bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrostatic potential of hydrogenated finite‐length carbon nanotubes under an electric field
Authors: Yamanaka Ayaka , Okada Susumu 
Published: October 2013

AbstractWe study the electronic properties of hydrogenated carbon nanotubes under an electric field based on the density functional theory with effective screening medium method. We find that, screening against the external electric field strongly depends on local atomic arrangement due to the inhomogeneous charge distribution arising from the bond alternation induced by the H‐terminated C atoms at the edge region. Besides the screening arising from the bond alternation, unusual electric field screening occurs at the vicinity of the edge C atomic site in zigzag nanotubes.We also find that the energy gap between the highest occupied and the lowest unoccupied states of armchair and zigzag nanotubes oscillates in triple and double periodicity, respectively, in their units with respect to the length. The electric field induces the charge redistribution in which the charge accumulation and depletion only occur around the H‐terminated C atoms situated near the ends of the nanotubes. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterizations of Al2O3 gate dielectric deposited on n‐GaN by plasma‐assisted atomic layer deposition
Authors: Yoshitsugu Koji , Horita Masahiro , Ishikawa Yasuaki , Uraoka Yukiharu 
Published: October 2013

AbstractThis paper briefly reviews the characterizations of Al2O3 gate dielectric deposited by plasma‐assisted atomic layer deposition (PA‐ALD) on n‐GaN. We report on insulating and physical properties of PA‐ALD Al2O3 film from I‐V characteristics of metal‐insulator‐semiconductor (MIS) diodes and analysis of X‐ray photoelectron spectroscopy (XPS), respectively. Compared to Al2O3 film deposited by thermal ALD method, the PA‐ALD Al2O3 film exhibited higher breakdown field and several orders of magnitude lower leakage current density. Analysis of the current conduction mechanism reveals that the gate leakage current of PA‐ALD Al2O3/n‐GaN MIS diode consisted of Schottky emission (SE) and Fowler‐Nordheim tunneling (FNT). In contrast, it is suggested that trap‐assisted tunneling (TAT) mechanism was dominant in the gate leakage of T‐ALD Al2O3 sample at the middle field range. From the XPS analysis, the band gap of PA‐ALD Al2O3 was estimated about 6.7 eV. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High gain observer for a three‐cell chopper: Design and experimental results
Authors: Ghanes M. , Trabelsi M. , Lin‐Shi X. , Barbot J.‐P. , Retif J.‐M. , Busawon K. 
Published: October 2013

SUMMARYAs capacitor voltages are necessary for the three‐cell DC–DC chopper control, the estimation of such voltages by an observer is attractive solution in terms of cost. However, due to the hybrid behavior of this structure, the capacitor voltages may be partially or even not observable for a given switching configuration. In other words, the observability matrix associated to the capacitor voltages never has a full rank. In order to make the observer conceivable, this paper proposes a new design by establishing sufficient conditions under which the capacitor voltages can be reconstructed within appropriate specific switching sequence and not necessarily instantly. An interconnected high gain observer is then designed for the considered structure. Furthermore, the analysis of convergence is given according to specific switching sequence, and the bounds of the observer tuning parameters are numerically verified. A significant load current benchmark including a three‐cell chopper is used as prototype to show the performance and the effectiveness of the proposed observer. Copyright © 2013 John Wiley & Sons, Ltd.
Singularity‐avoiding swing‐up control for underactuated three‐link gymnast robot using virtual coupling between control torques
Authors: Lai Xuzhi , Zhang Ancai , Wu Min , She Jinhua 
Published: October 2013

SUMMARYAn underactuated three‐link gymnast robot (UTGR) is a simple model of a gymnast on a high bar. The control objective of a UTGR is to swing it up from a point near the straight‐down position and to stabilize it at the straight‐up position. To achieve this, we first divide the motion space into two subspaces, swing‐up area and balancing area, and design a controller for each. The design of a swing‐up control law that ensures that the UTGR enters the balancing area is crucial because the UTGR is subject to a nonholonomic constraint and is highly nonlinear during the swing‐up motion. This study focused on how to design a swing‐up control law that contains no singularities. The key concept is the introduction of a virtual coupling between control torques, which converts the problem of avoiding singularities to one of imposing constraints on the parameters of the control law and properly selecting those parameters. A swing‐up control law thus designed ensures that the UTGR enters the balancing area in a natural stretched‐out posture. This makes it easy to stabilize the UTGR in the balancing area. Copyright © 2013 John Wiley & Sons, Ltd.
Nonlinear control under wave actuator dynamics with time‐ and state‐dependent moving boundary
Authors: Cai Xiushan , Krstic Miroslav 
Published: October 2013

