bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deep venous thrombosis: Diagnostic value of non‐contrast‐enhanced MR venography using electrocardiography‐triggered three‐dimensional half‐fourier FSE
Authors: Ono Atsushi , Murase Kenya , Taniguchi Toshitaka , Shibutani Osamu , Takata Satoru , Kobashi Yasuyuki , Hashiguchi Yusuke , Miyazaki Mitsue 
Published: May 2010

AbstractWe prospectively assessed the diagnostic accuracy of non‐contrast‐enhanced MR venography using both the flow‐refocused fresh‐blood imaging (FR‐FBI) and the swap phase‐encode arterial double‐subtraction elimination (SPADE) techniques for detecting deep vein thrombosis (DVT), as compared using conventional X‐ray venography as the reference standard. Forty‐one legs of 32 consecutive patients (eight men, 24 women; mean age ± standard deviation, 69.4 ± 15.3 years) suspected of having deep vein thrombosis and thus examined using conventional X‐ray venography underwent MR FR‐FBI and SPADE. Twenty‐five of the 32 patients had nonmagnetizing, metal implants they had received during hip or leg surgery. Two radiologists independently assessed the MR venograms as either diagnostic or nondiagnostic and with either the presence or absence of thrombi. The sensitivities of FR‐FBI and SPADE for diagnosing thrombus were 100% (53 of 53) for both reviewers. Nondiagnostic segments were excluded from this analysis. The corresponding specificities were 100% (238 of 238 for reviewer A) and 99.6% (237 of 238 for reviewer B). The interobserver agreement regarding the MR images for the assessment of thrombosis was high (κ = 0.92). Non‐contrast‐enhanced MR venography using SPADE and FR‐FBI is highly accurate and reproducible for diagnosing DVT. This is especially advantageous for patients who have received nonmagnetizing, metal implants during orthopedic surgery. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Measurement of perfusion and permeability from dynamic contrast‐enhanced MRI in normal and pathological vertebral bone marrow
Authors: Biffar Andreas , Sourbron Steven , Schmidt Gerwin , Ingrisch Michael , Dietrich Olaf , Reiser Maximilian F. , Baur‐Melnyk Andrea 
Published: May 2010

AbstractDynamic contrast‐enhanced MRI data in vertebral bone marrow (vBM) are currently analyzed with descriptive indices. The purpose of this study was to develop and evaluate a quantitative approach, considering the tissue composition of vBM. Therefore, a measurement of the water fraction, fwat, and the precontrast relaxation times, T10 wat, T10 fat, was added to the routine protocol. Signal analysis was generalized by allowing for an arbitrary fraction of fat. Plasma flow, plasma volume, extraction flow, and interstitial volume were determined from dynamic contrast‐enhanced‐MRI data. Simulations were used to determine the sensitivity to the precontrast values and to retrospectively verify the choice of the sequence parameters. Measurements were performed in healthy vertebral bodies (n = 30) and lesions of 15 patients with vertebral fractures. Extraction flow (milliliters per 100 mL/min) provided the strongest normal/abnormal separation: mean (standard deviation) was 0.3 (0.8) in healthy vBM and 6(4) in the fractures. Neglecting the fat component and the approximated signal analysis using relative signal enhancement produced significant differences. We conclude that correcting for the fat component in the signal and parametrization by tracer‐kinetic analysis is necessary to avoid misinterpretation and/or systematic errors. The quantitative analysis is equally well suited as a descriptive parameter for the differentiation between normal and abnormal vertebral bone marrow. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
O‐space imaging: Highly efficient parallel imaging using second‐order nonlinear fields as encoding gradients with no phase encoding
Authors: Stockmann Jason P. , Ciris Pelin Aksit , Galiana Gigi , Tam Leo , Constable R. Todd 
Published: May 2010

