bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research priorities for wind energy and migratory wildlife
Authors: Piorkowski Martin D. , Farnsworth Andrew J. , Fry Michael , Rohrbaugh Ronald W. , Fitzpatrick John W. , Rosenberg Kenneth V. 
Published: December 2011

AbstractWith upcoming global wind‐energy build‐out estimated in millions of units, cumulative environmental impacts must be considered and understood to promote responsible expansion of this renewable energy source. In June 2009, 30 wildlife scientists convened in Racine, Wisconsin, USA to identify key research priorities concerning wind energy's potential impacts on migratory wildlife (birds and bats). This working group suggested 4 areas where improved science is most needed to evaluate the impacts of wind‐energy development on migrating animals more accurately than can be accomplished today: 1) standardized protocols and definitions; 2) new methods and models for assessing and forecasting risk; 3) documenting lethal and sub‐lethal effects at existing wind facilities; and 4) improved facility‐site access, data access, and data management for researchers. Focused research based on these priorities will both quantify potential risks associated with wind‐energy development and help derive science‐based, peer‐reviewed, best‐management practices for existing and future wind projects. © 2011 The Wildlife Society.
Social composition of destination territories and matrix habitat affect red‐cockaded woodpecker dispersal
Authors: Kesler Dylan C. , Walters Jeffrey R. 
Published: December 2011

AbstractWe studied the influence of matrix habitats and destination territory social composition on dispersal choices made by red‐cockaded woodpeckers (Picoides borealis). We compared matrix habitats and social conditions for 165 dispersals documented between 1995 and 2005 with similarly distanced destinations that went unselected. We modeled data with discrete choice analysis methods, and ranked models using a model selection approach. Model‐averaged parameters indicated that juvenile female, and juvenile and helper male red‐cockaded woodpeckers dispersed across matrix forests with characteristics similar to those used for breeding. Models differed for sex and social classes, but results generally indicated that birds chose not to transit forests with greater densities of hardwood trees and young pines, and that dispersal was more likely to occur across forests with more large diameter pine trees. Dispersers of both sexes also chose destinations without non‐breeding helpers that might present aggressive social challenges to dispersers, particularly males. Juvenile females and helper males also preferred to disperse to territories that were currently occupied by breeding woodpeckers. Previous studies documented the influence on dispersal of travel distance, natal area social interactions and resources, and resources at dispersal destinations. Our results extend factors that affect dispersal movement to include matrix habitats traversed by dispersers and the social composition of destination territories. As such, results have key implications for promoting population connectivity and conservation management of endangered red‐cockaded woodpeckers, as well as other resident territorial birds. © 2011 The Wildlife Society.
Arginine methylation of RNA‐binding proteins regulates cell function and differentiation
Authors: Blackwell Ernest , Ceman Stephanie 
Published: December 2011

AbstractArginine methylation is a post‐translational modification that regulates protein function. RNA‐binding proteins are an important class of cell‐function mediators, some of which are methylated on arginine. Early studies of RNA‐binding proteins and arginine methylation are briefly introduced, and the enzymes that mediate this post‐translational modification are described. We review the most common RNA‐binding domains and briefly discuss how they associate with RNAs. We address the following groups of RNA‐binding proteins: hnRNP, Sm, Piwi, Vasa, FMRP, and HuD. hnRNPs were the first RNA‐binding proteins found to be methylated on arginine. The Sm proteins function in RNA processing and germ cell specification. The Piwi proteins are largely germ cell specific and are also required for germ cell production, as is Vasa. FMRP participates in germ cell formation in Drosophila, but is more widely known for its neuronal function. Similarly, HuD plays a role in nervous system development and function. We review the effects of arginine methylation on the function of each protein, then conclude by addressing remaining questions and future directions of arginine methylation as an important and emerging area of regulation. Mol. Reprod. Dev. 79: 163–175, 2012. © 2011 Wiley Periodicals, Inc.
A comparison of in vivo 13C MR brain glycogen quantification at 9.4 and 14.1 T
Authors: van Heeswijk Ruud B. , Pilloud Yves , Morgenthaler Florence D. , Gruetter Rolf 
Published: December 2011

