bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonisothermal crystallization behaviors and conductive properties of PEO‐based solid polymer electrolytes containing yttrium oxide nanoparticles
Authors: Liang Guijie , Xu Jie , Xu Weilin , Shen Xiaolin , Bai Zhikui , Yao Mu 
Published: July 2011

AbstractLithium solid polymer electrolytes (SPE) composed of polyethylene oxide (PEO) and yttrium oxide (Y2O3) nanoparticles were prepared. The influence of the Y2O3 nanoparticles on the non‐isothermal crystallization behaviors, crystal structure, and conductive properties of the SPE were investigated. The peak temperature, crystallinity, and crystallization half‐time (t1/2) of the SPE were strongly dependent on the concentration of Y2O3 and the cooling rate. The non‐isothermal crystallization data were analyzed by the modified Avrami model, which successfully described the nonisothermal crystallization process of the SPE. The Avrami exponents suggested that the Y2O3 nanoparticles significantly affected both the nucleation mechanism and crystal growth of the PEO matrix. The nucleating and crystallization activation energies (ψ and Ec) estimated with different theories indicated that the Y2O3 nanoparticles were inclined to serve as heterogeneous nucleating agents to benefit the crystallization at lower concentration whereas as physical hindrance to inhibit the crystal growth at relatively higher concentration. The maximum conductivity (σ) of 5.95 × 10−5 S cm−1 at room temperature for the SPE was obtained at the Y2O3 weight ratio of 0.10. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Extruded cylindrical strands: Mechanical properties correlated with the formation of biodegradable films through blown extrusion
Authors: Nobrega Marcelo Medre , Bona Evandro , Muller Carmen Maria Olivera , Yamashita Fabio 
Published: July 2011

AbstractThe objective of this study was to determine the mechanical and viscoelastic properties of extruded cylindrical strands from biodegradable polymer blends and to verify the correlation of the blend properties with their capacity to form films in the blown extrusion process. The production of biodegradable films would only occur if the extruded strands showed adequate characteristics. The strands were produced by extrusion with blends containing starch, glycerol, and fatty acids (caproic, lauric, and stearic). These blends were compared with a standard formulation containing poly(butylene adipate‐co‐terephthalate) (PBAT), a biodegradable polymer. From the mechanical tension tests, the extruded strands containing fatty acids differed significantly from the standard one, it was not clear the possibility to establish a comparison between the mechanical properties of the extruded strands and the formation of films. The rheological tests indicated that the polymer blends presented the desired viscoelastic characteristics for the film formation by blown extrusion. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
A quantum chemistry study of the free‐radical copolymerization propagation kinetics of styrene and 2‐hydroxyethyl acrylate
Authors: Dossi Marco , Storti Giuseppe , Moscatelli Davide 
Published: July 2011

AbstractSeveral difficulties are reported in literature about the experimental analysis of polymerizations involving 2‐hydroxyethyl acrylate (HEA), mainly due to transfer reactions that characterize the system. In particular, major problems are emerged in the study of free radical copolymerization kinetics of HEA. In this work, free‐radical copolymerization propagation kinetics of HEA and styrene (ST) are investigated through a computational approach based on density functional theory. Monomer reactivity ratios for HEA/ST copolymerization are calculated at 50°C and 125°C, obtaining values that exhibit a weak dependence on temperature. In particular, HEA reactivity ratio, rHEA, equal to 0.14 and ST reactivity ratio, rST, equal to 0.31 at 50°C, whereas rHEA = 0.17 and rST = 0.29 at 125°C. Moreover, the reliability of such parameters has been tested by analyzing copolymer composition data as a function of monomer feed composition, at the same temperatures indicated above. Experimental values proposed in literature are well predicted by the terminal copolymerization model using the kinetic parameters computationally determined. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Synthesis and characterization of styrene modified vinylester resin‐clay nanocomposites
Authors: Abdelwahab Mohamed , Agag Tarek , Akelah Ahmed , Takeichi Tsutomu 
Published: July 2011

