bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative mapping of T2 using partial spoiling
Authors: Bieri Oliver , Scheffler Klaus , Welsch Goetz H. , Trattnig S. , Mamisch Tallal C. , Ganter Carl 
Published: March 2011

AbstractFast quantitative MRI has become an important tool for biochemical characterization of tissue beyond conventional T1, T2, and T2*‐weighted imaging. As a result, steady‐state free precession (SSFP) techniques have attracted increased interest, and several methods have been developed for rapid quantification of relaxation times using steady‐state free precession. In this work, a new and fast approach for T2 mapping is introduced based on partial RF spoiling of nonbalanced steady‐state free precession. The new T2 mapping technique is evaluated and optimized from simulations, and in vivo results are presented for human brain at 1.5 T and for human articular cartilage at 3.0 T. The range of T2 for gray and white matter was from 60 msec (for the corpus callosum) to 100 msec (for cortical gray matter). For cartilage, spatial variation in T2 was observed between deep (34 msec) and superficial (48 msec) layers, as well as between tibial (33 msec), femoral, (54 msec) and patellar (43 msec) cartilage. Excellent correspondence between T2 values derived from partially spoiled SSFP scans and the ones found with a reference multicontrast spin‐echo technique is observed, corroborating the accuracy of the new method for proper T2 mapping. Finally, the feasibility of a fast high‐resolution quantitative partially spoiled SSFP T2 scan is demonstrated at 7.0 T for human patellar cartilage. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Measurement of glycine in the human brain in vivo by 1H‐MRS at 3 T: application in brain tumors
Authors: Choi Changho , Ganji Sandeep K. , DeBerardinis Ralph J. , Dimitrov Ivan E. , Pascual Juan M. , Bachoo Robert , Mickey Bruce E. , Malloy Craig R. , Maher Elizabeth A. 
Published: March 2011

AbstractGlycine is a key metabolic intermediate required for the synthesis of proteins, nucleic acids, and other molecules, and its detection in cancer could, therefore, provide biologically relevant information about the growth of the tumor. Here, we report measurement of glycine in human brain and gliomas by an optimized point‐resolved spectroscopy sequence at 3 T. Echo time dependence of the major obstacle, myo‐inositol (mI) multiplet, was investigated with numerical simulations, incorporating the 3D volume localization. The simulations indicated that a subecho pair (TE1, TE2) = (60, 100) ms permits detection of both glycine and mI with optimum selectivity. In vivo validation of the optimized point‐resolved spectroscopy was conducted on the right parietal cortex of five healthy volunteers. Metabolite signals estimated from LCModel were normalized with respect to the brain water signal, and the concentrations were evaluated assuming the total creatine concentration at 8 mM. The glycine concentration was estimated as 0.6 ± 0.1 mM (mean ± SD, n = 5), with a mean Cramér‐Rao lower bound of 9 ± 1%. The point‐resolved spectroscopy sequence was applied to measure the glycine levels in patients with glioblastoma multiforme. Metabolite concentrations were obtained using the water signal from the tumor mass. The study revealed that a subset of human gliomas contains glycine levels elevated 1.5–8 fold relative to normal. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Diffusion characteristics associated with neuronal injury and glial activation following hypoxia‐ischemia in the immature brain
Authors: Lodygensky Gregory A. , West Tim , Moravec Matthew D. , Back Stephen A. , Dikranian Krikor , Holtzman David M. , Neil Jeffrey J. 
Published: March 2011

