bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study on composites from phenol‐formaldehyde‐casein resin
Authors: Raval Dipak K. , Vyas Sachin K. , Parmar Jitendra K. 
Published: October 2009

AbstractA modified phenol‐formaldehyde (PF) resin was synthesized under alkaline condition in varying proportion of casein up to 20% (w/w) of phenol. All the prepared resins were characterized by free phenol content, free formaldehyde content, viscosity measurements, number average molecular weight determination by conductometry and Infrared Spectroscopy (IR). Their curing kinetics was studied isothermally and by differential scanning calorimetry (DSC) on dynamic runs. The resin samples were cured using concentrated hydrochloric acid and hexamine individually. Cured resins were characterized by IR and Thermogravimetry (TGA). Glass fabric reinforced composites (GFRC) were fabricated by maintaining 40 : 60 proportion of resin to reinforcement material. The laminates thus formed were characterized for their mechanical properties and chemical resistance. Enhancements in thermal stability of the resin as well as toughness of composite with increase in casein content were observed for the resins studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Water resistance, mechanical properties, and biodegradability of poly(3‐hydroxybutyrate)/starch composites
Authors: Ismail A. M. , Gamal M. A. B. 
Published: October 2009

AbstractComposites of poly(3‐hydroxybutyrate), P(3HB), and starch were prepared by solution casting technique. To improve adhesion of starch to P(3HB), stearic acid was added as a compatibilizer and glycerol as a plasticizer. The water resistance, mechanical, and biodegradable properties of the P(3HB)/starch composites were studied. Diffusion and penetration coefficients of water increased with increasing starch content in the composites. The results showed that the elastic modulus and strain at rupture of the P(3HB)/starch composites were enhanced by increasing starch content upto 10 wt % and the tensile strength increased from 21.2 to 93.9 MPa. The presence of starch content higher than 10 wt % had an adverse effect on the mechanical properties of the investigated composites. The biodegradation rate using Actinomycetes increased proportionally to the starch content in the composite and accelerated in a culture medium of pH ≈ 7.0 at 30°C. Enzymatic degradation experiments showed that lipase produced by Streptomyces albidoflavus didnot degrade P(3HB)/starch composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Metal coordination and selectivity with oxine ligands bound to silica polyamine composites
Authors: Wong Yuen Onn , Miranda Paul , Rosenberg Edward 
Published: October 2009

AbstractA series of oxine ligands, 5‐X, 8OHC9H6N (X = H, Cl, SO3H) have been covalently bound to a silica gel polyamine composite made from a silanized amorphous silica xerogel and poly(allylamine) (BP‐1) by the Mannich reaction. The resulting modified composites WP‐4(X = H), CB‐1(X = Cl), and SB‐1(X = SO3H) were characterized by elemental analysis, FTIR, and solid state CPMAS‐13C‐NMR. Using the analytical data before and after the ligand modification, the ligand loading could be estimated and in combination with metal ion capacities a metal to ligand ratio could be obtained. The composites WP‐4 and CB‐1 both showed ratios of approximately 1 : 1 while the sulfonate modified composite, SB‐1, showed a metal to ligand ratio of 1 : 2. This is tentatively interpreted in terms of a zwitterionic oxine as the dominant species at pH = 2 where the sulfonic acid group is ionized, the quinoline nitrogen is protonated and where two sulfonate groups on adjacent oxines bind a trivalent or divalent ion. All the modified composites show a clear selectivity for trivalent over divalent ions and a good selectivity for gallium over aluminum. The substituent groups on the oxine ligand have only a minor influence on these selectivity trends but SB‐1 shows slightly better capture kinetics. The selectivity for gallium over aluminum is applied to the separation of gallium from aluminum, ferrous, and zinc in an acid ore leach of solid tailings obtained from a zinc mine using WP‐4. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation of atactic poly(vinyl alcohol)/silver composite nanofibers by electrospinning and their characterization
Authors: Lee Young Jae , Lyoo Won Seok 
Published: October 2009

