bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of hypopharyngeal carcinoma using high‐resolution ultrasound: Comparison with CT
Authors: Dhoot Nilu M. , Singh Shobit , Choudhury Binoy , Kataki Amal C. , Kalita Nripati K. , Bhattacharyya Mouchumee , Kalita Apurba 
Published: January 2014

ABSTRACTBackgroundTo evaluate the role of sonography (US) in assessing hypopharyngeal carcinoma when compared with CT.MethodsA randomized prospective study was performed on 40 biopsy‐proven cases of hypopharyngeal carcinoma.Contrast‐enhanced CT of the neck was performed in all patients, followed by US. Sonographic identification of any tumor extension into the extralaryngeal soft tissues, postcricoid space, subglottis, thyroid gland, esophagus, and across the midline was recorded. US observations and CT findings were compared and then correlated with the histopathologic findings in 14 operative cases. In the remaining 26 inoperable cases, US was compared only with CT.ResultsOur cohort was composed of 38 men and 2 women ranging in age from 36 to 59 years. In a subset of 14 operative patients, US had a sensitivity of 71.4% (10/14), while CT achieved a sensitivity of 92.8% (13/14), and the difference was not statistically significant (p > 0.05). US and CT findings concurred in 67.5% (27/40) of cases.ConclusionsEven though small tumors are difficult to visualize, US can play a significant role in the assessment of tumor extension within and beyond the larynx, especially when cross‐sectional imaging is either unavailable or unaffordable. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound 42:143–149, 2014
In vitro assessment of the lenz effect on heart valve prostheses at 1.5 T
Authors: Edwards Maria‐Benedicta , Mclean John , Solomonidis Stephanos , Condon Barrie , Gourlay Terence 
Published: January 2014

PurposeIncreasing numbers of patients with cardiac valve prostheses are being referred for magnetic resonance imaging (MRI) despite concerns about the potential for functional valve impedance due to Lenz forces. This study aims to determine, in vitro, the occurrence of Lenz forces on 9 heart valve prostheses at 1.5 T and assess the risk of impedance of valve function.Materials and MethodsA specially designed hydro‐pneumatic system was used to record pressure changes across the valve indicative of any MR induced alteration in leaflet performance. Nine cardiac valve prostheses were exposed to the B0 field at 1.5 T. Each valve was advanced through the B0 field and continuous signals from high frequency pressure transducers were recorded and pressure drops across the valve were assessed using time correction superimposition. The delta p across the valve was assessed as a marker of any MRI induced alteration in leaflet performance.ResultsAll prostheses produced sinusoidal waveforms. Profiles were asymmetrical and there was no consistency in complex shape and valve type/sub‐group. Irregularities in pressure profiles of 4 prostheses were detected indicating resistance of the occluder to the B0 field.ConclusionThis study provides empirical evidence of the Lenz Effect on cardiac valve prostheses exposed to the MR B0 field causing functional valve impedance and increasing the risk of valvular regurgitation and reduced cardiac output. Thus, it is essential to consider the potential for the Lenz Effect when scanning cardiac valve implant patients in order to safeguard their wellbeing. J. Magn. Reson. Imaging 2015;41:74–82. © 2013 Wiley Periodicals, Inc.
Volumetric arterial wall shear stress calculation based on cine phase contrast MRI
Authors: Potters Wouter V. , van Ooij Pim , Marquering Henk , vanBavel Ed , Nederveen Aart J. 
Published: January 2014

PurposeTo assess the accuracy and precision of a volumetric wall shear stress (WSS) calculation method applied to cine phase contrast magnetic resonance imaging (PC‐MRI) data.Materials and MethodsVolumetric WSS vectors were calculated in software phantoms. WSS algorithm parameters were optimized and the influence of spatial resolution and segmentation was evaluated. Subsequently, 2D cine PC‐MRI data in the carotid and the aorta at varying spatial resolutions were obtained (n = 2) and compared with the simulations. Finally, volumetric WSS was calculated in 3D cine PC‐MRI data of the carotid bifurcation and the aorta (n = 6).ResultsWe found that at least 8 voxels across the diameter are required to obtain a WSS accuracy of 5% and a precision of 20% in software phantoms. Systematic WSS quantification errors up to 40% were found in the case of segmentation errors. The in vivo measurements using 2D cine PC‐MRI exhibited WSS increase at increasing spatial resolutions, similar to the results in software phantoms. Volumetric WSS vectors were successfully calculated in three healthy carotid bifurcations and aortas.ConclusionThe effects of resolution and segmentation on the accuracy and precision of the WSS algorithm were quantified. We were able to calculate volumetric WSS in the carotid bifurcation and the aorta. J. Magn. Reson. Imaging 2015;41:505–516.© 2013 Wiley Periodicals, Inc.
Validation of a semiautomated spinal cord segmentation method
Authors: El Mendili Mohamed‐Mounir , Chen Raphaël , Tiret Brice , Pélégrini‐Issac Mélanie , Cohen‐Adad Julien , Lehéricy Stéphane , Pradat Pierre‐François , Benali Habib 
Published: January 2014

