bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduction of percolation threshold through double percolation in melt‐blended polycarbonate/acrylonitrile butadiene styrene/multiwall carbon nanotubes elastomer nanocomposites
Authors: Maiti Sandip , Shrivastava Nilesh K. , Khatua B.B. 
Published: March 2013

AbstractWe demonstrate a method that involves melt blending of polycarbonate (PC) and melt‐blended acrylonitrile butadiene styrene (ABS) with multiwall carbon nanotubes (MWCNTs) to prepare electrically conducting PC/MWCNT nanocomposites at significantly low MWCNT loading. The partial solubility of ABS in PC led to a selective dispersion of the MWCNTs in the ABS phase after melt‐blending PC and ABS. Thus, a sudden rise in electrical conductivity (∼108 orders of magnitude) of the nanocomposites was found at 0.328 vol% of MWCNT, which was explained in terms of double percolation phenomena. By optimizing the ratio of PC and the ABS–MWCNT mixture, an electrical conductivity of 5.58 × 10−5 and 7.23 × 10−3 S cm−1 was achieved in the nanocomposites with MWCNT loading as low as 0.458 and 1.188 vol%, respectively. Transmission electron microscopy revealed a good dispersion and distribution of the MWCNTs in the ABS phase, leading to the formation of continuous MWCNT network structure throughout the matrix even at very low MWCNT loading. Storage modulus and thermal stability of the PC were also increased by the presence of a small amount of MWCNTs in the nanocomposites.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Natural fiber blend—nylon 6 composites
Authors: Ozen Ertan , Kiziltas Alper , Kiziltas Esra Erbas , Gardner Douglas J. 
Published: March 2013

AbstractIn this study, engineering thermoplastic composites were prepared from natural fiber blend–filled nylon 6. Natural fiber blend from a mixture of kenaf, flax, and hemp fibers were added to nylon 6 using melt mixing to produce compounded pellets. The natural fibers/ nylon6 composites with varying concentrations of natural fibers (from 5 to 20 wt%) were prepared by injection molding. The tensile and flexural properties of the nylon 6 composites were increased significantly with the addition of the natural fiber blend. The maximum strength and modulus of elasticity for the nylon 6 composites were achieved at a natural fiber blend weight fraction of 20%. The Izod impact strength of composites decreased with the incorporation of natural fibers without any surface treatments and coupling agent. The melt flow index (MFI) also decreased with increasing natural fiber blend loading. The results of tensile and flexural modulus of elasticity (FMOE) are in accordance with the rheological data from the MFI measurements. The increase in the tensile and flexural properties indicated that efficient bonding occurred between the natural fibers and nylon 6. No fiber pullout was observed during the scanning electron microscopic analysis of the fracture surfaces. The higher mechanical results with lower density demonstrate that a natural fiber blend can be used as a sufficient reinforcing material for low‐cost, eco‐friendly composites in the automotive industry and in other applications such as the building and construction industries, packaging, consumer products, etc.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Dynamic mechanical analysis of elastic modulus development of dental composites
Authors: Jian Yu , He Yong , Zhao Liyan , Yang Wantai , Nie Jun 
Published: March 2013

AbstractA method based on the compression mode of a dynamic mechanical analysis was first reported to measure the real‐time elastic modulus of dental composites during photopolymerization. By using this novel method, it was easy to investigate the real‐time development of mechanical property of dental materials. Because the modulus development was the consequence of photopolymerization, the modulus development was governed by the double‐bond conversion. High energy dose obtained by using high light intensity or long exposure time increased the “final” modulus because of the increase of conversion, but decreased the contribution of postpolymerization to the “final” modulus because of mobility limitation at high conversion. Moreover, the vitrification effect played the important role for the development of elastic modulus. The modulus significantly increased in the stage of vitrification.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
A glimpse of fear: Fast detection of threatening targets in visual search with brief stimulus durations
Authors: Soares Sandra C. , Esteves Francisco 
Published: March 2013

