bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and properties of bisphenol A‐based sulfonated poly(arylene ether sulfone) proton exchange membranes for direct methanol fuel cell
Authors: Zhang Ni , Li Junjing , Wang Xiangyu , Xia Zhi , Liu Huiling 
Published: June 2009

AbstractNovel bisphenol A‐based sulfonated poly(arylene ether sulfone) (bi A‐SPAES) copolymers were successfully synthesized via direct copolymerization of disodium 3,3′‐disulfonate‐4,4′‐dichlorodiphenylsulfone, 4,4′‐dichlorodiphenylsulfone, and bisphenol A. The copolymer structure was confirmed by Fourier transform infrared spectra and 1H NMR analysis. The series of sulfonated copolymers based membranes were prepared and evaluated for proton exchange membranes (PEM). The membranes showed good thermal stability and mechanical property. Transmission electron microscopy was used to obtain the microstructures of the synthesized polymers. The membranes exhibit increased water uptake from 8% to 66%, ion exchange capacities from 0.41 to 2.18 meq/g and proton conductivities (25°C) from 0.012 to 0.102 S/cm with the degree of sulfonation increasing. The proton conductivities of bi A‐SPAES‐6 membrane (0.10–0.15 S/cm) with high‐sulfonated degree are higher than that of Nafion 117 membrane (0.095–0.117 S/cm) at all temperatures (20–100°C). Especially, the methanol diffusion coefficients of membranes (1.7 × 10−8 cm2/s–8.5 × 10−7 cm2/s) are much lower than that of Nafion 117 membrane (2.1 × 10−6 cm2/s). The new synthesized copolymer was therefore proposed as a candidate of material for PEM in direct methanol fuel cell. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Morphology and thermal behavior of organo‐bentonite clay/poly(styrene‐co‐methacrylic acid)/poly(isobutyl methacrylate‐co‐4‐vinylpyridine) nanocomposites
Authors: Habi Abderrahmane , Djadoun Said , Grohens Yves 
Published: June 2009

AbstractPoly(styrene‐co‐methacrylic acid) containing 29 mol % of methacrylic acid (SMA‐29) and poly(isobutyl methacrylate‐co‐4‐vinylpyridine) containing 20 mol % of 4‐vinylpyridine (IBM4VP‐20) were synthesized, characterized, and used to elaborate binary and ternary nanocomposites of different ratios with a 3% by weight hexadecylammonium‐modified bentonite from Maghnia (Algeria) by casting method from tetrahydrofuran (THF) solutions. The morphology and the thermal behavior of these binary and ternary elaborated nanocomposites were investigated by X‐ray diffraction, scanning electron microscopy, FTIR spectroscopy, differential scanning calorimetry, and thermogravimetry. Polymer nanocomposites and nanoblends of different morphologies were obtained. The effect of the organoclay and its dispersion within the blend matrix on the phase behavior of the miscible SMA29/IBM4VP20 blends is discussed. The obtained results showed that increasing the amount of SMA29 in the IBM4VP20/SMA29 blend leads to near exfoliated nanostructure with significantly improved thermal stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Quantifying the condition of Hawaiian coral reefs
Authors: Rodgers Ku'ulei S. , Jokiel Paul L. , Bird Christopher E. , Brown Eric K. 
Published: June 2009

AbstractThis investigation developed and tested descriptive models designed to evaluate coral reef ecological condition based on data developed using the basic techniques most often used in coral reef surveys.Forty‐three variables at 184 stations were analysed in order to identify specific factors that are useful metrics for describing reef condition.The common practice of using ‘reference sites’ for paired site comparisons was evaluated by developing a reference site model (RSM). This use of reference sites proved to be subjective and unreliable, especially when multiple factors and multiple sites are involved. However, in some cases the RSM is appropriate in demonstrating severe degradation based on factors such as sediment, coral cover and fish abundance.An objective ecological gradient model (EGM) was developed based on a wide range of metrics at numerous sites. A computer program was developed that allows a quantitative ranking of reef condition along a continuum and can be used to compare reefs across a wide range of conditions. Further, this approach permits the operator to alter and define criteria appropriate to a specific question.Results of this investigation provide ecological insights into the importance of natural and anthropogenic ecological factors in determining coral reef condition. Copyright © 2009 John Wiley & Sons, Ltd.
Spatial abilities in an elective course of applied anatomy after a problem‐based learning curriculum
Authors: Langlois Jean , Wells George A. , Lecourtois Marc , Bergeron Germain , Yetisir Elizabeth , Martin Marcel 
Published: June 2009

