bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dominance relationships among one‐male units in a provisioned free‐ranging band of the Sichuan snub‐nosed monkeys (Rhinopithecus roxellana) in the Qinling Mountains, China
Authors: Zhang Peng , Watanabe Kunio , Li Baoguo , Qi Xiaoguang 
Published: March 2008

AbstractWe studied the dominance relationships among one‐male units (OMUs) in a provisioned free‐ranging band of the Sichuan snub‐nosed monkeys (Rhinopithecus roxellana) in the Qinling Mountains of central China from 2001 to 2005. The band was composed of 6–8 OMUs that stayed in the band for several years. Linear dominance orders could be detected using displacement interactions with directional asymmetry among OMUs in 82.3±5% of interactions, and ambiguous and reversed interactions in 17.7±5%. The dominance rank of OMUs was positively related with the duration of their stay in the band, and this may be attributed to the association of the resident male with adult females, rather than the fighting ability of resident males, as males do not fight seriously with each other. Subordinate units were observed to merge with dominant units resulting in an elevation of their rank order. The linear dominance relationship among OMUs in the Sichuan snub‐nosed monkeys may have evolved as a result of competition for preferred food trees. Am. J. Primatol. 70:634–641, 2008. © 2008 Wiley‐Liss, Inc.
Chitosan conjugated with deoxycholic acid and gallic acid: A novel biopolymer‐based additive antioxidant for polyethylene
Authors: Pasanphan Wanvimol , Buettner Garry R. , Chirachanchai Suwabun 
Published: March 2008

AbstractChitosan, as a novel bioadditive antioxidant for commodity polymer, is proposed. Chitosan is successfully conjugated with deoxycholic acid and gallic acid (chitosan‐DC‐GA) via a simple reaction using the 1‐ethyl‐3‐(3′‐dimethylaminopropyl) carbodiimide/N‐hydroxysuccinimide conjugating agent at room temperature in a heterogeneous system. Chitosan‐DC‐GA shows a deoxycholic acid (DC) and gallic acid (GA) content of about 40% each. Chitosan‐DC‐GA exhibits DPPH radical scavenging ability with EC50 1 mg mL−1 based on the EPR technique evaluation. A model case study of chitosan‐DC‐GA with low‐density polyethylene (LDPE) confirms improvement in compatibility, as seen from the sheet clarity, as well as the good dispersion of chitosan‐DC‐GA in LDPE matrices, as observed by scanning electron microscope. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and properties of starch‐graft‐acrylic acid/Na‐montmorillonite superabsorbent nanocomposite hydrogels
Authors: Al Ebru , Güçlü Gamze , İyim Tülin Banu , Emik Serkan , Özgümüş Saadet 
Published: March 2008

AbstractThe graft copolymerization of acrylic acid (AA) onto starch was carried out with monomer/starch weight ratio = 1.5. Cerium ammonium nitrate (CAN) and N,N′‐methylenebis acrylamide (NMBA) were used as initiator and crosslink agent, respectively. Na‐montmorillonite was used as nanoparticles. Starch‐graft‐acrylic acid/Na‐MMT (S‐g‐AA/MMT) nanocomposite hydrogels were characterized by X‐ray diffraction (XRD) and FTIR analysis. The effect of Na‐MMT content in nanocomposite hydrogels on the swelling behavior was investigated. Increasing the Na‐MMT/monomers ratio up to 1% causes an increment in water absorbency, which indicates that Na‐MMT can improve the ability of water absorbency but further increase of Na‐MMT causes a decrease in water absorbency. In addition, we describe the removal of safranine T from aqueous solutions using S‐g‐AA/MMT nanocomposite hydrogels. Effects of various parameters such as treatment time, initial dye concentration, and amount of the Na‐MMT were investigated. The Freundlich equations were used to fit the equilibrium isotherms. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of high temperature alkali cooking on the constituents, structure and thermal degradation of hemp fiber
Authors: Feng Xin‐xing , Chen Jian‐yong , Zhang Hua‐peng 
Published: March 2008

AbstractDegumming of hemp fiber by high temperature alkali cooking was investigated, and the effect of temperature and dosage of alkali on the constituents, structure, and thermal degradation of hemp fiber was also discussed in this work. The morphology, structure, and thermal degradation of hemp fiber after high temperature cooking were investigated through SEM, FTIR, WAXD, and TG analysis. The results indicated that the high temperature cooking process was effective for removing hemicelluloses and lignin and could also improve the thermal stability of cellulose. Crystallinity index of the treated hemp fiber was increased, which was related to the cooking temperature and NaOH dosage. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermal and physicomechanical properties of ethylene‐vinyl acetate copolymer and layered double hydroxide composites
Authors: Ramaraj B. , Yoon Kuk Ro 
Published: March 2008

