bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of phenylurea herbicides oxidation by Fenton and photo‐Fenton processes
Authors: Benitez F Javier , Real Francisco J , Acero Juan L , Garcia Carolina , Llanos Eva M 
Published: December 2006

AbstractThe chemical oxidation of four selected phenylurea herbicides (linuron, chlortoluron, diuron, and isoproturon) was studied by means of the Fenton system. The influence of the initial concentrations of hydrogen peroxide and ferrous ions, the pH and the type of buffer (perchloric acid/perchlorate, acetic acid/acetate, or phosphoric acid/phosphate) was established according to the degradation levels obtained. In the kinetic study, the general decomposition reaction was divided into two stages with different reaction rates, which was justified by considering the whole reaction mechanism for this system. In this kinetic study, a competition kinetics model, which usedp‐chlorobenzoic acid as a reference compound, was applied for the evaluation of the rate constants for each reaction between the herbicides and the hydroxyl radical. The proposed values for these rate constants are: 7.5 × 109L mol−1s−1for chlortoluron, 5.6 × 109L mol−1s−1for linuron, 7.1 × 109L mol−1s−1for diuron and 5.7 × 109L mol−1s−1for isoproturon. Finally, some experiments with the photo‐Fenton system reveal increases in the decomposition levels of the herbicides, due to additional generation reactions of hydroxyl radicals. Copyright © 2007 Society of Chemical Industry
Microbial fuel cells utilising carbohydrates
Authors: Scott Keith , Murano Cassandro 
Published: December 2006

AbstractThe paper reports results of a mediatorless microbial fuel cell (MFC), utilising waste carbohydrate (manure) as a fuel, which did not use a catalyst or a proton exchange membrane and is thus environmentally friendly (by using no toxic substances) in treating waste. The cell used a manure sludge in the anode compartment and an aqueous salt solution (seawater) containing dissolved oxygen. The influence of the geometric position of the anode and cathode, both made of carbon cloth, had a major effect on the fuel cell power performance. The maximum power density obtained with the cell was 4.21 mW m−2. The paper also reports results of a mediated MFC using a yogurt bacteria and methylene blue as mediator. This cell produced a maximum power density of over 13 mW m−2. This power output compares quite favourably with that achieved with the same cell using glucose as fuel with E. coli (peak power density of 180 mW m−2). Copyright © 2007 Society of Chemical Industry
Comparison of diverged Hoxc8 early enhancer activities reveals modification of regulatory interactions at conserved cis‐acting elements
Authors: Shashikant Cooduvalli S. , Bolanowsky Stacey A. , Anand Sanjay , Anderson Shawn M. 
Published: December 2006

AbstractThe Hoxc8 early enhancer that controls the initiation and establishment of Hoxc8 expression in the developing mouse embryo is found in different vertebrate lineages including mammals, birds and fish. Mouse and Fugu Hoxc8 early enhancers (200 bp) have diverged in the composition of elements located towards the 3′ region. However, they share cis‐acting elements A–E located in the 5′ region. Mutations at these elements in the context of the mouse Hoxc8 early enhancer affect reporter gene expression in the posterior neural tube, somites and lateral plate mesoderm of day 9.5 mouse embryos. Here, we demonstrate that mutations introduced at the same elements but in the context of the Fugu Hoxc8 early enhancer had different consequences on the reporter gene expression in transgenic mouse embryos. Furthermore, in contrast to the mouse enhancer the Fugu enhancer does not utilize elements D and E in achieving posterior neural tube and somite expression. These results suggest that the diverged sequences prevent regulatory interactions at conserved cis‐acting elements. We propose that divergent sequences modify regulatory interactions at conserved elements by providing a “contextual change”. Our finding that the enhancer elements do not act in a unitary fashion but function in the context of the surrounding sequence brings a new dimension to the study of cis‐regulatory evolution. J. Exp. Zool. (Mol. Dev. Evol.) 308B:242–249, 2007. © 2006 Wiley‐Liss, Inc.
Characterization of breast lesions using the 3D FIESTA sequence and contrast‐enhanced magnetic resonance imaging
Authors: Klifa Catherine S. , Shimakawa Ann , Siraj Zaker , Gibbs Jessica E. , Wilmes Lisa J. , Partridge Savannah C. , Proctor Evelyn , Hylton Nola M. 
Published: December 2006

