bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of tissue edema in patients with acute myocardial infarction by computer‐assisted quantification of triple inversion recovery prepared MRI of the myocardium
Authors: Johnstone R. I. , Greenwood J. P. , Biglands J. D. , Plein S. , Ridgway J. P. , Radjenovic A. 
Published: March 2011

AbstractThe aim of this study was to design a computer algorithm to assess the extent of cardiac edema from triple inversion recovery MR images of the human left ventricular myocardium. Twenty‐one patients presenting with acute myocardial infarction were scanned within 48 h of the onset of symptoms. Eight patients were scanned a second time, 4 weeks after the initial event. Myocardial edema was detected in 27 of 29 studies using visual contour‐based manual segmentation. A reference standard, created from the segmentations of three raters by voxel‐wise majority voting, was compared to the edema mass estimates obtained using a newly developed computer algorithm. At baseline (n = 20), the reference standard yielded an edema mass of 16.4 ± 15.0 g (mean ± SD) and the computer algorithm edema mass was 16.4 ± 12.6 g. At follow‐up (n = 7), the reference standard edema mass was 7.1 ± 4.4 g compared to 16.3 ± 7.7 g at baseline. Computer algorithm estimates showed the same pattern of change with 5.7 ± 5.7 g at follow‐up compared to 20.8 ± 13.8 g at baseline. Although there was a significant degree of discrepancy between reference standard and computer algorithm estimates of edema mass in individual patients, their overall agreement was good, with intraclass correlation coefficient ICC(3, 1) = 0.753. Magn Reson Med, 2010. © 2011 Wiley‐Liss, Inc.
Extended graphical model for analysis of dynamic contrast‐enhanced MRI
Authors: Chen Huijun , Li Feiyu , Zhao Xihai , Yuan Chun , Rutt Brian , Kerwin William S. 
Published: March 2011

AbstractKinetic analysis with mathematical models has become increasingly important to quantify physiological parameters in computed tomography (CT), positron emission tomography (PET), and dynamic contrast‐enhanced MRI (DCE‐MRI). The modified Kety/Tofts model and the graphical (Patlak) model have been widely applied to DCE‐MRI results in disease processes such as cancer, inflammation, and ischemia. In this article, an intermediate model between the modified Kety/Tofts and Patlak models is derived from a mathematical expansion of the modified Kety/Tofts model. Simulations and an in vivo experiment involving DCE‐MRI of carotid atherosclerosis were used to compare the new extended graphical model with the modified Kety/Tofts model and the Patlak model. In our simulated circumstances and the carotid artery application, we found that the extended graphical model exhibited lower noise sensitivity and provided more accurate estimates of the volume transfer constant (Ktrans) and fractional plasma volume (vp) than the modified Kety/Tofts model for DCE‐MRI acquisitions of total duration less than 100–300 s, depending on kinetic parameters. In comparison with the Patlak model, we found that the extended graphical model exhibited 74.4–99.8% less bias in estimates of Ktrans. Thus, the extended graphical model may allow kinetic modeling of DCE‐MRI results with shortened data acquisition periods, without sacrificing accuracy in estimates of Ktrans and vp. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Spatially dependent filtering for removing phase distortions at the cortical surface
Authors: Ng Amanda , Johnston Leigh , Chen Zhaolin , Cho Zang‐Hee , Zhang Jingxin , Egan Gary 
Published: March 2011

AbstractRecent advances in high field magnetic resonance technology have increased the interest in the phase of the complex data. Processed phase images are derived from the phase signal by removing the bias field and phase wraps from the initial data. However, the usefulness of this data has been hindered by artifacts at the brain/non‐brain surface, particularly in cortical regions. A method is proposed that efficiently removes surface artifacts by performing Gaussian filtering with spatially varying parameters of unwrapped or complex filtered phase images. The proposed method is shown to produce improved images, revealing underlying structure and detail that are otherwise obscured by surface artifacts in images produced by traditional phase processing methods. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Multipathway sequences for MR thermometry
Authors: Madore Bruno , Panych Lawrence P. , Mei Chang‐Sheng , Yuan Jing , Chu Renxin 
Published: March 2011