AbstractA series of ethylene‐vinyl acetate (EVA) copolymer films have been prepared with different compositions viz. 2, 4, 6, and 8 wt % layered double hydroxide (LDH) nanoparticles by solution intercalation method. These solution‐casted EVA/LDH nanocomposite films were dried and characterized by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. EVA/LDH films were further tested for tensile strength, density, moisture content, solubility resistance, flammability, and electrical properties. The DSC and FTIR analysis indicate strong interactions between the LDH layers and vinyl acetate groups in EVA. Further, EVA nanocomposite films show enhanced tensile strength, limiting oxygen index (LOI), and flammability rating for the addition of LDH without sacrificing the electrical properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Thermophysical and thermomechanical properties of Norland Optical Adhesives and liquid crystal composites
Authors: Benmouna Réda , Benyoucef Boumediène 
Published: March 2008

AbstractThermophysical and thermomechanical properties of UV‐cured Norland Optical Adhesives (NOA65) and low molecular weight Liquid Crystal E7 systems were investigated. Thin films of Polymer Dispersed Liquid Crystal were prepared by Polymerization Induced Phase Separation and UV‐curing. Phase diagrams were established using Polarized Optical Microscopy and DSC to determine the lines of nematic to isotropic phase transition as well as the glass transition temperature changes with the system composition. Mechanical measurements were performed in the static and dynamic modes to determine the moduli in terms of the curing time, the temperature and the amount of low molecular weight liquid crystal molecules. Thermomechanical measurements were found to overestimate the glass transition temperature as compared to calorimetric data. Variations of the Young's modulus and the molecular weight defining the mesh size of the network were analyzed in terms of the curing time and liquid crystal concentration. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Properties of styrene‐methyl methacrylate grafted DPNR latex at different monomer concentrations
Authors: Man Siti Hajjar Che , Hashim Azanam S. , Akil Hazizan Md. 
Published: March 2008

AbstractThe graft copolymerization of styrene and methyl methacrylate (MMA) on to deproteinized natural rubber (DPNR) latex was carried out. The effect of monomer concentrations on grafting efficiency, thermal and mechanical properties was studied. The synthesized graft copolymers were characterized by proton nuclear magnetic resonance (1H NMR) and the highest grafting efficiency was found at 20 wt % monomer concentration. At low monomer concentration (10 wt %) the grafting was not significant and at 30 wt %, the grafting efficiency was slightly decreased. The thermal properties of graft copolymers were analyzed using differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). The degradation temperature (Tdeg) of the graft copolymer was increased with the increase in monomer concentration which indicates the improvement in thermal stability. The DSC result showed improvement in miscibility between the components as the monomer concentration increased. The mechanical properties of gum and filled modified NR were also investigated in terms of tensile strength, tensile modulus and elongation at break. The tensile strength and elongation at break decreased with an increase in monomer concentration while tensile modulus increased as the monomer concentration increased. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Dynamic properties of rubber vibration isolators and antivibration performance of ethylene–propylene–diene monomer/nylon 6 blend systems
Authors: Wu Jyh‐Horng , Li Chia‐Hao , Chiu Hsien‐Tang , Shong Zhi‐Jian 
Published: March 2008

AbstractThis article examines thermoplastic elastomers (TPEs) and thermoplastic vulcanizates (TPVs) as two types of elastomers from melt‐blended and dynamically vulcanized ethylene–propylene–diene monomer (EPDM) rubber materials and nylon 6 plastic materials. A series of investigations were conducted on the mechanical properties, morphology, dynamic mechanical properties, hysteresis behavior, and dynamic antivibration properties with different nylon 6 contents. The experimental results showed that the incompatibility between EPDM and nylon 6 led to the easy destruction of the TPV materials in two interfacial polymers upon the application of an external force. Thus, after a dynamic vulcanization process, the mechanical properties of the EPDM/nylon 6 blends were not as good as those of the TPE materials. In terms of morphology, nylon 6 plastics were uniformly distributed in the EPDM/nylon 6 blends during the EPDM rubber phase before vulcanization was performed. After the dynamic vulcanization, phase inversion was produced in which rubber microparticles were formed and dispersed in the nylon 6 plastic phase. The results of dynamic mechanical analysis, compression vibration hysteresis behavior, and dynamic property antivibration experiments showed that the blends provided better vibration isolation and antivibration performance after the amount of nylon 6 was increased and EPDM and nylon 6 were blended through dynamic vulcanization. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Proteome‐based identification of fusion partner for high‐level extracellular production of recombinant proteins in Escherichia coli
Authors: Qian Zhi‐Gang , Xia Xiao‐Xia , Choi Jong Hyun , Lee Sang Yup 
Published: March 2008