AbstractThe influence of styrene as a reactive diluent on the morphology of vinylester resin‐clay hybrids has been studied. Two mixtures of diglycidylether of bisphenol‐A diacrylate as vinyl ester resin and styrene (20 and 40%) were prepared. Various weight ratios of styryl‐functional organoclay were added to vinylester resin/styrene mixture, followed by polymerization of the mixture up to 160°C. The morphology of the hybrids studied by X‐ray diffraction and Scanning Electron Microscope revealed that the dispersion of organoclay increased with the increase of styrene content. The inclusion of styrene to the system gave ordered intercalated nanocomposites. The surface hardness of the hybrid films decreased with adding a higher content of styrene. Thermogravimetric analysis indicates that clay is effective in promoting char‐forming reaction of vinylester resin/styrene clay nanocomposites. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers
Proteomic analysis of larval integument, trachea and adult scale from the silkworm, Bombyx mori
Authors: Fu Qiang , Li Peng , Xu Yunmin , Zhang Sai , Jia Ling , Zha Xingfu , Xiang Zhonghuai , He Ningjia 
Published: July 2011

AbstractMultidimensional LC‐tandem MS was used to investigate the protein compositions of three tissues of silkworm, Bombyx mori. A total of 162, 259, and 175 peptides from silkworm larval integument and trachea, and adult scale obtained by database search were matched to 48, 51, and 40 proteins, respectively. Forty‐one cuticular proteins were identified from three tissues and covered all five cuticular protein families of silkworm. In the adult scale, all seven cuticular proteins were identified for the first time in the final pellet after SDS extraction. The majority of cuticular proteins were found in each tissue differentially, suggesting that tissue‐specific cuticular proteins were involved in the building of the specialized tissues. Seventy‐three non‐cuticular proteins were also identified in this analysis mainly including muscular proteins, proteinases, inhibitors, transport proteins, and redox‐related proteins.
Modulation of septin and molecular motor recruitment in the microtubule environment of the Taxol‐resistant human breast cancer cell line MDA‐MB‐231
Authors: Froidevaux‐Klipfel Laurence , Poirier Florence , Boursier Céline , Crépin Ronan , Poüs Christian , Baudin Bruno , Baillet Anita 
Published: July 2011

AbstractCell resistance to low doses of paclitaxel (Taxol) involves a modulation of microtubule (MT) dynamics. We applied a proteomic approach based on 2‐DE coupled with MS to identify changes in the MT environment of Taxol‐resistant breast cancer cells. Having established a proteomic pattern of the microtubular proteins extracted from MDA‐MB‐231 cells, we verified by Western blotting that in resistant cells, α‐ and β‐tubulins (more specifically the βIII and βIV isotypes) increased. Interestingly, four septins (SEPT2, 8, 9 and 11), which are GTPases involved in cytokinesis and in MT/actin cytoskeleton organization, were overexpressed and enriched in the MT environment of Taxol‐resistant cells compared to their sensitive counterpart. Changes in the MT proteome of resistant cells also comprised increased kinesin‐1 heavy chain expression and recruitment on MTs while dynein light chain‐1 was downregulated. Modulation of motor protein recruitment around MTs might reflect their important role in controlling MT dynamics via the organization of signaling pathways. The identification of proteins previously unknown to be linked to taxane‐resistance could also be valuable to identify new biological markers of resistance.
Differential expression profile of membrane proteins in zebrafish (Danio rerio) brain exposed to methyl parathion
Authors: Huang Qing‐Yu , Huang He‐Qing 
Published: July 2011

AbstractMethyl parathion (MP) is a widely used organophosphorus pesticide, which has been related to a broad spectrum of toxic effects on environmental organisms. The present study investigated the changes in the protein profile of enriched membrane fraction from zebrafish (Danio rerio) brain exposed to three concentrations (0.5, 1 and 2 mg/L) of MP. 2‐DE revealed that the abundance of 21 protein spots was significantly changed by MP stress. By matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry and database search, 16 protein spots were identified as membrane proteins, among which 8 were down‐regulated, while 8 were up‐regulated. These proteins are mainly involved in oxidative stress response, signal transduction, metabolism, protein synthesis and degradation, neuroplasticity and regeneration as well as synaptic transmission. These results may aid our understanding of the mechanism of MP‐induced neurotoxicity and provide the possibility of the establishment of candidate biomarkers of MP.
Identifying differentially expressed genes in cancer patients using a non‐parameter Ising model
Authors: Li Xumeng , Feltus Frank A. , Sun Xiaoqian , Wang James Z. , Luo Feng 
Published: July 2011

