bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonisothermal crystallization behavior of Cu/LDPE nanocomposites prepared by solution blending method
Authors: Peng Zhongrui , Cai Shuizhou , Xia Xianping , Xie Changsheng 
Published: November 2011

AbstractThe nonisothermal crystallization behavior of Copper/low‐density polyethylene (LDPE) nanocomposites was investigated by differential scanning calorimetry (DSC). The nanocomposites were prepared by solution blending method, and the traditional extrusion melt method was also employed for comparison. The DSC results show that under identical copper content condition, the crystallization of the LDPE is facilitated owing to the higher degree of molecular regularity and the lesser chain entanglement for the nanocomposites prepared by the solution blending method in comparison with the traditional extrusion melt method. The differences of nonisothermal crystallization behavior diminish with the increasement of copper content between the nanocomposites prepared by the two methods. SEM/EDX was applied to study the dispersion of copper nanoparticles in the nanocomposites, and the results illustrate that the dispersion condition can be better when the solution blending method was employed. The investigation of the effective activation energy on the relative extent crystallization implies that the agglomeration of copper nanoparticles can facilitate the crystallization of the LDPE, while the well‐dispersed copper nanoparticles act as obstacles since the motion of the LDPE molecular chains is limited. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of plasma pretreatment on enhancing wrinkle resistant property of cotton fiber treated with BTCA and TiO2 System
Authors: Lam Y. L. , Kan C. W. , Yuen C. W. M. 
Published: November 2011

Abstract1,2,3,4‐butanetetracarboxylic acid (BTCA) with titanium dioxide as a catalyst, was used to crosslink cotton fibers for the purpose of enhancing wrinkle recovery angle (WRA). To enhance the BTCA treatment with TiO2, surface modification of cotton fiber is required; atmospheric pressure plasma jet pretreatment was used in experiments reported in this article. In this study, optimum conditions for plasma pretreatment were analyzed using orthogonal array testing strategy (OATS) technique, on the basis of WRAs achieved after BTCA treatment with and without TiO2 as catalyst. It was found that (i) longer duration of plasma pretreatment provides enough time for the substrate to be impacted by the concentrated active species produced in plasma gas and therefore, modifies the material surface effectively and offers the best balance between enhancement of WRA and minimization of fiber damage, (ii) high oxygen flow rate producing a severe etching effect that alters the material's surface characteristics. However, when concentration of O2 increased during the plasma pretreatment, the active species might react with the oxygen also, besides the cotton surface, and (iii) when the distance between the plasma jet nozzle and the substrate surface is too large, plasma gas from the nozzle is unable to hit the fabric surface, which means no surface modification is achieved. As a result, plasma treatment with 2 mm/s treatment speed, 0.1 L/min oxygen flow rate, and 2 mm jet‐to‐substrate distance was the most effective plasma pretreatment. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Compatibilizing efficiency of copolymer precursors for immiscible polymer blends
Authors: Yu Qi‐Yong , Zhang Cai‐Liang , Gu Xue‐Ping , Wang Jia‐Jun , Feng Lian‐Fang 
Published: November 2011

AbstractAn anhydride‐terminated polystyrene (PS‐b‐Anh) as a block copolymer precursor and a copolymer (PS‐co‐TMI) of styrene (St) and 3‐isopropenyl‐α,α‐dimethylbenzene isocyanate (TMI) as a graft copolymer precursor are chosen to investigate the effect of the type of the copolymer precursor on its compatibilizing and stabilizing efficiency for polymer blends. Results show that during the melt blending of the PS and PA6, the addition of PS‐b‐Anh dramatically decreases the size of the dispersed phase domains, irrespective of its molecular weight. This indicates that a diblock copolymer PS‐block‐PA6 (PS‐b‐PA6) is formed by a reaction between the terminal anhydride moiety of the PS‐b‐Anh and the terminal amine group of the PA6. When PS/PA6 (30/70) blends are annealed at 230°C for 15 min, their morphologies are much more stable in the presence of the PS‐b‐Anh block copolymer precursor than in the presence of the PS‐co‐TMI graft copolymer precursor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A convenient route to modified multiwall carbon nanotubes with liquid crystal molecules via covalent functionalization
Authors: Chen Xianhong , Wu Xiaoli , Zou Jiagui , Wan Jianping 
Published: November 2011

