bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advantages of Odd Random Phase Multisine Electrochemical Impedance Measurements
Authors: Van Ingelgem Yves , Tourwé Els , Blajiev Orlin , Pintelon Rik , Hubin Annick 
Published: January 2009

AbstractElectrochemical impedance spectroscopy (EIS) is a powerful technique to study electrochemical processes and to perform screening tasks. Recently an integrated measuring and modeling methodology for EIS based on a multisine excitation signal was developed. A key issue in this methodology is the data analysis, allowing us to rapidly quantify the reliability of the measured data. In this paper, a comparison is made between classical single‐sine and the proposed multisine measurements on the same system. The fitting of the impedance data obtained by single‐or multisine excitation and using different weighting factors is also discussed. In addition to the advantages reported in earlier work, it is concluded that, of all investigated frequencies, the odd random phase multisine excitation yields the highest quality data in the shortest measurement time.
Adsorptive Stripping Voltammetric Detection of Tea Polyphenols at Multiwalled Carbon Nanotubes‐Chitosan Composite Electrode
Authors: Guo Deyin , Zheng Dan , Mo Guangquan , Ye Jianshan 
Published: January 2009

AbstractThis study reports the catalytic oxidation and detection of tea polyphenols (TPs) at glassy‐carbon electrode modified with multiwalled carbon nanotubes‐chitosan (MWCNTs‐CS) film. The adsorption of TPs at the surface of the MWCNTs through π–π conjugation prevents the aggregation of nanotubes and induces a stable MWCNTs suspension in water over 30 days. Based on the adsorptive accumulation of polyphenols at MWCNTs, TPs is sensitively and selectively detected by adsorptive stripping voltammetry. The accumulation conditions and pH effect on the adsorptive stripping detection were examined. The linear range was found to be 100 to 1000 mg L−1 with a detection limit of 10 mg L−1 (S/N=3) for 2.5 min accumulation. Additionally, the MWCNTs‐CS electrode is easily renewed by applying positive potential to remove the adsorbed TPs. This method was successfully applied to determine TPs in commercially available teas with satisfied result compared with that of conventional spectrometric analysis.
Determination of Theophylline at a Cysteic Acid Modified Glassy Carbon Electrode
Authors: Brunetti Barbara , Desimoni Elio 
Published: January 2009

AbstractA glassy carbon electrode modified with electrodeposited cysteic acid is proposed for the determination of theophylline. Estimation of the linear range, calibration function and limit of detection, as well as determination in real samples such as medication tablets were performed.
Electrochemical Characterization of Horse Spleen Ferritin Covalently Immobilized on Self‐Assembled Monolayer Modified Gold Electrodes
Authors: Casella Sean S. , Ritzert Nicole L. , Zapien Donald C. 
Published: January 2009

AbstractHorse spleen ferritin was covalently attached to SAM‐modified gold electrodes using cross‐linking agents. Reduction of ferritin occurs at negative potentials and is electrochemically irreversible. The voltammetry reveals the presence of a new electrochemical couple that has been determined to be a dissolved iron species released upon the reduction of ferritin. Covalently attached ferritin retains its ability to release iron as evidenced by the absence of the dissolved couple peaks when ferritin is reduced in the presence of nitrilotriacetate. As the SAM chain length increases, the reduction potential becomes more negative, suggesting a tunneling mechanism is involved in the electron transfer.
Automated 3D mapping of hippocampal atrophy and its clinical correlates in 400 subjects with Alzheimer's disease, mild cognitive impairment, and elderly controls
Authors: Morra Jonathan H. , Tu Zhuowen , Apostolova Liana G. , Green Amity E. , Avedissian Christina , Madsen Sarah K. , Parikshak Neelroop , Hua Xue , Toga Arthur W. , Jack Clifford R. , Schuff Norbert , Weiner Michael W. , Thompson Paul M. 
Published: January 2009