AbstractThe high molecular weight and low concentration of brain glycogen render its noninvasive quantification challenging. Therefore, the precision increase of the quantification by localized 13C MR at 9.4 to 14.1 T was investigated. Signal‐to‐noise ratio increased by 66%, slightly offset by a T1 increase of 332 ± 15 to 521 ± 34 ms. Isotopic enrichment after long‐term 13C administration was comparable (∼40%) as was the nominal linewidth of glycogen C1 (∼50 Hz). Among the factors that contributed to the 66% observed increase in signal‐to‐noise ratio, the T1 relaxation time impacted the effective signal‐to‐noise ratio by only 10% at a repetition time = 1 s. The signal‐to‐noise ratio increase together with the larger spectral dispersion at 14.1 T resulted in a better defined baseline, which allowed for more accurate fitting. Quantified glycogen concentrations were 5.8 ± 0.9 mM at 9.4 T and 6.0 ± 0.4 mM at 14.1 T; the decreased standard deviation demonstrates the compounded effect of increased magnetization and improved baseline on the precision of glycogen quantification. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Investigation of unsaturated polyester composites reinforced by aspen high‐yield pulp fibers
Authors: Du Yicheng , Yan Ning , Kortschot Mark T. 
Published: December 2011

AbstractAspen chemithermomechanical pulp fiber‐reinforced unsaturated polyester (UPE) composites were fabricated using premade paper handsheets. The effects of handsheet wet‐pressing pressure, grammage, and subsequent fabrication methods on the composite properties were evaluated. The composites obtained using the optimum process parameters had tensile moduli and tensile strengths comparable with those of traditional glass fiber‐reinforced UPE composites. The pressed composites had very consistent tensile moduli that were well fitted by the Halpin–Tsai and Tsai–Pagano models. The classical Kelly‐Tyson and Bowyer‐Bader models significantly underestimated the composite tensile strengths and the potential reasons for this discrepancy are discussed. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers
Effect of dynamical converging channels on fiber organization and damage during vane extrusion of sisal fiber‐reinforced polypropylene composites
Authors: Jin‐Ping Qu , Li‐Ming Liu , Bin Tan , Shu‐Rong Liu , Hua‐Xin Chen , Yan‐Hong Feng 
Published: December 2011

AbstractIt is well known that converging channel can generate elongational deformation field. In this study, novel dynamical converging channels were successfully incorporated into plant fiber‐reinforced thermoplastics composites processing. A dynamical elongational deformation field (DEDF) generated by these channels was studied. The fiber organization and damage in the DEDF has been investigated in terms of its relationship to changes in rotating speed of the channels. A vane extruder based on these channels was used to prepare sisal fiber‐reinforced polypropylene composites. By investigating rapidly cooled samples in the vane extruder, sisal fiber in the center part of these channels has an orientation with an angle to the discharging direction. Rotating speed increases from 30 to 90 r/min result in 30.99–42.7% decreases in average fiber length. The issues of fiber distribution and voids formation have been related to the mechanical properties of the composites, particularly tensile strength and modulus. Increased rotating speeds from 30 to 90 r/min results in tensile strength and modulus increases of about 21.3% and 11.6%, respectively. The majority of this change is caused by decreased voids formation with the increases of speed, which is in agreement with scanning electron microscopy of the composites. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers
Effect of nanoclay on the thermal, mechanical, and crystallization behavior of nanofiber webs of nylon‐6
Authors: Saeed Khalid , Park Soo Young 
Published: December 2011

AbstractNylon‐6 and nanoclay/nylon‐6 composite nanofibers were prepared by electrospinning technique, in which formic acid was used as a solvent for good solubility of nylon‐6. The diameter of nylon‐6 and nanoclay/nylon‐6 nanofibers was below 350 nm and had smooth surfaces. The DSC heating curves of nylon‐6 and composites nanofibers show two endotherm behaviors, Tm1 (about 214°C) and Tm2 (about 220°C), corresponding to the melting events of γ‐form and α‐form crystals, respectively. The WAXs study showed that the γ‐crystalline phase predominantly present in both nylon‐6 and nanoclay/nylon‐6 nanofibers. The mechanical properties of the nanoclay/nylon‐6 composite nanofibers were higher than neat nylon‐6 electrospun nanofibers, which was decreased as the quantity of the clay increased. It might be due to the aggregation of nanoclay at high concentration. The thermal properties of the composite nanofibers were higher than neat nylon‐6 nanofibers. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers
Effects of Rubber Addition to an Epoxy Resin and Its Fiber Glass‐Reinforced Composite
Authors: Sobrinho L.L. , Calado V.M.A. , Bastian F.L. 
Published: December 2011