AbstractPoly(vinyl alcohol) (PVA)/silver composite nanofibers were successfully prepared by the electrospinning method. Water‐based colloidal silver in a PVA solution was directly mixed without any chemical or structural modifications into PVA polymer fibers to form organic–inorganic composite nanofibers. The ratio of silver colloidal solution to PVA played an important role in the formation of the PVA/silver composite nanofibers. We prepared two different atactic PVA/silver nanocomposites with number‐average degrees of polymerization of 1700 and 4000 through electrospinning with various processing parameters, such as initial polymer concentration, amount of silver colloidal solution, applied voltage, and tip‐to‐collector distance. The PVA/silver composite nanofibers were characterized by field emission scanning electron microscopy and transmission electron microscopy (TEM). TEM images showed that silver nanoparticles with an average diameter of 30–50 nm were obtained and were well distributed in the PVA nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of a polymer/multiwalled carbon nanotube composite and its application in the hydration of ethylene oxide
Authors: Yu Fengping , Cai Hong , He Wenjun , Yang Weimin , Xie Zaiku 
Published: October 2009

AbstractMultiwalled carbon nanotubes (MWNTs) were incorporated into the crosslinking network of a styrene–divinylbenzene copolymer (PS–DVB) via suspension polymerization. The prepared crosslinking PS–DVB with MWNTs was first treated with chloromethyl methyl ether to introduce chloromethyl groups through Friedel–Craft reaction; then, the chloromethylation product was reacted with trimethyl amine to obtain the target polymer/carbon nanotube composite: PS–DVB/MWNT ion‐exchange resin. The obtained composite was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, and X‐ray photoelectron spectroscopy. The results show the successful incorporation of MWNTs into the polymer network. The physical and chemical properties of the PS–DVB/MWNT ion‐exchange resin were nearly the same as those of the controlled sample. With its excellent antiswelling properties, the catalytic behavior of the polymer composite was examined in the hydration of ethylene oxide. Also, it demonstrated excellent stability as a catalyst without a decline in conversion and selectivity in a long‐time run. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Using hydroxypropyl‐β‐cyclodextrin for the preparation of hydrophobic poly(ketoethyl methacrylate) in aqueous medium
Authors: Ding Lei , He Qinxiong , Deng Jianping 
Published: October 2009

AbstractThis work was committed to the polymerization of hydrophobic ketoethyl methacrylate monomer in aqueous medium in the presence of cyclodextrin, instead of polymerizing the monomer in toxic and volatile organic solvents. For this purpose, a new ketoethyl methacrylate monomer, p‐methylphenacylmethacrylate (MPMA), was synthesized from the reaction of p‐methylphenacylbromide with sodium methacrylate in the presence of triethylbenzylammonium chloride. The monomer was identified with FTIR, 1H and 13C‐NMR spectroscopies. Hydroxypropyl‐β‐cyclodextrin (HPCD) was used to form a water‐soluble host/guest inclusion complex (MPMA/HPCD) with the hydrophobic monomer. The complex was identified with FTIR and NMR techniques and polymerized in aqueous medium using potassium persulfate as initiator. During polymerization the resulting hydrophobic methacrylate polymer precipitated out with a majority of HPCD left in solution and a minority of HPCD bonded on the resulting polymer. The thus‐prepared polymer exhibited little difference from the counterparts obtained in organic solvent in number average molecular weight (Mn), polydispersity (Mw/Mn) and yield. The investigation provides a novel strategy for preparing hydrophobic ketoethyl methacrylate polymer in aqueous medium by using a monomer/HPCD inclusion complex. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Dependence of properties of expandable polystyrene particle foam on degree of fusion
Authors: Schellenberg Jürgen , Wallis Mario 
Published: October 2009

AbstractExpandable polystyrene (EPS) particle foams were prepared in three major steps to investigate their mechanical, thermal, and fire behavior on their degree of fusion. Bending strength was found to increase progressively, whereas compressive stress was found to increase linearly with the degree of fusion of EPS particle foams. Although at low degree of fusion the flame heights, B2 was found to decrease, it remained constant at high degree of fusion. Optical microscopic method appeared to be more reliable than pneumatic method in the determination of degree of fusion over the whole range of EPS particle foams investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Reality check: A comparison of college students and a community sample of mock jurors in a simulated sexual violent predator civil commitment
Authors: McCabe John G. , Krauss Daniel A. , Lieberman Joel D. 
Published: October 2009

