bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface functionalization of polypropylene by entrapment of polypropylene‐grafted‐poly(ethylene glycol)
Authors: Chen Hanjia , Shi Xuhua , Zhu Yafei , Zhang Yi , Xu Jiarui 
Published: July 2009

AbstractA surface functionalization polypropylene was prepared by entrapment a copolymer of polypropylene‐grafted‐poly(ethylene glycol) into polypropylene. The effects of structure of copolymer, contact dies, and content of modifiers were studied. The results of attenuated total reflection infrared spectroscopy(ATR‐FTIR) and contact angle measurements indicated that PP‐g‐PEG could preferably diffuse onto the surface and effectively increase the hydrophilicity of PP. PPw‐g‐PEG with lower PEG contents, lower molecular weight of PPw and PEG had better selective enrichment on the surface of PP blend film. By grafting of PEG‐OH onto the MPP, PP macromolecular surface modifier with better solvent‐resistance than that of PEG can be achieved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Plant cell calcium‐rich environment enhances thermostability of recombinantly produced α‐amylase from the hyperthermophilic bacterium Thermotoga maritime
Authors: Santa‐Maria Monica C. , Chou Chung‐Jung , Yencho G. Craig , Haigler Candace H. , Thompson William F. , Kelly Robert M. , Sosinski Bryon 
Published: July 2009

AbstractIn the industrial processing of starch for sugar syrup and ethanol production, a liquefaction step is involved where starch is initially solubilized at high temperature and partially hydrolyzed with a thermostable and thermoactive α‐amylase. Most amylases require calcium as a cofactor for their activity and stability, therefore calcium, along with the thermostable enzyme, are typically added to the starch mixture during enzymatic liquefaction, thereby increasing process costs. An attractive alternative would be to produce the enzyme directly in the tissue to be treated. In a proof of concept study, tobacco cell cultures were used as model system to test in planta production of a hyperthermophilic α‐amylase from Thermotoga maritima. While comparable biochemical properties to recombinant production in Escherichia coli were observed, thermostability of the plant‐produced α‐amylase benefited significantly from high intrinsic calcium levels in the tobacco cells. The plant‐made enzyme retained 85% of its initial activity after 3 h incubation at 100°C, whereas the E. coli‐produced enzyme was completely inactivated after 30 min under the same conditions. The addition of Ca2+ or plant cell extracts from tobacco and sweetpotato to the E. coli‐produced enzyme resulted in a similar stabilization, demonstrating the importance of a calcium‐rich environment for thermostability, as well as the advantage of producing this enzyme directly in plant cells where calcium is readily available. Biotechnol. Bioeng. 2009; 104: 947–956. © 2009 Wiley Periodicals, Inc.
Impedance spectroscopy as a tool for non‐intrusive detection of extracellular mediators in microbial fuel cells
Authors: Ramasamy Ramaraja P. , Gadhamshetty Venkataramana , Nadeau Lloyd J. , Johnson Glenn R. 
Published: July 2009

AbstractEndogenously produced, diffusible redox mediators can act as electron shuttles for bacterial respiration. Accordingly, the mediators also serve a critical role in microbial fuel cells (MFCs), as they assist extracellular electron transfer from the bacteria to the anode serving as the intermediate electron sink. Electrochemical impedance spectroscopy (EIS) may be a valuable tool for evaluating the role of mediators in an operating MFC. EIS offers distinct advantages over some conventional analytical methods for the investigation of MFC systems because EIS can elucidate the electrochemical properties of various charge transfer processes in the bio‐energetic pathway. Preliminary investigations of Shewanella oneidensis DSP10‐based MFCs revealved that even low quantities of extracellular mediators significantly influence the impedance behavior of MFCs. EIS results also suggested that for the model MFC studied, electron transfer from the mediator to the anode may be up to 15 times faster than the electron transfer from bacteria to the mediator. When a simple carbonate membrane separated the anode and cathode chambers, the extracellular mediators were also detected at the cathode, indicating diffusion from the anode under open circuit conditions. The findings demonstrated that EIS can be used as a tool to indicate presence of extracellular redox mediators produced by microorganisms and their participation in extracellular electron shuttling. Biotechnol. Bioeng. 2009; 104: 882–891. © 2009 Wiley Periodicals, Inc.
Thinking about flagellar oscillation
Authors: Brokaw Charles J. 
Published: July 2009