AbstractExtracellular production of recombinant proteins in Escherichia coli has several advantages over cytoplasmic or periplasmic production. However, nonpathogenic laboratory strains of E. coli generally excrete only trace amounts of proteins into the culture medium under normal growth conditions. Here we report a systematic proteome‐based approach for developing a system for high‐level extracellular production of recombinant proteins in E. coli. First, we analyzed the extracellular proteome of an E. coli B strain, BL21(DE3), to identify naturally excreted proteins, assuming that these proteins may serve as potential fusion partners for the production of recombinant proteins in the medium. Next, overexpression and excretion studies were performed for the 20 selected fusion partners with molecular weights below 40 kDa. Twelve of them were found to allow fused proteins to excrete into the medium at considerable levels. The most efficient excreting fusion partner, OsmY, was used as a carrier protein to excrete heterologous proteins into the medium. E. coli alkaline phosphatase, Bacillus subtilis α‐amylase, and human leptin used as model proteins could all be excreted into the medium at concentrations ranging from 5 to 64 mg/L during the flask cultivation. When only the signal peptide or the mature part of OsmY was used as a fusion partner, no such excretion was observed; this confirmed that these proteins were truly excreted rather than released by outer membrane leakage. The recombinant protein of interest could be recovered by cleaving off the fusion partner by enterokinase as demonstrated for alkaline phosphatase as an example. High cell density cultivation allowed production of these proteins to the levels of 250–700 mg/L in the culture medium, suggesting the good potential of this approach for the excretory production of recombinant proteins. Biotechnol. Bioeng. 2008;101: 587–601. © 2008 Wiley Periodicals, Inc.
Effect of surface roughness of Ti, Zr, and TiZr on apatite precipitation from simulated body fluid
Authors: Chen Xiaobo , Nouri Alireza , Li Yuncang , Lin Jianguo , Hodgson Peter D. , Wen Cui'e 
Published: March 2008

AbstractSome of the critical properties for a successful orthopedic or dental implant material are its biocompatibility and bioactivity. Pure titanium (Ti) and zirconium (Zr) are widely accepted as biocompatible metals, due to their non‐toxicity. While the bioactivity of Ti and some Ti alloys has been extensively investigated, there is still insufficient data for Zr and titanium–zirconium (TiZr) alloys. In the present study, the bioactivity, that is, the apatite forming ability on the alkali and heat treated surfaces of Ti, Zr, and TiZr alloy in simulated body fluid (SBF), was studied. In particular, the effect of the surface roughness characteristics on the bioactivity was evaluated for the first time. The results indicate that the pretreated Ti, Zr and TiZr alloy could form apatite coating on their surfaces. It should be noted that the surface roughness also critically affected the bioactivity of these pretreated metallic samples. A surface morphology with an average roughness of approximately 0.6 µm led to the fastest apatite formation on the metal surfaces. This apatite layer on the metal surface is expected to bond to the surrounding bones directly after implantation. Biotechnol. Bioeng. 2008;101: 378–387. © 2008 Wiley Periodicals, Inc.
Directed evolution of LuxI for enhanced OHHL production
Authors: Kambam Pavan Kumar Reddy , Sayut Daniel J. , Niu Yan , Eriksen Dawn T. , Sun Lianhong 
Published: March 2008

