bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical subtypes of Parkinson's disease
Authors: van Rooden Stephanie M. , Colas Fabrice , Martínez‐Martín Pablo , Visser Martine , Verbaan Dagmar , Marinus Johan , Chaudhuri Ray K. , Kok Joost N. , van Hilten Jacobus J. 
Published: November 2010

AbstractThe clinical heterogeneity of Parkinson's disease (PD) may point at the existence of subtypes. Because subtypes likely reflect distinct underlying etiologies, their identification may facilitate future genetic and pharmacotherapeutic studies. Aim of this study was to identify subtypes by a data‐driven approach applied to a broad spectrum of motor and nonmotor features of PD. Data of motor and nonmotor PD symptoms were collected in 802 patients in two different European prevalent cohorts. A model‐based cluster analysis was conducted on baseline data of 344 patients of a Dutch cohort (PROPARK). Reproducibility of these results was tested in data of the second annual assessment of the same cohort and validated in an independent Spanish cohort (ELEP) of 357 patients. The subtypes were subsequently characterized on clinical and demographic variables. Four similar PD subtypes were identified in two different populations and are largely characterized by differences in the severity of nondopaminergic features and motor complications: Subtype 1 was mildly affected in all domains, Subtype 2 was predominantly characterized by severe motor complications, Subtype 3 was affected mainly on nondopaminergic domains without prominent motor complications, while Subtype 4 was severely affected on all domains. The subtypes had largely similar mean disease durations (nonsignificant differences between three clusters) but showed considerable differences with respect to their association with demographic and clinical variables. In prevalent disease, PD subtypes are largely characterized by the severity of nondopaminergic features and motor complications and likely reflect complex interactions between disease mechanisms, treatment, aging, and gender. © 2010 Movement Disorder Society.
Petri Nets – A Mathematical Formalism to Analyze Chemical Reaction Networks
Authors: Koch Ina 
Published: November 2010

AbstractIn this review we introduce and discuss Petri nets – a mathematical formalism to describe and analyze chemical reaction networks. Petri nets were developed to describe concurrency in general systems. We find most applications to technical and financial systems, but since about twenty years also in systems biology to model biochemical systems. This review aims to give a short informal introduction to the basic formalism illustrated by a chemical example, and to discuss possible applications to the analysis of chemical reaction networks, including cheminformatics. We give a short overview about qualitative as well as quantitative modeling Petri net techniques useful in systems biology, summarizing the state‐of‐the‐art in that field and providing the main literature references. Finally, we discuss advantages and limitations of Petri nets and give an outlook to further development.
Specific absorption rate reduction in parallel transmission by k‐space adaptive radiofrequency pulse design
Authors: Homann Hanno , Graesslin Ingmar , Nehrke Kay , Findeklee Christian , Dössel Olaf , Börnert Peter 
Published: November 2010

AbstractThe specific absorption rate (SAR) is an important safety criterion, limiting many MR protocols with respect to the achievable contrast and scan duration. Parallel transmission enables control of the radiofrequency field in space and time and hence allows for SAR management. However, a trade‐off exists between radiofrequency pulse performance and SAR reduction. To overcome this problem, in this work, parallel transmit radiofrequency pulses are adapted to the position in sampling k‐space. In the central k‐space, highly homogeneous but SAR‐intensive radiofrequency shim settings are used to achieve optimal performance and contrast. In the outer k‐space, the homogeneity requirement is relaxed to reduce the average SAR of the scan. The approach was experimentally verified on phantoms and volunteers using field echo and spin echo sequences. A reduction of the SAR by 25–50% was achieved without compromising image quality. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Two‐point dixon method with flexible echo times
Authors: Berglund Johan , Ahlström Håkan , Johansson Lars , Kullberg Joel 
Published: November 2010