AbstractBending of cilia and flagella results from sliding between the microtubular outer doublets, driven by dynein motor enzymes. This review reminds us that many questions remain to be answered before we can understand how dynein‐driven sliding causes the oscillatory bending of cilia and flagella. Does oscillation require switching between two distinct, persistent modes of dynein activity? Only one mode, an active forward mode, has been characterized, but an alternative mode, either inactive or reverse, appears to be required. Does switching between modes use information from curvature, sliding direction, or both? Is there a mechanism for reciprocal inhibition? Can a localized capability for oscillatory sliding become self‐organized to produce the metachronal phase differences required for bend propagation? Are interactions between adjacent dyneins important for regulation of oscillation and bend propagation? Cell Motil. Cytoskeleton 2008. © 2008 Wiley‐Liss, Inc.
Singlet Oxygen Production upon Two‐Photon Excitation of TiO2 in Chloroform
Authors: Li Wenbing , Gandra Naveen , Courtney Shavelle N. , Gao Ruomei 
Published: July 2009

AbstractSinglet oxygen (1O2) signals observed upon illumination at 532 nm are a consequence of TiO2 excitation in a two‐photon process, and at 355 nm in a one‐photon pathway. After corrections for light reflectance, the relative quantum yields of 1O2 production are 0.23±0.01 and 0.22±0.02 for 532 and 355 nm excitation, respectively. Total quenching rate constants of 1O2 removal by TiO2 particles are near the diffusion‐controlled rate limit. By employing 1O2 as a probe, we have established an efficient and simple method to elucidate the nature of TiO2 photoexcitation.
Progressive collapse analysis through strength degradation and fracture in the Mixed Lagrangian Formulation
Authors: Lavan O. , Sivaselvan M. V. , Reinhorn A. M. , Dargush G. F. 
Published: July 2009

AbstractThe dynamic analysis of progressive collapse faces a great number of obstacles that often lead to the collapse of the analysis prior to the actual analysis of collapse. Hence, the Mixed Lagrangian Formulation that has been shown to be very robust was adopted as a framework to accommodate such analysis. By modifying the loading function and the numerical scheme, the capabilities of this framework were extended to account for strength degradation and fracture, while some insight to its behavior is introduced as well. The examples presented show a very robust and stable behavior of the numerical scheme in terms of the time step size required, even in cases where a sudden fracture takes place. Copyright © 2009 John Wiley & Sons, Ltd.
Behavior of combined fly ash/slag‐based geopolymers when exposed to high temperatures
Authors: Guerrieri Maurice , Sanjayan Jay G. 
Published: July 2009

AbstractThe high temperature performance up to 800∘C of combined fly ash (FA) and slag geopolymers at the ratio of 100, 65/35, 50/50, 35/65 and 100% (wt‐%) is presented in this paper. Geopolymers are alternative novel binders to conventional Portland cement and are generally believed to provide superior fire resistant properties due to their ceramic‐like characteristics. This paper presents new data on the behavior of geopolymers made with combined FA/slag mentioned previously, which were mixed with alkaline materials with molecular silicate modulus (Ms=SiO2/Na2O) of 0, 0.5, 1.0, 1.5 and 2.0 with sodium (Na) dosages of 4 and 8 (wt‐%). Altogether 60 mixes were made yielding compressive strengths between 3 and 83 MPa. Behavior of the material to high temperatures was investigated by exposing the specimens to 800∘C and testing for compressive strengths. It was found that as the initial strength increases, the residual strength exponentially decreased. The compressive stress versus strain relationships showed that the ductility of the specimens decreased as the initial strength increased. The ability of the materials with high ductility (i.e. less brittleness) to accommodate thermal incompatibilities arising from uneven temperatures arising during heating is concluded to be the major factor contributing to the reduced strength losses. Copyright © 2009 John Wiley & Sons, Ltd.
Process regime change on a Silurian siliciclastic shelf: controlling influences on deposition of the Gray Sandstone Formation, Pembrokeshire, UK
Authors: Hillier Robert D. , Morrissey Lance B. 
Published: July 2009

