bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of ozone exposure in rat lungs investigated with hyperpolarized 3He MRI
Authors: Crémillieux Yannick , Servais Stéphane , Berthezène Yves , Dupuich David , Boussouar Aurélien , Stupar Vasile , Pequignot Jean‐Marc 
Published: March 2008

AbstractPurposeTo investigate the effects of subchronic ozone exposure on rat lung ventilation using hyperpolarized (HP) 3He MRI.Materials and MethodsA total of 24 Sprague‐Dawley rats, distributed in one control group and four groups exposed to 0.5 ppm ozone concentration for two days or six days, either continuously (22 hours/day) or alternatingly (12 hours/day). A three‐step MRI protocol was designed and applied to each animal, including: 1) 3He gas distribution images acquired at inspiratory capacity, 2) measurements of intrapulmonary 3He diffusion coefficients, and 3) dynamic ventilation acquisitions performed during lung filling with 3He.ResultsNo differentiation between animals exposed to ozone and control animals was observed from the ventilation images obtained at inspiratory capacity. The 3He diffusion coefficients were not statistically different from one group to another. Ventilation defects, appearing as delayed lung filling regions and heterogeneous lung filling, were observed in the dynamic lung ventilation image series. The percentage of animals with ventilation defects in the control, two‐day, and six‐day exposed groups were equal to 20%, 43% and 75%, respectively. In the subgroup of the animals exposed six days for 12 hours per day, the percentage of animals exhibiting ventilation defects was equal to 85%.ConclusionHeterogeneous obstructive patterns in an experimental animal model of subchronic ozone exposure were observed using HP 3He MRI. J. Magn. Reson. Imaging 2008;27:771–776. © 2008 Wiley‐Liss, Inc.
Two‐dimensional 1H MR spectroscopy of the brain in human immunodeficiency virus (HIV)‐infected children
Authors: Banakar Shida , Thomas M. Albert , Deveikis Audra , Watzl June Q.Y. , Hayes Judy , Keller Margaret A. 
Published: March 2008

AbstractPurposeTo measure cerebral metabolites in brains of human immunodeficiency virus (HIV)‐infected patients using two‐dimensional (2D) proton (1H) magnetic resonance spectroscopy (MRS), which enables more sensitive detection of metabolites at lower concentrations and delineation of the components of the different choline (Ch) groups in the frequency domain when compared to one dimensional (1D) 1H‐MRS.Materials and MethodsWe examined metabolite/creatine (Cr) and metabolite/Ch ratios in the left frontal brain of 10 HIV‐infected (mean age 13.7 ± 4.7 years) and 11 control (mean age 15.3 ± 4.6 years) adolescents and children using 2D localized chemical shift correlated spectroscopy (L‐COSY). The integrated volume under each 2D metabolite peak was calculated with reference to the diagonal creatine methyl peak (Cr_d) or the diagonal choline trimethylamine peak (Ch_d).ResultsIn the HIV‐infected patients, myoinositol (mI)/Cr_d (P = 0.009) and mI/Ch_d (P = 0.006) were elevated. The ratios of the following metabolites were also significantly elevated (P < 0.05): mI‐Ch/Cr_d, γ‐aminobutyrate (GABA)/ Cr_d, GABA/Ch_d, threonine‐lactate (Thr‐Lac)/Cr_d, Thr‐Lac/Ch_d, and N‐acetyl aspartate (NAA)/Cr_d.ConclusionWe have demonstrated for the first time the feasibility of 2D‐MRS in HIV‐infected children and adolescents to assess cerebral metabolites and found elevated mI and elevated GABA, in the left frontal brain of clinically stable HIV‐infected patients. A larger study population is needed to confirm these pilot GABA findings. J. Magn. Reson. Imaging 2008;27:710–717. © 2008 Wiley‐Liss, Inc.
Hyperpolarized 129Xe MRI of the mouse lung at a low xenon concentration using a continuous flow‐type hyperpolarizing system
Authors: Wakayama Tetsuya , Kitamoto Masakazu , Ueyama Tsuyoshi , Imai Hirohiko , Narazaki Michiko , Kimura Atsuomi , Fujiwara Hideaki 
Published: March 2008

