bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of transcranial direct current stimulation with visual illusion in neuropathic pain due to spinal cord injury: An evoked potentials and quantitative thermal testing study
Authors: Kumru H. , Soler D. , Vidal J. , Navarro X. , Tormos J.M. , Pascual‐Leone A. , Valls‐Sole J. 
Published: May 2012

AbstractBackgroundNeuropathic pain (NP) is common in spinal cord injury (SCI) patients. One of its manifestations is a lowering of pain perception threshold in quantitative thermal testing (QTT) in dermatomes rostral to the injury level. Transcranial direct current stimulation (tDCS) combined with visual illusion (VI) improves pain in SCI patients. We studied whether pain relief with tDCS + VI intervention is accompanied by a change in contact heat‐ evoked potentials (CHEPs) or in QTT.MethodsWe examined 18 patients with SCI and NP before and after 2 weeks of daily tDCS + VI intervention. Twenty SCI patients without NP and 14 healthy subjects served as controls. We assessed NP intensity using a numerical rating scale (NRS) and determined heat and pain thresholds with thermal probes. CHEPs were recorded to stimuli applied at C4 level, and subjects rated their perception of evoked pain using NRS during CHEPs.ResultsThirteen patients reported a mean decrease of 50% in the NRS for NP after tDCS + VI. Evoked pain perception was significantly higher than in the other two groups, and reduced significantly together with CHEPs amplitude after tDCS + VI with respect to baseline. Pain perception threshold was significantly lower than in the other two groups before tDCS + VI intervention, and increased significantly afterwards.ConclusionTwo weeks of tDCS + VI induced significant changes in CHEPs, evoked pain and heat pain threshold in SCI patients with NP. These neurophysiological tests might be objective biomarkers of treatment effects for NP in patients with SCI.
EFFICIENT AGGREGATION OF PANEL QUALITATIVE SURVEY DATA
Authors: Mitchell James , Smith Richard J. , Weale Martin R. 
Published: May 2012

SUMMARYQualitative business survey data are used widely to provide indicators of economic activity ahead of the publication of official data. Traditional indicators exploit only aggregate survey information, namely the proportions of respondents who report ‘up’ and ‘down’. This paper examines disaggregate or firm‐level survey responses. It considers how the responses of the individual firms should be quantified and combined if the aim is to produce an early indication of official output data. Having linked firms' categorical responses to official data using ordered discrete‐choice models, the paper proposes a statistically efficient means of combining the disparate estimates of aggregate output growth which can be constructed from the responses of individual firms. An application to firm‐level survey data from the Confederation of British Industry shows that the proposed indicator can provide early estimates of output growth more accurately than traditional indicators. Copyright © 2012 John Wiley & Sons, Ltd.
MULTIVARIATE VOLATILITY MODELING OF ELECTRICITY FUTURES
Authors: Bauwens Luc , Hafner Christian M. , Pierret Diane 
Published: May 2012

SUMMARYWe model the dynamic volatility and correlation structure of electricity futures of the European Energy Exchange index. We use a new multiplicative dynamic conditional correlation (mDCC) model to separate long‐run from short‐run components. We allow for smooth changes in the unconditional volatilities and correlations through a multiplicative component that we estimate nonparametrically. For the short‐run dynamics, we use a GJR‐GARCH model for the conditional variances and augmented DCC models for the conditional correlations. We also introduce exogenous variables to account for congestion and delivery date effects in short‐term conditional variances. We find different correlation dynamics for long‐ and short‐term contracts and the new model achieves higher forecasting performance compared \to a standard DCC model. Copyright © 2012 John Wiley & Sons, Ltd.
NON‐LINEAR DSGE MODELS AND THE CENTRAL DIFFERENCE KALMAN FILTER
Authors: Andreasen Martin M. 
Published: May 2012

SUMMARYThis paper introduces a quasi maximum likelihood approach based on the central difference Kalman filter to estimate non‐linear dynamic stochastic general equilibrium (DSGE) models with potentially non‐Gaussian shocks. We argue that this estimator can be expected to be consistent and asymptotically normal for DSGE models solved up to third order. These properties are verified in a Monte Carlo study for a DSGE model solved to second and third order with structural shocks that are Gaussian, Laplace distributed, or display stochastic volatility. Copyright © 2012 John Wiley & Sons, Ltd.
Transient alterations of the blood–brain barrier tight junction and receptor potential channel gene expression by chlorpyrifos
Authors: Li Wen , Ehrich Marion 
Published: May 2012