AbstractReliable detection of a threat based on temporally restricted information allows organisms to activate their defensive mechanisms. In the present study we investigated attentional efficiency for prototypical evolutionarily relevant stimuli, snakes (compared with spiders and mushrooms), during visual search conditions in which displays were presented for brief durations and under conditions of high perceptual load. Participants were exposed to a visual search paradigm in which the duration of the display varied between 150 and 300 ms. Perceptual load was manipulated using small, medium, and larger displays (4, 6, and 8 items, respectively). The results showed that fear stimuli, compared with neutral stimuli, were more accurately and quickly detected under both visually degraded conditions. The results also showed differences between the two categories of fear‐relevant stimuli (snakes and spiders) in their dependency on perceptual load manipulations. Snake targets were overall detected more accurately than spiders, with this snake advantage effect being more clear‐cut with many distracters (high load) than with few (low load). The results were interpreted in light of an evolutionary‐based theory (the snake detection theory), which posits that snakes are the prototypical predators of primates.
Introduction and empirical assessment of executive functioning as a predictor of job performance
Authors: Culbertson Satoris S. , Huffcutt Allen I. , Goebl Allen P. 
Published: March 2013

AbstractThe primary purposes of this study were (a) to introduce the concept of executive functioning (higher‐level cognitive processes which monitor events, actions, and outcomes) to the employee selection literature and (b) to provide an empirical assessment of executive functioning in relation to key selection variables. Two of the three main components of executive functioning (set shifting and inhibition) appear to have considerable potential for selection because of their unique nature (e.g., self‐directed, goal‐oriented) and because they appear to be only modestly associated with general mental ability. While our empirical results were inconsistent, there may be underlying reasons for this, such as the unstable nature of the retail job sector. We believe there is considerable justification for continued exploration of this unique and potentially promising construct, and identify a number of directions for future research.
Electrochemiluminescence biosensor for Ramos cells based on a nanostructured conducting polymer composite material (PICA‐MWNTs)
Authors: Nie Guangming , Bai Zhimin , Yu Wenying , Zhang Lin 
Published: March 2013

ABSTRACTA novel nanostructured conducting polymer (PICA‐MWNTs) is easily prepared by direct electrodeposition of indole‐6‐carboxylic acid (ICA) and carboxylic groups ended multiwalled carbon nanotubes (MWNTs) in acetonitrile in one step. The resulting PICA‐MWNTs composites with larger specific surface area and quite a few functionalized carboxylic acid groups are naturally integrated as a continuous uniform film on the electrode. CdSe quantum dots electrochemiluminescence biosensor with high sensitivity for detection of Ramos cells is fabricated based on PICA‐MWNTs. Coupled with nanoparticle‐amplification technnique, this sensor shows high sensitivity and good selectivity for Ramos cells with a low detection limit of 390 cells mL−1. This result provides an avenue for a simple and sensitive approach for detection of Ramos cells, which may have great potential in clinical applications. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2385–2392
Efficient terpolymerization of ethylene and styrene with α‐olefins by aryloxo‐modified half‐titanocene‐based catalysts and cocatalyst systems
Authors: Apisuk Wannida , Suzuki Naohiro , Kim Hyun Joon , Kim Dong Hyun , Kitiyanan Boonyarach , Nomura Kotohiro 
Published: March 2013

ABSTRACTAryloxo‐modified half‐titanocenes, Cp′TiCl2(O‐2,6‐iPr2C6H3) [Cp′ = Cp* (1), tBuC5H4 (2)], catalyze terpolymerization of ethylene and styrene with α‐olefin (1‐hexene and 1‐decene) efficiently in the presence of cocatalyst, affording high‐molecular‐weight polymers with unimodal distributions (compositions). Efficient comonomer incorporations have been achieved by these catalysts. The content of each comonomer (α‐olefin, styrene, etc.) could be controlled by varying the comonomer concentration charged, and resonances ascribed to styrene and α‐olefin repeated insertion were negligible. The terpolymerization with p‐methylstyrene (p‐MS) in place of styrene also proceeded in the presence of [PhN(H)Me2][B(C6F5)4] and AliBu3 cocatalyst, and p‐MS was incorporated in an efficient matter, affording high‐molecular‐weight polymers with uniform molecular weight distributions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2565–2574
Efficient ethylene/norbornene copolymerization by half‐titanocenes containing imidazolin‐2‐iminato ligands and MAO catalyst systems
Authors: Apisuk Wannida , Trambitas Alexandra G. , Kitiyanan Boonyarach , Tamm Matthias , Nomura Kotohiro 
Published: March 2013

