bluuebunny/crossref_metadata_2025_split huggingface dataset:
Feasibility of dynamic susceptibility contrast perfusion MR imaging at 3T using a standard quadrature head coil and eight‐channel phased‐array coil with and without SENSE reconstruction
Authors: Lupo Janine M. , Lee Michael C. , Han Eric T. , Cha Soonmee , Chang Susan M. , Berger Mitchel S. , Nelson Sarah J. 
Published: August 2006

AbstractPurposeTo investigate changes in image and dynamic signal‐to‐noise ratios (SNRs) of the ΔR2* curve, as well as magnetic susceptibility‐induced artifacts between a standard quadrature head coil and an eight‐channel phased‐array coil with and without sensitivity‐encoding (SENSE) at 3T, compared to the current clinical standard head coil acquisition at 1.5T.Materials and MethodsDynamic susceptibility contrast (DSC) perfusion MRI was performed on 80 brain tumor patients using a gradient‐echo, echo‐planar imaging (EPI) sequence. Image and dynamic SNR were compared between 1.5T and 3T field strengths, a quadrature and eight‐channel phased‐array coil, and a conventional vs. partially parallel EPI acquisition with SENSE reconstruction. The amount of geometric distortion and signal dropout was quantified and compared between conventional and SENSE EPI acquisitions within the same exam at 3T.ResultsAn initial 2.6‐fold elevation in dynamic SNR was observed in normal‐appearing white matter when doubling the field strength (P < 0.001), with an additional 1.7‐fold increase found when employing an eight‐channel phased‐array coil (P < 0.002). Compared to the standard 3T eight‐channel coil acquisition, the implementation of SENSE reduced the number of voxels experiencing large anterior shifts in the phase‐encode direction, lowered the volume of signal dropout by 2.0–11.5%, and allowed a 1.4‐fold increase in slice coverage, while only decreasing the dynamic SNR by 22%.ConclusionSENSE EPI at 3T yielded a significant improvement in dynamic SNR over the 1.5T acquisitions. A significant reduction in magnetic susceptibility‐induced artifacts was achieved with SENSE EPI compared to the standard EPI eight‐channel coil acquisition at 3T. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Hyperintense nodules on non‐enhanced T1‐weighted gradient‐echo magnetic resonance imaging of cirrhotic liver: Fate and clinical implications
Authors: Yu Jeong‐Sik , Lee Jei Hee , Park Mi‐Suk , Kim Ki Whang 
Published: August 2006

AbstractPurposeTo investigate the fate of hyperintense hepatic nodules on nonenhanced T1‐weighted (T1w) gradient‐echo (GRE) magnetic resonance (MR) images in cirrhotic patients.Materials and MethodsA total of 79 cirrhotic patients with hyperintense nodules (>5 mm) on precontrast opposed‐phase (repetition time (TR)/echo time (TE) = 140/2.7 msec) GRE images from initial MRI without T2‐weighted (T2w) hyperintensity or arterial hypervascularity were subjected to analysis of subsequent MR images obtained at intervals of 12–56 months (mean = 24.5 months). Multiplicity of hyperintense nodules (group A, up to 8; group B, >8) was correlated with follow‐up changes.ResultsGroup B patients were younger (P = 0.003) than group A patients (mean = 47.5 and 56.2 years, respectively). In 66 group A patients, 39 out of 143 lesions (27%) were enlarged, including 20 malignantly transformed or borderline lesions. Of the 104 lesions (the eight largest lesions in each patient) in 13 group B patients, only three (2.9%) were enlarged. The results of best‐ and worst‐case analyses showed that overall the lesions were benign in 91% and 82% of patients, respectively.ConclusionT1w hyperintense nodules without T2w hyperintensity or arterial hypervascularity in the cirrhotic liver are benign in most cases. In younger patients with numerous macronodules, almost all of these lesions follow a benign course. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Focal Wallerian degeneration of the corpus callosum in large middle cerebral artery stroke: Serial diffusion tensor imaging
Authors: Gupta Rakesh K. , Saksena Sona , Hasan Khader M. , Agarwal Atul , Haris Mohammad , Pandey Chandra M. , Narayana Ponnada A. 
Published: August 2006

