bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ethylene Homo‐ and Copolymerization Using a Bis‐IndZrCl2 Metallocene Catalyst: Structural Composition Distribution of the Copolymer
Authors: Mortazavi Mohammadmehdi , Arabi Hassan , Zohuri Gholam Hossein , Ahmadjo Saeid , Nekoomanesh Mehdi , Ahmadi Mostafa 
Published: June 2009

AbstractA bis‐IndZrCl2 catalyst was synthesized and used for ethylene homo‐ and copolymerization. The activity of the catalyst increases with increasing Al/Zr ratio; optimum activity was reached at 60 °C. $\overline M _{\rm v}$ of the polymer decreased as the polymerization temperature increased; increasing reaction pressure increased both $\overline M _{\rm v}$ and catalyst activity. The copolymerization of ethylene with different α‐olefins was studied using the same catalyst system. The results indicate that under identical conditions there was a general decrease in the rate of polymerization as compared to the homopolymerization. The CCD and the lamellar thickness were investigated using DSC. The heterogeneity of the CCD increased with increasing comonomer content and molar mass.magnified image
‘All singing from the same hymn sheet’: Healthcare professionals' perceptions of developing patient education material about the cardiovascular aspects of rheumatoid arthritis
Authors: John Holly , Hale Elizabeth D. , Treharne Gareth J. , Carroll Douglas , Kitas George D. 
Published: June 2009

AbstractObjective: Cardiovascular disease (CVD) is the leading cause of death in Britain, and its prevention is a priority. Rheumatoid arthritis (RA) patients have an increased risk of CVD, and management of modifiable classical risk factors requires a programme with patient education at its heart. Before a programme for RA patients is implemented, it is important to explore the perceptions of patients and relevant healthcare professionals and consider how these could influence the subsequent content, timing and delivery of such education. Here, we assess healthcare professionals' perceptions.Methods: Qualitative focus group methodology was adopted. Four group meetings of healthcare professionals were held using a semi‐structured interview schedule. The focus group transcripts were analysed using interpretative phenomenological analysis.Results: Three superordinate themes emerged: professional determinations about people with RA, including their perceptions about patients' priorities and motivations; communication about CVD risk, including what should be communicated, how, to whom and when; and responsibility for CVD management, referring to patients and the healthcare community.Conclusions: Although healthcare professionals agree that it is important to convey the increased CVD risk to patients with RA, there is concern they may be less proactive in promoting risk management strategies. There was uncertainty about the best time to discuss CVD with RA patients. Maintaining a close relationship between primary and secondary care was thought to be important, with all healthcare professionals ‘singing from the same hymn sheet’. These findings can inform the development of novel education material to fulfil a currently unmet clinical need. Copyright © 2009 John Wiley & Sons, Ltd.
Multiple bone tuberculosis in a child from predynastic Upper Egypt (3200 BC)
Authors: Dabernat H. , Crubézy É. 
Published: June 2009

AbstractTuberculosis, one of the most ancient human diseases, was present in ancient Egypt and has been observed since predynastic times. Excavations in the predynastic to early dynastic necropolis of Adaima, Upper Egypt (3500–2700 BC) led to the discovery of a number of remarkably well‐preserved skeletons of children. The skeletal remains of a 4.5–5‐year‐old child dated from Nagada III A2 (3200–3100 BC) displayed various lesions on the post‐cranial skeleton: spondylitis on the thoracic (T12) and lumbar (L1) vertebrae, partial lytic destruction of the right radio‐ulnar joint, lytic lesions on the scapula and a clavicle, dactylitis on the short bones of hands and feet, enlargement (spina ventosa) and periosteal new bone formation on the long bones. Radiographs show well‐defined radiolucent (cyst‐like) lesions in the metaphysis and the diaphysis of long tubular bones (ulna, radius, femur, tibia, fibula). The lesions recorded during macroscopic and radiological analysis strongly suggest a case of multiple bone tuberculosis. The occurrence of this case of tuberculosis in a child provides a picture of a period where tuberculosis must have been endemic throughout the population living during the origins of urban settlement in Upper Egypt during the predynastic period. Copyright © 2009 John Wiley & Sons, Ltd.
A review of bilateral training for upper extremity hemiparesis
Authors: Stoykov Mary Ellen , Corcos Daniel M. 
Published: June 2009

