bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flip‐angle mapping of 31P coils by steady‐state MR spectroscopic imaging
Authors: Chmelík Marek , Považan Michal , Jírů Filip , Kukurová Ivica Just , Dezortová Monika , Krššák Martin , Bogner Wolfgang , Hájek Milan , Trattnig Siegfried , Valkovič Ladislav 
Published: November 2013

PurposePhosphorus (31P) MR spectroscopic imaging (MRSI) is primarily applied with sensitive, surface radiofrequency (RF) coils that provide inhomogeneous excitation RF field (B1+) and rough localization due to their B1+ and sensitivity (B1−) profiles. A careful and time‐consuming pulse adjustment and an accurate knowledge of flip angle (FA) are mandatory for quantification corrections.Materials and MethodsIn this study, a simple, fast, and universal 31P B1+ mapping method is proposed, which requires fast steady‐state MRSI (typically one sixth of normal measurement time) in addition to the typical MRSI acquired within the examination protocol. The FA maps are calculated from the ratio of the signal intensities acquired by these two measurements and were used to correct for the influence of B1+ on the metabolite maps.ResultsIn vitro tests were performed on two scanners (3 and 7 Tesla) using a surface and a volume coil. The calculated FA maps were in good agreement with adjusted nominal FAs and the theoretical calculation using the Biot‐Savart law. The method was successfully tested in vivo in the calf muscle and the brain of healthy volunteers (n = 4). The corrected metabolite maps show higher homogeneity compared with their noncorrected versions.ConclusionThe calculated FA maps helped with B1+ inhomogeneity corrections of acquired in vivo data, and should also be useful with optimization and testing of pulse performances, or with the construction quality tests of new dual‐channel 1H/31P coils. J. Magn. Reson. Imaging 2014;40:391–397. © 2013 Wiley Periodicals, Inc.
Arterial spin labeling to determine tumor viability in head and neck cancer before and after treatment
Authors: Fujima Noriyuki , Kudo Kohsuke , Yoshida Daisuke , Homma Akihiro , Sakashita Tomohiro , Tsukahara Akiko , Tha Khin Khin , Zaitsu Yuri , Terae Satoshi , Shirato Hiroki 
Published: November 2013

PurposeTo evaluate the feasibility of arterial spin‐labeling (ASL) in head and neck cancer for noninvasive measurement of tumor blood flow (TBF), by comparing 1) the TBF change before and after the treatment, and 2) posttreatment TBF and its reduction rate between residual and nonresidual tumors after treatment.Materials and MethodsTwenty‐two patients with head and neck cancer were evaluated using ASL on 3.0‐T magnetic resonance imaging (MRI) before and after nonsurgical treatment. A pulsed ASL sequence with Look–Locker readout was used to calculate quantitative TBF. TBF reduction rates between pre‐ and posttreatment values were also calculated. Residual tumors were confirmed when present with either histopathologically or clinical follow‐up.ResultsPre‐ and posttreatment mean TBF values were 121.4 ± 27.8 (standard deviation) and 24.9 ± 14.9 mL/100g/min, respectively. Pre‐ and posttreatment TBF differed significantly. Posttreatment TBF was significantly higher in patients with residual tumors (five patients, 46.9 ± 7.1 mL/100g/min) than in those without (17 patients, 18.4 ± 9.2 mL/100g/min). The TBF reduction rate was significantly lower in patients with residual tumors (0.540.55 ± 0.120.12) than in those without (0.85 ± 0.06).ConclusionASL allows quantitative assessment of TBF in head and neck cancer. ASL may be useful for noninvasive assessment of tumor viability in head and neck cancer. J. Magn. Reson. Imaging 2014;40:920–928. © 2013 Wiley Periodicals, Inc.
Postsurgical hemodynamics of the aortic valve bypass operation evaluated with phase contrast magnetic resonance
Authors: Lam Adrian , Clement‐Guinaudeau Stephanie , Padala Muralidhar , Eisner Robert L. , Thourani Vinod , Vadnais David , Hurst Stuart , Guyton Robert A. , Oshinksi John N. 
Published: November 2013