ABSTRACTThe blood–brain barrier (BBB) is formed by specialized endothelial cells lining capillaries in the central nervous system (CNS). We previously demonstrated that exposure to very low concentrations of the organophosphorus insecticide chlorpyrifos (CPF) decreased electrical resistance across the BBB in vitro, indicating a loss of BBB integrity. The present study examined the transient effects of CPF on expression of genes contributing to tight junctions of the BBB. Rat brain endothelial cells (RBE4) were co‐cultured with rat astrocytes on membrane inserts to form an in vitro BBB. The RBE4 cells in the BBB were then exposed to CPF for 2, 4 and 12 h. Total RNA was extracted from RBE4 cells and quantitative real‐time PCR (qRT‐PCR) was used to quantify levels of gene expression of tight junction proteins claudin5, scaffold proteins zona occludens (ZO1) and transient receptor potential (canonical) channels (TRPC4). Gene expression decreased 2 h after exposure to CPF, especially TRPC4, but the effects were reversed 12 h later. CPF exposure for only 15 min caused less effect than longer exposures, with TRPC4 gene expression above the control at 4 h. These results suggest that altering gene expression for claudin5, TRPC4 and ZO1 by CPF may directly contribute to BBB disruption, and that the alteration is reversible upon removal of CPF. Copyright © 2012 John Wiley & Sons, Ltd.
Modulation of aryl hydrocarbon receptor‐regulated genes by acute administration of ammonium metavanadate in kidney, lung and heart of C57BL/6 mice
Authors: Abdelhamid Ghada , Amara Issa E.A. , Anwar‐Mohamed Anwar , El‐Kadi Ayman O.S. 
Published: May 2012

ABSTRACTWe recently reported that vanadium (V5+) was able to decrease the 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD)‐mediated induction of Cyp1a1 and Nqo1 at mRNA, protein and catalytic activity levels in mouse hepatoma Hepa 1c1c7 and human hepatoma HepG2 cells. However, little is known regarding the in vivo effects. Thus, the objective of this study was to investigate whether similar effects would occur at the in vivo level. Therefore, we examined the effect of exposure to V5+ (5 mg kg−1) with or without TCDD (15 µg kg−1) on the AhR‐regulated genes in kidney, lung and heart of C57BL/6 J mice. Our results demonstrated that V5+ alone significantly decreased Cyp1b1 protein and catalytic activity levels in kidney at 24 h. Moreover, it significantly potentiated Nqo1 and Gsta1 gene expression in the heart, and only Gsta1 gene expression in the lung. Upon co‐exposure, we found that V5+significantly inhibited the TCDD‐mediated induction of Cyp1a1, Cyp1a2 and Cyp1b1 mRNA, protein and catalytic activity levels in the kidney at 24 h. On the other hand, V5+ significantly potentiated the TCDD‐mediated induction of Nqo1 and Gsta1 protein and activity levels in the kidney. Cyp1a1, Cyp1b1, Nqo1 mRNA, protein and catalytic activity levels in the lung were significantly potentiated at 6 h. Interestingly, all tested genes in the heart were significantly decreased at 6 h with the exception of Gsta1 mRNA. The present study demonstrates that V5+ modulates TCDD‐induced AhR‐regulated genes. Furthermore, the effect on one of these enzymes could not be generalized to other enzymes even if it was in the same organ. Copyright © 2012 John Wiley & Sons, Ltd.
Nanoparticulate silver increases uric acid and allantoin excretion in rats, as identified by metabolomics
Authors: Hadrup Niels , Lam Henrik R. , Loeschner Katrin , Mortensen Alicja , Larsen Erik H. , Frandsen Henrik 
Published: May 2012

ABSTRACTMetabolomic investigation of rat urine was employed to identify mammalian metabolites affected by ionic or nanoparticulate silver. Female and male Wistar rats were administered silver nanoparticles (2.25, 4.5 or 9.0 mg kg−1 body weight per day) or ionic silver (silver acetate, 9.0 mg silver kg−1 bw per day) by oral gavage for 28 days. On day 18, urine was collected for 24 h and subjected to metabolomics with high performance liquid chromatography–quadropole time‐of‐flight mass spectrometry (HPLC‐QTOF‐MS)‐based separation and detection. Principal component analysis was subsequently applied to the data. Metabolomic differences in urine composition were found in female rats but not in male rats. Several metabolites were identified by the use of elemental composition calculated from the exact mass combined with searches in the Human Metabolome Database.The metabolite identities were eventually verified by co‐chromatography with authentic standards. Differences were found in uric acid and its degradation product, allantoin. Administration of nanoparticulate silver increased both metabolites, whereas ionic silver only increased allantoin. In conclusion, metabolomic investigation of rat urine showed that increased levels of uric acid and allantoin were associated with exposure to nanoparticulate silver. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of Prolonged Storage of Seminal Plasma on Levels of Calcium and Magnesium
Authors: Valsa J. , Skandhan K. P. , Sumangala B. , Sahab Khan P. , Amith S. 
Published: May 2012