AbstractDespite concerns about generalizability, past mock trial research has concluded that effects of sample (i.e., students versus representative mock jurors) are negligible. The current study was conducted to explore this conclusion within the conceptual framework of cognitive–experiential self‐theory (CEST). Through a mock civil commitment hearing of a sexually violent predator, responses of student (n = 138) and representative (n = 240) mock jurors were compared. Results revealed several important differences between samples: (a) the student sample scored higher on the rational processing measure (i.e., need for cognition); (b) students' verdicts were also significantly correlated to a measure of their cognitive processing style, an enduring personal characteristic related to the extent to which an individual engages in either effortful/effortless cognition; and (c) the representative sample was more punitive, was more persuaded by clinical expert testimony, and evidenced a greater gender effect in its decisions. Implications for jury decision‐making research are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Blind decomposition of low‐dimensional multi‐spectral image by sparse component analysis
Authors: Kopriva Ivica , Cichocki Andrzej 
Published: October 2009

AbstractA multilayer hierarchical alternating least square nonnegative matrix factorization approach has been applied to blind decomposition of low‐dimensional multi‐spectral image. The method performs blind decomposition exploiting spectral diversity and spatial sparsity between materials present in the image and, unlike many blind source separation methods, is invariant with respect to statistical (in)dependence among spatial distributions of the materials. As opposed to many existing blind source separation algorithms, the method is capable of estimating the unknown number of materials present in the image. This number can be less than, equal to, or greater than the number of spectral bands. The method is validated on underdetermined blind source separation problems associated with blind decomposition of experimental red‐green‐blue images composed of four materials. Achieved performance has been superior when compared against methods based on minimization of the ℓ1‐norm: linear programming and interior‐point methods. In addition to tumor demarcation, as demonstrated in the paper, other areas that can also benefit from the proposed method include cell, chemical, and tissue imaging. Copyright © 2009 John Wiley & Sons, Ltd.
Bis(4′‐dibutylaminostyryl)benzene: Spectroscopic Behavior upon Protonation or Methylation
Authors: Zucchero Anthony J. , Tolosa Juan , Tolbert Laren M. , Bunz Uwe H. F. 
Published: October 2009

AbstractWe have investigated the UV/Vis absorption and emission of 1,4‐bis(4′‐dibutylaminostyryl)benzene (1) upon protonation with trifluoroacetic acid in dichloromethane and in acetonitrile. We find that 1 does not display significantly dynamic acidity in the excited state, that is, it is not a photoacid. Three protonation states of 1 were investigated, all of which, neutral, singly protonated, and bis‐protonated, are fluorescent. As an isolable model for the mono‐protonated species, a methylated derivative of 1 was prepared by reaction with methyl triflate. This species displays redshifted emission but similar absorption as the non‐quaternized parent, 1. The strong observed emission of all three protonated states of 1 suggests that the kinetic photoacidity of 1* is low or absent. We assume that the lifetime of the excited state is too short to allow solvent reorganization and therefore we cannot make a statement on the thermodynamic photoacidity of the protonated forms of 1.
Synthesis of Iron Oxide Nanoparticles in Listeria innocua Dps (DNA‐Binding Protein from Starved Cells): A Study with the Wild‐Type Protein and a Catalytic Centre Mutant
Authors: Ceci Pierpaolo , Chiancone Emilia , Kasyutich Oksana , Bellapadrona Giuliano , Castelli Lisa , Fittipaldi Maria , Gatteschi Dante , Innocenti Claudia , Sangregorio Claudio 
Published: October 2009

AbstractA comparative analysis of the magnetic properties of iron oxide nanoparticles grown in the cavity of the DNA‐binding protein from starved cells of the bacterium Listeria innocua, LiDps, and of its triple‐mutant lacking the catalytic ferroxidase centre, LiDps‐tm, is presented. TEM images and static and dynamic magnetic and electron magnetic resonance (EMR) measurements reveal that, under the applied preparation conditions, namely alkaline pH, high temperature (65 °C), exclusion of oxygen, and the presence of hydrogen peroxide, maghemite and/or magnetite nanoparticles with an average diameter of about 3 nm are mineralised inside the cavities of both LiDps and LiDps‐tm. The magnetic nanoparticles (MNPs) thus formed show similar magnetic properties, with superparamagnetic behaviour above 4.5 K and a large magnetic anisotropy. Interestingly, in the EMR spectra an absorption at half‐field is observed, which can be considered as a manifestation of the quantum behaviour of the MNPs. These results indicate that Dps proteins can be advantageously used for the production of nanomagnets at the interface between molecular clusters and traditional MNPs and that the presence of the ferroxidase centre, though increasing the efficiency of nanoparticle formation, does not affect the nature and fine structure of the MNPs. Importantly, the self‐organisation of MNP‐containing Dps on HRTEM grids suggests that Dps‐enclosed MNPs can be deposited on surfaces in an ordered fashion.
Reactivity and Regioselectivity of Noble Gas Endohedral Fullerenes Ng@C60 and Ng2@C60 (Ng=He–Xe)
Authors: Osuna Sílvia , Swart Marcel , Solà Miquel 
Published: October 2009