AbstractRecent improvements in parallel imaging have been driven by the use of greater numbers of independent surface coils placed so as to minimize aliasing along the phase‐encode direction(s). However, gains from increasing the number of coils diminish as coil coupling problems begin to dominate and the ratio of acceleration gain to expense for multiple receiver chains becomes prohibitive. In this work, we redesign the spatial‐encoding strategy in order to gain efficiency, achieving a gradient encoding scheme that is complementary to the spatial encoding provided by the receiver coils. This approach leads to “O‐space” imaging, wherein the gradient shapes are tailored to an existing surface coil array, making more efficient use of the spatial information contained in the coil profiles. In its simplest form, for each acquired echo the Z2 spherical harmonic is used to project the object onto sets of concentric rings, while the X and Y gradients are used to offset this projection within the imaging plane. The theory is presented, an algorithm is introduced for image reconstruction, and simulations reveal that O‐space encoding achieves high encoding efficiency compared to sensitivity encoding (SENSE) radial k‐space trajectories, and parallel imaging technique with localized gradients (PatLoc), suggesting that O‐space imaging holds great potential for accelerated scanning. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Prospective motion correction for single‐voxel 1H MR spectroscopy
Authors: Keating Brian , Deng Weiran , Roddey J. Cooper , White Nathan , Dale Anders , Stenger V. Andrew , Ernst Thomas 
Published: May 2010

AbstractHead motion during 1H MR spectroscopy acquisitions may compromise the quality and reliability of in vivo metabolite measurements. Therefore, a three‐plane image‐based motion‐tracking module was integrated into a single‐voxel 1H MR spectroscopy (point‐resolved spectroscopy) sequence. A series of three orthogonal spiral navigator images was acquired immediately prior to the MR spectroscopy water suppression module in order to estimate head motion. By applying the appropriate rotations and translations, the MR spectroscopy voxel position can be updated such that it remains stationary with respect to the brain. Frequency and phase corrections were applied during postprocessing to reduce line width and restore coherent averaging. Spectra acquired during intentional head motion in 11 volunteers demonstrate reduced lipid contamination and increased spectral reproducibility when motion correction is applied. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Analytical solutions for advective–dispersive solute transport in double‐layered finite porous media
Authors: Li Yu‐Chao , Cleall Peter John 
Published: May 2010

AbstractAnalytical solutions for advection and dispersion of a conservative solute in a one‐dimensional double‐layered finite porous media are presented. The solutions are applicable to five scenarios that have various combinations of fixed concentration, fixed flux and zero concentration gradient conditions at the inlet and outlet boundaries that provide a wide number of options. Arbitrary initial solute concentration distributions throughout the media can be considered via explicit formulations or numerical integration. The analytical solutions presented have been verified against numerical solutions from a finite‐element‐based approach and an existing closed‐form solution for double‐layered media with an excellent correlation being found in both cases. A practical application pertaining to advective transport induced by consolidation of underlying sediment layers on contaminant movement within a capped contaminated sediment system is presented. Comparison of the calculated concentrations and fluxes with alternative approaches clearly illustrates the need to consider advection processes. Consideration of the different features of contaminant transport due to varying pore‐water velocity fields in primary consolidation and secondary consolidation stages is achieved via the use of non‐uniform initial concentration distributions within the proposed analytical solutions. Copyright © 2010 John Wiley & Sons, Ltd.
Anisotropic model of damage for geomaterials and concrete
Authors: Alliche Abdenour , Dumontet Helene 
Published: May 2010

AbstractA damage model for geomaterials and concrete is proposed. This model expresses the anisotropic character induced by the degradation of material. The law of behavior obtained by differentiation of the free energy shows the dissymmetry effect observed in traction–compression loading and the residual strains caused by the damage.The present approach requires the identification of a reduced number of parameters having a clear physical significance. An application to the case of the uniaxial traction–compression loading shows a good adequacy with the experimental observations. Copyright © 2010 John Wiley & Sons, Ltd.
A macroelement formulation for shallow foundations on cohesive and frictional soils
Authors: Chatzigogos C. T. , Figini R. , Pecker A. , Salençon J. 
Published: May 2010

