bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variable stimulation patterns for poststroke hemiplegia
Authors: Doucet Barbara M. , Griffin Lisa 
Published: December 2008

AbstractNeuromuscular electrical stimulation can improve motor function in those affected by paralysis, but its use is limited by a high rate of muscular fatigue. Variable stimulation patterns have been examined in young adults with and without spinal cord injury, but much less investigation has been devoted to studying the effects of variable stimulation patterns administered to older adults or those paralyzed by stroke. Significant changes occur in the neuromuscular system with age that may affect the response to variable stimulation patterns. We administered three, 3‐min intermittent stimulation patterns to the median nerves of 10 individuals with hemiplegia from stroke and 10 age‐matched able‐bodied adults: (1) constant 20 HZ, (2) a pattern that began at 20 HZand progressively increased to 40 HZin the latter half of the task, and (3) a 20‐HZpattern that switched to a 20‐HZdoublet pattern after 90 s. In the able‐bodied group the doublet pattern produced significantly higher force time integrals (FTI) (1409.72 ± 3.15 N · s) than the 20–40‐HZpattern (1067.46 ± 1.15 N · s) or the 20‐HZpattern (831 ± 1.87 N · s). In the poststroke individuals the doublet pattern also produced the highest FTI (724.04 ± 2.02 N · s), and there was no significant difference between the 20–40‐HZ(636.42 ± 1.65 N · s) and 20‐HZ(583.64 ± 3.02 N · s) patterns. These results indicate that protocols that incorporate doublets in the later stages of fatigue are effective in older adults and in older adults with paralysis from stroke. © 2009 Wiley Periodicals, Inc. Muscle Nerve 39: 54–62, 2009
Neuromuscular control of lumbar instability following static work of various loads
Authors: Le Brook , Davidson Bradley , Solomonow Deborah , Zhou Bing He , Lu Yun , Patel Vikas , Solomonow Moshe 
Published: December 2008

AbstractNeuromuscular control of lumbar stability following exposure to prolonged static work, under low and high loads, was assessed in the in vivo feline model. Six sessions of 10 min work at 20N with 10 min between rest was compared to a group subjected to the same protocol but carrying high loads of 60N. Displacement and tension developed in the spine at the instant the multifidus muscles applied stabilizing contractions, and their amplitudes were obtained from their electromyogram (EMG). Significant (P < 0.001) laxity developed in the various viscoelastic tissues of the lumbar spine that did not recover during and up to 7 h of rest postwork. Simultaneously, there was a significant (P < 0.001) decrease in muscular activity in the 3–4 h immediately postwork under low load but only during the first hour in the high load group. After that period the musculature compensated for the laxity of the viscoelastic tissues by a significant (P < 0.001) increase in activity in the high‐load group and a nonsignificant increase in the low group. It was concluded that during 1–3 h immediately poststatic work a significant decrease in the stabilizing function of viscoelastic tissues together with a significant decrease in muscular activity is present, and they render the spine unstable and exposed to high risk of injury. Performance of prolonged static work under low loads, while not harmful during the work, cannot be designated as a “no‐risk” condition, as it may result in injury postwork. Muscle Nerve 39: 71–82, 2009
Proton MRS of the breast in the clinical setting
Authors: Mountford Carolyn , Ramadan Saadallah , Stanwell Peter , Malycha Peter 
Published: December 2008

AbstractInformation for determining whether a primary breast lesion is invasive and its receptor status and grade can be obtained before surgery by performing proton MRS on a fine‐needle aspiration biopsy (FNAB) specimen and analyzing the MRS information by a pattern recognition method. Two‐dimensional MRS, on either specimens or cells, allows the unambiguous assignment of most resonances. When correlated with the spectral regions selected by the pattern recognition method, there are strong indications for the biochemical markers responsible for prognostic information of invasive capacity and metastatic spread. Spectral assignments and biological correlations can be made using cell models. In vivo MRS can distinguish invasive from benign lesions. This pathological distinction can be made from the presence of resonances at discrete frequencies. To achieve this level of spectral resolution and signal‐to‐noise ratio, there are stringent requirements when acquiring and processing the data. The challenge now is to implement two‐dimensional MRS in vivo. Until this is realized, the combination of in vivo MR, for diagnosis and spatial location, and MRS, for image‐guided biopsy to provide information on tumor spread, promises to provide a higher level of preoperative diagnosis than previously achieved. Copyright © 2008 John Wiley & Sons, Ltd.
Investigation of breast cancer using two‐dimensional MRS
Authors: Thomas M. Albert , Lipnick Scott , Velan S. Sendhil , Liu Xiaoyu , Banakar Shida , Binesh Nader , Ramadan Saadallah , Ambrosio Art , Raylman Raymond R. , Sayre James , DeBruhl Nanette , Bassett Lawrence 
Published: December 2008

