bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intermolecular interaction in aqueous solution of binary blends of poly(acrylamide) and poly(ethylene glycol)
Authors: Lü Ting , Shan Guorong , Shang Songmin 
Published: June 2010

AbstractThe interaction between poly(acrylamide) (PAM) and poly(ethylene glycol) (PEG) in their solid mixture was studied by Fourier transform infrared spectroscopy (FTIR); and their interaction in aqueous solution was investigated by nuclear magnetic resonance spectroscopy (NMR). For the solid PAM/PEG mixtures, an induced shift of the >CO and >NH in amide group was found by FTIR. These results could demonstrate the formation of intermolecular hydrogen bonding between the amide group of PAM and the ether group of PEG. In the aqueous PAM/PEG solution system, the PAM and PEG associating with each other in water, i.e., the amide group of PAM interacting with the ether group of PEG through hydrogen bonding was also found by 1H NMR. Furthermore, the effects of different molecular weight of PAM on the strength of hydrogen bonding between PAM and PEG in water were investigated systemically. It was found that the hydrogen bonding interaction between PAM and PEG in water did not increase with the enlargement of the PAM molecular weight as expected. This finding together with the viscosity reduction of aqueous PAM/PEG solution with the PAM molecular weight increasing strongly indicated that PAM molecular chain, especially having high molecular weights preferred to form spherical clews in aqueous PEG solution. Therefore, fewer amide groups in PAM could interact with the ether groups in PEG. Based on these results, a mechanism sketch of the interaction between PAM and PEG in relatively concentrated aqueous solution was proposed. The fact that the phase separation of aqueous PAM/PEG solution occurs while raising the temperature indicates that this kind of hydrogen bonding between PAM and PEG in water is weak and could be broken by controlling the temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of an organic soluble and conducting polyaniline‐grafted multiwalled carbon nanotube core–shell nanocomposites by emulsion polymerization
Authors: Xu Jun , Yao Pei , Liu Litao , Jiang Zhongyi , He Fei , Li Mei , Zou Jingyu 
Published: June 2010

AbstractOrganic soluble and conducting polyaniline (PANI)‐grafted multiwalled carbon nanotube (MWNT) nanocomposites were synthesized by in situ emulsion polymerization. Dodecyl benzene sulfonic acid (DBSA) acted as both a dopant and emulsifier, and phenylamine groups grafted on the surface of the MWNTs via amide bonding joined in the in situ polymerization. As self‐assembly templates, multiwalled carbon nanotubes containing phenylamine groups (p‐MWNTs) were encapsulated by PANI to form a homogeneous core (p‐MWNTs)–shell (DBSA‐doped PANI) nanostructure. The attachment of soluble DBSA‐doped PANI chains on the surface of the p‐MWNTs via covalent bonding rendered the p‐MWNTs compatible with the polymer matrix and led to the nanocomposite being highly soluble and stable in tetrahydrofuran. The PANI chains grew restrictively on the surface of the p‐MWNTs, and the crystalline orders of the PANI coatings were enhanced. Because of the incorporation of the p‐MWNTs, the thermal stability of the nanocomposites was improved, and the conductivity of the nanocomposites at room temperature was increased by at least one order of magnitude over neat DBSA‐doped PANI. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of star‐shaped poly(ε‐caprolactone)‐b‐poly(L‐lactide) copolymers: From star architectures to crystalline morphologies
Authors: Ren Jie , Zhang Zhonghai , Feng Yue , Li Jianbo , Yuan Weizhong 
Published: June 2010

AbstractHexa‐armed star‐shaped poly(ε‐caprolactone)‐block‐poly(L‐lactide) (6sPCL‐b‐PLLA) with dipentaerythritol core were synthesized by a two‐step ring‐opening polymerization. GPC and 1H NMR data demonstrate that the polymerization courses are under control. The molecular weight of 6sPCLs and 6sPCL‐b‐PLLAs increases with increasing molar ratio of monomer to initiator, and the molecular weight distribution is in the range of 1.03–1.10. The investigation of the melting and crystallization demonstrated that the values of crystallization temperature (Tc), melting temperature (Tm), and the degree of crystallinity (Xc) of PLLA blocks are increased with the chain length increase of PLLA in the 6sPCL‐b‐PLLA copolymers. On the contrary, the crystallization of PCL blocks dominates when the chain length of PLLA is too short. According to the results of polarized optical micrographs, both the spherulitic growth rate (G) and the spherulitic morphology are affected by the macromolecular architecture and the length of the block chains. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of azobenzene units on imidization kinetic of novel poly(ester amic acid)s and polymers properties before and after cyclodehydration
Authors: Schab‐Balcerzak Ewa , Janeczek Henryk , Kucharski Piotr 
Published: June 2010