AbstractThe scope of this paper is to present a macroelement model for shallow foundations encompassing the majority of combinations of soil and foundation–soil interface conditions that are interesting for practical applications. The basic idea of the formulation is to raise the common assumption that the surface of ultimate loads of the foundation is identified as a yield surface in the space of force parameters which the footing is subjected to. Instead, each non‐linear mechanism participating in the global response of the system is modelled independently and the surface of ultimate loads is retrieved as the combined result of all active mechanisms. This allows formulating each mechanism by respecting its particular characteristics and offers the possibility of activating, modifying or deactivating each mechanism according to the context of application. The model comprises three non‐linear mechanisms: (a) the mechanism of sliding at the soil–footing interface, (b) the mechanism of soil yielding in the vicinity of the footing and (c) the mechanism of uplift as the footing may get detached from the soil. The first two are irreversible and dissipative and are combined within a multi‐mechanism plasticity formulation. The third mechanism is reversible and non‐dissipative. It is reproduced with a phenomenological non‐linear hyperelastic model. The model is validated with respect to the existing results for shallow foundations under quasi‐static loading tests. It is shown that although the ultimate surface of the foundation is not explicitly used in the formulation of the model, the obtained force states by the model are always contained within it. Copyright © 2010 John Wiley & Sons, Ltd.
Developing elasto‐plastic models without establishing any expression for the yield function
Authors: Sands C. M. , Chandler H. W. , Guz I. A. 
Published: May 2010

AbstractThis paper presents a procedure for developing elasto‐plastic material models from a dissipation function and kinematic constraint that obviates the need to establish an expression for the yield function. This method could be applied to a wide range of different materials, but it is particularly suitable for testing new models of granular materials. This is because there is often a difficulty associated with finding an algebraic expression for the yield function for appropriate dissipation functions combined with realistic dilatancy rules. The procedure presented in this paper allows the approach to fulfill its potential for the easy incorporation of physical insight into the dissipation function and kinematic constraint without being hindered by algebraic complexity. The method is applied to the familiar von Mises model and also to a model for granular materials that incorporates a realistic dilatancy rule and extends into three dimensions a model presented in earlier work. Copyright © 2010 John Wiley & Sons, Ltd.
Preconditioners in computational geomechanics: A survey
Authors: Gambolati G. , Ferronato M. , Janna C. 
Published: May 2010

AbstractThe finite element (FE) solution of geomechanical problems in realistic settings raises a few numerical issues depending on the actual process addressed by the analysis. There are two basic problems where the linear solver efficiency may play a crucial role: 1. fully coupled consolidation and 2. faulted uncoupled consolidation. A class of general solvers becoming increasingly popular relies on the Krylov subspace (or Conjugate Gradient‐like) methods, provided that an efficient preconditioner is available. For both problems mentioned above, the possible preconditioners include the diagonal scaling (DS), the Incomplete LU decomposition (ILU), the mixed constraint preconditioning (MCP) and the multilevel incomplete factorization (MIF). The development and the performance of these algorithms have been the topic of several recent works. The present paper aims at providing a survey of the preconditioners available to date in computational geomechanics. In particular, a review and a critical discussion of DS, ILU, MCP and MIF are given along with some comparative numerical results. Copyright © 2010 John Wiley & Sons, Ltd.
Robust reliable control for discrete‐time‐delay systems with stochastic nonlinearities and multiplicative noises
Authors: Liu Yisha , Wang Zidong , Wang Wei 
Published: May 2010

AbstractThis paper is concerned with the reliable control problem against actuator failures for a class of uncertain discrete‐time stochastic nonlinear time‐delay systems. The failures of actuators are quantified by a variable varying in a given interval. The stochastic nonlinearities described by statistical means cover several well‐studied nonlinear functions as special cases. The time‐varying delay is unknown with given lower and upper bounds. The multiplicative stochastic disturbances are in the form of a scalar Gaussian white noise with unit variance. Attention is focused on the analysis and design of a stable controller such that, for all possible actuator failures, stochastic nonlinearities and disturbances, time delays and admissible parameter uncertainties, the closed‐loop system is exponentially mean‐square stable. A linear matrix inequality approach is developed to solve the addressed problem. A numerical example is given to demonstrate the effectiveness of the proposed design approach. Copyright © 2010 John Wiley & Sons, Ltd.
Elevated TGFβ–Smad signalling in experimental Pkd1 models and human patients with polycystic kidney disease
Authors: Hassane Sabrine , Leonhard Wouter N , van der Wal Annemieke , Hawinkels Lukas JAC , Lantinga‐van Leeuwen Irma S , Dijke Peter ten , Breuning Martijn H , Heer Emile de , Peters Dorien JM 
Published: May 2010