AbstractPurposeTo detect lesion‐related focal Wallerian degeneration (WD) changes in different segments of the corpus callosum (CC) in patients with large middle cerebral arterial (MCA) territory stroke using diffusion tensor imaging (DTI).Materials and MethodsEight patients underwent DTI scans at three different time points: six to eight weeks, 10–12 weeks, and beyond six months of stroke onset. Eight healthy age‐matched controls were also scanned using the same protocol at three different time points. Region‐of‐interest (ROI) analysis was performed on seven segments of the CC to determine the fractional anisotropy (FA), mean diffusivity (MD), and corresponding callosal cross‐sectional areas.ResultsOn repeated‐measures analysis of variance (ANOVA), a significant reduction in the FA values was observed from the first to the third study compared to controls, reflecting temporal degeneration in the rostrum, genu, rostral body, anterior midbody, and splenium of the CC. However, a significant temporal elevation in MD values was observed in only the rostral body and anterior midbody of the CC. This was associated with a significant region‐specific reduction in the cross‐sectional areas at time points beyond six months, and appears to be consistent with the loss of callosal structural components due to interruption of the cortico‐callosal fibers secondary to WD.ConclusionThese results indicate that cortico‐callosal topographical changes exhibit a significant temporal decline in observed FA values that is suggestive of cortico‐callosal WD in patients with large MCA territory stroke. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Evaluation of hepatic lesions and hepatic parenchyma using diffusion‐weighted echo‐planar MR with three values of gradient b‐factor
Authors: Moteki Takao , Horikoshi Hiroyuki 
Published: August 2006

AbstractPurposeTo determine whether diffusion‐weighted echo‐planar (EP) MR images with very small, small, and large gradient b‐factors are useful in evaluating hepatic lesions and hepatic parenchyma.Materials and MethodsApproximate values of the apparent diffusion coefficients for diffusion (D) and for flowing spins (D*) for 96 hepatic lesions (26 hepatocellular carcinomas [HCCs], 28 metastases, 26 hemangiomas, and 16 cysts) and the non‐lesion‐bearing regions of parenchyma in 78 livers (50 noncirrhotic and 28 cirrhotic) were calculated from EP images (modified for gradient b‐factors of 3, 50, and 300 second/mm2).ResultsLiver cysts and noncirrhotic livers showed statistically higher mean D* values than HCCs, hemangiomas, metastases, and cirrhotic livers (P < 0.05 on Scheffé post hoc analysis). Liver cysts showed statistically higher mean D values than HCCs, metastases, noncirrhotic livers, and cirrhotic livers (P < 0.05). Liver hemangiomas showed statistically higher mean D values than HCCs, noncirrhotic livers, and cirrhotic livers (P < 0.05).ConclusionThe D* value in addition to the D value may be useful for evaluating the nature of diffusion and flowing spins in hepatic lesions and hepatic parenchyma. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Identification of microbial mixtures by LC‐selective proteotypic‐peptide analysis(SPA)
Authors: Lo Alan A.‐L. , Hu Anren , Ho Yen‐Peng 
Published: August 2006

AbstractThis paper describes a method—using a combination of LC‐MS/MS of selected bacteria‐specific peptides and database search—for determining the species of bacteria present in a mixture. We identified the proteotypic peptides that were associated with specific bacteria by searching protein databases for the LC‐MS/MS data. The retention time windows for specific peptide markers were used as an extra constraint so that the peptide markers of many bacterial species could be analyzed in a single LC‐selective proteotypic‐peptide analysis (SPA). We performed LC‐MS/MS analyses on the proteolytic digest of cell extracts and monitored only the selected marker peptide ions at given elution time windows. The corresponding bacterial species could be characterized when the selected peptides that eluted at expected elution windows were identified correctly from the database. We managed to identify up to eight bacterial species simultaneously during a single LC‐MS/MS analysis, as well as bacteria mixed in various abundances. Two marker ions having similar values of m/z, but obtained from two different bacterial samples, which would otherwise be selected as precursors within mass tolerance and would complicate the MS/MS data, were time‐resolved using LC and then used to correctly identify their bacterial sources. The coupling of selective MS/MS monitoring with separation methods, such as LC, provides a highly selective and accurate analytical method for characterizing complex mixtures of bacterial species. Copyright © 2006 John Wiley & Sons, Ltd.
Mass spectrometry assisted assignments of binding and cleavage sites of copper(II) and platinum(II) complexes towards oxidized insulin B chain
Authors: Hong Jin , Miao Ren , Zhao Chunmei , Jiang Jiang , Tang Huiwei , Guo Zijian , Zhu Longgen 
Published: August 2006