AbstractRecently, it was shown that genuine NgNg chemical bonds are present in the endohedral fullerenes Ng2@C60 in the case of Ng=Xe, while it is more debatable whether a chemical bond exist for Ng=Ar and Kr. The lighter homologues with helium and neon are weakly bonded van der Waals complexes. The presence of a noble gas dimer inside the cage is expected to modify the exohedral reactivity of the C60 cage with respect to that of free C60. To investigate the impact of encapsulated diatomic noble gas molecules on the chemical reactivity of C60, we analyzed the thermodynamics and the kinetics of [4+2] Diels–Alder cycloaddition of 1,3‐cis‐butadiene at all nonequivalent bonds in free C60, Ng@C60, and Ng2@C60 (Ng=He, Ne, Ar, Kr, and Xe). Our BP86/TZP calculations reveal that introduction of single noble gas atoms in Ng@C60 and noble gas dimers He2 and Ne2 in Ng2@C60 has almost no effect on the exohedral reactivity compared to free C60, in agreement with experimental results. In all these cases cycloaddition is clearly favored at the [6,6] bonds in the fullerene cage. For the endohedral compounds He2@C60 and Ne2@C60 a slight preference (by less than 2 kcal mol−1) for bonds closer to the C5 symmetry axis is found. This picture changes dramatically for the endohedral compounds with heavier noble gas dimers. Encapsulation of these noble gas dimers clearly enhances the reaction, both under thermodynamic and kinetic control. Moreover, in the case of Xe2@C60, addition to [6,6] and [5,6] bonds becomes equally viable. These reactivity changes in endohedral fullerenes are attributed to stabilization of the LUMO, increased fullerene strain energy, and greater compression of the encapsulated Ng2 unit along the He to Xe series.
Ubiquitous interactive visualization of large‐scale simulations in geosciences over a Java‐based web‐portal
Authors: McLane Jonathan C. , Czech W.Walter , Yuen David A. , Knox Mike R. , Wang Shuo , Greensky Jim B. S. , Sevre Erik O. D. 
Published: October 2009

AbstractWe have designed a web‐based software system for real‐time interactive visualization of results taken from large‐scale simulations of 3‐D mantle convection and other large‐scale modeling efforts. This approach allows for intense visualization sessions for a couple of hours as opposed to storing massive amounts of data in a storage system. Our data sets consist of 3‐D data with over 10 million unknowns at each time‐step to be used for volume rendering. Large‐scale interactive visualization on a display wall holding 15 million pixels has already been accomplished. With the advent of the age of the mobile web, we have now extended this tactic to hand‐held devices, such as the OQO, Nokia N800, netbooks, iPHONE, and Android OS phones. We are developing web‐based software in Java to extend the ubiquitous use of this system across long distances. The software is aimed at creating an interactive and functional application capable of running on multiple browsers by taking advantage of two AJAX‐enabled web frameworks: Echo2 (http://echo.nextapp.com/site/echo2) and Google Web Toolkit (http://code.google.com/webtoolkit/). Modular building of the system allows for components to be swapped out so that other forms of visualization can be accommodated, such as molecular dynamics in mineral physics or 2‐D data sets from the regional convection models. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of the Self‐Assembly of 4×4 DNA Tiles by Temperature‐Dependent FRET Spectroscopy
Authors: Saccà Barbara , Meyer Rebecca , Niemeyer Christof M. 
Published: October 2009