PurposeTo characterize the postsurgical hemodynamics in aortic valve bypass (AVB) patients, and to determine the relationship between presurgical native aortic valve pressure gradient and postsurgical hemodynamics.Materials and MethodsTwenty patients scheduled for AVB surgery underwent presurgical transthoracic Doppler echocardiography to assess the degree of aortic stenosis and postsurgical cardiac magnetic resonance imaging (MRI) to acquire phase contrast magnetic resonance (PCMR) flow values along the ascending and descending aorta, and in the conduit. Net flow values were calculated from the PCMR images and compared to presurgical aortic valve pressure gradient measurements.ResultsPCMR showed that: 1) The blood flow split between the aorta and the conduit was 35%:65% of cardiac output and 2) 60% of patients had net retrograde blood flow in the superior thoracic aorta over the cardiac cycle. Patients with presurgical pressure gradient (ΔP) > 45 mmHg had significantly less blood flow out of the native aorta than patients with ΔP < 45 mmHg, and had significantly more retrograde flow in the superior thoracic aorta postsurgery.ConclusionIn patients undergoing AVB, presurgical aortic valve pressure gradient is associated with the volume of blood flow out the aorta and the direction of blood flow in the superior thoracic aorta after conduit addition as measured by PCMR. J. Magn. Reson. Imaging 2014;40:899–905. © 2013 Wiley Periodicals, Inc.
Investigation of brain hemodynamic changes induced by active and passive movements: A combined arterial spin labeling–BOLD fMRI study
Authors: Boscolo Galazzo Ilaria , Storti Silvia F. , Formaggio Emanuela , Pizzini Francesca B. , Fiaschi Antonio , Beltramello Alberto , Bertoldo Alessandra , Manganotti Paolo 
Published: November 2013

PurposeTo assess the applicability of arterial spin labeling (ASL) in comparison to blood‐oxygenation‐level‐dependent (BOLD) contrast fMRI in detecting brain activations elicited by active and passive hand movements.Materials and MethodsA block design for ASL and BOLD fMRI was applied in 8 healthy subjects using active and passive hand tasks. Data analyses were performed at individual and group level, comparing both the different movements and the performance of the two techniques.ResultsGroup analyses showed involvement of the same areas during both tasks, as the contralateral sensorimotor cortex, supplementary motor area, cerebellum, inferior parietal lobes, thalamus. ASL detected smaller activation volumes than BOLD, but the areas had a high degree of colocalization. Few significant differences (P < 0.05) were found when the two tasks were compared for the number of activated voxels, coordinates of center of mass, and CBF estimates. Considering together all the areas, the mean %BOLD change was 0.79 ± 0.27 and 0.73 ± 0.24 for the active and passive movements respectively, while the mean %CBF changes were 34.1 ± 8.9 and 27.1 ± 14.8.ConclusionOur findings confirm passive and active tasks are strongly coupled, supporting the importance of passive tasks as a diagnostic tool in the clinical setting. ASL fMRI proved suitable for functional mapping and quantifying CBF changes, making it a promising technique for patient cohort applications. J. Magn. Reson. Imaging 2014;40:937–948. © 2013 Wiley Periodicals, Inc.
Quality of 186 child brain spectra using motion and B0 shim navigated single voxel spectroscopy
Authors: Hess Aaron T. , van der Kouwe André J.W. , Mbugua Kenneth K. , Laughton Barbara , Meintjes Ernesta M. 
Published: November 2013

PurposeTo evaluate B0 shim and motion navigated single voxel spectroscopy in children. Assess the repeatability of metabolite concentrations in three regions: medial frontal grey matter, peritrigonal white matter, and basal ganglia. Determine the extent of intra‐ and interacquisition movement in this population.MethodsLinewidth and signal to noise ratio were calculated to assess spectral quality of 186 spectra at 3 Tesla. Repeatability was assessed on 31 repeat scans. Navigator images were used to assess localization errors, while navigator motion and shim logs were used to demonstrate the efficacy of correction needed during the scans.ResultsAverage linewidths ± standard deviations of N‐acetyl aspartate are 3.8 ± 0.6 Hz, 4.4 ± 0.5 Hz, and 4.7 ± 0.8 Hz in each region, respectively. Scan‐to‐scan measurement variance in metabolite concentrations closely resembled the expected variance. A total of 73% and 32% of children moved before and during the acquisition, causing a voxel shift of more than 10% of the voxel volume, 1.5 mm. The predominant movement directions were sliding out of the coil and nodding (up–down rotation). First‐order B0 corrections were significant (>10 μT/m) in 18 % of acquisitions.ConclusionProspective motion and B0 correction provides high quality repeatable spectra. The study found that most children moved between acquisitions and a substantial number moved during acquisitions. J. Magn. Reson. Imaging 2014;40:958–965. © 2013 Wiley Periodicals, Inc.
Contrast enrichment of spinal cord MR imaging using a ratio of T1‐weighted and T2‐weighted signals
Authors: Teraguchi Masatoshi , Yamada Hiroshi , Yoshida Munehito , Nakayama Yoshiaki , Kondo Tomoyoshi , Ito Hidefumi , Terada Masaki , Kaneoke Yoshiki 
Published: November 2013

