bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of ofloxacin and lomefloxacin in chicken muscle using molecularly imprinted solid‐phase extraction coupled with liquid chromatography
Authors: Qiao Jindong , Yan Hongyuan , Wang Hui , Lv Yunkai 
Published: August 2011

AbstractA new molecularly imprinted solid‐phase extraction (MISPE) procedure combined with liquid chromatography was developed for the simultaneous selective extraction and determination of ofloxacin (OFL) and lomefloxacin (LOM) in chicken muscle samples. The water‐compatible molecularly imprinted microspheres (MIMs) were synthesized by aqueous suspension polymerization using 2‐hydroxy‐3‐naphthoic acid and 1‐methylpiperazine as mimic templates. The MIMs applied as selective sorbents in SPE method showed high selectivity and affinity to OFL and LOM in complex biological matrices. Good linearity was obtained in a range of 0.025–2.0 μg/g, and the average recoveries of OFL and LOM at three spiked levels ranged from 94.4 to 96.9%, respectively, with the relative standard deviation ≤4.7%. The developed MISPE‐HPLC method was successfully applied to the isolation of OFL and LOM in chicken muscles, which demonstrated the potential ability of the novel MIMs for selective extraction of fluoroquinolones in biological samples.
Determination of bisphenol A with effective pretreatment medium using automated column‐switching HPLC with fluorescence detection
Authors: Tanigawa Tetsuya , Watabe Yoshiyuki , Kubo Takuya , Hosoya Ken 
Published: August 2011

AbstractA practical way for reducing contaminants, such as humic acids, and solving column‐clogging problem in environmental water analysis with liquid chromatography is proposed. Detection interference by contamination is one of the most important issues of the environmental analyses. Moreover, due to the recent smaller diameter and fine particle size of an analytical column for HPLC system, a column‐clogging problem is another practical difficulty as well. We found it possible to solve these problems by employing column‐switching HPLC, which consists of a pretreatment column containing surface‐modified polymer particles and flow changeover valves for cleaning the remaining matrices in the pretreatment column prior to analysis. This method was successfully applied to actual HPLC‐fluorescence detection of bisphenol A. Limit of detection (LOD) in real sample was <0.7 ng/L. Repeatability was around 1.4% and recovery was around 97% or more. A particular pressure increase was not observed in 150 repeated analyses of real river water samples.
Simultaneous determination nucleosides in marine organisms using ultrasound‐assisted extraction followed by hydrophilic interaction liquid chromatography–electrospray ionization time‐of‐flight mass spectrometry
Authors: Zhao Hengqiang , Chen Junhui , Shi Qian , Li Xin , Zhou Wenhui , Zhang Daolai , Zheng Li , Cao Wei , Wang Xiaoru , Sen‐Chun Lee Frank 
Published: August 2011

AbstractA new method has been developed based on ultrasound‐assisted extraction (UAE) followed by hydrophilic interaction chromatography (HILIC) and electrospray ionization time‐of‐flight mass spectrometry (ESI‐TOF/MS) for the simultaneous determination of 16 nucleosides and nucleobases in medicinal extracts of various marine organisms. The separation was achieved on a Venusil HILIC column (250×4.6 mm id, 5 μm) and gradient elution using a solution of acetonitrile and buffer (0.20% formic acid and 20 mmol/L ammonium acetate) as the mobile phase. Identification of the 16 target nucleosides and nucleobases was based on the retention time, UV spectra, and mass measurements of the protonated molecules ([M+H]+) and main fragment ions (ESI‐TOF/MS). In addition, non‐target compounds of 2′‐deoxyinosine and four other amino acids were also tentatively identified by ESI‐TOF/MS. The 16 target compounds were quantified by HILIC‐ESI‐TOF/MS under optimized mass conditions. All calibration curves showed good linearity (r2>0.9951). The recoveries were 84.72–124.10%, and the limits of detection of the 16 target compounds were 0.6–130.0 ng/mL. The developed method was applied to quantify the target compounds in 15 batches of various marine organisms. The method has potential applicability for the identification and determination of highly polar and low‐concentration active compounds in marine organisms.
Detection of lard in vegetable oils
Authors: Che Man Yaakob B. , Rohman Abdul 
Published: August 2011

