bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Co(II) in plant tissue by microwave digestion and ion chromatography coupled with luminol/perborate or luminol/percarbonate chemiluminescence detection
Authors: Murillo Pulgarín José A. , García Bermejo Luisa F. , Durán Armando Carrasquero 
Published: September 2010

AbstractIntroduction – The cobalt is an essential element for leguminous plants but may be harmful for other species; for that reason determination of Co(II) is very important for the management of polluted areas and for discover plants with capacity for the hyperaccumulation of heavy metals, which has produced a growing necessity of fast, sensitive and selective analytical techniques.Objective – To develop an analytical procedure for the determination of cobalt in plant tissue by coupling the ionic chromatography to the luminol‐based chemiluminescence detection.Methodology – The sample was digested in a mixture of concentrated nitric acid and hydrogen peroxide, using an microwave oven to dissolve the Co(II). The solution containing Co(II) ions was injected to an ionic chromatograph using oxalic acid as the eluent. The detection was based on the catalytic effect of Co(II) on the luminol chemiluminescence using perborate or percarbonate as oxidants. Experimental variables, such as concentrations, pH, flow rates and acid digestion conditions were optimised.Results – Well‐resolved chromatographic peaks were obtained. The height and area showed linear dependences with the Co(II) concentration, which were used to quantify the heavy metal, with recoveries up to 95%. The microwave irradiation (60 s) was sufficient for the complete mineralisation of 200 mg of sample, employing 2 mL of the acid mixture. The method was free from the interferences, requiring less than 12 minutes to complete the analysis.Conclusion – The method was simple and rapid for the determination of cobalt in plant tissue with detection limits comparable to those obtained with more sophisticated and expensive analytical equipments. Copyright © 2010 John Wiley & Sons, Ltd.
First‐trimester serum PAPP‐A and fβ‐hCG concentrations and other maternal characteristics to establish logistic regression‐based predictive rules for adverse pregnancy outcome
Authors: van Ravenswaaij R. , Tesselaar‐van der Goot M. , de Wolf S. , van Leeuwen‐Spruijt M. , Visser G. H. A. , Schielen P. C. J. I. 
Published: September 2010

AbstractObjectiveTo determine the clinical relevance of maternal characteristics and first‐trimester serum concentrations of pregnancy‐associated plasma protein A (PAPP‐A) and free beta human chorionic gonadotrophin (fβ‐hCG) in predicting placenta‐related complications, miscarriage and preterm delivery.Design, Setting and PopulationA historical cohort study of data of the National Institute for Public Health and the Environment of first‐trimester screening tests performed between July 2002 and May 2006 was done. Data from 28 566 (64.1%) tests were eligible for analysis.MethodsBy logistic regression, predictive rules were made based on PAPP‐A and fβ‐hCG concentrations, maternal smoking, maternal weight and age, low birth weight, stillbirth and hypertensive disorders, miscarriage and preterm birth. Predictive values were analysed with the area under the curve (AUC) of receiver operating curves (ROC).ResultsPredictive for placenta‐related complications were low PAPP‐A, low fβ‐hCG, smoking and weight (AUC 54%). For miscarriage low PAPP‐A, low fβ‐hCG and maternal age (MA) were predictive (AUC 78%) and for preterm delivery low PAPP‐A, smoking, MA and maternal weight (AUC 55%).ConclusionOnly the predictive model for miscarriage had a clinically relevant predictive value of 28%. Results together do not justify closer surveillance of chromosomally normal pregnancies with PAPP‐A or fβ‐hCG levels below the fifth percentile. Copyright © 2010 John Wiley & Sons, Ltd.
Elucidation of the avian nucleolar proteome by quantitative proteomics using SILAC and changes in cells infected with the coronavirus infectious bronchitis virus
Authors: Emmott Edward , Smith Catriona , Emmett Stevan R. , Dove Brian K. , Hiscox Julian A. 
Published: September 2010