PurposeTo validate semiautomated spinal cord segmentation in healthy subjects and patients with neurodegenerative diseases and trauma.Materials and MethodsForty‐nine healthy subjects, as well as 29 patients with amyotrophic lateral sclerosis, 19 with spinal muscular atrophy, and 14 with spinal cord injuries were studied. Cord area was measured from T2‐weighted 3D turbo spin echo images (cord levels from C2 to T9) using the semiautomated segmentation method of Losseff et al (Brain [1996] 119(Pt 3):701–708), compared with manual segmentation. Reproducibility was evaluated using the inter‐ and intraobserver coefficient of variation (CoV). Accuracy was assessed using the Dice similarity coefficient (DSC). Robustness to initialization was assessed by simulating modifications to the contours drawn manually prior to segmentation.ResultsMean interobserver CoV was 4.00% for manual segmentation (1.90% for Losseff's method) in the cervical region and 5.62% (respectively 2.19%) in the thoracic region. Mean intraobserver CoV was 2.34% for manual segmentation (1.08% for Losseff's method) in the cervical region and 2.35% (respectively 1.34%) in the thoracic region. DSC was high (0.96) in both cervical and thoracic regions. DSC remained higher than 0.8 even when modifying initial contours by 50%.ConclusionThe semiautomated segmentation method showed high reproducibility and accuracy in measuring spinal cord area. J. Magn. Reson. Imaging 2015;41:454–459.© 2013 Wiley Periodicals, Inc.
Neurochemical correlates of caudate atrophy in Huntington's disease
Authors: Padowski Jeannie M. , Weaver Kurt E. , Richards Todd L. , Laurino Mercy Y. , Samii Ali , Aylward Elizabeth H. , Conley Kevin E. 
Published: January 2014

ABSTRACTThe precise pathogenic mechanisms of Huntington's disease (HD) are unknown but can be tested in vivo using proton magnetic resonance spectroscopy (1H MRS) to measure neurochemical changes. The objective of this study was to evaluate neurochemical differences in HD gene mutation carriers (HGMCs) versus controls and to investigate relationships among function, brain structure, and neurochemistry in HD. Because previous 1H MRS studies have yielded varied conclusions about HD neurochemical changes, an additional goal was to compare two 1H MRS data analysis approaches. HGMCs with premanifest to early HD and controls underwent evaluation of motor function, magnetic resonance imaging, and localized 1H MRS in the caudate and the frontal lobe. Analytical approaches that were tested included absolute quantitation (unsuppressed water signal as an internal reference) and relative quantification (calculating ratios of all neurochemical signals within a voxel). We identified a suite of neurochemicals that were reduced in concentration proportionally to loss of caudate volume in HGMCs. Caudate concentrations of N‐acetylaspartate (NAA), creatine, choline, and caudate and frontal lobe concentrations of glutamate plus glutamine (Glx) and glutamate were correlated with caudate volume in HGMCs. The relative, but not the absolute, quantitation approach revealed disease‐related differences; the Glx signal was decreased relative to other neurochemicals in the caudate of HGMCs versus controls. This is the first study to demonstrate a correlation among structure, function, and chemical measures in HD brain. Additionally, we demonstrate that a relative quantitation approach may enable the magnification of subtle differences between groups. Observation of decreased Glx suggests that glutamate signaling may be disrupted relatively early in HD, which has important implications for therapeutic approaches. © 2014 International Parkinson and Movement Disorder Society
Breathing variability and brainstem serotonergic loss in a genetic model of multiple system atrophy
Authors: Flabeau Olivier , Meissner Wassilios G. , Ozier Annaig , Berger Patrick , Tison François , Fernagut Pierre‐Olivier 
Published: January 2014

