bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prospective head‐movement correction for high‐resolution MRI using an in‐bore optical tracking system
Authors: Qin Lei , van Gelderen Peter , Derbyshire John Andrew , Jin Fenghua , Lee Jongho , de Zwart Jacco A. , Tao Yang , Duyn Jeff H. 
Published: June 2009

AbstractIn MRI of the human brain, subject motion is a major cause of magnetic resonance image quality degradation. To compensate for the effects of head motion during data acquisition, an in‐bore optical motion tracking system is proposed. The system comprises two MR‐compatible infrared cameras that are fixed on a holder right above and in front of the head coil. The resulting close proximity of the cameras to the object allows precise tracking of its movement. During image acquisition, the MRI scanner uses this tracking information to prospectively compensate for head motion by adjusting the gradient field direction and radio frequency (RF) phases and frequencies. Experiments performed on subjects demonstrate robust system performance with translation and rotation accuracies of 0.1 mm and 0.15°, respectively. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
A new investigation of the extended Krylov subspace method for matrix function evaluations
Authors: Knizhnerman L. , Simoncini V. 
Published: June 2009

AbstractFor large square matrices A and functions f, the numerical approximation of the action of f(A) to a vector v has received considerable attention in the last two decades. In this paper we investigate theextended Krylov subspace method, a technique that was recently proposed to approximate f(A)v for A symmetric. We provide a new theoretical analysis of the method, which improves the original result for A symmetric, and gives a new estimate for A nonsymmetric. Numerical experiments confirm that the new error estimates correctly capture the linear asymptotic convergence rate of the approximation. By using recent algorithmic improvements, we also show that the method is computationally competitive with respect to other enhancement techniques. Copyright © 2009 John Wiley & Sons, Ltd.
Topology optimization of muffler internal partitions for improving acoustical attenuation performance
Authors: Lee Jin Woo , Kim Yoon Young 
Published: June 2009

AbstractThe internal partition configuration of an expansion chamber muffler affects significantly its acoustical transmission characteristics, but the use of systematic optimization methods to muffler design problems is rare. The main objective of this research is to maximize the transmission loss at target frequencies by optimizing partition layouts inside a muffler chamber by formulating an acoustical topology optimization problem. The selected target frequencies include the deep frequencies of a nominal muffler in order to see the critical effects of partition configurations on the acoustical transmission characteristics. The effects of partition volume constraint ratios are also investigated and physics behind the optimized layouts is investigated. Numerical results show that mufflers with optimized partition layouts outperform nominal mufflers considerably, but the shapes and locations of the optimized partitions should be much different from those of conventional partitions. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis and implementation issues for the numerical approximation of parabolic equations with random coefficients
Authors: Nobile F. , Tempone Raul 
Published: June 2009

AbstractWe consider the problem of numerically approximating statistical moments of the solution of a time‐dependent linear parabolic partial differential equation (PDE), whose coefficients and/or forcing terms are spatially correlated random fields. The stochastic coefficients of the PDE are approximated by truncated Karhunen–Loève expansions driven by a finite number of uncorrelated random variables. After approximating the stochastic coefficients, the original stochastic PDE turns into a new deterministic parametric PDE of the same type, the dimension of the parameter set being equal to the number of random variables introduced.After proving that the solution of the parametric PDE problem is analytic with respect to the parameters, we consider global polynomial approximations based on tensor product, total degree or sparse polynomial spaces and constructed by either a Stochastic Galerkin or a Stochastic Collocation approach. We derive convergence rates for the different cases and present numerical results that show how these approaches are a valid alternative to the more traditional Monte Carlo Method for this class of problems. Copyright © 2009 John Wiley & Sons, Ltd.
Using data in legacy fundraising: a practical approach
Authors: Magson Nigel , Routley Claire 
Published: June 2009

Abstract

Legacies provide a major source of income to charities, and their importance is only likely to increase with the passing on of the baby‐boomer generation. Legacy fundraising is a long‐term process, based on developing relationships with donors over time. Data have a key role to play in the development of these relationships, allowing legacy fundraisers to measure and track their donors, and to contribute to the development of effective fundraising strategies. This paper discusses the effective collection and use of data in legacy fundraising, from consolidating data, to analysing the results and building legacy targeting models. The authors discuss how these principles have been applied in UK‐based charity, Help the Aged, in conjunction with their Data Agency, Tangible Data (formerly Talking Numbers) and to give practical advice on how they may be implemented in other organisations.