AbstractUpper extremity hemiparesis is the most common post‐stroke disability. Longitudinal studies have indicated that 30–66% of stroke survivors do not have full arm function 6 months post‐stroke. The current gold standard for treatment of mild post‐stroke upper limb impairment is constraint‐induced therapy but, because of the inclusion criteria, alternative treatments are needed which target more impaired subjects. Bilateral arm training has been investigated as a potential rehabilitation intervention. Bilateral arm training encompasses a number of methods including: (1) bilateral isokinematic training; (2) mirror therapy using bilateral training; (3) device‐driven bilateral training; and (4) bilateral motor priming. Neural mechanisms mediating bilateral training are first reviewed. The key bilateral training studies that have demonstrated evidence of efficacy will then be discussed. Finally, conclusions are drawn concerning clinical implications based on the reviewed literature. Copyright © 2009 John Wiley & Sons, Ltd.
Preparation of poly(3, 4‐ethylenedioxythiophene)/poly(styrene sulfonate) (PEDT/PSS) composite and its applications in anti‐static coating
Authors: Qiu Chunchang , Wang Jikui , Mao Shuangming , Guo Weihong , Cheng Shujun , Wang Yaoxian 
Published: June 2009

AbstractPoly(3, 4‐ethylenedioxythiophene)/poly(styrene sulfonate) (PEDT/PSS) composite is prepared by solution polymerization at room temperature in the presence of 3, 4‐ethylenedioxythiophene as the monomer, PSS as the doping agent, potassium supersulfate (KPS) as the oxidant, and deionized water as the solvent. The color of the PEDT/PSS solution is dark blue and its solid content is 2.2%, its pH value is 1.5. By mixing alcohols, polar organic solvents, adhesives, and so on into PEDT/PSS solution, the anti‐static coating solution is prepared. The coating is conducted by bar‐coating (20 µm) at 40% relative humidity and 20°C. The influence of the content of each component on the coating surface resistivity is discussed, and a reasonable volume content of each component is obtained. The obtained coating has low surface resistivity (1 × 106 Ω), excellent water resistance, and high transmittance of visible light together with a wide range of potential applications. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of monomer structures on the foaming processes and thermal properties of polyimide foams
Authors: Shen Yan‐Xia , Zhan Mao‐Sheng , Wang Kai 
Published: June 2009

AbstractFour polyimide (PI) foams were prepared from polyamide acid precursors. The effects of monomer structures on the foaming processes and thermal properties of PI foams were investigated. The foaming processes of PI foams were observed by a self‐made visualization device. The thermal properties of four PI foams were studied by the methods of dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetry/differential thermogravimetry (TG/DTG) analysis. The results indicated that the inflation onset temperatures and maximum inflation degrees of four precursors increased from 123 to 171°C and decreased from 28 to 15 times with the increasing rigidity of the precursor molecule, respectively. The glass transition temperatures, the 5% weight loss temperatures, the decomposed activation energies, and pre‐exponential factors of PI foams increased with increase in the rigidity of monomer. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of temperature on the electrical resistivity of YBa2Cu3O7−x/polyethylene composite materials
Authors: Bhadrakumari S. , Predeep P. 
Published: June 2009

AbstractHeterogeneous materials composed of conducting YBa2Cu3O7−x particles randomly dispersed inside an insulating low density polyethylene (LDPE) matrix were prepared. The resistivity of the composites was measured as a function of temperature between 293 and 400 K. A large positive temperature coefficient (PTC) of resistance was observed near 395 K. The mechanism of the PTC effect in the materials is related to the percolation behavior of the YBa2Cu3O7−x/LDPE composites and the thermal expansion of the LDPE matrix. The intensity of the PTC effect for these composites was found to be as large as nine orders of magnitude. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers.
In situ polymerization of polyamide 66 nanocomposites utilizing interfacial polycondensation. II. Sodium montmorillonite nanocomposites
Authors: Kalkan Zehra S. , Goettler Lloyd A. 
Published: June 2009

