bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of bovine plasma semicarbazide‐sensitive amine oxidase by caffeine
Authors: Olivieri A. , Tipton K. 
Published: May 2010

AbstractSemicarbazide‐sensitive amine oxidase (SSAO) is a copper‐containing enzyme that catalyzes the oxidative deamination of endogenous and exogenous primary amines. SSAO exists in mammals both as a plasma‐soluble and as a membrane‐bound form, and its active site is able to come into contact with numerous xenobiotic, amine‐containing compounds. The kinetic studies performed in this work showed that caffeine inhibition of bovine serum amine oxidase was noncompetitive when benzylamine was used as substrate and mixed when the substrate used was methylamine. Since caffeine contains an imidazole ring, it cannot be excluded that it might bind to an inhibitory imidazoline‐binding site on SSAO. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 25:26–27 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.20356
Central nervous system cytokine gene expression: Modulation by lead
Authors: Kasten‐Jolly Jane , Heo Yong , Lawrence David A. 
Published: May 2010

AbstractThe environmental heavy metal toxicant, lead (Pb) has been shown to be more harmful to the central nervous system (CNS) of children than to adults, given that Pb exposure affects the neural system during development. Because growth factors and cytokines play very important roles in development of the CNS, we have examined the impact of Pb exposure on the expression of cytokines during CNS development. Cytokine expression was studied in post‐natal‐day 21 (pnd21) mice by microarray, real‐time RT‐PCR, Luminex, and ELISA methodologies. BALB/c mouse pups were exposed to Pb through the dam's drinking water (0.1 mM Pb acetate), from gestation‐day 8 (gd8) to pnd21. Two cytokines, interleukin‐6 (IL‐6) and transforming growth factor‐β1 (TGF‐β1), displayed significantly changed transcript levels in the presence of Pb. IL‐6 and TGF‐β1 both have signal transduction cascades that can cooperatively turn on the gene for the astrocyte marker glial‐fibrillary acidic protein (GFAP). Microarray results indicated that Pb exposure significantly increased expression of GFAP. Pb also modulated IL‐6, TGF‐β1, and IL‐18 protein expression in select brain regions. The deleterious effects of Pb on learning and long‐term memory are posited to result from excessive astrocyte growth and/or activation with concomitant interference with neural connections. Differential neural expression of cytokines in brain regions needs to be further investigated to mechanistically associate Pb and neuroinflammation with behavioral and cognitive changes. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 25:41–54 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.20358
The study of vapour phase hydrogen peroxide decontamination process as a potential method for degradation of organic pollutants
Authors: Švrček Jiří , Marhoul Antonín , Kačer Petr , Kuzma Marek , Pánek Libor , Červený Libor 
Published: May 2010

AbstractBACKGROUND: The work is focused on the application of vapour phase hydrogen peroxide (VPHP) as a highly promising and effective decontamination technique. The aim of this work was to assess the use of this validated technique for the removal of chemicals from contaminated surfaces and examine the impact of key parameters on the course of the decontamination process.RESULTS: Unique sophisticated laboratory equipment was developed to test the effect of VPHP on chemical substances. It was used for the evaluation of the role of crucial parameters such as the relative humidity, condensation and synergistic effect of UV radiation on the VPHP agent efficiency on a model compound (vanillin) degradation. The degradation rate of the model substance was notably affected by all these factors.CONCLUSION: VPHP could be used for an efficient decomposition of vanillin. The course of the decontamination process was strongly influenced by condensation (showing a substantial difference between ‘wet’ and ‘dry’ processes) and the synergistic effect of UV radiation influencing the reaction rate and degree of decomposition. Copyright © 2010 Society of Chemical Industry
A novel on‐line optical method for algae measurement
Authors: Liang Heng , Nan Jun , Zhang Xinxin , Chen Zhonglin , Tian Jiayu , Li Guibai 
Published: May 2010