Copyright © 2009 John Wiley & Sons, Ltd.
Time‐optimal control of automobile test drives with gear shifts
Authors: Kirches Christian , Sager Sebastian , Bock Hans Georg , Schlöder Johannes P. 
Published: June 2009

AbstractWe present a numerical method and results for a recently published benchmark problem (Optim. Contr. Appl. Met. 2005; 26:1–18; Optim. Contr. Appl. Met. 2006; 27(3):169–182) in mixed‐integer optimal control. The problem has its origin in automobile test‐driving and involves discrete controls for the choice of gears. Our approach is based on a convexification and relaxation of the integer controls constraint. Using the direct multiple shooting method we solve the reformulated benchmark problem for two cases: (a) As proposed in (Optim. Contr. Appl. Met. 2005; 26:1–18), for a fixed, equidistant control discretization grid and (b) As formulated in (Optim. Contr. Appl. Met. 2006; 27(3):169–182), taking into account free switching times. For the first case, we reproduce the results obtained in (Optim. Contr. Appl. Met. 2005; 26:1–18) with a speed‐up of several orders of magnitude compared with the Branch&Bound approach applied there (taking into account precision and the different computing environments). For the second case we optimize the switching times and propose to use an initialization based on the solution of (a). Compared with (Optim. Contr. Appl. Met. 2006; 27(3):169–182) we were able to reduce the overall computing time considerably, applying our algorithm. We give theoretical evidence on why our convex reformulation is highly beneficial in the case of time‐optimal mixed‐integer control problems as the chosen benchmark problem basically is (neglecting a small regularization term). Copyright © 2009 John Wiley & Sons, Ltd.
Preparation of albumin—PAA nanocapsules and their controlled release behavior for drugs
Authors: Wang Rong‐Min , Li Gang , Zhang Hui‐Fang , He Yu‐Feng , He Nai‐Pu , Lei Ziqiang 
Published: June 2009

AbstractNew kinds of narrowly distributed protein‐based nanoparticles, bovine serum albumin‐Poly (acrylic acid) (BSA/PAA) nanospheres, and nanocapsules were prepared via in situ polymerization, swelling, and re‐aggregation. The structure and morphology of the nanospheres were characterized by UV‐Vis, FT‐IR, DLS, and TEM. The stability of the BSA/PAA nanospheres and nanocapsules was increased when their skeletons were fixed by cross‐linked agents. The nanospheres carried a positive charge and their size was about 80–110 nm. The protein‐based nanocapsules were stimuli‐responsive with pH value and their hydrodynamic diameter varied from 70 to 230 nm with changes of pH. In vitro release experiments of Rhodamine B and Doxorubicin hydrochloride showed that these biopolymer nanoparticles provided a controlled release of the entrapped drugs for 300 hr. Copyright © 2009 John Wiley & Sons, Ltd.
Silver sulfide as a staining agent for scanning electron microscopy of nylon 6/MXD6 blends
Authors: Magniez Kevin , Fox Bronwyn L , Looney Mark G 
Published: June 2009

AbstractBACKGROUND: In transmission and scanning electron microscopy imaging, the ability to obtain sufficient contrast between the components of a blend when they are both of a similar chemical structure still remains problematic. This paper investigates the domain morphology of a polymer blend containing two polyamides, nylon 6 and the semi‐aromatic polyamide poly(m‐xylene adipamide) (MXD6), using scanning electron microscopy in backscattered electron imaging mode. The efficiency of three staining agents, ruthenium tetroxide, phosphotungstic acid and silver sulfide, in obtaining optimum phase contrast between the two polymers is discussed.RESULTS: The use of silver sulfide as a staining agent was found to be a fast and reliable approach which required basic sample preparation and provided excellent compositional contrast between the phases present in the nylon 6/MXD6 blends compared to the other staining agents.CONCLUSIONS: The technique described in this paper is believed to be a novel and versatile method that has the potential to further improve the ability to study complex polymer blends where one polymer contains an aromatic ring. Copyright © 2009 Society of Chemical Industry
Synthesis of Cibacron Blue F3GA‐coupled magnetic PMMA nanospheres and their use for protein affinity separation
Authors: Qu Feng , Guan Yueping , Ma Zhiya , Zhang Qiang 
Published: June 2009