AbstractA novel nanocomposite of the rod‐like liquid crystal (LC) molecules' waist positions anchored on the surface (sidewalls and ends) of multiwall carbon nanotubes (MWNTs) was prepared by using a dissolving metal reduction method for the first time. The MWNTs carbanion complexes of lithium were first synthesized in tetrahydrofuran with an electron transfer from lithium naphthalene radical anion on the surface of MWNTs. Then the novel material (LC‐MWNTs) was obtained by treating the carbanion complexes with bromic liquid crystalline aromatic amide compound. The formation of the LC‐MWNTs was confirmed by both Raman and FTIR spectroscopies. HRTEM demonstrates that the rod‐like LC molecules are anchored on the surface of MWNTs via covalent attachment, with a wrapped thickness approximately 3‐4 nm. The loss‐weight fraction of the LC layers for the LC‐MWNTs can be roughly estimated as 23% by TGA. The experiments of solubility exhibit that the LC‐MWNTs forms a stable suspension solution in polar solvents such as dimethylformamide. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Charge transport mechanism in intercalated polypyrrole aluminum‐pillared montmorillonite clay nanocomposites
Authors: Shakoor Abdul , Rizvi Tasneem Zahra , Hina Maryam 
Published: November 2011

AbstractNanocomposites based on intercalated conducting polypyrrole (PPy) into the galleries of inorganic aluminum‐pillared Montmorillonite (Al‐PMMT) clay with varying concentrations of Al‐PMMT were prepared by in situ chemical polymerization. The intercalation was confirmed by X‐ray diffraction pattern. Charge transport mechanism in these composites was investigated by temperature dependent direct current conductivity measurements. An increase in DC conductivity value on addition of (Al‐PMMT) clay in the composites at all temperatures and a transition from three‐dimensional (3D) Mott's variable range hopping (VRH) process in pristine PPy to one‐dimensional (1D) Mott's VRH process in the intercalated polymer composites has been observed. This transition in charge transport mechanism of PPy from 3D VRH to 1D VRH on intercalation has been interpreted in terms of straightening and linearization of polymer chains and decrease in inter‐chain interactions in the intercalated PPy. Enhancement in mechanical properties and increase in thermal stability of the nanocomposites was also observed with the increase in weight percentage of Al‐PMMT in PPy‐Al‐PMMT composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Optimization of the chain transfer agent incremental addition in SBR emulsion polymerization
Authors: Delfa Gerardo Martínez , Boschetti Carlos E. 
Published: November 2011

AbstractThe incremental addition of chain transfer agent (CTA) in an emulsion styrene‐butadiene polymerization reaction was optimized, using a chemometric approach that involves (a) an experimental design, in which the amount of CTA in each addition were the factors; (b) an artificial neural network modeling to obtain responses for each required processability property (i.e., Mooney viscosity and number‐ and weight‐average molecular weight); and (c) a simultaneous desirability response, due to several properties had to be optimized at a time. As a result, an 8% increase in productivity was accomplished, and some relationships were derived among CTA additions and polymer evolution, Mooney viscosity and molecular weights. The study was carried out to further apply this strategy in the production plant. The challenge was to keep the quality of the produced polymer, particularly in terms of processability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
NIR‐laser based detection of the photopolymerization state of acrylate coatings suitable for in situ measurements
Authors: Bach M. , Heering W. 
Published: November 2011

AbstractThe present article describes a method for the determination of the radical photopolymerization conversion of acrylic coatings suitable for an in situ monitoring during the coating process. Acrylate based coatings are increasingly used in many kinds of industrial coating processes, because of advantages of the solvent‐free application process. The applied method is based on 1620 nm light absorption of the acrylate. To overcome the disadvantages of a common NIR spectrometer, only the diffuse reflection of the relevant discrete wavelength at 1620 nm and of a reference wavelength is measured. A sophisticated sensor setup including an optical spatial filter and lock‐in amplified signal processing is used to achieve a sufficient signal to noise ratio. The capability of the sensor to discriminate between polymerized and unpolymerized coatings on metal substrates down to a coating thickness of 16 μm is demonstrated. Furthermore, the information on polymerization from larger depth in TiO2 pigmented coatings is investigated. The results can be analytically modeled in analogy to the Lambert–Beer's law, resulting in a detection limit of a maximum pigment concentration of 15 wt % with 100 μm coating thickness. The presented sensor design is suitable to be used in an industrial production environment for example in screen printing applications as a monitoring and quality control tool. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Rhodium(I) complex catalyst immobilized on terpolymers of N‐vinylpyrrolidinone and 1‐vinylimidazole
Authors: Strzelec Krzysztof , Wąsikowska Karolina , Cypryk Marek , Pospiech Piotr 
Published: November 2011