ABSTRACTBreathing disorders like sleep apnea, stridor, and dysrythmic breathing are frequent in patients with multiple system atrophy (MSA). These observations have been related to neurodegeneration in several pontomedullary respiratory nuclei and may explain the occurrence of sudden death. In this study, we sought to determine whether these functional and neuropathological characteristics could be replicated in a transgenic model of MSA. Mice expressing human wild‐type α‐synuclein under the control of the proteolipid promoter (PLP‐αSYN) were compared with age‐matched controls. Using whole‐body, unrestrained plethysmography, the following breathing parameters were measured: inspiratory and expiratory times, tidal volume, expiratory volume, peak inspiratory and expiratory flows, and respiratory frequency. For each category, the mean, coefficient of variation, and irregularity score were analyzed. Brains were then processed for stereological cell counts of pontomedullary respiratory nuclei. A significant increase in the coefficient of variation and irregularity score was observed for inspiratory time, tidal volume, and expiratory volume in PLP‐αSYN mice (P < 0.05). Glial cytoplasmic inclusions were found in the medullary raphe of PLP‐αSYN mice, together with a loss of serotonergic immunoreactivity in the raphe obscurus (P < 0.001) and pallidus (P < 0.01). There was a negative correlation between α‐synuclein burden and raphe pallidus cell counts (P < 0.05). There was no significant neuronal loss in the pre‐Botzinger complex. The PLP‐αSYN mouse model replicates the breathing variability and part of the neuronal depletion in pontomedullary respiratory nuclei observed in patients with MSA. Our findings support the use of this model for future candidate drugs in the breathing disorders observed in MSA. © 2014 International Parkinson and Movement Disorder Society
Microstructural origins of gadolinium‐enhanced susceptibility contrast and anisotropy
Authors: Dibb Russell , Li Wei , Cofer Gary , Liu Chunlei 
Published: January 2014

PurposeMR histology based on magnetic susceptibility can be used to visualize diamagnetic myelin (and its deterioration) in the central nervous system and is facilitated by the application of high magnetic field strengths and paramagnetic contrast agents. Characterizing the effect of these tools will aid in assessing white matter myelin content and microstructure.MethodsImage data from six gadolinium‐perfused mouse brain specimens were acquired at 2.0, 7.0, and 9.4 Tesla. Magnetic susceptibility contrast was analyzed for its dependence on field strength, gadolinium concentration, and white matter fiber orientation. A model for this contrast is presented based on the three‐pool model for white matter.ResultsThe specimen data illustrate that white–gray matter susceptibility contrast is field strength independent. White–gray matter contrast improves significantly as a function of gadolinium contrast agent in the tissue, i.e., white matter appears increasingly more diamagnetic relative to gray matter. The simulated data from the model suggest that susceptibility anisotropy of white matter fiber bundles increases nonlinearly as a function of gadolinium concentration due to contrast agent compartmentalization into the extracellular white matter water pool.ConclusionUsing contrast agents in MR histology facilitates white–gray matter susceptibility contrast modulation and the probing of white matter microstructure and orientation. Magn Reson Med 72:1702–1711, 2014. © 2014 Wiley Periodicals, Inc.
Induction of adipocyte hyperplasia in subcutaneous fat depot alleviated type 2 diabetes symptoms in obese mice
Authors: Lu Qiqi , Li Mingming , Zou Yu , Cao Tong 
Published: January 2014

ObjectiveThe role of subcutaneous adipose tissue (SAT) in the pathogenesis of type 2 diabetes is still under controversy. In this study, the metabolic effects of inducing adipocyte hyperplasia in SAT depots in obese mice were investigated.MethodsHigh fat diet was used to induce obesity and type 2 diabetes symptoms in C57BL6/J mice. To induce SAT expansion through hyperplasia, acellular adipogenic cocktails were injected around the SAT depots in high fat diet‐induced obese mice.ResultsTen weeks after injections, significant neoadipogenesis was induced, which not only obviously expanded the volume of SATs but also significantly increased the adipocyte density within the whole SAT depots. Importantly, these mice exhibited improved glucose tolerance and insulin sensitivity (homeostatic model assessment) when compared to control group. Further studies suggested that these beneficial metabolic effects were associated with elevation of serum high‐molecular‐weight adiponectin level and reduction of ectopic lipid accumulation in liver.ConclusionsThese findings not only further supported the protective role of SAT in the pathogenesis of type 2 diabetes but also highlighted the importance of adipocyte hyperplasia in this protective effect.
Intravenous magnesium for pediatric sickle cell vaso‐occlusive crisis: Methodological issues of a randomized controlled trial
Authors: Badaki‐Makun Oluwakemi , Scott J. Paul , Panepinto Julie A. , Casper T. Charles , Hillery Cheryl A. , Dean J. Michael , Brousseau David C. ,   for the Pediatric Emergency Care Applied Research Network (PECARN) Magnesium in Sickle Cell Crisis (MAGiC) Study Group
Published: January 2014