AbstractThe nucleolus is a dynamic subnuclear compartment involved in ribosome subunit biogenesis, regulation of cell stress and modulation of cellular growth and the cell cycle, among other functions. The nucleolus is composed of complex protein/protein and protein/RNA interactions. It is a target of virus infection with many viral proteins being shown to localize to the nucleolus during infection. Perturbations to the structure of the nucleolus and its proteome have been predicted to play a role in both cellular and infectious disease. Stable isotope labeling with amino acids in cell culture coupled to LC‐MS/MS with bioinformatic analysis using Ingenuity Pathway Analysis was used to investigate whether the nucleolar proteome altered in virus‐infected cells. In this study, the avian nucleolar proteome was defined in the absence and presence of virus, in this case the positive strand RNA virus, avian coronavirus infectious bronchitis virus. Data sets, potential protein changes and the functional consequences of virus infection were validated using independent assays. These demonstrated that specific rather than generic changes occurred in the nucleolar proteome in infectious bronchitis virus‐infected cells.
The 2009 Human Liver Proteome Project (HLPP) Workshop 26 September 2009, Toronto, Canada
Authors: Gao Xue , Zheng Junjie , Beretta Laura , Mato Jose , He Fuchu 
Published: September 2010

AbstractThe Human Liver Proteome Project (HLPP) was formally launched by HUPO in 2002. The 11th HLPP Workshop was held on September 26th, 2009 during the 8th HUPO World Congress in Toronto, Canada. The representative progresses were presented from four groups. Subsequently, the workshop ended with a lively discussion on four topics related to the project as well as other initiatives.
Alcohol oxidation catalysed by Ru(VI) in the presence of alkaline hexacyanoferrate(III)
Authors: Poblete Francisco J. , Corrochano Pablo 
Published: September 2010

AbstractThe oxidation of sodium lactate, 2‐methyl‐2,4‐pentanediol, 2,4‐butanediol, 2‐butanol and 2‐propanol upon treatment with alkaline hexacyanoferrate(III) using a Ru(VI) catalyst is highly effective for the oxidation of alcohols by ${\rm Fe}({\rm CN})_{6}^{3{-} }$. The reaction mechanism proposed involves the oxidation of the alcohol by the catalyst, a process that occurs through the formation of a substrate‐catalyst complex. The decomposition of this complex yields Ru(IV) and a carbocation (owing to a hydride transfer from the α‐CH bond of the alcohol to the oxoligand of ruthenium). The role of the co‐oxidant, hexacyanoferrate(III), is to regenerate the catalyst. In the oxidation reactions, the rate constants for complex decomposition and catalyst regeneration have been determined and a comparative study of the structure versus reactivity has been carried out. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis of cationic diacetylene‐co‐carbazole‐co‐fluorene polymers and their sensitive fluorescent quenching properties with DNA
Authors: Zeng Wennan , Liu Shouping , Zou Hanxun , Wang Linyun , Beuerman Roger , Cao Derong 
Published: September 2010

AbstractTwo neutral precursor conjugated copolymers based 2,7‐diethynylfluorene and 3,6‐diethynylcarbazole units in the main chain (PFC and PF2C) were prepared by Hay coupling polymerization. Their cationic copolymers (CPFC and CPF2C) were prepared by the methylation of their diethylpropylamino groups with CH3I. For comparison, neutral conjugated homopolymers of 2,7‐diethynylfluorene (PF), 3,6‐diethynylcarbazole units (PC) and their cationic polymers (CPF and CPC) were also prepared with the same method. A comparative study on the optical properties of cationic polymers CPFC and CPF2C in DMF and DMF/H2O showed that they underwent water‐induced aggregation. The spectral behaviors of CPFC and CPF2C with calf thymus DNA showed that a distinct fluorescent quenching took place with minute addition of CT DNA (3.3 × 10−13 M). The results showed that the polymers would be promising biosensor materials for sensitive detection of DNA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4168–4177, 2010
Molecular weight and configurational stability of poly[(fluorophenyl)acetylene]s prepared with metathesis and insertion catalysts
Authors: Bondarev Dmitrij , Zedník Jiří , Plutnarová Iva , Vohlídal Jiří , Sedláček Jan 
Published: September 2010