AbstractA concern on the level of anatomy knowledge reached after a problem‐based learning curriculum has been documented in the literature. Spatial anatomy, arguably the highest level in anatomy knowledge, has been related to spatial abilities. Our first objective was to test the hypothesis that residents are interested in a course of applied anatomy after a problem‐based learning curriculum. Our second objective was to test the hypothesis that the interest of residents is driven by innate higher spatial abilities. Fifty‐nine residents were invited to take an elective applied anatomy course in a prospective study. Spatial abilities were measured with a redrawn Vandenberg and Kuse Mental Rotations Test in two (MRT A) and three (MRT C) dimensions. A need for a greater knowledge in anatomy was expressed by 25 residents after a problem‐based learning curriculum. MRT A and C scores obtained by those choosing (n = 25) and not choosing (n = 34) applied anatomy was not different (P = 0.46 and P = 0.38, respectively). Percentage of residents in each residency program choosing applied anatomy was different [23 vs. 31 vs. 100 vs. 100% in Family Medicine, Internal Medicine, Surgery, and Anesthesia, respectively; P < 0.0001]. The interest of residents in applied anatomy was not driven by innate higher spatial abilities. Our applied anatomy course was chosen by many residents because of training needs rather than innate spatial abilities. Future research will need to assess the relationship of individual differences in spatial abilities to learning spatial anatomy. Anat Sci Ed 2:107–112, 2009. © 2009 American Association of Anatomists.
Uncertainties in future projections of extreme precipitation in the Indian monsoon region
Authors: Turner A. G. , Slingo J. M. 
Published: June 2009

AbstractUncertainties in changes to the spatial distribution and magnitude of the heaviest extremes of daily monsoon rainfall over India are assessed in the doubled CO2 climate change scenarios in the IPCC Fourth Assessment Report. Results show diverse changes to the spatial pattern of the 95th and 99th subseasonal percentiles, which are strongly tied to the mean precipitation change during boreal summer. In some models, the projected increase in heaviest rainfall over India at CO2 doubling is entirely predictable based upon the surface warming and the Clausius–Clapeyron relation, a result which may depend upon the choice of convection scheme. Copyright © 2009 Royal Meteorological Society and Crown Copyright
Simultaneous quantification of five major constituents in stems of Dracaena plants and related medicinal preparations from China and Vietnam by HPLC–DAD
Authors: Fan Lan‐Lan , Tu Peng‐Fei , Chen Hu‐Biao , Cai Shao‐Qing 
Published: June 2009

AbstractA high‐performance liquid chromatographic (HPLC) method was developed for the simultaneous quantification of five major bioactive constituents in the stems of resiniferous Dracaena plants from China and Vietnam, as well as those in the related traditional Chinese medicinal preparations. A diode array detector with the wavelength of 330 nm was used to monitor resveratrol, 7,4′‐dihydroxyflavone and pterostilbene, while loureirin A and loureirin B were monitored at 280 nm. The five constituents were separated on an Agela SB C18 column by gradient elution using 0.008% (v/v) formic acid solution (A) and acetonitrile (B) as the mobile phase. The validation of the method included recovery, linearity, accuracy and precision (intra‐ and inter‐day variation). The range of recoveries of this method was 98.1–104.9%, with all the constituents showing good linearity (r2 > 0.9999). The accuracy and precision were satisfactory, with the overall intra‐ and inter‐day variation being less than 4%. The present method has been successfully applied for the determination of all five constituents in 21 related herbal samples including 10 D. cochinchinensis stem samples, seven D. cambodiana stem samples and four purchased medicinal preparations. The contents of these constituents were analyzed using principal component analysis, which can efficiently identify raw herb of Dracaena from different sources. The study may be considered helpful to the quality control of Dracena plants and its medicinal preparations. Copyright © 2009 John Wiley & Sons, Ltd.
Tailored carbon nanotubes for tissue engineering applications
Authors: Veetil Jithesh V. , Ye Kaiming 
Published: June 2009