AbstractMultiple recent Sickle Cell Disease studies have been terminated due to poor enrollment. We developed methods to overcome past barriers and utilized these to study the efficacy and safety of intravenous magnesium for vaso‐occlusive crisis (VOC). We describe the methods of the Intravenous Magnesium in Sickle Vaso‐occlusive Crisis (MAGiC) trial and discuss methods used to overcome past barriers. MAGiC was a multi‐center randomized double‐blind placebo‐controlled trial of intravenous magnesium versus normal saline for treatment of VOC. The study was a collaboration between Pediatric Hematologists and Emergency Physicians in the Pediatric Emergency Care Applied Research Network (PECARN). Eligible patients were randomized within 12 hours of receiving intravenous opioids in the Emergency Department (ED) and administered study medication every 8 hours. The primary outcome was hospital length of stay. Associated plasma studies elucidated magnesium's mechanism of action and the pathophysiology of VOC. Health‐related quality of life was measured. Site‐, protocol‐, and patient‐related barriers from prior studies were identified and addressed. Limited study staff availability, lack of collaboration with the ED, and difficulty obtaining consent were previously identified barriers. Leveraging PECARN resources, forging close collaborations between Sickle Cell Centers and EDs of participating sites, and approaching eligible patients for prior consent helped overcome these barriers. Participation in the PECARN network and establishment of collaborative arrangements between Sickle Cell Centers and their affiliated EDs are major innovative features of the MAGiC study that allowed improved subject capture. These methods could serve as a model for future studies of VOCs. Pediatr Blood Cancer 2014;61:1049–1054. © 2014 Wiley Periodicals, Inc.
Outcome of children treated for relapsed acute myeloid leukemia in Central America
Authors: Marjerrison Stacey , Antillon Federico , Bonilla Miguel , Fu Ligia , Martinez Roxana , Valverde Patricia , Vasquez Roberto , Howard Scott C. , Ribeiro Raul C. , Sung Lillian 
Published: January 2014

BackgroundRelapsed childhood acute myeloid leukemia (AML) outcomes have not been documented in resource‐limited settings. We examined survival after relapse for children with AML (non‐APML) and acute promyelocytic leukemia (APML) in Central America.ProcedureWe retrospectively evaluated outcomes of children with first relapse of AML (non‐APML) and APML in Guatemala, Honduras, or El Salvador diagnosed between 1997 and 2011. Predictors of subsequent event‐free survival (EFS) and overall survival (OS) were examined.ResultsWe identified 140 children with relapsed AML (non‐APML), and 24 with relapsed APML. Two‐year subsequent EFS and OS (±SE) were 7.0 ± 2.5% and 9.1 ± 2.8%, respectively. Worse outcomes were associated with Hispanic or Indigenous heritage, white blood cell count at diagnosis ≥50 × 109/L, and time to relapse <18 months. For those with relapsed APML, subsequent 2‐year EFS and OS were 36.7 ± 10.8% and 43.4 ± 12.1%, although few patients survived beyond 3 years. 15.2% of all patients were managed solely with palliative intent following first relapse.ConclusionsChildren with relapsed AML in Central America rarely survive, so palliative strategies should be considered following relapse in this population. However, children with late relapse or with APML may have a prolonged period of remission with second treatment, and consideration of re‐treatment may be appropriate. Pediatr Blood Cancer 2014;61:1222–1226. © 2014 Wiley Periodicals, Inc.
Role of the second‐trimester ‘genetic sonogram’ for Down syndrome screen in the era of first‐trimester screening and noninvasive prenatal testing
Authors: Odibo Anthony O. , Ghidini Alessandro 
Published: January 2014