AbstractThe presence of animal fats, in particular lard (pig fat), in any product is of real concern to some communities, especially Muslims and Jews, due to the religious prohibition of these commodities. This is especially so when lard is used as substitute for vegetable oils in foods or other consumer goods such as cosmetics and pharmaceuticals. Manufactures and producers alike should be sensitive towards the issues of unlawful material in these products as halal and kosher markets are expected to proliferate in the coming years. This article highlights some analytical techniques proposed to detect and to quantify lard in vegetable oils such as Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), chromatographic‐based techniques, and electronic nose (EN).
Effect of Candida antarctica Lipase B Immobilization on the Porous Structure of the Carrier
Authors: Miletić Nemanja , Vuković Zorica , Nastasović Aleksandra , Loos Katja 
Published: August 2011

AbstractA series of poly(GMA‐co‐EGDMA) resins with identical composition but varying particle sizes, pore radii, specific surface areas and specific volumes are studied to assess how Candida antarctica lipase B immobilization affects the porosity of the copolymer particles. Mercury porosimetry reveals a significant change in the average pore size (up to 6.1‐fold), the specific surface area (up to 3.2‐fold) and the specific volume (up to 2.1‐fold) of the epoxy resin. A similar behaviour is observed for glutaraldehyde‐modified epoxy resins. The influences of the resin porosity properties on the loading of Candida antarctica lipase B during immobilization and on the hydrolytic activity (hydrolysis of p‐nitrophenyl acetate) of the immobilized lipase are studied. magnified image
Functional and Highly Porous Scaffolds for Biomedical Applications
Authors: Tyson Therese , Målberg Sofia , Wåtz Veronica , Finne‐Wistrand Anna , Albertsson Ann‐Christine 
Published: August 2011

AbstractHighly porous functional scaffolds were obtained from linear and cross‐linked multifunctional poly(ε‐caprolactone) and poly(L‐lactide). The polymers were synthesized by ring‐opening polymerization of ε‐caprolactone and L‐lactide using poly(but‐2‐ene‐1,4‐diyl malonate) (PBM) as macroinitiator and stannous 2‐ethylhexanoate. The presence of a double bond in each repeating unit of PBM enabled cross‐linking of both scaffolds and films. Soft and flexible scaffolds were created from cross‐linked PBM. The mechanical properties of scaffolds and films were evaluated under cyclic conditions, with a focus on the compositions and molecular weights. It was obvious that PBM in the polymers and its cross‐linking ability resulted in tunable material characteristics, including an increased ability to recover after repeated loading. magnified image
Water‐Free Synthesis of Polyurethane Foams Using Highly Reactive Diisocyanates Derived from 5‐Hydroxymethylfurfural
Authors: Neumann Christopher N. D. , Bulach Winfried D. , Rehahn Matthias , Klein Roland 
Published: August 2011

AbstractThis paper reports on the synthesis of a new highly reactive diisocyanate monomer based on hydroxymethylfurfural. It further describes its catalyst‐free conversion to linear‐chain thermoplastic polyurethanes as well as to cross‐linked polyurethane foams. In addition, a novel strategy for the synthesis of polyurethane foams without the necessity of using water is developed. Nitrogen is utilized herein as blowing agent which is formed during Curtius rearrangement of a new furan based carboxylic azide into its corresponding diisocyanate.magnified image
Electro‐active Polymer Actuator Based on Sulfonated Polyimide with Highly Conductive Silver Electrodes Via Self‐metallization
Authors: Song Jiangxuan , Jeon Jin‐Han , Oh Il‐Kwon , Park K. C. 
Published: August 2011

AbstractWe report here a facile synthesis of high performance electro‐active polymer actuator based on a sulfonated polyimide with well‐defined silver electrodes via self‐metallization. The proposed method greatly reduces fabrication time and cost, and obviates a cation exchange process required in the fabrication of ionic polymer‐metal composite actuators. Also, the self‐metallized silver electrodes exhibit outstanding metal‐polymer adhesion with high conductivity, resulting in substantially larger tip displacements compared with Nafion‐based actuators. magnified image
High temporal resolution retrospective motion correction with radial parallel imaging
Authors: Lin Wei , Huang Feng , Duensing George R. , Reykowski Arne 
Published: August 2011