BackgroundIn laboratories, the semen or seminal plasma samples are stored before estimation of different elements without knowing the adverse effect of storing. The present study shows the levels of Ca++ and Mg++ in the seminal plasma before and after the storage.MethodsAtomic absorption spectrophotometry (AAS) was used for estimating calcium and magnesium levels in the seminal plasma. Samples were stored for one year in different containers such as polyethylene, plastic, ordinary glass, and borosil glass. Calcium and magnesium levels were estimated after this period by AAS. The total area in contact with containers was considered in the final calculation.ResultsAfter 1‐year storage, the levels of calcium and magnesium had changed. The most suitable container for storage of calcium was ordinary glass (P > 0.05) whereas ordinary glass (P > 0.05), polyethylene (P > 0.05), and borosil glass (P > 0.05) are the most suitable for magnesium.ConclusionIn any elemental study, the most suitable containers are recommended for storage of the semen/seminal plasma samples. J. Clin. Lab. Anal. 26:315‐316, 2012. © 2012 Wiley Periodicals, Inc.
Cross‐lagged associations between perceived external employability, job insecurity, and exhaustion: Testing gain and loss spirals according to the Conservation of Resources Theory
Authors: De Cuyper Nele , Mäkikangas Anne , Kinnunen Ulla , Mauno Saija , Witte Hans De 
Published: May 2012

SummaryThis study investigates perceived external employability (PEE) as a personal resource in relation to job insecurity and exhaustion. We advance the idea that PEE may reduce feelings of job insecurity and, through felt job insecurity, also exhaustion. That is, we probe the paths from PEE to job insecurity and from job insecurity to exhaustion. We furthermore account for possible reversed causality, so that exhaustion → felt job insecurity and felt job insecurity → PEE. This aligns with insights from the Conservation of Resources Theory, which is built on the assumption of resource caravans passageways and associated gain and loss spirals. We based the results on a sample of 1314 workers from two Finnish universities. Respondents participated twice in the study with a time lag of one year. We found that PEE related negatively to felt job insecurity and vice versa. Similarly, there was a reciprocal positive relationship between felt job insecurity and exhaustion. We conclude that PEE may prevent feelings of insecurity and, through reduced job insecurity, also exhaustion. Copyright © 2012 John Wiley & Sons, Ltd.
Doubly Biomimetic Catecholic Phosphorylcholine Copolymer: A Platform Strategy for Fabricating Antifouling Surfaces
Authors: Gong Yong‐Kuan , Liu Li‐Ping , Messersmith Phillip B. 
Published: May 2012

AbstractA doubly biomimetic PMNC polymer bearing cell antifouling phosphorylcholine and mussel adhesive protein catechol groups is synthesized. The polymer can be deposited onto a variety of substrates by dip‐coating in an aqueous solution, adhering to surfaces via the catechol functional group while at the same time forming a cell outer membrane mimetic antifouling surface. Contact angle, ATR‐FTIR and XPS measurements confirm polymer coating formation on a variety of inorganic and organic substrates. BSA and bovine plasma fibrinogen protein adsorption on PMNC coated surfaces are reduced significantly compared to unmodified substrates, and platelet adhesion from human serum onto the PMNC coated substrate surfaces is highly suppressed in this study.magnified image
Dynamic Homogeneity by Architectural Design – Bottlebrush Polymers
Authors: Grigoriadis Christos , Nese Alper , Matyjaszewski Krzysztof , Pakula Tadeusz , Butt Hans‐Jürgen , Floudas George 
Published: May 2012

AbstractThe self‐organization and dynamics of bottlebrush polymers consisting of poly(2‐bromoisobutyryloxyethyl methacrylate) (PBiBEM) backbone and grafted n‐butyl acrylate (PBA) chains are studied as a function of the side‐chain length by X‐ray scattering, dielectric spectroscopy, and rheology in relation to the respective homopolymers. All short‐range correlations are dominated by the PBA side chains, whereas long‐range correlations reflect the screening of the backbones by the side chains. Such correlations show up also in the segmental dynamics. The PBA segmental dynamics are slowed‐down, whereas the backbone dynamics are plasticized by the side chains. Overall the bottle‐brush architecture imparts dynamic homogeneity to the backbone and side‐chain dynamics.
Dispersing Graphene in Hydroxypropyl Cellulose by Utilizing its LCST Behavior
Authors: Liao Ruijuan , Lei Yanda , Wan Jingjing , Tang Zhenghai , Guo Baochun , Zhang Liqun 
Published: May 2012