AbstractMR‐based thermometry is a valuable adjunct to thermal ablation therapies as it helps to determine when lethal doses are reached at the target and whether surrounding tissues are safe from damage. When the targeted lesion is mobile, MR data can further be used for motion‐tracking purposes. The present work introduces pulse sequence modifications that enable significant improvements in terms of both temperature‐to‐noise‐ratio properties and target‐tracking abilities. Instead of sampling a single magnetization pathway as in typical MR thermometry sequences, the pulse‐sequence design introduced here involves sampling at least one additional pathway. Image reconstruction changes associated with the proposed sampling scheme are also described. The method was implemented on two commonly used MR thermometry sequences: the gradient‐echo and the interleaved echo‐planar imaging sequences. Data from the extra pathway enabled temperature‐to‐noise‐ratio improvements by up to 35%, without increasing scan time. Potentially of greater significance is that the sampled pathways featured very different contrast for blood vessels, facilitating their detection and use as internal landmarks for tracking purposes. Through improved temperature‐to‐noise‐ratio and lesion‐tracking abilities, the proposed pulse‐sequence design may facilitate the use of MR‐monitored thermal ablations as an effective treatment option even in mobile organs such as the liver and kidneys. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Increasing spoiling efficiency in RF‐spoiled gradient echo sequences by averaging of RF phase‐cycle‐adaptedk‐spaces
Authors: Leupold Jochen , Hennig Jürgen 
Published: March 2011

AbstractA method is presented that improves the effectiveness of RF‐spoiling whenever an image consists of the averaging of several identical single acquisitions. Using this method, it becomes possible to reduce the necessary moment of the spoiler gradient by a factor equal to the number of averages. The idea is to perform the collection ofk‐space lines such that the averaging takes over a part of the spoiling process. The number of sequence cycles played out between two acquisitions of a certaink‐space line is adjusted based on both the number of total averages of this line and the phase‐cycling pattern of the RF‐pulse train of a RF‐spoiled gradient echo sequence. In this way, ghost artifacts visible in the single images add to zero in the averaged image while the depiction of the object experiences normal averaging with enhanced signal‐to‐noise ratio. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Structure and function of the skeletal muscle extracellular matrix
Authors: Gillies Allison R. , Lieber Richard L. 
Published: March 2011

AbstractThe skeletal muscle extracellular matrix (ECM) plays an important role in muscle fiber force transmission, maintenance, and repair. In both injured and diseased states, ECM adapts dramatically, a property that has clinical manifestations and alters muscle function. Here we review the structure, composition, and mechanical properties of skeletal muscle ECM; describe the cells that contribute to the maintenance of the ECM; and, finally, overview changes that occur with pathology. New scanning electron micrographs of ECM structure are also presented with hypotheses about ECM structure–function relationships. Detailed structure–function relationships of the ECM have yet to be defined and, as a result, we propose areas for future study. Muscle Nerve 44: 318–331, 2011
Looking for differences in copy number between blood and brain in sporadic amyotrophic lateral sclerosis
Authors: Pamphlett Roger , Morahan Julia M. , Luquin Natasha , Yu Bing 
Published: March 2011

AbstractIntroduction: Most analyses of blood DNA in sporadic neuromuscular disorders have been inconclusive. This may be because some genetic variants occur only in brain tissue. We therefore looked for copy number variants (CNVs) in both blood and brain in patients with sporadic amyotrophic lateral sclerosis (SALS). Methods:
Genome‐wide CNVs were compared in blood and brain from 32 SALS patients and from 26 normal (control) brains, using Affymetrix 6.0 arrays. Results: There were 410 CNVs present in brain but not blood (somatic CNVs) in 94% of the patients (median 8 CNVs per patient). Twenty‐four of the somatic CNVs were rare, were not found in control brains, and overlapped with genes. Conclusions: Brain‐specific CNVs may be common and appear to be present in a proportion of patients with SALS. The more detailed copy number analysis that is becoming available with massively parallel sequencing may uncover brain‐specific CNVs that underlie some cases of SALS. Muscle Nerve, 2011
Transmit gain calibration for nonproton MR using the Bloch–Siegert shift
Authors: Schulte Rolf F. , Sacolick Laura , Deppe Martin H. , Janich Martin A. , Schwaiger Markus , Wild Jim M. , Wiesinger Florian 
Published: March 2011