AbstractIn recent years, algal blooms have occurred worldwide, and algae‐rich water often has adverse effects on water production. The technique of algae measurement is a critical issue for adjusting water treatment processes according to the numbers of algae cells. The algae particles in the water are generally 2–200 µm in size with only a few smaller than 2 µm. The traditional algae measuring method is by visual observation with an optical microscope. However, traditional visual observation often needs 48 h fixing time, which makes the measurement results lag behind the needs of water production. To solve the problem, this study employed on‐line optical devices to improve the efficiency and accuracy of algae measurement. A photometric dispersion analyzer (PDA) and particle counting analyzer (PCA) were jointly utilized to monitor on‐line the algae concentration in natural water. Algae cells can be classified by different sizes. It was found that there was good correlation between R2PDA and total algae counts in water. The PCA could quantitatively characterize the algae counts and species distribution of dominant algae species in real water. PDA and PCA could be used jointly to define on‐line the characteristics of real water containing mixed algae. Copyright © 2010 Society of Chemical Industry
Reducing the formation of FIB‐induced FCC layers on Cu‐Zn‐Al austenite
Authors: Zelaya Eugenia , Schryvers Dominique 
Published: May 2010

AbstractThe irradiation effects of thinning a sample of a Cu‐Zn‐Al shape memory alloy to electron transparency by a Ga+ focused ion beam were investigated. This thinning method was compared with conventional electropolishing and Ar+ ion milling. No implanted Ga was detected but surface FCC precipitation was found as a result of the focused ion beam sample preparation. Decreasing the irradiation dose by lowering the energy and current of the Ga+ ions did not lead to a complete disappearance of the FCC structure. The latter could only be removed after gentle Ar+ ion milling of the sample. It was further concluded that the precipitation of the FCC is independent of the crystallographic orientation of the surface. Microsc. Res. Tech. 74:84‐91, 2011. © 2010 Wiley‐Liss, Inc.
Feasibility of in vivo measurement of carotid wall shear rate using spiral fourier velocity encoded MRI
Authors: Carvalho Joao L. A. , Nielsen Jon‐Fredrik , Nayak Krishna S. 
Published: May 2010

AbstractArterial wall shear stress is widely believed to influence the formation and growth of atherosclerotic plaque; however, there is currently no gold standard for its in vivo measurement. The use of phase contrast MRI has proved to be challenging due to partial‐volume effects and inadequate signal‐to‐noise ratio at the high spatial resolutions that are required. This work evaluates the use of spiral Fourier velocity encoded MRI as a rapid method for assessing wall shear rate in the carotid arteries. Wall shear rate is calculated from velocity histograms in voxels spanning the blood/vessel wall interface, using a method developed by Frayne and Rutt (Magn Reson Med 1995;34:378–387). This study (i) demonstrates the accuracy of the velocity histograms measured by spiral Fourier velocity encoding in a pulsatile carotid flow phantom compared with high‐resolution two‐dimensional Fourier transform phase contrast, (ii) demonstrates the accuracy of Fourier velocity encoding–based shear rate measurements in a numerical phantom designed using a computational fluid dynamics simulation of carotid flow, and (iii) demonstrates in vivo measurement of regional wall shear rate and oscillatory shear index in the carotid arteries of healthy volunteers at 3 T. Magn Reson Med 63:1537–1547, 2010. © 2010 Wiley‐Liss, Inc.
Fast, simple gradient delay estimation for spiral MRI
Authors: Robison Ryan K. , Devaraj Ajit , Pipe James G. 
Published: May 2010

AbstractTiming delays between data acquisition and gradient transmission result in image degradation. This is especially true in spiral MRI, where delays can alter data in a nonuniform manner, generating significant artifact in the reconstructed data. The many methods that exist to mitigate these delays or measure the k‐space coordinates require long measurement times, complicated analysis, specialized phantoms or hardware, or significant changes to the sequence of interest. A fast and simple method is proposed to measure delays on each gradient channel. It requires only minimal modification to an existing spiral sequence and can be used to measure independent delays on three gradient channels and any scan subject within six sequence repetition times. The effectiveness and accuracy of this method are analyzed. Magn Reson Med 63:1683–1690, 2010. © 2010 Wiley‐Liss, Inc.
Combined arterial spin label and dynamic susceptibility contrast measurement of cerebral blood flow
Authors: Zaharchuk Greg , Straka Matus , Marks Michael P. , Albers Gregory W. , Moseley Michael E. , Bammer Roland 
Published: May 2010