AbstractQuorum sensing is a common mechanism used by bacteria to coordinate population behavior, and is involved in a variety of biological processes, such as bioluminescence, virulence factor synthesis, antibiotic production, and biofilm formation. To engineer the LuxI enzyme of the LuxI–LuxR quorum‐sensing system, we developed a high throughput genetic selection to identify LuxI mutants with improved OHHL (3‐oxo‐hexanoyl homoserine lactone) synthesis in E. coli. Using this genetic selection, we created LuxI mutants with improved OHHL synthesis rates and yields through directed evolution, identifying three LuxI mutants after two generations. An in vivo semi‐quantitative method allowed for verification of the genetic screen and OHHL yields were quantified using HPLC–MS/MS, revealing an 80‐fold increase in a mutant culture compared to the wildtype culture. In addition to OHHL, the yields of C6HSL (hexanoyl homoserine lactone) and C8HSL (octanoyl homoserine lactone) were also improved, and a slight change in substrate specificity towards C6HSL production was observed. Based on alignment with the crystal structure of EsaI, a homolog of LuxI, two mutations are most likely involved in enhancing the interactions between the enzyme and the substrates. The high throughput genetic selection and the semi‐quantitative method can be conveniently modified for the directed evolution of LuxI homologs. The identification of these LuxI mutants has implications in synthetic biology, where they can be used for the construction of artificial genetic circuits. In addition, development of drugs that specifically target quorum sensing to attenuate the pathogenesis of gram‐negative infectious bacteria might also benefit from the insights into the molecular mechanism of quorum sensing revealed by the amino acid substitutions. Biotechnol. Bioeng. 2008;101: 263–272. © 2008 Wiley Periodicals, Inc.
Single‐layer perceptron and dynamic neuron implementing linearly non‐separable Boolean functions
Authors: Chen Fangyue , Tang Wenhui , Chen Guanrong 
Published: March 2008

AbstractThis paper presents a single‐layer perceptron (SLP) scheme with an impulse activation function (IAF) and a dynamic neuron (DN) with a trapezoidal activation function (TAF). Combining with some interesting properties of the offset levels, it is shown that many linearly non‐separable Boolean functions can be realized by using only one SLPwIAF or one DNwTAF. In the present work, a few appropriate IAF and TAF are adopted, and the inverse offset level method is used for the design of the SLPwIAF synaptic weights and the DNwTAF templates. The XOR and NXOR Boolean operations with two inputs and all 152 non‐separable Boolean functions with three inputs can be easily implemented by one SLPwIAF or one DNwTAF. Finally, the entire set of 152 DNwTAF templates associated with 152 non‐separable Boolean functions of three inputs is completely listed. Copyright © 2008 John Wiley & Sons, Ltd.
A Nearly Planar Stannene with a Reactive Tin–Carbon Double Bond
Authors: Fatah Abdoul , El Ayoubi Rami , Gornitzka Heinz , Ranaivonjatovo Henri , Escudié Jean 
Published: March 2008

AbstractBis(2,4,6‐triisopropylphenyl)‐2,7‐di‐tert‐butylfluorenylidenestannane, Tip2Sn=CR2, an isolable stannene that displays a deep‐purple colour, was synthesized by dehydrofluorination of the corresponding fluorostannane by tert‐butyllithium. It exhibits the shortest Sn=C distance [2.003(5) Å] and the slightest twisting around this unsaturation (10°) among the known stannenes. Its reaction with benzaldehyde according to a [2+2] cycloaddition and that with α‐ethylenic aldehydes and ketones such as crotonaldehyde and methyl vinyl ketone by a [2+4] cycloaddition proceeded in near‐quantitative yield. With acetone, an ene reaction occurred. The four‐membered ring 1,2‐oxastannacyclobutane obtained with benzaldehyde underwent a ring expansion with a second molecule of benzaldehyde to afford the six‐membered ring dioxastannacyclohexane.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Theoretical Study on a Class of Organometallic Complexes Based on All‐Metal Aromatic Ga3– Through Sandwiching Stabilization
Authors: Yang Li‐ming , Li Xiao‐ping , Ding Yi‐hong , Sun Chia‐chung 
Published: March 2008

AbstractWe report the theoretical study on a class of organometallic complexes containing the all‐metal aromatic unit Ga3– on the basis of density functional theory calculations on a series of model sandwich‐like compounds [DM(Ga3)]q– as well as those of the saturated compounds [DMn(Ga3)] [D = Ga3–, Cp–(C5H5–); M = Li, Na, K, Be, Mg, Ca] and extended compounds (Cp–)m(Li+)n(Ga3–)o (m, n, and o are integers). For the six metals, the all‐metal aromatic Ga3– can only be assembled and stabilized in the “heterodecked sandwich” scheme (e.g. [CpM(Ga3)]q–) so as to avoid cluster fusion. Moreover, we designed a novel class of all‐metal aromatic “metalloid” compounds. The ground state heterodecked sandwich species (Cp)–(M)q+(Ga3)– (M = Li, Na, K, q = 1; M = Be, Mg, Ca, q = 2) and the extended sandwich species (Cp–)m(Li+)n(Ga3–)o are mainly ionic bonded, cluster‐assembled “polyatomic molecule”, grown from the combination of Cp–, M atoms, and Ga3–. As a prototype for ionic bonding involving intact Ga3– subunits, [CpM(Ga3)]q– may be a stepping stone toward forming ionic, cluster‐assembled all‐metal aromatic Ga3‐based bulk solids or materials. Additionally, our results for the first time showed that the electronic, structural, and aromatic properties of the all‐metal aromatic Ga3– could be well retained during cluster assembly, which is indicative of “building block” character. Bearing the significant difference in bonding patterns between our designed metalloid compounds and the known metalloid species, synthesis of these novel species might present an attractive challenge to experimental chemists. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A Carbonyl Group Bridging Four Metal Atoms in a Homoleptic Carbonylmetal Cluster: The Remarkable Case of ­Co4(CO)11
Authors: Zhang Xiuhui , Li Qian‐shu , Xie Yaoming , King R. Bruce , Schaefer Henry F. 
Published: March 2008