SUMMARYWe consider the stabilization of nonlinear ODE systems with actuator dynamics modeled by a wave PDE whose boundary is moving and is a function of time and of the ODE's state. Such a problem is inspired by applications in oil drilling where the position of the drill bit is a state variable in the ODE modeling the friction‐dominated drill bit dynamics while at the same time being the position of the moving boundary of the wave PDE that models the distributed torsional dynamics of the drillstring. For moving boundaries that depend only on time, we extend the global result recently developed by Bekiaris‐Liberis and Krstic for constant boundaries. For moving boundaries that also depend on the ODE's state, we develop a local result where the initial condition is restricted in such a way that it is ensured that the rate of movement of the boundary (both ‘leftward’ and ‘rightward’) is bounded by unity in closed‐loop. For strict‐feedforward systems under wave actuator dynamics with moving boundaries, the predictor‐based feedback laws are obtained explicitly. The feedback design is illustrated through an example. Copyright © 2013 John Wiley & Sons, Ltd.
Synthesis of satellite footprint patterns from rectangular planar array antenna by using swarm‐based optimization algorithms
Authors: Chatterjee Anirban , Mahanti Gautam Kumar , Ghatak Gourab 
Published: October 2013

SUMMARYA pattern synthesis method based on Firefly Algorithm (FA) and Artificial Bee Colony (ABC) optimization has been presented to generate satellite footprint patterns from a rectangular planar array of isotropic antennas by modifying the amplitude, phase, and the state of the array elements. Three cases comprising three different footprints of rectangular, square, and circular boundary are generated from the same array by using two different swarm‐based optimization algorithms FA and ABC. Both the algorithms, following the proposed procedures are able to generate the three different footprint patterns while maintaining a satisfactory lower peak side lobe level and ripple. A comparative analysis has been carried out between FA, ABC, and Genetic Algorithm (GA) for the presented problem in terms of fitness value for the three different cases. The superiority of FA and ABC over GA has been established in terms of finding better solutions for all the three cases of the proposed problem. Copyright © 2013 John Wiley & Sons, Ltd.
Theorie II. und III. Ordnung – die großen Missverständnisse
Authors: Gensichen Volker , Lumpe Günter 
Published: October 2013

AbstractRäumlich beanspruchte Stäbe und Stabwerke werden in Einklang mit den aktuellen Normen häufig nach Theorie I. oder III. Ordnung nachgewiesen. Es überrascht, dass es weder eine Klassifizierung der verschiedenen Varianten dieser Theorien noch eine Verifikation der Leistungsfähigkeit der hierauf beruhenden Software gibt. Der Beitrag definiert Kategorien der Theorie II. und III. Ordnung. Die grundsätzlichen Defizite sowie die Fehler der Theorien und der Software werden analysiert und an einfachen Beispielen belegt.Theory of 2nd and 3rd order in structural engineering – the big misunderstandings. The application of the theory of elasticity of 2nd order for three‐dimensional lattice framework structures is widely used in structural engineering and modern standards. Nevertheless there is neither a systematic classification of different variants of this theory and the corresponding software nor a verification of their performance. This article defines categories of 2nd and 3rd order. Examples are given to demonstrate the deficits and the errors for the structural design of the theory of 2nd order which can even be found in the most simple systems.
Membrane Biophysics Define Neuron and Astrocyte Progenitors in the Neural Lineage
Authors: Nourse J.L. , Prieto J.L. , Dickson A.R. , Lu J. , Pathak M.M. , Tombola F. , Demetriou M. , Lee A.P. , Flanagan L.A. 
Published: October 2013