AbstractThe two‐point Dixon method is a proton chemical shift imaging technique that produces separated water‐only and fat‐only images from a dual‐echo acquisition. It is shown how this can be achieved without the usual constraints on the echo times. A signal model considering spectral broadening of the fat peak is proposed for improved water/fat separation. Phase errors, mostly due to static field inhomogeneity, must be removed prior to least‐squares estimation of water and fat. To resolve ambiguity of the phase errors, a corresponding global optimization problem is formulated and solved using a message‐passing algorithm. It is shown that the noise in the water and fat estimates matches the Cramér‐Rao bounds, and feasibility is demonstrated for in vivo abdominal breath‐hold imaging. The water‐only images were found to offer superior fat suppression compared with conventional spectrally fat suppressed images. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Anisotropic anomalous diffusion assessed in the human brain by scalar invariant indices
Authors: De Santis S. , Gabrielli A. , Bozzali M. , Maraviglia B. , Macaluso E. , Capuani S. 
Published: November 2010

AbstractA new method to investigate anomalous diffusion in human brain, inspired by the stretched‐exponential model proposed by Hall and Barrick, is proposed here, together with a discussion about its potential application to cerebral white matter characterization. Aim of the work was to show the ability of anomalous diffusion indices to characterize white matter structures, whose complexity is only partially accounted by diffusion tensor imaging indices. MR signal was expressed as a stretched‐exponential only along the principal axes of diffusion; whereas, in a generic direction, it was modeled as a combination of three stretched‐exponentials. Indices to quantify the tissue anomalous diffusion and its anisotropy, independently of the experiment reference frame, were derived. Experimental results, obtained on 10 healthy subjects at 3T, show that the new parameters are highly correlated to intrinsic local geometry when compared with Hall and Barrick indices. Moreover, they offer a different contrast in white matter regions when compared with diffusion tensor imaging. Specifically, the new indices show a higher capability to discriminate among areas of the corpus callosum associated to different distribution in axonal densities, thus offering a new potential tool to detect more specific patterns of brain abnormalities than diffusion tensor imaging in the presence of neurological and psychiatric disorders. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Detecting response of rat C6 glioma tumors to radiotherapy using hyperpolarized [1‐13C]pyruvate and 13C magnetic resonance spectroscopic imaging
Authors: Day Sam E. , Kettunen Mikko I. , Cherukuri Murali Krishna , Mitchell James B. , Lizak Martin J. , Morris H. Douglas , Matsumoto Shingo , Koretsky Alan P. , Brindle Kevin M. 
Published: November 2010

AbstractWe show here that hyperpolarized [1‐13C]pyruvate can be used to detect treatment response in a glioma tumor model; a tumor type where detection of response with 18fluoro‐2‐deoxyglucose, using positron emission tomography, is limited by the high background signals from normal brain tissue. 13C chemical shift images acquired following intravenous injection of hyperpolarized [1‐13C]pyruvate into rats with implanted C6 gliomas showed significant labeling of lactate within the tumors but comparatively low levels in surrounding brain.Labeled pyruvate was observed at high levels in blood vessels above the brain and from other major vessels elsewhere but was detected at only low levels in tumor and brain.The ratio of hyperpolarized 13C label in tumor lactate compared to the maximum pyruvate signal in the blood vessels was decreased from 0.38 ± 0.16 to 0.23 ± 0.13, (a reduction of 34%) by 72 h following whole brain irradiation with 15 Gy. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Hindlimb skeletal muscle function in myostatin‐deficient mice
Authors: Gentry Bettina A. , Ferreira J. Andries , Phillips Charlotte L. , Brown Marybeth 
Published: November 2010

AbstractAbsence of functional myostatin (MSTN) during fetal development results in adult skeletal muscle hypertrophy and hyperplasia. To more fully characterize MSTN loss in hindlimb muscles, the morphology and contractile function of the soleus, plantaris, gastrocnemius, tibialis anterior, and quadriceps muscles in male and female null (Mstn−/−), heterozygous (Mstn+/−), and wild‐type (Mstn+/+) mice were investigated. Muscle weights of Mstn−/− mice were greater than those of Mstn+/+ and Mstn+/− mice. Fiber cross‐sectional area (CSA) was increased in female Mstn−/− soleus and gastrocnemius muscles and in the quadriceps of male Mstn−/− mice; peak tetanic force in Mstn−/− mice did not parallel the increased muscle weight or CSA. Male Mstn−/− muscle exhibited moderate degeneration. Visible pathology in male mice and decreased contractile strength relative to increased muscle weight suggest MSTN loss results in muscle impairment, which is dose‐, sex‐, and muscle‐dependent. Muscle Nerve, 2011
Hereditary inclusion‐body myopathy associated with cardiomyopathy: Report of two siblings
Authors: Chai Yaohui , Bertorini Tulio E. , McGrew Frank A. 
Published: November 2010

