bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection rate of quadruple‐marker screening determined by clinical follow‐up and registry data in the statewide California program, July 2007 to February 2009
Authors: Kazerouni Niloufar Neely , Currier Robert J. , Flessel Monica , Goldman Sara , Hennigan Colin , Hodgkinson Christina , Lorey Fred , Malm Linda , Tempelis Corinna , Roberson Marie 
Published: June 2011

AbstractObjectiveTo evaluate the efficiency of California's quadruple‐marker screening program and construct receiver‐operating characteristic (ROC) curves.MethodsThis study included the screening records of 552 941 women during July 2007 to February 2009. The screen‐positive women received clinical follow‐up services at state‐approved centers. We used the California Chromosome Defect Registry which includes clinical, laboratory, and demographic data from the prenatal diagnostic centers, cytogenetic laboratories, hospitals, and prenatal care providers. Risk calculations, screen‐positive rates (SPRs), detection rates (DRs) for chromosomal abnormalities, and 95% confidence intervals (95% CIs) were determined. ROC curves comparing the quadruple‐marker to triple‐marker screening were constructed.ResultsThe DR and SPR for trisomy 21 (N = 827) during the quadruple‐marker time period were 75.7% (95% CI 72.8–78.6%) and 3.75% (95% CI 3.70–3.80%) compared with 77.4% (95% CI 75.0–79.7%) and 5.4% during the triple‐marker phase. The DRs were 78.2% (95% CI 75.0–81.4%) with ultrasound dating and 66.9% (95% CI 59.7–74.0%) for last‐menstrual‐period‐dated pregnancies. For trisomy 18, triploidy, and trisomy 13, the DRs were 84.3, 95.7, and 43.5%, respectively.ConclusionsThe DR for trisomy 21 in California's statewide quadruple‐marker screening is very similar to the Program's previously reported DR using triple‐marker screening. However, this was achieved at a lower SPR, demonstrating improved screening performance. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis and post‐polymerization modification of maleimide‐containing polymers by ‘thiol‐ene’ click and Diels–Alder chemistries
Authors: Hall Daniel J. , Van Den Berghe Helene M. , Dove Andrew P. 
Published: June 2011

AbstractThis mini‐review provides an introduction to the key work in the area of synthesis and post‐polymerization functionalization of maleimide‐functional polymers. The versatility and utility of the maleimide group in the efficient functionalization of polymers by both ‘thiol‐ene’ Michael addition and Diels–Alder cycloaddition chemistries are highlighted. Copyright © 2011 Society of Chemical Industry
Structural investigations and swelling behavior of 6FDA copolyimide thin films
Authors: Konietzny Roman , Barth Christoph , Harms Stephan , Raetzke Klaus , Koelsch Patrick , Staudt Claudia 
Published: June 2011

AbstractThe effects of swelling on chain distance, free volume size and orientation of functional groups of copolyimides containing carboxyl groups were examined using wide‐angle X‐ray diffraction (WAXD), positron annihilation lifetime spectroscopy (PALS) and Fourier transform infrared (FTIR) spectroscopy. A 2,3‐dimethylbenzothiophene/n‐dodecane mixture (0.3 wt%/99.7 wt%) was used as a swelling agent, as it is a binary model mixture to investigate membrane‐based desulfurization of kerosene. Thin film samples were prepared from copolyimide structures which had been synthesized via a polycondensation reaction of 4,4′‐hexafluoroisopropylidene di(phthalic anhydride), 3,5‐diaminobenzoic acid, 2,3,5,6‐tetramethyl‐1,4‐phenylenediamine and 2,4,6‐trimethyl‐1,3‐phenylenediamine. A relationship between a lower amount of 3,5‐diaminobenzoic acid present in the copolyimide backbone and a higher amount of solvent sorption in the film was found. This was attributed to the fact that the carboxyl groups on the polymer backbone can form hydrogen bonds, reducing sorption and swelling phenomena. PALS measurements for the different structures showed significantly smaller hole sizes for the free volume sites of the copolyimide containing fewer carboxyl groups. Although WAXD of film samples after time‐dependent swelling indicated that the chain distance initially decreased slightly, FTIR experiments using polarized light did not show any significant orientation changes in the polymer chains. Copyright © 2011 Society of Chemical Industry
Influence of reactive compatibilization on the structure and properties of PP/LDH nanocomposites
Authors: Lonkar Sunil P. , Therias Sandrine , Leroux Fabrice , Gardette Jean Luc , Singh Raj Pal 
Published: June 2011