AbstractA decade of aggressive researches on carbon nanotubes (CNTs) has paved way for extending these unique nanomaterials into a wide range of applications. In the relatively new arena of nanobiotechnology, a vast majority of applications are based on CNTs, ranging from miniaturized biosensors to organ regeneration. Nevertheless, the complexity of biological systems poses a significant challenge in developing CNT‐based tissue engineering applications. This review focuses on the recent developments of CNT‐based tissue engineering, where the interaction between living cells/tissues and the nanotubes have been transformed into a variety of novel techniques. This integration has already resulted in a revaluation of tissue engineering and organ regeneration techniques. Some of the new treatments that were not possible previously become reachable now. Because of the advent of surface chemistry, the CNT's biocompatibility has been significantly improved, making it possible to serve as tissue scaffolding materials to enhance the organ regeneration. The superior mechanic strength and chemical inert also makes it ideal for blood compatible applications, especially for cardiopulmonary bypass surgery. The applications of CNTs in these cardiovascular surgeries led to a remarkable improvement in mechanical strength of implanted catheters and reduced thrombogenecity after surgery. Moreover, the functionalized CNTs have been extensively explored for in vivo targeted drug or gene delivery, which could potentially improve the efficiency of many cancer treatments. However, just like other nanomaterials, the cytotoxicity of CNTs has not been well established. Hence, more extensive cytotoxic studies are warranted while converting the hydrophobic CNTs into biocompatible nanomaterials. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Direct measurement of the kinetics of CBM9 fusion‐tag bioprocessing using luminescence resonance energy transfer
Authors: Kavoosi Mojgan , Creagh A. Louise , Turner Robin F. B. , Kilburn Douglas G. , Haynes Charles A. 
Published: June 2009

AbstractThe economics of affinity‐tagging technologies, particularly at preparative scales, depends in part on the cost and efficiency of the bioprocessing step used to remove the affinity tag and obtain the final purified product (Lowe et al., J Biochem Biophys Methods. 2001;49:561–574). When CBM9, the family 9 cellulose binding module from Thermotoga maritima, serves as the affinity tag, the overall efficiency of tag removal is a function of the choice of processing enzyme and the local structure of the cleavage site, most notably the linker sequence flanking the bioprocessing recognition site on the tag side. A novel spectroscopic method is reported and used to rapidly and accurately measure CBM9 fusion‐tag bioprocessing kinetics and their dependence on the choice of linker sequence. The assay monitors energy transfer between a lanthanide‐based donor bound to the CBM9 tag and an acceptor fluorophore presented on the target protein or peptide. Enzyme‐catalyzed cleavage of the fusion tag terminates this resonance energy transfer, resulting in a change in fluorescence intensity that can be monitored to quantify substrate concentration over time. The assay is simple, fast and accurate, providing kcat/KM values that contain standard errors of less than 3%. As a result, both substantial and subtle differences in bioprocessing kinetics can be measured and used to guide bioproduct design. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
N‐way morphing for 2D animation
Authors: Baxter William , Barla Pascal , Anjyo Ken 
Published: June 2009