AbstractPurposeTo apply a continuous flow‐type hyperpolarizing (CF‐HP) system to lung imaging and investigate the feasibility of hyperpolarized 129Xe MRI at a low xenon concentration.Materials and MethodsUnder two conditions where a 3% or 70% xenon gas mixture was constantly supplied, gas‐ and dissolved‐phase 129Xe images and diffusion‐weighted 129Xe‐gas images were obtained from the mouse lung. Signal‐to‐noise ratio (SNR) of the 129Xe images and the apparent diffusion coefficient (ADC) of xenon were compared between the two gas mixtures.ResultsThe SNR of gas‐ and dissolved‐phase images were 28.9 ± 5.2 and 12.0 ± 2.0, respectively, using the 70% xenon gas mixture, while they were 22.9 ± 4.8 and 6.8 ± 0.6, using the 3% mixture. The ADC of xenon using the 3% xenon gas mixture was approximately 1.5 times higher than that using the 70% one. These results indicated that the high ADC increases the apparent replenishment rate of gas‐phase magnetization, thus resulting in a reduction of the SNR loss induced by diluting xenon with quenching gases.ConclusionThe CF‐HP system is useful for lung imaging at an extremely low concentration of xenon, which enables one to fully restrain an anesthetic effect of xenon and to reduce consumption of xenon in a measurement. J. Magn. Reson. Imaging 2008;27:777–784. © 2008 Wiley‐Liss, Inc.
Reduction of truncation artifacts in rapid 3D articular cartilage imaging
Authors: Rakow‐Penner Rebecca , Gold Garry , Daniel Bruce , Stevens Kate , Rosenberg Jarrett , Mazin Samuel , Pauly John , Glover Gary H. 
Published: March 2008

AbstractPurposeTo reduce Gibbs ringing artifact in three‐dimensional (3D) articular knee cartilage imaging with linear prediction (LP).Materials and MethodsA reconstruction method using LP in 3D was applied to truncated data sets of six healthy knees. The technique first linearizes the data before applying the prediction algorithm. Three radiologists blindly reviewed and ranked images of the full, truncated, and predicted data sets. Statistical analysis of the radiologists' reviews was performed for image quality, clinical acceptability of the images, and equivalence with the gold standard.ResultsLP applied to 3D knee cartilage imaging allows for 40% decreased scan time while providing image quality with statistical equivalence to a full data set.Conclusion3D spoiled gradient echo imaging (SPGR) knee cartilage imaging requires significant scan time. This 40% reduction in scan time will allow such scans to be more feasible without sacrificing clinical acceptability. J. Magn. Reson. Imaging 2008;27:860–865. © 2008 Wiley‐Liss, Inc.
Evaluating local hepatocellular carcinoma recurrence post‐transcatheter arterial chemoembolization: Is diffusion‐weighted MRI reliable as an indicator?
Authors: Goshima Satoshi , Kanematsu Masayuki , Kondo Hiroshi , Yokoyama Ryujiro , Tsuge Yusuke , Shiratori Yoshimune , Onozuka Minoru , Moriyama Noriyuki 
Published: March 2008

AbstractPurposeTo evaluate the detectability of local hepatocellular carcinoma (HCC) recurrence after transcatheter arterial chemoembolization (TACE) by diffusion‐weighted MR imaging in correlation with those of gadolinium‐enhanced MR imaging.Materials and MethodsRespiratory‐triggered diffusion‐weighted MR images (b factor, 500 s/mm2; number of averaging, six were obtained in 25 patients with 39 HCCs. Two independent radiologists evaluated diffusion‐weighted MR images, gadolinium‐enhanced MR images after TACE, and assigned confidence levels for postoperative HCC recurrence. Apparent diffusion coefficients (ADCs) in HCCs were also measured. Sensitivities and specificities were compared using an extension of the McNemar test. Observer performance was also determined by ROC curve analysis.ResultsLocal recurrences in 14 HCCs and complete tumor necrosis in 25 HCCs after TACE were determined. Sensitivity for the detection of local HCC recurrence was higher on gadolinium‐enhanced MR imaging (82%) than on diffusion‐weighted MR imaging (60.7%) for the two readers in combination and separately (P < 0.05). Specificities were comparably high for both sequences. Az values were higher for gadolinium‐enhanced MR images (0.92) than for diffusion‐weighted MR images (0.74) for readers in combination and separately (P < 0.05). Mean ADC values showed an increase after TACE (P < 0.001).ConclusionDiffusion‐weighted MR imaging was not found to be a reliable predictor of local HCC recurrence after TACE as compared with gadolinium‐enhanced MR imaging. J. Magn. Reson. Imaging 2008;27:834–839. © 2008 Wiley‐Liss, Inc.
Minimally invasive precision brain access using prospective stereotaxy and a trajectory guide
Authors: Martin Alastair J. , Hall Walter A. , Roark Christopher , Starr Philip A. , Larson Paul S. , Truwit Charles L. 
Published: March 2008

