bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sparsity and low‐contrast object detectability
Authors: Trzasko Joshua D. , Bao Zhonghao , Manduca Armando , McGee Kiaran P. , Bernstein Matt A. 
Published: September 2011

AbstractThe application of sparsity‐driven reconstruction methods to MRI to date has largely focused on situations where high‐contrast features (e.g., gadolinium‐enhanced vessels) are of primary interest. In clinical practice, however, low contrast features such as subtle lesions are often of equal or greater interest. Using an American College of Radiology MR quality assurance phantom and test, we describe a novel framework for systematically and automatically evaluating the low‐contrast object detectability performance of different undersampled image reconstruction methods. This platform is used to evaluate three such methods, two based on classic Tikhonov regularization and one sparsity‐driven method based on ℓ1‐norm minimization (which is commonly used in compressive sensing, also known as compressed sensing, applications), across a wide range of sampling rates and parameterizations. Both the automated evaluation system and a manual evaluation of anatomical images with numerically‐generated low contrast inserts demonstrate that sparse reconstructions exhibit superior low‐contrast object detectability performance compared to both Tikhonov‐regularized reconstructions. The implications of this result, and potential applications of both the described low‐contrast object detectability platform and generalizations of it are then discussed. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Generalized spatiotemporal myocardial strain analysis for DENSE and SPAMM imaging
Authors: Young Alistair A. , Li Bo , Kirton Robert S. , Cowan Brett R. 
Published: September 2011

AbstractDisplacement encoding using stimulated echoes (DENSE) and spatial modulation of magnetization (SPAMM) are MRI techniques for quantifying myocardial displacement and strain. However, DENSE has not been compared against SPAMM in phantoms exhibiting nonhomogeneous strain, and interobserver variability has not been compared between DENSE and SPAMM. To perform these comparisons, there is a need for a generalized analysis framework for the evaluation of myocardial strain. A spatiotemporal mathematical model was used to represent myocardial geometry and motion. The model was warped to each frame using tissue displacement maps calculated from either automated phase unwrapping (DENSE) or nonrigid registration (SPAMM). Strain and motion were then calculated from the model using standard methods. DENSE and SPAMM results were compared in a deformable gel phantom exhibiting known nonhomogeneous strain, and interobserver errors were determined in 19 healthy human volunteers. Nonhomogeneous strain in the phantom was accurately quantified using both DENSE and SPAMM. In the healthy volunteers, DENSE produced better interobserver errors than SPAMM for radial strain (−0.009 ± 0.069 vs. 0.029 ± 0.152, respectively, bias ±95% confidence interval). In conclusion, generalized spatiotemporal modeling enables robust myocardial strain analysis for DENSE or SPAMM. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Subject‐specific estimation of respiratory navigator tracking factor for free‐breathing cardiovascular MR
Authors: Moghari Mehdi H. , Hu Peng , Kissinger Kraig V. , Goddu Beth , Goepfert Lois , Ngo Long , Manning Warren J. , Nezafat Reza 
Published: September 2011

AbstractA mean respiratory navigator tracking factor of 0.6 is commonly used to estimate the respiratory motion of the heart from the displacement of the right hemi‐diaphragm. A constant tracking factor can generate significant residual error in estimation of the respiratory motion of the heart for the cases where the actual tracking factor highly deviates from 0.6. In this study, we implemented and evaluated a robust method to calculate a subject‐specific tracking factor for free‐breathing high resolution cardiac MR. The subject‐specific tracking factor was calculated from two consecutive navigator signals placed on the right hemi‐diaphragm and the basal left ventricle in a training phase. To verify the accuracy of the estimated subject‐specific tracking factor, nineteen subjects were recruited for comparing the estimated tracking factor in real‐time with an image‐based tracking factor, calculated off‐line. Subsequently, in seven adult subjects, whole‐heart or targeted coronary artery MR images were acquired using the estimated subject‐specific tracking factor and visually compared with those acquired using a constant (0.6) tracking factor. It was shown that the proposed method can accurately estimate the subject‐specific tracking factor and improve the quality of coronary images when the subject‐specific tracking factor differs from 0.6. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Discrimination of spinal and bulbar muscular atrophy from amyotrophic lateral sclerosis using sensory nerve action potentials
Authors: Hama Tetsuo , Hirayama Masaaki , Hara Takashi , Nakamura Tomohiko , Atsuta Naoki , Banno Haruhiko , Suzuki Keisuke , Katsuno Masahisa , Tanaka Fumiaki , Sobue Gen 
Published: September 2011