AbstractEpoxy resins are considered as one of the most important class of thermosetting polymers and find extensive use in various fields. However, these materials are characterized by a relatively low toughness. In this respect, many efforts have been made to improve the toughness of cured epoxy resins. In this work, samples of epoxy resin diglycidyl ether of bisphenol‐A and fiber glass‐reinforced composite of this polymer with and without liquid carboxyl‐terminated butadiene acrylonitrile (CTBN) copolymer were prepared to assess the effect of CTBN rubber on the properties of polymeric and composite laminate specimens. The addition of CTBN into the polymeric specimens led to a decrease in the glass transition temperature, fracture stress (from 70.39 to 56.34 MPa), and tensile elasticity modulus (from about 3.51 to 2.65 GPa), accompanied by an increase in elongation (from 2.47 to 5.64%). However, the degradation temperature of the polymeric system was not modified. Infrared analysis evidenced the occurrence of chemical reaction between the two components, and scanning electron microscopy results suggested rubber particles deformation as the prevailing toughening mechanism. The rubber addition in the composite specimens, promoted an increase simultaneous in fracture stress and in elongation at fracture. The elasticity tensile modulus has not changed. This probably results from the increased deformation capacity of the matrix, which prevents its premature cracking, and better adhesion between fibers and matrix observed in the CTBN‐modified composite laminates. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers
Synthesize procedures, mechanical and electrical properties of poly(vinylidene fluoride) nanocomposite thin films containing multiwalled carbon nanotubes
Authors: Zhang Qin , Adebisi Rasheed , Gladden Joseph 
Published: December 2011

AbstractA procedure is proposed to prepare poly(vinylidene fluoride) (PVDF) multiwalled carbon nanotubes (MWCNTs) nanocomposite thin films with improved mechanical and dielectric properties compared to the pure PVDF films. The PVDF/MWCNT mixture with a composition range from 0.0 to 5.0% MWCNTs by weight was formed using solution blending and the ultrasonic dispersion method and then spin coated on a rotating glass substrate to produce films nearly 20 μ thick. Results indicate that the appropriate addition of MWCNTs (up to 3.0 wt%) to PVDF can significantly increase its elastic modulus while decrease its fracture toughness. The elastic modulus shows softening at a 5.0 wt% MWCNT loading. The DC and AC conductivity of the composite films were also examined with various MWCNTs concentrations. The dielectric constants were found more than doubled for 0.5 wt% MWCNTs composite compared to the values for the pure PVDF. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers
Control of the interfacial properties of ultrahigh‐molecular‐weight polyethylene/magnesium hybrid composites through use of atmospheric plasma treatment
Authors: Vargas‐Gonzalez Lionel R. , Walsh Shawn M. , Pappas Daphne D. 
Published: December 2011

AbstractThis work aims to explore the use of lightweight magnesium alloys as an advanced composite material in conjunction with lightweight thermoplastic materials, such as ultrahigh‐molecular‐weight polyethylene (UHMWPE). High throughput, environmentally friendly, atmospheric plasma treatment methods were used to control the interfacial properties and improve the adhesion behavior of metallic/UHMWPE composites. Helium‐oxygen dielectric barrier discharges were used, and the plasma‐activated UHMWPE surfaces were characterized through analytical and mechanical characterization methods. Oxygen content on the treated polymer surfaces increased 18.1–36.0%. A reduction in silicon content combined with characterization through microscopy reveal a preference for the attack of the matrix over the polyethylene fibers. Wetting angles for the treated samples decreased as much as 53.7%. Treated UHMWPE/Mg hybrid samples exhibited lap shear strengths up to 113.7% greater than the control. Both the plasma‐induced surface functionalization with oxygen‐containing polar groups (carboxyl, carbonyl, and hydroxyl groups) and the preferential mild etching of the polymer matrix over the fibers lead to the improvement in adhesion. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers
The influence of nanosilica on styrene free radical polymerization kinetics
Authors: Bera Oskar , Pavličević Jelena , Jovičić Mirjana , Stoiljković Dragoslav , Pilić Branka , Radičević Radmila 
Published: December 2011