AbstractWe present a novel approach to the creation of varied animations from a small set of simple 2D input shapes. Instead of providing a new 2D shape for each keyframe of an animation sequence, we interpolate between a few example shapes in a reduced pose‐space. Similar approaches have been presented in the past, but were restricted in the types of input or range of deformations allowed. In order to address these limitations, we reformulate the problem as an N‐way morphing process on 2D input bitmap or vector graphics. Our formulation includes an N‐way mapping technique, an efficient, rigidity preserving nonlinear blending function, improved extrapolation and a novel scattered data interpolation technique to manage the reduced pose‐space. The resulting animations are correlated to paths in the reduced pose‐space, allowing users to intuitively and interactively control temporal behaviours with simple gestures. We demonstrate our techniques in several example animations. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of Protein–Protein Interactions by Using Droplet‐Based Microfluidics
Authors: Srisa‐Art Monpichar , Kang Dong‐Ku , Hong Jongin , Park Hyun , Leatherbarrow Robin J. , Edel Joshua B. , Chang Soo‐Ik , deMello Andrew J. 
Published: June 2009

AbstractEvery little drop: The KD values of angiogenin (ANG) interactions as shown by FRET analysis of thousands of pL‐sized droplets agree with data from bulk‐fluorescence polarization measurements. Importantly, the use of fluorophores does not affect the activity of ANG or the binding of anti‐ANG antibodies to ANG. Such an experimental platform could be applied to the high‐throughput analysis of protein–protein interactions.magnified image
Epoxide‐Hydrolase‐Initiated Hydrolysis/Rearrangement Cascade of a Methylene‐Interrupted Bis‐Epoxide Yields Chiral THF Moieties without Involvement of a “Cyclase”
Authors: Ueberbacher Barbara T. , Oberdorfer Gustav , Gruber Karl , Faber Kurt 
Published: June 2009

AbstractCyclase‐free at last: A methylene‐interrupted meso‐bis‐epoxide was stereoselectively converted into dihydroxy‐tetrahydrofuran derivatives with excellent de and ee values through an enzyme‐triggered nucleophilic hydrolysis/cyclisation cascade. Molecular modelling showed that the point of enzyme attack was determined by the stereospecificity of the epoxide hydrolase, whereas the stereochemical course of the cyclisation step was solely governed by Baldwin's rules and did not invoke the involvement of a “cyclase”.magnified imageIn contrast with electrophilic enzyme‐catalysed cyclisations in terpenoid biosynthesis, cyclisations of tetrahydrofuran moieties found in several groups of natural products, such as annonaceous acetogenins, neurofurans and phytooxylipins, appear to proceed through a nucleophilic cascade mechanism starting from bis‐epoxy fatty acid precursors. This hypothesis was verified by epoxide‐hydrolase‐catalysed hydrolytic ring‐opening/cyclisation cascades starting from a methylene‐interrupted meso‐bis‐epoxide model substrate, which furnished the corresponding THF products with excellent de and ee values. Molecular modelling showed that the points of enzyme attack were consistent with the stereospecificities of the enzymes, whereas the stereochemical courses of the cyclisation were solely governed by Baldwin's rules and did not invoke the involvements of a “cyclase”.
Synthesis of enantiomers ofexo‐2‐norbornyl‐N‐n‐butylcarbamate andendo‐2‐norbornyl‐N‐n‐butylcarbamate for stereoselective inhibition of acetylcholinesterase
Authors: Chiou Shyh‐Ying , Huang Chuan‐Fu , Yeh Shyh‐Jei , Chen I‐Ru , Lin Gialih 
Published: June 2009