AbstractBACKGROUND: New magnetic carrier separation technologies, capable of treating dilute solutions in large‐scale processes, even in the presence of biological debris, are necessary for the future development of biotechnology. Non‐porous magnetic carriers are more resistant to fouling, show better mass transfer and have lower non‐specific adsorption than porous carriers. Nanosized magnetic carriers have a surface area comparable to that of typical macroporous resins, and therefore their application has advantages.RESULTS: Magnetic poly(methyl methacrylate) (PMMA) nanospheres with an average diameter of 76 nm and narrow size distribution were prepared by a facile mini‐emulsion polymerization. After surface modification with poly(ethylene glycol), Cibacron Blue F3GA (CB) was coupled to the magnetic PMMA nanospheres to form dye ligand‐attached magnetic adsorbents for bovine serum albumin (BSA) adsorption. The CB‐coupled magnetic PMMA nanospheres showed very high adsorption capacity (121.98 mg g−1) and little non‐specific adsorption for BSA. The adsorbed protein could be easily desorbed using high ionic strength solution.CONCLUSION: The CB‐coupled magnetic PMMA nanospheres showed a high BSA adsorption capacity, low non‐specific adsorption and fast adsorption kinetics in comparison with other dye‐affinity adsorbents. These characteristics indicate that these magnetic PMMA nanospheres have great potential for protein affinity separation and purification. Copyright © 2009 Society of Chemical Industry
Anomalous rheological behavior of poly(1‐vinyl‐2‐pyrrolidone) and CuCl2 in solution and their interactions in solid composites
Authors: Hao Chaowei , Zhao Ying , Dong Xia , Zhou Yong , Xu Yizhuang , Wang Dujin , Lai Guoqiao , Jiang Jianxiong 
Published: June 2009

AbstractBACKGROUND: The aggregation structure of polymers in solution is an important aspect of their behavior. The interactions between metal ions and water‐soluble polymers have a significant influence on the conformation behavior of biological macromolecules, and on the ionic selectivity of cells, etc.RESULTS: The rheological behavior of poly(1‐vinyl‐2‐pyrrolidone) (PVP) and CuCl2 dispersed in N,N‐dimethylformamide was investigated using rheological techniques. Concentrated solutions containing CuCl2 exhibited a rheological behavior different from those containing other metal chlorides (LiCl, CaCl2 and CoCl2). This indicated that the variation in the aggregation state of the PVP chains with concentration of CuCl2 was different from those of PVP solutions containing Li+, Ca2+ or Co2+ ions.CONCLUSION: The interactions between PVP and CuCl2 inhibit the crystallization of CuCl2 and induce the formation of microphase separation in the system. Copyright © 2009 Society of Chemical Industry
Synthesis of poly(fluorinated styrene)‐block‐poly(ethylene oxide) amphiphilic copolymers via atom transfer radical polymerization: potential application as paper coating materials
Authors: Ibrahim Khalid A , Al‐Muhtaseb Ala'a H , Seppälä Jukka 
Published: June 2009