AbstractPolypropylene (PP)/layered double hydroxide (LDH) nanocomposites were prepared by the direct melt intercalation method using maleic anhydride grafted polypropylene (PP‐g‐MAH) as a reactive compatibilizer. The compatibilization effects provided by PP‐g‐MAH in different weight fractions and their influence on the structure and properties of the final nanocomposites were investigated. The interactions and structural morphology of the nanocomposites were examined by Fourier transform infrared spectroscopy, X‐ray diffraction and transmission electron microscopy. Thermal, mechanical and rheological properties of these nanocomposites were investigated as a function of compatibilizer concentration. The detailed morphological and X‐ray diffraction results revealed that the degree of LDH dispersion increases as the amount of PP‐g‐MAH increases. Study of the linear viscoelastic properties showed that the storage modulus G′ is very sensitive to the microstructure of the nanocomposite. The thermal properties of the nanocomposites were significantly influenced by the weight fraction of PP‐g‐MAH due to the shielding and nucleating effect of exfoliated layers. Both the tensile strength and modulus showed substantial improvements with increasing PP‐g‐MAH content, while the elongation at break substantially decreased, although the presence of PP‐g‐MAH somewhat improves these values. The overall results showed that 10 wt% of compatibilizer is optimum to achieve nanocomposites with better performance. Copyright © 2011 Society of Chemical Industry
Toughening of poly(propylene carbonate) by hyperbranched poly(ester‐amide) via hydrogen bonding interaction
Authors: Chen Lijie , Qin Yusheng , Wang Xianhong , Li Yuesheng , Zhao Xiaojiang , Wang Fosong 
Published: June 2011

AbstractPoly(propylene carbonate) (PPC) is a biodegradable alternative copolymer of propylene oxide and carbon dioxide. As an amorphous polymer with lower glass transition temperature around 35 °C, PPC shows poor mechanical performance in that it becomes brittle below 20 °C and its dimensional stability deteriorates above 40 °C; thus toughening of PPC is urgently needed. Here we describe a biodegradable hyperbranched poly(ester‐amide) (HBP) that is suitable for this purpose. Compared with pure PPC, the PPC/HBP blend with 2.5 wt% HBP loading showed a 51 °C increase in thermal decomposition temperature and a 100% increase in elongation at break, whilst the corresponding tensile strength remained as high as 45 MPa and tensile modulus showed no obvious decrease. Crazing as well as cavitation was observed in the scanning electron microscopy images of the blends, which provided good evidence for the toughening mechanism of PPC. The intermolecular hydrogen bonding interaction confirmed by Fourier transform infrared spectral analysis proved to be the reason for the toughening phenomenon. Copyright © 2011 Society of Chemical Industry
Preparation of polybutene‐1/multiwall carbon nanotube composite by oxidation and limonene radical grafting and its characterization
Authors: Nakatani Hisayuki , Ogura Masashi , Yoshikawa Takanori , Miyazaki Kensuke , Okazaki Noriyasu , Terano Minoru 
Published: June 2011

AbstractIn this study, a novel preparation of a polybutene‐1 (PB) and multiwall carbon nanotube (MWNT) composite was achieved by a combination of PB autooxidation and a radical grafting reaction using an Nd2O3/dicumyl peroxide (DCP) radical initiator system with limonene. The autooxidation worked as an amplifier to produce more alkyl radical species in the grafting reaction, and the existence of the MWNTs and the limonene suppressed the side reaction. In addition, the existence of the limonene suppressed the oxidation of the MWNT surface. The composite obtained was assessed in comparison with a PB/MWNT composite and a composite of PB/MWNT modified by Nd2O3/DCP without limonene using some spectroscopic methods, optical and electron microscopes, a thermal analyzer and tensile testing. The novel preparation produced a well dispersed nanocomposite compared with the other preparations. The modified MWNT surface was tightly linked to the PB matrix, so that the tensile properties of the composite showed a dependence on MWNT content. Copyright © 2011 Society of Chemical Industry
Upper critical solution temperature switchable micelles based on polystyrene‐block‐poly(methyl acrylate) block copolymers
Authors: Can Aydin , Hoeppener Stephanie , Guillet Pierre , Gohy Jean‐François , Hoogenboom Richard , Schubert Ulrich S. 
Published: June 2011