ABSTRACTEthylene copolymerizations with norbornene (NBE) using half‐titanocenes containing imidazolin‐2‐iminato ligands, Cp′TiCl2[1,3‐R2(CHN)2CN] [Cp′ = Cp (1), tBuC5H4 (2); R = tBu (a), 2,6‐iPr2C6H3 (b)], have been explored in the presence of methylaluminoxane (MAO) cocatalyst. Complex 1a exhibited remarkable catalytic activity with better NBE incorporation, affording high‐molecular‐weight copolymers with uniform molecular weight distributions, whereas the tert‐BuC5H4 analog (2a) showed low activity, and the resultant polymer prepared by the Cp‐2,6‐diisopropylphenyl analog (1b) possessed broad molecular weight distribution. The microstructure analysis of the poly(ethylene‐co‐NBE)s prepared by 1a suggests the formation of random copolymers including two and three NBE repeating units. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2575–2580
Synthesis and characterization of tridentate [O−N(H)X] titanium complexes and their applications in olefin polymerization
Authors: Wan Da‐Wei , Chen Zhou , Gao Yan‐Shan , Shen Qi , Sun Xiu‐Li , Tang Yong 
Published: March 2013

ABSTRACTA series of [O−N(H)X]TiCl3 complexes derived from (arylamino)methylene phenol are prepared. The molecular structures of the complexes are characterized by 1H NMR, 13C NMR, and X‐ray analysis. Upon activation with modified methylaluminoxane (MMAO), the titanium complexes display high thermal stability and single‐site like ethylene (co)polymerization behavior at the temperatures of up to 150 °C. 1‐Octene and 1‐octadencene prove suitable to be incorporated into polyethylene backbone at 110 °C and the highest activity of 1.89 × 106 g/mol(Ti)·h·atm can be achieved. The pendant group X has great influence on the catalytic behaviors of the complexes, and PPh2 proves to be the optimal group. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2495–2503
Co‐morbid mental health conditions in cancer patients at working age – prevalence, risk profiles, and care uptake
Authors: Singer S. , Szalai C. , Briest S. , Brown A. , Dietz A. , Einenkel J. , Jonas S. , Konnopka A. , Papsdorf K. , Langanke D. , Löbner M. , Schiefke F. , Stolzenburg J.‐U. , Weimann A. , Wirtz H. , König H. H. , Riedel‐Heller S. 
Published: March 2013

SummaryObjectiveThis study examined the prevalence of mental health conditions in cancer patients, the role of socioeconomic position in relation to that, and the use of professional mental health care.MethodsProspective cohort with measurements at the beginning of inpatient treatment (baseline) and 3, 9, and 15 months after baseline using structured clinical interviews based on DSM‐IV, questionnaires, and medical records.ResultsAt baseline, 149 out of 502 cancer patients (30%) were diagnosed with a mental health condition. Prevalence was associated with unemployment (odds ratio [OR] 2.0), fatigue (OR 1.9), and pain (OR 1.7).Of those with mental health conditions, 9% saw a psychotherapist within 3 months of the diagnosis, 19% after 9 months, and 11% after 15 months. Mental health care use was higher in patients with children ≤18 years (OR 3.3) and somatic co‐morbidity (OR 2.6). There was no evidence for an effect of sex on the use of mental health care.ConclusionFew cancer patients with psychiatric disorders receive professional mental health care early enough. If patients are unemployed or if they suffer from fatigue or pain, special attention should be paid because the risk of having a mental health condition is increased in these patients. Copyright © 2013 John Wiley & Sons, Ltd.
The Mechanism of Plasma Destruction of Enalapril and Related Metabolites in Water
Authors: Magureanu Monica , Dobrin Daniela , Mandache Nicolae Bogdan , Bradu Corina , Medvedovici Andrei , Parvulescu Vasile I. 
Published: March 2013