AbstractTo identify quantitative MRI indices of injury in the brain following neonatal hypoxic‐ischemic brain injury, we subjected mouse pups to hypoxia‐ischemia on postnatal day 7 and obtained conventional and diffusion‐weighted in vivo images of the brain 24 h later followed by histological assessment. T2‐weighted images showed increased signal intensity in the CA1 and CA2 regions of the hippocampus ipsilateral to the injury and adjacent white matter. In contrast, diffusion imaging showed reduced apparent diffusion coefficient (ADC) values in CA1 and CA2, but increased values in the adjacent white matter. Histological analysis showed widespread gliosis with degenerating oligodendrocytes in the ipsilateral hippocampus. In addition, white matter areas that were abnormal by MRI showed an increase in the number of activated microglia (CD45 positive cells). Activated caspase‐3 immunostaining showed a marked increase in neurons in the hippocampal regions corresponding to those with reduced ADC, and a quantitative measure of staining showed a statistically significant correlation with the ADC. In contrast, ADC was higher in adjacent white matter, where histology showed activation of microglia and reactive oligodendrocytes but not caspase‐3 activation. These results suggest that the ADC response differs between areas of neuronal injury as compared with those showing glial changes without marked cell death. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
A measurement setup for direct 17O MRI at 7 T
Authors: Hoffmann Stefan H. , Begovatz Paul , Nagel Armin M. , Umathum Reiner , Schommer Kai , Bachert Peter , Bock Michael 
Published: March 2011

AbstractAn efficient breathing system was designed for direct 17O MRI to perform oxygen metabolism studies of the human brain. The breathing system consists of a demand oxygen delivery device for 17O2 supply and a custom‐built re‐breathing circuit with pneumatic switching valve. To efficiently deliver the 17O gas to the alveoli of the lungs, the system applies short gas pulses upon an inspiration trigger via a nasal cannula. During and after 17O2 administration, the exhaled gas volumes are stored and filtered in the re‐breathing section to make the most efficient use of the rare 17O gas. In an inhalation experiment, 2.2 ± 0.1 L of 70%‐enriched 17O2 were administered to a healthy volunteer and direct 17O MRI was performed for a total imaging time of 38 min with a temporal resolution of 50 s per 3D data set. Mapping of the maximum signal increase was carried out showing regional variations of oxygen concentration of up to 30% over the natural abundance of 17O water. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
k‐t group sparse: A method for accelerating dynamic MRI
Authors: Usman M. , Prieto C. , Schaeffter T. , Batchelor P. G. 
Published: March 2011

AbstractCompressed sensing (CS) is a data‐reduction technique that has been applied to speed up the acquisition in MRI. However, the use of this technique in dynamic MR applications has been limited in terms of the maximum achievable reduction factor. In general, noise‐like artefacts and bad temporal fidelity are visible in standard CS MRI reconstructions when high reduction factors are used. To increase the maximum achievable reduction factor, additional or prior information can be incorporated in the CS reconstruction. Here, a novel CS reconstruction method is proposed that exploits the structure within the sparse representation of a signal by enforcing the support components to be in the form of groups. These groups act like a constraint in the reconstruction. The information about the support region can be easily obtained from training data in dynamic MRI acquisitions. The proposed approach was tested in two‐dimensional cardiac cine MRI with both downsampled and undersampled data. Results show that higher acceleration factors (up to 9‐fold), with improved spatial and temporal quality, can be obtained with the proposed approach in comparison to the standard CS reconstructions. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Assessment of glycosaminoglycan distribution in human lumbar intervertebral discs using chemical exchange saturation transfer at 3 T: feasibility and initial experience
Authors: Kim Mina , Chan Queenie , Anthony Marina‐Portia , Cheung Kenneth M.C. , Samartzis Dino , Khong Pek‐Lan 
Published: March 2011

AbstractRecent studies have proposed that glycosaminoglycan chemical exchange saturation transfer (gagCEST) is associated with a loss of glycosaminoglycans (GAGs), which may be an initiating factor in intervertebral disc (IVD) degeneration. Despite its promising potential, this application has not been reported in human in vivo IVD studies because of the challenges of B0 magnetic field inhomogeneity in gagCEST. This study aimed to evaluate the feasibility of quantifying CEST values in IVDs of healthy volunteers using a clinical 3 T scanner. A single‐slice turbo spin echo sequence was used to quantify the CEST effect in various GAG phantoms and in IVDs of 12 volunteers. The phantom results indicated high correlation between gagCEST and GAG concentrations (R2 = 0.95). With optimal B0 inhomogeneity correction, in vivo CEST maps of IVDs showed robust contrast between the nucleus pulposus (NP) and the annulus fibrosus (AF) (p < 0.01), as well as higher signal in the central relative to the peripheral NP. In addition, a trend of decreasing CEST values from upper to lower disc levels was evident in NP. Our results demonstrate that in vivo gagCEST quantification in human lumbar IVDs is feasible at 3 T in combination with successful B0 inhomogeneity correction, but without significant hardware modifications. Our initial findings suggest that it would be worthwhile to perform direct correlation studies between CEST and GAGs using cadaver samples, and to extend this novel technique to studies on patients with degenerative discs to better understand its distinct imaging features relative to conventional techniques. Copyright © 2011 John Wiley & Sons, Ltd.
Numerical solution of a linear elliptic partial differential equation with variable coefficients: A complex variable boundary element approach
Authors: Ang Whye‐Teong 
Published: March 2011