AbstractHereditary inclusion‐body myopathy (HIBM) or distal myopathy with rimmed vacuoles (DMRV) is an autosomal recessive disorder characterized by preferential involvement of distal muscles in the lower extremities, especially the anterior compartment of the legs, with relative preservation of the quadriceps.This is referred to as quadriceps‐sparing myopathy. Previous reports have revealed exclusive involvement in skeletal muscles. Herein we describe two siblings with typical HIBM/DMRV. The patients developed exertional dyspnea 20–26 years after disease onset. Echocardiogram revealed a cardiomyopathy in both patients. This is the first report of the association between HIBM/DMRV and cardiomyopathy. Muscle Nerve, 2011
Vascular endothelial growth factor helps differentiate neuropathies in rare plasma cell dyscrasias
Authors: Briani Chiara , Fabrizi Gian Maria , Ruggero Susanna , Torre Chiara Dalla , Ferrarini Moreno , Campagnolo Marta , Cavallaro Tiziana , Ferrari Sergio , Scarlato Marina , Taioli Federica , Adami Fausto 
Published: November 2010

AbstractPOEMS syndrome and amyloidosis are rare plasma cell diseases that share common features, including polyneuropathy. The aim of this study was to investigate serum vascular endothelial growth factor (sVEGF) in patients with amyloidosis and to evaluate changes in response to treatment. Twenty‐five patients [17 primary light‐chain amyloidosis (AL‐A), 7 transthyretin amyloidosis (TTR‐A), 1 senile wild‐type TTR‐A] were studied. sVEGF was analyzed by ELISA. Sera from 8 myeloma and 7 POEMS patients were also evaluated. The median sVEGF level was 420 pg/ml in AL‐A and 179 pg/ml in TTR‐A patients; this was significantly lower than in POEMS syndrome (median 2580 pg/ml, P = 0.0002 and 0.001, respectively). sVEGF of AL‐A patients showed no changes in response to treatment. sVEGF was not increased in amyloid patients regardless of neuropathy, and did not mirror the course of the disease. sVEGF should be tested in patients with overlapping and atypical clinical features. Muscle Nerve, 2011
The MG‐QOL15 for following the health‐related quality of life of patients with myasthenia gravis
Authors: Burns Ted M , Grouse C.K , Wolfe Gil I , Conaway Mark R , Sanders Donald B 
Published: November 2010

AbstractThe MG‐QOL15 is helpful in informing the clinician about the patient's perception of the extent of and dissatisfaction with myasthenia gravis (MG)‐related dysfunction. The aims of this study were to determine the usefulness of the MG‐QOL15 for following individuals with MG and to guide clinical researchers who plan to use the MG‐QOL15. We assessed sensitivity and specificity for detecting clinical change and evaluated test–retest reliability. Sensitivities and specificities of various cut‐points of change in scores are presented. Also presented are means and standard deviations of MG‐QOL15 scores for all patients and for subgroups of patients. The test–retest reliability coefficient was 98.6%. The MG‐QOL15 has an acceptable longitudinal construct validity. We consider this instrument to be most useful for informing the clinician about the patient's perception and tolerance of MG‐related dysfunction. More objective measures, such as the MG Composite, should also be used to follow disease severity. Muscle Nerve, 2011
Comparison of beneficial effects of undifferentiated cultured bone marrow stromal cells and omental adipose‐derived nucleated cell fractions on sciatic nerve regeneration
Authors: Mohammadi Rahim , Azizi Saeed , Delirezh Nowruz , Hobbenaghi Rahim , Amini Keyvan 
Published: November 2010

