bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on thermo‐rheological properties and stability of SBR modified asphalts containing palygorskite clay
Authors: Zhang Ji , Wang Junlong , Wu Yiqian , Sun Wenxiu , Wang Yunpu
Published: April 2009

One problem of polymer‐modified asphalts (PMAs) is the poor compatibility between polymer and asphalts. In this article, the effects of palygorskite clay (PC) and organomodified palygorskite clay (OPC) on the rheological and morphological properties of styrene butadiene rubber (SBR) modified asphalts are investigated. The dynamic mechanical analysis (DMA) of PC and SBR/PC (OPC) modified asphalts before and after ageing has been characterized by dynamic shear rheometer (DSR). The results indicate that the degree of SBR modification is a function of asphalt‐polymer compatibility. When the polymer concentration is higher, it produces a highly elastic network which increases the viscosity, complex modulus, and elastic response of the mixture, particularly at high service temperatures. However, ageing of the SBR and SBR‐PC mixtures result in a decrease in the elastic response of the modified asphalts. It also have been confirmed that the morphology observed by optical microscopy and scanning electron microscope (SEM) revealed the better compatibility between SBR/PC and asphalt. The storage stability of binder is improved significantly. Compared with PC, OPC shows better effect in improving viscoelastic properties and rutting resistance of the mixture, which contributes to the better improvement of interfacial adhesion based on larger size between layers in OPC‐modified asphalts. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and properties of poly(urethane‐imide) diacid/epoxy composites cured with an aziridine system
Authors: Liu Pinggui , Zhang Qingfang , He Lihua , Xie Qingji , Ding Heyan
Published: April 2009

A poly(urethane‐imide) diacid (PUI), a diimide‐diacid with a soft structure unit, was directly synthesized from the reaction of trimellitic anhydride and isocyanate terminated polyurethane prepolymer. FT‐IR and NMR were used to characterize its chemical structure. Then PUI was blended with two types of epoxy resins with different chemical structures, diglycidyl ether of bisphenol A (DGEBA) and novolac epoxy (EPN). After curing the blends with polyfunctional aziridine CX‐100, novel polyurethane/epoxy composites were obtained as transparent yellowish films. Thermal, chemical, and morphological properties of the cured composites were investigated using thermal analysis, SEM, TEM, chemical resistance, respectively. All experimental data indicated that epoxy modified PUI composites possessed higher thermal stability than that unmodified PUI, and that modified PUI had much better chemical resistance. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Novel self‐supported natural and synthetic polymer membranes for air humidification
Authors: Bhat S.D. , Manokaran A. , Sahu A.K. , Pitchumani S. , Sridhar P. , Shukla A.K.
Published: April 2009

Novel self‐supported natural and synthetic polymer membranes of chitosan‐hydroxy ethyl cellulose‐montmorillonite (CS‐HEC‐MMT) and polyvinyl alcohol (PVA)‐polystyrene sulfonic acid (PSSA) are prepared by solution casting method followed by crosslinking. These membranes are employed for air humidification at varying temperatures between 30°C and 70°C and their performances are compared with commercial Nafion® membranes. High water fluxes with desired humidified‐air output have been achieved for CS‐HEC‐MMT and PVA‐PSSA hybrid membranes at air‐flow rates of 1–10 slpm. Variation in the air/water mixing ratio, dew point, and relative humidity that ultimately results in desired water flux with respect to air‐flow rates are also quantified for all the membranes. Water flux values for CS‐HEC‐MMT are less than those for Nafion® and PVA‐PSSA membranes, but the operational stability of CS‐HEC‐MMT membrane is higher than PVA‐PSSA and comparable with Nafion® both of which can operate up to 70°C at repetitive cycles of humidification. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of acrylic core–shell rubber particles on the particulate flow and toughening of PVC
Authors: Moghbeli M. R. , Tolue Sh.
Published: April 2009

Different types of acrylic core–shell rubber particles with a poly(butyl acrylate) (PBA) core and a grafted poly(methyl methacrylate) (PMMA) shell were synthesized. The average size of acrylic core–shell latex particles ranged from 100 to 170 nm in diameter, having the core gel content in the range of 35–80%. The melt blending behavior of the poly(vinyl chloride) (PVC) and the acrylic core–shell rubber materials having different average particle sizes and gel contents was investigated in a batch mixing process. Although the torque curves showed that the particulate flow of the PVC in the blends was dominant, some differences were observed when the size and gel content of the particles varied. This behavior can be attributed to differences in the plasticizing effect and dispersion state of various types of core–shell rubber particles, which can vary the gelatin process of the PVC in the mixing tool. On the other hand, the highest toughening efficiency was obtained using core–shell rubber particles with the smallest particle size (i.e., 100 nm). The results showed that increasing the gel content of the core–shell impact modifiers with the same particle size improved the particle dispersion state in the PVC matrix. The toughening efficiency decreased for the blends containing 100 and 170 nm rubber particles as the gel content increased. Nevertheless, unexpected behavior was observed for the blends containing 140 nm rubber particles. It was found that a high level of toughness could be achieved if the acrylic core–shell rubber particles as small as 100 nm had a lower gel content. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Dynamic mechanical and morphological behavior of blends of polystyrene and poly[acrylonitrile‐g‐(ethylene‐co‐propylene‐co‐diene)‐g‐styrene] prepared by in situ polymerization of styrene
Authors: Lourenço Emerson , Gonçalves Maria do Carmo , Felisberti Maria Isabel
Published: April 2009