AbstractA pulsed dielectric barrier discharge was used for the decomposition of enalapril, its metabolite, enalaprilat, its degradation by‐product, diketopiperazine, as well as their combination, in aqueous solution. The discharge was generated at the interface between gas and the solution which flows as a film on the surface of the inner electrode of the plasma reactor. The degradation mechanism of the studied compounds and the temporal evolution of the reaction intermediates were established from LC–MS analysis. A wide variety of degradation by‐products were formed; at least six new derivatives, not mentioned in literature, were observed. However, most of these by‐products were subsequently degraded to small molecules. The mineralization degree, determined from TOC and COD measurements, was approximately 40%. magnified image
CryoGRID 1.0: Permafrost Distribution in Norway estimated by a Spatial Numerical Model
Authors: Gisnås K. , Etzelmüller B. , Farbrot H. , Schuler T. V. , Westermann S. 
Published: March 2013

ABSTRACTCryoGRID 1.0 provides an equilibrium model of permafrost distribution in Norway at a spatial resolution of 1 km2. The approach was forced with gridded data on daily air temperature and snow cover. Ground thermal properties for different bedrock types and sediment covers were derived from surveys and geological maps to yield distributions of thermal conductivity, heat capacity and water content. The distribution of blockfields was derived from satellite images adapting a newly developed classification scheme. The model was evaluated using measured ground surface and ground temperatures, yielding a realistic description of the permafrost distribution in mainland Norway.The model results show that permafrost underlies sites mainly with exposed bedrock or covered by coarse‐grained sediments, such as blockfields and coarse tills. In northern Norway, palsa mires are abundant and organic material and vegetation strongly influence the ground thermal regime. Modelling suggests that permafrost in equilibrium with the 1981–2010 climate presently underlies between 6.1 per cent and 6.4 per cent of the total area of mainland Norway, an area significantly smaller than that modelled for the Little Ice Age climate (14%). CryoGRID 1.0 was subsequently forced using output from a regional climate model for the 2071–2100 period, which suggests that severe permafrost degradation will occur, leaving permafrost beneath an area of just 0.2 per cent of mainland Norway. Copyright © 2013 John Wiley & Sons, Ltd.
Three dimensional structure of the anthrax toxin translocon–lethal factor complex by cryo‐electron microscopy
Authors: Gogol E. P. , Akkaladevi N. , Szerszen L. , Mukherjee S. , Chollet‐Hinton L. , Katayama H. , Pentelute B. L. , Collier R. J. , Fisher M. T. 
Published: March 2013

AbstractWe have visualized by cryo‐electron microscopy (cryo‐EM) the complex of the anthrax protective antigen (PA) translocon and the N‐terminal domain of anthrax lethal factor (LFN) inserted into a nanodisc model lipid bilayer. We have determined the structure of this complex at a nominal resolution of 16 Å by single‐particle analysis and three‐dimensional reconstruction. Consistent with our previous analysis of negatively stained unliganded PA, the translocon comprises a globular structure (cap) separated from the nanodisc bilayer by a narrow stalk that terminates in a transmembrane channel (incompletely distinguished in this reconstruction). The globular cap is larger than the unliganded PA pore, probably due to distortions introduced in the previous negatively stained structures. The cap exhibits larger, more distinct radial protrusions, previously identified with PA domain three, fitted by elements of the NMFF PA prepore crystal structure. The presence of LFN, though not distinguished due to the seven‐fold averaging used in the reconstruction, contributes to the distinct protrusions on the cap rim volume distal to the membrane. Furthermore, the lumen of the cap region is less resolved than the unliganded negatively stained PA, due to the low contrast obtained in our images of this specimen. Presence of the LFN extended helix and N terminal unstructured regions may also contribute to this additional internal density within the interior of the cap. Initial NMFF fitting of the cryoEM‐defined PA pore cap region positions the Phe clamp region of the PA pore translocon directly above an internal vestibule, consistent with its role in toxin translocation.
First‐principles calculations of structural and electronic properties of pure and Tm2+‐doped SrCl2
Authors: Ma C.‐G. , Brik M. G. 
Published: March 2013