AbstractPurposeTo determine whether combining 3D fast imaging employing steady‐state acquisition (FIESTA) and T1‐weighted contrast‐enhanced (CE) sequences could help characterize lesions in 32 women with benign, in situ, or invasive breast lesions. Since FIESTA provides both T1 and T2 information on the same three‐dimensional (3D) matrix as high‐resolution T1‐weighted dynamic data, we aimed to verify whether invasive lesions could be separated from in situ and/or benign lesions using quantitative FIESTA measures of tissue intensity and homogeneity.Material and MethodsWith the use of CE‐MRI data, regions of interest (ROIs) were manually delineated in enhancing lesions and on surrounding normal tissue. These ROIs were then applied to 3D FIESTA data. Quantitative measures between lesion and normal tissue were compared among the lesion groups.ResultsOn FIESTA most invasive cancer lesions were hypointense compared to surrounding normal tissue (mean lesion intensity was 89% of normal tissue intensity), whereas most ductal and benign lesions appeared hyperintense compared to surrounding normal tissue (lesions at 100.9% and 121.9% of normal tissue intensity, respectively). Measures obtained from resampled T2‐weighted data showed no significant differences between the invasive and benign lesion groups.ConclusionWe detected significant differences between invasive and noninvasive lesions by quantifying intensity differences between the lesions and surrounding normal tissue on FIESTA. J. Magn. Reson. Imaging 2007. © 2006 Wiley‐Liss, Inc.
In vivo brain edema classification: New insight offered by large b‐value diffusion‐weighted MR imaging
Authors: Schwarcz Attila , Ursprung Zsuzsa , Berente Zoltan , Bogner Peter , Kotek Gyula , Meric Philippe , Gillet Brigitte , Beloeil Jean‐Claude , Dóczi Tamás 
Published: December 2006

AbstractPurposeTo assess the role of large b‐value diffusion weighted imaging (DWI) in the characterization of the physicochemical properties of the water in brain edema under experimental and clinical conditions.Materials and MethodsVasogenic brain edema was induced in mice by means of cold injury. A total of 17 patients with extensive peritumoral brain edema were also investigated. The longitudinal relaxation time (T1) and apparent diffusion coefficient (D) were measured in the edematous area both in humans and in mice. D was calculated by using both mono‐ (Dmono) and biexponential (Dfast and Dslow) approaches in the low and overall range of b‐values, respectively. The D values were correlated with the T1 values.ResultsA strong linear correlation was found between T1 and Dmono in vasogenic brain edema, both in humans and in mice. After breakdown of Dmono into fast and slow diffusing components, only Dfast exhibited a strong correlation with T1; Dslow was unchanged in vasogenic brain edema.ConclusionLarge b‐value DWI can furnish a detailed characterization of vasogenic brain edema, and may provide a quantitative approach for the differentiation of edema types on the basis of the physicochemical properties of the water molecules. Application of the DWI method may permit prediction and follow‐up of the effects of antiedematous therapy. J. Magn. Reson. Imaging 2007. © 2006 Wiley‐Liss, Inc.
Dynamic contrast‐enhanced MRI study of male pelvic perfusion at 3T: Preliminary clinical report
Authors: Hou Ping , De Elise J.B. , Kramer Larry A. , Westney O. Lenaine 
Published: December 2006

AbstractPurposeTo detect male pelvic perfusion in patients with coronary artery disease (CAD) vs. controls by dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) at 3T.Materials and MethodsEighteen male patients were studied with T1‐weighted (T1W) DCE‐MRI to measure perfusion, phase‐contrast (PC) imaging to measure bulk flow, and contrast‐enhanced (CE)‐MRA to detect stenosis. Regions of interest (ROIs) in prostate, corpus cavernosal, and spongiosal tissues were analyzed. Two‐compartment pharmacokinetic modeling was employed to fit the signal enhancement. Perfusion parameters were analyzed by curve‐fitting and utilized to compare the CAD and control groups. Validated questionnaires measuring urinary and erectile function were used to evaluate pelvic symptomatology in both groups.ResultsMean perfusion analysis confirmed weaker and slower enhancement in CAD patients vs. controls despite equivalent cardiac output values. The mean maximum enhancement was 26.33 ± 0.12 (controls) vs. 22.38 ± 0.44 (CAD) for prostate. The mean wash‐in rate in units of minute–1 was 62.10 ± 1.74 (controls) vs. 34.44 ± 1.08 (CAD) for prostate, 16.68 ± 0.72 (controls) vs. 8.04 ± 0.36 (CAD) for spongiosal, and 8.34 ± 0.54 (controls) vs. 3.48 ± 0.24 (CAD) for cavernosal tissues (all with P < 0.0001).ConclusionThis preliminary study demonstrates that perfusion parameters differ between CAD and control patients, and the findings mirror the differences in pelvic symptoms in these groups. J. Magn. Reson. Imaging 2007. © 2006 Wiley‐Liss, Inc.
Glutamatergic synaptic depression by synthetic amyloid β‐peptide in the medial septum
Authors: Santos‐Torres Julio , Fuente Antonio , Criado Jose Maria , Riolobos Adelaida Sanchez , Heredia Margarita , Yajeya Javier 
Published: December 2006