PurposeWe aimed to assess if the T1‐weighted (T1w)/T2‐weighted (T2w) signal ratio could be used to improve image contrast in MR spinal cord imaging.Materials and MethodsT1w and T2w cervical spinal cord MR images were acquired from 23 normal subjects using 3 Tesla (T) MR scanner. In addition, a multiple sclerosis patient, and a cervical spondylotic myelopathy patient were evaluated. White matter (WM) and gray matter (GM) signal intensities were measured for each image (T1w, T2w, and T1w/T2w) for seven cervical segments in each subject to calculate the contrast. Age‐related changes in signal intensity were assessed at each location (lateral column, anterior column, dorsal column, and GM) for each image. Additionally, the imaging results of two subjects with spinal diseases and the controls were numerically compared.ResultsThe contrast between the WM and GM in the T1w/T2w ratio image was approximately twice as much as that in the T1w and T2w images (mean ± SD = 1.8 ± 0.4). The signal intensity ratio was related to age. For both clinical patients, the signal intensities were significantly lower in the lesion areas in the ratio images.ConclusionThe T1w/T2w ratio images demonstrated increased image contrast compared with T1w and T2w images alone and, reduced inter‐individual signal intensity differences. J. Magn. Reson. Imaging 2014;40:1199–1207. © 2013 Wiley Periodicals, Inc.
Synoptic climatology of the Ross Ice Shelf and Ross Sea region of Antarctica: k‐means clustering and validation
Authors: Coggins Jack H. J. , McDonald Adrian J. , Jolly Ben 
Published: November 2013

ABSTRACTThe surface wind regime of the Ross Ice Shelf (RIS) is dominated by northward outflow influenced by drainage from both East and West Antarctica and synoptic disturbances over the Ross Sea. To quantify the effects of the wind regime on the climate of the region, we produce a synoptic climatology of the RIS and Ross Sea via a k‐means clustering technique applied to surface (10 m) winds from the ERA Interim reanalysis (1979–2011). We describe the generation of the climatology and discuss composites of surface winds, mean sea‐level pressure and temperature, which show a high degree of internally consistent structure and are similar to previous synoptic climatologies. While some small‐scale features are not fully resolved by the reanalysis, such as the channelling of katabatic flows, we identify a high degree of coherence between clustering results and available in situ data sources, suggesting that the ERA Interim represents the region well. We find that the surface wind field of the ice shelf is highly sensitive to the strength and position of cyclonic disturbances in the Ross Sea, the presence of which can aid outflow from the continental interior. Temperature displays a high level of sensitivity to circulation conditions due to the effects of steep temperature gradients surrounding the shelf and advective heat transport. Cold temperatures on the ice shelf coincide with drainage from East Antarctica, while warmer periods coincide with West Antarctic drainage; this is particularly clear during RIS air stream (RAS) events. The warmest periods occur during southward transport from the Ross Sea. The sensitivity of temperature to the origin of flows suggests circulation changes in the region are likely to significantly impact surface climate. Analysis of the frequency of varying synoptic events and their persistence confirms RAS is a very common and persistent feature of the region.
An aqueous pomegranate seed extract ameliorates oxidative stress of human hepatoma HepG2 cells
Authors: Navarro Marta , Amigo‐Benavent Miryam , Mesias Marta , Baeza Gema , Gökmen Vural , Bravo Laura , Morales Francisco J 
Published: November 2013

AbstractBACKGROUNDAqueous pomegranate seed extract (PSE), a by‐product of the pomegranate juice industry, was recently identified as a potential antiglycative ingredient. Ellagic acid was proposed as the major polyphenol responsible for the antiglycative activity as exerted in in vitro models. However, there is no information on safety aspects of this extract in biological systems before its application as ingredient. The cytotoxicity of PSE (1–100 µg mL−1) was evaluated by determining its effect on cell viability and redox status of cultured HepG2 cells. The protective effect of the PSE against oxidative stress induced by tert‐butyl hydroperoxide (t‐BOOH) was also investigated.RESULTSNo changes in cell integrity or intrinsic antioxidant status resulted from a direct treatment with aqueous PSE, even at high dosage. In addition, reactive oxygen species (ROS) induced by t‐BOOH were reduced by 21% when cells were pretreated with 100 µg mL−1 of aqueous PSE at 180 min. The range of concentrations investigated was effective in decreasing the ROS formation but not in a dose‐dependent manner.CONCLUSIONAqueous pomegranate seed extract enhances human hepatoma cells integrity and resistance to cope with a stressful situation at concentration up to 100 µg mL−1. © 2013 Society of Chemical Industry
Double‐Stimuli‐Responsive Spherical Polymer Brushes with a Poly(ionic liquid) Core and a Thermoresponsive Shell
Authors: Men Yongjun , Drechsler Markus , Yuan Jiayin 
Published: November 2013