AbstractDynamic susceptibility contrast (DSC) and arterial spin labeling (ASL) are both used to measure cerebral blood flow (CBF), but neither technique is ideal. Absolute DSC‐CBF quantitation is challenging due to many uncertainties, including partial‐ volume errors and nonlinear contrast relaxivity. ASL can measure quantitative CBF in regions with rapidly arriving flow, but CBF is underestimated in regions with delayed arrival. To address both problems, we have derived a patient‐specific correction factor, the ratio of ASL‐ and DSC‐CBF, calculated only in short‐arrival‐time regions (as determined by the DSC‐based normalized bolus arrival time [Tmax]). We have compared the combined CBF method to gold‐standard xenon CT in 20 patients with cerebrovascular disease, using a range of Tmax threshold levels. Combined ASL and DSC CBF demonstrated quantitative accuracy as good as the ASL technique but with improved correlation in voxels with long Tmax. The ratio of MRI‐based CBF to xenon CT CBF (coefficient of variation) was 90 ± 30% (33%) for combined ASL and DSC CBF, 43 ± 21% (47%) for DSC, and 91 ± 31% (34%) for ASL (Tmax threshold 3 sec). These findings suggest that combining ASL and DSC perfusion measurements improves quantitative CBF measurements in patients with cerebrovascular disease. Magn Reson Med 63:1548–1556, 2010. © 2010 Wiley‐Liss, Inc.
Cardiac 17O MRI: Toward direct quantification of myocardial oxygen consumption
Authors: McCommis Kyle S. , He Xiang , Abendschein Dana R. , Gupte Pradeep M. , Gropler Robert J. , Zheng Jie 
Published: May 2010

AbstractA new 17O‐labeled blood contrast agent was injected intravenously in control dogs. Electrocardiogram (ECG)‐triggered myocardial T1ρ imaging was performed to obtain spin‐locking T1ρ‐weighted myocardial signals for the detection of resultant metabolite H217O water in the heart. Bolus and slow injection methods of various doses of the 17O‐labeled and 16O‐labeled agents were carried out in order to evaluate the sensitivity of this method and determine the optimal injection method. Bolus injection provided approximately 1% signal reduction, whereas slow injection with larger amount of agent yielded 11.9 ± 0.6% signal reduction. Myocardial oxygen consumption rate was determined by a technique to quantify cerebral oxygenation consumption rate previously developed in 17O brain studies. With either injection method, myocardial oxygen consumption rate at rest was 5.0 – 5.6 μmol/g/min. Therefore, it appears feasible to detect metabolically generated HO water in vivo in the heart, using the 17O‐labeled blood tracer. Myocardial oxygen consumption rate can then be quantified in vivo, which may open new doors for the assessment of myocardial metabolism. Magn Reson Med 63:1442–1447, 2010. © 2010 Wiley‐Liss, Inc.
Three‐point dixon method enables whole‐body water and fat imaging of obese subjects
Authors: Berglund Johan , Johansson Lars , Ahlström Håkan , Kullberg Joel 
Published: May 2010

AbstractDixon imaging techniques derive chemical shift‐separated water and fat images, enabling the quantification of fat content and forming an alternative to fat suppression. Whole‐body Dixon imaging is of interest in studies of obesity and the metabolic syndrome, and possibly in oncology. A three‐point Dixon method is proposed where two solutions are found analytically in each voxel. The true solution is identified by a multiseed three‐dimensional region‐growing scheme with a dynamic path, allowing confident regions to be solved before unconfident regions, such as background noise. 2π‐Phase unwrapping is not required. Whole‐body datasets (256 × 184 × 252 voxels) were collected from 39 subjects (body mass index 19.8‐45.4 kg/m2), in a mean scan time of 5 min 15 sec. Water and fat images were reconstructed offline, using the proposed method and two reference methods. The resulting images were subjectively graded on a four‐grade scale by two radiologists, blinded to the method used. The proposed method was found superior to the reference methods. It exclusively received the two highest grades, implying that only mild reconstruction failures were found. The computation time for a whole‐body dataset was 1 min 51.5 sec ± 3.0 sec. It was concluded that whole‐body water and fat imaging is feasible even for obese subjects, using the proposed method. Magn Reson Med 63:1659–1668, 2010. © 2010 Wiley‐Liss, Inc.
Optimal radiofrequency and gradient spoiling for improved accuracy of T1 and B1 measurements using fast steady‐state techniques
Authors: Yarnykh Vasily L. 
Published: May 2010