AbstractWe used a new method we developed for automated hippocampal segmentation, called the auto context model, to analyze brain MRI scans of 400 subjects from the Alzheimer's disease neuroimaging initiative. After training the classifier on 21 hand‐labeled expert segmentations, we created binary maps of the hippocampus for three age‐ and sex‐matched groups: 100 subjects with Alzheimer's disease (AD), 200 with mild cognitive impairment (MCI) and 100 elderly controls (mean age: 75.84; SD: 6.64). Hippocampal traces were converted to parametric surface meshes and a radial atrophy mapping technique was used to compute average surface models and local statistics of atrophy. Surface‐based statistical maps visualized links between regional atrophy and diagnosis (MCI versus controls:P= 0.008; MCI versus AD:P= 0.001), mini‐mental state exam (MMSE) scores, and global and sum‐of‐boxes clinical dementia rating scores (CDR; allP< 0.0001, corrected). Right but not left hippocampal atrophy was associated with geriatric depression scores (P= 0.004, corrected); hippocampal atrophy was not associated with subsequent decline in MMSE and CDR scores, educational level, ApoE genotype, systolic or diastolic blood pressure measures, or homocysteine. We gradually reduced sample sizes and used false discovery rate curves to examine the method's power to detect associations with diagnosis and cognition in smaller samples. Forty subjects were sufficient to discriminate AD from normal and correlate atrophy with CDR scores; 104, 200, and 304 subjects, respectively, were required to correlate MMSE with atrophy, to distinguish MCI from normal, and MCI from AD. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Functional brain areas associated with manipulation of a prehensile tool: A PET study
Authors: Tsuda Hayato , Aoki Tomoko , Oku Naohiko , Kimura Yasuyuki , Hatazawa Jun , Kinoshita Hiroshi 
Published: January 2009

AbstractUsing PET, brain areas representing the use of a well‐learned tool (chopsticks) were investigated in 10 normal common users. The experimental task was to hold the tool in their right hand and use it to pick up and transport a small pin from a table. Data for the same task performed using only the fingers were also obtained as a control. The results showed an extensive overlap in activated areas with and without the use of the tool. The tool‐use prehension, compared to the finger prehension, was associated with higher activities in the caudal‐ventral premotor, dorsal premotor, superior parietal, posterior intraparietal, middle temporal gyrus, and primary sensory, occipital cortices, and the cerebellum. These are thus considered to be the human cortical and subcortical substrates representing the use of the tool studied. The activity of the posterior intraparietal area was negatively correlated with the number of drops of the pin, whereas occipital activity was positively correlated with the same error parameter. The caudal‐ventral premotor and posterior intraparietal areas are together known to be involved in tool use‐related modulation in peripersonal space. The correlation results suggest that this modulation depends on the level of performance. The coactivated left middle temporal gyrus further suggests that familiarity with a tool as well as the knowledge about its usage plays a role in peripersonal space modulation. Superior parietal activation, along with occipital activation, indicates the involvement of visual‐spatial attention in the tool use, possibly reflecting the effect of interaction between the prehension (task) and the tool. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Coordinate‐based activation likelihood estimation meta‐analysis of neuroimaging data: A random‐effects approach based on empirical estimates of spatial uncertainty
Authors: Eickhoff Simon B. , Laird Angela R. , Grefkes Christian , Wang Ling E. , Zilles Karl , Fox Peter T. 
Published: January 2009

AbstractA widely used technique for coordinate‐based meta‐analyses of neuroimaging data is activation likelihood estimation (ALE). ALE assesses the overlap between foci based on modeling them as probability distributions centered at the respective coordinates. In this Human Brain Project/Neuroinformatics research, the authors present a revised ALE algorithm addressing drawbacks associated with former implementations. The first change pertains to the size of the probability distributions, which had to be specified by the used. To provide a more principled solution, the authors analyzed fMRI data of 21 subjects, each normalized into MNI space using nine different approaches. This analysis provided quantitative estimates of between‐subject and between‐template variability for 16 functionally defined regions, which were then used to explicitly model the spatial uncertainty associated with each reported coordinate. Secondly, instead of testing for an above‐chance clustering between foci, the revised algorithm assesses above‐chance clustering between experiments. The spatial relationship between foci in a given experiment is now assumed to be fixed and ALE results are assessed against a null‐distribution of random spatial association between experiments. Critically, this modification entails a change from fixed‐ to random‐effects inference in ALE analysis allowing generalization of the results to the entire population of studies analyzed. By comparative analysis of real and simulated data, the authors showed that the revised ALE‐algorithm overcomes conceptual problems of former meta‐analyses and increases the specificity of the ensuing results without loosing the sensitivity of the original approach. It may thus provide a methodologically improved tool for coordinate‐based meta‐analyses on functional imaging data. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Separating function from structure in perfusion imaging of the aging brain
Authors: Asllani Iris , Habeck Christian , Borogovac Ajna , Brown Truman R. , Brickman Adam M. , Stern Yaakov 
Published: January 2009