ABSTRACTUltrasonography for the screening of Down syndrome was first introduced about 25 years ago. Different combinations of markers detectable at second‐trimester ultrasonography have been proposed under the banner of ‘genetic sonogram’. In recent years, several developments in first‐trimester screening and the recent introduction of noninvasive prenatal testing for aneuploidy screening have had important implications for the prevalence of these conditions in the second‐trimester and the screening performance of a genetic sonogram. Several second‐trimester sonographic markers for Down syndrome have been reported; meta‐analysis has shown that the most powerful predictors are mild ventriculomegaly, increased nuchal fold, hyperechoic bowel, and absent or hypoplastic nasal bone. Whereas use of individual markers should be discouraged and scoring systems of multiple markers are now obsolete, use of combined likelihood ratio and logistic regression analysis formulae provides better accuracy. However, there is significant heterogeneity in results among studies. Despite such limitations, the genetic sonogram will continue to have a place in prenatal screening, particularly in twin and higher‐order multiple pregnancies, in countries with limited access to the most recent genetic screening tests, in cases with borderline results at maternal serum screening tests, and as noninvasive supplementary test for high‐risk women reluctant to undergo invasive diagnostic testing. © 2014 John Wiley & Sons, Ltd.
The nano‐mechanics and magnetic properties of high moment synthetic antiferromagnetic particles
Authors: Forrester Michael , Kusmartsev Feodor 
Published: January 2014

With nanomagnets increasingly being used and proposed as functional units for in vivo applications, it is vital to understand how to optimize their structure, geometry, and size, and their responses to electromagnetic stimulation. Herein, we predicate how to do so for synthetic antiferromagnetic structures that are subjected to external magnetic control. Because the structures are on the scale of biological entities, interactions with cells and molecular constituents can be extreme and careful design must be undertaken to avoid detrimental effects. Thus, the magnetic responses of multilayers, as demonstrated in experiments by Koh et al. [e.g., Hu et al., Adv. Mater. 20, 1479 (2008) and Koh et al., J. Appl. Phys. 107, 09B522 (2010)], are understood using a fully dynamical investigation based on Landau–Lifshitz–Gilbert equations. We find that during the fabrication of the structures the axial positions of the nanomagnets become offset from each other, leading to the characteristic magnetic hysteresis shapes witnessed. We then find the magnetic nano‐mechanical forces generated by such structures. The conical synthetic antiferromagnetic nanoparticles with two magnetic layers – Left: the magnetic flux density is shown on the surface of the structure in a magnetic flux density of B = 0.08 T. Middle and right: orientations of the magnetic moments of the two magnetic layers.
Balance and randomness in sequential clinical trials: the dominant biased coin design
Authors: Antognini Alessandro Baldi , Zagoraiou Maroussa 
Published: January 2014

AbstractEfron's biased coin design (BCD) is a well‐known randomization technique that helps neutralize selection bias, while keeping the experiment fairly balanced for every sample size. Several extensions of this rule have been proposed, and their properties were analyzed from an asymptotic viewpoint and compared via simulations in a finite setup. The aim of this paper is to push forward these comparisons by taking also into account the adjustable BCD, which is never considered up to now. Firstly, we show that the adjustable BCD performs better than Efron's coin with respect to both loss of precision and randomness. Moreover, the adjustable BCD is always more balanced than the other coins and, only for some sample sizes, slightly more predictable. Therefore, we suggest the dominant BCD, namely a new and flexible class of procedures that can change the allocation rule step by step in order to ensure very good performance in terms of both balance and selection bias for any sample size. Our simulations demonstrate that the dominant BCD is more balanced and, at the same time, less or equally predictable than Atkinson's optimum BCD. Copyright © 2014 John Wiley & Sons, Ltd.
Obtaining K‐obfuscation for profile privacy in social networks
Authors: Liu Xiangyu , Wang Bin , Yang Xiaochun , Yu Meng , Zang Wanyu 
Published: January 2014

ABSTRACTThe increasing popularity of social networks in various application domains has raised privacy concerns for the individuals involved. In this work, we formally present the definition of profile privacy leakage, which is a newly identified privacy leakage in social networks. However, applying existing methods straightforwardly cannot provide efficient privacy protection for the profiles meanwhile incurring a large amount of information loss. We propose k‐obfuscation to protect profiles against graph property based attacks. We develop a general framework for obtaining k‐obfuscation. In this framework, we propose a novel safe vertex‐profile mapping mechanism, named as k‐mapping. We also design a number of techniques to make the k‐mapping method efficient meanwhile maintaining the data utilities. Extensive experiments on real datasets show the satisfactory performance of our methods in terms of privacy protection, efficiency, and practical utilities. Copyright © 2014 John Wiley & Sons, Ltd.