AbstractThis article presents a complex variable boundary element method for the numerical solution of a second order elliptic partial differential equation with variable coefficients. To assess the validity and accuracy of the method, it is applied to solve some specific problems with known solutions. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011
The effect of attending full‐day kindergarten on English learner students
Authors: Cannon Jill S. , Jacknowitz Alison , Painter Gary 
Published: March 2011

AbstractA significant and growing English learner (EL) population attends public schools in the United States. Evidence suggests they are at a disadvantage when entering school and their achievement lags behind non‐EL students. Some educators have promoted full‐day kindergarten programs as especially helpful for EL students. We take advantage of the large EL population and variation in full‐day kindergarten implementation in the Los Angeles Unified School District to examine the impact of full‐day kindergarten on academic achievement, retention, and English language fluency using difference‐in‐differences models. We do not find signficant effects of full‐day kindergarten on most academic outcomes and English fluency through second grade. However, we find that EL students attending full‐day kindergarten were 5 percentage points less likely to be retained before second grade and there are differential effects for several outcomes by student and school characteristics. © 2011 by the Association for Public Policy Analysis and Management.
Do data breach disclosure laws reduce identity theft?
Authors: Romanosky Sasha , Telang Rahul , Acquisti Alessandro 
Published: March 2011

AbstractIn the United States, identity theft resulted in corporate and consumer losses of $56 billion dollars in 2005, with up to 35 percent of known identity thefts caused by corporate data breaches. Many states have responded by adopting data breach disclosure laws that require firms to notify consumers if their personal information has been lost or stolen. Although the laws are expected to reduce identity theft, their effect has yet to be empirically measured. We use panel data from the U.S. Federal Trade Commission to estimate the impact of data breach disclosure laws on identity theft from 2002 to 2009. We find that adoption of data breach disclosure laws reduce identity theft caused by data breaches, on average, by 6.1 percent. © 2011 by the Association for Public Policy Analysis and Management.
Rpl27a mutation in the sooty foot ataxia mouse phenocopies high p53 mouse models
Authors: Terzian Tamara , Dumble Melissa , Arbab Farinaz , Thaller Christina , Donehower Lawrence A , Lozano Guillermina , Justice Monica J , Roop Dennis R , Box Neil F 
Published: March 2011

AbstractRibosomal stress is an important, yet poorly understood, mechanism that results in activation of the p53 tumour suppressor. We present a mutation in the ribosomal protein Rpl27a gene (sooty foot ataxia mice), isolated through a sensitized N‐ethyl‐N‐nitrosourea (ENU) mutagenesis screen for p53 pathway defects, that shares striking phenotypic similarities with high p53 mouse models, including cerebellar ataxia, pancytopenia and epidermal hyperpigmentation. This phenocopy is rescued in a haploinsufficient p53 background. A detailed examination of the bone marrow in these mice identified reduced numbers of haematopoietic stem cells and a p53‐dependent c‐Kit down‐regulation. These studies suggest that reduced Rpl27a increases p53 activity in vivo, further evident with a delay in tumorigenesis in mutant mice. Taken together, these data demonstrate that Rpl27a plays a crucial role in multiple tissues and that disruption of this ribosomal protein affects both development and transformation. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Classical complement activation as a footprint for murine and human antiphospholipid antibody‐induced fetal loss
Authors: Cohen Danielle , Buurma Aletta , Goemaere Natascha N , Girardi Guillermina , le Cessie Saskia , Scherjon Sicco , Bloemenkamp Kitty WM , de Heer Emile , Bruijn Jan A , Bajema Ingeborg M 
Published: March 2011