AbstractThe accuracy of cerebral blood flow (CBF) imaging in humans has been impeded by the partial volume effects (PVE), which are a consequence of the limited spatial resolution. Because of brain atrophy, PVE can be particularly problematic in imaging the elderly and can considerably overestimate the CBF difference with the young. The primary goal of this study was to separate the structural decline from the true CBF reduction in elderly. To this end, a PVE‐correction algorithm was applied on the CBF images acquired with spin‐echo EPI continuous arterial spin labeling MRI (voxel size = 3.4 × 3.4 × 8 mm3). Tissue‐specific CBF images that were independent of voxels' tissue fractional volume were obtained in elderly (N = 30) and young (N = 26); mean age difference was 43 years. Globally, PVE‐corrected gray matter CBF was 88.2 ± 16.1 and 107.3 ± 17.5 mL/100 g min−1 in elderly and young, respectively. The largest PVE contribution was found in the frontal lobe and accounted for an additional 10% and 12% increase in the age‐related CBF difference between men and women, respectively. The GM‐to‐WM CBF ratios were found to be on average 3.5 in elderly and 3.9 in young. Whole brain voxelwise comparisons showed marked CBF decrease in anterior cingulate (bilateral), caudate (bilateral), cingulate gyrus (bilateral), cuneus (left), inferior frontal gyrus (left), insula (left), middle frontal gyrus (left), precuneus (bilateral), prefrontal cortex (bilateral), and superior frontal gyrus (bilateral) in men and amygdala (bilateral), hypothalamus (left), hippocampus (bilateral), and middle frontal gyrus (right) in women. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
The free choice whether or not to respond after stimulus presentation
Authors: Karch Susanne , Mulert Christoph , Thalmeier Tobias , Lutz Jürgen , Leicht Gregor , Meindl Thomas , Möller Hans‐Jürgen , Jäger Lorenz , Pogarell Oliver 
Published: January 2009

AbstractThe concept of ‘willed’ actions has attracted attention during the last few years. Free choices have been associated with activations on the medial frontal surface, the dorsolateral prefrontal cortex and the parietal lobe. Self‐paced movements and free selection between various motor responses were typically used to investigate voluntary behavior. The aim of the present study was to determine neural correlates of voluntary motor responses and the voluntary inhibition of motor responses in a group of healthy subjects. Hence, a go/nogo/voluntary selection paradigm was used. In the voluntary selection condition subjects decided freely whether or not to respond with a button press after stimulus presentation. Functional MRI data and event‐related potentials were acquired simultaneously in order to reliably investigate spatial and temporal characteristics of these responses. The results showed decision‐related enhanced neural responses predominantly in the medial frontal gyrus/supplementary motor area, lateral frontal brain regions and the inferior parietal gyrus. Additional activations associated with voluntary movements were detected in the frontal eye field as well as brain regions directly linked to motor responses (e.g. somatosensory cortical areas). Altogether, decision processes were shown to be relatively independent of the kind of response chosen. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
A multiparametric evaluation of regional brain damage in patients with primary progressive multiple sclerosis
Authors: Ceccarelli Antonia , Rocca Maria A. , Valsasina Paola , Rodegher Mariaemma , Pagani Elisabetta , Falini Andrea , Comi Giancarlo , Filippi Massimo 
Published: January 2009