AbstractProton (1H) MRS enables non‐invasive biochemical assay with the potential to characterize malignant, benign and healthy breast tissues. In vitro studies using perchloric acid extracts and ex vivo magic angle spinning spectroscopy of intact biopsy tissues have been used to identify detectable metabolic alterations in breast cancer. The challenges of 1H MRS in vivo include low sensitivity and significant overlap of resonances due to limited chemical shift dispersion and significant inhomogeneous broadening at most clinical magnetic field strengths. Improvement in spectral resolution can be achieved in vivo and in vitro by recording the MR spectra spread over more than one dimension, thus facilitating unambiguous assignment of metabolite and lipid resonances in breast cancer. This article reviews the recent progress with two‐dimensional MRS of breast cancer in vitro, ex vivo and in vivo. The discussion includes unambiguous detection of saturated and unsaturated fatty acids, as well as choline‐containing groups such as free choline, phosphocholine, glycerophosphocholine and ethanolamines using two‐dimensional MRS. In addition, characterization of invasive ductal carcinomas and healthy fatty/glandular breast tissues non‐invasively using the classification and regression tree (CART) analysis of two‐dimensional MRS data is reviewed. Copyright © 2008 John Wiley & Sons, Ltd.
Concurrently coupled atomistic and XFEM models for dislocations and cracks
Authors: Gracie Robert , Belytschko Ted 
Published: December 2008

AbstractA method for the modeling of dislocations and cracks by atomistic/continuum models is described. The methodology combines the extended finite element method with the bridging domain method (BDM). The former is used to model crack surfaces and slip planes in the continuum, whereas the BDM is used to link the atomistic models with the continuum. The BDM is an overlapping domain decomposition method in which the atomistic and continuum energies are blended so that their contributions decay to their boundaries on the overlapping subdomain. Compatibility between the continua and atomistic domains is enforced by a continuous Lagrange multiplier field. The methodology allows for simulations with atomistic resolution near crack fronts and dislocation cores while retaining a continuum model in the remaining part of the domain and so a large reduction in the number of atoms is possible. It is applied to the modeling of cracks and dislocations in graphene sheets. Energies and energy distributions compare very well with direct numerical simulations by strictly atomistic models. Copyright © 2008 John Wiley & Sons, Ltd.
On methods for stabilizing constraints over enriched interfaces in elasticity
Authors: Sanders Jessica D. , Dolbow John E. , Laursen Tod A. 
Published: December 2008

AbstractEnriched finite element approaches such as the extended finite element method provide a framework for constructing approximations to solutions of non‐smooth problems. Internal features, such as boundaries, are represented in such methods by using discontinuous enrichment of the standard finite element basis. Within such frameworks, however, imposition of interface constraints and/or constitutive relations can cause unexpected difficulties, depending upon how relevant fields are interpolated on un‐gridded interfaces. This work address the stabilized treatment of constraints in an enriched finite element context.Both the Lagrange multiplier and penalty enforcement of tied constraints for an arbitrary boundary represented in an enriched finite element context can lead to instabilities and artificial oscillations in the traction fields. We demonstrate two alternative variational methods that can be used to enforce the constraints in a stable manner. In a ‘bubble‐stabilized approach,’ fine‐scale degrees of freedom are added over elements supporting the interface. The variational form can be shown to have a similar form to a second approach we consider, Nitsche's method, with the exception that the stabilization terms follow directly from the bubble functions.In this work, we examine alternative variational methods for enforcing a tied constraint on an enriched interface in the context of two‐dimensional elasticity. We examine several benchmark problems in elasticity, and show that only Nitsche's method and the bubble‐stabilization approach produce stable traction fields over internal boundaries. We also demonstrate a novel difference between the penalty method and Nitsche's method in that the latter passes the patch test exactly, regardless of the stabilization parameter's magnitude. Results for more complicated geometries and triple interface junctions are also presented. Copyright © 2008 John Wiley & Sons, Ltd.
Comparative study of paclitaxel physically encapsulated in and chemically conjugated with PEG‐PLA
Authors: Xu Xiaoyi , Zhang Xuefei , Wang Xiuhong , Li Yuxin , Jing Xiabin 
Published: December 2008