AbstractSeries of high‐cis and cis/trans poly[(fluorophenyl)acetylene]s (PFPhA) have been prepared by polymerization of (2‐fluorophenyl)acetylene, (3‐fluorophenyl)acetylene, and (4‐fluorophenyl)acetylene with catalysts: [Rh(1,5‐cyclooctadiene) OCH3]2 (high‐cis PFPhAs) and tungsten(VI) oxychloride/tetraphenyltin (cis/trans PFPhAs). The molecular weight and configurational stability under various conditions at room temperature were studied for both PFPhAs series by means of size exclusion chromatography, 1H‐NMR, and UV‐vis techniques. All samples exhibited slow degradation when exposed to the atmosphere in the solid state; the rate of degradation was independent on the F‐position on the Ph ring. The rate of degradation increased up to three orders of magnitude in the tetrahydrofuran solution where it was higher for high‐cis polymers compared with their cis/trans counterparts. The degradation of high‐cis PFPhAs was accompanied by significant cis‐to‐trans isomerization in aerated tetrahydrofuran solution. Rate of degradation and isomerization exhibited the same dependence on the F‐position on the Ph ring. The hypothesis was postulated that the degradation of high‐cis PFPhAs in solution was accelerated by cis‐to‐trans isomerization due to which the content of unpaired electrons on the main chains is enhanced. In both high‐cis and cis/trans series of polymers the ortho‐substituted isomers exhibited an enhanced stability compared with meta‐ and para‐substituted isomers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4296–4309, 2010
Hybrid organo‐inorganic globular nanospecies: Transition from macromolecule to particle
Authors: Voronina N. V. , Meshkov I. B. , Myakushev V. D. , Laptinskaya T. V. , Papkov V. S. , Buzin M. I. , Il'ina M. N. , Ozerin A. N. , Muzafarov A. M. 
Published: September 2010

AbstractMolecular forms of silica based on polyethoxysiloxane, silicasol, and tetraethoxysilane, being prospective fillers for polymer nanocomposites were prepared and studied thoroughly by gel permeation chromatography (GPC), viscometry, dynamic light scattering (DLS), thermomechanics, and wide angle X‐ray scattering (WAXS). All synthesized objects were shown to possess the structure of “core ‐ shell” type. Particle radius varies in a range of 0.5–10 nm. The core structure depends on a method of preparation, while a particle morphology (share of core and shell) may be regulated within every of three methods. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4310–4322, 2010
Synthesis and characterization of novel methacrylate copolymers based on sulfonamide and coumarine: Monomer reactivity ratios, biological activity, thermal stability, and optical properties
Authors: Erol Ibrahim , Sanli Gülay , Dİlek Meltem , Ozcan Levent 
Published: September 2010

AbstractThe free radical copolymerization of 2‐oxo‐2‐[(4‐sulfamoylphenyl)amino]ethyl‐2‐methylpropenoate (SAEMA) with 4‐methyl‐2‐oxo‐2H‐chromen‐7‐yl‐2‐methylpropenoate (MCMA) has been carried out in 1, 4‐dioxane at 65 °C ± 1 °C and the copolymers were analyzed by Fourier‐transform infrared, 1H‐NMR, 13C‐NMR and gel permeation chromatography. 1H‐NMR and elemental analysis was used to determine the molar fractions of SAEMA and MCMA in the copolymers. The monomer‐reactivity ratios were calculated according to the general copolymerization equation using Kelen‐Tüdõs and Fineman‐Ross linearization methods. The reactivity ratios indicated a tendency toward random copolymerization. The polydispersity indices of the polymers, determined with gel permeation chromatography, suggested a strong tendency for chain termination by disproportionation. The thermal behaviors of copolymers with various compositions were investigated by differential scanning calorimetry and thermogravimetric analysis. The glass‐transition temperature of the copolymers increased with increasing MCMA content in the copolymers. Also, the apparent thermal decomposition activation energies were calculated by the Ozawa method with a Shimadzu TGA 60 thermogravimetric analysis thermobalance. All the products showed moderate activity against different strains of bacteria and fungi. The photochemical properties of the polymers were investigated by UV spectra. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4323–4334, 2010
Hydrophilic functionalization of syndiotactic polystyrene via a combination of electrophilic bromination and Suzuki–Miyaura reaction
Authors: Shin Jihoon , Chang Ying , Nguyen Thi Le Thanh , Noh Seok Kyun , Bae Chulsung 
Published: September 2010

AbstractPostfunctionalization of high‐molecular‐weight syndiotactic polystyrene (sPS) was achieved via combination of electrophilic bromination at the para‐position of the polymer aromatic ring and subsequent Suzuki–Miyaura cross‐coupling reactions with functionalized phenylboronic acids. The concentration of brominated styrene repeating unit in sPS was conveniently controlled by changing the ratio of added bromine relative to the polymer repeating unit. Brominated sPS (8.5 mol %) was converted quantitatively to other polar functional groups via Suzuki–Miyaura cross‐coupling reactions with various functional group‐substituted phenylboronic acids. The surface properties of functionalized sPS were studied by measuring water contact angles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4335–4343, 2010
Novel triarylamine‐based alternating conjugated polymer with high hole mobility: Synthesis, electro‐optical, and electronic properties
Authors: Chen Wen‐Hsiang , Wang Kun‐Li , Hung Wen‐Yi , Jiang Jyh‐Chiang , Liaw Der‐Jang , Lee Kueir‐Rarn , Lai Juin‐Yih , Chen Ci‐Liang 
Published: September 2010