Abstract
Neural stem and progenitor cells (NSPCs) are heterogeneous populations of self-renewing stem cells and more committed progenitors that differentiate into neurons, astrocytes, and oligodendrocytes. Accurately identifying and characterizing the different progenitor cells in this lineage has continued to be a challenge for the field. We found previously that populations of NSPCs with more neurogenic progenitors (NPs) can be distinguished from those with more astrogenic progenitors (APs) by their inherent biophysical properties, specifically the electrophysiological property of whole cell membrane capacitance, which we characterized with dielectrophoresis (DEP). Here, we hypothesize that inherent electrophysiological properties are sufficient to define NPs and APs and test this by determining whether isolation of cells solely by these properties specifically separates NPs and APs. We found NPs and APs are enriched in distinct fractions after separation by electrophysiological properties using DEP. A single round of DEP isolation provided greater NP enrichment than sorting with PSA-NCAM, which is considered an NP marker. Additionally, cell surface N-linked glycosylation was found to significantly affect cell fate-specific electrophysiological properties, providing a molecular basis for the cell membrane characteristics. Inherent plasma membrane biophysical properties are thus sufficient to define progenitor cells of differing fate potential in the neural lineage, can be used to specifically isolate these cells, and are linked to patterns of glycosylation on the cell surface. Stem Cells 2014;32:706–716
HIF-Prolyl Hydroxylase 2 Inhibition Enhances the Efficiency of Mesenchymal Stem Cell-Based Therapies for the Treatment of Critical Limb Ischemia
Authors: HoWangYin Kiave-Yune , Loinard Céline , Bakker Wineke , Guérin Coralie L. , Vilar José , D'Audigier Clément , Mauge Laetitia , Bruneval Patrick , Emmerich Joseph , Lévy Bernard I. , Pouysségur Jacques , Smadja David M. , Silvestre Jean-Sébastien 
Published: October 2013

Abstract
Upregulation of hypoxia-inducible transcription factor-1α (HIF-1α), through prolyl-hydroxylase domain protein (PHD) inhibition, can be thought of as a master switch that coordinates the expression of a wide repertoire of genes involved in regulating vascular growth and remodeling. We aimed to unravel the effect of specific PHD2 isoform silencing in cell-based strategies designed to promote therapeutic revascularization in patients with critical limb ischemia (CLI). PHD2 mRNA levels were upregulated whereas that of HIF-1α were downregulated in blood cells from patients with CLI. We therefore assessed the putative beneficial effects of PHD2 silencing on human bone marrow-derived mesenchymal stem cells (hBM-MSC)-based therapy. PHD2 silencing enhanced hBM-MSC therapeutic effect in an experimental model of CLI in Nude mice, through an upregulation of HIF-1α and its target gene, VEGF-A. In addition, PHD2-transfected hBM-MSC displayed higher protection against apoptosis in vitro and increased rate of survival in the ischemic tissue, as assessed by Fluorescence Molecular Tomography. Cotransfection with HIF-1α or VEGF-A short interfering RNAs fully abrogated the beneficial effect of PHD2 silencing on the proangiogenic capacity of hBM-MSC. We finally investigated the effect of PHD2 inhibition on the revascularization potential of ischemic targeted tissues in the diabetic pathological context. Inhibition of PHD-2 with shRNAs increased postischemic neovascularization in diabetic mice with CLI. This increase was associated with an upregulation of proangiogenic and proarteriogenic factors and was blunted by concomitant silencing of HIF-1α. In conclusion, silencing of PHD2, by the transient upregulation of HIF-1α and its target gene VEGF-A, might improve the efficiency of hBM-MSC-based therapies. Stem Cells 2014;32:231–243
The Toll-like Receptor 3 Ligand, Poly(I:C), Improves Immunosuppressive Function and Therapeutic Effect of Mesenchymal Stem Cells on Sepsis via Inhibiting MiR-143
Authors: Zhao Xiaoyin , Liu Dan , Gong Wei , Zhao Guangfeng , Liu Liu , Yang Liu , Hou Yayi 
Published: October 2013