AbstractThe medial septum/diagonal band region, which participates in learning and memory processes via its cholinergic and GABAergic projection to the hippocampus, is one of the structures affected by beta amyloid (βA) deposition in Alzheimer's disease (AD). The acute effects of βA (25–35 and 1–40) on action potential generation and glutamatergic synaptic transmission in slices of the medial septal area of the rat brain were studied using current and patch‐clamp techniques. The βA mechanism of action through M1 muscarinic receptors and voltage‐dependent calcium channels was also addressed. Excitatory evoked responses decreased (30–60%) in amplitude after βA (2 μM) perfusion in 70% of recorded cells. However, the firing properties were unaltered at the same concentration. This depression was irreversible in most cases, and was not prevented or reversed by nicotine (5 μM). In addition, the results obtained using a paired‐pulse protocol support pre‐ and postsynaptic actions of the peptide. The βA effect was blocked by calcicludine (50 nM), a selective antagonist of L‐type calcium channels, and also by blocking muscarinic receptors with atropine (5 μM) or pirenzepine (1 μM), a more specific M1‐receptor blocker. We show that in the medial septal area this oligomeric peptide acts through calcium channels and muscarinic receptors. As blocking any of these pathways blocks the βA effects, we propose a joint action through both mechanisms. These results may contribute to a better understanding of the pathophysiology at the onset of AD. This understanding will be required for the development of new therapeutic agents. © 2006 Wiley‐Liss, Inc.
Fischer decomposition and special solutions for the parabolic Dirac operator
Authors: Cerejeiras P. , Sommen F. , Vieira N. 
Published: December 2006

AbstractIn this paper we study a Fischer decomposition for the parabolic Dirac operator which factorizes the heat equation. Since the standard construction techniques are not valid in our case, due to the non‐homogeneity of the positive parabolic Dirac operator, we first establish and study the Fischer decomposition for the homogeneous part of the parabolic Dirac operator. Finally, we construct null‐solutions of the parabolic Dirac operator by means of series expansions in terms of cylindrical co‐ordinates. Copyright © 2006 John Wiley & Sons, Ltd.
A comparative study of multilayer perceptron neural networks for the identification of rhubarb samples
Authors: Zhang Zhuoyong , Wang Yamin , Fan Guoqiang , Harrington Peter De B. 
Published: December 2006

AbstractArtificial neural networks have gained much attention in recent years as fast and flexible methods for quality control in traditional medicine. Near‐infrared (NIR) spectroscopy has become an accepted method for the qualitative and quantitative analyses of traditional Chinese medicine since it is simple, rapid, and non‐destructive. The present paper describes a method by which to discriminate official and unofficial rhubarb samples using three layer perceptron neural networks applied to NIR data. Multilayer perceptron neural networks were trained with back propagation, delta‐bar‐delta and quick propagation algorithms. Results obtained using these methods were all satisfactory, but the best outcomes were obtained with the delta‐bar‐delta algorithm. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis of macromonomers of acrylic acid by telomerization: Application to the synthesis of polystyrene‐g‐poly(acrylic acid) copolymers
Authors: Boyer Cyrille , Boutevin Gilles , Robin Jean‐Jacques , Boutevin Bernard 
Published: December 2006

AbstractThe synthesis of macromonomers of acrylic acid was performed by telomerization in a three‐step process. The first step was the telomerization of tert‐butyl acrylate in the presence of thioglycolic acid. Different molecular weights were obtained with different ratios of the monomer to the transfer agent. Good control of the molecular weights and architectures of the oligomers (e.g., the presence of an acid function on the chain end) was observed. The transfer constant of tert‐butyl acrylate with thioglycolic acid was assessed (chain‐transfer constant = 0.6). In the second step, the terminal unsaturation of the oligomers was obtained by the reaction of the terminal acid groups with 2‐isocyanatoethyl methacrylate to yield the macromonomers of tert‐butyl acrylate. In the last step, the tert‐butyl acrylate groups were hydrolyzed in the presence of trifluoroacetic acid at room temperature. The macromonomers were copolymerized with styrene to obtain graft copolymers, and the reactivity ratios were evaluated. Finally, the copolymers were characterized with surface electron microscopy and atom force microscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 395–415, 2007
Synthesis of poly(vinyl acetate)‐graft‐polystyrene by a combination of cobalt‐mediated radical polymerization and atom transfer radical polymerization
Authors: Kaneyoshi Hiromu , Matyjaszewski Krzysztof 
Published: December 2006