AbstractPurposeTo evaluate the capabilities of MR‐guided “prospective stereotaxy” methods for accessing brain structures for biopsy or electrode implantation.Materials and MethodsMR‐guided biopsy and deep brain stimulator (DBS) electrode implantations were performed with a trajectory guide and real‐time MR guidance. Imaging methods were used to plan the selected path through the brain, appropriately orient the trajectory guide, and monitor the device insertion to assure technical success and screen for hemorrhage. Assessments of technical success rate, targeting accuracy, and complications associated with this technique were performed.ResultsA total of 187 biopsy procedures were performed with guidance via prospective stereotaxy methods. All brain biopsies were diagnostic and two patients sustained superficial wound infections that were treated successfully with antibiotics. One patient died postoperatively of a myocardial infarction despite preoperative medical clearance. A total of 42 DBS electrode insertions were performed in patients with Parkinson's disease or dystonia. The difference between planned and actual electrode position averaged 1.2 mm ± 0.7 mm on the first pass and only a single brain penetration was required in 90% of electrode insertions. Complications included a single asymptomatic hemorrhage and two early infections, with the latter addressed by an adjustment to sterile practice.ConclusionProspective stereotaxy, in combination with a trajectory guide, has been proven capable of efficiently and accurately targeting structures throughout the brain. J. Magn. Reson. Imaging 2008;27:737–743. © 2008 Wiley‐Liss, Inc.
In vivo ultra‐high‐field magnetic resonance imaging of trabecular bone microarchitecture at 7 T
Authors: Krug Roland , Carballido‐Gamio Julio , Banerjee Suchandrima , Burghardt Andrew J. , Link Thomas M. , Majumdar Sharmila 
Published: March 2008

AbstractPurposeTo investigate the feasibility of 7T magnetic resonance imaging (MRI) to visualize and quantify trabecular bone structure in vivo by comparison with 3T MRI and in vivo three‐dimensional (3D) high‐resolution peripheral quantitative computed tomography (HR‐pQCT).Materials and MethodsThe distal tibiae of 10 healthy volunteers were imaged. Therefore, fully balanced steady state free precession (bSSFP) and spin‐echo (bSSSE) pulse sequences were implemented and optimized for 7T. Structural bone parameters, such as apparent bone‐volume over total‐volume fraction (app.BV/TV), apparent trabecular plate separation (app.TbSp), apparent trabecular plate thickness (app.TbTh), and apparent trabecular plate number (app.TbN), were derived.ResultsAll structural trabecular bone parameters correlated well (r > 0.6) between 7T and 3T, and between 7T and HR‐pQCT (r > 0.69), with the exception of app.TbTh, which correlated modestly (r = 0.41) between field strengths and very low with HR‐pQCT (r < 0.16). Regarding absolute values, app.TbN varied only 4% between field strengths, and only 0.6% between 7T and HR‐pQCT. App.TbSp correlated best between 7T and HR‐pQCT (r = 0.89). Using bSSSE, significant smaller trabecular thickness and significant higher trabecular number were found compared to bSSFP.ConclusionWe concluded that imaging and quantification of the trabecular bone architecture at 7T is feasible and preferably done using bSSSE. There exists great potential for ultra‐high‐field (UHF) MRI applied to trabecular bone measurements. J. Magn. Reson. Imaging 2008;27:854–859. © 2008 Wiley‐Liss, Inc.
Dynamic contrast‐enhanced quantitative perfusion measurement of the brain using T1‐weighted MRI at 3T
Authors: Larsson Henrik B.W. , Hansen Adam E. , Berg Hilde K. , Rostrup Egill , Haraldseth Olav 
Published: March 2008

AbstractPurposeTo develop a method for the measurement of brain perfusion based on dynamic contrast‐enhanced T1‐weighted MR imaging.Materials and MethodsDynamic imaging of the first pass of a bolus of a paramagnetic contrast agent was performed using a 3T whole‐body magnet and a T1‐weighted fast field echo sequence. The input function was obtained from the internal carotid artery. An initial T1 measurement was performed in order to convert the MR signal to concentration of the contrast agent. Pixelwise and region of interest (ROI)‐based calculation of cerebral perfusion (CBF) was performed using Tikhonov's procedure of deconvolution. Seven patients with acute optic neuritis and two patients with acute stroke were investigated.ResultsThe mean perfusion value for ROIs in gray matter was 62 mL/100g/min and 21 mL/100g/min in white matter in patients with acute optic neuritis. The perfusion inside the infarct core was 9 mL/100g/min in one of the stroke patients. The other stroke patient had postischemic hyperperfusion and CBF was 140 mL/100g/min.ConclusionAbsolute values of brain perfusion can be obtained using dynamic contrast‐enhanced MRI. These values correspond to expected values from established PET methods. Furthermore, at 3T pixelwise calculation can be performed, allowing construction of CBF maps. J. Magn. Reson. Imaging 2008;27:754–762. © 2008 Wiley‐Liss, Inc.
Multiresidue method for the analysis of more than 140 pesticide residues in fruits and vegetables by gas chromatography coupled to triple quadrupole mass spectrometry
Authors: Fernández Moreno José Luis , Garrido Frenich A. , Plaza Bolaños Patricia , Martínez Vidal José Luis 
Published: March 2008