AbstractInteraction of cis‐[Pt(en)(H2O)2]2+ and [CuL(H2O)]2+, where L is 2‐[bis(2‐aminoethyl)amino]ethanol, with oxidized insulin B chain in molar ratio of 1 : 1, 1 : 2 and 1 : 3 at pH 2.5 and 40 °C has been investigated by electrospray ionization mass spectrometry (ESI‐MS) and tandem mass spectrometry (MS/MS). The results show that the binding sites of the two complexes with oxidized insulin B chain are terminal NH2, imidazole groups of His5 and His10. The hydrolytic cleavage studies show that the [CuL(H2O)]2+, upon a pendant hydroxyl group of the ligand, selectively cleaves the peptide bonds at Gly8–Ser9, Asn3–Gln4 and Phe1–Val2, and the cis‐[Pt(en)(H2O)2]2+ only cleaves the peptide bond at His10–Leu11. This is the first report of cis‐[Pt(en)(H2O)2]2+‐promoted cleavage of His–X peptide bond. Copyright © 2006 John Wiley & Sons, Ltd.
Diastereomeric differentiation of peptides with CuII and FeII complexation in an ion trap mass spectrometer
Authors: Lagarrigue Mélanie , Bossée Anne , Afonso Carlos , Fournier Françoise , Bellier Bruno , Tabet Jean‐Claude 
Published: August 2006

AbstractComplexation by transition metal ions (CuII and FeII) was successfully used to differentiate the diastereomeric YAGFL, YDAGFL and YDAGFDL pentapeptides by electrospray ionization‐ion trap mass spectrometry in the positive ion mode using low‐energy collision conditions. This distinction was allowed by the stereochemical effects due to the (D)Leu/(L)Leu and the (D)Ala/(L)Ala residues yielding various steric interactions which direct relative dissociation rate constants of the binary [(M − H) + MeII]+ complexes (Me = Cu or Fe) subjected to low‐energy, collision‐induced dissociation processes. The interpretation of the collision‐induced dissociation spectra obtained from the diastereomeric cationized peptides allowed the location of the deprotonated site(s), leading to the postulation of ion structures and fragmentation pathways for both the [(M − H) + CuII]+ and [(M − H) + FeII]+ complexes, which differed significantly. With CuII, consecutive fragmentations, initiated by the decarboxylation at C‐terminus, were favored relative to sequence product ions. On the other hand, with FeII, competitive fragmentations resulting in abundant sequence product ions and significant internal losses were preferred. This could be explained by different localizations of the negative charge, which directs the orientation of both the [(M − H) + CuII]+ and [(M − H) + FeII]+ binary complexes fragmentations. Indeed, the free negative charge of the [(M − H) + CuII]+ ions was mainly located at one oxygen atom: either at the C‐terminal carboxylic group or, to a minor extent, at the Tyr phenol group (i.e. zwitterionic forms). On the other hand, the negative charge of the [(M − H) + FeII]+ ions was mainly located at one of the nitrogen atoms of the peptide backbone and coordinated to FeII (i.e. salt non‐zwitterionic form).Moreover, this study reveals the particular behavior of CuII reduced to CuI, which promotes radical losses not observed from the peptide–FeII complexes. Finally, this study shows the analytical potentialities of the complexation of transition metal ions with peptides providing structural information complementary to that obtained from low‐energy, collision‐induced dissociation processes of protonated or deprotonated peptides. Copyright © 2006 John Wiley & Sons, Ltd.
Mass spectrometric characterization of covalent modification of human serum albumin by 4‐hydroxy‐trans‐2‐nonenal
Authors: Aldini Giancarlo , Gamberoni Luca , Orioli Marica , Beretta Giangiacomo , Regazzoni Luca , Maffei Facino Roberto , Carini Marina 
Published: August 2006

AbstractSeveral pieces of evidence indicate that albumin modified by HNE is a promising biomarker of systemic oxidative stress and that HNE‐modified albumin may contribute to the immune reactions triggered by lipid peroxidation‐derived antigens. In this study, we found by HPLC analysis that HNE is rapidly quenched by human serum albumin (HSA) because of the covalent adduction to the different accessible nucleophilic residues of the protein, as demonstrated by electrospray ionization mass spectrometry (ESI‐MS) direct infusion experiments (one to nine HNE adducts, depending on the molar ratio used, from 1 : 0.25 to 1 : 5 HSA : HNE). An LC‐ESI‐MS/MS approach was then applied to enzymatically digested HNE‐modified albumin, which permitted the identification of 11 different HNE adducts, 8 Michael adducts (MA) and 3 Schiff bases (SB), involving nine nucleophilic sites, namely: His67 (MA), His146 (MA), His242 (MA), His288 (MA), His510 (MA), Lys 195 (SB), Lys 199 (MA, SB), Lys525 (MA, SB) and Cys34 (MA). The most reactive HNE‐adduction site was found to be Cys34 (MA) followed by Lys199, which primarily reacts through the formation of a Schiff base, and His146, giving the corresponding HNE Michael adduct. These albumin modifications are suitable tags of HNE‐adducted albumin and could be useful biomarkers of oxidative and carbonylation damage in humans. Copyright © 2006 John Wiley & Sons, Ltd.
Structure elucidation of cyclic pyoverdins and examination of rearrangement reactions in MS/MS experiments by determination of exact product ion masses
Authors: Schäfer Mathias , Fuchs Regine , Budzikiewicz Herbert , Springer Andreas , Meyer Jean‐Marie , Linscheid Michael 
Published: August 2006