AbstractThe hydrosilylation of cyclohexanone and acetone with triethysilane and diphenysilane catalyzed by polymer‐supported Rh(I) complex has been investigated. Two terpolymers of styrene, divinylbenzene, and 1‐vinylimidazole (S/DVB/VI) or N‐vinylpyrrolidinone (S/DVB/NVP) were used as the catalysts supports. Physical characterization of these materials has involved the measurements of the structural parameters in the dry and swollen states by DSC, the nitrogen BET adsorption method and inverse steric exclusion chromatography ISEC. From these results it can be concluded that the original polymer structure has been changed during the complex attachment giving rise to materials of higher porosity. X‐ray photoelectron spectroscopy XPS, IR, and AAS spectroscopy were used to characterization of heterogeneous complexes before and after use. The effect of the morphology of the support on the catalytic properties of the polymer‐supported Rh(I) species was tested in the hydrosilylation of ketones and correlated with the reaction mechanism. It was demonstrated that the high selectivity of homogeneous rhodium complex toward the silyl ethers can be partially reversed to the dehydrogenative silylation products by a proper choice of polymer support with favorable microporous structure. Recycling tests demonstrated high stability of the supported catalysts during prolonged use. The constant selectivity of the supported catalysts demonstrated during recycling experiments showed that they could be useful for practical application. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Production and characterization of poly(vinyl alcohol)/poly(vinylpyrrolidone) iodine/poly(ethylene glycol) electrospun fibers with (hydroxypropyl)methyl cellulose and aloe vera as promising material for wound dressing
Authors: Uslu İbrahim , Aytimur Arda 
Published: November 2011

AbstractBiocompatible poly(vinyl alcohol)/poly (vinylpyrrolidone) iodine/poly(ethylene glycol) fibers containing (hydroxypropyl)methyl cellulose (HPMC) and aloe vera were successfully prepared by electrospinning their aqueous solution. Aloe vera which is known to be effective in the treatment of various wounds was added to the polymer solution. HPMC was added to the system as the water retention agent. The hybrid fiber mats were subjected to detailed analysis using a differential scanning calorimeter, a scanning electron microscope (SEM), and a Fourier transform infrared spectrometer. Images obtained from the SEM showed that the polymer fibers were linear, homogenous, and contained no beading. The fiber diameters ranged between 100 and 900 nm. It was seen that the electrospun mats obtained could potentially be used as a material for dressing wounds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Secretion and formation of perimicrovillar membrane in the digestive system of the Sunn pest, Eurygaster integriceps (Hemiptera: Scutelleridae) in response to feeding
Authors: Mehrabadi Mohammad , Bandani Ali Reza 
Published: November 2011

AbstractIn this study, development of perimicrovillar membrane (PMM) from midgut cells of starved and fed Eurygaster integriceps (Hemiptera: Scutelleridae) was studied. Three different approaches, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), marker enzymes of the PMMs (α‐glucosidase), perimicrovillar space (aminopeptidase), and microvillar membranes (β‐glucosidase) were used. Activities of these enzymes were remarkably low in the starved insects. Moreover, microscopic observations revealed that PMM is not present in the starved insect. Activities of enzymatic markers increased at 5 h postfeeding, and TEM and SEM observations showed the formation of PMM as well as migration of double‐membrane vesicles from center of the columnar cell to the cell apex. The highest PMM was observed at 20 h postfeeding which at this time marker enzyme activity, such as α‐glucosidase activity, was high, too. Thus, at 20 h postfeeding, PMM system was evident and epithelial cells were completely covered by PMM system. After 20 h postfeeding, presence of the fine holes in PMM started to be seen and at 40 h post‐feeding, observation showed degradation of PMM system. Thus, it could be concluded that PMM in E. integriceps is secreted by epithelial cell membrane when needed and its secretion and formation is regulated by feeding. This system was not present in the starved insects as its development takes place at 5 h postfeeding. © 2011 Wiley Periodicals, Inc.
A Simplified Optimization Strategy for Nonlinear Tuned Mass Damper in Structural Vibration Control
Authors: Guo Wei , Li Hong‐Nan , Liu Guo‐Huan , Yu Zhi‐Wu 
Published: November 2011