AbstractThe solubility behavior of well‐defined poly(methyl acrylate) homopolymers as well as polystyrene‐block‐poly (methyl acrylate) block copolymers is discussed in this contribution. A solubility screening in ethanol–water solvent mixtures was performed in a high‐throughput manner using parallel turbidimetry revealing upper critical solution temperature behavior for poly(methyl acrylate). Moreover, the self‐assembly behavior of the block copolymers into micellar structures was investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM), andcryo‐TEM revealing upper critical solution temperature switchability of the micelles, which was evaluated by DLS at different temperatures. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Poly(acrylic acid) is a common noncompetitive inhibitor for cationic enzymes with high affinity and reversibility
Authors: Tomita Shunsuke , Shiraki Kentaro 
Published: June 2011

AbstractWe have recently developed a versatile technique, complementary polymer pair system (CPPS), which enables switching the activity of diverse enzymes using anionic poly (acrylic acid) (PAAc) and cationic poly(allylamine) (PAA). To obtain a deeper understanding of CPPS, we investigated the manner by which PAAc inhibits cationic ribonuclease A, lysozyme, and trypsin. Studies of the enzyme kinetics showed that PAAc acts as a noncompetitive inhibitor for all these enzymes, and carries several potent enzyme binding sites (Ki ≈ 10−8 M). In addition, the inhibited enzymes were recovered by oppositely charged PAA. These data indicate the generality of CPPS, as only the surface charge and not the substrate binding site of the enzymes should be considered when determining a charged polymer as an inhibitor. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis and photovoltaic properties of two‐dimensional D‐A copolymers with conjugated side chains
Authors: Chen Dugang , Yang Yang , Zhong Cheng , Yi Zhengran , Wu Fei , Qu Li , Li Yu , Li Yongfang , Qin Jingui 
Published: June 2011

AbstractFour novel two‐dimensional (2D) donor–acceptor (D‐A) type copolymers with different conjugated side chains, P1, P2, P3, and P4 (see Fig. 1), are designed and synthesized for the application as donor materials in polymer solar cells (PSCs). To the best of our knowledge, there were few reports to systematically study such 2D polymers with D‐A type main chains in this area. The optical energy band gaps are about 2.0 eV for P1–P3 and 1.67 eV for P4. PSC devices using P1–P4 as donor and [6,6]‐phenyl‐C61‐butyric acid methyl ester as acceptor in a weight ratio of 1:3 were fabricated and characterized to investigate the photovoltaic properties of the polymers. Under AM 1.5 G, 100 mA/cm2 illumination, a high open‐circuit voltage (Voc) of 0.9 V was recorded for P3‐based device due to its low HOMO level, and moderate fill factor was obtained with the best value of 58.6% for P4‐based device, which may mainly be the result of the high hole mobility of the polymers (up to 1.82 × 10−3 cm2/V s). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of novel copolymers obtained from acceptor/donor radical copolymerization of phosphonated allyl monomers and maleic anhydride
Authors: Negrell‐Guirao C. , David G. , Boutevin B. , Chougrani K. 
Published: June 2011

AbstractA series of four phosphonated‐bearing allyl monomers, that is, diethyl‐1‐allylphosphonate (AP), dimethyl‐1‐allyloxymethylphosphonate (AOP), 5‐ethyl‐5‐(allyloxymethyl)‐2‐oxo‐1,3,2‐dioxaphosphorinane (AEDPH), and 2‐benzyl‐5‐ethyl‐5‐(allyloxymethyl)‐2‐oxo‐1,3,2‐dioxaphosphorinane (AEDPBn) were synthesized. These monomers were then copolymerized by free radical polymerization in the presence of maleic anhydride, thus leading to alternated copolymers with phosphonate moieties. It was shown that both monomer conversion and reaction rate were dependent on the phosphonate moieties carried out by the allyl monomer: the bulkier the phosphonate group, the higher the polymerization rate. Thermogravimetric analysis of the copolymers revealed a high content of residue, also varying with the nature of the phosphonate moieties. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Covalent surface functionalization of multiwalled carbon nanotubes through bergman cyclization of enediyne‐containing dendrimers
Authors: Ma Jianguo , Deng Sheng , Cheng Xin , Wei Wei , Hu Aiguo 
Published: June 2011