AbstractNovel bi‐triphenylamine‐containing aromatic dibromide M3, N,N‐bis(4‐bromophenyl)‐N′,N′‐dipheny‐l,4‐phenylenediamine, was successfully synthesized. The novel conjugated polymer P1 having number‐average molecular weight of 1.31 × 104 was prepared via Suzuki coupling from the dibromide M3 and 9,9‐dioctylfluorene‐2,7‐diboronic acid bis(1,3‐propanediol) ester. Polymer P1 had excellent thermal stability associated with a high glass‐transition temperature (Tg = 141 °C). The hole‐transporting and UV‐vis‐near‐infrared electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the conjugated polymer films cast onto indium‐tin oxide‐coated glass substrates exhibited two reversible oxidation redox couples at E1/2 values of 0.73 and 1.13 V versus Ag/Ag+ in acetonitrile solution. The hole mobility of the conjugated polymer P1 revealed ∼10−3 cm2 V−1 s−1, which is much higher than that of other conjugated polymer systems. The observed UV‐vis‐near‐infrared absorption change in the conjugated polymer film P1 at applied potentials ranging from 0.00 to 1.23 V are fully reversible and associated with strong color changes from pale yellowish in its neutral form to green and blue in its oxidized form. Using a combination of experimental study and theoretical investigation, we proposed an oxidation mechanism based on molecular orbital theory, which explains the cyclic voltammetry experimental results well. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Photoinitiated alternating copolymerization of dialkyl maleates and fumarates with vinyl ethers
Authors: Crivello James V. , McGrath Thomas M. 
Published: September 2010

AbstractA systematic study of the free radical photoinitiated alternating crosslinking copolymerizations of dialkyl maleates and furmarates with multifunctional vinyl ethers was carried out. The photocopolymerizations were fast and highly efficient when carried out using a variety of α‐cleavage photoinitiators. The effects of the structures of the both the unsaturated esters and the vinyl ether monomers were examined. Dialkyl maleates were observed to be more reactive than the corresponding fumarate esters. The photopolymerization rates of several of these comonomer pairs were compared with standard diacrylate and dimethacrylate monomers. A range of different physical properties can be obtained by varying the length of the alkyl chain on alcohol portion of the unsaturated ester monomer. Prospects for the use of these comonomer systems in UV curable coatings, adhesives, printing inks, and composites are discussed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Preparation of highcis‐1,4 polyisoprene with narrow molecular weight distribution via coordinative chain transfer polymerization
Authors: Fan Changliang , Bai Chenxi , Cai Hongguang , Dai Quanquan , Zhang Xuequan , Wang Fosong 
Published: September 2010

AbstractHighcis‐1,4 polyisoprene with narrow molecular weight distribution has been prepared via coordinative chain transfer polymerization (CCTP) using a homogeneous rare earth catalyst composed of neodymium versatate (Nd(vers)3), dimethyldichlorosilane (Me2SiCl2), and diisobutylaluminum hydride (Al(i‐Bu)2H) which has strong chain transfer affinity is used as both cocatalyst and chain transfer agent (CTA). Differentiating from the typical chain shuttling polymerization where dual‐catalysts/CSA system has been used, one catalyst/CTA system is used in this work, and the growing chain swapping between the identical active sites leads to the formation of highcis‐1,4 polyisoprene with narrowly distributed molecular weight. Sequential polymerization proves that irreversible chain termination reactions are negligible. Much smaller molecular weight of polymer obtained than that of stoichiometrically calculated illuminates that, differentiating from the typical living polymerization, several polymer chains can be produced by one neodymium atom. The effectiveness of Al(i‐Bu)2H as a CTA is further testified by much broad molecular weight distribution of polymer when triisobutylaluminum (Al(i‐Bu)3), a much weaker chain transfer agent, is used as cocatalyst instead of Al(i‐Bu)2H. Finally, CCTP polymerization mechanism is validated by continuously decreasedMw/Mnvalue of polymer when increasing concentration of Al(i‐Bu)2H extra added in the Nd(ver)3/Me2SiCl2/Al(i‐Bu)3catalyst system. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Proton‐conductive polymer nanocomposite membranes prepared from telechelic fluorinated polymers containing perfluorosulfonic acid side chains
Authors: Chanthad Chalathorn , Xu Kui , Huang He , Wang Qing 
Published: September 2010