AbstractA method for motion correction in multicoil imaging applications, involving both data collection and reconstruction, is presented. A bit‐reversed radial acquisition scheme, in conjunction with a rapid self‐calibrated parallel imaging method, Generalized auto‐calibrating partial parallel acquisition (GRAPPA) operator for wider radial bands (GROWL), is used to achieve motion correction at a high temporal resolution. View‐by‐view in‐plane motion correction is achieved in 2D imaging, while 3D motion correction is achieved for every two consecutive slice‐encoding planes in 3D imaging. In the proposed technique, GROWL contributes in two aspects: First, a central k‐space circle/cylinder used as the motion‐free reference is generated from a small number of radial lines/planes; Second, undersampled k‐space regions resulting from rotation and inconsistent (e.g. intraview and nonrigid body) motion can be filled in. When compared with navigator‐based motion correction methods, the proposed method does not prolong scan time and can be applied to short‐TR sequences. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Comparison of measuring energy metabolism by different 31P‐magnetic resonance spectroscopy techniques in resting, ischemic, and exercising muscle
Authors: Schmid Albrecht I. , Schrauwen‐Hinderling Vera B. , Andreas Martin , Wolzt Michael , Moser Ewald , Roden Michael 
Published: August 2011

AbstractAlternate methods to quantify mitochondrial activity or function have been extensively used for studying insulin resistance and type 2 diabetes mellitus, namely saturation transfer and phosphocreatine (PCr) recovery. As these methods are in fact determining different parameters, this study aimed to compare saturation transfer results to PCr recovery measurements within the same group. Fifteen subjects underwent saturation transfer and ischemic exercise‐recovery experiments. PCr decrease during ischemia (Q), induced by cuff inflation, served as an additional measure of resting ATP (adenosine triphosphate) production. ATP synthetic rate (fATP) measured by saturation transfer (0.234 ± 0.043 mM/s) was greater than (Q = 0.0077 ± 0.0011 mM/s), but correlated well with Q (r = 0.63 P = 0.013). Parameters of PCr recovery correlated well with fATP (Qmax,lin: r = 0.71, P = 0.003, Qmax,ADP: r = 0.66, P = 0.007) and Q (Qmax,lin: r = 0.92, P = 0.000002, Qmax,ADP: r = 0.76, P = 0.001). In conclusion, although saturation transfer yields higher ATP synthetic rates than PCr decrease during ischemia, their significant correlation indicates that fATP can be used as a marker of mitochondrial activity. The finding that both Q and fATP correlate with PCr recovery kinetics suggests that skeletal muscle with greater maximal aerobic ATP synthetic rates is also metabolically more active at rest. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Whole body traveling wave magnetic resonance imaging at high field strength: Homogeneity, efficiency, and energy deposition as compared with traditional excitation mechanisms
Authors: Zhang Bei , Sodickson Daniel K. , Lattanzi Riccardo , Duan Qi , Stoeckel Bernd , Wiggins Graham C. 
Published: August 2011

AbstractIn 7 T traveling wave imaging, waveguide modes supported by the scanner radiofrequency shield are used to excite an MR signal in samples or tissue which may be several meters away from the antenna used to drive radiofrequency power into the system. To explore the potential merits of traveling wave excitation for whole‐body imaging at 7 T, we compare numerical simulations of traveling wave and TEM systems, and juxtapose full‐wave electrodynamic simulations using a human body model with in vivo human traveling wave imaging at multiple stations covering the entire body. The simulated and in vivo traveling wave results correspond well, with strong signal at the periphery of the body and weak signal deep in the torso. These numerical results also illustrate the complicated wave behavior that emerges when a body is present. The TEM resonator simulation allowed comparison of traveling wave excitation with standard quadrature excitation, showing that while the traveling wave B per unit drive voltage is much less than that of the TEM system, the square of the average B compared to peak specific absorption rate (SAR) values can be comparable in certain imaging planes. Both systems produce highly inhomogeneous excitation of MR signal in the torso, suggesting that B1 shimming or other parallel transmission methods are necessary for 7 T whole body imaging. Magn Reson Med 67:1183–1193, 2011. © 2011 Wiley‐Liss, Inc.
Spatially encoded phase‐contrast MRI—3D MRI movies of 1D and 2D structures at millisecond resolution
Authors: Merboldt Klaus‐Dietmar , Uecker Martin , Voit Dirk , Frahm Jens 
Published: August 2011