AbstractIntroduction:Spinal and bulbar muscular atrophy (SBMA) and amyotrophic lateral sclerosis (ALS) are motor neuron diseases. Sensory impairment is sometimes observed, and electrophysiological involvement has been described in the sensory nerves of SBMA patients. We hypothesized that a sensory nerve conduction study (NCS) could be used to discriminate SBMA from ALS.Methods:We compared the results from NCSs in a total of 120 SBMA cases confirmed by genetic analysis, 188 ALS cases, and 50 normal subjects.Results:Sensory nerve action potential (SNAP) amplitudes of the SBMA group were significantly lower than in the ALS and control groups. In addition, receiver‐operating characteristic curve analysis for SNAP amplitude showed that a cut‐off value of 13.8 μV for median, 10.7 μV for ulnar, and 9.9 μV for sural nerve best discriminated SBMA from ALS.Conclusions:The specific decrease of SNAP amplitude in SBMA provides another useful tool for the differential diagnosis of motor neuron diseases. Muscle Nerve, 2012
Relapsed acute myelogenous leukemia of brachial plexus after marrow transplant
Authors: Sweet Jennifer A. , Jones Robert V. , Siu Alan , DePalma Louis , Caputy Anthony J. 
Published: September 2011

AbstractWe present a detailed description of brachial plexus infiltration by acute myelogenous leukemia (AML) in the setting of a remission bone marrow biopsy, without evidence of leukemia by flow cytometric analysis. This case illustrates the possibility of dormant leukemic cells in the peripheral nervous system (PNS) in a patient in apparent clinical remission. In patients with an unexplained brachial plexopathy and a history of AML, leukemic infiltrate of the PNS must be considered. Muscle Nerve, 2012
Variational multiscale enrichment for modeling coupled mechano‐diffusion problems
Authors: Oskay Caglar 
Published: September 2011

SUMMARYIn this paper, a new multiscale–multiphysics computational methodology is devised for the analysis of coupled diffusion–deformation problems. The proposed methodology is based on the variational multiscale principles. The basic premise of the approach is accurate fine‐scale representation at a small subdomain where it is known a priori that important physical phenomena are likely to occur. The response within the remainder of the problem domain is idealized on the basis of coarse‐scale representation. We apply this idea to evaluate a coupled mechano‐diffusion problem that idealizes the response of titanium structures subjected to a thermo–chemo–mechanical environment. The proposed methodology is used to devise a multiscale model in which the transport of oxygen into titanium is modeled as a diffusion process, whereas the mechanical response is idealized using concentration‐dependent elasticity equations. A coupled solution strategy based on operator split is formulated to evaluate the coupled multiphysics and multiscale problem. Numerical experiments are conducted to assess the accuracy and computational performance of the proposed methodology. Numerical simulations indicate that the variational multiscale enrichment has reasonable accuracy and is computationally efficient in modeling the coupled mechano‐diffusion response. Copyright © 2011 John Wiley & Sons, Ltd.
Superconvergence analysis for time‐dependent Maxwell's equations in metamaterials
Authors: Huang Yunqing , Li Jichun , Lin Qun 
Published: September 2011

AbstractIn this article, we consider the time‐dependent Maxwell's equations modeling wave propagation in metamaterials. One‐order higher global superclose results in the L2 norm are proved for several semidiscrete and fully discrete schemes developed for solving this model using nonuniform cubic and rectangular edge elements. Furthermore, L∞ superconvergence at element centers is proved for the lowest order rectangular edge element. To our best knowledge, such pointwise superconvergence result and its proof are original, and we are unaware of any other publications on this issue. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential 2011
Correlates of stages of change for physical activity in adults with multiple sclerosis
Authors: Plow Matthew A. , Finlayson Marcia , Cho Chi 
Published: September 2011

