bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization and application of grafted polypropylene and polystyrene treated with epichlorohydrin coupled with cellulose or starch for immobilization processes
Authors: El‐Arnaouty M. B. , Eid M. , Atia K. S. , Dessouki A. M. 
Published: January 2009

AbstractThe direct‐irradiation‐induced grafting of acrylamide onto polypropylene films and polystyrene films with crosslinking epichlorohydrin (Epi) as a spacer was studied. The reaction of polyamide–Epi with cellulose and starch was carried out. Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis were carried out before and after the enzyme was immobilized to confirm the characterization of the polymer and the α‐amylase enzyme‐immobilized one. The physicochemical parameters of the immobilized enzymes were measured, and the kinetics of the coenzyme–polymer‐catalyzed reactions and stability were investigated. A direct comparison was made between the activities of the free and immobilized preparations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Aging and annealing behavior of polycarbonate surfaces modified by direct‐current glow discharge in air
Authors: Panwar Amrish K. , Barthwal S. K. , Ray S. 
Published: January 2009

AbstractAging and annealing a polycarbonate (PC) polymer surface treated by direct‐current (dc) glow discharge tend to revert it back to its virgin (pristine) state existing before surface modification by glow discharge. This structural recovery during aging and annealing has been studied in terms of the contact angles of test liquids and surface energy and correlated to the parameters of surface treatment such as the treatment time and power. Samples stored in hydrophobic environments such as air and treated by dc glow discharge at higher power levels show less recovery during aging than those treated at lower power levels. Similarly, a longer exposure time at a power level of 2.04 W decreases the extent of structural recovery in terms of surface energy during aging in air. At higher power levels, the higher kinetic energy of plasma species involved during dc glow discharge results in greater thickness of the damaged layer of the polymer surface, and so a PC sample exposed to dc glow discharge at a higher temperature also recovers at a slower rate during the initial phase of aging, whereas samples with surfaces modified by dc glow discharge at room temperature but annealed at a higher temperature show a relatively rapid recovery during the initial phase of aging. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Friction and wear behavior of glass fabric/phenolic resin composites with surface‐modified glass fabric
Authors: Su Feng‐Hua , Zhang Zhao‐Zhu 
Published: January 2009

AbstractUntreated, air‐plasma‐bombarded, and β‐aminoethyltrimethoxylsilane‐silanized glass fabric (GF) was used to prepare GF/phenolic composites by dip coating in a phenolic adhesive resin and successive curing. The tribo‐performances of these GF/phenolic composites sliding against AISI‐1045 steel were evaluated with a pin‐on‐disc wear tester. The chemical composition of the untreated and surface‐treated GF was analyzed with Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The interfacial regions between the phenolic resin and GF and the worn surfaces of the composites were analyzed with scanning electron microscopy. The results show that the GF/phenolic composite with β‐aminoethyltrimethoxylsilane‐silanized GF had the highest load‐carrying capacity and best tribo‐performance, and it was followed by the composite with plasma‐treated GF. The improved tribo‐performance of the GF/phenolic composite made of surface‐treated GF was attributed to the strengthened interfacial bonding between the treated GF and the phenolic adhesive resin. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Enhanced crystallization of poly(L‐lactide‐co‐ε‐caprolactone) in the presence of water
Authors: Saha Swapan Kumar , Tsuji Hideto 
Published: January 2009

AbstractPoly(L‐lactide‐co‐ε‐caprolactone) [P(LLA‐CL)], which is used in biodegradable biomedical materials such as drug‐delivery systems, surgical sutures, orthopedics, and scaffolds for tissue engineering, has been reported to crystallize upon storage in a dry state even at room temperature; this results in rapid changes in the mechanical properties. In biomedical applications, P(LLA‐CL) is used in the presence of water. This study investigated the effects of water on the crystallization of P(LLA‐CL) at 37°C in phosphate buffered solution, which was anticipated to alter its mechanical properties and hydrolytic degradation behavior. Surprisingly, the crystallinity of P(LLA‐CL) in the presence of water rapidly increased in 6–12 h and then slowly increased up to 120 h. The period of time for the initial rapid crystallization increase in the presence of water was much shorter than that in the absence of water. The obtained information would be useful for the selection, preparation, and use of P(LLA‐CL) in various biomedical applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Development of conducting polyaniline/poly(lactic acid) nanofibers by electrospinning
Authors: Picciani Paulo H. S. , Medeiros Eliton S. , Pan Zhongli , Orts William J. , Mattoso Luiz H. C. , Soares Bluma G. 
Published: January 2009