AbstractThis work demonstrates that the principles underlying phase‐contrast MRI may be used to encode spatial rather than flow information along a perpendicular dimension, if this dimension contains an MRI‐visible object at only one spatial location. In particular, the situation applies to 3D mapping of curved 2D structures which requires only two projection images with different spatial phase‐encoding gradients. These phase‐contrast gradients define the field of view and mean spin‐density positions of the object in the perpendicular dimension by respective phase differences. When combined with highly undersampled radial fast low angle shot (FLASH) and image reconstruction by regularized nonlinear inversion, spatial phase‐contrast MRI allows for dynamic 3D mapping of 2D structures in real time. First examples include 3D MRI movies of the acting human hand at a temporal resolution of 50 ms. With an even simpler technique, 3D maps of curved 1D structures may be obtained from only three acquisitions of a frequency‐encoded MRI signal with two perpendicular phase encodings. Here, 3D MRI movies of a rapidly rotating banana were obtained at 5 ms resolution or 200 frames per second. In conclusion, spatial phase‐contrast 3D MRI of 2D or 1D structures is respective two or four orders of magnitude faster than conventional 3D MRI. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Tailored excitation in 3D with spiral nonselective (SPINS) RF pulses
Authors: Malik Shaihan J. , Keihaninejad Shiva , Hammers Alexander , Hajnal Joseph V. 
Published: August 2011

AbstractBrain images acquired at 3T often display central brightening with spatially varying tissue contrast, caused by inhomogeneity in the transmit radiofrequency fields used for excitation. Tailored radiofrequency pulses can provide mitigation of radiofrequency field inhomogeneity, but previous designs have been unsuitable for 3D imaging in rapid pulse sequences. This article presents a nonselective pulse design based on a short (1 ms) 3D spiral k‐space trajectory that covers low spatial frequencies. The resulting excitations are optimized to produce a uniform excitation within a specified volume of interest covering the whole brain. B1 mapping and pulse calculation times were reduced by optimizing in only five slices within the brain. The method has been tested with both single and parallel transmission: in phantom experiments, normalized root‐mean‐square error in excitation was 0.022 for single and 0.020 for parallel transmission. The corresponding results in vivo were 0.066 and 0.055 respectively. A pilot brain imaging study using the proposed pulses for excitation within the Alzheimer's disease neuroimaging initiative magnetization prepared rapid gradient echo (MP‐RAGE) protocol, yielded excellent image quality with improved signal to noise ratio in peripheral brain regions and enhanced uniformity of contrast compared with standard excitation. Greatest performance enhancement was achieved using parallel transmission, but single channel transmission offers significant improvement over standard excitation pulses. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Spatially dependent filtering for removing phase distortions at the cortical surface
Authors: Ng Amanda , Johnston Leigh , Chen Zhaolin , Cho Zang‐Hee , Zhang Jingxin , Egan Gary 
Published: August 2011

AbstractRecent advances in high field magnetic resonance technology have increased the interest in the phase of the complex data. Processed phase images are derived from the phase signal by removing the bias field and phase wraps from the initial data. However, the usefulness of this data has been hindered by artifacts at the brain/non‐brain surface, particularly in cortical regions. A method is proposed that efficiently removes surface artifacts by performing Gaussian filtering with spatially varying parameters of unwrapped or complex filtered phase images. The proposed method is shown to produce improved images, revealing underlying structure and detail that are otherwise obscured by surface artifacts in images produced by traditional phase processing methods. Magn Reson Med 66:784–793, 2011. © 2011 Wiley‐Liss, Inc.
Practical and analytical approaches for designing scalable on‐demand policy‐based resource allocation in stateless IP networks
Authors: Haddadou Kamel , Ghamri‐Doudane Samir , Ghamri‐Doudane Yacine , Agoulmine Nazim 
Published: August 2011

SUMMARYToday the policy‐based management (PBM) approach is recognized as an efficient solution to simplify the complex task of managing and controlling networks. To this end, the Internet Engineering Task Force (IETF) has introduced a reference framework to build PBM systems. However, this framework only addresses the provisioning of relatively long validity period services based on predefined service‐level agreements. Furthermore, very little work addresses the scalability properties of the instantiation of this framework in a real network. This work aims to extend the IETF PBM framework in order to support dynamic provisioning of short‐term services (end‐system signalling) as well as an instantiation scheme that is scalable (distributed provisioning of edge routers). This instantiation scheme is based on the distribution of the provisioning process while keeping centralized only the parts that involve critical resources, namely bandwidth brokerage. The performance properties of the proposed scheme are then demonstrated throughout both extensive experimentation and an analytical study. The extension of this performance analysis to the case where multiple bandwidth brokers are used is also discussed. The results of this work are intended to be used as a guideline to help network operators to design a scalable PBM system in order to offer to their customers services with quality of service assurance on an on‐demand basis. Copyright © 2011 John Wiley & Sons, Ltd.
Boards and Cords: Discriminating Types of Artificial Cranial Deformation in Prehispanic South Central Andean Populations
Authors: O'Brien T. G. , Stanley A. M. 
Published: August 2011