PS/AES blends were prepared by in situ polymerization of styrene in the presence of AES elastomer, a grafting copolymer of poly(styrene‐co‐acrylonitrile) – SAN and poly(ethylene‐co‐propylene‐co‐diene)–EPDM chains. These blends are immiscible and present complex phase behavior. Selective extraction of the blends' components showed that some fraction of the material is crosslinked and a grafting of PS onto AES is possible. The morphology of the noninjected blends consists of spherical PS domains covered by a thin layer of AES. After injection molding, the blends show morphology of disperse elastomeric phase morphology in a rigid matrix. Two factors could contribute to the change of morphology: (1) the stationary polymerization conditions did not allow the mixture to reach the equilibrium morphology; (2) the grafting degree between PS and AES was not high enough to ensure the morphological stability against changes during processing in the melting state. The drastic change of EPDM morphology from continuous to disperse phase has as consequence a decrease in the intensity of the loss modulus peaks corresponding to the EPDM glass transition. However, the storage modulus at temperatures between the glass transition of EPDM and PS/SAN phases does not change significantly. This effect was attributed to the presence of the SAN rigid chains in the AES. © 2009 Wiley Periodicals, Inc. Journal of Applied Polymer Science, 2009
Effect of polymer additives and process temperature on the physical properties of bitumen‐based composites
Authors: Doğan Mehmet , Bayramli Erdal
Published: April 2009

Polymer modified bitumen (PMB) is a binder obtained by the incorporation of polymer into the bitumen by mechanical mixing or chemical reaction. This study deals with the modification of bitumen with three types of polymers (LDPE, EVA, and SBS) in the presence of filler (CaCO3). The morphological, mechanical, rheological properties, and thermal conductivity of the PMBs have been analyzed by scanning electron microscopy, tensile testing, melt flow index (MFI) measurements and hot wire method, respectively. The results indicate that the above‐mentioned properties of PMBs are influenced by polymer and bitumen nature and its composition. The mechanical properties of composites prepared at different temperatures exhibit small differences. In general, the inclusion of polymer increases tensile strength and Young's modulus and reduces percentage strain and MFI values, also, polymer inclusion reduces the thermal conductivity values of the composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Sulfonated poly(ether sulfone)‐based catalyst binder for a proton‐exchange membrane fuel cell
Authors: Krishnan N. Nambi , Kim Hyoung‐Juhn , Jang Jong Hyun , Lee Sang‐Yeop , Cho EunAe , Oh In‐Hwan , Hong Seong‐Ahn , Lim Tae‐Hoon
Published: April 2009

Sulfonated poly(ether sulfone) copolymer (PES 60) and its partially fluorinated analogue (F‐PES 60) were synthesized via the nucleophilic aromatic polycondensation of commercially available monomers to make a polymer electrolyte membrane and a binding material in the electrodes of a membrane–electrode assembly (MEA). PES 60 and F‐PES 60 showed proton conductivities of 0.091 and 0.094 S/cm, respectively, in water at room temperature. The copolymer was dissolved in the mixture of alcohol and water to get a 1 wt % binder solution. A catalyst slurry was prepared with the copolymer solution and sprayed on the copolymer (PES 60 or F‐PES 60) membrane to obtain a MEA. Both PES 60 and F‐PES 60 based MEAs were fabricated with different amounts of their binder in the electrodes to examine the effect of the copolymer binder in the catalyst layer on the fuel cell performance. The MEA with 2 wt % copolymer binder in the electrodes showed the best fuel cell performance. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Transglutaminase‐mediated crosslinking of gelatin onto wool surfaces to improve the fabric properties
Authors: Cui Li , Wang Qiang , Wang Ping , Huan Qingsong , Fan Xuerong
Published: April 2009

In this study, transglutaminase (TGase)‐mediated crosslinking of gelatin on the surface of wool and its effect on the properties of wool fabric were investigated. For the wool fabric used in this study, gelatin (3 g/L) treatment for 1 h combined with 20 U/g of fabric microbial TGase reduced the area shrinkage of KMnO4‐pretreated wool fabric from 6.53 ± 0.06 to 1.92 ± 0.15%, which was more effective than that treated with gelatin alone (in which the area shrinkage was reduced to 4.02 ± 0.10%). At the same time, the tensile strength recovered from 267 ± 2.0 to 335 ± 2.1 N. The antifelting ability of treated wool fabric exhibited better washing durability. Scanning electron micrographs showed that the gelatin material smoothed the wool fiber surface by coating or filling the raised scales of the wool with TGase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Physicochemical characterization of a pectin/calcium matrix containing a large fraction of calcium chloride: Implications for sigmoidal release characteristics
Authors: Wei Xiuli , Chen Zhukang , Lu Yi , Xu Huinan , Chen Guiliang , Wu Wei
Published: April 2009