AbstractCorrect and efficient self‐assembly of oligonucleotides into highly ordered superstructures essentially depends on the structural integrity and thermal stability of DNA motifs such as junctions or tiles that build up the superstructure. To investigate the assembly/disassembly process of DNA tiles, we recently described a microplate‐based method employing Förster resonance energy transfer (FRET) spectroscopy, which enables the analysis of DNA superstructure formation in real time and with high throughput. This method allows thermodynamic parameters of the self‐assembly process to be extracted, and we here apply it for detailed analysis of the self‐assembly of five different 4×4 DNA tile motifs. To specifically investigate whether the FRET probes tethered to the DNA motifs report local thermodynamic stabilities in the immediate proximity of the chromophores, or whether the global stability of the entire motif is monitored, systematic variations of the labeling position within one tile are carried out. Combined with gel electrophoretic, UV spectroscopic, and microcalorimetric analysis, this study reveals that the FRET method mainly reports the thermodynamics of local microenvironment assembly, rather than that of the entire motif. Nonetheless, the thermodynamic data derived from FRET analysis are also influenced by the structural surroundings of the motif, and thus rapid and detailed analysis and identification of potential “weak points” within a superstructure which influence the structural integrity of a given tile design are enabled. Therefore, the microplate FRET method readily provides insights into the assembly process of complex DNA superstructures to verify and complement theoretical design approaches.
Simultaneous Chlamydia trachomatis and HPV infection in pregnant women
Authors: Pereira Sônia Maria Miranda , Etlinger Daniela , Aguiar Luciana Silva , Peres Stela Verzinhasse , Filho Adhemar Longatto 
Published: October 2009

AbstractPregnancy is associated with HPV infection and with Chlamydia trachomatis (CT) infection mostly due to the natural immunosuppression. In addition, pregnancy associated to CT infection can lead to adverse conditions to the woman and fetus, and CT is also believed to be a co‐factor in human immunodeficiency virus infection and HPV‐induced cervical cancer. The aim of this study was to establish the odds ratios (OR) of CT infection in to HPV‐infected pregnant women and vice versa of women stratified by age (<25 years) and marital status. This work is part of a national multicentric transversal study carried out in six Brazilian cities supported by the Ministry of Health of Federal Government of Brazil in 2003. Cervical scrapes of 371 pregnant women were sampled. We performed a hybrid capture‐2 technique to diagnose these samples on HPV and CT infection, and the women responded a questionnaire. Significant association was observed between nonstable marital status and hr‐HPV infection [OR = 2.61 (1.38–4.97) P = 0.003)], and age <25 years old [OR = 2.26 (1.09–4.71) P = 0.029]. Nonstable marital status was also associated with lr‐HPV infection [OR = 2.67 (1.59–4.50) P < 0.001), and age <25 years old [OR = 2.55 (1.51–4.32) P < 0.001). Fifty of the 371 pregnant women were infected with hr‐HPV (13.5%) and 111 (30.0%) were infected with lr‐HPV. The coinfections of HPV and CT were found in 31 women, that is, 8.36% of the pregnant women (P < 0.001). The high rate of simultaneous CT and HPV infection in pregnant women favors the recommendation to screen pregnant women for both CT and HPV. Diagn. Cytopathol. 2010. © 2009 Wiley‐Liss, Inc.
Combination of liquid‐chromatography tandem mass spectrometry in different scan modes with human and chimeric mouse urine for the study of steroid metabolism
Authors: Pozo Oscar J. , Lootens Leen , Van Eenoo Peter , Deventer Koen , Meuleman Philip , Leroux‐Roels Geert , Parr Maria K. , Schänzer Wilhelm , Delbeke Frans T. 
Published: October 2009

AbstractAnabolic steroids are among the most frequently detected compounds in doping analysis. They are extensively metabolized and therefore an in‐depth knowledge about steroid metabolism is needed. In this study, a liquid chromatography tandem mass spectometry (LC‐MS/MS) method based on a precursor ion scan with a uPA‐SCID mouse with humanized liver (a chimeric mouse) was explored for the detection of steroid metabolism. Methandienone was used as a model compound. The application of the precursor ion scan method in positive human samples and chimeric mice samples after methandienone administration allowed the detection of most steroid metabolites without any structural restriction. Three hitherto unreported metabolites were found using this approach. These metabolites were characterized using LC‐MS/MS and feasible structures were proposed. The structure of one of them, 6‐ene‐epimethandienone, was confirmed by the synthesis of the reference compound. A selected reaction monitoring (SRM) method for the specific detection of all these metabolites has been developed. The application of this method to several human and chimeric mouse samples confirmed that more than 80% of the steroid metabolites were found in both samples. Only metabolites that are poorly detectable by LC‐MS/MS were not detected in some urine samples. The metabolic nature of the unreported metabolites was also confirmed. A global strategy for the detection of steroid metabolites combining both human and chimeric mouse urine is proposed. Copyright © 2009 John Wiley & Sons, Ltd.