AbstractTransmit gain (B) calibration is necessary for the adjustment of radiofrequency (RF) power levels to the desired flip angles. In proton MRI, this is generally an automated process before the actual scan without any user interaction. For other nuclei, it is usually time consuming and difficult, especially in the case of hyperpolarised MR. In the current work, transmit gain calibration was implemented on the basis of the Bloch–Siegert phase shift. From the same data, the centre frequency, line broadening and SNR could also be determined. The T1 and B0 insensitivity, and the wide range of B over which this technique is effective, make it well suited for nonproton applications. Examples are shown for hyperpolarised 13C and 3He applications. Copyright © 2011 John Wiley & Sons, Ltd.
A novel background field removal method for MRI using projection onto dipole fields (PDF)
Authors: Liu Tian , Khalidov Ildar , de Rochefort Ludovic , Spincemaille Pascal , Liu Jing , Tsiouris A. John , Wang Yi 
Published: March 2011

AbstractFor optimal image quality in susceptibility‐weighted imaging and accurate quantification of susceptibility, it is necessary to isolate the local field generated by local magnetic sources (such as iron) from the background field that arises from imperfect shimming and variations in magnetic susceptibility of surrounding tissues (including air). Previous background removal techniques have limited effectiveness depending on the accuracy of model assumptions or information input. In this article, we report an observation that the magnetic field for a dipole outside a given region of interest (ROI) is approximately orthogonal to the magnetic field of a dipole inside the ROI. Accordingly, we propose a nonparametric background field removal technique based on projection onto dipole fields (PDF). In this PDF technique, the background field inside an ROI is decomposed into a field originating from dipoles outside the ROI using the projection theorem in Hilbert space. This novel PDF background removal technique was validated on a numerical simulation and a phantom experiment and was applied in human brain imaging, demonstrating substantial improvement in background field removal compared with the commonly used high‐pass filtering method. Copyright © 2011 John Wiley & Sons, Ltd.
Detection accuracy of network anomalies using sampled flow statistics
Authors: Kawahara Ryoichi , Ishibashi Keisuke , Mori Tatsuya , Kamiyama Noriaki , Harada Shigeaki , Hasegawa Haruhisa , Asano Shoichiro 
Published: March 2011

SUMMARYWe investigated the detection accuracy of network anomalies when using flow statistics obtained through packet sampling. Through a case study based on measurement data, we showed that network anomalies generating a large number of small flows, such as network scans or SYN flooding, become difficult to detect during packet sampling. We then developed an analytical model that enables us to quantitatively evaluate the effect of packet sampling and traffic conditions, such as anomalous traffic volume, on detection accuracy. We also investigated how the detection accuracy worsens when the packet sampling rate decreases. In addition, we show that, even with a low sampling rate, spatially partitioning monitored traffic into groups makes it possible to increase detection accuracy. We also developed a method of determining an appropriate number of partitioned groups, and we show its effectiveness. Copyright © 2011 John Wiley & Sons, Ltd.
A Bessel collocation method for numerical solution of generalized pantograph equations
Authors: Yüzbaşi Şuayip , Şahin Niyazi , Sezer Mehmet 
Published: March 2011

AbstractThis article is concerned with a generalization of a functional differential equation known as the pantograph equation which contains a linear functional argument. In this article, we introduce a collocation method based on the Bessel polynomials for the approximate solution of the pantograph equations. The method is illustrated by studying the initial value problems. The results obtained are compared by the known results. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011
A relaxation method of an alternating iterative MFS algorithm for the Cauchy problem associated with the two‐dimensional modified Helmholtz equation
Authors: Marin Liviu 
Published: March 2011

