bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controllable centrifugal pendulum
Authors: Ineichen Laurent 
Published: November 2010

AbstractThe combustion engine produces huge rotational periodic vibrations that could affect the acoustic comfort of the vehicle. An isolating device is placed after the engine and filters the oscillations in order to deliver a clean averaged torque to the rest of the drive train. The centrifugal pendulum is widely used even though its passive version can quench only one order of vibration.We propose in [3] a design allowing to control the tuning of the pendulum. An actuator delivers an additional force that completes the centrifugal force. This is equivalent to changing the stiffness of a classical vibration absorber. In this paper, we apply to the stiffness an optimal feedback control on a neighbouring extremal path as defined in [1]. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Group‐Theoretic Approach to Parameter Identifiability of PDE Systems
Authors: Rieger Karl , Schlacher Kurt 
Published: November 2010

AbstractThe contribution is devoted to the parameter identifiability problem of (nonlinear) PDE systems. Especially, we discuss the (local) identifiability of parameters along a trajectory. The analysis relies on a coordinate‐free formulation for systems, including boundary conditions, and we motivate an approach by (Lie) transformation groups, whose success for PDE systems depends on a consequent extent to the accompanying boundary conditions. The (non‐)identifiability of parameters is related to the (non‐)existence of group generators, wherewith (local) conditions can be derived. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computational homogenization for heterogeneous cohesive layers incorporating size effects
Authors: Hirschberger C. B. 
Published: November 2010

AbstractA numerical framework is presented for the multiscale modelling of material layers that possess a both heterogeneous and microstructured mesostructure. The material layer is represented as a cohesive interface on the macro level, while on the meso level micromorphic representative volume elements are used. A computational homogenization approach for the cohesive material layers has been proposed to solve this nonlinear multiscale problem numerically. The present framework is particularly well suited for the modelling of damage and failure, as the micromorphic RVE is well known for its regularizing character. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling crack micro‐branching using finite elements with embedded strong discontinuities
Authors: Raina Arun , Linder Christian 
Published: November 2010

AbstractThe emphasis of this work lies in the development of a numerical method which is capable of representing the complex physical phenomena arising in the case of crack branching in brittle materials. In particular, the formation of crack micro‐branches needs to be accounted for when it comes to the prediction of the propagation pattern of crack macro‐branches which will ultimately lead to the failure of the material. This is achieved by numerically modeling the failure zones within the individual finite elements based on the concept of the embedded finite element method, where all the information with regard to the geometry of the failure zone is stored locally on the element level leading to a very efficient methodology capable of discretely resolving the failure zone. The main feature of the current work is the redundancy of the branching criterion based on crack tip velocity and that both, micro‐ as well as macro‐branches can be modeled. Whether a micro‐crack develops into a macro‐crack solely depends on the local state of the material as it is outlined based on the application of the proposed numerical scheme on a rectangular block with a pre‐existing notch set under tension. A comparison of the oscillatory behavior of the obtained crack tip velocity every time a micro‐crack develops with experimental results from the literature is provided. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of material failure by the discrete element method
Authors: Schneider Benjamin , Bischoff Manfred , Ramm Ekkehard 
Published: November 2010

AbstractIn this paper a two‐dimensional discrete element method with rigid, polygonal particles is used to model material failure of granular as well as quasi‐brittle materials. Different models for soft contact as well as cohesion between the particles are presented. The capabilities of the method are demonstrated simulating simplistic granular model materials as well as complex concrete specimens with an artificial microstructure. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Highly efficient purification of protein complexes from mammalian cells using a novel streptavidin‐binding peptide and hexahistidine tandem tag system: Application to Bruton's tyrosine kinase
Authors: Li Yifeng , Franklin Sarah , Zhang Michael J. , Vondriska Thomas M. 
Published: November 2010