AbstractIn this article, the imidization reaction kinetic of novel poly(ester amic acid)s with azobenzene units as side groups was studied by dynamic experiments by means of differential scanning calorimetry. Polymers differ in the number of chromophore moieties in their repeating unit and position in which azobenzene group is attached to the polymer chain. The kinetic parameters of poly(ester amic acid)s conversion to poly(ester imide)s was compared with data calculated for parent polymer, that is, without azobenzene groups. For the first time to our knowledge, the imidization kinetic of polymers with side azobenzene groups was studied. Kinetic parameters, such as the activation energy and frequency factor were estimated with the by Ozawa model [(E(O) and A(O)), respectively] and Kissinger model [(E(K) and A(K), respectively]. The values of activation energy determined with both models were in the range 167.1–198.3 kJ/mol. The lowest activation energy of imidization reaction exhibited polymer in which azobenzene units were placed between amide linkages. Polymers were characterized by FTIR, 1H‐NMR, X‐ray, and UV–vis methods. The glass transition temperature of resultant poly(ester imide)s was in the range of 217–237°C. The presence of chromophore units slightly decreased Tg and significantly improved their solubility and optical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Experimental investigation of the governing parameters in the electrospinning of poly(3‐hydroxybutyrate) scaffolds: Structural characteristics of the pores
Authors: Tehrani Ashkan Heidarkhan , Zadhoush Ali , Karbasi Saeed , Khorasani Saied Nouri 
Published: June 2010

AbstractWe sought to determine the impact of electrospinning parameters on a trustworthy criterion that could evidently improve the maximum applicability of fibrous scaffolds for tissue regeneration. We used an image analysis technique to elucidate the web permeability index (WPI) by modeling the formation of electrospun scaffolds. Poly(3‐hydroxybutyrate) (P3HB) scaffolds were fabricated according to predetermined conditions of levels in a Taguchi orthogonal design. The material parameters were the polymer concentration, conductivity, and volatility of the solution. The processing parameters were the applied voltage and nozzle‐to‐collector distance. With a law to monitor the WPI values when the polymer concentration or the applied voltage was increased, the pore interconnectivity was decreased. The quality of the jet instability altered the pore numbers, areas, and other structural characteristics, all of which determined the scaffold porosity and aperture interconnectivity. An initial drastic increase was observed in the WPI values because of the chain entanglement phenomenon above a 6 wt % P3HB content. Although the solution mixture significantly (p < 0.05) changed the scaffold architectural characteristics as a function of the solution viscosity and surface tension, it had a minor impact on the WPI values. The solution mixture gained the third place of significance, and the distance was approved as the least important factor. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Oxidized multiwalled carbon nanotubes as effective reinforcement and thermal stability agents of poly(lactic acid) ligaments
Authors: Chrissafis K. , Paraskevopoulos K. M. , Jannakoudakis A. , Beslikas T. , Bikiaris D. 
Published: June 2010

AbstractIn this study, nanocomposites of poly(lactic acid) (PLA) containing 0.5, 1, and 2.5 wt % oxidized multiwalled carbon nanotubes (MWCNT–COOHs) were prepared by the solved evaporation method. From transmission electron microscopy and scanning electron microscopy micrographs, we observed that the MWCNT–COOHs were well dispersed in the PLA matrix and, additionally, there was increased adhesion between PLA and the nanotubes. As a result, all of the studied nanocomposites exhibited higher mechanical properties than neat PLA; this indicated that the MWCNT–COOHs acted as efficient reinforcing agents, whereas in the nonoxidized multiwalled carbon nanotubes, the mechanical properties were reduced. Nanotubes can act as nucleating agents and, thereby, affect the thermal properties of PLA and, especially, the crystallization rate, which is faster than that of neat PLA. From the thermogravimetric data, we observed that the PLA/MWCNT–COOH nanocomposites presented relatively better thermostability than PLA; this was also verified from the calculation of activation energy. On the contrary, the addition of MWCNT–COOH had a negative effect on the enzymatic hydrolysis rate of PLA. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of boron‐containing materials on the flammability and thermal degradation of polyamide 6 composites containing melamine
Authors: Doğan Mehmet , Bayramlı Erdal 
Published: June 2010