AbstractA series of nanocomposites were prepared by in situ polymerization of styrene with different silica content (1, 3, and 5 wt%) with an average particle size of 7 nm. The influence of nanosilica content on the kinetics of styrene free radical bulk polymerization was studied by isothermal differential scanning calorimetry (DSC) at different temperatures (70, 80, and 90°C). Using appropriate kinetic model, describing two reactions observed during styrene polymerization (the first‐order reaction and autoacceleration), it was found that silica presence does not affect the apparent activation energies of both processes. The adsorption of styrene on the silica surface caused the formation of interfacial layer in the structure of hybrid materials. Using suggested equation, the thickness of the interfacial layer was determined to investigate its influence on the glass transition temperature of polystyrene (Tg), which was found not to be affected by silica addition. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers
Nanohybrids based on polymeric ionic liquid prepared from functionalized MWCNTs by modification of anionically synthesized poly(4‐vinylpyridine)
Authors: Katsigiannopoulos Dimitrios , Grana Eftychia , Avgeropoulos Apostolos , Carrasco Pedro M. , Garcia Ignacio , Odriozola Ibon , Diamanti Evmorfia , Gournis Dimitrios 
Published: December 2011

AbstractWe report the synthesis of a composite material comprised of poly(4‐vinylpyridine) (P4VP) grafted on multiwall carbon nanotubes (MWCNTs) and the preparation of a nanohybrid via quaternization of the nitrogen atom per monomeric unit of the polymer chains. 4‐Vinylpyridine was polymerized anionically using high vacuum techniques and was reacted with MWCNTs under vacuum to be grafted on the polymer segments. The composite material was soluble in common solvents and the dispersion of the carbon nanotubes was improved after quaternization due to the formation of polymeric ionic liquid (PIL) of the MWCNTs‐g‐[P4VP‐r‐poly(4ViEtPy+Br‐)] type. The successful synthesis was confirmed with Fourier‐transform infrared and Raman spectroscopies, whereas differential scanning calorimetry was adopted to verify the stability of the polymer's glass transition temperature before and after grafting on the MWCNTs. Moreover, thermogravimetric analysis was used for examining the thermal stability and the PIL formation of the composite. Energy dispersive spectroscopy measurements confirm the precipitation of silver bromide when the MWCNTs‐g‐[P4VP‐r‐poly(4ViEtPy+Br‐)] is reacted with silver nitrite indicating the successful quaternization and formation of the appropriate PIL. High temperature size exclusion chromatography was used for the determination of the molecular characteristics (average molecular weight by number
$\overline M _n$, polydispersity I) of the homopolymer obtained from the filtration of the composite material. Finally, field‐emission scanning electron microscopy was used to verify the successful grafting of the polymer to the MWCNTs. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Amphiphilic gradient copolymers of 2‐methyl‐ and 2‐phenyl‐2‐oxazoline: self‐organization in aqueous media and drug encapsulation
Authors: Milonaki Yanna , Kaditi Eleni , Pispas Stergios , Demetzos Costas 
Published: December 2011