AbstractIn this paper, a simplified optimization strategy for the nonlinear tuned mass damper (TMD) is presented, and the optimal parameter setting can be simply determined, by which the nonlinear TMD is effective over a wide frequency range. In the given numerical model, the nonlinear TMD is attached to the structure, which is represented by a single‐degree‐of‐freedom system, and the environmental load is assumed to be the Gaussian white noise process. Governing differential equations of motion of the coupled structure‐TMD system are derived, and the equivalent linearization method is introduced in the numerical calculation. The standard deviation of the structural displacement is adopted as the optimized objective function. Furthermore, it is pointed out that the response of the system can be controlled in a case of multiple probable steady‐state processes caused by the nonlinearity of the stiffness element. Different from the linear TMD, the performance of the nonlinear TMD may be influenced by the excitation. Thus, the performance sensitivity of optimal nonlinear TMD is investigated with different excitation intensities and structural damping ratios. The results show that the sensitivity may limit the engineering applications of nonlinear TMD.
Use of Hospital Episode Statistics to investigate abdominal aortic aneurysm surgery
Authors: Johal A , Mitchell D , Lees T , Cromwell D , van der Meulen J 
Published: November 2011

Abstract

Background
A coding framework was evaluated to study patients undergoing open surgical replacement of an abdominal aortic aneurysm (AAA) in the English Hospital Episode Statistics (HES) database. The objective was to create groups of patients who are homogeneous with respect to diagnosis, prognosis and treatment.

Methods
The frequency and consistency of potentially relevant diagnosis (International Classification of Diseases, 10th revision) and procedure (Office of Population Censuses and Surveys Classification, 4th revision) codes were assessed in patients admitted to English National Health Service hospitals between April 2003 and March 2008. Administrative codes were compared with diagnosis and procedure codes to check that patients who had undergone emergency surgery for a ruptured AAA were admitted as an emergency.

Results
Of 20 290 patients undergoing AAA replacement, 19 250 (94·9 per cent) had a consistent diagnosis (unruptured or ruptured AAA); 79·3 per cent of patients with an emergency replacement were coded as having a ruptured AAA and 95·7 per cent of those with a non-emergency replacement as having an unruptured AAA. Of patients who had undergone emergency replacement of a ruptured AAA, 93·3 per cent were coded as having been admitted as an emergency.

Conclusion
Coding consistency was high. The proposed framework could define homogeneous groups by combining diagnosis, procedure and administrative codes. It also allows an assessment of potential miscoding at national and hospital level. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
A validated LC‐MS/MS method for the determination of vinflunine in plasma and its application to pharmacokinetic studies
Authors: Pin Huang , Hong‐min Lu , Ming Ye , Qin Li 
Published: November 2011

ABSTRACTA rapid, simple and sensitive LC‐MS/MS method for the quantification of vinflunine in plasma was developed and validated. The analysis involved a simple liquid–liquid extraction. After making alkaline with NaOH, plasma was extracted with methyl tert‐butyl ether and the organic extract was then evaporated and the residue was reconstituted in mobile phase. The reconstituted solution was injected into an HPLC system and was subjected to reverse‐phase HPLC on a 5 µm ODS‐3 column at a flow‐rate of 0.2 mL/min. The mobile phase consisted of ammonium acetate (0.02 mol/L, pH = 3.0) and acetonitrile (20:80). Vinflunine was detected in the single ion monitoring mode using target ions at m/z 817.4/160.1/142.3 for vinflunine and m/z 447.2/128.3/112.1 for gefitinib (internal standard). Standard curves were linear over the concentration range of 5–1000 ng/mL. The mean predicted concentrations of the quality control samples deviated by less than 2% from the corresponding nominal values; the intra‐assay and inter‐assay precisions of the assay were within 7% relative standard deviation. The extraction recovery of vinflunine was more than 80%. The validated assay was applied to a pharmacokinetic study of vinflunine in plasma following the administration of a single vinflunine injection (2 mg/kg). Copyright © 2011 John Wiley & Sons, Ltd.
Simultaneous quantification of centchroman and its 7‐demethylated metabolite in rat dried blood spot samples using LC‐MS/MS
Authors: Lal Jawahar , Sharma Nidhi 
Published: November 2011