AbstractBACKGROUND: The surface of a substrate which comprises a fibrous material is brought into contact with a type of amphiphilic block copolymer which comprises hydrophilic/hydrophobic polymeric blocks. These amphiphilic copolymers have been synthesized by atom transfer radical polymerization (ATRP) technique. The atom transfer radical polymerization of poly(2,3,4,5,6‐pentafluorostyrene)‐block‐poly(ethylene oxide) (PFS‐b‐PEO) copolymers (di‐ and triblock structures) with various ranges of PEO molecular weights was initiated by a PEO chloro‐telechelic macroinitiator. The polymerization, carried out in bulk and catalysed by copper(I) chloride in the presence of 2,2′‐bipyridine ligand, led to A–B–A amphiphilic triblock and A–B amphiphilic diblock structures.RESULTS: With most of the macroinitiators, the living nature of the polymerizations led to block copolymers with narrow molecular weight distributions (1.09 < Mw/Mn < 1.33) and well‐controlled molecular structures. These block copolymers turned out to be water‐soluble through adjustment of the PEO block content (>90 wt%). Of all the block copolymers synthesized, PFS‐b‐PEO(10k)‐b‐PFS containing 10 wt% PFS was found to retard water absorption considerably.CONCLUSION: The printability of paper treated with the copolymers was evaluated with contact angle measurements and felt pen tests. The adsorption of such copolymers at the solid/liquid interface is relevant to the wetting and spreading of liquids on hydrophobic/hydrophilic surfaces. Copyright © 2009 Society of Chemical Industry
Synthesis and characterization of a series of diverse poly(2‐oxazoline)s
Authors: Kempe Kristian , Lobert Matthias , Hoogenboom Richard , Schubert Ulrich S. 
Published: June 2009

AbstractThis article describes the synthesis and characterization of a variety of new poly(2‐oxazoline)s. With regard to functional polymers, 2‐oxazolines represent an interesting class of monomers because of the easy variation of the substituent in 2‐position. Starting from the corresponding nitriles, different 2‐oxazolines were obtained containing a diverse set of 2‐substituents, including thioether bonds (M11), trifluoromethyl groups (M8, M10), and alkyl‐ or aryl groups (M1–M7). The subsequent polymerization of the majority of these monomers proceeded in a living manner, which was demonstrated by linear first‐order kinetics, a linear increase of molar mass with conversion, and relatively narrow molar mass distributions. In addition, selected thermal and surface properties of the polymers were studied utilizing DSC and contact‐angle measurements to determine the effects of different 2‐substituents on the macroscopic properties. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3829–3838, 2009
Synthesis and characterization of hyperbranched polyesters from glycerol‐based AB2 monomer
Authors: Parzuchowski Pawel G. , Grabowska Martyna , Jaroch Michal , Kusznerczuk Monika 
Published: June 2009

AbstractThis article describes the synthesis of a new glycerol‐based AB2 type monomer—ethyl{3‐[2‐hydroxy‐1‐(hydroxymethyl)ethoxy]propyl}thioacetate (4) and its application for the preparation of hyperbranched polyesters. The polycondensation of 4 has been performed over a wide range of catalysts and reaction conditions leading to polymers containing solely primary hydroxyl groups. The polycondensation progress has been monitored by means of 1H NMR. The degree of branching of the polymers showed to be in the range of 0.5 ± 0.03. The obtained polyesters easily undergo hydrolysis or alcoholysis and may be of interest as recycled materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3860–3868, 2009
Synthesis and properties of nitrogen‐linked poly(2,7‐carbazole)s as hole‐transport material for organic light emitting diodes
Authors: Michinobu Tsuyoshi , Kumazawa Hiroe , Otsuki Eiji , Usui Hiroaki , Shigehara Kiyotaka 
Published: June 2009

AbstractA novel class of carbazole polymers, nitrogen‐linked poly(2,7‐carbazole)s, was synthesized by polycondensation between two bifunctional monomers using the palladium‐catalyzed amination reaction. The polymers were characterized by 1H NMR, Infrared, Gel permeation chromatography, and MALDI‐TOF MS and it was revealed that the combination of the monomer structures is important for producing high molecular weight polymers. Thermal analysis indicated a good thermal stability with high glass transition temperatures, e.g., 138 °C for the higher molecular weight polymer P2. To pursue the application possibilities of these polymers, their optical properties and energy levels were investigated by UV‐Vis absorption and fluorescence spectra as well as their electrochemical characteristics. Although the blue light emission was indeed observed for all polymers in solution, the quantum yields were very low and the solid films were not fluorescent. On the other hand, the HOMO levels of the polymers estimated from the onset potentials for the first oxidation in the solid thin films were relatively high in the range of −5.12 to −5.20 eV. Therefore, light emitting diodes employing these polymers as a hole‐transport layer and iridium(III) complex as a triplet emitter were fabricated. The device of the nitrogen‐linked poly(2,7‐carbazole) P3 with p,p′‐biphenyl spacer, which has a higher HOMO level and a higher molecular weight, showed a much better performance than the device of P2 with m‐phenylene spacer. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3880–3891, 2009
General description of the structure of branched polymers
Authors: Gray‐Weale Angus , Gilbert Robert G. 
Published: June 2009