The synthesis of poly(ionic liquid) (PIL) nanoparticles grafted with a poly(N‐isopropyl acrylamide) (PNIPAM) brush shell is reported, which shows responsiveness to temperature and ionic strength in an aqueous solution. The PIL nanoparticles are first prepared via aqueous dispersion polymerization of a vinyl imidazolium‐based ionic liquid monomer, which is purposely designed to bear a distal atom transfer radical polymerization (ATRP) initiating group attached to the long alkyl chain via esterification reaction. The size of the PIL nanoparticles can be readily tuned from 25 to 120 nm by polymerization at different monomer concentrations. PNIPAM brushes are successfully grafted from the surface of the poly(ionic liquid) nanoparticles via ATRP. The stimuli‐responsive behavior of the poly(ionic liquid) nanoparticles grafted with PNIPAM brushes (NP‐g‐PNIPAM) in aqueous phase is studied in detail. Enhanced colloidal stability of the NP‐g‐PNIPAM brush particles at high ionic strength compared to pure PIL nanoparticles at room temperature is achieved. Above the lower critical solution temperature (LCST) of PNIPAM, the brush particles remain stable, but a decrease in hydrodynamic radius due to the collapse of the PNIPAM brush onto the PIL nanoparticle surface is observed.
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A Bioeconomic Forest Management Model for the Mediterranean Forests: A Multicriteria Approach
Authors: Martins Maria de Belém , Xavier António , Fragoso Rui 
Published: November 2013

ABSTRACTThe management of forests in the Mediterranean basin is a complex problem, for which many political solutions have been used. In Portugal, these solutions tried to overcome the small property dimension, the elderly and/or absent owners and their relation with new functions and new approaches of forestry areas linked with changes on Common Agricultural Policy and the agriculture development paradigm. The solution must take into account the valorization of all economic activities that exist in the forest, but also the fire risk decreasing and the biodiversity preservation. This paper proposes a model that allows designing several economic scenarios, producing biodiversity and fire risk indicators, but also achieving the best compromise solution between these issues using compromise programming. The model was applied in a Forest Intervention Zone Arade‐Alte/S. B. Messines, in the South of Portugal. The results show that the model is able to provide important information by creating a complete management plan and simulating the best compromise solution among fire risk, economic result and the biodiversity indicator, providing an added background for the analysts. Copyright © 2013 John Wiley & Sons, Ltd.
A MOO‐based Methodology for Designing 3D Stacked Integrated Circuits
Authors: Doan N.A.V. , Milojevic D. , Robert F. , De Smet Y. 
Published: November 2013

ABSTRACTIn the past decades, the micro‐electronic industry has been following the Moore's law to improve the performance of integrated circuits (ICs). However, it will probably be impossible to follow this law in the future due to physical limitations appearing with the miniaturization of the transistors below a certain threshold. In order to overcome this problem, new technologies have emerged, and among them the two‐dimensional stacked integrated circuits (3D‐SIC) have been proposed to keep the Moore's momentum alive. 3D‐SICs can bring numerous advantages in the design of future ICs but at the cost of additional design complexity due to their highly combinatorial nature, and the optimization of several conflicting criteria. In this paper, we present a first study of tools that can help the design of 3D‐SICs, using multi‐objective optimization (MOO). Our study has targeted one of the main issues in the design of 3D‐SICs: the floorplanning. This work shows that the use of MOO can provide relevant and objective analysis of the problem that may not be feasible with the current design methods. MOO can allow a quick design space exploration and an improvement of the current design flows. Also, with its flexibility, MOO can cope with the multiple degrees of freedom of 3D‐SICs, which enables more design possibilities. We believe that these promising results will help designers to overcome the main difficulties of designing 3D‐SICs. Copyright © 2013 John Wiley & Sons, Ltd.
Effects of rasagiline on olfactory function in patients with Parkinson's disease
Authors: Haehner Antje , Hummel Thomas , Wolz Martin , Klingelhöfer Lisa , Fauser Mareike , Storch Alexander , Reichmann Heinz 
Published: November 2013