The physicochemical properties of pectin/calcium matrix tablets were studied with an emphasis on the effect of over 50% of calcium chloride to better understand the fundamentals of the drug‐release mechanisms. The absence of the adsorption of methylene blue onto the calcium‐containing pectin matrix served as evidence of the calcium‐ion‐induced in situ crosslinking of pectin chains. Visual and scanning electron microscopy observation showed the reinforced robustness of the pectin/calcium matrix, whereas cryo‐SEM revealed the formation of a pectin aggregate network as a result of calcium‐induced crosslinking. The aggregate network underwent gradual erosion to a lower density, which indicated the erosion of the matrix. However, little change in the texture of the pectin/calcium matrix was observed at earlier times, which was interpreted as the initial stages of drug‐release retardation. The apparent viscosity of the pectin aqueous dispersion increased biphasically as the calcium amount increased. The initial sharp increase was interpreted as calcium‐induced crosslinking, whereas the following gradual increase was ascribed to a possible salt effect. We concluded that the salt effect and calcium‐induced crosslinking contributed to a series of physical changes of the pectin matrix, which correlated to the sigmoidal release of indomethacin from the pectin/calcium matrix tablet. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of molecularly imprinted polymer films on monodisperse macromolecular beads
Authors: Zheng Ximing , Tu Weiping , Fan Rongyu
Published: April 2009

A new and facile technique for preparing homogeneous and highly selective molecularly imprinted polymers (MIPs) films on porous monodisperse poly‐(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) beads (PGMA‐EDMA beads) has been described: before polymerization, initiator was immobilized on the PGMA‐EDMA beads' surface by chemical reactivity; then functional monomers and crosslinkers were initiated by the surface‐bound initiator and copolymerized to form MIPs films on the PGMA‐EDMA beads' surface in the presence of template molecules. The resulting beads were analyzed by FTIR spectroscopy and X‐ray photoelectron spectra. The effects of the initiator amount and copolymerization time on the content of MIPs, and MIPs contents on morphologies and pore properties of the resulting beads were investigated. The results show that the content of MIPs can be adjusted by changing initiator amount or by controlling copolymerization time. The binding experiments indicate that, at lower grafting level, with the increase of MIPs content, the adsorption and recognition capabilities of the resulting beads enhance. When MIPs content increase to 16.75%, the highest adsorption and recognition capabilities are obtained. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of polyacrylamide aqueous dispersions using poly(sodium acrylic acid) as stabilizer
Authors: Liu Xiaoguang , Chen Qiang , Xu Kun , Zhang Wende , Wang Pixin
Published: April 2009

High‐solids, low‐viscosity, stable polyacrylamide (PAM) aqueous dispersions were prepared by dispersion polymerization of acrylamide in aqueous solution of ammonium sulfate (AS) using poly (sodium acrylic acid) (PAANa) as the stabilizer, ammonium persulfate (APS) or 2,2′‐Azobis (N,N′‐dimethyleneisobutyramidine) dihydrochloride (VA‐044) as the initiator. The molecular weight of the formed PAM, ranged from 710, 000 g/mol to 4,330,000 g/mol, was controlled by the addition of sodium formate as a conventional chain‐transfer agent. The progress of a typical AM dispersion polymerization was monitored with aqueous size exclusion chromatography. The influences of the AS concentration, the poly(sodium acrylic acid) concentration, the initiator type and concentration, the chain‐transfer agent concentration and temperature on the monomer conversion, the dispersion viscosity, the PAM molecular weight and distribution, the particle size and morphology were systematically investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Analysis of crack phenomenon for injection‐molded screw using moldflow simulation
Authors: Shin Hyeyoung , Park Eun‐Soo
Published: April 2009

The screw for ice water filter machine was injection molded with acrylonitrile–butadiene–styrene (ABS)/polycarbonate (PC) [ABS/PC] alloy resin and its crack phenomenon after mechanical stress was analyzed by commercial Moldflow software. The cracked morphology and tensile properties of ABS/PC have been studied by scanning electron microscopy (SEM) and universal test machine (UTM). The injection pressure and the residual stress has been compared with two injection molding conditions as actual manufacturing and reduced injection flow rate. This analysis has found that residual stress is higher at actual manufacturing condition. SEM study reveals that in the micrographs taken on the surface of cracked sample ABS rubber domains tend to extremely align in the direction of mold flow. The combined data suggest that the majority of the crack comes from residual stress in final part originated from higher injection pressure during injection‐molding process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A comparative study on the electrical and mechanical behaviour of multi‐walled carbon nanotube composites prepared by diluting a masterbatch with various types of polypropylenes
Authors: Mičušík Matej , Omastová Mária , Krupa Igor , Prokeš Jan , Pissis Polycarpos , Logakis Emmanuel , Pandis Christos , Pötschke Petra , Pionteck Jürgen
Published: April 2009