AbstractVinyl acetate and vinyl chloroacetate were copolymerized in the presence of a bis(trifluoro‐2,4‐pentanedionato)cobalt(II) complex and 2,2′‐azobis(4‐methoxy‐2,4‐dimethylvaleronitrile) at 30 °C, forming a cobalt‐capped poly(vinyl acetate‐co‐vinyl chloroacetate). The addition of 2,2,6,6‐tetramethyl‐1‐piperidinyloxy after a certain degree of copolymerization was reached afforded 2,2,6,6‐tetramethyl‐1‐piperidinyloxy‐terminated poly(vinyl acetate‐co‐vinyl chloroacetate) (PVOAc–MI; number‐average molecular weight = 31,000, weight‐average molecular weight/number‐average molecular weight = 1.24). A 1H NMR study of the resulting PVOAc–MI revealed quantitative terminal 2,2,6,6‐tetramethyl‐1‐piperidinyloxy functionality and the presence of 5.5 mol % vinyl chloroacetate in the copolymer. The atom transfer radical polymerization (ATRP) of styrene (St) was studied with ethyl chloroacetate as a model initiator and five different Cu‐based catalysts. Catalysts with bis(2‐pyridylmethyl)octadecylamine (BPMODA) or tris(2‐pyridylmethyl)amine (TPMA) ligands provided the highest initiation efficiency and best control over the polymerization of St. The grafting‐from ATRP of St from PVOAc–MI catalyzed by copper complexes with BPMODA or TPMA ligands provided poly(vinyl acetate)‐graft‐polystyrene copolymers with relatively high polydispersity (>1.5) because of intermolecular coupling between growing polystyrene (PSt) grafts. After the hydrolysis of the graft copolymers, the cleaved PSt side chains had a monomodal molecular weight distribution with some tailing toward the lower number‐average molecular weight region because of termination. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 447–459, 2007
Preparation of poly(styrene‐co‐acrylonitrile)‐grafted multiwalled carbon nanotubes via surface‐initiated atom transfer radical polymerization
Authors: Shanmugharaj A. M. , Bae J. H. , Nayak Rati Ranjan , Ryu Sung Hun 
Published: December 2006

AbstractThe in situ grafting‐from approach via atom transfer radical polymerization was successfully applied to polystyrene, poly(styrene‐co‐acrylonitrile), and polyacrylonitrile grafted onto the convex surfaces of multiwalled carbon nanotubes (MWCNTs) with (2‐hydroxyethyl 2‐bromoisobutyrate) as an initiator. Thermogravimetric analysis showed that effective functionalization was achieved with the grafting approach. The grafted polymers on the MWCNT surface were characterized and confirmed with Fourier transform infrared spectroscopy and nuclear magnetic resonance. Raman and near‐infrared spectroscopy revealed that the grafting of polystyrene, poly(styrene‐co‐acrylonitrile), and polyacrylonitrile slightly affected the side‐wall structures. Field emission scanning electron microscopy showed that the carbon nanotube surface became rough because of the grafting of the polymers. Differential scanning calorimetry results indicated that the polymers grafted onto MWCNTs showed higher glass‐transition temperatures. The polymer‐grafted MWCNTs exhibited relatively good dispersibility in an organic solvent such as tetrahydrofuran. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 460–470, 2007
Synthesis of optically active poly(N‐propargylsulfamides) with helical conformation
Authors: Zhang Zhigang , Deng Jianping , Zhao Weiguo , Wang Jianmin , Yang Wantai 
Published: December 2006