AbstractA multidimensional distribution function is defined to describe the branching structure of branched homopolymers such as starch and polyacrylates. Averages of this function give distributions which can be measured using, for example, the number and weight distributions as a function of hydrodynamic volume from size‐exclusion chromatography and field‐flow fractionation, and two‐dimensional separation methods. This provides means to plot data to obtain physically meaningful quantities, and to test mechanistic postulates for the (bio)synthesis, of branched polymers. A simple enzyme‐kinetic model for a reduced form of this multidimensional distribution for starch biosynthesis is derived and solved. One application is to derive number distributions for the molecular weight distribution of debranched glycogen. Fitting this to experiment gives estimates of this ratio for two forms of glycogen. We propose that number distributions from size separation for starch (which, it is pointed out, are obtained directly from in‐line viscometric detection) have a simple and meaningful form when plotted as ln(number distribution) against Vhp, where Vh is hydrodynamic volume, and p a parameter of order unity determined from multiple‐detection size separation measurements. The new function is also used to propose a two‐dimensional experiment which can yield an unambiguous measurement of the amylose: amylopectin ratio in starch. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3914–3930, 2009
Thermal curing behavior of MWCNT modified vinyl ester‐polyester resin suspensions prepared with 3‐roll milling technique
Authors: Seyhan A. T. , de la Vega Alejandra , Tanoglu M. , Schulte K. 
Published: June 2009

AbstractThis study aims to investigate the curing behavior of a vinyl ester‐polyester resin suspensions containing 0.3 wt % of multiwalled carbon nanotubes with and without amine functional groups (MWCNTs and MWCNT‐NH2). For this purpose, various analytical techniques, including Differential Scanning Calorimetry (DSC), Fourier infrared spectroscopy (FTIR), Raman Spectroscopy, and Thermo Gravimetric Analyzer (TGA) were conducted. The resin suspensions with carbon nanotubes (CNTs) were prepared via 3‐roll milling technique. DSC measurements showed that resin suspensions containing CNTs exhibited higher heat of cure (Q), besides lower activation energy (Ea) when compared with neat resin. For the sake of simplicity of interpretation, FTIR investigations were performed on neat vinyl ester resin suspensions containing the same amount of CNTs as resin. As a result, the individual fractional conversion rates of styrene and vinyl ester were interestingly found to be altered dependent on MWCNTs and MWCNT‐NH2. The findings obtained from RS measurements of the cured samples are highly proportional to those obtained from FTIR measurements. TGA measurements revealed that CNT modified nanocomposites have higher activation energy of degradation (Ed) compared with the cured polymer. The findings obtained revealed that CNTs with and without amine functional groups alter overall thermal curing response of the surrounding matrix resin, which may probably impart distinctive characteristics to mechanical behavior of the corresponding nanocomposites achieved. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1511–1522, 2009
Deamidation of α‐synuclein
Authors: Robinson Noah E. , Robinson Matthew L. , Schulze Stephanie E. S. , Lai Bert T. , Gray Harry B. 
Published: June 2009

AbstractThe rates of deamidation of α‐synuclein and single Asn residues in 13 Asn‐sequence mutants have been measured for 5 × 10−5M protein in both the absence and presence of 10−2M sodium dodecyl sulfate (SDS). In the course of these experiments, 370 quantitative protein deamidation measurements were performed and 37 deamidation rates were determined by ion cyclotron resonance Fourier transform mass spectrometry, using an improved whole protein isotopic envelope method and a mass defect method with both enzymatic and collision‐induced fragmentation. The measured deamidation index of α‐synuclein was found to be 0.23 for an overall deamidation half‐time of 23 days, without or with SDS micelles, owing primarily to the deamidation of Asn(103) and Asn(122). Deamidation rates of 15 Asn residues in the wild‐type and mutant proteins were found to be primary sequence controlled without SDS. However, the presence of SDS micelles slowed the deamidation rates of nine N‐terminal region Asn residues, caused by the known three‐dimensional structures induced through protein binding to SDS micelles.