AbstractAdipose tissue is a good source for isolation of cells with stem‐cell–like properties. The effects of undifferentiated cultured bone marrow stromal cells (BMSCs) and omental adipose‐derived nucleated cells (OADNCs) on peripheral nerve regeneration were compared in a rat nerve regeneration model. A 10‐mm sciatic nerve defect was bridged using a vein graft. In one group, the vein was filled with BMSCs and in the other group with OADNCs. Functional study, morphometric indices, and immunohistochemistry indicated there was no significant difference (P > 0.05) between groups in recovery of regenerated axons at 4, 8, and 12 weeks after surgery. OADNCs enhanced regeneration similar to undifferentiated BMSCs. These observations suggest OADNCs represent an effective and cost‐saving cell population due to the shortened time interval from tissue collection to cell injection as well as procedural simplicity. This approach is clinically translatable toward new methods for enhanced peripheral nerve repair without the limitations of BMSC. Muscle Nerve, 2011
Analysis of Guided Lamb Wave Propagation (GW) in Honeycomb Sandwich Panels
Authors: Hosseini Seyed Mohammad Hossein , Gabbert Ulrich 
Published: November 2010

AbstractThe paper aims to introduce the guided lamb wave propagation (GW) in a honeycomb sandwich panels to be used in the health monitoring applications. Honeycomb sandwich panels are well‐known as lightweight structures with a good stiffness behavior and a wide range of applications in different industries. Due to the complex geometry and complicated boundary conditions in such a structure, the development of analytical solutions for describing the wave propagation and the interaction of waves with damages is hardly possible. Therefore dimensional finite element simulations have been used to model GW for different frequency ranges and different sandwich panels with different geometrical properties. The waves, which are highly dispersive, have been excited by thin piezoelectric patches attached to the surface of the structure. In the first step, the honeycomb panel has been simplified as an orthotropic layered continuum medium. The required material data have been calculated by applying a numerical homogenization method for the honeycomb core layer. The wave propagation has been compared in the homogenized model with the real geometry of a honeycomb sandwich panel. Such calculations of high frequency ultrasonic waves are costly, both in creating a proper finite element model as well as in the required calculation time. In this paper the influence of changes in the geometry of the sandwich panel on the wave propagation is presented. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of Wave‐Based SHM Systems Using the Spectral Element Method
Authors: Schulte R. T. , Fritzen C.‐P. 
Published: November 2010

AbstractIn nondestructive testing, the use of ultrasonic elastic waves has proven as one of the most successful techniques to detect structural damage such as cracks or delaminations. Especially, Structural Health Monitoring (SHM) is characterized by permanently installed actuators and sensors. As the capability of most approaches strongly depends on adequate choice of parameters like excitation signals and actuator/sensor positions, there is a growing interest in efficient and accurate simulation tools to be able to perform virtual SHM‐system design. With respect to high frequency excitation an efficient simulation method is required. This contribution presents the formulation of spectral elements for flat shells based on the first order shear deformation theory (FSDT). A load‐dependent geometrical stiffness matrix is included to take static preloads into account. The spectral element method generates an optimally concentrated mass matrix leading to significant savings of memory and to a reduction of complexity of the time integration algorithm. Dispersion curves of the FSDT are compared to those of 3D elasticity theory to determine the useful application range. Numerical and experimental examples for the propagation of waves including the influence of static prestress and the interaction with delamination are presented. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High order asymptotic approach to the evaluation of near field, radiated by ultrasonic transducer to the layered elastic plates
Authors: Zakharov Dmitry 
Published: November 2010

AbstractIt is well known that one of the most time consuming problem in non‐destructive evaluation (NDE) is the near‐field modeling. In our approach the near field radiated by an ultrasonic transducer (UT) to the first Fresnel zone is approximated in the frequency domain by a closed form asymptotic solution based on the 3‐D generalized orthogonality conditions of Lamb waves and on the stationary phase method. As shown, these asymptotics permit us to elucidate the physics and to work out a numerical algorithm which is about 104 times faster than any direct way of computation. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Experimental/Numerical Investigation on Drag Reduction by Dimples
Authors: Lienhart Hermann , Breuer Michael , Köksoy Cagatay 
Published: November 2010