AbstractMesenchymal stem cells (MSCs) are attractive candidates for clinical therapeutic applications. Recent studies indicate MSCs express active Toll-like receptors (TLRs), but their effect on MSCs and the underlying mechanisms remain unclear. In this study, we found that, after treating human umbilical cord MSCs with various TLR ligands, only TLR3 ligand, poly(I:C), could significantly increase the expression of cyclooxygenase-2 (COX-2). Furthermore, poly(I:C) could enhance MSCs’ anti-inflammatory effect on macrophages. Next, we focused on the regulatory roles of microRNAs (miRNAs) in the process of poly(I:C) activating MSCs. Our experiments indicated that miR-143 expression was significantly decreased in MSCs with poly(I:C) treatment, and the expression level of miR-143 could regulate the effect of poly(I:C) on MSCs’ immunosuppressive function. Subsequent results showed that the reporter genes with putative miR-143 binding sites from the transforming growth factor-β-activated kinase-1 (TAK1) and COX-2 3′ untranslated regions were downregulated in the presence of miR-143. In addition, mRNA and protein expression of TAK1 and COX-2 in MSCs was also downregulated with miR-143 overexpression, suggesting that TAK1 and COX-2 are target genes of miR-143 in MSCs. Consistent with miR-143 overexpression, TAK1 interference also attenuated MSCs’ immunosuppressive function enhanced by poly(I:C). Additionally, it was shown that TLR3-activated MSCs could improve survival in cecal ligation and puncture (CLP)-induced sepsis, while miR-143 overexpression reduced the effectiveness of this therapy. These results proved that poly(I:C) improved the immunosuppressive abilities of MSCs, revealed the regulatory role of miRNAs in the process, and may provide an opportunity for potential novel therapies for sepsis. Stem Cells 2014;32:521–533
Forecasting propagation and evolution of CMEs in an operational setting: What has been learned
Authors: Zheng Yihua , Macneice Peter , Odstrcil Dusan , Mays M. L. , Rastaetter Lutz , Pulkkinen Antti , Taktakishvili Aleksandre , Hesse Michael , Masha Kuznetsova M. , Lee Hyesook , Chulaki Anna 
Published: October 2013

AbstractOne of the major types of solar eruption, coronal mass ejections (CMEs) not only impact space weather, but also can have significant societal consequences. CMEs cause intense geomagnetic storms and drive fast mode shocks that accelerate charged particles, potentially resulting in enhanced radiation levels both in ions and electrons. Human and technological assets in space can be endangered as a result. CMEs are also the major contributor to generating large amplitude Geomagnetically Induced Currents (GICs), which are a source of concern for power grid safety. Due to their space weather significance, forecasting the evolution and impacts of CMEs has become a much desired capability for space weather operations worldwide. Based on our operational experience at Space Weather Research Center at NASA Goddard Space Flight Center (http://swrc.gsfc.nasa.gov), we present here some of the insights gained about accurately predicting CME impacts, particularly in relation to space weather operations. These include: 1. The need to maximize information to get an accurate handle of three‐dimensional (3‐D) CME kinetic parameters and therefore improve CME forecast; 2. The potential use of CME simulation results for qualitative prediction of regions of space where solar energetic particles (SEPs) may be found; 3. The need to include all CMEs occurring within a ~24 h period for a better representation of the CME interactions; 4. Various other important parameters in forecasting CME evolution in interplanetary space, with special emphasis on the CME propagation direction. It is noted that a future direction for our CME forecasting is to employ the ensemble modeling approach.
Synextensional magmatism leading to crustal flow in the Albion–Raft River–Grouse Creek metamorphic core complex, northeastern Basin and Range
Authors: Konstantinou Alexandros , Strickland Ariel , Miller Elizabeth , Vervoort Jeffrey , Fisher Christopher M. , Wooden Joseph , Valley John 
Published: October 2013