AbstractShallow marine deposits comprising the Silurian Gray Sandstone Formation (GSF) exhibit pronounced process regime changes through time. The formation was deposited on the southern shelf of the Lower Palaeozoic Welsh Basin (UK), and conformably overlies the Coralliferous Formation. The basal Lithofacies Assemblage A (of Sheinwoodian age) is dominated by a storm‐dominated process regime, comprising shoreface and offshore shelf facies associations. The overlying Lithofacies Assemblage B records a mixed process regime, with units being deposited under both storm‐ and tide‐influenced conditions. Tidal‐influence prevailed during deposition of the overlying Lithofacies Assemblage C, with proximal to distal facies variations across a significant tide‐influenced river delta being observed. A return to storm‐dominated shoreface conditions is seen in the succeeding Lithofacies Assemblage D. Lithofacies Assemblage E (Homerian age) records the return of a tide‐influenced river delta to the area, prior to the conformable transition into the overlying Old Red Sandstone (ORS) Red Cliff Formation (of Ludlow age). Northward thickening of the formation across southern Pembrokeshire into the Musselwick Fault indicates a tectonic control on sedimentation, the formation infilling accommodation space developed in an intra‐shelf half‐graben. Recurring changes in process regime from storm‐ to tide‐influenced sedimentation may be related to the onset and subsequent cessation of tidal resonance in sub‐basins across the shelf area which itself was probably controlled by episodic tectonism. It is proposed that the Coralliferous and Gray Sandstone formations comprise the newly erected Marloes Group. Copyright © 2009 John Wiley & Sons, Ltd.
Changes in the interaction of resting‐state neural networks from adolescence to adulthood
Authors: Stevens Michael C. , Pearlson Godfrey D. , Calhoun Vince D. 
Published: July 2009

AbstractThis study examined how the mutual interactions of functionally integrated neural networks during resting‐state fMRI differed between adolescence and adulthood. Independent component analysis (ICA) was used to identify functionally connected neural networks in 100 healthy participants aged 12–30 years. Hemodynamic timecourses that represented integrated neural network activity were analyzed with tools that quantified system “causal density” estimates, which indexed the proportion of significant Granger causality relationships among system nodes. Mutual influences among networks decreased with age, likely reflecting stronger within‐network connectivity and more efficient between‐network influences with greater development. Supplemental tests showed that this normative age‐related reduction in causal density was accompanied by fewer significant connections to and from each network, regional increases in the strength of functional integration within networks, and age‐related reductions in the strength of numerous specific system interactions. The latter included paths between lateral prefrontal‐parietal circuits and “default mode” networks. These results contribute to an emerging understanding that activity in widely distributed networks thought to underlie complex cognition influences activity in other networks. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Differential force scaling of fine‐graded power grip force in the sensorimotor network
Authors: Keisker Birgit , Hepp‐Reymond Marie‐Claude , Blickenstorfer Armin , Meyer Martin , Kollias Spyros S. 
Published: July 2009