AbstractA novel method for producing graphene/hydroxypropyl cellulose (HPC) composite with a fine dispersion of graphene is established. The thermoresponsive HPC, with low a critical solution temperature (LCST) behavior, becomes self‐associated into nanospheres when its homogeneous solution is heated to a temperature higher than the LCST. The formed nanospheres of HPC can then “clamp” graphene layers and get them finely dispersed in solution and in the polymer matrix. Incorporating graphene via this method can largely prevent graphene from agglomeration. Compared with the conventional casting method, the proposed LCST method can further enhance the electrical conductivity of HPC/graphene composites by 2–3 orders of magnitude. The percolation threshold value of RGO loading is as low as 0.11 vol%.
Creep and Failure Time of Aramid Yarns Subjected to Constant Load
Authors: Knoester Henk , den Decker Piet , van den Heuvel Jurriaan , Tops Niek , Elkink Frits 
Published: May 2012

AbstractThe lifetime of synthetic yarns subjected to constant load is generally described by an empirical model expressing the logarithm of “time‐to‐failure” as a linear decreasing function of the applied load or, alternatively, by means of a power‐law equation. The failure of aramid yarns is systematically explored here and both models are successfully used to fit the experimental data. The models are extended to describe yarn failure on filament level. Application of these models to the experimental data shows that, independent of a visco‐elastic response, failure can be interpreted in terms of an almost constant rate damage accumulation prior to an avalanche of breaking filaments (yarn failure).magnified image
Templation, Water Content, and Zeta Potential of Polyelectrolyte Nanoassemblies: a Comparison Between Polyelectrolyte Multilayers and Brushes
Authors: Moya Sergio Enrique , Iturri Ramos Jagoba Jon , Llarena Irantzu 
Published: May 2012

AbstractThis feature article deals with the self assembly and physical chemistry of polyelectrolytes: multilayers and brushes. The article highlights the interesting behavior of polyelectrolytes in nanoscale assemblies, giving more insight into the complexity of the formation of the assemblies. The water content of multilayers and brushes is studied during the assembly and in different ionic strengths. Similarities are found in the behavior of the brushes and multilayers with ionic strength, with regard to changes in the thickness and the water content. An invariance of the zeta potential with ionic strength is also observed for both systems, which can be explained as a result of conformational changes of the polymer chains. Finally, the combination of brushes and multilayers for surface modification is presented.
Catenated PS–PMMA Block Copolymers via Supramolecularly Templated ATRP Initiator Approach
Authors: Bunha Ajay Kumar , Mangadlao Joey , Felipe Mary Jane , Pangilinan Katrina , Advincula Rigoberto 
Published: May 2012

AbstractA novel route to synthesize catenated macrocyclic PS–PMMA block copolymers is demonstrated via combination of supramolecular chemistry and controlled radical polymerization (CRP). Polymerization of styrene with bromopropionate ester initiator coupled with phenanthroline Cu(I) complex affords a four arm PS macroinitiator, which upon further chain extension by polymerization of MMA generates a four arm PS–PMMA block copolymer. Intramolecular coupling of PS–PMMA–Br arms via low temperature styrene‐assisted atom transfer radical coupling (ATRC) leads to the formation of PS–PMMA catenand, which generates the metal‐free catenated macrocyclic PS–PMMA block copolymer after removal of Cu metal. The interlocked structures of catenated block copolymers are confirmed by GPC, NMR, and AFM image analysis.
An Emulsifier‐Free RAFT‐Mediated Process for the Efficient Synthesis of Cerium Oxide/Polymer Hybrid Latexes
Authors: Garnier Jérôme , Warnant Jérôme , Lacroix‐Desmazes Patrick , Dufils Pierre‐Emmanuel , Vinas Jérôme , Vanderveken Yves , van Herk Alex M. 
Published: May 2012

AbstractHybrid latexes based on cerium oxide nanoparticles are synthesized via an emulsifier‐free process of emulsion polymerization employing amphiphatic macro‐RAFT agents. Poly(butyl acrylate‐co‐acrylic acid) random oligomers of various compositions and chain lengths are first obtained by RAFT copolymerization in the presence of a trithiocarbonate as controlling agent. In a second step, the seeded emulsion copolymerization of styrene and methyl acrylate is carried out in the presence of nanoceria with macro‐RAFT agents adsorbed at their surface, resulting in a high incorporation efficiency of cerium oxide nanoparticles in the final hybrid latexes, as evidenced by cryo‐transmission electron microscopy.
Effect of Nonsolvent on the Formation of Polymer Nanomaterials in the Nanopores of Anodic Aluminum Oxide Templates
Authors: Lee Chih‐Wei , Wei Tzu‐Hui , Chang Chun‐Wei , Chen Jiun‐Tai 
Published: May 2012