AbstractThe paper is concerned with experimental and numerical investigations of the turbulent flow over dimpled surfaces. Shallow dimples distributed regularly over the wall of a plane channel with large aspect ratio are used to study their effect on the skin‐friction drag. The resulting pressure drop in the channel was measured for smooth and dimpled walls. In addition to these investigations on internal flows, an external flow study was performed and boundary‐layer profiles were measured using a Pitot‐tube rake. Complementary to the measurements, direct numerical simulations for the internal flow configuration with and without dimples were carried out for two different grid resolutions and analyzed in detail. The objective was to clarify whether or not dimples cause reduction of the skin‐friction drag. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of rotation vectors from multi‐point data and practical applications
Authors: Mladenova Clementina 
Published: November 2010

AbstractThe present work aims to present a different set of parameters for Euclidean motions which have a definite physical interpretation. The orientation here is obtained via vector‐parameters which are elements of a Lie group with a nice and clear composition law. The method is quite convenient for describing of rigid body and manipulators motions such as scene and image processing and recognition. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modular Modelling and Control of Redundant Robots
Authors: Oberhuber Bernhard , Gattringer Hubert , Hofer Andreas , Bremer Hartmut 
Published: November 2010

AbstractWhen robots should work in interaction with humans, the robots have to comply. Not only the human is acting in the environment of the robot, the environment itself is vaguely defined. A modular articulated redundant robot with 7 joints is considered. The joints are actuated by brushless DC motors combined with Harmonic Drive gears. The development of the differential equations of the robot is done with the projection equation in subsystem description. The resulting dynamic behavior is used for feedback control design. To obtain the robust numerical inverse kinematics, singular value avoidance and additional conditions have to be added like joint damping and the limits of working space. Three different impedance controllers for human robot interaction are considered. The first active one uses a 6 axes force/torque sensor to regulate the compliance in joint space. The second one performs the same task in Cartesian space with respect to the end‐effector. The passive approach does not require additional sensors at all and also includes the null‐space of the redundant structure in addition to Cartesian end‐effector movements. This scheme is based solely on the feedback of joint positions and their time derivatives. Measurements and simulation results are presented. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A flexible approach to the simulation of hybrid multibody systems
Authors: Sänger Nicolas , Betsch Peter 
Published: November 2010

AbstractThe present works deals with the incorporation of both flexible beam and shell structures into the realm of flexible multibody dynamics. Geometrically exact beam formulations based on classical Simo‐Reissner kinematics are suitable for modelling beam‐type flexible components in the context of finite‐deformation multibody dynamics. So geometrically exact shell formulations are based on Reissner‐Mindlin kinematics.In [2], a flexible framework for dealing with flexible structural elements in a multibody context is described. A specific isoparametric finite element discretization of a shell formulation leads to semi‐discrete equations of motions assuming the form of differential‐algebraic equations (DAEs). A compatible isoparametric formulation of beams has already been developed in [1].The uniform DAE framework makes possible the incorporation of alternative finite element formulations. In addition to that, various time‐stepping schemes such as energy‐momentum methods or variational integrators can be applied. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An implicit approach to predict the dynamics of granular media
Authors: Samiei Kasra , Peters Bernhard , Bolten Matthias , Frommer Andreas 
Published: November 2010

AbstractThe objective of this study is to present an implicit method to predict the dynamics of granular particles. In the proposed methodology, the dynamics equation of colliding particles are solved implicitly which means the positions of particles at the next time step are also used to compute the next state of the particles. This is in contrast with the explicit approach where only known i.e. past information is used to calculate the new positions. The method is tested in a simple setting where a spherical particle is in continuous movement between two boundary walls. The results show that considerably larger time steps are enabled with the implicit method compared to the explicit method. Future work will compare the overall efficiency of the implicit and explicit methods in more detail. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)