AbstractThis study addresses the origin of granitic magmas in the Albion–Raft River–Grouse Creek (ARG) metamorphic core complex and environs and how these inform us about the deep crustal processes leading to crustal flow and the formation of the ARG. SHRIMP‐RG U‐Pb zircon ages, whole‐rock geochemical data (major and trace element data, as well as Sr and Nd isotopes), and zircon geochemistry (in situ O‐isotope, Hf‐isotope, and trace element compositions) from Eocene to Oligocene magmas now exposed at three structural levels of the ARG show that the 41–32 Ma Emigrant Pass and the 32–25 Ma Cassia plutonic complexes have a common origin, sharing a deep crustal “hot zone” that remained above solidus temperatures for at least 16 Myr. This magmatism is part of the protracted magmatism that swept southward across the western U.S. between ∼42 and 21 Ma, inferred to be the result of foundering of the shallow Farallon slab. Isotopic modeling of geochemical data from these magmas suggests that between 41 and 32 Ma, the influx of mantle‐derived basalt into the lower crust triggered large‐scale hybrid magmatism generating calc‐alkaline magmas that erupted and intruded the upper crust and significantly weakened the lower and middle crust. Between 32 and 25 Ma, this “hot zone” incorporated large amounts of continental crustal melts, resulting in greater mobility of the lower and middle crust, driving middle crustal flow and the formation of granitic plutons that rose to shallower levels of the crust forming the granite‐cored gneiss domes of the ARG.
Structural health and prognostics management for the enhancement of offshore wind turbine operations and maintenance strategies
Authors: Griffith D. Todd , Yoder Nathanael C. , Resor Brian , White Jonathan , Paquette Joshua 
Published: October 2013

ABSTRACTOffshore wind turbines are an attractive source for clean and renewable energy for reasons including their proximity to population centers and higher capacity factors. One obstacle to the more widespread installation of offshore wind turbines in the USA, however, is that recent projections of offshore operations and maintenance costs vary from two to five times the land‐based costs. One way in which these costs could be reduced is through use of a structural health and prognostics management (SHPM) system as part of a condition‐based maintenance paradigm with smart loads management. This paper contributes to the development of such strategies by developing an initial roadmap for SHPM, with application to the blades. One of the key elements of the approach is a multiscale simulation approach developed to identify how the underlying physics of the system are affected by the presence of damage and how these changes manifest themselves in the operational response of a full turbine. A case study of a trailing edge disbond is analysed to demonstrate the multiscale sensitivity of damage approach and to show the potential life extension and increased energy capture that can be achieved using simple changes in the overall turbine control and loads management strategy. The integration of health monitoring information, economic considerations such as repair costs versus state of health, and a smart loads management methodology provides an initial roadmap for reducing operations and maintenance costs for offshore wind farms while increasing turbine availability and overall profit. Copyright © 2013 John Wiley & Sons, Ltd.
Counterexamples in the theory of coerciveness for linear elliptic systems related to generalizations of Korn's second inequality
Authors: Neff P. , Pompe W. 
Published: October 2013

AbstractWe show that the following generalized version of Korn's second inequality with nonconstant measurable matrix valued coefficients P: Ω ⊂ ℝ3 → ℝ3× 3

is in general false, even if P ∈ SO(3), while the Legendre‐Hadamard condition and ellipticity on ℂn for the quadratic form |Du P+(DuP)T|2 is satisfied. Thus Gårding's inequality may be violated for formally positive quadratic forms.
Axisymmetric contact problems of the theory of elasticity for inhomogeneous layers
Authors: Vasiliev A. , Volkov S. , Aizikovich S. , Jeng Y.‐R. 
Published: October 2013

AbstractAn approach for constructing semi‐analytical solutions in contact problems of the theory of elasticity for inhomogeneous layers is developed. The approach is efficient for the layer of arbitrary thickness which is either continuously inhomogeneous (functionally graded) or piecewise homogeneous (i.e. presented as a set of homogeneous layers with different elastic properties). The foundation is also assumed to be elastic, but much stiffer than the layer. The loads considered address the case of axisymmetric contact problems under torsion and indentation of a rigid circular punch with the flat base. The technique based on integral transforms is used to reduce the problems to the integral equations. Special approximations for the kernel transforms are used to obtain analytical solutions of the integral equations. The main results include computations of the profiles of contact stresses under the punch and the dependences of displacements with depth for different types of variation of elastic properties in the layer. The results are also compared with those obtained by other methods.