AbstractRecurrent miscarriage, fetal growth restriction and intrauterine fetal death are frequently occurring complications of pregnancy in patients with systemic lupus erythaematosus (SLE) and antiphospholipid syndrome (APS). Murine models show that complement activation plays a pivotal role in antiphospholipid antibody‐mediated pregnancy morbidity, but the exact pathways of complement activation and their potential role in human pregnancy are insufficiently understood. We hypothesized that the classical pathway would play a major role in inducing fetal loss. Pregnant C57BL/6 mice and mice deficient in C1q and factor D were injected with antiphospholipid antibodies or normal human IgG. Mouse placentas were subsequently stained with an anti‐C4 antibody and anti‐normal human IgG to determine the presence of classical complement activation and IgG binding. Findings in mice were validated in 88 human placentae from 83 women (SLE and APS cases versus controls), which were immunohistochemically stained for C4d, C1q, properdin and MBL. Staining patterns were compared to pregnancy outcome. In murine placentae of mice pretreated with antiphospholipid antibodies, increased C4 deposition was observed, which was associated with adverse fetal outcome but not with IgG binding. In humans, diffuse C4d staining at the feto–maternal interface was present almost exclusively in patients with SLE and/or APS (p < 0.001) and was related to intrauterine fetal death (p = 0.03). Our data show that presence of C4d in murine and human placentae is strongly related to adverse fetal outcome in the setting of SLE and APS. The excessive deposition of C4d supports the concept of severe autoantibody‐mediated injury at the fetal–maternal interface. We suggest C4d as a potential biomarker of autoantibody‐mediated fetal loss in SLE and APS. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Effect of vapor‐grown carbon nanofibers on the sliding friction of natural rubber composites
Authors: Jiang Hong‐Xia , Ni Qing‐Qing , Natsuki Toshiaki , Yamamoto Yutaka 
Published: March 2011

AbstractThe friction properties of vapor‐grown carbon nanofibers (VGCFs) reinforced natural rubber (NR) composites were investigated with the ball‐on‐plate sliding test. A mechanism was proposed on the basis of the viscoelastic properties, morphology and hardness of the composites, determined using dynamic mechanical analysis, optical microscopy, field emission scanning electron microscopy, transmission electron microscopy and a hardness‐testing device. The friction behavior of NR/VGCF composites showed three different stages: an increment trend at first stage, a decrement trend at second stage and a stable state at third stage. The peak values of friction coefficient were similar, and the peak shifted to a smaller cycle with increased VGCF content. The eventual friction coefficient decreased with increased VGCF content due to accelerated formation of abrasion patterns in the NR/VGCF composites. Moreover, the arranged VGCFs contributed to the self‐lubrication of NR/VGCF composites and the NR/20 wt% VGCF composite had the smallest friction coefficient. POLYM. COMPOS., 2011.© 2011 Society of Plastics Engineers
Differential proteome analysis of Chikungunya virus‐infected new‐born mice tissues reveal implication of stress, inflammatory and apoptotic pathways in disease pathogenesis
Authors: Dhanwani Rekha , Khan Mohsin , Alam Syed Imtiyaz , Rao Putcha Venkata Lakshmana , Parida Manmohan 
Published: March 2011

AbstractChikungunya infection is a major disease of public health concern. The recurrent outbreaks of this viral disease and its progressive evolution demands a potential strategy to understand major aspects of its pathogenesis. Unlike other alphaviruses, Chikungunya virus (CHIKV) pathogenesis is poorly understood. In every consecutive outbreak, some new symptoms associated with virulence and disease manifestations are being reported such as neurological implication, increased severity and enhanced vector competence. In order to unravel the mechanism of the disease process, proteomic analysis was performed to evaluate the host response in CHIKV‐infected mice tissues. Comparative analysis of the multiple gels representing the particular tissue extract from mock and CHIKV‐infected tissues revealed a drastic reprogramming of physiological conditions through 35 and 15 differentially expressed proteins belonging to different classes such as stress, inflammation, apoptosis, urea cycle, energy metabolism, etc. from liver and brain, respectively. Based on the alterations obtained in the CHIKV mouse model, most of the aspects of CHIKV infection such as disease severity, neurological complications, disease susceptibility and immunocompetence could be defined. This is the first report unravelling the complicated pathways involved in the mechanism of Chikungunya disease pathogenesis employing proteomic approach.
Proteomic analysis of the effects of the immunomodulatory mycotoxin deoxynivalenol
Authors: da Costa André Nogueira , Mijal Renée S. , Keen Jeffrey N. , Findlay John B. C. , Wild Christopher P. 
Published: March 2011