AbstractWe propose two algorithms involving the relaxation of either the given Dirichlet data or the prescribed Neumann data on the over‐specified boundary in the case of the alternating iterative algorithm of Kozlov et al. (USSR Comput Math Math Phys 31 (1991), 45–52) applied to the Cauchy problem for the two‐dimensional modified Helmholtz equation. The two mixed, well‐posed and direct problems corresponding to every iteration of the numerical procedure are solved using the method of fundamental solutions (MFS), in conjunction with the Tikhonov regularization method. For each direct problem considered, the optimal value of the regularization parameter is selected according to the generalized cross‐validation criterion. The iterative MFS algorithms with relaxation are tested for Cauchy problems associated with the modified Helmholtz equation in two‐dimensional geometries to confirm the numerical convergence, stability, accuracy and computational efficiency of the method. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011
The benefits and costs of the Section 8 housing subsidy program: A framework and estimates of first‐year effects
Authors: Carlson Deven , Haveman Robert , Kaplan Thomas , Wolfe Barbara 
Published: March 2011

AbstractThis paper provides estimates for a comprehensive set of social benefits and costs associated with the federal Housing Choice Voucher ( Section 8) program. The impact categories for which we provide empirical estimates include the value of the voucher to recipients; additional services and public benefits induced by voucher receipt; improvements in children's health, education, and criminal behaviors; the costs of voucher provision; the labor supply impacts on voucher recipients; and community effects. These estimates rest largely on empirical analyses of the effect of voucher receipt on several recipient and taxpayer behaviors and outcomes that occur in the first year of voucher receipt. The analysis distinguishes benefits and costs accruing to program participants, nonparticipants—including taxpayers and property owners—and society as a whole. Our analysis suggests that the program is likely to meet the efficiency standard of positive net social benefits. © 2011 by the Association for Public Policy Analysis and Management.
Swelling of glass‐fiber reinforced polyamide 66 during conditioning in water, ethylene glycol, and antifreeze mixture
Authors: Thomason James L. , Porteus Glen 
Published: March 2011

AbstractThe weight and dimensional changes of injection‐molded glass‐fiber reinforced polyamide 66 composites based on two glass fiber products with different sizing formulations and unreinforced polymer samples have been characterized during conditioning in water, ethylene glycol, and a water‐glycol mixture at 50°C and 70°C for a range of times up to 900 h. The results reveal that hydrothermal ageing in these fluids causes significant changes in the weight and dimensions of these materials. All conditioned materials showed a time dependent weight and dimension increase. The change observed in water could be well modeled by a simple Fickian diffusion process; however, the absorption process followed a more complex pattern in the other conditioning fluids. It was not apparent that changing the glass fiber sizing affected the dimensional stability of the composites under these relatively mild conditions. There was a strong correlation between the swelling of these samples and the level of fluid absorption. The composites exhibited highly aniosotropic levels of swelling. These effects were well in line with the influence of fibers on restriction of the matrix deformation in the fiber direction. The polymer and composite swelling coefficients correlated well with data previously obtained at higher conditioning temperatures. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Synthesis and swelling properties of protein‐poly(acrylic acid‐co‐acrylamide) superabsorbent composite
Authors: Zhang Buning , Cui Yingde , Yin Guoqiang , Li Xinming , Liao Liewen , Cai Xibin 
Published: March 2011

AbstractA novel superabsorbent polymer composite was synthesized by graft copolymerization of cottonseed protein and acrylic monomers in order to explore the new application of cottonseed protein in nonfood field. This composite was synthesized by solution based copolymerization, using partly neutralized acrylic acid, acrylamide and cottonseed protein as raw material, N,N‐methylene bisacrylamide as crosslinking agent, potassium persulphate and sodium sulfite as the initiators. The effects of the certain variables of the copolymerization on the water absorbency of the synthesized composite were measured. The chemical structure of the composite was characterized by means of Fourier transform infrared spectroscopy, differential scanning calorimetry and thermogravimetry analysis. The swelling properties of the composite were carried out under varying pH conditions. Further, the saline sensitivity, swelling kinetics and water retention ability of the composite was investigated. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Assessment of the relevance of sintering in thermoplastic commingled yarn consolidation
Authors: Greco Antonio , Strafella Alessandra , Tegola Carola La , Maffezzoli Alfonso 
Published: March 2011