AbstractStructure elucidation of naturally occurring linear and cyclic peptidic compounds can be complicated by rearrangement reactions induced upon collision activation (CA) when parts of the molecule migrate, suggesting incorrect substitution patterns. Such complex rearrangements are examined and discussed for two iron complexing compounds produced by the bacterial genus Pseudomonas (so‐called pyoverdins). Various MS2‐ and MS3‐product ion experiments were performed using a quadrupole‐ion trap (QIT) at low resolution and a FT‐ICR at high resolution allowing accurate mass determinations. The results of the multidimensional study confirm the proposed processes. On the basis of the series of tandem‐MS experiments the structure of a new pyoverdin from a P. fluorescens strain [PVD(D47)] is deduced. Copyright © 2006 John Wiley & Sons, Ltd.
Climatic outliers
Authors: Hunt B. G. 
Published: August 2006

AbstractA 10 000‐year simulation for ‘present’ climate has been generated with the CSIRO Mark 2 coupled climatic model. In this paper the model output has been analysed to produce a climatology of climatic outliers and to assess the role of such outliers in climatic variability. An assessment of the frequency of occurrence of outliers, compared with the statistical expectation from a Gaussian distribution, indicates that over most of the globe the surface temperature conforms to this distribution, but this is not the case for rainfall. Among the issues considered are the spatial occurrence rates over the globe of normalised climatic anomalies of various magnitudes, the temporal variability of outliers, the seasonal variability for a given outlier year, the spatial characteristics of outliers and the question of precursors to outliers. The relationship of outliers to the El Niño/Southern Oscillation, the Pacific Decadal Oscillation and the North Atlantic Oscillation is also considered. A case study examining the relative severities of an outlier drought to a severe drought is also undertaken. Finally, the role of outliers and the greenhouse effect is considered. It is concluded that outliers are a manifestation of stochastic forcing. Copyright © 2006 Royal Meteorological Society.
Plant‐oil‐based lubricants and hydraulic fluids
Authors: Schneider Manfred P 
Published: August 2006

AbstractIt is estimated that, at present, approximately 50% of all lubricants sold worldwide end up in the environment via total loss applications, volatility, spills or accidents. More than 95% of these materials are currently mineral oil based. In view of their high ecotoxicity and low biodegradability, mineral oil‐based lubricants constitute a considerable threat to the environment. In contrast, most lubricants and hydraulic fluids based on plant oils are rapidly and completely biodegradable and are of low ecotoxicity; moreover, lubricants based on plant oils display excellent tribological properties and generally have very high viscosity indices and flashpoints. However, in order to compete with mineral‐oil‐based products, some of their inherent disadvantages must be corrected, such as their sensitivity to hydrolysis and oxidative attack, and their behaviour at low temperatures. Various methods to improve the undesirable properties of native plant oils will be discussed. In parallel, government regulations that encourage or enforce the use of bio‐based fluids, at least in ecologically sensitive areas, will help to increase their market share. Using the numerous possibilities for selective breeding and/or chemical improvement of the double bond systems of natural fatty acids by increased R&D, the major obstacles regarding the use of plant‐based raw materials for the production of lubricant base fluids can be overcome and bio‐based fluids should expect a future with increasing market shares. Copyright © 2006 Society of Chemical Industry
Solubility measurement of methyl anthranilate in supercritical carbon dioxide using dynamic and static equilibrium systems
Authors: Tsai Wen‐Chyan , Ruan Yonghong , Rizvi Syed SH 
Published: August 2006