AbstractThe structural and electronic properties of pure and Tm2+‐doped SrCl2 have been studied in details using the hybrid density‐functional theory, as implemented in CRYSTAL09 code. The calculated local geometry structures of the doped site, electronic band structures, density of states, and Mulliken populations for the pure and doped crystals are analyzed and compared to reveal the changes induced by the impurity ion. Additionally, based on the optimized local structure, the 4f13 and 4f125d energy levels of Tm2+ ions in SrCl2 are calculated by employing the exchange charge model of the semi‐empirical crystal‐field theory. The simulated 4f–5d transition optical spectrum of Tm2+ ions in SrCl2 shows good agreement with the corresponding experimental result.
Comparative glycomic profiling of isotopically permethylated N‐glycans by liquid chromatography/electrospray ionization mass spectrometry
Authors: Hu Yunli , Desantos‐Garcia Janie L. , Mechref Yehia 
Published: March 2013

RATIONALEMass spectrometry based comparative glycomics is essential for disease biomarker discovery. However, developing a reliable quantification method is still a challenging task.METHODSWe here report an isotopic labeling strategy employing stable isotopic iodomethane for comparative glycomic profiling by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS). N‐Glycans released from model glycoproteins and blood serum samples were permethylated with iodomethane ('light') and iodomethane‐d1 or ‐d3 ('heavy') reagents. Permethylated samples were then mixed at equal volumes prior to LC/ESI‐MS analysis.RESULTSPeak intensity ratios of N‐glycans isotopically permethylated (Heavy/Light, H/L) were almost equal to the theoretical values. Observed differences were mainly related to the purity of 'heavy' iodomethane reagents (iodomethane‐d1 or ‐d3). The data suggested the efficacy of this strategy to simultaneously quantify N‐glycans derived from biological samples representing different cohorts. Accordingly, this strategy is effective in comparing multiple samples in a single LC/ESI‐MS analysis. The potential of this strategy for defining glycomic differences in blood serum samples representing different esophageal diseases was explored.CONCLUSIONSLC/ESI‐MS comparative glycomic profiling of isotopically permethylated N‐glycans derived from biological samples and glycoproteins reliably defined glycan changes associated with biological conditions or glycoproteins expression. As a biological application, this strategy permitted the reliable quantification of glycomic changes associated with different esophageal diseases, including high grade dysplasia, Barrett's disease, and esophageal adenocarcinoma. Copyright © 2013 John Wiley & Sons, Ltd.
Collision‐induced dissociation studies of caffeine in positive electrospray ionisation mass spectrometry using six deuterated isotopomers and one N1‐ethylated homologue
Authors: Bier Dirk , Hartmann Rudolf , Holschbach Marcus 
Published: March 2013

RATIONALEIn order to deepen the understanding of electrospray ionisation collision‐induced dissociation (ESI‐CID) fragmentation reactions of xanthine derivatives for the identification of metabolites using low‐resolution liquid chromatography/mass spectrometry (LC/MS) analysis, basic experiments using caffeine (1,3,7‐trimethylxanthine) as model compound have been performed.METHODSSix deuterium isotopomers and one N1‐ethylated homologue of caffeine have been synthesized and their ESI fragmentation spectra have been obtained by using LC/MS in combination with either standard or perdeuterated eluent mixtures.RESULTSOne result of these studies is the finding that the positive charges of the ESI‐CID caffeine fragments are caused by the addition of protons. Furthermore, the performed experiments allow the determination of all molecular formulae of each ESI‐CID caffeine fragment.CONCLUSIONSAs basic CID reactions of caffeine have been elucidated in this work, the developed fragmentation scheme may serve as a valuable tool for the interpretation of ESI‐CID fragmentation spectra of more complex xanthine derivatives and their respective metabolites. Copyright © 2013 John Wiley & Sons, Ltd.