AbstractThe purpose of this study is to define the topographical distribution of gray matter (GM) and white matter (WM) damage in patients with primary progressive multiple sclerosis (PPMS), using a multiparametric MR‐based approach. Using a 3 Tesla scanner, dual‐echo, 3D fast‐field echo (FFE), and diffusion tensor (DT) MRI scans were acquired from 18 PPMS patients and 17 matched healthy volunteers. An optimized voxel‐based (VB) analysis was used to investigate the patterns of regional GM density changes and to quantify GM and WM diffusivity alterations of the entire brain. In PPMS patients, GM atrophy was found in the thalami and the right insula, while mean diffusivity (MD) changes involved several cortical‐subcortical structures in all cerebral lobes and the cerebellum. An overlap between decreased WM fractional anisotropy (FA) and increased WM MD was found in the corpus callosum, the cingulate gyrus, the left short temporal fibers, the right short frontal fibers, the optic radiations, and the middle cerebellar peduncles. Selective MD increase, not associated with FA decrease, was found in the internal capsules, the corticospinal tracts, the superior longitudinal fasciculi, the fronto‐occipital fasciculi, and the right cerebral peduncle. A discrepancy was found between regional WM diffusivity changes and focal lesions because several areas had DT MRI abnormalities but did not harbor T2‐visible lesions. Our study allowed to detect tissue damage in brain areas associated with motor and cognitive functions, which are known to be impaired in PPMS patients. Combining regional measures derived from different MR modalities may be a valuable tool to improve our understanding of PPMS pathophysiology. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Syllable congruency and word frequency effects on brain activation
Authors: Carreiras Manuel , Riba Jordi , Vergara Marta , Heldmann Marcus , Münte Thomas F. 
Published: January 2009

AbstractThis article investigates the neural representation of the processes involved in recognizing multisyllabic words in Spanish asking whether lexical and sublexical processes are reflected in a different neuronal activation pattern. High and low frequency words were presented for lexical decision in two different colors. In the congruent condition the color boundaries matched the limit of the first syllable, whereas in the incongruent condition color boundaries and syllable boundaries did not match. The results revealed robust and dissociable brain activations for lexical frequency and syllable‐color congruency, but no interaction between the two. We interpreted the greater activation for low relative to high frequency words in the left pre/SMA region, and in the insula/inferior frontal cortex bilaterally to reflect a differential recruitment of lexico‐phonological and/or semantic processes. In contrast, we considered two interpretations for the greater deactivation in the precuneus for both lexical frequency and syllable‐color congruency words, and in the thalami and a frontal area for syllable‐color congruency words only. The deactivations may reflect the differential engagement of semantic processing or may result from the differential allocation of attentional resources. Importantly, while a differential deactivation pattern was observed in the precuneus region for lexicality and syllable‐color congruency, BOLD deconvolution revealed a remarkable difference in timing of the two effects with a much earlier deactivation peak for the syllable‐color congruency factor. Thus, effects of lexical frequency and syllable‐color congruency on brain activation show an important dissociation between lexical and sublexical processes during visual word recognition of multisyllabic words. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Water management and user association analysis for irrigation improvement in Egypt
Authors: Batt Hussein Aly , Merkley Gary P. 
Published: January 2009

AbstractA participatory irrigation management policy has been adopted by the Egyptian Ministry of Water Resources and Irrigation over the past two decades to support agricultural productivity, decrease open‐channel conveyance losses, and increase agricultural water distribution equity. Two recent projects that dealt with the introduction of this policy in the Nile Delta through improvement projects are the irrigation improvement project (IIP) by the Japan International Cooperation Agency (JICA) in Bahr El‐Nor, and the integrated water management districts (IWMDs) by the United States Agency for International Development (USAID) in El‐Ibrahimia. The implementation of these projects and their associated policies promoted the evolution and sustainability of these policies.An analysis of case studies for these projects, taking into account four dimensions of improvement and sustainability, shows that farmers were reluctant to accept the policies because they lacked training on various irrigation system improvement techniques, as introduced through the projects. Thus, the current focus should be on the reform of irrigation system improvement policies so that they are more realistic, and ultimately more successful, supporting agriculture and encouraging Ministry personnel to adopt and support participatory water management as implemented in the targeted Egyptian irrigation projects. Copyright © 2009 John Wiley & Sons, Ltd.
The potential for histological screening using a combination of rapid Raman mapping and principal component analysis
Authors: Hutchings Joanne , Kendall Catherine , Smith Brian , Shepherd Neil , Barr Hugh , Stone Nicholas 
Published: January 2009