ABSTRACTFor over a century, a number of ambiguous typologies have been employed to distinctly categorise types of artificial cranial deformation. This paper provides a quantitative method, based on multiple dimensions and discriminant function analysis, by which to assign skulls not only into discrete categories: deformed or not, but also by type: annular or tabular. A series of prehispanic, adult, human crania (n = 469) from archaeological sites in Argentina, Bolivia, Chile and Peru represented by both normal and artificially deformed specimens, provide craniometric data for four measurements across the vault: maximum cranial length, breadth and height and the frontal chord. These data are used to develop three indices which in turn are used to compute two discriminant functions. Results are plotted on a territorial map whereby the type of deformity can be determined. When these methods were applied to a comparative cranial sample of nondeformed skulls from South America, 100% of the samples was found to be nondeformed. When these methods were applied to the samples which were subjectively classified a priori by the first author as nondeformed, 81.3% of the samples were found to be nondeformed. This study demonstrates the value of a more objective and quantitative method by which to classify artificial cranial deformation, and thus provides a new approach. Copyright © 2011 John Wiley & Sons, Ltd.
Chaetophractus villosus: A Disturbing Agent for Archaeological Contexts
Authors: Frontini R. , Escosteguy P. 
Published: August 2011

ABSTRACTChaetophractus villosus (Dasypodidae), a medium‐sized armadillo with burrowing habits, is one of the natural agents whose activities play a major role in archaeological deposit disturbance in the Pampean Region in Argentina. This paper presents the results of a comparative analysis between the archaeological materials collected from 32 currently active burrows and the remains collected in the sedimentary matrix identified as burrow filling during excavations of El Guanaco Site 1, Sector 1. As a general tendency, it was possible to establish that C. villosus removes both lithic and faunal materials that are 3 cm long or less. As an exception, materials up to 7 cm long are displaced. The distribution observed during the excavation of currently active burrows indicates that materials concentrate around the burrows' entrances. Copyright © 2011 John Wiley & Sons, Ltd.
Towards global solutions of optimal discrete‐valued control problems
Authors: Woon Siew Fang , Rehbock Volker , Loxton Ryan 
Published: August 2011

SUMMARYThis paper proposes a new heuristic approach for solving optimal discrete‐valued control problems. We illustrate the approach with an existing hybrid power system model. The problem of choosing an operating schedule to minimize generator, battery, and switching costs is first posed as a mixed discrete dynamic optimization problem. Then, a discrete filled function method is employed in conjunction with a computational optimal control technique to solve this problem. Computational results indicate that this approach is robust, efficient, and can successfully identify a near‐global solution for this complex applied optimization problem despite the presence of multiple local optima. Copyright © 2011 John Wiley & Sons, Ltd.
Extension‐induced mechanical reinforcement in melt‐spun fibers of polyamide 66/multiwalled carbon nanotube composites
Authors: Mai Fang , Pan Dongdong , Gao Xiang , Yao Meijun , Deng Hua , Wang Ke , Chen Feng , Fu Qiang 
Published: August 2011

AbstractIn this work, polyamide 66 (PA66) and its composites with multiwalled carbon nanotubes (MWNTs) were melt spun into fibers at different draw ratios. PA66 fibers at high draw ratio demonstrate a 40% increase in tensile strength, 66% increase in modulus and a considerable increase in toughness. It is demonstrated that this reinforcement can be mainly attributed to high‐draw‐ratio‐induced good dispersion and orientation of MWNTs, particularly the enhanced interfacial adhesion between MWNT and matrix thanks to interfacial crystallization. Our work provides a simple but efficient method to achieve good dispersion and strong interfacial interaction through melt spinning. Copyright © 2011 Society of Chemical Industry