AbstractPaclitaxel‐loaded poly(ethylene glycol)‐b‐poly(l‐lactide (LA)) (PEG‐PLA) micelles were prepared by two methods. One is physical encapsulation of paclitaxel in micelles composed of a PEG‐PLA block copolymer and the other is based on a PEG‐PLA–paclitaxel conjugate, abbreviated as “conjugate micelles”. Their physicochemical characteristics, e.g. critical micelle concentration (CMC), morphology, and micelle size distribution were then evaluated by means of fluorescence spectroscopy, scanning electron microscopy (SEM), and dynamic light scattering (DLS). The results show that the CMC of PEG‐PLA–paclitaxel and PEG‐PLA are 6.31 × 10−4 and 1.78 × 10−3 g L−1, respectively. Both micelles assume a spherical shape with comparable diameters and have unimodal size distribution. Moreover, invitro drug delivery behavior was studied by high performance liquid chromatography (HPLC). The antitumor activity of the paclitaxel‐loaded micelles against human liver cancer H7402 cells was evaluated by 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) method. The conjugate micelles show a lower burst release during the initial stage and higher accumulative release amount of paclitaxel after a period of time while the encapsulated ones behave in the opposite way. Both the paclitaxel‐loaded micelles showed comparable anticancer efficacy with the free drug. Copyright © 2008 John Wiley & Sons, Ltd.
Tribological properties of epoxy/polyurea composite
Authors: Hu Haixia , Yu Sirong , Wang Mingyu , Ma Jun , Liu Kaixin 
Published: December 2008

AbstractThe tribological behavior of epoxy/polyurea composite under dry friction was investigated. The worn surface morphologies of epoxy and epoxy/polyurea composite have been analyzed using scanning electron microscopy (SEM), and the functional group of epoxy and epoxy/polyurea composite before and after wear have been analyzed by a Fourier transform infrared spectrometer (FT‐IR). It has been found that epoxy terminal groups, which exist in an epoxy molecule, can react with the end group amine of the polyurea copolymer, generating more HO bonds, which enhances the deformation capacity. Polyurea particles are dispersed uniformly in epoxy matrix before wear, while plastic deformation and distorted domains occur on the worn surface of epoxy/polyurea composite. This indicates that the wear resistance of epoxy/polyurea composite was greatly improved by the addition of polyurea elastomer, which led to low frictional coefficients and wear mass losses. Copyright © 2008 John Wiley & Sons, Ltd.
A novel cyanate ester resin/microcapsules system
Authors: Yuan Li , Gu Aijuan , Liang Guozheng 
Published: December 2008

AbstractPoly(urea‐formaldehyde) microcapsules filled with epoxy resins(MCEs) were applied to bisphenol A dicyanate ester (BADCy) resin to develop a novel BADCy/MCEs system. The effects of MCEs on the viscosity and the reactivity of BADCy were investigated. The mechanical properties and the hot water resistance of cured BADCy/MCEs systems were evaluated. The morphologies of the cured systems were characterized using a scanning electron microscope. The thermal property of cured systems was investigated using thermogravimetric analysis. The results indicate that MCEs may influence the reaction of BDACy. The proper addition of MCEs can significantly improve the mechanical property and the hot water resistance of cured BADCy resin. MCEs have a negative influence on the initial thermal decomposition temperature (Td) of cured BADCy resin. POLYM. COMPOS., 2010. © 2008 Society of Plastics Engineers.
Development of Nano‐TiO2 dye sensitised solar cells on high mobility transparent conducting oxide thin films
Authors: Bowers J. W. , Upadhyaya H. M. , Calnan S. , Hashimoto R. , Nakada T. , Tiwari A. N. 
Published: December 2008