AbstractNew classes of fluorinated polymer–polysilsesquioxane nanocomposites have been designed and synthesized. The synthesis method includes radical polymerization using the functional benzoyl peroxide initiator for the telechelic fluorinated polymers with perfluorosulfonic acids in the side chains and a subsequent in situ sol–gel condensation of the prepared triethoxylsilane‐terminated fluorinated polymers with oxide precursors. The telechelic polymer and nanocomposites have been carefully characterized by 1H and 19F NMR, FTIR, TGA, and TEM. The ion‐exchange capacity (IEC), water uptake, the state of the absorbed water, and transport properties of the composite membranes have been extensively studied as a function of the content and structure of the fillers. Unlike the conventional Nafion/silica composites, the proton conductivity of the prepared membranes increases steadily with the addition of small amounts of the polysilsesquioxane fillers. In particular, the sulfopropylated polysilsesquioxane‐based nanocomposites display proton conductivities greater than Nafion. This is attributed to the presence of pendant sulfonic acids in the fillers, which increases IEC and offers continuous proton transport channels between the fillers and the polymer matrix. The methanol permeability of the prepared membranes has also been examined. Lower methanol permeability and higher electrochemical selectivity than those of Nafion have been demonstrated in the polysilsesquioxane‐based nanocomposites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Energy diagrams and stability restrictions for electroelastic generators
Authors: Díaz‐Calleja Ricardo , Llovera‐Segovia Pedro 
Published: September 2010

AbstractThe relation between electric and mechanical properties of dielectric elastomers allows using them as energy convertors under some conditions. The process is based on the relations between mechanical and electrical energy stored on the material. In this work, cycles of maximal mechanical energy to be converted into electrical energy are presented. The purpose of this article is to give a general formulation of electroelastic generator relations considering (1) Mooney‐Rivlin materials, (2) floating sample between electrodes and sample with compliant electrodes, and (3) explicit thermodynamic stability criteria. Estimations on the maximal energy to be converted are made. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2023–2028, 2010
Conductive and optical properties of PPV modified by N+ ion implantation
Authors: Li Baoming , Cheng Lei , Zheng Yuying 
Published: September 2010

AbstractIn this article, a soluble poly[2‐methoxy‐5‐(3′‐methyl)butoxy]‐p‐phenylene vinylene (MMB‐PPV) was synthesized by dehydrochlorination reaction and the MMB‐PPV film was implanted by nitrogen ions (N+) with the ion dose and energy in the range of 3.8 × 1015 to 9.6 × 1016 ions/cm2 and 15–35 keV, respectively. The surface conductivity, optical absorption, optical band gap (Eg) of modified MMB‐PPV film were studied, and the third‐order nonlinear optical susceptibility (χ(3)) as well as its environmental stability of modified MMB‐PPV film were also measured by degenerate four‐wave mixing system. The results showed that the surface conductivity of MMB‐PPV film was up to 3.2 × 10−2 S when ion implantation was performed with the energy of 35 keV at an ion dose of 9.6 × 1016 ions/cm2, which was seven order of magnitude higher than that of the pristine film. UV‐Vis absorption spectra demonstrated that the optical absorption of MMB‐PPV film was enhanced gradually in the visible region followed by a red shift of optical absorption threshold and the Eg value was reduced from 2.12 eV to 1.59 eV with the increase of ion dose and energy. The maximum χ(3) value of 2.45 × 10−8 esu for modified MMB‐PPV film was obtained with the ion energy of 20 keV at an ion dose of 3.8 × 1016 ions/cm2, which was almost 33 times larger than that for pristine film. In comparison to the reduction of 17% in the χ(3) value of pristine MMB‐PPV film, the maximum χ(3) value of 2.45 × 10−8 esu for modified MMB‐PPV film decreased by over 5.3% when they had been exposed under the same ambient conditions for 90 days. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2072–2077, 2010