AbstractThe aim of the present article is to study the different phenomena which are at the basis of the consolidation of commingled thermoplastic semi‐pregs made of amorphous polyester fibers and E‐glass reinforcement. The evolution of the void fraction during the consolidation of the composite was monitored by a dynamometer, equipped with parallel plates and a forced convection oven. Different physical changes were associated to the consolidation temperature. Scanning electron microscopy (SEM) and thermomecahnical analysis (TMA) showed that at low temperature, matrix fiber deformation and sintering are responsible of the initial void reduction. At a temperature higher than the onset of the flow region, reinforcement impregnation is responsible of the further void reduction. Dimensionless analysis confirmed that at lower temperatures, corresponding to higher viscosities, consolidation due to viscous flow of the polymer matrix is negligible compared to consolidation due to sintering of matrix fibers. The results indicate that the Darcy law can efficiently represent the consolidation during the microscale impregnation of the reinforcement, but cannot account for the initial stages of consolidation. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Staphylococcus aureus physiological growth limitations: Insights from flux calculations built on proteomics and external metabolite data
Authors: Liang Chunguang , Liebeke Manuel , Schwarz Roland , Zühlke Daniela , Fuchs Stephan , Menschner Leonhard , Engelmann Susanne , Wolz Christiane , Jaglitz Sarah , Bernhardt Jörg , Hecker Michael , Lalk Michael , Dandekar Thomas 
Published: March 2011

AbstractComparing proteomics and metabolomics allows insights into Staphylococcus aureus physiological growth. We update genome and proteome information and deliver strain‐specific metabolic models for three S. aureus strains (COL, N315, and Newman). We find a number of differences in metabolism and enzymes. Growth experiments (glucose or combined with oxygen limitation) were conducted to measure external metabolites. Fluxes of the central metabolism were calculated from these data with low error. In exponential phase, glycolysis is active and amino acids are used for growth. In later phases, dehydroquinate synthetase is suppressed and acetate metabolism starts. There are strain‐specific differences for these phases. A time series of 2‐D gel protein expression data on COL strain delivered a second data set (glucose limitation) on which fluxes were calculated. The comparison with the metabolite‐predicted fluxes shows, in general, good correlation. Outliers point to different regulated enzymes for S. aureus COL under these limitations. In exponential growth, there is lower activity for some enzymes in upper glycolysis and pentose phosphate pathway and stronger activity for some in lower glycolysis. In transition phase, aspartate kinase is expressed to meet amino acid requirements and in later phases there is high expression of glyceraldehyde‐3‐phosphate dehydrogenase and lysine synthetase. Central metabolite fluxes and protein expression of their enzymes correlate in S. aureus.
Reboot the system thanks to protein post‐translational modifications and proteome diversity: How quiescent seeds restart their metabolism to prepare seedling establishment
Authors: Arc Erwann , Galland Marc , Cueff Gwendal , Godin Béatrice , Lounifi Imen , Job Dominique , Rajjou Loïc 
Published: March 2011

AbstractOnce liberated in their environment, orthodox seeds live in a quiescent dehydrated state not totally exempt of essential molecular events as, for example, the capacity of breaking dormancy during after‐ripening. Upon imbibition, if internal regulatory padlocks are released and given adequate external conditions, the quiescent seed is able to “reboot” its system and, thus, germinate. Recent studies unraveled the crucial importance of protein PTMs in seed dormancy, longevity and vigor. As compared to other plant developmental stages, the seed proteome appears quite unique and diverse. Seed proteins encompass several functional classes from primary and secondary metabolism to structural and antimicrobial defense. In the dry state, oxidative damages can occur due to reactive oxygen and nitrogen species produced by non‐enzymatic reactions. These reactive species can affect proteins by the oxidation of their amino acids in a post‐translational manner. The hormone abscisic acid regulates major aspects of seed life including dormancy and germination. This signaling pathway has been shown to rely on several PTMs such as protein phosphorylation or ubiquitination.