AbstractThree different boron‐containing substances—zinc borate (ZnB), borophosphate (BPO4), and a boron‐ and silicon‐containing oligomer (BSi)—were used to improve the flame retardancy of melamine in a polyamide 6 (PA‐6) matrix. The combustion and thermal degradation characteristics of PA‐6 composites were investigated with the limiting oxygen index (LOI), the UL‐94 standard, thermogravimetric analysis (TGA)/Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). A slight increase was seen in the LOI values of a sample containing BSi (1 wt %). BPO4 at high loadings showed a V0 rating (indicating the best flame retardancy) and slightly lower LOI values in comparison with samples with only melamine. For ZnB and BSi, glassy film and char formation decreased the dripping rate and sublimation of melamine, and this led to low LOIs. According to the TGA–FTIR results, the addition of boron compounds did not change the decomposition product distribution of melamine and PA‐6. The addition of boron compounds affected the flame retardancy by physical means. The TGA data showed that boron compounds and melamine reduced the decomposition temperature of PA‐6. According to the DSC data, the inclusion of boron compounds increased the onset temperature of sublimation of melamine and also affected the flame retardancy negatively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Pigment dyeing of polyamide‐epichlorohydrin cationized cotton fabrics
Authors: Fang Kuanjun , Zhang Lianbing , Xu Yi , Zhang Xia 
Published: June 2010

AbstractA synthesized cationic reagent named polyamide‐epichlorohydrin (PAE) was used to cationize cotton fabrics which were dyed with nanoscale pigments after PAE modification. The results showed that when the PAE concentration was below 7% (owf), the K/S value increased nearly linearly with increasing of PAE concentration, and excess that concentration the K/S value did not increase further. With increasing the pH value of cationization bath, the K/S value increased first and then decreased, the maximum K/S value appeared at pH 9–10. Cotton fabrics cationized at 80°C for 20 min exhibited the best cationizing result. Both the pigment uptake and the color strength reached their own maximum values when the dye bath was neutral. When the pigment concentration was 1% (owf) the addition of 1g/L sodium chloride in the dye bath could decrease the pigment uptake while for 5% (owf) pigment concentration the uptake increased with increasing the amount of sodium chloride. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Improvement in voltage, thermal, mechanical stability and ion transport properties in polymer‐clay nanocomposites
Authors: Sharma A. L. , Thakur Awalendra K. 
Published: June 2010

AbstractWe report novel results on optimization of intercalated polymer‐clay nanocomposite endowed with desirable properties like, (i) very high ionic conductivity (∼ 10−3 S cm−1) at room temperature, (ii) substantial improvement in voltage stability (∼ 5.6 V), mechanical stability (25 MPa), and thermal stability (250°C) (iii) tion ∼ 99% and cation transport number (tLi+) ∼ 67%: Intercalation of polymer salt (PAN)8LiCF3SO3 complex into dodecylamine modified montmorillonite clay (DMMT) nanometric channels has been confirmed by X‐ray diffraction and Transmission electron microscopy analysis. Complex impedance spectroscopy suggests bulk electrical conduction in the high frequency region and electrode polarization effect at the low frequencies. The experimental value of conductivity, voltage, and mechanical stability is observed to be invariably higher in polymer nanocomposite film when compared with clay free polymer‐salt complex film. The same is true for cation transport. The optimized polymer film serves dual purpose of electrolyte and separator in energy storage devices. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Study on the properties of magnetorheological gel based on polyurethane
Authors: Wei Bing , Gong Xinglong , Jiang Wanquan , Qin Lijun , Fan Yanceng 
Published: June 2010