AbstractThe solubility of methyl anthranilate in supercritical carbon dioxide was determined using dynamic and static equilibrium systems. Three temperatures (40, 60 and 80 °C) and a pressure range between 160 and 340 atm were applied for the dynamic solubility measurements. The flow rate was maintained at 0.5 mL min−1 in the dynamic solubility measurements, where the solute solubility was claimed to be independent of the flow‐rate factor. Two temperatures (40 and 60 °C) and the pressure range between 100 and 265 atm were used in the static equilibrium system. The crossover pressure region was observed between 220 and 240 atm in the static system, but was not seen in the dynamic system. The solubility of methyl anthranilate determined by the static system was consistently higher than the dynamic solubility measurement, indicating that the static technique provided more reliable solubility data for methyl anthranilate than the dynamic technique. The solubility data obtained with the static system were in good agreement with the predictive models based on the Chrastil equation and the Peng–Robinson equation of state with the Panagiotopoulos and Reid mixing rule. Copyright © 2006 Society of Chemical Industry
In vitro bioavailability of calcium and iron from selected green leafy vegetables
Authors: Gupta Sheetal , Lakshmi A Jyothi , Prakash Jamuna 
Published: August 2006

AbstractThe objective of the present investigation was to analyze the relative influence of oxalic acid, phytic acid, tannin and dietary fiber on in vitro availability of iron and calcium from green leafy vegetables (GLV). Thirteen GLV were selected and analyzed for iron, calcium, oxalic acid, phytic acid, tannin and dietary fiber contents using standard methods. The bioavailability of calcium and iron in the GLV was estimated by equilibrium dialysis. Oxalic acid content was less than 1 g kg−1 in four greens and ranged between 1.22 to 11.98 g kg−1 in the remaining. Dietary fiber ranged from 19.5 to 113.7 g kg−1. Tannin content ranged between 0.6138 and 2.1159 g kg−1 with the exception of two GLV that had 0.1332 and 14.8619 g kg−1. Four GLV were found to have approximately 40% bioavailable iron, while the others were in the range of 6–30%. In vitro available calcium was less than or equal to 25% in eight GLV and between 34% and 52% in five GLV. Multiple regression analysis revealed that these factors together accounted for 53% (r2 = 0.53) and 45% (r2 = 0.45) inhibition of iron and calcium absorption, respectively. These findings infer that calcium and iron availability is influenced by the constituents present in the GLV. Copyright © 2006 Society of Chemical Industry
Effect of ozone and calcium lactate treatments on browning and texture properties of fresh‐cut lettuce
Authors: Rico Daniel , Martín‐Diana Ana Belen , Frías Jesus M , Henehan Gary TM , Barry‐Ryan Catherine 
Published: August 2006

AbstractThe effects of three treatments, 1 mg L−1 ozone at 18–20 °C, 15 g L−1 calcium lactate (CLac) at 50 °C and a combination thereof, were compared on fresh‐cut lettuce over 10 days of refrigerated storage. Respiration rate, browning and texture were examined as main quality indicators. The use of ozone produced a significantly (P < 0.05) higher oxygen decline than the use of CLac (from day 3 to day 10). At the end of storage, CLac (alone or combined with ozone) samples had higher oxygen content (∼9%) than ozone samples (∼6%). Enzymatic activity decreased significantly (P < 0.05) in ozone samples. Polyphenol oxidase activity in fresh‐cut lettuce treated with ozone (alone or combined with CLac) showed lower values on day 1 (<2500 units g−1) and at the end of storage (<3000 units g−1) than CLac samples (4000–4800 units g−1). Ozone also reduced peroxidase activity to ∼300 units g−1 after treatment. Finally, pectin methylesterase activity was also reduced with ozone, showing a negative effect on textural properties. Data suggested that CLac maintained quality markers better than treatments with ozone and ozone/CLac combination over 10 days of storage. Copyright © 2006 Society of Chemical Industry
Sixty years of EHL
Authors: Spikes H. A. 
Published: August 2006

AbstractIt is now 60 years since Ertel produced the first solution to the elastohydrodynamic lubrication (EHL) problem. There has been enormous progress since then, both in numerical modelling and in experimental research on EHL. The moving, rough surface EHL problem can now be solved on laptop‐level computers, while maps of film thickness, pressure and temperature can be obtained experimentally from within rolling/sliding contacts. However, there remain some important questions that have not been fully resolved. One of the most contentious is how to describe the rheological properties of lubricants under the very severe conditions present in thin film EHL contacts. A second is how to model mixed lubricated contact, where the fluid film can break down at asperity conjunctions. But perhaps the greatest challenge to researchers in EHL is to produce useful design equations for predicting the performance of machine components operating in EHL and thereby ensure that EHL theory becomes an integral part of the design process. Copyright © 2006 John Wiley & Sons, Ltd.