AbstractWe study the effect of nonsolvent on the formation of polymer nanomaterials in the nanopores of porous templates. Water (nonsolvent) is added into a poly (methyl methacrylate) (PMMA) solution in dimethylformamide (DMF) confined in the nanopores of an anodic aluminum oxide (AAO) template. Water forms a wetting layer on the pore wall and causes the PMMA solution to be isolated in the center of the nanopore, resulting in the formation of PMMA nanospheres or nanorods after the solvent is evaporated. The formation of the polymer nanomaterials induced by nonsolvent is found to be driven by the Rayleigh‐instability‐type transformation. Without adding the nonsolvent, PMMA chains precipitate on the walls of the nanopores after the solvent is evaporated, and PMMA nanotubes are obtained.
Nutritional B vitamin deficiency disrupts lipid metabolism causing accumulation of proatherogenic lipoproteins in the aorta adventitia of ApoE null mice
Authors: McNeil Christopher J. , Beattie John H. , Gordon Margaret‐Jane , Pirie Lynn P. , Duthie Susan J. 
Published: May 2012

ScopeCardiovascular disease is the major cause of death in the world. Low dietary folate, elevated homocysteine, and high circulating cholesterol are risk factors.Methods and resultsWe investigated whether folate and/or B vitamin deficiency would change lipoprotein and fatty acid metabolism and lipid accumulation in the aorta adventitia of ApoE null mice. Mice (n = 10 per group) were fed a control (C; 4%) or high saturated fat (HF; 21%), and high cholesterol (0.15%) diet for 16 weeks. Folate (F‐) or folate, B6 and B12 deficiency (F‐B‐) were imposed on these diets. Feeding a HF diet increased plasma and liver total cholesterol and HDL cholesterol (two‐ to threefold; p < 0.05). Total cholesterol increased (twofold; p < 0.05) in aorta adventitial lipid in response to HF. Feeding a diet depleted of folate and B vitamins (F‐B‐) significantly increased cholesterol accumulation in both liver and aorta adventitial lipid (approximately 50–70%; p < 0.05). Moreover, the proportions of fatty acids in hepatic and adventitial lipid was significantly changed by B vitamin depletion, measured as an increase in saturated fatty acids (approximately 15%) and a decrease (approximately 11%) in monounsaturated fatty acids (p < 0.05).ConclusionB vitamin deficiency perturbs lipid metabolism in ApoE null mice, causing accumulation of proatherogenic cholesterol and fatty acids in the aorta adventitia.
Arachidonic acid/docosahexaenoic acid‐supplemented diet in early life reduces body weight gain, plasma lipids, and adiposity in later life in ApoE*3Leiden mice
Authors: Wielinga Peter Y. , Harthoorn Lucien F. , Verschuren Lars , Schoemaker Marieke H. , Jouni Zeina E. , van Tol Eric A.F. , Kleemann Robert , Kooistra Teake 
Published: May 2012

ScopeThis study addresses whether early life arachidonic acid (ARA)/docosahexaenoic acid (DHA) supplementation or eicosapentaenoic acid (EPA)/DHA (Omacor) supplementation affects body weight gain, lipid metabolism, and adipose tissue quantity and quality in later life in ApoE*3Leiden‐transgenic mice, a humanized model for hyperlipidemia and mild obesity.Methods and resultsFour‐week‐old male ApoE*3Leiden mice were fed chow diet with or without a mixture of ARA (0.129 wt%) and DHA (0.088 wt%) or Omacor (0.30 wt% EPA, 0.25 wt% DHA). At age 12 weeks, mice were fed high‐fat/high‐carbohydrate (HFHC) diet without above supplements until age 20 weeks. Control mice received chow diet throughout the study. Mice receiving ARA/DHA gained less body weight compared to control and this effect was sustained when fed HFHC. Omacor had no significant effect on body weight gain. Plasma cholesterol and triglycerides were significantly lowered by both supplementations. At 20 weeks, epididymal fat mass was less in ARA/DHA‐supplemented mice, while Omacor had no significant effect on fat mass. Both ARA/DHA and Omacor reduced inguinal adipocyte cell size; only ARA/DHA significantly reduced epididymal macrophage infiltration.ConclusionThis study shows that early life ARA/DHA, but not Omacor supplementation improves body weight gain later in life. ARA/DHA and to a lesser extent Omacor both improved adipose tissue quality.