AbstractInterfacial polycondensation (IPC) is used to generate polyamide 66 (PA66) nanocomposite using sodium montmorillonite (NaMMT), which offers better thermal stability than organically modified montmorillonite. Several approaches are used to obtain different levels of dispersion for studying the factors affecting dispersion of NaMMT layered‐silicates. These approaches include dispersing NaMMT in either aqueous media or in a compatible nonaqueous medium. Moreover, clay slurry was added to the reaction media separately or in combination with the aqueous hexamethylenediamine solution, which includes either excess amine or sodium carbonate as the by‐product scavenger, in order to study the effect of sequencing on the dispersion of NaMMT. Several characterization techniques including dynamic mechanical analysis, wide angle X‐ray diffraction, and transmission electron microscopy are used to examine the structure and relate it to the mechanical properties of the nanocomposites. Results show that in situ polymerization techniques predominantly give rise to hybrid exfoliated–intercalated NaMMT structure. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Structure and properties of fluorinated polymer/poly(ethylene oxide) blends
Authors: Liu Tao , Ye Lin 
Published: June 2009

AbstractBACKGROUND: In order to explore ways for improving the toughness of copolymers of vinylidene difluoride and chlorotrifluoroethylene (P(VDF‐CTFE)), polyethylene oxide (PEO) with ultrahigh molecular weight and good mechanical properties was applied for the first time to prepare P(VDF‐CTFE)/PEO blends for adhesives applications.RESULTS: The results show that with an increase of PEO content, the mechanical properties of the blends are improved markedly, and blends with high strength, modulus and toughness are obtained. The difference in the solubility parameters of P(VDF‐CTFE) and PEO is small, and only a single α‐relaxation peak is observed in the high‐temperature zone for the blends, indicating that the blend system is partially miscible. The experimental values for the glass transition temperature of the blend varying with PEO content are always higher than those predicted by the Fox equation, and a strong interaction is supposed to occur between the molecules of P(VDF‐CTFE) and PEO. The relative crystallinity of the blends increases with PEO content, and the PEO particles disperse homogeneously in the P(VDF‐CTFE) matrix, whose average size decreases with increasing PEO content. Phase‐inverted morphologies of the blends are observed above 60 wt% of PEO.CONCLUSION: The partial miscibility of P(VDF‐CTFE)/PEO blends leads to an improvement of the mechanical properties of the blends, which is an effective way to improve the toughness of fluorinated polymers. Copyright © 2009 Society of Chemical Industry
Solution prepolymerization as a new route for preparing aliphatic polyurethane prepolymers using high‐throughput experimentation
Authors: Majoros László I. , Dekeyser Bernard , Hoogenboom Richard , Fijten Martin W. M. , Haucourt Nancy , Schubert Ulrich S. 
Published: June 2009

AbstractHigh‐throughput experimentation (HTE) represents a promising and versatile approach for polyurethane (PU) research as a tool to screen and characterize a large number of samples in an automated way. For the realization of a HTE workflow for PUs, the use of a Chemspeed Accelerator™ SLT106 automated parallel synthesizer was explored. To evaluate the possibility of these techniques for PUs, we studied the synthesis of prepolymers from isophorone diisocyanate and polypropylene glycol in mass and solution. Several optimization steps, transfer to solution polymerization, and downscaling prepolymerizations have been carried out in a manual way before implementing them into the Chemspeed Accelerator™. As a next step, reproducibility investigations and kinetic studies were performed in an automated manner. All experiments were evaluated by characterization with gel permeation chromatography, MALDI–TOF mass spectrometry and 1H NMR spectroscopy. These results provide a basis to use the HTE technique for screening different PU prepolymers in the future. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3729–3739, 2009
Investigation of the conformation of hyperbranched poly(arylene oxindole)s using hyper‐Rayleigh scattering
Authors: Vandendriessche Annelies , Asselberghs Inge , Clays Koen , Smet Mario , Dehaen Wim , Verbiest Thierry , Koeckelberghs Guy 
Published: June 2009