AbstractUltrafine fibers consisting of blends of polyaniline doped with p‐toluene sulfonic acid and poly(L‐lactic acid) were prepared by electrospinning. The presence of polyaniline resulted in fibers with diameters as thin as 100–200 nm and a significant reduction of bead formation. These fibers were visually homogeneous, and this indicated good interactions between the components of the polyaniline/poly(L‐lactic acid) blend. The high interaction between the components and the rapid evaporation of the solvent during electrospinning resulted in nanofibers with a lower degree of crystallinity in comparison with cast films. The electrical conductivity of the electrospun fiber mats was lower than that of blend films produced by casting, probably because of the lower degree of crystallinity of the polyaniline dispersion and the high porosity of the nonwoven mat. This novel system opens up new and interesting opportunities for applications in biomedical devices, biodegradable materials, and sensors, among other things. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Crosslinking reactions of oxidized cellulose fiber. II. Reactions between dialdehyde cellulose and chito‐oligosaccharides on lyocell fabric
Authors: Han Samsook , Lee Muncheul 
Published: January 2009

AbstractAntimicrobial nonfibrillated lyocell fibers were developed by crosslinking reactions between dialdehyde cellulose and chito‐oligosaccharides. Partially oxidized lyocell fibers with sodium metaperiodate were successfully crosslinked with two water‐soluble chito‐oligosaccharides with different molecular weights by Schiff base formation and were reduced with sodium borohydride. Infrared spectroscopy measurements showed the characteristic absorption bands caused by the functional groups of each reaction product. The surface chemical compositions of the modified fibers were analyzed with electron spectroscopy. O1s intensities decreased with the oxidation and crosslinking reaction, whereas N1s intensities increased with the crosslinking reaction. According to the curve fittings, C1s spectra were divided into CH, CO/CN, CO, and COO peaks, and their relative peak areas confirmed the reaction results. The degree of fibrillation of the crosslinked fibers decreased with the oxidation levels and chito‐oligosaccharide concentrations and increased with the molecular weight of the chito‐oligosaccharide. Furthermore, the chito‐oligosaccharide‐treated lyocell fibers exhibited antimicrobial activity, especially when treated with a chito‐oligosaccharide of a low weight‐average molecular weight. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of castor‐oil‐modified hyperbranched polyurethanes
Authors: Karak Niranjan , Rana Sravendra , Cho Jae Whan 
Published: January 2009

AbstractA series of castor‐oil‐modified hyperbranched polyurethanes were synthesized via an A2 + B3 approach based on castor oil, macroglycol poly(ϵ‐caprolactone)diol or poly(ethylene glycol) (PEG), and diphenyl methane diisocyanate, with or without a chain extender. The yield of the product was 95%, and the polymers were soluble in common organic polar solvents. The synthesized polymers were characterized with Fourier transform infrared spectroscopy, NMR, wide‐angle X‐ray diffraction, and gel permeation chromatography measurements. The degree of branching of the polymers was calculated from their respective 1H‐NMR spectra with the help of model compounds and found to be varied from 0.7 to 0.8. The hard‐segment content, the nature of the macroglycol, and the composition of the polymers had prominent effects on the thermal degradation and crystallization of the hyperbranched polymers. The crystallization of poly(ϵ‐caprolactone) and PEG as soft segments occurred well in the hyperbranched polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of a functional poly(ether imide) membrane for potential alkaline fuel cell applications: Chloromethylation
Authors: Wang Guigui , Weng Yiming , Zhao Jun , Chen Rongrong , Xie Dong 
Published: January 2009