AbstractThe optical transmission of dye‐sensitised solar cells (DSCs) can be tuned by altering the dye and/or particle size of the mesoporous TiO2 layers, to allow their application as the top device in tandem solar cells. To benefit from this semi‐transparency, parasitic optical losses by the transparent electrodes must be minimised. This work investigates the influence of using two different transparent conductors, namely, the high mobility material titanium doped indium oxide (ITiO) and fluorine doped tin oxide (FTO) as electrodes for semi‐transparent DSCs. The overall NIR transparency through the DSCs increased significantly as each FTO electrode was replaced by an ITiO electrode. This increase was from 20–45% in the 1300–700 nm wavelength range for fully FTO‐based cells, to about 60% for fully ITiO‐based cells, across the same spectrum. DSCs prepared on these electrodes exhibited short circuit currents ranging from 14·0–14·9 mA/cm2. The conversion efficiency of the cell with ITiO as both the front and rear electrodes was 5·8%, which though significant, was lower than the 8·2% attained by the cell using FTO electrodes, as a result of a lower fill factor. Improvements in the ITiO thermal stability and in the processing of the TiO2 interfacial layer are expected to improve the cell efficiency of such single DSC devices. The high current density and optical transparency of ITiO‐based DSCs make them an interesting option for tandem solar cells. Copyright © 2008 John Wiley & Sons, Ltd.
Chemistry of aryl N‐(2‐pyridyl) thionocarbamates in basic media
Authors: Silva Daniel , Norberto Fátima , Santos Susana , Hervés Pablo 
Published: December 2008

AbstractThree aryl N‐pyridylthionocarbamates were synthesized by thioacylation of 2‐aminopyridine and 2‐methylaminopyridine with the respective chlorothionoformates. Their hydrolysis mechanism was studied in aqueous basic media. The aryl N‐(2‐pyridyl)thionocarbamates are considerably less reactive than their oxo analogues, the aryl N‐(2‐pyridyl) carbamates, especially the N‐monosubstituted ones (1a‐b). Absence of significant buffer catalysis, isolation of the product resulting from trapping of the unsaturated intermediate with piperidine and the entropy of activation observed for the hydrolysis of compound 1b clearly indicate an E1cB mechanism for the N‐monosubstituted aryl N‐(2‐pyridyl)thionocarbamates. The experimental data suggest that the N,N‐disubstituted substrate (2) undergoes basic hydrolysis by a general base catalysed BAC2 mechanism. Copyright © 2008 John Wiley & Sons, Ltd.
Solubility behavior of amphiphilic block and random copolymers based on 2‐ethyl‐2‐oxazoline and 2‐nonyl‐2‐oxazoline in binary water–ethanol mixtures
Authors: Lambermont‐Thijs Hanneke M. L. , Hoogenboom Richard , Fustin Charles‐André , Bomal‐D'Haese Cécile , Gohy Jean‐François , Schubert Ulrich S. 
Published: December 2008

AbstractThe solution properties of random and block copolymers based on 2‐ethyl‐2‐oxazoline (EtOx) and 2‐nonyl‐2‐oxazoline (NonOx) were investigated in binary solvent mixtures ranging from pure water to pure ethanol. The solubility phase diagrams for the random and block copolymers revealed solubility (after heating), insolubility, dispersions, micellization as well as lower critical solution temperature (LCST) and upper critical solution temperature behavior. The random and block copolymers containing over 60 mol % pNonOx were found to be solubilized in ethanol upon heating, whereas the dissolution temperature of the block copolymers was found to be much higher than for the random copolymers due to the higher extent of crystallinity. Furthermore, the block copolymer containing 10 mol % pNonOx exhibited a LCST in aqueous solution at 68.7 °C, whereas the LCST for the random copolymer was found to be only 20.8 °C based on the formation of hydrophobic microdomains in the block copolymer. The random copolymer displayed a small increase in LCST up to a solvent mixture of 9 wt % EtOH, whereas further increase of ethanol led to a decrease in LCST, which is probably due to the “water‐breaking” effect causing an increased attraction between ethanol and the hydrophobic part of the copolymer. In addition, the EtOx‐NonOx block copolymers revealed the formation of micelles and dynamic light scattering demonstrated that the micellar size is increasing with increasing the ethanol content due to the enhanced solubility of EtOx. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 515–522, 2009
Long‐lived layered silicates‐immobilized 2,6‐bis(imino)pyridyl iron (II) catalysts for hybrid polyethylene nanocomposites by in situ polymerization: Effect of aryl ligand and silicate modification
Authors: Leone Giuseppe , Bertini Fabio , Canetti Maurizio , Boggioni Laura , Conzatti Lucia , Tritto Incoronata 
Published: December 2008