AbstractMagnetorheological gels (MRGs) known as a new kind of magnetorheological material are composite gels containing magnetic particles suspended in polymer gels. In this study, a category of MR polymer gels based on polyurethane (PU) were prepared. The microstructures of these MRGs were observed with a digital microscope. Their rheological properties under both steady shear and oscillation testing were characterized by using a MR rheometer. The viscosity of the PU MRG decreased with the increment of NCO/OH ratio and increased with the increment of the weight concentration of carbonyl iron particles, molecular mass of poly propylene glycol, and applied magnetic field. The storage modulus increased gradually with the increment of applied magnetic field and weight concentration of carbonyl iron particles. The PU MRG exhibits high static shear yield stress (60.8 kPa, at 573 mT) and dynamic shear yield stress (83.9 kPa, at 573 mT) and wide variation range (static shear yield stress: 6–62 kPa, dynamic shear yield stress: 15–85 kPa). These advantages indicate that PU MRG is able to satisfy wide applications. In addition, both static and dynamic shear yield stresses of the MRG samples increase with the increment of molar mass of polypropylene glycol. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The demography of introduction pathways, propagule pressure and occurrences of non‐native freshwater fish in England
Authors: Copp G. H. , Vilizzi L. , Gozlan R. E. 
Published: June 2010

Abstract
Biological invasion theory predicts that the introduction and establishment of non‐native species is positively correlated with propagule pressure. Releases of pet and aquarium fishes to inland waters has a long history; however, few studies have examined the demographic basis of their importation and incidence in the wild.
For the 1500 grid squares (10×10 km) that make up England, data on human demographics (population density, numbers of pet shops, garden centres and fish farms), the numbers of non‐native freshwater fishes (from consented licences) imported in those grid squares (i.e. propagule pressure), and the reported incidences (in a national database) of non‐native fishes in the wild were used to examine spatial relationships between the occurrence of non‐native fishes and the demographic factors associated with propagule pressure, as well as to test whether the demographic factors are statistically reliable predictors of the incidence of non‐native fishes, and as such surrogate estimators of propagule pressure.
Principal coordinates of neighbour matrices analyses, used to generate spatially explicit models, and confirmatory factor analysis revealed that spatial distributions of non‐native species in England were significantly related to human population density, garden centre density and fish farm density. Human population density and the number of fish imports were identified as the best predictors of propagule pressure.
Human population density is an effective surrogate estimator of non‐native fish propagule pressure and can be used to predict likely areas of non‐native fish introductions. In conjunction with fish movements, where available, human population densities can be used to support biological invasion monitoring programmes across Europe (and perhaps globally) and to inform management decisions as regards the prioritization of areas for the control of non‐native fish introductions.
© Crown copyright 2010. Reproduced with the permission of her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Detecting North American signal crayfish (Pacifastacus leniusculus) in riffles
Authors: Gladman Z. F. , Yeomans W. E. , Adams C. E. , Bean C. W. , McColl D. , Olszewska J. P. , McGillivray C. W. , McCluskey R. 
Published: June 2010

Abstract
The spread of the invasive signal crayfish (Pacifastacus leniusculus) outside its natural range is of widespread concern due to the threats posed to native biodiversity. To date, there is no standard protocol for determining signal crayfish presence or absence in a watercourse.
For the purposes of this investigation, the crayfish detection ability of active sampling methods — hand‐netting, electrofishing (one, two and three runs), kick sampling and Surber sampling — was tested at 30 sites along the River Clyde, southern central Scotland.
No single technique was successful in detecting crayfish in 100% of the sites known to contain crayfish and so the application of combinations of techniques was considered. The combination of techniques that resulted in a 100% detection rate was electrofishing (three runs) together with kick sampling. These results suggest that three‐run electrofishing and kick sampling are the best candidates for incorporation into a crayfish detection protocol.
The mean time taken to apply electrofishing (three runs) was significantly greater than the mean time to apply kick sampling. Given the lower effort required for its application, kick sampling is recommended as the preliminary technique: if kick sampling yields a negative result, the application of electrofishing will decrease the chance of recording a false negative presence. If both kick sampling and electrofishing fail to detect crayfish, trapping may further decrease the risk of a false negative result.
These findings have assisted in the development of a crayfish detection protocol, which will be applied across Scotland to determine the current distribution of signal crayfish. Copyright © 2010 John Wiley & Sons, Ltd.
Inhibitors of p38 suppress cytokine production in rheumatoid arthritis synovial membranes: Does variable inhibition of interleukin‐6 production limit effectiveness in vivo?
Authors: Page Theresa H. , Brown Anthony , Timms Emma M. , Foxwell Brian M. J. , Ray Keith P. 
Published: June 2010