AbstractA hyperbranched poly(arylene oxindole), a poly(methacrylate), and a dendrimer, to which the same nonlinear optical chromophore was attached via a small, rigid spacer, were prepared. The difference in hyper‐Rayleigh scattering intensities was measured and compared. From this study, it was concluded that the chromophores, and hence the functional groups in the macromolecule before functionalization, are orientationally correlated in the dendrimer, whereas they are not in the linear and hyperbranched polymer. More in particular, the chromophores in the dendrimer are fixed in a centrosymmetric way because of the globular structure, whereas there is no orientational correlation between the chromophores in linear and hyperbranched polymer. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3740–3747, 2009
Synthesis of Boltorn 1,2,3‐triazole dendrimers by click chemistry
Authors: Katritzky Alan R. , Song Yuming , Sakhuja Rajeev , Gyanda Reena , Meher Nabin K. , Wang Ling , Duran Randolph S. , Ciaramitaro David A. , Bedford Clifford D. 
Published: June 2009

AbstractSecond‐, third‐, and fourth‐generation hyperbranched aliphatic polyols namely Boltorn® H20, Boltorn H30, and Boltorn H40 were endcapped with azido and activated acetylenic groups in good to excellent yields (75–95%) following an acid catalyzed procedure. The resultant terminally functionalized dendritic azido and acetylenic groups undergo 1,3‐dipolar cycloaddition using methyl (or ethyl) propiolate and benzyl azide, respectively, under catalytic or noncatalytic conditions below 40 °C to yield 1,2,3‐triazole dendrimeric polymers in 82–95% yield, under extremely mild conditions that could be applied for compounds sensitive to acid, base, or heat. The dendritic azido and activated acetylenic derivatives may act as novel scaffolds to tune the mechanical properties of different polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3748–3756, 2009
A versatile approach for the syntheses of poly(ester amide)s with pendant functional groups
Authors: Atkins Katelyn M. , Lopez David , Knight Darryl K. , Mequanint Kibret , Gillies Elizabeth R. 
Published: June 2009

AbstractPoly(ester amide)s (PEAs) are emerging as promising materials for a wide range of biomedical applications due to their potential for both hydrolytic and enzymatic degradation, as well as the ease with which their properties can be tuned by the choice of monomers. The incorporation of pendant functional handles along the PEA backbone has the potential to further expand their applications by allowing the charge and hydrophilicity of the polymers to be altered, and facilitating the conjugation of active molecules such as drugs, targeting groups, and cell signaling molecules. Described here is a simple and versatile strategy based on orthogonal protecting groups, by which L‐lysine and L‐aspartic acid can be incorporated into several families of PEAs based on monomers including the diacids succinic and terephthalic acid, the diols 1,4‐butanediol and 1,8‐octanediol, and the amino acids L‐alanine and L‐phenylalanine. All polymers were thoroughly characterized by nuclear magnetic resonance spectroscopy, infrared spectroscopy, size exclusion chromatography, thermogravimetric analysis, and differential scanning calorimetry. It was demonstrated that the side chain protecting groups could be readily removed, allowing the pendant amines or carboxylic acids to be functionalized. In particular, the carboxylic acid groups on a polymer containing L‐aspartic acid units were converted to N‐hydroxysuccinimidyl esters, providing a useful template for further derivatization. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3757–3772, 2009
Controlled/living heterogeneous radical polymerization in supercritical carbon dioxide
Authors: Zetterlund Per B. , Aldabbagh Fawaz , Okubo Masayoshi 
Published: June 2009

AbstractSupercritical carbon dioxide (scCO2) is an inexpensive and environmentally friendly medium for radical polymerizations. ScCO2 is suited for heterogeneous controlled/living radical polymerizations (CLRPs), since the monomer, initiator, and control reagents (nitroxide, etc.) are soluble, but the polymer formed is insoluble beyond a critical degree of polymerization (Jcrit). The precipitated polymer can continue growing in (only) the particle phase giving living polymer of controlled well‐defined microstructure. The addition of a colloidal stabilizer gives a dispersion polymerization with well‐defined colloidal particles being formed. In recent years, nitroxide‐mediated polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible addition fragmentation chain transfer (RAFT) polymerization have all been conducted as heterogeneous polymerizations in scCO2. This Highlight reviews this recent body of work, and describes the unique characteristics of scCO2 that allows composite particle formation of unique morphology to be achieved. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3711–3728, 2009
Birth weight and lung function in a cohort of Chinese school children
Authors: Qi‐qiang He , Tze‐wai Wong , Lin Du , Zhuo‐qin Jiang , Yang Gao , Guo‐zhen Lin , Ignatius Yu Tak‐sun 
Published: June 2009