AbstractWe have developed a novel poly(ether imide)‐based alkaline anion‐exchange membrane. The effects of several important parameters on the chloromethylation of the membrane have been investigated. These parameters include the reaction temperature, reaction time, concentration of the chloromethylation agent, concentration of the polymer, and amount of the catalyst. The results show that all the studied parameters have significant impacts on chloromethylation. Among them, the concentration of the chloromethylation agent plays a key role in increasing the attachment of chloromethyl functional groups onto the polymer. It ha been found that gelation can be avoided if these reaction parameters are controlled. This study also provides useful information for the successful chloromethylation of other membrane‐related polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and characterization of biodegradable polycaprolactone/multiwalled carbon nanotubes nanocomposites
Authors: Yeh Jen‐Taut , Yang Ming‐Chien , Wu Ching‐Ju , Wu Chin‐San 
Published: January 2009

AbstractBlends of the biodegradable polycaprolactone (PCL) and multiwalled carbon nanotubes (MWNTs) were prepared by means of a melt blending method. To conquer the poor compatibility between PCL and MWNTs, the acrylic acid grafted polycaprolactone (PCL‐g‐AA) and the multihydroxyl functionalized MWNTs (MWNTs‐OH) were used as alternatives for the preparation of blends. As the comparison between PCL‐g‐AA/MWNTs‐OH and PCL/MWNTs blends, the former gave much better thermal and mechanical properties than the latter; for examples, 77°C increase in the initial decomposition temperature and 13.3 MPa in the tensile strength at break with the addition of only 5 wt %, due to the formation of ester groups through the reaction between carboxylic acid groups of PCL‐g‐AA and hydroxyl groups of MWNTs‐OH. Finally, the optimal amount of MWNTs‐OH was 5 wt % because excess MWNTs‐OH caused separation of the organic and inorganic phases and lowering their compatibility. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Cure kinetics of an epoxy resin containing naphthyl/dicyclopentadiene moieties and bis‐phenoxy (3‐hydroxy) phosphine oxide system and properties of its cured polymer
Authors: Ren Hua , Sun Jianzhong , Zhao Qian , Zhiqi Cai , Ling Qincai , Zhou Qiyun 
Published: January 2009

AbstractThe cure kinetics of naphthyl/dicyclopentadiene epoxy resin and bisphenoxy (3‐hydroxy) phosphine oxide was investigated by differential scanning calorimetry (DSC) under nonisothermal and isothermal condition. The advanced isoconversional method was used to study the nonisothermal DSC data, the effective activation energy of the curing system in the early stage agreed with the value calculated from the Kissinger model and then increased because of the hindrance of molecular mobility. Autocatalytic behavior was shown in the isothermal DSC measurement, which was well described by Kamal model in the early curing stage. In the later stage, a crosslinked network structure was formed and the curing reaction was mainly controlled by diffusion. The diffusion factor was introduced to optimize the Kamal model and correct the deviation of the calculated data. The physical properties of the cured polymer were evaluated by dynamic mechanical thermal analyses, thermogravimetric analyses, and limiting oxygen index test, which exhibited relatively high glass transition temperature, thermal stability, and flame retardancy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical and thermal properties of LDPE‐cellulose acetate phthalate blends—Effect of maleic anhydride‐grafted LDPE compatibilizer
Authors: Sailaja R. R. N. , Seetharamu S. 
Published: January 2009

AbstractBiodegradable blends of LDPE and cellulose acetate phthalate have been prepared. Maleic anhydride‐grafted LDPE has been added as a compatibilizer to this blend. The elastic modulus and tensile strength has been considerably improved by adding LDPE‐g‐maleic anhydride compatibilizer. Scanning electron microscope micrographs reflected the observed results for the increase in mechanical properties of the blend. Further blend morphology exhibited a deformed matrix for the compatibilized blends. Thermogravimetric analysis studies showed two‐stage degradation for the blends. Differential scanning calorimetry thermograms showed a loss of crystallinity for the LDPE phase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Evaluation of current densities and total contact currents in occupational exposure at 400 kV substations and power lines
Authors: Korpinen Leena H. , Elovaara Jarmo A. , Kuisti Harri A. 
Published: January 2009