ABSTRACTBackgroundImpairment of olfactory function is a well‐recognized nonmotor manifestation of Parkinson's disease (PD). The aim of this investigation was to determine if the MAO‐B inhibitor rasagiline can improve olfaction in PD patients.MethodsThirty‐four PD patients participated in this single‐center, prospective, randomized, controlled, double‐blind study. Seventeen patients were randomly assigned to rasagiline and 17 patients to placebo. Ortho‐ and retronasal olfactory testing and recording of event‐related potentials were performed before and after 120 days of rasagiline versus placebo intake.ResultsWhen comparing olfactory score differences between baseline and after 120 days between the 2 groups, the level of significance was not reached.ConclusionsThe primary end point of the study was not reached, and therefore, a specific effect of rasagiline on olfactory function in PD could not be demonstrated. © 2013 International Parkinson and Movement Disorder Society
Primary sleep disorder prevalence in patients with newly diagnosed Parkinson's disease
Authors: Prudon Benjamin , Duncan Gordon W. , Khoo Tien K. , Yarnall Alison J. , Burn David J. , Anderson Kirstie N. 
Published: November 2013

ABSTRACTBackgroundSleep disturbance occurs in up to 96% of patients with established Parkinson's disease (PD). We aimed to assess the prevalence of sleep disturbance in newly diagnosed PD.MethodsNewly diagnosed PD patients and controls were recruited. Patients had motor, non‐motor, and sleep assessments, including sleep questionnaires, respiratory home monitoring, actigraphy, and sleep diaries. Controls completed cognitive assessments, sleep questionnaires, and diaries.ResultsA total of 106 patients and 99 controls participated. Sleep questionnaire scores were no different between patients and controls. Daytime naps were increased in PD patients on sleep diaries (P > 0.003). Sleepiness was not associated with any motor or non‐motor symptom. Periodic limb movements were increased but not associated with restless legs.ConclusionsNewly diagnosed PD patients had minimal differences in subjective or objective sleep disturbance compared to controls apart from increased daytime naps and symptoms such as dream‐enacting behaviors of punching or grabbing. This contrasts with the literature assessing sleep in those with established PD.© 2013 International Parkinson and Movement Disorder Society
Modelling rigid line and Dirichlet boundary conditions with arbitrary geometry by intrinsic XFEM
Authors: Rashvand A. 
Published: November 2013

SUMMARYThe most difficult aspect of modelling discontinuity on complicated domains is the mesh. In the extended finite element method (XFEM), the FE mesh need not conform to the internal boundaries. In the intrinsic XFEM, no additional unknowns are introduced at the nodes. Some of these discontinuities such as cracks, voids were developed in earlier papers. In the current work, the FE mesh is allowed to be independent of the rigid line (fixed DOFs path). Copyright © 2013 John Wiley & Sons, Ltd.
A goal‐oriented hp‐adaptive discontinuous Galerkin approach for biharmonic problems
Authors: Gonçalves João L. , Gomes Sônia M. , Devloo Philippe R.B. 
Published: November 2013

SUMMARYA goal‐oriented algorithm is developed and applied for hp‐adaptive approximations given by the discontinuous Galerkin finite element method for the biharmonic equation. The methodology is based on the dual problem associated with the target functional. We consider three error estimators and analyse their properties as basic tools for the design of the hp‐adaptive algorithm. To improve adaptation, the combination of two different error estimators is used, each one at its best efficiency, to guide the tasks of where and how to adapt the approximation spaces. The performance of the resulting hp‐adaptive schemes is illustrated by numerical experiments for two benchmark problems. Copyright © 2013 John Wiley & Sons, Ltd.
From Birth to School: Early Childhood Initiatives and Third‐Grade Outcomes in North Carolina
Authors: Ladd Helen F. , Muschkin Clara G. , Dodge Kenneth A. 
Published: November 2013

AbstractThis study examines the community‐wide effects of two statewide early childhood policy initiatives in North Carolina. One initiative provides funding to improve the quality of child care services at the county level for all children between the ages of 0 to 5, and the other provides funding for preschool slots for disadvantaged four‐year‐olds. Differences across counties in the timing of the rollout and in the magnitude of the state financial investments per child provide the variation in programs needed to estimate their effects on schooling outcomes in third grade. We find robust positive effects of each program on third‐grade test scores in both reading and math. These effects can best be explained by a combination of direct benefits for participants and spillover benefits for others. Our preferred models suggest that the combined average effects on test scores of investments in both programs at 2009 funding levels are equivalent to two to four months of instruction in grade 3.