AbstractRapid Raman mapping was carried out on 20 μm sections of oesophageal biopsy samples. Contiguous 7 μm sections were stained with haematoxylin and eosin (H&E) with histopathology provided by an expert pathologist. The step size and acquisition times were varied and the resulting spectra, principal component (PC) score maps and loads were compared. Overall mapping times were also compared to traditional Raman point mapping. The principal component loads for each of the maps were seen to be similar despite varying the acquisition time and number of spectra. Gross biochemical information was extracted showing good correlation with the H&E sections even for short overall mapping times (30–90 minutes for a 2 mm biopsy, 0.5 s acquisition time per 25.3 μm Raman pixel). This demonstrates that low signal to noise spectral maps are sufficient for the identification of histologically relevant biochemistry using principal component analysis as long as the spectral dataset is large enough. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Screening biomaterials for functional complement activation in serum
Authors: Lyle Daniel B. , Bushar Grace S. , Langone John J. 
Published: January 2009

AbstractComplement plays an important role in the immune attack against invading microorganisms. However, blood‐contacting medical device biomaterials lacking specific complement inhibitors, with free hydroxyl and/or amino groups, or with absorbed antibodies, may inappropriately activate complement. Inappropriate activation by either the antibody‐mediated classical or the antibody‐independent alternative pathway may have well‐known acute or poorly understood chronic effects on the host or device. This article describes methods for screening biomaterials for functional whole complement activation using normal human serum, or specifically for alternative pathway activation using C4‐deficient guinea pig serum, or for classical pathway activation using both sera in combination. Detailed protocols are available as standard methodologies from the American Society for Testing and Materials (ASTM F1984, ASTM F2065, and ASTM F2567). Results obtained with these functional tests are confirmed by detection of classical and alternative pathway‐specific markers C4d and Bb, respectively. These methods demonstrate dose and time‐course activation of complement to beaded agarose, cellulose acetate, and purified alginate as examples of biomaterials. Significant difference in a functional endpoint denoting specific complement pathways is an appropriate screening method for complement activation by medical device biomaterials which might result in adverse events when the device is implanted or contacts human blood. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Bioactivating electrically conducting polypyrrole with fibronectin and bovine serum albumin
Authors: Akkouch Adil , Shi Guixin , Zhang Ze , Rouabhia Mahmoud 
Published: January 2009

AbstractElectrically conducting polypyrrole (PPy) and its composite materials are useful in interfacing electrical components and cells or living tissue. In recent years, significant efforts have been made to bioactivate PPy by incorporating biomolecules. The main objective of this work was to chemically bioactivate PPy particules by incorporating fibronectin (FN) and bovine serum albumin (BSA). Modified PPy particles were synthesized through a water‐in‐oil emulsion polymerization. XPS and FTIR confirmed the presence of biomolecules on the PPy particles, and the surface morphology was observed by SEM. A four‐point probe was used to measure the conductivity of the newly synthesized PPy particles, which was in the range of 10−1 S cm−1. Conductive biodegradable membranes were prepared with 5 and 10% (wt/wt) PPy to poly(L,L‐lactide) (PPy/PLLA). The contact angles of each synthesized membrane were ∼75°, supporting their usefulness for cell culture. The cultured human skin fibroblasts demonstrated normal morphology and significantly higher adhesion and spreading on the PPy/PLLA∼FN membrane than on the unmodified PPy/PLLA membrane. On the other hand, the PPy/PLLA∼BSA membranes showed decreased cell adhesion. Bioactivated PPy may be useful in tissue engineering to fabricate conducting biodegradable scaffolds with either improved or reduced cell adhesion properties for various cell culture and in vivo applications. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010