Polypropylene (PP) nanocomposites with multi‐walled carbon nanotubes (CNT) were produced by a small‐scale masterbatch melt dilution technique using five PP differing in melt flow index (MFI) and degree of maleination. PP used in a masterbatch has MFI = 12 (PP12), the others used PP which have MFI = 2 or MFI = 8. The state of CNT dispersion as assessed by melt rheological and morphological investigations indicated a better dispersion when using unmodified PP with MFI = 8 (PP8) and the masterbatch's PP12. Electrical conductivity results showed nanotube percolation at contents between 1.1 and 2.0 vol %, whereas lower values were obtained for the matrices with the best dispersion, i.e., PP8 and PP12. The dependencies of the relative Young's modulus on the CNT content showed that the maleinization improved the interfacial interactions between the components, especially in the case of maleated PP with MFI = 8 (PP‐MA8), but the better dispersion was prevented by the incompatibility between polar groups of PP‐MA and the nonpolar origin masterbatch PP12. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Delay‐dependent H∞ control of parameter‐varying delayed systems via parameter‐dependent Lyapunov function approach
Authors: Zhou Shaosheng , Zheng Wei Xing
Published: April 2009

The H∞ control problem of parameter‐varying delayed systems is investigated in this paper. The state‐space matrices of the systems are assumed to be dependent on a vector of time‐varying real parameters which are assumed to be real‐time measurable. The delays related to the parameter‐varying systems are assumed to be unknown but with known upper bounds and to be in the states and control inputs. A delay‐dependent H∞ performance condition of the system under consideration is derived by using a new parameter‐dependent Lyapunov function. Based on the H∞ performance condition, a linear matrix inequality (LMI) based H∞ control strategy is proposed by using auxiliary variable technique. The combined parameter‐dependent and delay‐dependent results are less conservative due to the generality of the parameter‐dependent and delay‐dependent Lyapunov function used, which includes the parameter‐independent one as a special case. It is shown that the underling H∞ control problem can be solved as LMI optimization problems that can be numerically computed very efficiently. A numerical example is also given to demonstrate the applicability of the proposed approach. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Video‐rate scanning probe control challenges: setting the stage for a microscopy revolution
Authors: Rost M. J. , van Baarle G. J. C. , Katan A. J. , van Spengen W. M. , Schakel P. , van Loo W. A. , Oosterkamp T. H. , Frenken J. W. M.
Published: April 2009

Scanning probe microscopy is at the verge of revolutionizing microscopy once again. Video‐rate scanning tunneling microscope (STM) and video‐rate atomic force microscope (AFM) technology will enable the direct observation of many dynamic processes that are impossible to observe today, such as atom or molecule diffusion, real time film growth, or catalytic reactions. In this paper we discuss the critical aspects that have to be taken into account when working on increasing the imaging speed of scanning probe microscopes. We highlight the state‐of‐the‐art developments in the control of the piezoelectric scanning elements and describe the latest innovations regarding the design and construction of the whole mechanical loop including new scanner geometries. We identify critical aspects for which no obvious solution exists and aspects where advanced control engineering can help, like piezo non‐linearities, the acceleration limit and the challenging technical requirements for the preamplifiers that are needed for measuring a tunneling current. Finally, we provide an overview of a number of new directions that are being pursued to solve the problems currently encountered in scanning probe technology. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Rapid AFM imaging of large soft samples in liquid with small forces
Authors: Tien Szuchi , Devasia Santosh
Published: April 2009

This article addresses the reduction of the tip‐sample force during rapid Atomic Force Microscope (AFM) imaging of large soft samples in liquid medium. Maintaining a small tip‐sample force is critical to avoid sample damage, especially when imaging soft biological samples or polymers. The tip‐sample force can be reduced if the AFM‐probe can be positioned to follow the sample topography as it is scanned over the surface. However, precision positioning over the sample topography has been challenging when imaging relatively large areas in soft samples. A zoom‐out/zoom‐in iterative method is proposed to achieve the precision positioning needed to maintain small tip‐sample forces during rapid AFM imaging. The method is used to demonstrate rapid imaging of soft hydrogel samples. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
A comparison of control architectures for atomic force microscopes
Authors: Butterworth J. A. , Pao L. Y. , Abramovitch D. Y.
Published: April 2009

We evaluate the performance of two control architectures applied to atomic force microscopes (AFM). Feedback‐only control is a natural solution and has been applied widely. Expanding on that, combining feedback controllers with plant‐injection feedforward filters has been shown to greatly improve tracking performance in AFMs. Alternatively, performance can also be improved by the use of a closed‐loop‐injection feedforward filter applied to the reference input before it enters the feedback loop. In this paper, we compare the plant‐injection architecture with the closed‐loop‐injection architecture when used in controlling AFMs. In particular, we provide experimental results demonstrating the closed‐loop‐injection architecture yields better tracking performance of a raster scan. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Semi‐automatic tuning of PID gains for atomic force microscopes
Authors: Abramovitch Daniel Y. , Hoen Storrs , Workman Richard
Published: April 2009