AbstractIdentification of genes and pathways involved in diseases and physiological conditions is a major task in systems biology. In this study, we developed a novel non‐parameter Ising model to integrate protein–protein interaction network and microarray data for identifying differentially expressed (DE) genes. We also proposed a simulated annealing algorithm to find the optimal configuration of the Ising model. The Ising model was applied to two breast cancer microarray data sets. The results showed that more cancer‐related DE sub‐networks and genes were identified by the Ising model than those by the Markov random field model. Furthermore, cross‐validation experiments showed that DE genes identified by Ising model can improve classification performance compared with DE genes identified by Markov random field model.
QSE: A new 3‐D solvent exposure measure for the analysis of protein structure
Authors: Li Peipei , Pok Gouchol , Jung Kwang Su , Shon Ho Sun , Ryu Keun Ho 
Published: July 2011

AbstractSolvent exposure of amino acids measures how deep residues are buried in tertiary structure of proteins, and hence it provides important information for analyzing and predicting protein structure and functions. Existing methods of calculating solvent exposure such as accessible surface area, relative accessible surface area, residue depth, contact number, and half‐sphere exposure still have some limitations. In this article, we propose a novel solvent exposure measure named quadrant‐sphere exposure (QSE) based on eight quadrants derived from spherical neighborhood. The proposed measure forms a microenvironment around Cα atom as a sphere with a radius of 13 Å, and subdivides it into eight quadrants according to a rectangular coordinate system constructed based on geometric relationships of backbone atoms. The number of neighboring Cα atoms whose labels are the same is given as the QSE value of the center Cα atom at hand. As evidenced by histograms that show very different distributions for different structure configurations, the proposed measure captures local properties that are characteristic for a residue's eight‐directional neighborhood within a sphere. Compared with other measures, QSE provides a different view of solvent exposure, and provides information that is specific for different tertiary structure. As the experimental results show, QSE measure can potentially be used in protein structure analysis and predictions.
Replacing the Equations of Fano and Fisher for Cased Charge Blast Equivalence – I Ductile Casings
Authors: Hutchinson Mike D. 
Published: July 2011

AbstractThe initial velocity of casing fragments from bombs, shells etc. was first calculated by R. W. Gurney in 1943 [1]. Subsequent to this derivation by Gurney, which was based on a reasonable simplification of the case and gas dynamics, his wartime co‐worker, U. Fano [2], claimed to have calculated the proportion of kinetic energy remaining with the explosive gases following energy partition with the casing. This paper shows that both Fano’s equation for cased charge blast equivalence and a further derivation by Fisher in 1953 [3], based on Fano’s, are in fact inconsistent with Gurney’s reasonable physical model. Neither of these two reports has ever been the subject of independent peer‐review, despite having been extensively cited. This paper identifies the error made by Fano and copied by Fisher and draws attention to an alternate equation recently published by the author which gives similar predictions to that of Fisher, while being consistent with Gurney’s original derivation. Also, this paper establishes for the first time that the use of such equations for cased charge blast impulse equivalence is valid.
Determination of protein fold class from Raman or Raman optical activity spectra using random forests
Authors: Kinalwa Myra , Blanch Ewan W. , Doig Andrew J. 
Published: July 2011