AbstractThe mycotoxin deoxynivalenol (DON) contaminates cereals worldwide and is a common contaminant in the Western European diet. At high doses, DON induces acute gastrointestinal toxicity; chronic, low‐dose effects in humans are not well described, but immunotoxicity has been reported. In this study, 2‐DE was used to identify proteomic changes in human B (RPMI1788) and T (JurkatE6.1) lymphocyte cell lines after exposure to minimally toxic concentrations (up to 500 ng/mL) for 24 h. Proteins which changed their abundance post treatment, by a greater than 1.4‐fold change reproducible in three separate experiments consisting of 36 gels in total, are ubiquitin carboxyl‐terminal hydrolase isozyme L3, proteasome subunit β type‐4 and α type‐6, inosine‐5′‐monophosphate dehydrogenase 2, GMP synthase, microtubule‐associated protein RP/EB family member 1 (EB1), RNA polymerases I, II, III subunit ABC1, triosephosphate isomerase and transketolase. Flow cytometry was used to validate changes to protein expression, except for EB1. These findings provide insights as to how low‐dose exposure to DON may affect human immune function and may provide mechanism‐based biomarkers for DON exposure.
Proteomics reveals potential biomarkers of seed vigor in sugarbeet
Authors: Catusse Julie , Meinhard Juliane , Job Claudette , Strub Jean‐Marc , Fischer Uwe , Pestsova Elena , Westhoff Peter , Van Dorsselaer Alain , Job Dominique 
Published: March 2011

AbstractTo unravel biomarkers of seed vigor, an important trait conditioning crop yield, a comparative proteomic study was conducted with sugarbeet seed samples of varying vigor as generated by an invigoration treatment called hydropriming and an aging treatment called controlled deterioration. Comparative proteomics revealed proteins exhibiting contrasting behavior between seed samples. Thus, 18 proteins were up‐regulated during priming and down‐regulated during aging and further displayed an up‐regulation upon priming of the aged seeds, meaning that down‐regulation of these spot volumes during aging was reversible upon subsequent priming. Also, 11 proteins exhibited the converse behavior characterized by a decrease and an increase of the spot volumes during priming and aging of the control seeds, respectively, and a decrease in the spot volumes upon priming of the aged seeds. The results underpinned the role in seed vigor of several metabolic pathways involved in lipid and starch mobilization, protein synthesis or the methyl cycle. They also corroborate previous studies suggesting that the glyoxylate enzyme isocitrate lyase, the capacity of protein synthesis and components of abscisic acid signaling pathways are likely contributors of seed vigor.
Proteomes of the barley aleurone layer: A model system for plant signalling and protein secretion
Authors: Finnie Christine , Andersen Birgit , Shahpiri Azar , Svensson Birte 
Published: March 2011

AbstractThe cereal aleurone layer is of major importance due to its nutritional properties as well as its central role in seed germination and industrial malting. Cereal seed germination involves mobilisation of storage reserves in the starchy endosperm to support seedling growth. In response to gibberellic acid produced by the embryo, the aleurone layer synthesises hydrolases that are secreted to the endosperm for the degradation of storage products. The barley aleurone layer can be separated from the other seed tissues and maintained in culture, allowing the study of the effect of added signalling molecules in an isolated system. These properties have led to its use as a model system for the study of plant signalling and germination. More recently, proteome analysis of the aleurone layer has provided new insight into this unique tissue including identification of plasma membrane proteins and targeted analysis of germination‐related changes and the thioredoxin system. Here, analysis of intracellular and secreted proteomes reveals features of the aleurone layer system that makes it promising for investigations of plant protein secretion mechanisms.