AbstractObjectiveEvidence on the association between birth weight and lung function is conflicting. We evaluated the children's lung function in relation to their birth weight in China.MethodsA prospective cohort study was conducted in 1,599 school children. Baseline data on birth weight and other potential confounding variables were obtained from self‐administered questionnaires. Pulmonary function tests were performed with a standard procedure and repeated 6 months later.ResultsThere were no significant differences in the standard deviation score (SDS) of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) between children with low birth weight (LBW) and those with normal birth weight (NBW). The growth rates in lung function between children with LBW and NBW were also insignificant.ConclusionsNo association between birth weight and lung function was found among Chinese school children. Pediatr Pulmonol. 2009; 44:662–668. © 2009 Wiley‐Liss, Inc.
Tropical cyclone spin‐up revisited
Authors: Smith Roger K. , Montgomery Michael T. , Van Sang Nguyen 
Published: June 2009

AbstractWe present numerical experiments to investigate axisymmetric interpretations of tropical cyclone spin‐up in a three‐dimensional model. Two mechanisms are identified for the spin‐up of the mean tangential circulation. The first involves the convergence of absolute angular momentum above the boundary layer and is a mechanism to spin up the outer circulation, i.e. to increase the vortex size. The second involves the convergence of absolute angular momentum within the boundary layer and is a mechanism to spin up the inner core. It is associated with the development of supergradient wind speeds in the boundary layer. The existence of these two mechanisms provides a plausible physical explanation for certain long‐standing observations of typhoons by Weatherford and Gray, which indicate that inner‐core changes in the azimuthal‐mean tangential wind speed often occur independently from those in the outer core. The unbalanced dynamics in the inner‐core region are important in determining the maximum radial and tangential flow speeds that can be attained, and therefore important in determining the azimuthal‐mean intensity of the vortex. We illustrate the importance of unbalanced flow in the boundary layer with a simple thought experiment. The analyses and interpretations presented are novel and support a recent hypothesis of the boundary layer in the inner‐core region. Copyright © 2009 Royal Meteorological Society
A contribution by ice nuclei to global warming
Authors: Zeng Xiping , Tao Wei‐Kuo , Zhang Minghua , Hou Arthur Y. , Xie Shaocheng , Lang Stephen , Li Xiaowen , Starr David O'C , Li Xiaofan 
Published: June 2009

AbstractIce nuclei (IN) significantly affect clouds via supercooled droplets, that in turn modulate atmospheric radiation and thus climate change. Since the IN effect is relatively strong in stratiform clouds but weak in convective ones, the overall effect depends on the ratio of stratiform to convective cloud amount. In this paper, ten years of TRMM (Tropical Rainfall Measuring Mission) satellite data are analyzed to confirm that stratiform precipitation fraction increases with increasing latitude, which implies that the IN effect is stronger at higher latitudes.To quantitatively evaluate the IN effect versus latitude, large‐scale forcing data from ten field campaigns are used to drive a cloud‐resolving model to generate long‐term cloud simulations. As revealed in the simulations, the increase in the net downward radiative flux at the top of the atmosphere from doubling the current IN concentrations is larger at higher latitude, which is attributed to the meridional tendency in the stratiform precipitation fraction.Surface warming from doubling the IN concentrations, based on the radiative balance of the globe, is compared with that from anthropogenic CO2. It is found that the former effect is stronger than the latter in middle and high latitudes but not in the Tropics.With regard to the impact of IN on global warming, there are two factors to consider: the radiative effect from increasing the IN concentration and the increase in IN concentration itself. The former relies on cloud ensembles and thus varies mainly with latitude. In contrast, the latter relies on IN sources (e.g. the land surface distribution) and thus varies not only with latitude but also longitude. Global desertification and industrialization provide clues on the geographic variation of the increase in IN concentration since pre‐industrial times. Thus, their effect on global warming can be inferred and can then be compared with observations. A general match in geographic and seasonal variations between the inferred and observed warming suggests that IN may have contributed positively to global warming over the past decades, especially in middle and high latitudes. Copyright © 2009 Royal Meteorological Society