AbstractForce scaling in the sensorimotor network during generation and control of static or dynamic grip force has been the subject of many investigations in monkeys and human subjects. In human, the relationship between BOLD signal in cortical and subcortical regions and force still remains controversial. With respect to grip force, the modulation of the BOLD signal has been mostly studied for forces often reaching high levels while little attention has been given to the low range for which electrophysiological neuronal correlates have been demonstrated. We thus conducted a whole‐brain fMRI study on the control of fine‐graded force in the low range, using a power grip and three force conditions in a block design. Participants generated on a dynamometer visually guided repetitive force pulses (ca. 0.5 Hz), reaching target forces of 10%, 20%, and 30% of maximum voluntary contraction. Regions of interest analysis disclosed activation in the entire cortical and subcortical sensorimotor network and significant force‐related modulation in several regions, including primary motor (M1) and somatosensory cortex, ventral premotor and inferior parietal areas, and cerebellum. The BOLD signal, however, increased monotonically with force only in contralateral M1 and ipsilateral anterior cerebellum. The remaining regions were activated with force in various nonlinear manners, suggesting that other factors such as visual input, attention, and muscle recruitment also modulate the BOLD signal in this visuomotor task. These findings demonstrate that various regions of the sensorimotor network participate differentially in the production and control of fine‐graded grip forces. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Diminished neural sensitivity to irregular facial expression in first‐episode schizophrenia
Authors: Bleich‐Cohen Maya , Strous Rael D. , Even Raz , Rotshtein Pia , Yovel Galit , Iancu Iulian , Olmer Ahikam , Hendler Talma 
Published: July 2009

AbstractIntroduction: Blunted, inappropriate affective‐social behavior is a hallmark of early schizophrenia, possibly corresponding to reduced ability to recognize and express emotions. It is yet unknown if this affective deficiency relates to disturbed neural sensitivity to facial expressions or to overall face processing. In a previous imaging study, healthy subjects showed less suppression of the fusiform gyrus (FG) to repeated presentation of the same transfigured‐bizarre face relative to regular face. We assumed that the FG in schizophrenia will show reduced repetition related sensitivity to transfigured‐bizarre faces, while having overall normal response to faces. Methods: Ten first‐episode patients with schizophrenia and 10 controls rated the bizarreness of upright and inverted faces. In an fMRI study, another group of 17 first‐episode patients with schizophrenia and 12 controls viewed regular and transfigured‐bizarre faces in blocks. Each block contained regular‐ or transfigured‐bizarre faces of either different or same individual, presented in an upright or inverted orientation. Results: Patients in comparison with controls rated irregular faces as less bizarre. The FG, in patients and controls exhibited similar response to inverted faces, suggesting normal face processing. In contrast, the FG only in patients, showed similar suppression to repeated transfigured‐bizarre and regular faces. Finally, the FG in patients compared with controls showed reduced functional connectivity with the amygdala and prefrontal cortex. Conclusion: Patients with schizophrenia already at first‐episode, showed reduced behavioral and neural sensitivity to bizarre facial expressions. Possibly, this deficiency is related to disturbed modulations of emotion‐related face processing in the FG by the amygdala and prefrontal cortex. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Activated region fitting: A robust high‐power method for fMRI analysis using parameterized regions of activation
Authors: Weeda Wouter D. , Waldorp Lourens J. , Christoffels Ingrid , Huizenga Hilde M. 
Published: July 2009

AbstractAn important issue in the analysis of fMRI is how to account for the spatial smoothness of activated regions. In this article a method is proposed to accomplish this by modeling activated regions with Gaussian shapes. Hypothesis tests on the location, spatial extent, and amplitude of these regions are performed instead of hypothesis tests of individual voxels. This increases power and eases interpretation. Simulation studies show robust hypothesis tests under misspecification of the shape model, and increased power over standard techniques especially at low signal‐to‐noise ratios. An application to real single‐subject data also indicates that the method has increased power over standard methods. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Volume and iron content in basal ganglia and thalamus
Authors: Péran Patrice , Cherubini Andrea , Luccichenti Giacomo , Hagberg Gisela , Démonet Jean‐François , Rascol Olivier , Celsis Pierre , Caltagirone Carlo , Spalletta Gianfranco , Sabatini Umberto 
Published: July 2009