AbstractObjectiveThe activity of p38 MAPK regulates lipopolysaccharide (LPS)–stimulated production of key proinflammatory cytokines such as tumor necrosis factor α (TNFα). Consequently, p38 MAPK inhibitors have attracted considerable interest as potential treatments of rheumatoid arthritis (RA), and studies in murine models of arthritis have yielded promising results. However, the performance of several compounds in human clinical trials has been disappointing. At present, the reason for this poor performance is unclear. The aim of this study was to examine the effects of p38 inhibitors on both diseased and normal human tissue and cells, in order to test whether this kinase still plays a critical role in cytokine production under conditions of chronic inflammation.MethodsProinflammatory and antiinflammatory cytokine production was monitored after treatment of primary human monocytes, macrophages, and RA synovial membrane cultures with p38 MAPK inhibitor compounds. The following 3 inhibitors were used in these studies: SB‐203580 (inhibits the α and β isoforms), BIRB‐796 (inhibits the α, β, γ, and δ isoforms), and a novel, structurally distinct p38 MAPK inhibitor, SB‐731445 (inhibits the α and β isoforms).ResultsSB‐731445 and SB‐203580 produced profound inhibition of spontaneous production of proinflammatory cytokines (TNFα and interleukin‐1 [IL‐1]) in both RA membrane cultures and LPS‐stimulated primary human monocytes. However, this and other p38 MAPK inhibitors produced a significant increase in IL‐6 production by LPS‐stimulated primary human macrophages and a decrease in IL‐10 production by all cell types examined.ConclusionThe potentially proinflammatory consequences of these activities (decreased IL‐10 production and increased IL‐6 production) may offer some explanation for the inability of p38 MAPK inhibitors to provide the therapeutic benefit that had been hoped for in RA.
MicroRNA‐125a contributes to elevated inflammatory chemokine RANTES levels via targeting KLF13 in systemic lupus erythematosus
Authors: Zhao Xia , Tang Yuanjia , Qu Bo , Cui Huijuan , Wang Shujun , Wang Lijia , Luo Xiaobing , Huang Xinfang , Li Jia , Chen Shunle , Shen Nan 
Published: June 2010

AbstractObjectiveMicroRNA (miRNA) have received increasing attention as posttranscriptional regulators that fine‐tune the homeostasis of the inflammatory response. This study aimed to clarify whether miR‐125a, which was identified in a pilot expression profiling step, is involved in the inflammatory chemokine pathway in systemic lupus erythematosus (SLE).MethodsIndependent verification of miR‐125a expression in amplified samples from SLE patients and normal controls was performed by TaqMan quantitative polymerase chain reaction (PCR) analysis. A combination of 3 bioinformatic prediction techniques and reporter gene assays was used to identify miR‐125a targets. In vitro systems of overexpression by transfection and inducible expression by stimulation were performed to investigate the function of miR‐125a, which was followed by real‐time quantitative PCR and enzyme‐linked immunosorbent assay.ResultsIn SLE patients, the expression of miR‐125a was reduced and the expression of its predicted target gene, KLF13, was increased. Bioinformatics predicted that miR‐125a base‐paired with sequences in the 3′‐untranslated region of KLF13. Overexpression of miR‐125a led to a significant reduction in the expression of RANTES and KLF13. MicroRNA‐125a inhibited endogenous KLF13 expression in a dose‐dependent manner, as determined using gain‐ and loss‐of‐function methods. A luciferase reporter system confirmed the miR‐125a binding sites. Notably, miR‐125a expression was induced in T cells in a dose‐ and time‐dependent manner. Finally, the introduction of miR‐125a into T cells from SLE patients alleviated the elevated RANTES expression.ConclusionMicroRNA‐125a negatively regulates RANTES expression by targeting KLF13 in activated T cells. The underexpression of miR‐125a contributes to the elevated expression of RANTES in SLE. Our findings extend the role of miRNA in the pathogenesis of lupus and provide potential strategies for therapeutic intervention.