ABSTRACTAn approach has been developed for the quantitative determination of concentrations of centchroman (I), a nonsteroidal once‐a‐week oral contraceptive, and its major metabolite (7‐desmethyl centchroman, II) using dried blood spots (DBS) on paper, rather than conventional plasma samples. The assay employed simple solvent extraction of the DBS sample circle (6 mm) requiring small blood volumes (30 μL) followed by reversed‐phase HPLC separation, combined with multiple reaction monitoring mass spectrometric detection. The calibration plot in matrix using d‐trans‐hydroxy chroman as internal standard (IS) was linear (r2 = 0.998) over ranges of 1.5–240 and 4.5–720 ng/mL for I and II, respectively. The recoveries of both I and II were always >60% with quantification limits (signal‐to‐noise ratio = 10) of 1.5 and 4.5 ng/mL for I and II, respectively. The intra‐day and inter‐day precision (%RSD) and accuracy (%bias) variations in blood spots for both I and II were better than 13%. Moreover, both I and II were stable in DBS for at least 3 months when stored at room temperature. The developed method was successfully applied to the pharmacokinetic interaction study after oral administration of centchroman with and without co‐administration of carbamazepine in female Sprague–Dawley rats using serial sampling and results were comparable with the plasma concentrations reported earlier. Copyright © 2011 John Wiley & Sons, Ltd.
Quenching of the Luminescence of Upconverting Luminescent Nanoparticles by Heavy Metal Ions
Authors: Saleh Sayed M. , Ali Reham , Wolfbeis Otto S. 
Published: November 2011

AbstractWe report that the luminescence of upconverting luminescent nanoparticles (UCLNPs) is quenched by heavy metal ions and halide ions in aqueous solution. The UCLNPs consist of hexagonal NaYF4 nanocrystals doped with trivalent rare earth ions and were synthesized by both the oleic acid (solvothermal) method and the ethylenediaminetetraacetic acid (co‐precipitation) method. Quenching was studied for the CuII, HgII, PbII, CdII, CoII, AgI, FeIII, ZnII, bromide, and iodide ions and is found to be particularly strong for HgII. Stern–Volmer plots are virtually linear up to quencher concentrations of 10–25 mM, but deviate from linearity at higher quencher concentrations, because static quenching causes an additional effect. The UCLNPs display two main emission bands (blue, green, red or near‐infrared), and the quenching efficiencies for these are found to be different. The effect seems to be generally associated with UCLNPs because it was observed for all UCLNPs doped with trivalent lanthanide ions including YbIII, ErIII, HoIII, and TmIII. The results are discussed in terms of quenching mechanisms and with respect to potential applications such as optical sensing.
Activating Water: Important Effects of Non‐leaving Groups on the Hydrolysis of Phosphate Triesters
Authors: Kirby Anthony J. , Medeiros Michelle , Oliveira Pedro S. M. , Orth Elisa S. , Brandão Tiago A. S. , Wanderlind Eduardo H. , Amer Almahdi , Williams Nicholas H. , Nome Faruk 
Published: November 2011

AbstractThe high rate of spontaneous hydrolysis of tris‐2‐pyridyl phosphate (TPP) is explained by the activating effects of the non‐leaving (“spectator”) groups on POAr cleavage, and not by intramolecular catalysis. Previous work on phosphate‐transfer reactions has concentrated on the contributions to reactivity of the nucleophile and the leaving group, but our results make clear that the effects of the non‐leaving groups on phosphorus can be equally significant. Rate measurements for three series of phosphate triesters showed that sensitivities to the non‐leaving groups are substantial for spontaneous hydrolysis reactions, although significantly smaller for reactions with good nucleophiles. There are clear differences between triaryl and dialkyl aryl triesters in sensitivities to leaving and non‐leaving groups with the more reactive triaryl systems showing lower values for both βLG and βNLG. Intramolecular catalysis of the hydrolysis of TPP by the neighbouring pyridine nitrogens is insignificant, primarily because of their low basicity.