bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of molecularly imprinted polymer films on monodisperse macromolecular beads
Authors: Zheng Ximing , Tu Weiping , Fan Rongyu 
Published: April 2009

AbstractA 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

AbstractHigh‐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

AbstractThe 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

AbstractPolypropylene (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

AbstractThe 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

AbstractScanning 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

AbstractThis 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

AbstractWe 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

AbstractThe 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

AbstractThis 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

AbstractIn 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

AbstractAstringency 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

AbstractThe 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

AbstractThe 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

AbstractIn 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

AbstractSingle 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

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

AbstractA 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.