AbstractHeterogeneous‐layered silicate‐immobilized 2,6‐bis(imino)pyridyl iron (II) dichloride/MMAO catalysts, in which the active polymerization species are intercalated within sodium‐ and organomodified‐layered silicate galleries, were prepared for producing hybrid exfoliated polyethylene (PE) nanocomposites by means of in situ polymerization. The inorganic filler was first treated with modified‐methylaluminoxane (MMAO) to produce a supported cocatalyst: MMAO reacts with silicates replacing most of the organic surfactant, thus modifying the original crystallographic clay order. MMAO anchored to the nanoclay was able to activate polymerization iron complexes initiating the polymer growth directly from the filler lamellae interlayer. The polymerization mechanism taking place in between the montmorillonite lamellae separates the layers, thus promoting deagglomeration and effective clay dispersion. Transmission electron microscopy revealed that in situ polymerization by catalytically active iron complexes intercalated within the lower organomodified clay led to fine dispersion and high exfoliation extent. The intercalated clay catalysts displayed a longer polymerization life‐time and brought about ethylene polymerization more efficiently than analogous homogeneous systems. PEs having higher molecular masses were obtained. These benefits resulted to be dependent more on the filler nature than on the ligand environment around the iron metal center and the experimental synthetic route. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 548–564, 2009
Prediction of 3D metal binding sites from translated gene sequences based on remote‐homology templates
Authors: Levy Ronen , Edelman Marvin , Sobolev Vladimir 
Published: December 2008

AbstractDatabase‐scale analysis was performed to determine whether structural models, based on remote homologues, are effective in predicting 3D transition metal binding sites in proteins directly from translated gene sequences. The extent by which side chain modeling alone reduces sensitivity and selectivity is shown to be <10%. Surprisingly, selectivity was not dependent on the level of sequence homology between template and target, or on the presence of a metal ion in the structural template. Applying a modification of the CHED algorithm (Babor et al., Proteins 2008;70:208–217) and machine learning filters, a selectivity of ∼90% was achieved for protein sequences using unrelated structural templates over a sequence identity range of 18–100%. Below ∼18% identity, the number of analyzable target‐template pairs and predictability of metal binding sites falls off sharply. A full third of structural templates were found to have target partners only in the remote homology range of 18–30%. In this range, nonmetal‐binding templates are calculated to be the majority and serve to predict with 50% sensitivity at the geometric level. Overall, sensitivity at the geometric level for targets having templates in the 18–30% sequence identity range is 73%, with an average of one false positive site per true site. Protein sequences described as “unknown” in the UniProt database and composed largely of unidentified genome project sequences were studied and metal binding sites predicted. A web server for prediction of metal binding sites from protein sequence is provided. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Prediction of optimal CO2 emitter capacity developed for modified atmosphere packaging of fresh salmon fillets (Salmo salar L.)
Authors: Hansen Anlaug Ådland , Høy Martin , Pettersen Marit Kvalvåg 
Published: December 2008

AbstractPieces of pre‐rigor filleted Atlantic salmon were modified atmosphere (MA)‐packaged (60% CO2 and 40% N2) in eight different ways according to tray sizes (ml), gas/product ratios (g/p ratios), number of fillet layers and capacities of the CO2 emitters being used (based on the fish weight or on the surface area of the fish). All the samples were stored at 2°C for 21 days.Gas measurement showed that the CO2 emitter based on fish weight developed too much CO2, and the emitters based on surface area developed too less during storage. Samples with the lowest CO2 level in the headspace (emitter based on surface area), and also probably the lowest amount of absorbed CO2, had the highest bacterial growth after 17 days of storage for some of the samples. Both the pH and the bacterial growth were similar between the top layer and the bottom layer within the packages of more than one layer in each tray. This indicates that the CO2 was also available for the bottom layers. The liquid loss was similar for the trays with the different emitter types, but it differed between the tray sizes.A model based on the weight and surface area of the fish, and g/p ratio and capacity (ml) of the tray was made in order to more precisely calculate an optimal amount of the CO2 emitter ingredients because of a predefined CO2 level in the headspace. Copyright © 2008 John Wiley & Sons, Ltd.