The control of a typical commercial Atomic Force Microscope (AFM) is through some variant on a Proportional, Integral, Derivative (PID) controller. Typically, the gains are hand tuned so as to keep the bandwidth of the system far below the first resonant frequency of the actuator. This paper shows a straightforward method of selecting PID gains from the actuator model so as to allow considerably higher bandwidths. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Force/motion sliding mode control of three typical mechanisms
Authors: Fung Rong‐Fong , Chang Chin‐Fu
Published: April 2009

This paper proposes a sliding mode control (SMC) algorithm for trajectory tracking of the slider‐crank mechanism, quick‐return mechanism, and toggle mechanism. First, the dynamic models suitable for the controls of both the motion and constrained force are derived using Hamilton's principle, the Lagrange multiplier, and implicit function theory. Second, the SMC is designed to ensure the input torques can achieve trajectory tracking on the constrained surfaces with specific constraint forces. Finally, the developed method is successfully verified for effectiveness of the force/motion controls for these three typical mechanisms from the results of simulation. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Vermeidung von Schäden an Schlitzrinnen
Authors: Breitenbücher Rolf , Sievering Christoph
Published: April 2009

In den letzten Jahren wurden auf mehreren Flughäfen im Bereich großer Verkehrsflächen Risse in Betonschlitzrinnen, die dort zur Entwässerung unabdingbar sind, festgestellt. Um die maßgeblichen Einflüsse für diese Rissbildungen zu analysieren, wurden sowohl Laboruntersuchungen als auch Berechnungen zu den Spannungsverhältnissen in den Raumfugen und den Schlitzrinnen selbst durchgeführt. Dabei lag das Hauptaugenmerk der Studien auf der Steifigkeit der Fugenfüllstoffe. Werden die an die Schlitzrinnen angrenzenden Verkehrsflächen in den Wintermonaten bei niedrigen Umgebungstemperaturen betoniert, dehnen diese sich in darauffolgenden Sommerperioden infolge der jahreszeitlich bedingten Temperaturerhöhung aus, wobei die Verformungen des freien Betonrands ohne weiteres 5 bis 10 mm betragen können. Diese Dehnungen sollen in der Raumfuge möglichst zwängungsfrei aufgenommen werden. Kann dies nicht sichergestellt werden, wirken seitliche Flächenpressungen auf die Seitenwände der Schlitzrinnen ein, die maßgeblich von der Steifigkeit des Füllmaterials abhängig sind. In einschlägigen Laboruntersuchungen wurden die jeweiligen Spannungs‐Dehnungsbeziehungen für verschiedene Fugenfüllstoffe bestimmt. Dabei zeigten die üblicherweise verwendeten bituminierten Weichfaserplatten eine vergleichsweise hohe Steifigkeit. In der Folge können daraus hohe Beanspruchungen in den Schlitzrinnen generiert werden, die die Rissbildung erklären.
Study of the interactions between a proline‐rich protein and a flavan‐3‐ol by NMR: Residual structures in the natively unfolded protein provides anchorage points for the ligands
Authors: Pascal Christine , Paté Franck , Cheynier Véronique , Delsuc Marc‐André
Published: April 2009

Astringency is one of the major organoleptic properties of food and beverages that are made from plants, such as tea, chocolate, beer, or red wine. This sensation is thought to be due to interactions between tannins and salivary proline‐rich proteins, which are natively unfolded proteins. A human salivary proline‐rich protein, namely IB‐5, was produced by the recombinant method. Its interactions with a model tannin, epigallocatechin gallate (EGCG), the major flavan‐3‐ol in green tea, were studied here. Circular dichroism experiments showed that IB‐5 presents residual structures (PPII helices) when the ionic strength is close to that in saliva. In the presence of these residual structures, IB‐5 undergoes an increase in structural content upon binding to EGCG. NMR data corroborated the presence of preformed structural elements within the protein prior to binding and a partial assignment was proposed, showing partial structuration. TOCSY experiments showed that amino acids that are involved in PPII helices are more likely to interact with EGCG than those in random coil regions, as if they were anchorage points for the ligand. The signal from IB‐5 in the DOSY NMR spectrum revealed an increase in polydispersity upon addition of EGCG while the mean hydrodynamic radius remained unchanged. This strongly suggests the formation of IB‐5/EGCG aggregates. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 745–756, 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
Microfluidic ARray Synthesizer (MArS) for rapid preparation and hybridization of custom DNA microarray
Authors: Cheng Ji‐Yen , Chen Huai‐Yi
Published: April 2009

The purpose of this work is to demonstrate a simple method that integrates custom DNA array synthesis and hybridization in a microfluidic channel. Commercial DLP projectors and a classical oligonucleotide synthesizer were integrated with a microfluidic chamber and constitute a Microfluidic ARray Synthesizer (MArS). Utilizing the benefit of microfluidics, the MArS produces two custom oligonucleotide arrays with reagent consumption for one array. The quality of the two arrays was examined by hybridization and shown to be almost identical. Post‐synthesis deprotection of the array and hybridization performed in the same microfluidic chamber reduced overall DNA assay time by two orders. In addition, mismatch discrimination was enhanced using the microfluidic chamber. In summary, a simple method to build a custom array synthesizer is demonstrated and its performance is examined. Biotechnol. Bioeng. 2009; 104: 400–407 © 2009 Wiley Periodicals, Inc.
Windows of operation for bioreactor design for the controlled formation of tissue‐engineered arteries
Authors: Gerontas Spyridon , Farid Suzanne S. , Hoare Michael
Published: April 2009