AbstractKnowledge of the fold class of a protein is valuable because fold class gives an indication of protein function and evolution. Fold class can be accurately determined from a crystal structure or NMR structure, though these methods are expensive, time‐consuming, and inapplicable to all proteins. In contrast, vibrational spectra [infra‐red, Raman, or Raman optical activity (ROA)] are rapidly obtained for proteins under wide range of biological molecules under diverse experimental and physiological conditions. Here, we show that the fold class of a protein can be determined from Raman or ROA spectra by converting a spectrum into data of 10 cm−1 bin widths and applying the random forest machine learning algorithm. Spectral data from 605 and 1785 cm−1 were analyzed, as well as the amide I, II, and III regions in isolation and in combination. ROA amide II and III data gave the best performance, with 33 of 44 proteins assigned to one of the correct four top‐level structural classification of proteins (SCOP) fold class (all α, all β, α and β, and disordered). The method also shows which spectral regions are most valuable in assigning fold class.
Structural analysis of CPF_2247, a novel α‐amylase from Clostridium perfringens
Authors: Ficko‐Blean Elizabeth , Stuart Christopher P. , Boraston Alisdair B. 
Published: July 2011

AbstractCPF_2247 from Clostridium perfringens ATCC 13124 was identified as a putative carbohydrate‐active enzyme by its low sequence identity to endo‐β‐1,4‐glucanases belonging to family 8 of the glycoside hydrolase classification. The X‐ray crystal structure of CPF_2247 determined to 2.0 Å resolution by single‐wavelength anomalous dispersion using seleno‐methionine‐substituted protein revealed an (α/α)6 barrel fold. A large cleft on the surface of the protein contains residues that are structurally conserved with key elements of the catalytic machinery in clan GH‐M glycoside hydrolases. Assessment of CPF_2247 as a carbohydrate‐active enzyme disclosed α‐glucanase activity on amylose, glycogen, and malto‐oligosaccharides. Proteins 2011;. © 2011 Wiley‐Liss, Inc.
Three ways in, one way out: Water dynamics in the trans‐membrane domains of the inner membrane translocase AcrB
Authors: Fischer Nadine , Kandt Christian 
Published: July 2011

AbstractPowered by proton‐motive force, the inner membrane translocase AcrB is the engine of the AcrAB‐TolC efflux pump in Escherichia coli. As proton conduction in proteins occurs along hydrogen‐bonded networks of polar residues and water molecules, knowledge of the protein‐internal water distribution and water‐interacting residues allows drawing conclusions to possible pathways of proton conduction. Here, we report a series of 6× 50 ns independent molecular dynamics simulations of asymmetric AcrB embedded in a phospholipid/water environment. Simulating each monomer in its proposed protonation state, we calculated for each trans‐membrane domain the average water distribution, identified residues interacting with these waters and quantified each residue's frequency of water hydrogen bond contact. Combining this information we find three possible routes of proton transfer connecting a continuously hydrated region of known key residues in the TMD interior to bulk water by one cytoplasmic and up to three periplasm water channels in monomer B and A. We find that water access of the trans‐membrane domains is regulated by four groups of residues in a combination of side chain re‐orientations and shifts of trans‐membrane helices. Our findings support a proton release event via Arg971 during the C intermediate or in the transition to A, and proton uptake occurring in the A or B state or during a so far unknown intermediate in between B and C where cytoplasmic water access is still possible. Our simulations suggest experimentally testable hypotheses, which have not been investigated so far. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Prechemistry versus preorganization in DNA replication fidelity
Authors: Ram Prasad B. , Warshel Arieh 
Published: July 2011

AbstractThe molecular origin of nucleotide insertion catalysis and fidelity of DNA polymerases is explored by means of computational simulations. Special attention is paid to the examination of the validity of proposals that invoke prechemistry effects, checkpoints concepts, and dynamical effects. The simulations reproduce the observed fidelity in Pol β, starting with the relevant observed X‐ray structures of the complex with the right (R) and wrong (W) nucleotides. The generation of free energy surfaces for the R and W systems also allowed us to analyze different proposals about the origin of the fidelity and to reach several important conclusions. It is found that the potential of mean force (PMF) obtained by proper sampling does not support QM/MM‐based proposals of a large barrier before the prechemistry state. Furthermore, examination of dynamical proposals by the renormalization approach indicates that the motions from open to close configurations do not contribute to catalysis or fidelity. Finally we discuss and analyze the induced fit concept and show that, despite its importance, it does not explain fidelity. That is, the fidelity is apparently due to the change in the preorganization of the chemical site, as a result of the relaxation of the binding site upon binding of the incorrect nucleotide. Finally and importantly, since the issue is the barrier associated with the enzyme–substrate (ES)/DNA complex at the chemical transition state and not the path to this complex formation (unless this path involves rate determining steps), it is also not useful to invoke checkpoints while discussing fidelity. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Integrate plant reliability efforts with mechanical integrity
Authors: Vaughen Bruce K. , Nagel John F. , Allen Matthew J. 
Published: July 2011