AbstractThis investigation studied the current densities in the neck and total contact currents in occupational exposure at 400 kV substations and power lines. Eight voluntary workers simulated their normal work tasks using the helmet–mask measuring system. In all, 151 work tasks with induced current measurements were made. Work situations were: tasks in 400 kV substations, tasks in 400–110 kV towers and the cutting of vegetation under 400 kV power lines. The average current density in the neck was estimated from the current induced in the helmet. The calculated maximum average current densities in the neck varied from 1.5 to 6.4 mA/m2 and the maximum total contact currents from 66.8 to 458.4 µA. The study shows that the maximum average current densities and the total contact currents (caused by electric field) in occupational exposure at 400 kV substations and power lines does not exceed the limit and action values (10 mA/m2 and 1 mA) of the new EU‐directive 2004/40/EC (live‐line bare‐hand works excluded). Bioelectromagnetics 30:231–240, 2009. © 2009 Wiley‐Liss, Inc.
Mobile phone use and location of glioma: A case–case analysis
Authors: Hartikka Hanna , Heinävaara Sirpa , Mäntylä Riitta , Kähärä Veikko , Kurttio Päivi , Auvinen Anssi 
Published: January 2009

AbstractWe assessed a new approach for evaluating the glioma risk among users of mobile phones to focus on the part of the brain most heavily exposed to radiofrequency electromagnetic fields from mobile phones. The tumor midpoint was defined from radiological imaging. A case–case analysis with 99 gliomas was performed using logistic regression. The exposed cases were those with the tumor mid‐point within 4.6 cm from the line between the mouth and the external meatus of the ear, representing the most likely location of the mobile phone (the source of exposure). Alternative analyses based on various indicators of mobile phone use as the outcome were also carried out. The majority of cases were regular mobile phone users. A slightly higher proportion of gliomas among mobile phone users than non‐users occurred within 4.6 cm from the presumed location of the mobile phone (28% vs. 14%). Modestly elevated odds ratios were observed for several indicators of mobile phone use, but without an exposure gradient. The highest odds ratios were found for contralateral and short‐term use. Our results, though limited by the small sample size, demonstrate that detailed information on tumor location allows evaluation of the risk related to the most heavily exposed part of the brain, representing direct evaluation of the possible local carcinogenic effects of the radiofrequency fields. However, field strength varies between users and over time also within a given anatomic site, due to the output power of the phone. Collaborative analysis of a larger sample is planned. Bioelectromagnetics 30:176–182, 2009. © 2009 Wiley‐Liss, Inc.
Enrichment of protein–RNA crosslinks from crude UV‐irradiated mixtures for MS analysis by on‐line chromatography using titanium dioxide columns
Authors: Richter Florian Martin , Hsiao He‐Hsuan , Plessmann Uwe , Urlaub Henning 
Published: January 2009

AbstractUV crosslinking is an appropriate method to identify proteins that directly contact nucleic acid, e.g., RNA. In combination with modern mass spectrometric (MS) analysis such an approach provides the opportunity to reveal not only the nature of the crosslinked proteins but also to identify the actual crosslinking sites between the protein and the nucleic acid. However, the relatively low yield in UV‐induced crosslinking makes it difficult to identify in particular those species by MS that represent peptide–nucleic acid conjugates, as the great excess of noncrosslinked material interferes with their detection in MS. Here, we present an automated enrichment strategy of crosslinked peptide–RNA oligonucleotides derived from crude mixtures of UV‐irradiated ribonucleoprotein (RNP) particles that uses TiO2 columns integrated within a two‐dimensional (2D) nanoliquid chromatography (LC) system. The setup combines two C18 precolumns, a TiO2 enrichment column and a nanoanalytical column. It allows the removal of the noncrosslinked RNA and protein moiety and the specific enrichment of crosslinked peptide–RNA conjugates so that UV‐irradiated and subsequently completely hydrolyzed RNP complexes can directly be loaded and analyzed by MS. In this feasibility study, we demonstrate the specific enrichment of peptide–RNA oligonucleotides derived from UV‐irradiated native spliceosomal U1 snRNPs and spliceosomal [15.5K‐61K‐U4atac snRNA] complex reconstituted in vitro. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 297–309, 2009.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
New biotin derivatives for labeling and solubilizing IgG peptides
Authors: Bartos Ádám , Uray Katalin , Hudecz Ferenc 
Published: January 2009