AbstractVariable flip angle T1 mapping and actual flip‐angle imaging B1 mapping are widely used quantitative MRI methods employing radiofrequency spoiled gradient‐echo pulse sequences. Incomplete elimination of the transverse magnetization in these sequences has been found to be a critical source of T1 and B1 measurement errors. In this study, comprehensive theoretical analysis of spoiling‐related errors in variable flip angle and actual flip‐angle imaging methods was performed using the combined isochromat summation and diffusion propagator model and validated by phantom experiments. The key theoretical conclusion is that correct interpretation of spoiling phenomena in fast gradient‐echo sequences requires accurate consideration of the diffusion effect. A general strategy for improvement of T1 and B1 measurement accuracy was proposed based on the strong spoiling regimen, where diffusion‐modulated spatial averaging of isochromats becomes a dominant factor determining magnetization evolution. Practical implementation of strongly spoiled variable flip angle and actual flip‐angle imaging techniques requires sufficiently large spoiling gradient areas (AG) in combination with optimal radiofrequency phase increments (ϕ0). Optimal regimens providing <2% relative T1 and B1 measurement errors in a variety of tissues were theoretically derived for prospective in vivo variable flip angle (pulse repetition time = 15–20 ms, AG = 280–450 mT·ms/m, ϕ0 = 169°) and actual flip‐angle imaging (pulse repetition time1/pulse repetition time2 = 20/100 ms, AG1/AG2 = 450/2250 mT·ms/m, ϕ0 = 39°) applications based on 25 mT/m maximal available gradient strength. Magn Reson Med 63:1610–1626, 2010. © 2010 Wiley‐Liss, Inc.
Vessel imaging with viable tumor analysis for quantification of tumor angiogenesis
Authors: Ungersma Sharon E. , Pacheco Glenn , Ho Calvin , Yee Sharon Fong , Ross Jed , van Bruggen Nicholas , Peale Franklin V. , Ross Sarajane , Carano Richard A. D. 
Published: May 2010

AbstractImaging of tumor microvasculature has become an important tool for studying angiogenesis and monitoring antiangiogenic therapies. Ultrasmall paramagnetic iron oxide contrast agents for indirect imaging of vasculature offer a method for quantitative measurements of vascular biomarkers such as vessel size index, blood volume, and vessel density. Here, this technique is validated with direct comparisons to ex vivo micro‐CT angiography and histologic vessel measurements, showing significant correlations between in vivo vascular MRI measurements and ex vivo structural vessel measurements. The sensitivity of the MRI vascular parameters is also demonstrated, in combination with a multispectral analysis technique for segmenting tumor tissue to restrict the analysis to viable tumor tissue and exclude regions of necrosis. It is shown that this viable tumor segmentation increases sensitivity for detection of significant effects on blood volume and vessel density by two antiangiogenic therapeutics (anti‐VEGF and anti‐neuropilin‐1) on an HM7 colorectal tumor model. Anti‐VEGF reduced blood volume by 36 ± 3% (P < 0.0001) and vessel density by 52 ± 3% (P < 0.0001) at 48 h posttreatment; the effects of anti‐neuropilin‐1 were roughly half as strong with a reduction in blood volume of 18 ± 6% (P < 0.05) and a reduction in vessel density of 33 ± 5% (P < 0.05) at 48 h posttreatment. Magn Reson Med 63:1637–1647, 2010. © 2010 Wiley‐Liss, Inc.
Susceptibility tensor imaging
Authors: Liu Chunlei 
Published: May 2010

AbstractHeterogeneity of magnetic susceptibility within brain tissues creates unique contrast between gray and white matter in magnetic resonance phase images acquired by gradient echo sequences. Detailed understanding of this contrast may provide meaningful diagnostic information. In this communication, we report an observation of extensive anisotropic magnetic susceptibility in the white matter of the central nervous system. Furthermore, we describe a susceptibility tensor imaging technique to measure and quantify this phenomenon. This technique relies on the measurement of resonance frequency offset at different orientations with respect to the main magnetic field. We propose to characterize this orientation variation using an apparent susceptibility tensor. The susceptibility tensor can be decomposed into three eigenvalues (principal susceptibilities) and associated eigenvectors that are coordinate‐system independent. We show that the principal susceptibilities offer strong contrast between gray and white matter, whereas the eigenvectors provide orientation information of an underlying magnetic network. We believe that this network may further offer information of white matter fiber orientation. Magn Reson Med 63:1471–1477, 2010. © 2010 Wiley‐Liss, Inc.
Effect of solvent on the free radical polymerization of N,N‐dimethylacrylamide
Authors: Valdebenito Andrea , Encinas María Victoria 
Published: May 2010