AbstractTandem affinity purification (TAP) is a generic approach for the purification of protein complexes. The key advantage of TAP is the engineering of dual affinity tags that, when attached to the protein of interest, allow purification of the target protein along with its binding partners through two consecutive purification steps. The tandem tag used in the original method consists of two IgG‐binding units of protein A from Staphylococcus aureus (ProtA) and the calmodulin‐binding peptide (CBP), and it allows for recovery of 20–30% of the bait protein in yeast. When applied to higher eukaryotes, however, this classical TAP tag suffers from low yields. To improve protein recovery in systems other than yeast, we describe herein the development of a three‐tag system comprised of CBP, streptavidin‐binding peptide (SBP) and hexa‐histidine. We illustrate the application of this approach for the purification of human Bruton's tyrosine kinase (Btk), which results in highly efficient binding and elution of bait protein in both purification steps (>50% recovery). Combined with mass spectrometry for protein identification, this TAP strategy facilitated the first nonbiased analysis of Btk interacting proteins. The high efficiency of the SBP‐His6 purification allows for efficient recovery of protein complexes formed with a target protein of interest from a small amount of starting material, enhancing the ability to detect low abundance and transient interactions in eukaryotic cell systems.
Subunit arrangement in the dodecameric chloroplast small heat shock protein Hsp21
Authors: Lambert Wietske , Koeck Philip J.B. , Ahrman Emma , Purhonen Pasi , Cheng Kimberley , Elmlund Dominika , Hebert Hans , Emanuelsson Cecilia 
Published: November 2010

AbstractUnfolding proteins are prevented from irreversible aggregation by small heat shock proteins (sHsps) through interactions that depend on a dynamic equilibrium between sHsp subunits and sHsp oligomers. A chloroplast‐localized sHsp, Hsp21, provides protection to client proteins to increase plant stress resistance. Structural information is lacking concerning the oligomeric conformation of this sHsp. We here present a structure model of Arabidopsis thaliana Hsp21, obtained by homology modeling, single‐particle electron microscopy, and lysine‐specific chemical crosslinking. The model shows that the Hsp21 subunits are arranged in two hexameric discs, similar to a cytosolic plant sHsp homolog that has been structurally determined after crystallization. However, the two hexameric discs of Hsp21 are rotated by 25° in relation to each other, suggesting a role for global dynamics in dodecamer function.
Antifatigue activity of the liposoluble fraction from Acanthopanax senticosus
Authors: Huang Lin‐Zhang , Huang Bao‐Kang , Liang Jie , Zheng Cheng‐Jian , Han Ting , Zhang Qiao‐Yan , Qin Lu‐Ping 
Published: November 2010

AbstractThe crude extract of Acanthopanax senticosus (AS) has been used extensively in Russia, China, Korea and Japan as an adaptogenic agent to fight against stress and fatigue. However, whether the liposoluble fraction possesses antifatigue activity or not is still unclear. A liposoluble fraction was administered orally to mice for 9 days. The swimming time to exhaustion was longer in the treatment groups (22.2 ± 3.3, 25.5 ± 4.8 min) than in the control group (13.7 ± 1.2 min, p < 0.05). The plasma TG (triglyceride) and BUN (blood urea nitrogen) levels in the high dose (500 mg/kg) groups were decreased significantly compared with the control group. Plasma lactate dehydrogenase (LDH) was lower in the treatment groups than in the control group. Chemical analysis from GC/MS revealed that the main components of the liposoluble fraction of AS were saturated fatty acid (12.98%), unsaturated fatty acid (33.13%), unsaturated alcohol (27.46%) and diolefine (15.76%). In conclusion, the liposoluble fraction enhanced the forced swimming capacity of mice by decreasing muscle damage, effectively preventing the increase in BUN concentration and increasing fat utilization. It is proposed that the antioxidant effect may be one of the antifatigue mechanisms of the liposoluble fraction of AS. Copyright © 2010 John Wiley & Sons, Ltd.
The semi‐geostrophic diagnosis of vertical motion. II: Results for an idealized baroclinic wave life cycle
Authors: Thorpe Alan J. , Pedder Mike A. 
Published: November 2010