AbstractMaintenance ensures the reliability of the equipment to meet operation's demands. Operations ensure the production of sufficient and high quality product. Engineering designs and installs equipment that minimizes risk. Safety ensures that the engineering and administrative controls are in place to minimize that risk. This article presents a concept that combines these reliability and safety efforts, such that the maintenance, operations, engineering and safety groups speak the same language to minimize the overall business risk.This proposed approach combines existing plant reliability efforts with several Process Safety Management elements. The basic steps include identifying safety‐critical equipment, ensuring accurate and up‐to‐date Process Safety Information (PSI), establishing the mechanical integrity (MI) Program, establishing Planned Maintenance (PM) programs, and creating equipment‐specific maintenance procedures.The resultant mechanical integrity quality assurance (MI QA) program combines equipment reliability and operational integrity efforts to ensure that the equipment is properly designed (via PSI), fabricated as designed (via PSI and MI), and installed as designed (via Pre‐Start‐up Safety Reviews). The MI QA program also ensures that the equipment is operated and maintained as designed by trained personnel. Some benefits include being able to: (1) share and document best MI and PM practices between different sites; (2) focus limited PM‐related resources on the process safety‐critical equipment; and (3) help monitor the essential reliability efforts to ensure continued safe operation. © 2011 American Institute of Chemical Engineers Process Saf Prog, 2011
Staggered InGaAs/GaAsP strained layer superlattices for use in optical devices
Authors: Colter P. C. , Carlin C. Z. , Samberg J. P. , Bradshaw G. K. , Bedair S. M. 
Published: July 2011

AbstractStrained layer superlattice (SLS) structures lattice matched to GaAs, such as InGaAs/GaAsP, use thin films to meet both the strain balance and critical layer thickness (CLT) conditions. Optical absorption in the InGaAs layers will be shifted to higher energies relative to thick films due to both the quantum size effect (QSE) and compressive strain, which is an undesirable restriction. We report on a new concept for a strain balance superlattice that will allow for thicker InGaAs films and reduce the cutoff energy. The staggered strain balanced superlattice structure can improve the performance of optical detectors and solar cells.
A new estimate on the indirect Coulomb energy
Authors: Benguria Rafael D. , Bley Gonzalo A. , Loss Michael 
Published: July 2011

AbstractHere we prove a new lower bound on the indirect Coulomb energy in quantum mechanics, in terms of the single particle density of the system. The new universal lower bound is an alternative to the classical Lieb–Oxford bound (with a smaller constant, C = 1.45 < CLO = 1.68) but involving an additive kinetic energy term of the single particle density as well. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Off‐center shallow donors in a spherical Si quantum dot with dielectric border
Authors: Cristea M. , Niculescu E. C. 
Published: July 2011

AbstractWithin the effective mass approximation and using a finite element method, the ground state energy and electron cloud localization of the shallow donors in a Si quantum dot (QD) with dielectric border are calculated. Simultaneous effects of dielectric mismatch (DM) at the core–shell interface, the impurity radial position, and the external electric field on the electronic properties are investigated. We found that (i) for a freestanding QD, the binding energy is strongly enhanced due to the additional interactions of the electron with the polarization charges; (ii) the electron cloud distribution can be easily modulated by varying the impurity position; (iii) the electric field‐induced shift in energy levels increases with the DM. Therefore, the electronic energy levels of the nanocrystal could be tuned by properly tailoring the heterostructure parameters (DM with the surrounding matrix, impurity location) as well as by varying the electric field strength. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012