AbstractThe unsaturated Co4(CO)11 is predicted by density functional theory (B3LYP and BP86 functionals) to have a structure with one μ4‐CO group bridging all four cobalt atoms in a Co4 butterfly, with five Co–Co bonds in the range 2.44–2.56 Å. This μ4‐CO group is predicted to have a relatively long C–O bond of 1.226 Å (BP86) with a correspondingly low ν(CO) frequency of 1636 cm–1. Co4(CO)11 structures of higher energy have Co4 tetrahedra (6 Co–Co bonds) or Co4 butterflies (5 Co–Co bonds) with a collection of terminal, edge‐bridging, and face‐bridging CO groups forming a total of 15 or 16 Co–C bonds. The predicted molecular structures show no signs of cobalt–cobalt multiple bonding. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Reusable Polymer‐Supported Amine‐Copper Catalyst for the Formation of α‐Alkylidene Cyclic Carbonates in Supercritical Carbon Dioxide
Authors: Jiang Huan‐Feng , Wang A‐Zhong , Liu Hai‐Ling , Qi Chao‐Rong 
Published: March 2008

AbstractA green, simple and effective polymer‐supported catalytic system has been developed for the cyclization of propargyl alcohols with carbon dioxide (CO2). α‐Alkylidene cyclic carbonates were obtained in satisfactory isolated yields in most cases. The catalyst could be recovered by simple filtration and reused several times without significant loss of activity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Solvent‐Dependent Regiochemical Cyclotrimerisation of Phenylacetylene with Cobalt Catalysts Containing Disulfide Ligands: A Case Study
Authors: Hilt Gerhard , Hengst Christoph , Hess Wilfried 
Published: March 2008

AbstractThe intermolecular cobalt‐catalysed cyclotrimerisation of phenylacetylene as a benchmark alkyne with [1,2‐bis(4‐methoxyphenylthio)ethane]cobalt dibromide gave the symmetrical 1,3,5‐triphenylbenzene as the major product when dichloromethane was used as the solvent, whereas the unsymmetrical 1,2,4‐trisubstituted product was obtained in acetonitrile in quantitative yield. Optimisation of the aromatic and aliphatic disulfide ligands in different solvents is discussed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Geomorphology of the onset area of a paleo‐ice stream, Marguerite Bay, Antarctic Peninsula
Authors: Anderson John B. , Fretwell Lisa Oakes 
Published: March 2008

AbstractGeomorphic features indicate that both glacial and melt‐water erosion characterize the onset area of the ancestral Marguerite Ice Stream. The large size of these features indicates that they formed over repeated glacial cycles, most recently during the Last Glacial Maximum. Ice drainage within the bay and on the inner continental shelf was strongly influenced by tectonic fabric.Deep, isolated basins surrounded by rugged bedrock bathymetry characterize the innermost part of the bay. Drumlins and other streamlined features occur in the floors of these basins at depths of up to 900 m. The outer bay has three large interconnected basins. Drumlins and megaflutings within these basins indicate ice was grounded at water depths up to 1000 m. The orientations of these features show convergence of drainage from the northeast, east and south into the Marguerite paleo‐ice stream. On the inner continental shelf, the ice converged into a single, wide trough dominated by mega‐scale glacial lineations. This transition in geomorphic features from drumlins and megaflutings to mega‐scale glacial lineations occurs at the location on the continental shelf where sedimentary strata blanket bedrock, and marks a zone of acceleration of the ice stream.The glacially sculptured geomorphic features within Marguerite Bay co‐exist with anastomosing, radial and relatively straight channels, which become increasingly focused in a seaward direction. This implies that a well organized subglacial drainage system existed within the bay at some point in the past. Copyright © 2008 John Wiley & Sons, Ltd.