AbstractA novel chiral N‐propargylsulfamide monomer (1a) and its enantiomer (1b) were synthesized and polymerized with (nbd)Rh+B−(C6H5)4 as a catalyst providing poly(1) (poly(1a) and poly(1b)) in high yields (≥99%). Poly(1) could take stable helices in less polar solvents (chloroform and THF), demonstrated by strong circular dichroism signals and UV–vis absorption peaks at about 415 nm and the large specific rotations; but in more polar solvents including DMF and DMSO, poly(1) failed to form helix. Quantitative evaluation with anisotropy factor showed that the helical screw sense had a relatively high thermal stability. These results together with the IR spectra measured in solvents showed that hydrogen bonding between the neighboring sulfamide groups is one of the main driving forces for poly(1) to adopt stable helices. In addition, copolymerization of monomer 1a and monomer 2 was conducted, the solubility of poly(1) was improved drastically. However, the copolymerization had adverse effects on the formation of stable helices in the copolymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 500–508, 2007
Stability control of the electrooptic effect with new maleimide copolymers containing photoreactive tricyanopyrrolidene‐based chromophores
Authors: Lee Sang Kyu , Cho Min Ju , Jin Jung‐Il , Choi Dong Hoon 
Published: December 2006

AbstractNew photocrosslinkable maleimide copolymers have been synthesized by the attachment of a tricyanopyrrolidene‐based chromophore. The 2‐(3‐cyano‐4‐(2‐{4‐[hexyl‐(6‐hydroxy‐hexyl)‐amino]‐phenyl}‐vinyl)‐5‐oxo‐1‐{4‐[4‐(3‐oxo‐3‐phenyl‐propenyl)‐ phenoxy]‐butyl}‐1,5‐dihydro‐pyrrol‐2‐ylidene)‐malononitrile chromophore exhibits nonlinear optical activity and contains a chalcone moiety that is sensitive to UV light (λ = 330–360 nm) for crosslink formation. The maleimide monomers have also been functionalized with chalcone moieties. The resultant copolymers exhibit great processability, and one of them shows a maximum electrooptic coefficient of 90 pm/V at 1300 nm. We could control the thermal stability of the electrooptic coefficient with the newly synthesized photoreactive copolymers successfully. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 531–542, 2007
Interaction of malaria parasite‐inhibitory antibodies with the merozoite surface protein MSP119 by computational docking
Authors: Autore Flavia , Melchiorre Sara , Kleinjung Jens , Morgan William D. , Fraternali Franca 
Published: December 2006

AbstractMerozoite surface protein 1 (MSP1) of the malaria parasite Plasmodium falciparum is an important vaccine candidate antigen. Antibodies specific for the C‐terminal maturation product, MSP119, have been shown to inhibit erythrocyte invasion and parasite growth. Specific monoclonal antibodies react with conformational epitopes contained within the two EGF‐like domains that constitute the antigen MSP119. To gain greater insight into the inhibitory process, the authors selected two strongly inhibitory antibodies (designated 12.8 and 12.10) and modeled their structures by homology. Computational docking was used to generate antigen–antibody complexes and a selection filter based on NMR data was applied to obtain plausible models. Molecular Dynamics simulations of the selected complexes were performed to evaluate the role of specific side chains in the binding. Favorable complexes were obtained that complement the NMR data in defining specific binding sites. These models can provide valuable guidelines for future experimental work that is devoted to the understanding of the action mechanism of invasion‐inhibitory antibodies. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Sublinear‐time approximation algorithms for clustering via random sampling
Authors: Czumaj Artur , Sohler Christian 
Published: December 2006

AbstractWe present a novel analysis of a random sampling approach for four clustering problems in metric spaces:k‐median,k‐means,min‐sum k‐clustering, and balancedk‐median. For all these problems, we consider the following simple sampling scheme: select a small sample set of input points uniformly at random and then run some approximation algorithm on this sample set to compute an approximation of the best possible clustering of this set. Our main technical contribution is a significantly strengthened analysis of the approximation guarantee by this scheme for the clustering problems.The main motivation behind our analyses was to design sublinear‐time algorithms for clustering problems. Our second contribution is the development of new approximation algorithms for the aforementioned clustering problems. Using our random sampling approach, we obtain for these problems the first time approximation algorithms that have running time independent of the input size, and depending onkand the diameter of the metric space only. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2006
Density profile unfolding from Compton scattering measurements in reflection geometry
Authors: Fernández Jorge E. , Badiali Marco , Guidetti Alessandro , Scot Viviana 
Published: December 2006

AbstractIn this article, we report a mathematical procedure that allows the unfolding of the density profile from the measurement of an integrated scattering signal containing predominantly the Compton component. An experimental device (patent claimed) has been used for the measurements. It uses a radiation source with white x‐ray spectrum (unpolarized) and the reflection geometry to maximize the Compton signal. The algorithm has been tested on light‐element, inhomogeneous samples of uniform and non‐uniform densities. Incomplete primary volume and multiple scattering corrections are also discussed. The resulting density profiles are in good agreement with direct measurements of profiles performed with other means. Copyright © 2006 John Wiley & Sons, Ltd.