AbstractThe Transtheoretical Model (TTM) is commonly used to understand physical activity (PA) behavior in the general population; however, few researchers have explored its relevance for persons with multiple sclerosis (MS). We examined the relative importance of health (symptoms and mobility impairments) and TTM constructs (behavioral and cognitive processes of change) in influencing stages of change placement for PA in a sample of 303 persons with MS using discriminant function analysis. The overall accuracy of predicting stages of change was 58.75%. Behavioral (r2 = .35) and cognitive processes (r2 = .17) accounted for the most variance, followed by mobility (r2 = .11) and self‐efficacy (r2 = .05). Results provide support for evaluating whether TTM‐based interventions can promote PA in adults with MS. © 2011 Wiley Periodicals, Inc. Res Nurs Health 34:378–388, 2011
Graphene nanocomposites based on poly(vinylidene fluoride): Structure and properties
Authors: Yu Jinhong , Jiang Pingkai , Wu Chao , Wang Lichun , Wu Xinfeng 
Published: September 2011

AbstractA nanocomposite of Poly(vinylidene fluoride) (PVDF) was prepared with graphene sheets (GSs), which are a novel filler by a solution method. The structure‐properties relationships of PVDF/GSs nanocomposites were studied. The results of differential scanning calorimetry and X‐ray diffraction show that addition of GSs to the PVDF matrix promotes an α phase to β phase transformation of the polymer crystal. The nanocomposites exhibit significant increases in dynamic mechanical properties and thermal stability compared to the neat PVDF. In addition, the incorporation of GSs in PVDF indicated excellent optical transparency at the lowest weight fractions of GSs and modified wettability of PVDF. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Toughening effect of cellulose nanowhiskers on polyvinyl acetate: Fracture toughness and viscoelastic analysis
Authors: Gong Guan , Mathew Aji P. , Oksman Kristiina 
Published: September 2011

AbstractThe toughening effect of cellulose nanowhiskers (CNWs) on modified polyvinyl acetate (PVAc) was analyzed with the help of morphology, relaxation, and creep behavior. The CNWs together with bound moisture at the matrix/whisker interfaces resulted in significant improvement in resistance to crack initiation and propagation. The magnitude of plastic deformation of the nanocomposites was higher than that of the neat PVAc. The relaxation temperature decreased, while the width of the damping peak increased with increasing CNW and moisture contents. The results from creep modeling showed that the instantaneous elastic modulus first increased and then decreased with the addition of CNWs, while the time‐dependent elasticity and viscosity decreased. The results suggested that the reinforcing effect of the CNWs was overwhelmed by the plasticizing effect of the bound moisture. Furthermore, low concentrations of CNWs significantly improved the fracture toughness of PVAc at the minor cost of strength, stiffness, and creep resistance. In this article, we present a novel approach to studying the toughening effect of CNWs on polymers using fracture tests and viscoelastic modeling. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Centrifugal partition chromatography in the separation of natural products
Authors: Marston A. , Slacanin I. , Hostettmann K. 
Published: September 2011

AbstractRecent innovations in liquid/liquid chromatographic techniques have led to a resurgence of interest in their use for the separation of natural products. Commercially available instruments which rely on centrifugal acceleration to speed up separation times are based either on a battery of cartridges or on a rotating multilayer coil and can be employed either as analytical tools or for preparative purposes. While solvent consumption is low, milligram to gram quantities are capable of being separated. Aqueous and non‐aqueous two‐phase solvent systems are compatible with these techniques and numerous applications involving simple and complex mixtures of natural products, both polar and non‐polar, have been demonstrated.
Quantitative glucosinolate analysis in Brassica seeds by X‐ray fluorescence spectroscopy
Authors: Schnug E. , Haneklaus S. 
Published: September 2011

AbstractX‐ray fluorescence spectroscopy (X‐RF) is an indirect method which is suitable for the quantification of the total glucosinolate content of Brassica seeds. The X‐RF method is based on two major principles: the close relationship between total sulphur and total glucosinolate content in rapeseed and the distinctive applicabilities of X‐ray fluorescence spectroscopy for total sulphur determination in organic matter. The whole preparation procedure consists of only three steps and needs less than five minutes per sample. A special advantage of the method is the availability of a centralized calibration system which ensures the comparability of data derived from different laboratories.
Modeling the continuous entrapment and growth of gas bubbles during bulk polymerization of methyl methacrylate
Authors: Sahni Hitesh , Gupta Santosh K. , Mehra Anurag 
Published: September 2011