AbstractThe acetylcholinesterase inhibition by enantiomers ofexo‐ andendo‐2‐norbornyl‐N‐n‐butylcarbamates shows high stereoselelectivity. For the acetylcholinesterase inhibitions by (R)‐(+)‐ and (S)‐(−)‐exo‐2‐norbornyl‐N‐n‐butylcarbamates, theR‐enantiomer is more potent than theS‐enantiomer. But, for the acetylcholinesterase inhibitions by (R)‐(+)‐ and (S)‐(−)‐endo‐2‐norbornyl‐N‐n‐butylcarbamates, theS‐enantiomer is more potent than theR‐enantiomer. Optically pure (R)‐(+)‐exo‐,(S)‐(−)‐exo‐, (R)‐(+)‐endo‐, and (S)‐(−)‐endo‐2‐norbornyl‐N‐n‐butylcarbamates are synthesized from condensations of optically pure (R)‐(+)‐exo‐,(S)‐(−)‐exo‐, (R)‐(+)‐endo‐, and (S)‐(−)‐endo‐2‐norborneols withn‐butyl isocyanate, respectively. Optically pure norborneols are obtained from kinetic resolutions of their racemic esters by lipase catalysis in organic solvent. Chirality 2010. © 2009 Wiley‐Liss, Inc.
Optische Extinktionsmessverfahren zur Inline‐Kontrolle disperser Stoffsysteme
Authors: Steinke L. , Wessely B. , Ripperger S. 
Published: June 2009

AbstractOptische Messverfahren besitzen neben der vielseitigen Einsetzbarkeit den Vorteil, dass sie berührungslos und rückwirkungsfrei Stoffsysteme vermessen können. Sie werden häufig zur Partikelanalyse eingesetzt und sind in diesem Zusammenhang auch für die Überwachung von Prozessen interessant, bei denen disperse Stoffsysteme erzeugt, verändert oder separiert werden. Im Folgenden werden die Grundlagen der optischen Extinktionsmesstechnik zur Partikelanalyse beschrieben und Messsysteme vorgestellt, die es erlauben, mehrere Zustandsgrößen eines Partikelsystems aufgrund der Extinktionsmessung zu erfassen.
Stofftransportprozesse in Blasensäulen und Stabilisierung von organischen Nanopartikeln mit verschiedenen Tensiden
Authors: Hermeling M. , Weber A. P. 
Published: June 2009

AbstractUntersucht wurde der Transport gasgetragener Partikel in unterschiedliche Tensidlösungen in einer Einzelblasenkammer. Insbesondere wurde der Einfluss der sich oberhalb der Flüssigkeit ausbildenden Schaumschicht charakterisiert, die im Wesentlichen die Partikelkonzentration in der Suspension erhöht. Zudem hat die Wahl des Tensids einen signifikanten Einfluss auf die Partikelkonzentration in der Suspension.
Impaktion und Abspringen von Nanopartikel‐Agglomeraten bei der Trockendispergierung
Authors: Wu T. , Weber A. P. 
Published: June 2009

AbstractUm die größenabhängigen Eigenschaften von Nanopartikeln zu nutzen, kann eine Trockendispergierung hilfreich sein. In der vorliegenden Arbeit wurde die Trockendispergierung von industriellen Aerosil®‐Nanopulvern untersucht. Dabei zeigte sich, dass eine Vielzahl von Prozessen parallel abläuft, die zum Teil als Informationsquelle zu den einzelnen Schritten der Trockendispergierung verwendet werden können.
Verbesserung der Fließfähigkeit feiner kohäsiver Pulver durch nanoskalige Fließhilfsmittel
Authors: Kleinschmidt S. , Tomas J. 
Published: June 2009