AbstractA method for covalent functionalization of multiwalled carbon nanotubes (MWCNTs) was developed using the free radicals generated through Bergman cyclization of enediyne‐containing compounds. Four enediyne‐bearing Frechet type dendrimers were synthesized in good quantities and characterized. Then, the enediyne‐containing molecules were reacted with MWCNTs in N‐methyl‐2‐pyrrolidinone at 206 °C under nitrogen. The structure and morphology of the resulting products were characterized by thermogravimetric analysis, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and transmission electron microscopy. The dendrimer‐functionalized MWCNTs showed good solubility/dispersibility in common organic solvents and polymer solutions. They were used in the formation of polymer composites through electrospinning with polycaprolactone. The results confirmed the surface functionalization of MWCNTs. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Influence of nanoparticle surface chemistry on the thermomechanical and magnetic properties of ferromagnetic nanocomposites
Authors: Cruz‐Montoya Edwin De La , Rinaldi Carlos 
Published: June 2011

AbstractThe effect of nanoparticle surface chemistry on the thermal, mechanical, and magnetic properties of poly(methyl methacrylate) (PMMA) nanocomposites with cobalt ferrite nanofillers was studied by comparing nanofillers coated with oleic acid (OA; which does not covalently bond to the PMMA matrix) and 3‐methacryloxypropyltrimethoxysilane (MPS, which covalently bonds to the PMMA matrix). Thermogravimetric analysis revealed an increase in the thermal degradation temperature of the nanocomposites compared with the neat polymer. The effect of cobalt ferrite nanofiller on the glass transition temperature (Tg) of the nanocomposite was evaluated by differential scanning calorimetry. The Tg value of the material increased when the particles were introduced. Dynamic mechanical analysis indicated an increase in the storage modulus of the nanocomposite because of the presence of nanofiller and a shift in the peak of loss tangent toward higher temperature. Magnetic measurements indicated that both nanocomposites had a small hysteresis loop at 300 K and no hysteresis at 400 K. However, estimates of the nanofiller's rotational relaxation times and measurements of the zero field cooled temperature‐dependent magnetization indicate that the observed lack of hysteresis at 400 K is likely because of particle rotation in the polymer matrix. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Water absorption in polyaniline emeraldine base
Authors: Canales Manel , Aradilla David , Alemán Carlos 
Published: June 2011

AbstractAtomistic classical molecular dynamics simulations have been used to investigate the water absorption behavior of polyaniline emeraldine base. Results derived from simulations, which were performed considering polymeric systems with different concentrations of water (3%, 10%, 15%, 20%, 50%, and 100% w/w), have been compared with experimental evidences obtained for both powder and films. Calculation of the Hildebrand solubility parameters explains not only the insolubility of polyaniline in water but also the requirements, in terms of intermolecular interactions, needed by solvents to be compatibles with this polymer. The maximum content of absorbed water predicted for hygroscopic polyaniline is 15% w/w. The effects of the absorbed water in both the organization and conformation of the polymer chains have been examined at the microscopic level by analyzing the microstructures derived from simulations, while the role of the moisture in the morphology of powder and film samples has been investigated using atomic force microscopy. The overall of the results provides a complete and understandable view of the polyaniline·water interactions, and explains the influence of the water molecules in the structural properties of the polymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1322–1331, 2011
Block copolymer strategies for solar cell technology
Authors: Topham Paul D. , Parnell Andrew J. , Hiorns Roger C. 
Published: June 2011

AbstractA simple overview of the methods used and the expected benefits of block copolymers in organic photovoltaic devices is given in this review. The description of the photovoltaic process makes it clear how the detailed self‐assembly properties of block copolymers can be exploited. Organic photovoltaic technology, an inexpensive, clean and renewable energy source, is an extremely promising option for replacing fossil fuels. It is expected to deliver printable devices processed on flexible substrates using high‐volume techniques. Such devices, however, currently lack the long‐term stability and efficiency to allow organic photovoltaics to surpass current technologies. Block copolymers are envisaged to help overcome these obstacles because of their long term structural stability and their solid‐state morphology being of the appropriate dimensions to efficiently perform charge collection and transfer to electrodes. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Phase transformation and enhancement of toughness in polyvinylidene fluoride by onium salts
Authors: Vijayakumar R. P. , Khakhar Devang V. , Misra Ashok 
Published: June 2011

