the asymptotic physical Hubert spaces. The scattering matrix is the well known one, but for the fact it admits a representation in which the usual logarithms of the “vanishing photon mass” are substituted by the logarithms of a finite mass scale. The latter is furtherly replaced by the finite energy resolution of the measuring apparatus when cross sections are computed according to the prescription of Bloch and Nordsieck.
Dynamic communication between androgen and coactivator: Mutually induced conformational perturbations in androgen receptor ligand‐binding domain
Authors: Xu Xue , Yang Wei , Wang Xia , Li Yan , Wang Yonghua , Ai Chunzhi 
Published: November 2010

AbstractThe transcriptional activity of androgen receptor (AR) is regulated by the sequential binding of various ligands (e.g., dihydrotestosterone, DHT) and coactivators (e.g., SRC/p160) to the AR ligand binding domain (LBD) (Askew et al., J Biol Chem 2007;282:25801–25816, Lee and Chang, Cell Mol Life Sci 2003;60:1613–1622). However, the synergism between the recruitments of coactivator (SRC 2–3) and ligand (such as DHT) to AR at atomic level remains unclear. Thus, in this work, extensive explicit‐solvent molecular dynamics (MD) simulations on four independent trajectories, that is, AR‐apo (unbound), DHT·AR, AR·SRC, and DHT·AR·SRC, are performed to investigate the potential communications between the two events in the AR transcriptional process. The MD simulations, analysis of the dynamical cross‐correlation maps, comparisons of the binding energy, and thermodynamic analysis reveal a definite structural and functional link between Activation Function‐2 (AF‐2) surface and the ligand binding site influenced by the binding of ligand and coactivator to the LBD: (I) The DHT binding can increase the LBD volume to 753.0 Å3 from its compact ligand‐free state (372.1 Å3), resulting in a group of helices (1, 2, 8, and loop 2′) to move outward and exert added traction on the ligand binding pathway, which subsequently leads to rearrange the AF‐2 region to well recruit the SRC; (II) Similarly, the SRC recruitment is also found to facilitate the ligand binding through transmitting a concomitant push‐pull effort from the AF‐2 surface to the DHT binding site, leading to the opening of entrance to the LBD formed by Val684, Met745, and Arg752, increase of the volume of binding pocket (896.4 Å3) and stabilization of the dynamic structure of the LBD. These results, in a dynamic form, initially show a bidirectional structural and functional relay between the bound DHT and SRC that establishes AR functional potency. Proteins 2011. © 2011 Wiley‐Liss, Inc.
On the evolutionary origin of the chaperonins
Authors: Dekker Carien , Willison Keith R. , Taylor William R. 
Published: November 2010

AbstractAn analysis of the apical domain of the Group‐I and Group‐II chaperonins shows that they have structural similarities to two different protein folds: a “swivel‐domain” phosphotransferase and a thioredoxin‐like peroxiredoxin. There is no significant sequence similarity that supports either similarity and the degree of similarity based on structure is comparable but weak for both relationships. Based on possible evolutionary transitions, we deduced that a phosphotransferase origin would require both a large insertion and deletion of structure whereas a peroxiredoxin origin requires only a peripheral rearrangement, similar to an internal domain‐swap. We postulate that this change could have been triggered by the insertion of a peroxiredoxin into the ATPase domain that led to the modern chaperonin domain arrangement. The peroxidoxin fold is the most highly embellished member of the thioredoxin super‐family and the insertion event may have “overloaded” the core, leading to a rearrangement. A peroxiredoxin origin for the domain also provides a functional explanation, as the peroxiredoxins can act as chaperones when they adopt a multimeric ring complex, similar to the chaperonin subunit configuration. In addition, several of the GroEL apical domain hydrophobic residues which interact with the unfolded protein are located in a position that corresponds to the protein substrate binding region of the peroxiredoxin fold. We suggest that the origin of the ur‐chaperonin from a thioredoxin/peroxiredoxin fold might also account for the number of thioredoxin‐fold containing proteins that interact with chaperonins, such as tubulin and phosducin‐like proteins. Proteins 2011. © 2010 Wiley‐Liss, Inc.
Influenza virus H5N1 hemagglutinin (HA) T‐cell epitope conjugates: design, synthesis and immunogenicity
Authors: Skarlas Theodore , Zevgiti Stella , Droebner Karoline , Panou‐Pomonis Eugenia , Planz Oliver , Sakarellos‐Daitsiotis Maria 
Published: November 2010