AbstractThe free radical photopolymerization of N,N‐dimethylacrylamide was investigated at 25 °C and at low conversion in several solvents ranging from weak polar solvents to water. The polymerization is strongly accelerated in the aqueous medium, with the polymerization rate increasing one order of magnitude when the solvent is changed from an organic one to aqueous medium. These results were analysed in terms of macroradical conformation, effect of medium viscosity, aggregate formation, hydrogen bond formation and effect of temperature. The results suggest that the main factor that controls the polymerization rate is a kinetic effect due to the hydrogen bonding between the amide carbonyl group and water molecules. Also, we found that polymer properties, such as the thermodynamic quality of the solvent for the polymer backbone and molecular weight control using transfer agents, are influenced by the intermolecular hydrogen bonding. Copyright © 2010 Society of Chemical Industry
Magnetization‐prepared NMR imaging of water penetration into poly(vinyl alcohol)–poly(N‐vinyl‐2‐pyrrolidone) hydrogels
Authors: Zainuddin  , Strounina Ekaterina V , Hill David JT , Whittaker Andrew K 
Published: May 2010

AbstractPoly(vinyl alcohol)–poly(N‐vinyl‐2‐pyrrolidone) (PVA–PVP) polymer network hydrogels were prepared by subjecting an aqueous solution of PVA–PVP to gamma irradiation. The hydrogels had initial water contents of approximately 87%, and upon further immersion in water the hydrogels absorbed significantly more, reaching a final water content of about 95%. The use of magnetization‐prepared NMR imaging enabled acquisition of T2‐weighted NMR images from which T2 maps were constructed and subsequently instantaneous concentration profiles of water molecules were determined. The concentration profiles could be described using Fick's second law of diffusion and the resultant diffusion coefficients were in excellent agreement with those determined from mass‐uptake measurements reported previously. In addition an apparent change in water content over longer times was observed from the NMR images. This phenomenon could be attributed to changes in the distribution of T2 relaxation times due to rearrangement of the water molecules, or alternatively diffusion of non‐crosslinked polymer chains out of the hydrogel network. Copyright © 2010 Society of Chemical Industry
Design and simulations of novel enhancement‐mode high‐voltage GaN vertical hybrid MOS‐HEMTs
Authors: Li Z. , Tang K. , Chow T. P. , Sugimoto M. , Uesugi T. , Kachi T. 
Published: May 2010

AbstractThe design, simulations and optimization of a novel high‐voltage vertical GaN MOS‐controlled High Electron Mobility Transistor (HEMT) with epitaxially grown thin p type body and terrace gate structure is presented, with projected maximum breakdown voltage of 1289 V, Ron,sp of 1.9 mΩ‐cm2, and switching power loss of 34.9 μJ/cm2 and 2.60 μJ/cm2 for drain and gate respectively. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of low charge carrier wave function overlap on internal quantum efficiency in GaInN quantum wells
Authors: Netzel Carsten , Hoffmann Veit , Wernicke Tim , Knauer Arne , Weyers Markus , Kneissl Michael 
Published: May 2010

AbstractTo determine relevant processes affecting the internal quantum efficiency in GaInN quantum well structures, we have studied the temperature and excitation power dependent photoluminescence intensity for quantum wells with different well widths on (0001) c‐plane GaN and for quantum wells on nonpolar (11‐20) a‐plane GaN. In thick polar quantum wells, the quantum confined Stark effect (QCSE) causes a stronger intensity decrease with increasing temperature as long as the radiative recombination dominates. At higher temperatures, when the nonradiative recombination becomes more important, thick polar quantum wells feature a lower relative intensity decrease than thinner polar or nonpolar quantum wells. Excitation power dependent photoluminescence points to a transition from a recombination of excitons to a bimolecular recombination of uncorrelated charge carriers for thick polar quantum wells in the same temperature range. This transition might contribute to the limitation of nonradiative recombination by a reduced diffusivity of charge carriers. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)