AbstractGas bubbles get entrapped continuously during bulk polymerization in stirred batch reactors. Once entrapped, these cannot escape because of the increasing viscosity of the reaction mass. The bubbles also grow with time due to the diffusion of the monomer. This phenomenon is modeled using an Eulerian‐Lagrangian population‐balance approach along with the equations describing the kinetics of polymerization. It is assumed that there is no nucleation of bubbles. An empirical rate of entrapment, Rentrap,i(viscosity, bubble diameter) is assumed for the polymerization of methyl methacrylate (MMA), an example system. The model parameters are tuned using experimental data on this system under near‐isothermal conditions in a 1‐L, fully instrumented stainless steel reactor with an anchor agitator. The model predictions are found to be in reasonable accord with experimental data under different conditions of polymerization. The study of this phenomenon has important design implications since the pre‐polymerization stage ends as soon as stable clusters of bubbles get formed. Further polymerization is normally carried out in tubular reactors or in molds. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Protein modulation in mouse heart under acute and chronic hypoxia
Authors: Viganò Agnese , Vasso Michele , Caretti Anna , Bravatà Valentina , Terraneo Laura , Fania Chiara , Capitanio Daniele , Samaja Michele , Gelfi Cecilia 
Published: September 2011

AbstractExploring cellular mechanisms underlying beneficial and detrimental responses to hypoxia represents the object of the present study. Signaling molecules controlling adaptation to hypoxia (HIF‐1α), energy balance (AMPK), mitochondrial biogenesis (PGC‐1α), autophagic/apoptotic processes regulation and proteomic dysregulation were assessed. Responses to acute hypoxia (AH) and chronic hypoxia (CH) in mouse heart proteome were detected by 2‐D DIGE, mass spectrometry and antigen–antibody reactions. Both in AH and CH, the results indicated a deregulation of proteins related to sarcomere stabilization and muscle contraction. Neither in AH nor in CH the HIF‐1α stabilization was observed. In AH, the metabolic adaptation to lack of oxygen was controlled by AMPK activation and sustained by an up‐regulation of adenosylhomocysteinase and acetyl‐CoA synthetase. AH was characterized by the mitophagic protein Bnip 3 increment. PGC‐1α, a master regulator of mitochondrial biogenesis, was down‐regulated. CH was characterized by the up‐regulation of enzymes involved in antioxidant defense, in aldehyde bio‐product detoxification and in misfolded protein degradation. In addition, a general down‐regulation of enzymes controlling anaerobic metabolism was observed. After 10 days of hypoxia, cardioprotective molecules were substantially decreased whereas pro‐apoptotic molecules increased accompained by down‐regulation of specific target proteins.
Feature‐based classification of native and non‐native protein–protein interactions: Comparing supervised and semi‐supervised learning approaches
Authors: Zhao Nan , Pang Bin , Shyu Chi‐Ren , Korkin Dmitry 
Published: September 2011

AbstractStructural knowledge about protein–protein interactions can provide insights to the basic processes underlying cell function. Recent progress in experimental and computational structural biology has led to a rapid growth of experimentally resolved structures and computationally determined near‐native models of protein–protein interactions. However, determining whether a protein–protein interaction is physiological or it is the artifact of an experimental or computational method remains a challenging problem. In this work, we have addressed two related problems. The first problem is distinguishing between the experimentally obtained physiological and crystal‐packing protein–protein interactions. The second problem is concerned with the classification of near‐native and inaccurate docking models. We first defined a universal set of interface features and employed a support vector machines (SVM)‐based approach to classify the interactions for both problems, with the accuracy, precision, and recall for the first problem classifier reaching 93%. To improve the classification, we next developed a semi‐supervised learning approach for the second problem, using transductive SVM (TSVM). We applied both classifiers to a commonly used protein docking benchmark of 124 complexes. We found that while we reached the classification accuracies of 78.9% for the SVM classifier and 80.3% for the TSVM classifier, improving protein‐docking methods by model re‐ranking remains a challenging problem.
Soluble, redox‐active, and blue‐emitting poly(amide‐hydrazide)s and poly(amide‐1,3,4‐oxadiazole)s containing pyrenylamine units
Authors: Kung Yi‐Chun , Hsiao Sheng‐Huei 
Published: September 2011