AbstractThe influenza virus, major surface glycoprotein hemagglutinin (HA) is one of the principal targets for the development of protective immunity. Aiming at contributing to the development of a vaccine that remains the first choice for prophylactic intervention, a reconstituted model of HA, mimicking its antigenic properties was designed, synthesized and tested in mice for the induction of protective immunity. Four helper T lymphocyte [HTL (T1, T3, T7 and T8)] and four cytotoxic lymphocyte [CTL (T2, T4, T5 and T6)] epitopes were coupled in two copies each to an artificial carrier, SOC4, which was formed by the repeating tripeptide Lys‐Aib‐Gly. The helical conformation of the SOC4‐conjugates preserves the initial topology of the attached epitopes, which is critical for their immunogenic properties. Survival of immunized animals, ranged from 30 to 50%, points out the induction of protective immunity by using the SOC4‐conjugates. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Ferromagnetic and metallic properties of the semihydrogenated GaN sheet
Authors: Xiao Wen‐Zhi , Wang Ling‐Ling , Xu Liang , Wan Qing , Pan An‐Lian , Deng Hui‐Qiu 
Published: December 2010

AbstractBased on first‐principles spin‐polarized density functional theory (DFT) calculations, the geometric, electronic structures, and magnetic properties of semihydrogenated gallium nitride (GaN) sheet are investigated. The HGaN conformation exhibits ferromagnetic (FM) ground state with a magnetic moment of about 1.0 µB per unit cell. The ferromagnetism is mainly attributed to the decrease in the charge transfer from Ga to N atoms after hydrogenated, which leads to the partial occupancy of the N‐2pz orbitals. The half‐boat conformation is predicted to be the most stable structure with an indirect bandgap of 2.34 eV. While the GaNH conformation shows metallic behavior without magnetism.
Competing energy scales in high‐temperature superconductors: Ultrafast pump–probe studies
Authors: Chia Elbert E. M. , Zhu Jian‐Xin , Talbayev D. , Taylor A. J. 
Published: November 2010

AbstractWe present a review of photoexcited quasiparticle dynamics of cuprate and pnictide high‐temperature superconductors in regimes (temperature, doping) where different phases such as superconductivity, spin‐density‐wave (SDW) and pseudogap phases coexist or compete with one another. We start with the overdoped cuprate superconductor Y1–xCax Ba2Cu3O7–δ, where the superconducting gap and pseudogap coexist in the superconducting state. In another cuprate Tl2Ba2Ca2Cu3Oy, we ob‐ serve a competition between SDW and superconducting orders deep in the superconducting state. Finally, in the underdoped iron pnictide superconductor (Ba,K)Fe2As2, SDW order forms at 85 K, followed by superconductivity at 28 K. We also find the emergence of a normal‐state order that suppresses SDW at a temperature T * ∼ 60 K and argue that this normal‐state order is a precursor to superconductivity. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Applications of automatic differentiation to the time‐dependent Schrödinger equation
Authors: Chou Chia‐Chun , Wyatt Robert E. 
Published: November 2010

AbstractA new approach based upon the Taylor series method is proposed for propagating solutions of the time‐dependent Schrödinger equation. Replacing the spatial derivative of the wave function with finite difference formulas, we derive a recursive formula for the evaluation of Taylor coefficients. The automatic differentiation technique is used to recursively calculate the required Taylor coefficients. We also develop an implicit scheme for the recursive evaluation of these coefficients. We then advance the solution in time using a Taylor series expansion. Excellent computational results are obtained when this method is applied to a one‐dimensional reflectionless potential and a two‐dimensional barrier transmission problem. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Fragmentation investigation of brassinosteroid compounds by ion trap and quadrupole time‐of‐flight mass spectrometry
Authors: Huo Feifeng , Bai Yu , Liu Huwei 
Published: November 2010