AbstractGradient (or pseudo‐diblock) copolymers were synthesized from 2‐methyl‐2‐oxazoline and 2‐phenyl‐2‐oxazoline monomer mixtures via cationic polymerization. The self‐assembling properties of these biocompatible gradient copolymers in aqueous solutions were investigated, in an effort to use the produced nanostructures as nanocarriers for hydrophobic pharmaceutical molecules. Dynamic and static light scattering as well as AFM measurements showed that the copolymers assemble in different supramolecular nanostructures (spherical micelles, vesicles and aggregates) depending on copolymer composition. Fluorescence spectroscopy studies revealed a microenvironment of unusually high polarity inside the nanostructures. This observation is related partly to the gradient structure of the copolymers. The polymeric nanostructures were stable with time. Their structural properties in different aqueous media—PBS buffer, RPMI solution—simulating conditions used in pharmacological/medicinal studies, have been also investigated and a composition dependent behavior was observed. Finally, the hydrophobic drug indomethacin was successfully encapsulated within the gradient copolymer nanostructures and the properties of the mixed aggregates were studied in respect to the initial copolymer assemblies. The produced aggregates encapsulating indomethacin showed a significant increase of their mass and size compared to original purely polymeric ones. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Acid‐promoted double ring‐opening reaction of bicyclobis (γ‐butyrolactone) with alcohol and its application to polyester synthesis
Authors: Ohsawa Sousuke , Barkakaty Balaka , Sudo Atsushi , Endo Takeshi 
Published: December 2011

AbstractBicyclobis(γ‐butyrolactone) (BBL) bearing methyl group 1a reacted with benzyl alcohol (BnOH) in the presence of p‐toluenesulfonic acid (p‐TsOH) through the double ring‐opening of the bislactone structure to afford the corresponding adduct 2a bearing carboxyl group. The resulting carboxyl group underwent condensation with BnOH to afford the corresponding diester 3a. The second step was quite slow at ambient temperature; however, it was efficiently accelerated by elevating temperature to 120 °C or performing under reduced pressure at 80 °C to afford 3a in an excellent yield. Based on these results, the reaction of 1a with xylene‐α,α‐diol (XyD) was carried out in chlorobenzene at 120 °C to obtain the corresponding polyester bearing ketone group in the side chain. The condensation reaction in the second step was effectively promoted by simultaneous removal of water under reduced pressure. BBLs 1b and 1c bearing reactive groups, isopropenyl and chloromethyl, respectively, were also employed as monomers efficiently. Their reactions with XyD gave the corresponding reactive polyesters bearing methacryloyl and chloroacetyl moieties, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Aqueous cationic olefin polymerization using tris(pentafluorophenyl)gallium and aluminum
Authors: Mathers Robert T. , Lewis Stewart P. 
Published: December 2011

AbstractTris(pentafluorophenyl)gallium (3) and aluminum (7) are active coinitiators for the production of medium‐high molecular weight (MW) polymers of styrene and isobutene (IB) under aqueous reaction conditions. Strong Brønsted acids formed in
situ by reaction of these coinitiators with background moisture present in the monomer droplet (5 and 8, respectively) are believed to be responsible for inducing cationic polymerization of these monomers. Of the two, 7 is the most active for IB polymerization in both aqueous media and anhydrous aliphatic solvents. These results are in contradistinction to tris(pentafluorophenyl)boron (2), which is incapable of polymerizing IB in aqueous or aliphatic media. The MWs of the polyisobutenes (PIBs) produced under aqueous conditions by either coinitiator greatly exceed those formed under similar reaction conditions by the strongly acidic chelating diborane (1,2‐C6F4[B(C6F5)2]2, 1) or diborole (1,2‐C6F4[9‐BC12F8]2, 6). Both 3 and 7 are readily synthesized from the corresponding Group 13 halide compounds in conjunction with bis(pentafluorophenyl)zinc (4). Aqueous polymerization of IB dissolved in aliphatic solvents with 3 or 7 can yield PIBs with relatively narrow polydispersities. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Functionalized block copolymers for preparation of reactive self‐assembled surface patterns
Authors: Stadermann Jan , Riedel Maria , Komber Hartmut , Simon Frank , Voit Brigitte 
Published: December 2011

AbstractTwo phase separating block copolymers equipped with functional groups (acid and alkyne) were synthesized via reversible addition‐fragmentation chain transfer (RAFT) polymerization. Thin films of these materials were prepared and examined with regard to surface morphology, surface composition, and film stability. Self‐assembled structures with domain sizes of about 40 nm were detected through atomik force microscopy (AFM) analysis while X‐ray photoelectron spectroscopy measurements revealed a balanced surface exposure of the two segregated phases. Thus, reactive groups being present in both phases are specifically provided within nanoscopic surface areas. The films showed good stability on exposure to various solvents but the self‐organized surface patterns were only resistant toward ethanol. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011