AbstractAutosomal dominant polycystic kidney disease (ADPKD) is a common inherited renal disease characterized by many fluid‐filled cysts and interstitial fibrosis in the kidneys, leading to chronic renal failure. During cystogenesis the renal tubules undergo extensive structural alterations that are accompanied by altered cellular signalling, directly and/or indirectly regulated by the PKD1 and PKD2 proteins. Since transforming growth factor (TGF)‐β signalling modulates cell proliferation, differentiation, apoptosis, adhesion and migration of various cell types, we studied the activation of this signalling pathway in Pkd1‐mutant mouse models at different stages of the disease. Therefore, we analysed expression of the TGFβ–Smad signalling pathway and its target genes in different Pkd1 mutant mouse models in various stages of polycystic disease. Nuclear accumulation of P‐Smad2 in cyst lining epithelial cells was not observed in the initiation phase but was observed at mild and more advanced stages of PKD. This coincides with mild fibrosis and increased mRNA levels of TGFβ target genes, such as fibronectin, collagen type I, plasminogen activator inhibitor 1 and matrix metalloproteinase‐2. At this stage many interstitial fibroblasts were found around cysts, which also showed nuclear localization for P‐Smad2. However, bone morphogenetic protein (BMP) signalling, which can antagonize TGFβ signalling, is not affected, since nuclear expression of P‐Smad1/5/8 and expression of the BMP target gene, inhibitor of DNA binding/differential‐1 (ID‐1) is not altered compared to wild‐type controls. Also, human kidneys with progressive ADPKD showed increased nuclear localization of P‐Smad2, while in general expression of P‐Smad1/5/8 was weak. These results exclude TGFβ signalling at the initiation of cystogenesis, but indicate an important role during cyst progression and in fibrogenesis of progressive ADPKD. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Factors associated with the use of corticosteroids in the initial management of idiopathic pulmonary fibrosis
Authors: Munson Jeffrey C. , Kreider Maryl , Chen Zhen , Christie Jason D. , Kimmel Stephen E. 
Published: May 2010

AbstractPurposeIdiopathic pulmonary fibrosis (IPF) has not been shown to respond to corticosteroid therapy; however, many patients receive these drugs at the time of diagnosis. The factors that are associated with the decision to prescribe corticosteroids have not been examined.MethodsWe conducted a retrospective cohort study of 1126 patients with a new diagnosis of IPF using The Health Improvement Network (THIN) database from the United Kingdom. We used generalized estimating equation (GEE) regression models to test the association of patient characteristics, co‐morbid diseases, and disease characteristics with the use of corticosteroids within 30 days of IPF diagnosis.ResultsBivariable analyses demonstrated an association between female sex, the presence of dyspnea, the need for oxygen, past steroid use, and the use of corticosteroids immediately prior to diagnosis with the use of corticosteroids at the time of diagnosis. After adjustment with multivariable GEE regression, only the use of oxygen at the time of diagnosis (OR 1.69, CI 1.14–2.49), the past use of corticosteroids (OR 1.50, CI 1.04–2.15), and use of corticosteroids immediately prior to diagnosis (OR 5.72, CI 3.80–8.60) remained significantly associated with the use of corticosteroids immediately following diagnosis. No association was found between prior diabetes, osteoporosis, glaucoma, hypertension, congestive heart failure, obesity, or peptic ulcer disease and use of corticosteroids at diagnosis.ConclusionsThe decision to prescribe corticosteroids is associated with oxygen use and past corticosteroid use but is not influenced by factors such as age, gender, or common co‐morbid conditions that may pre‐dispose patients to adverse events of therapy. Copyright © 2010 John Wiley & Sons, Ltd.
Drift‐diffusion model for intermediate band solar cells including photofilling effects
Authors: Strandberg Rune , Reenaas Turid Worren 
Published: May 2010