The availability of large numbers of units of artificial arteries would offer significant benefits to the clinical management of bypass surgery. Tissue engineering offers the potential of providing vessels that can mimic the morphology, function, and physiological environment of native vessels. Ideally this would involve culturing stem cells in vitro within a biodegradable tubular scaffold so as to construct tissue for implantation. Essential to establishing a robust process for the production of tissue‐engineered arteries is the understanding of the impact of changes in the operating conditions and bioreactor design on the construct formation. In this article, models of transport phenomena were developed to predict the critical flow rates and mass transfer requirements of a prototype bioreactor for the formation of tissue‐engineered arteries. The impact of the cell concentration, tube geometry, oxygen effective diffusivity in alginate, substrate and metabolite concentration levels, feed rate, and recycle rate on the design of the bioreactor was visualized using windows of operation and contour plots. The result of this analysis determined the best configuration of the bioreactor that meets the cellular transport requirements as well as being reliable in performance while seeking to reduce the amount of nutrients to be used. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Preparation and recycling of aqueous two‐phase systems with pH‐sensitive amphiphilic terpolymer PADB
Authors: Biao Ning , Junfen Wan , Xuejun Cao
Published: April 2009

In this study, a novel pH‐sensitive terpolymer PADB was synthesized by random terpolymerization of 2‐(dimethylamino) ethyl methacrylate, acrylic acid, and butyl methacrylate. The terpolymer PADB could form aqueous two‐phase systems (ATPS) with a light‐sensitive terpolymer PNBC, which was synthesized in our laboratory, using n‐isopropylacrylamide, n‐butyl acrylate, chlorophyllin sodium copper salt as monomers. More than 97% of the PADB terpolymer could be recovered by adjusting the pH to isoelectric point (PI) 4.1. The terpolymer PNBC could be recovered by using light radiation at 488 nm, with recovery ratio of 98%. BSA and lysozyme were partitioned in the PNBC–PADB ATPS to examine this new system. It was found that the partition coefficient of BSA and lysozyme could reach 4.46 and 0.49 in the systems, respectively. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Multiple three‐dimensional mammalian cell aggregates formed away from solid substrata in ultrasound standing waves
Authors: Kuznetsova Larisa A. , Bazou Despina , Edwards Gareth O. , Coakley W. Terence
Published: April 2009

Single and multiple three‐dimensional cell aggregates of human red blood cells (RBCs) and HepG2 cells were formed rapidly in low mega‐Hertz ultrasound standing wave fields of different geometries. A single discoid aggregate was formed in a half‐wavelength pathlength resonator at a cell concentration sufficient to produce a 3D structure. Multiple cell aggregates were formed on the axis of a cylindrical resonator with a plane transducer (discoid aggregates); in a resonator with a tubular transducer and in the cross‐fields of plane and tubular transducers and two plane orthogonal transducers (all cylindrical aggregates). Mechanically strong RBC aggregates were obtained by crosslinking with wheat germ agglutinin (WGA, a lectin). Scanning electron microscopy showed aggregate surface porous structures when RBCs were mixed with WGA before sonication and tighter packing when ultrasonically preformed aggregates were subsequently exposed to a flow containing WGA. HepG2 cell aggregates showed strong accumulation of F‐actin at sites of cell–cell contact consistent with increased mechanical stability. The aggregates had a porous surface, and yet confocal microscopy revealed a tight packing of cells in the aggregate's inner core. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
A Chemical Approach to Immunoprotein Engineering: Chemoselective Functionalization of Thioester Proteins in Their Native State
Authors: Cole Michael A. , Tully Sarah E. , Dodds Alister W. , Arnold James N. , Boldt Grant E. , Sim Robert B. , Offer John , Wentworth Paul
Published: April 2009

Less than 6 feet under: Serum proteins C3, C4, and α2M each contain a thioester domain buried within a hydrophobic pocket, which is thought to shield the labile thioester from hydrolysis. Herein, we make use of the inherent reactivity of the hydrazide for thioester moieties to chemoselectively label these crucial serum regulators in their native conformation; this demonstrates that access to the thioester site is much greater than previously supposed.