AbstractWe study the effect of onium salts (benzyl triphenyl phosphonium chloride, BTPC; tetrabutyl ammonium perchlorate, TAP) on the crystallization of polyvinylidene fluoride (PVDF) from a melt. The β phase of PVDF crystals is polar and has excellent piezoelectric properties, in contrast to the nonpolar α phase. Processing of PVDF results in the formation of predominantly α‐phase crystals. Different amounts of the onium salts were melt‐mixed into PVDF using a micro‐compounder. PVDF containing about 0.5 wt % of BTPC is found to have predominantly β‐phase crystals in compression molded PVDF films, with an increase in the melting temperature by about 7 °C. A significant increase in the toughness of PVDF is obtained by the addition of BTPC. Polarizing microscopy indicates that the onium salts act as nucleating agents and result in significant reduction in spherulite size. Similar results were observed for samples prepared with TAP. The results of the study indicate a facile method for producing β‐phase PVDF films. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1339–1344, 2011
Microwave ECR Plasma Assisted MOCVD of Y2O3 Thin Films Using Y(tod)3 Precursor and Their Characterization
Authors: Barve Shruti , Deo Mukul , Kar Rajib , Sreenivasan Nimisha , Kishore Ramaswamy , Biswas Arup , Bhanage Bhalchandra , Rao Mohan , Gantayet Lalit Mohan , Patil Dinkar 
Published: June 2011

AbstractYttrium oxide (Y2O3) thin films were deposited by microwave electron cyclotron resonance (ECR) plasma assisted metal organic chemical vapour deposition (MOCVD) process using indigenously developed metal organic precursors Yttrium 2,7,7‐trimethyl‐3,5‐octanedionates, commonly known as Y(tod)3 which were synthesized by an ultrasound method. A series of thin films were deposited by varying the oxygen flow rate from 1–9 sccm, keeping all other parameters constant. The deposited coatings were characterized by X‐ray photoelectron spectroscopy, glancing angle X‐ray diffraction and infrared spectroscopy. Thickness and roughness for the films were measured by stylus profilometry. Optical properties of the coatings were studied by the spectroscopic ellipsometry. Hardness and elastic modulus of the films were measured by nanoindentation technique. Being that microwave ECR CVD process is operating‐pressure‐sensitive, optimum oxygen activity is very essential for a fixed flow rate of precursor, in order to get a single phase cubic yttrium oxide in the films. To the best of our knowledge, this is the first effort that describes the use of Y(tod)3 precursor for deposition of Y2O3 films using plasma assisted CVD process. magnified image
What could hemoptysis hide in an otherwise healthy child?
Authors: Nenna Raffaella , Papoff Paola , Moretti Corrado , Cangiano Giulia , Ferro Valentina , Salvadei Serena , Soda Giuseppe , Mennini Maurizio , Midulla Fabio 
Published: June 2011

AbstractWe describe a previously healthy 12‐year‐old boy who attended our Department after a sudden episode of hemoptysis and recurrent consolidation. CT‐scan revealed a mediastinal tumor. The biopsy specimens taken from the mass showed a mature teratoma. Hemoptysis is an unusual presenting symptom in an otherwise healthy child with a well capsulated, unruptured mature mediastinal teratoma. In this report, hemoptysis prompted us to undertake the diagnostic work‐up that eventually disclosed the tumor. Pediatr. Pulmonol. 2011; 46:1146–1148. © 2011 Wiley Periodicals, Inc.
Validation of a school‐based written questionnaire for asthma case identification in Argentina
Authors: Busi Luciano E. , Sly Peter D. , Restuccia Sebastián , Llancamán Lidia 
Published: June 2011

AbstractRecognition of asthma in community‐based surveys can be problematic. We sought to develop and validate questionnaires that could identify elementary school‐aged children likely to have asthma or who had poorly‐controlled asthma. Questionnaires for parents (PQ) and students (SQ) to complete were developed using guidance on question wording from a focus group consisting of children with asthma and their parents. The gold standard for this study was a pulmonologist determination of asthma and this was used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for each question and for combinations of questions. Questionnaires were distributed to 830 children attending elementary schools in Trelew, Argentina and 96% were returned. Test–retest reliability was determined in 221 randomly selected parents and children and very good levels of agreement were seen for individual questions. Asthma was diagnosed in 92 students. Overall, the PQ was able to detect asthma better than the SQ. Optimal diagnostic ability came by combining questions from the PQ and SQ. Not surprisingly, these questionnaires had a better NPV than PPV and can be used to determine which children require further evaluation. Pediatr Pulmonol. Pediatr Pulmonol. 2012; 47:1–7. © 2010 Wiley Periodicals, Inc.