AbstractMagnetic resonance imaging (MRI) studies have highlighted the possibility to investigate brain iron content in vivo. In this study, we combined T2* relaxometry and automatic segmentation of basal ganglia based on T1‐weighted images in healthy subjects, with the aim of characterizing age related changes in volume and iron‐related relaxivity values (R2*) of these structures. Thirty healthy subjects underwent MR imaging at 3 Tesla. Mean R2* values and volumes were calculated for the selected subcortical structures (pallidum, putamen, thalamus and caudate nucleus). Our results showed a correlation between R2* values and iron concentration as calculated from published post‐mortem data. Furthermore, we observed a shrinkage/iron increase with a different pattern in the anatomical regions selected in this work, suggesting that the age‐related changes on these MR parameters are specific to the subcortical structure considered. In particular, the putamen demonstrated a decrease of volume and an increase of iron level, with the posterior region of this structure appearing more disposed to iron deposition. Our work suggests that combining volumetry and iron estimation in MRI permits to investigate in vivo neurophysiological and neuropathological changes of basal ganglia. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Effects of different viewing perspectives on somatosensory activations during observation of touch
Authors: Schaefer Michael , Xu Benjamin , Flor Herta , Cohen Leonardo G. 
Published: July 2009

AbstractPrevious studies showed that neurons in the monkey premotor cortex became active when performing a particular action and also when observing the same action performed by others. These findings suggest a mirror system for action observation. Recently, bimodal neurons, sensitive both to visual and tactile stimulation, were reported in the parietal cortex, suggesting a potential mirror neuron system for observing and experiencing tactile stimulation. Subsequently, a mirror neuron system for observed touch has been suggested. The current study was designed to determine whether the activation of a sensory mirror system during touch observation is affected by possible attributions of the observed touch to oneself (subjective view) or to somebody else (objective view). In the study, healthy volunteers observed video clips of a touched or nontouched hand either in an egocentric or in an allocentric perspective during functional magnetic resonance imaging. Results showed activation of somatosensory cortices when observing the hand being touched in egocentric as well as in the allocentric perspectives. Moreover, somatosensory responses differed depending on the perspective of the observed touch. We discuss the results in terms of a possible mirror neuron system for observed and experienced touch. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Exploring the relationship between white matter and gray matter damage in early primary progressive multiple sclerosis: An in vivo study with TBSS and VBM
Authors: Bodini Benedetta , Khaleeli Zhaleh , Cercignani Mara , Miller David H. , Thompson Alan J. , Ciccarelli Olga 
Published: July 2009

AbstractWe investigated the relationship between the damage occurring in the brain normal‐appearing white matter (NAWM) and in the gray matter (GM) in patients with early Primary Progressive multiple sclerosis (PPMS), using Tract‐Based Spatial Statistics (TBSS) and an optimized voxel‐based morphometry (VBM) approach. Thirty‐five patients with early PPMS underwent diffusion tensor and conventional imaging and were clinically assessed. TBSS and VBM were employed to localize regions of lower fractional anisotropy (FA) and lower GM volume in patients compared with controls. Areas of anatomical and quantitative correlation between NAWM and GM damage were detected. Multiple regression analyses were performed to investigate whether NAWM FA or GM volume of regions correlated with clinical scores independently from the other and from age and gender. In patients, we found 11 brain regions that showed an anatomical correspondence between reduced NAWM FA and GM atrophy; of these, four showed a quantitative correlation (i.e., the right sensory motor region with the adjacent corticospinal tract, the left and right thalamus with the corresponding thalamic radiations and the left insula with the adjacent WM). Either the NAWM FA or the GM volume in each of these regions correlated with disability. These results demonstrate a link between the pathological processes occurring in the NAWM and in the GM in PPMS in specific, clinically relevant brain areas. Longitudinal studies will determine whether the GM atrophy precedes or follows the NAWM damage. The methodology that we described may be useful to investigate other neurological disorders affecting both the WM and the GM. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.