AbstractDie überwiegende Zahl mineralischer Rohstoffe und Konzentrate, Hilfsstoffe, landwirtschaftlicher und synthetischer disperser Feststoffprodukte wird in Partikelgrößen kleiner als 100 μm erzeugt. Diese feinen Pulver weisen eine Reihe recht problematischer Produkteigenschaften auf. Ihre interpartikulären Haftkräfte, insbesondere die Van‐der‐Waals‐Kräfte, übersteigen die Gewichtskräfte um mehrere Größenordnungen. Die störungsfreie Handhabung dieser Produkte stellt daher ein großes Problem und eine wissenschaftlich‐technische Herausforderung dar. Ihre physikalischen Eigenschaften, insbesondere die Fließfähigkeit, sind jedoch für viele Industriezweige der Erzeugung, Weiterverarbeitung, Anwendung und des Verbrauchs, beispielsweise in der Pharmaindustrie, Lebensmittelindustrie, chemischen Industrie oder im Maschinen‐ und Anlagenbau, besonders bedeutsam. Eine seit Jahrzehnten häufig praktizierte Lösungsmöglichkeit besteht im Zusatz geringer Mengen sogenannter Fließhilfsmitteln, die die Fließfähigkeit feiner kohäsiver Pulver deutlich verbessern sollen. Diese Publikation gibt eine Übersicht über die physikalisch‐chemischen Wirkprinzipien der Fließhilfsmittel, die beschreibenden Modellvorstellungen und die einschlägigen Bewertungsmethoden der Fließfähigkeit. Anhand einiger typischer Messreihen aus der Literatur werden die Wirksamkeit der Zugabe von Nanopartikeln und Tensiden kritisch diskutiert und Schlussfolgerungen für deren verfahrenstechnische Anwendbarkeit gezogen.
Reaction accompanied mass transfer from fluid and solid spheres at low reynolds numbers
Authors: Johnson A. I. , Akehata T. 
Published: June 2009

AbstractReaction accompanied mass transfer from fluid and solid spheres has been studied for creeping flow and a first order reaction.The results are presented graphically as Sherwood number plotted against Peclet number, with a dimensionless reaction rate factor as a parameter. At high values of the Peclet number the results approach the curves for physical mass transfer, while at low Peclet numbers the results may be predicted by the equations for reaction accompanied diffusions.The results were obtained by Yuge's method and by finite‐difference numerical methods. The latter methods had limited ranges of applicability.
The dynamics of reactors of mixed type: I. The nature of the steady state
Authors: Gall C. E. , Aris R. 
Published: June 2009

AbstractThe steady state of a reactor consisting of a tubular reactor followed by a stirred tank with material and thermal feedback is invesigated here. It is found that the overall heat generation curve can be considerably more complex than that of a single stirred tank on account of the backmixing and feedback. The influence of these effects on the stability of the reactor is discussed.
Operating lines in cascade separation of binary mixtures
Authors: Hwang S‐T. , Kammermeyer Karl 
Published: June 2009

AbstractThe general case of cascade operation is treated without any restriction on the value of the separation factor. Equilibrium curves are briefly discussed. These are generally a function of the cut.The equations of operating lines for both of enriching and stripping sections are derived for the general case by appropriate material balances. Also, three specific applications are presented in detail, by showing graphical constructions and discussing characteristic features for each case.
Hydrates in the methane‐nitrogen system
Authors: Jhaveri Jaysukh , Robinson Donald B. 
Published: June 2009

AbstractThe gas hydrate equilibrium curves for systems containing methane and nitrogen have been obtained in the temperature interval 32°F. to 72°F. and between pressures of 350 and 5100 Ib./sq.in.abs. The composition of the equilibrium gas and hydrate phases was determined experimentally at 32°F. and 44°F. This information was used to calculate vapor‐solid equilibrium ratios for both nitrogen and methane. A comparison is made between the equilibrium ratios in this system which crystallizes in Structure I and the ratios in systems reported earlier which crystallize in Structure II.
The prediction of binary adsorption equilibria from pure component isotherms
Authors: Cook W. H. , Basmadjian D. 
Published: June 2009

AbstractA semi‐empirical method is proposed for the prediction of adsorption equilibria of binary gas mixtures from pure component isotherms, including and extending beyond the range of validity of previous methods. It is based on an expression, derived earlier by one of the authors(1) which relates the binary separation factor α to the pure component pressure ratio at constant volume adsorbed.The method permits the quantitative calculation of the binary isotherms, V1 = f1 (p1) and V2 = f2 (p2), in the entire range of mono‐molecular adsorption, and yields predicted values in good agreement with experimental data for a variety of systems in the range 75°‐363°K and total pressures up to 35 atm.