AbstractA new multiresidue method has been developed and validated for the determination of more than 140 pesticide residues in cucumber and orange by gas chromatography coupled to triple quadrupole mass spectrometry (GC–QqQ‐MS/MS) in a single run of 25.50 min. The triple quadrupole (QqQ) analyzer simultaneously operated in the selected reaction monitoring (SRM) and selected ion monitoring (SIM) modes, acquiring two or three transitions per compound. Samples were extracted by the application of a single‐phase extraction of 10 g of sample with acetonitrile containing 1% of acetic acid, followed by a liquid–liquid partition formed by the addition of 4 g of MgSO4 and 1 g of NaOAc. A dispersive solid‐phase extraction (D‐SPE) with primary secondary amine (PSA) was applied to clean up the extracts. A final concentration step was included in order to increase sensitivity in the instrumental analysis. The method was properly validated in each matrix in a wide dynamic range (10–400 µg kg−1): this work relies on a new quantification strategy by the use of two calibration curves to increase the dynamic range, which permitted reduction of sample dilutions and increase in sample throughput. Recovery was studied at three concentration levels (11.5, 50.0, and 150.0 µg kg−1), yielding values in the range 70–110% with precision values, expressed as relative standard deviation (RSD), lower than 20 and 25% for the intraday and interday precision, respectively. Limits of quantification (LOQs) were established at 10 µg kg−1, the lowest maximum residue level (MRL) value set by the European Union in vegetables. The method was successfully applied to the analysis of pesticide residues in real samples from the southeastern Spain. Copyright © 2008 John Wiley & Sons, Ltd.
Studies on the heterogeneity of the carotenogenic yeast Rhodotorula mucilaginosa from Patagonia, Argentina
Authors: Libkind Diego , Gadanho Mário , Broock Maria van , Sampaio José Paulo 
Published: March 2008

AbstractThe yeast species Rhodotorula mucilaginosa is considered to be ubiquitous due to its world‐wide distribution in terrestrial, freshwater and marine habitats, and to its ability to colonize a large variety of substrates. In this paper we assess the phenotypic and genetic variability of environmental isolates of R. mucilaginosa collected from natural and artificial environments in Patagonia, Argentina. A total of 97 strains were studied and sorted into three groups based on MSP‐PCR fingerprinting results: A, which comprised 90% of the strains, including the type strain; and B and C which included 2 and 8% of the strains, respectively. The D1D2 sequencing did not differentiate any of the 3 groups, while ITS sequencing validated the existence of group C. This group was composed of Patagonian isolates of diverse origin. DNA‐DNA reassociation studies confirmed the existence of significant genetic differences between group C and the type strain. In this study, which is the first on the intraspecific variability of a large set of R. mucilaginosa isolates, a considerable phenotypic and genetic heterogeneity was observed, however such differences were not enough to refute co‐specificity. The study of Patagonian isolates allowed the detection of a genetically distinct group of R. mucilaginosa strains. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chemotaxis of Pseudomonas sp. to caffeine and related methylxanthines
Authors: Dash Swati Sucharita , Sailaja Nori Sri , Gummadi Sathyanarayana N. 
Published: March 2008

AbstractPseudomonas sp. isolated from soil of coffee plantation area has been shown to degrade higher concentrations of caffeine (∼15 g l–1) by N‐demethylation at a rate higher than what has been reported for any strain so far. This strain exhibits positive chemotaxis towards caffeine (1,3,7‐trimethylxanthine) in swarm plate assay and modified capillary assay in a dose dependant manner. Related methylxanthines and xanthine also act as chemoattractants for the strain with the highest relative chemotactic response (RCR) seen for xanthine. Chemotaxis in Pseudomonas sp. is possibly plasmid mediated as indicated by positive chemotaxis of plasmid transformed E. coli DH5α. The chemotactic abilities of Pseudomonas sp. combined with higher rates of degradation of caffeine can be used in the development of strategies for biodecaffeination of caffeine containing wastes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interaction between carbon and nitrogen metabolism during akinete development in the cyanobacterium Anabaena torulosa
Authors: Ahuja Gurpreet , Khattar Jasvirinder Singh , Sarma Tangirala Anjaneya 
Published: March 2008