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Degradation of BTEX in Aqueous Solution by Hydrodynamic Cavitation
Authors: Braeutigam P. , Wu Z.‐L. , Stark A. , Ondruschka B.
Published: April 2009

A self‐made low‐pressure device (up to 100 psi) for hydrodynamic cavitation was tested with the reaction of BTEX (benzene, toluene, ethylbenzene, and xylenes) in water. Experimental parameters, such as inlet pressure, solution temperature, and concentration of the chosen substrates, as well as the effect of different restrictions were investigated. The energy efficiency of the process was measured in comparison to two acoustic cavitation systems (24 and 850 kHz). The products of the BTEX degradation were identified and a pyrolytic degradation pathway is concluded.
Metal‐Mediated [2+3] Cycloaddition of Nitrones to Palladium‐Bound Isonitriles
Authors: Luzyanin Konstantin V. , Tskhovrebov Alexander G. , Guedes da Silva M. Fátima C. , Haukka Matti , Pombeiro Armando J. L. , Kukushkin Vadim Yu.
Published: April 2009

[2+3] Cycloadditions! The metal‐mediated [2+3] cycloaddition of acyclic [−O+N(R2)(H)R3] and nonaromatic cyclic nitrones [−O+NaCHCH2CH2CbMe2(NaCb)] to palladium‐bound isonitriles cis‐[PdCl2(CNR)2] proceeds under mild conditions to furnish novel heterocyclic carbene complexes, which then undergo NO bond rupture to give imino complexes and free isocyanates (see scheme).

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The reactions between equimolar amounts of cis‐[PdCl2(CNR)2] (R=cyclohexyl (Cy) 1, tBu 2, 2,6‐Me2C6H3 (Xyl) 3) and the acyclic nitrones O+N(R2)C(H)R3 (R2=Me 5, R2=CH2Ph 6, R3=4‐MeC6H4) proceeded in C6H6 at 5 °C for around 4 h and then the reaction systems were maintained at 20–25 °C for 20 h to provide the carbene complexes [PdCl2{C(ONR2CcHR3)=NdR}(CNR)(CcNd)] (8–13) in good yields (54–70 %). The latter species originated from the previously unreported metal‐mediated [2+3] cycloaddition of nitrones to coordinated isonitriles. For the reactions of cis‐[PdCl2(CNR)2] (1–3) and 5 or 6 performed in C6H6 at 20–25 °C, the selectivity of the cycloaddition was lost, and the reactions gave mixtures of 8–13 and the complexes [PdCl2{N(R2)CHR3}(CNR)] (14–19, ca. 75 %) derived from intramolecular deoxygenation of the nitrones. The reactions of equimolar amounts of cis‐[PdCl2(CNR)2] (1–3 and R=4‐MeOC6H4 4) and the nonaromatic cyclic nitrone −O+NaCHCH2CH2CbMe2(NaCb) (7) in CHCl3 at 5 °C for around 2 h led to the carbene species [PdCl2{C(ONaCMe2CH2CH2CbH)=NeR}(CNR)(NaCb)(CbNe)] (21–24), isolated in yields of 78–92 %. When the reactions of cis‐[PdCl2(CNR)2] (1–4) and 7 (1:1 molar ratio) were performed in CHCl3 at 20–25 °C for around 1 h, the carbenes 21–24 and the complexes [PdCl2{NfCMe2CH2CH2CgH}(CNR)(NfCg)] (25–28, ca. 35 %), derived from the deoxygenation of 7, were identified by ESI+‐MS and 1H NMR analysis (after redissolution in CDCl3). The reactions of cis‐[PdCl2(CNR)2] (1–4) and 7 (1:2 molar ratio) in CHCl3 at 5 °C furnished mixtures of [PdCl2{C(ONaCMe2CH2CH2CbH)NeR}(NfCMe2CH2CH2CgH)(NaCb)(CbNe)(NfCg)] (29–32; ca. 25–30 %), 25–28 (ca. 10–15 %), and [PdCl2(ONaCMe2CH2CH2CbH)2(NaCb)]. The same reactions at room temperature afforded the complex [PdCl2(NfCMe2CH2CH2CgH)2(NfCg)] (33; ca. 20 %) in a mixture with 29–32 (ca. 5–10 %) and 25–28.
ChemInform Abstract: The Hydrolysis Behavior of Mg2Ni and Mg2NiH4 in Water or a 6 M KOH Solution and Its Application to Ni Nanoparticles Synthesis.
Authors: Wang Huabin , Han Lihong , Hu Henry , Northwood Derek O.
Published: April 2009

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ChemInform Abstract: Synthesis and Crystal Structure of the First Thallium Hydrous Nesosilicate Tl4SiO4·0.5H2O.
Authors: Britvin Sergey N. , Siidra Oleg I. , Krivovichev Sergey V. , Depmeier Wulf
Published: April 2009

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ChemInform Abstract: A New Transition Metal Tetracyanidoborate: Synthesis, Structure and Properties of Co[B(CN)4]2·2H2O.
Authors: Nitschke Christian , Koeckerling Martin
Published: April 2009

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ChemInform Abstract: Structural Transformation from Trinuclear Linear to Tetranuclear Cubane Heterobimetallic Selenium Compounds. Structure and Optical Linearities of [Et4N]2[(μ‐WSe4)(CuCl)2].
Authors: Liu Shu‐Lei , Duan Taike , Zhang Qian‐Feng , Leung Wa‐Hung
Published: April 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Highly Enantioselective Synthesis of γ‐Nitro Heteroaromatic Ketones in a Doubly Stereocontrolled Manner Catalyzed by Bifunctional Thiourea Catalysts Based on Dehydroabietic Amine: A Doubly Stereocontrolled Approach to Pyrrolidine Carboxylic Acids.
Authors: Jiang Xianxing , Zhang Yifu , Chan Albert S. C. , Wang Rui
Published: April 2009