AbstractIn this paper we apply the method of solution of the semi‐geostrophic (SG) omega equation developed in Part I to data generated from a numerical simulation of an idealized dry adiabatic frictionless baroclinic wave life cycle. The aim is to compare quantitatively the quasi‐geostrophic (QG) and SG solutions for the vertical motion, and to relate these to the model vertical motion field. This comparison allows an evaluation of how practical, and accurate, it would be to use such balance theories to estimate vertical motion from atmospheric data. It is found that the QG solution tends to overestimate both ascent and descent in the cyclone. This overestimation is due both to an overestimation of the forcing and to a poor treatment of the large horizontal gradients of static stability produced as the tropopause descends near the cyclone centre. As the SG theory more faithfully represents the Ertel‐Rossby potential vorticity (PV), the vertical motion which is implied by this distribution of PV is also quantitatively more similar to the model vertical motion than that produced by the QG theory. The PV distribution affects the vertical motion via the forcing and via explicit account of horizontal gradients of the local static stability distribution which appear in the differential operator in the omega equation. The residual between the vertical motion predicted by the SG, or any other balance, theory and that given by the model is produced partly by any inertia‐gravity wave activity and partly by inaccuracies in the assumed balance condition.
Planetary wave modes in the thermocline: Non‐Doppler‐shift mode, advective mode and Green mode
Authors: Liu Zhengyu 
Published: November 2010

AbstractA quasi‐geostrophic theory is proposed for planetary waves in the extratropical thermocline. It is shown that planetary wave propagation, structure and stability can be affected significantly by the mean thermocline flow. One major planetary wave mode is the non‐Doppler‐shift mode, which resembles the first baroclinic mode and has a strong signature in both the sea surface height and the bottom of the thermocline. This mode propagates westward regardless of the mean flow. However, consistent with recent works, the westward propagation speed can be modestly enhanced by the mean flow. Another major planetary wave mode is the advective mode which bears some resemblance to the second baroclinic mode and has a strong signature in the upper thermocline temperature field.In the region of strong westward thermocline flow and shear, such as the south‐western part of the North Pacific subtropical gyre, an unstable Green mode is produced by the coupling of the non‐Doppler‐shift mode and the advective mode. This unstable Green mode may have e‐folding times of a few years for a wave hundreds of kilometers in length. The structure of the Green mode contains the features of the second baroclinic mode with a strong signature in the upper‐thermocline. The Green mode always propagates westward. Finally, we discuss the relevance of our theory to recent observations.
Gravity‐wave drag produced by Madeira
Authors: Miranda Pedro M. A. , Ferreira João Jacinto , Thorpe Alan J. 
Published: November 2010

AbstractThe gravity‐wave drag exerted on the atmosphere by an isolated three‐dimensional mountain is here evaluated from observational data. The representation of such drag in numerical weather‐prediction models is known to be of considerable importance, and this study provides some rare field measurements for input and verification of parametrization schemes.The results of a microbarograph experiment performed in the spring of 1993 on the Island of Madeira are presented. The data obtained with thermostatically adjusted microbarographs, located on the two sides of the island, are analysed in terms of the gravity‐wave drag produced by the mountain. The time series obtained show a high degree of coherency, consistent with the idea that they represent a mesoscale signal, not significantly affected by small‐scale perturbations. The pressure signal at each station shows a superposition of different oscillations including a 5–7 day synoptic oscillation, a 12‐hour tide and an irregular oscillation with an amplitude of about 2 hPa, which can be associated with gravity‐wave drag. The pressure differences across the island essentially contain the gravity‐wave drag signal, which somewhat surprisingly correlates rather well with linear estimates. The estimated drag has an average value similar to those observed in the PYREX experiment, despite the lower wind speeds typical of Madeira.
An improved fast radiative transfer model for assimilation of satellite radiance observations
Authors: Saunders R. , Matricardi M. , Brunel P. 
Published: November 2010