AbstractIn this article, we describe the synthesis of a new class of oligoethylene‐glycol based water‐soluble biotin derivatives for labeling of peptides with limited solubility in aqueous solution. First 4,7,10‐trioxa‐1,13‐tridecanediamine was mono‐acetylated by succinic anhydride (Ttds) followed by the introduction of N‐Fmoc‐protecting group using Fmoc‐N‐hydroxysuccinimide ester. The resulting compound (Fmoc‐Ttds) was used for the preparation of 4,7,10‐trioxa‐1,13‐tridecanediamine di‐ and trimers on solid phase using Wang resin by carbodiimide coupling method. After attachment of Fmoc‐Ttds to the solid support, the Fmoc‐blocking group was removed and the Ttds‐modified resin was repeatedly acylated by Fmoc‐Ttds or by biotin using PyBOP/HOBt active ester reaction. Finally the product [Fmoc‐(Ttds)n or biotinyl‐(Ttds)n (where n = 1, 2 or 3)] was removed from the resin by trifluoroacetic acid in the presence of water. After appropriate HPLC purification and characterization (MS) biotinyl‐(Ttds)n (where n = 1, 2 or 3) were introduced to the N‐terminal of poorly soluble oligopeptides by solid phase peptide synthesis. We found that this new class of biotinylating reagent could be prepared easily and in good yield. Comparative solubility measurements suggest that the incorporation of these moieties–depending on the number of Ttds unit–could enhance water solubility. © 2009 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 92: 110–115, 2009.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Spectral kinetic modeling and long‐term behavior assessment of Arthrospira platensis growth in photobioreactor under red (620 nm) light illumination
Authors: Farges Bérangère , Laroche Céline , Cornet Jean‐François , Dussap Claude‐Gilles 
Published: January 2009

AbstractThe ability to cultivate the cyanobacterium Arhtrospira platensis in artificially lightened photobioreactors using high energetic efficiency (quasi‐monochromatic) red LED was investigated. To reach the same maximal productivities as with the polychromatic lightening control conditions (red + blue, P/2e− = 1.275), the need to work with an optimal range of wavelength around 620 nm was first established on batch and continuous cultures. The long‐term physiological and kinetic behavior was then verified in a continuous photobioreactor illuminated only with red (620 nm) LED, showing that the maximum productivities can be maintained over 30 residence times with only minor changes in the pigment content of the cells corresponding to a well‐known adaptation mechanism of the photosystems, but without any effect on growth and stoichiometry. For both poly and monochromatic incident light inputs, a predictive spectral knowledge model was proposed and validated for the first time, allowing the calculation of the kinetics and stoichiometry observed in any photobioreactor cultivating A. platensis, or other cyanobacteria if the parameters were updated. It is shown that the photon flux (with a specified wavelength) must be used instead of light energy flux as a relevant control variable for the growth. The experimental and theoretical results obtained in this study demonstrate that it is possible to save the energy consumed by the lightening device of photobioreactors using red LED, the spectral range of which is defined according to the action spectrum of photosynthesis. This appears to be crucial information for applications in which the energy must be rationalized, as it is the case for life support systems in closed environments like a permanent spatial base or a submarine. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Application of spreadsheets in developing flexible multiple‐reach and multiple‐branch methods of Muskingum flood routing
Authors: Hosseini S.M. 
Published: January 2009

AbstractMuskingum method which is covered in most hydraulic engineering courses and textbooks is widely used for hydrologic flood routing in rivers. In this paper, computational and optimization capabilities of Microsoft Excel spreadsheet is used to perform multiple‐reach Muskingum flood routing in a river for which observed inflow and outflow hydrographs are available and its storage‐discharge relationship is highly non‐linear. The employed method is straightforward and results in better accuracy compared with traditional methods. It is also illustrated that the proposed computational procedure in the spreadsheets can be extended to flood routing in more complex river systems such as branched systems. Considering all these, from educational point of view, a main conclusion is that the results of the study significantly improve the methodologies for teaching Muskingum flood routing in complex river systems. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 448–454, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20234