AbstractA novel drift‐diffusion model for intermediate band solar cells (IBSC) is presented. The model differs from previous drift‐diffusion models by allowing the carrier concentrations in all three bands to vary. It is developed for the idealized case where only radiative recombination occurs and where the IB has zero width. The model is used to compare the performance of IBSCs where the IB‐region is doped to get a partially filled IB (prefilled IBSC) to IBSCs where the IB‐region is not doped to partially fill the IB (photofilled IBSC). Numerical results show that a photofilled IBSC can achieve high efficiencies when operated under concentrated light. In fact, for some particular cases, a photofilled cell will perform better than a prefilled cell. The optimal degree of prefilling, i.e. the ratio of the concentration of doping atoms to the total number of IB‐states, is found for a particular example. It is also examined how the carrier concentrations in all three bands, the conduction, the intermediate and the valence bands, vary in prefilled and photofilled IBSCs. Finally, the band diagrams of a prefilled and photofilled IBSC are discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Investigation of bulk and solar cell properties of ingots cast from compensated solar grade silicon
Authors: Modanese Chiara , Di Sabatino Marisa , Søiland Anne‐Karin , Peter Kristian , Arnberg Lars 
Published: May 2010

AbstractIn this work, the effect of the concurrent presence of B and P on bulk and solar cell properties of directionally solidified multicrystalline ingots from commercially compensated solar grade silicon (SoG‐Si) feedstock produced by Elkem Solar was investigated. The initial B and P content prior to the directional solidification experiment was 1260 and 762 ppba, respectively. Two reference ingots have been solidified in a silica crucible from 100% electronic grade silicon (EG‐Si) feedstock, with 332 ppba of boron added. All ingots have been cast under similar process parameters. The resistivity measurements by Four Point Probe (FPP) are in good agreement with the net dopant content, i.e., NA − ND for p‐type material, measured by Glow Discharge Mass Spectrometer (GDMS). Bulk lifetime measurements show a decrease in the values compared to the EG reference. Lifetime distributions show the highest values of 13 and 19 µs at approximately half ingot height, compared to 30 and 44 µs in the reference ingots. This decrease can be due to the concurrent effect of compensation and of other impurities present in the ingot. However, the content of several transition metals measured by GDMS at half ingot height was not significantly higher than that of the reference ingots. Oxygen content as measured by Fourier Transform Infra‐Red (FTIR) spectroscopy shows no significant difference compared to the references. Solar cells made from the compensated ingots and processed under standard process conditions show efficiency values up to 15.5% and fill factor values up to 78%, comparable to conventional multicrystalline silicon cells. Copyright © 2010 John Wiley & Sons, Ltd.
Optimization of anti‐reflection moth‐eye structures for use in crystalline silicon solar cells
Authors: Yamada Noboru , Kim Oanh Ngo , Tokimitsu Toru , Nakai Yusuke , Masuda Hideki 
Published: May 2010

AbstractAn anti‐reflection (AR) moth‐eye structure made of acrylic resin and deposited on a polyethylene terephthalate (PET) substrate was optimized in the wavelength range from 400 to 1170 nm; crystalline silicon (c‐Si) solar cells function efficiently in this wavelength range. The rigorous coupled wave analysis (RCWA) method was used for optical simulation, and the Taguchi method was used for efficient optimization. The simulation results showed that the reflectance of the optimized structure over the above‐mentioned wavelength range was less than 0.87% and that a minimal reflectance of 0.1% was observed at 400 nm. Experimental results showed that the reflectance of a fabricated moth‐eye structure was less than 1.0% in the wavelength range and that a minimal reflectance of 0.55% was observed at 700 nm. A c‐Si solar cell, which was enclosed in a polyvinyl butyral (PVB) layer of uniform thickness, was coated with the fabricated moth‐eye film, and it was observed that the moth‐eye film increased electric generation (EG) up to 15%, depending on the incident angle. Further, a daily increase in EG of up to 8.7% was estimated on a clear summer day in Japan when the moth‐eye film was used. Copyright © 2010 John Wiley & Sons, Ltd.