AbstractNutrient enrichment with a nitrogen (as nitrate) or carbon (as fructose) source to unaerated diazo and photoautorophic cultures of the cyanobacterium Anabaena torulosa induced early development of akinetes with high frequency. When cultures under any mode of nutrition were aerated, akinetes were not differentiated. Unaerated cultures with nitrate nitrogen or fructose exhibited higher respiratory rates and nitrogen assimilation compared to aerated cultures. This was evidenced by increased respiratory O2 uptake and high activities of pyruvate kinase, malate dehydrogenase (NAD+), nitrogenase and nitrate reductase signifying that akinete forming unaerated cultures exhibited high carbon dissimilation and nitrogen assimilation resulting in high nitrogenous build up in the cells. Aerated, non‐akinete cultures, on the other hand, were associated with low respiratory O2 uptake, low pyruvate kinase and malate dehydrogenase (NAD+) activities, suggesting that carbon dissimilation was not favoured either in presence of nitrate or fructose. Moreover, higher activity of NADP+ linked malate dehydrogenase and lower nitrate reductase activity in aerated cultures led to a high carbon and low nitrogen content of the cells resulting in high cellular C:N ratio. The results suggest that interaction between carbon and nitrogen metabolism regulates akinete development in A. torulosa. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Corrosion behavior of composite brake materials
Authors: Jia Xian , Ling Ruo‐Fei , Chen Da‐Lu 
Published: March 2008

AbstractIt is very important to study the corrosion behavior of composite brake materials for their design, manufacture, and application. In the study, one kind of composite brake material used in engineering machinery, two kinds used in automobiles, and gray cast iron HT200 were selected as tested materials. Their corrosion behavior in typical acid solution, alkali solution, salt solution, running water, and air were investigated. The results showed that some components of composite brake materials, such as iron matrix, steel fiber, and iron powder, were easily subject to corrosion in acid solution. Corrosive pitting, net‐like cracking, and breakage appeared at their corrosion surfaces, and in the solution of 3.5% NaCl, corrosive pitting took place and corrosion holes of 2–8 µm diameter formed at the corrosion surface of these components. But when brake materials were exposed to the solution of 5% NaOH, the organic binder was corroded seriously, nearly parallel cracks formed at the corrosion surface and some samples even became loose powders because the corrosion makes the binder lose its adhering function. In running water and air, the tested samples have an excellent corrosion resistance, and the composite brake material containing organic binder has a better corrosion resistance compared with other tested materials. The investigation has also indicated that the interface between ingredients easily corrodes.
Phosphorus‐Containing Sulfonated Polyimides for Proton Exchange Membranes
Authors: Çakir Mustafa , Karataş Sevim , Menceloğlu Yusuf , Kayaman‐Apohan Nilhan , Güngör Atilla 
Published: March 2008

AbstractSynthesis and characterization of the novel sulfonated BAPPO monomer and its use in the synthesis of a new phosphine oxide‐based sulfonated polyimide are described. BTDA, 6FDA, and DDS were used as monomers in the polyimide synthesis. Sulfonated polyimide membranes were obtained by a solution thermal imidization method. The thermal behavior of the polymers was investigated by DSC and TGA. The morphological structure of the membranes was investigated by tapping‐mode AFM. The proton conductivities of the sulfonated polyimide increased regularly as a function of sulfonated diamine content. The conductivities are good compared to typical proton exchange membranes.magnified image
Polyester Wire Enamels ‐ Reliable Coatings in the Wire Industry from the Beginning to Nowadays
Authors: Bhanu Vinayak A. 
Published: March 2008

AbstractElectric power needs to be used with prudence. Generation and transport of electric power requires insulated wires as “primary” conductors. The insulation on bare metal consists of thermosetting polymers. This review article discusses the synthesis and applications of heat cured polyester resins that are used in “primary insulation” industry. These are commonly called polyester wire enamels and they have been the work horse of this industry for past several decades. The article focuses on the developments over the past twenty years in the polymer synthesis of these polyester resins. An attempt has been also made to briefly discuss the various curing methods and their limitations.The anticipated trends of further developments in this field of research are presented. The review is hoped to fill in the gap between the active research in this specialty area and its insuffcient coverage in the main stream polymer chemistry since most of the progress is available only in patents form.magnified image