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ChemInform Abstract: Mild Stereoselective Hydrohalogenation Leading to (Z)‐Halopropenamides at Room Temperature.
Authors: Feray Laurence , Perfetti Patricia , Bertrand Michele P.
Published: April 2009

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ChemInform Abstract: Rapid 1,4‐Alkynylation of Acyclic Enones Using K[F3BCCR].
Authors: Bertolini Ferruccio , Woodward Simon
Published: April 2009

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ChemInform Abstract: A Very Simple Copper‐Catalyzed Synthesis of Anilines by Employing Aqueous Ammonia.
Authors: Xia Ning , Taillefer Marc
Published: April 2009

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ChemInform Abstract: Asymmetric Claisen Rearrangements on Chiral Vinyl Sulfoxides.
Authors: Fernandez de la Pradilla Roberto , Montero Carlos , Tortosa Mariola , Viso Alma
Published: April 2009

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ChemInform Abstract: m‐Terphenyl Anchored Palladium Diphosphinite PCP‐Pincer Complexes that Promote the Suzuki—Miyaura Reaction under Mild Conditions.
Authors: Lipke Mark C. , Woloszynek Robert A. , Ma Liqing , Protasiewicz John D.
Published: April 2009

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ChemInform Abstract: An Asymmetric, SmI2‐Mediated Approach to γ‐Butyrolactones Using a New, Fluorous‐Tagged Auxiliary.
Authors: Vogel Johannes C. , Butler Rebecca , Procter David J.
Published: April 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis of 4‐Acetoxyindoles and Related Derivatives by Means of Air Oxidation of 4‐Oxo‐4,5,6,7‐tetrahydroindoles Obtained from Nitroalkenes and Cyclohexane‐1,3‐diones.
Authors: Arai Masaki , Miyauchi Yayoi , Miyahara Tadashi , Ishikawa Teruhiko , Saito Seiki
Published: April 2009

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ChemInform Abstract: Synthesis of Derivatives of Pyrazole with Chiral Substituents at the Nitrogen Atom.
Authors: Kurkin A. V. , Utkina A. A. , Yurovskaya M. A.
Published: April 2009

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ChemInform Abstract: Fragment‐Based Discovery of JAK‐2 Inhibitors.
Authors: Antonysamy Stephen , Hirst Gavin , Park Frances , Sprengeler Paul , Stappenbeck Frank , Steensma Ruo , Wilson Mark , Wong Melissa
Published: April 2009

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ChemInform Abstract: Synthesis and Antimicrobial Activity of Some Novel 2‐[4‐(Substituted Piperazin‐/Piperidin‐1‐ylcarbonyl)phenyl]‐1H‐benzimidazole Derivatives.
Authors: Kus Canan , Soezuedoenmez Fatma , Altanlar Nurten
Published: April 2009

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ChemInform Abstract: Condensation of γ‐Bromodypnone with Thiocarbamides: Synthesis of 4,4‐Disubstituted 4,5‐Dihydro‐1,3‐thiazol‐2‐amines and Thiazolidin‐2‐ones.
Authors: Potikha L. M. , Turov A. V. , Kovtunenko V. A.
Published: April 2009

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ChemInform Abstract: An Efficient One‐Pot Three‐Component Reaction to Produce 1,4‐Disubstituted‐1,2,3‐triazoles Catalyzed by a Dicopper‐Substituted Silicotungstate.
Authors: Yamaguchi Kazuya , Kotani Miyuki , Kamata Keigo , Mizuno Noritaka
Published: April 2009

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ChemInform Abstract: Copper(I) Iodide Catalyzed Domino Knoevenagel Hetero‐Diels—Alder Reaction of Terminal Acetylenes: Synthesis of Pyrano[2,3‐c]pyrazoles.
Authors: Khoshkolgh Malihe Javan , Balalaie Saeed , Bijanzadeh Hamid Reza , Gross Juergen H.
Published: April 2009

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ChemInform Abstract: Silica Sulfuric Acid: A Simple, Efficient, and Reusable Heterogeneous Catalyst for the One‐Pot Synthesis of Aryl‐14H‐dibenzo[a,j]xanthenes under Conventional Heating and Solvent‐Free Conditions.
Authors: Hunnur Raveendra K. , Sunilkumar B. , Kumar P. S. , Srinivasulu N. , Udupi R. H. , Hima bindu V.
Published: April 2009

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ChemInform Abstract: A Novel Three‐Component Reaction Toward Dihydrooxazolopyridines.
Authors: Scheffelaar Rachel , Paravidino Monica , Muilwijk Daan , Lutz Martin , Spek Anthony L. , de Kanter Frans J. J. , Orru Romano V. A. , Ruijter Eelco
Published: April 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.