AbstractTwo new aromatic poly(amide‐hydrazide)s (PAHs)‐bearing electroactive pyrenylamine units in the backbone were prepared from the phosphorylation polycondensation reactions of N,N‐di(4‐carboxyphenyl)‐1‐aminopyrene (1) with p‐aminobenzoyl hydrazide (p‐ABH) and m‐aminobenzoyl hydrazide (m‐ABH), respectively. The PAHs could be further cyclodehydrated into the corresponding poly(amide‐1,3,4‐oxadiazole)s in the range of 300–400 °C in the solid film state. All the hydrazide and oxadiazole polymers were soluble in many polar organic solvents and could afford flexible and strong films via solution casting. The poly(amide‐1,3,4‐oxdiazole)s had high glass‐transition temperatures (294–309 °C) and high thermal stability (10% weight‐loss temperature in excess of 520 °C). The dilute solutions of all the hydrazide and oxadiazole polymers showed strong fluorescence with emission maxima around 457–459 nm in the blue region. Copolymers obtained from the polycondensation of equimolar mixture of diacid 1 and 4,4′‐oxydibenzoic acid with p‐ABH or m‐ABH exhibited a significantly increased fluorescence quantum efficiency in comparison with the homopolymers. Cyclic voltammetry results indicated that all the hydrazide and oxadiazole polymers exhibited an ambipolar (n‐ and p‐doping processes) and electrochromic behavior. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
Theoretical perspective on properties of DNA‐functionalized surfaces
Authors: Singh Abhishek , Eksiri Hamed , Yingling Yaroslava G. 
Published: September 2011

AbstractThe molecular recognition properties of DNA gave rise to many novel materials and applications such as DNA biosensors, DNA‐functionalized colloidal materials, DNA origami and DNA‐based directed surface assembly. The DNA‐functionalized surfaces are used in biosensors and for programmed self‐assembly of biological, organic and inorganic moieties into novel materials. However, surface density, length, and linker design of the surface functionalized DNAs significantly influence the properties of DNA‐driven assemblies and materials. This perspective discusses the understanding of structure and dynamics of DNA immobilized on the surfaces from the theoretical point of view including recent progress in analytical theories, atomistic simulations, and coarse‐grained models. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1563–1568, 2011
Interdisciplinary therapy improves biomarkers profile and lung function in asthmatic obese adolescents
Authors: da Silva Patrícia Leão , de Mello Marco Túlio , Cheik Nadia Carla , Sanches Priscila Lima , Correia Fabíola Alvise , de Piano Aline , Corgosinho Flávia Campos , da Silveira Campos Raquel Munhoz , do Nascimento Claudia M.O. , Oyama Lila M. , Tock Lian , Tufik Sérgio , Dâmaso Ana R. 
Published: September 2011

AbstractBackgroundThe simultaneous rise in the prevalence of asthma and obesity in the world, have demonstrated the importance of the development of treatment strategies. The purpose of this study was to evaluate the short‐ and long‐term results of interdisciplinary therapy on inflammatory biomarkers and lung function in asthmatics obese adolescents.MethodsSeventy‐six post‐pubertal obese adolescents were recruited, including 50 non‐asthmatics [body mass index (BMI), 36 ± 5 kg/m2) and 26 asthmatics (BMI, 39 ± 4 kg/m2). Body composition was measured by plethysmography, and visceral fat was analyzed by ultrasound. Serum levels of adiponectin, leptin, and C‐reactive protein (CRP) were analyzed. Asthma and lung function were evaluated according to the American Thoracic Society criteria. Patients were submitted to 1‐year weight loss interdisciplinary intervention consisting of medical, nutritional, exercise, and psychological therapy.ResultsAfter interdisciplinary intervention, the lung function and pro/anti‐inflammatory adipokines improved significantly in both groups. Most importantly, there was an increase in adiponectin [4 (1.86–12.9) to 5.1 (2.48–16)], a reduction in CRP [2,073 (385–9,174) to 1,538 (205–7,083)] and leptin concentrations [59 (29–69) to 33 (9–49)] in the asthmatics patients. Furthermore, it was observed a reduction in asthma severity after treatment. In addition, Δ adiponectin was an independent factor to improve lung function after therapy in both groups.ConclusionsInterdisciplinary therapy resulted in beneficial changes in inflammatory biomarkers profile and lung function in asthmatic and non‐asthmatic obese adolescents. Additionally, for the first time we showed that change in adiponectin level was an independent predictor to improve lung function in Brazilian obese adolescents. Pediatr Pulmonol. 2012; 47:8–17. © 2010 Wiley Periodicals, Inc.