AbstractThe fragmentation mechanisms of three types of brassinosteroids (BRs), 23,24‐tris‐epicastasterone, epicastasterone, tris–epicastasterone, 24‐epibrassinolide and 6‐deoxo‐24‐epicastasterone, have been extensively investigated by tandem mass spectrometry (MSn, n = 1, 2, 3, 4, 5) with the assistance of high mass accuracy quadrupole time‐of‐flight mass spectrometry (QToF MS). The electrospray ionization (ESI) mass spectrometric fragmentation pathways of these five BRs were comprehensively elucidated for the first time. Cleavages of side chains, neutral losses of water or other molecules and opening of a ring induce the main fragmentation patterns. The results from the present study can potentially afford important guidance for the structural elucidation of different BRs and provide some fundamental data for metabolomic analysis of BRs. Copyright © 2010 John Wiley & Sons, Ltd.
Multiple imputation using chained equations: Issues and guidance for practice
Authors: White Ian R. , Royston Patrick , Wood Angela M. 
Published: November 2010

AbstractMultiple imputation by chained equations is a flexible and practical approach to handling missing data. We describe the principles of the method and show how to impute categorical and quantitative variables, including skewed variables. We give guidance on how to specify the imputation model and how many imputations are needed. We describe the practical analysis of multiply imputed data, including model building and model checking. We stress the limitations of the method and discuss the possible pitfalls. We illustrate the ideas using a data set in mental health, giving Stata code fragments. Copyright © 2010 John Wiley & Sons, Ltd.
Where can capabilities come from? network ties and capability acquisition in business groups
Authors: Mahmood Ishtiaq P. , Zhu Hongjin , Zajac Edward J. 
Published: December 2010

AbstractWhile strategy researchers have devoted considerable attention to the role of firm‐specific capabilities in the pursuit of competitive advantage, less attention has been directed at how firms obtain these capabilities from outside their boundaries. In this study, we examine how firms' multiplex network ties in business groups represent one important source of capability acquisition. Our focus allows us to go beyond the traditional focus on network structure and offer a novel contingency model that specifies how different types of network ties (e.g., buyer‐supplier, equity, and director), individually and in complementary combination, will differentially affect the process of R&D capability acquisition. We also offer an original analysis of how other aspects of network structure (i.e., network density) in business groups affect the efficacy of network ties on R&D capability. Empirically, we provide an original contribution to the capabilities literature by utilizing a stochastic frontier estimation to rigorously measure firm capabilities, and we demonstrate the value of this approach using longitudinal data on business groups in emerging economies. We close by discussing the implications of our supportive results for future research on firm capabilities, organizational networks, and business groups. Copyright © 2010 John Wiley & Sons, Ltd.
Compatibility of the endurance time method with codified seismic analysis approaches on three‐dimensional analysis of steel frames
Authors: Valamanesh V. , Estekanchi H. E. 
Published: December 2010

SUMMARYThe endurance time (ET) method is a time history‐based dynamic pushover analysis procedure that utilizes special intensifying acceleration functions for estimating the seismic performance of structures at different excitation levels. One of the potential applications of the ET method is in the three‐dimensional analysis of buildings considering multidirectional excitation. In this paper, a procedure for multi‐component analysis by the ET method has been developed. Several steel moment frames with heights from 9.6 to 48 m were designed according to the Iranian National Building Code. By applying the proposed algorithm for three‐dimensional analysis of structures by the ET method, these frames were analyzed, and results have been compared with static, response spectrum and response history methods considering typical code recommendations. Results show that for all studied models, even when irregularity and height of structure increase, the ET method estimates the seismic response of steel frames with reasonable accuracy compared with other investigated approaches. Copyright © 2010 John Wiley & Sons, Ltd.
Enantioselective epoxidation of electron‐deficient olefins: an organocatalytic approach
Authors: Weiß Katharina M. , Tsogoeva Svetlana B. 
Published: November 2010

AbstractVersatile synthetic intermediates—α,β‐epoxyketones and α,β‐epoxyaldehydes—can be obtained through asymmetric organocatalytic epoxidation of α,β‐unsaturated ketones and aldehydes. This Review focuses on some recent advances in these epoxidation reactions with respect to scope and limitations with polyamino acids, phase‐transfer catalysts (PTCs), amines, and guanidines as chiral organocatalysts. Furthermore, recent results obtained with chiral peroxides are discussed. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.201000006