AbstractTo assimilate atmospheric and surface radiance measurements from satellites in a numerical weather prediction model, a fast radiative transfer model is required to compute radiances from the model first guess fields at every observation point. Such a model for satellite infrared and microwave radiance measurements is used operationally for the assimilation of TIROS operational vertical sounder radiances at the European Centre for Medium‐Range Weather Forecasts. An improved version of this model has been developed which requires ozone, in addition to temperature and water vapour, in the input profile and it has been generalized to compute radiances for other satellite radiometers using the same code. Instruments such as the high resolution infrared radiation sounder and the advanced microwave sounding unit on the National Oceanic and Atmospheric Administration polar orbiters, the METEOSAT water vapour imager and the Geostationary Operational Environmental Satellite infrared sounder have been simulated. It is demonstrated, by comparisons with line‐by‐line model computed radiances, that the fast model can reproduce the line‐by‐line model radiances for the TIROS operational vertical sounder stratospheric temperature sounding channels to an accuracy below the instrumental noise. The tropospheric, surface sensing, water vapour and ozone channel radiances cannot be predicted to such an accuracy, but still accurately enough for numerical weather prediction assimilation. A comparison of measured TIROS operational vertical sounder radiances with predicted values from numerical weather prediction model analyses gives larger differences than would be expected from the combination of the fast model and instrument related errors for most channels. The validity of the tangent linear approximation of the model gradient for typical radiance departures is also explored, with several examples, for the high resolution infrared radiation sounder/advanced microwave sounding unit instrument combination. The tangent‐linear approximation is valid for temperature but significant departures from linearity about the first guess profile are observed for water vapour and ozone. Cloud affected infrared radiances have a highly non‐linear response.
The effect of the iterative triple and quadruple cluster amplitudes on the adiabatic potential curve in the coupled cluster calculations of the ground electronic state of the Yb dimer
Authors: Mosyagin N. S. , Petrov A. N. , Titov A. V. 
Published: November 2010

AbstractThe dissociation energy, equilibrium internuclear distance, and spectroscopic constants for the 1Σ ground state of the Yb2 molecule are calculated. The relativistic effects are introduced through generalized relativistic effective core potentials with very high precision. The scalar relativistic coupled cluster method particularly well suited for closed‐shell van der Waals systems is used for the correlation treatment. Extensive generalized correlation basis sets were constructed and used. The relatively small corrections for high‐order cluster amplitudes and spin—orbit interactions are taken into account using smaller basis sets and the spin—orbit density functional theory. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Zinc selenide nanoclusters: Static dipole polarizability and electronic properties
Authors: Mohajeri Afshan , Alipour Mojtaba 
Published: November 2010

AbstractThe structural stability and electronic properties of stoichiometric zinc selenide (ZnSe) nanoclusters up to 20 atoms have been systematically investigated in the framework of density functional theory. The similarity function has been used to investigate the extent that the clusters are similar to the pure ZnSe or to each other. Energetically, the relative stability of ZnSe clusters at different sizes is studied by calculating the second‐order difference in total energy. The size evolution of several reactivity descriptors such as static dipole polarizability and chemical hardness has been determined for ZnSe clusters. In addition, the minimum polarizability principle and principle of maximum hardness are used to characterize the magic clusters. Moreover, it is shown that the differential mean polarizability can be also a useful quantity to characterize the stability of the studied clusters. It is found that there is a strong inverse correlation between the static dipole polarizability and the ionization potential of the ZnSe clusters. Similarly, the softness has also been shown to mostly correlate with the static dipole polarizability of these clusters. This work thus will have some important implications for the calculation of polarizability of ZnSe clusters in terms of the corresponding ionization potentials and softness. For each property, a comparison between studied clusters here and the zinc sulfide clusters from our recent article is presented. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Evaluation of the LTQ‐Orbitrap mass spectrometer for the analysis of polymerase chain reaction products
Authors: Manduzio Hélène , Ezan Eric , Fenaille François 
Published: November 2010

AbstractWe have investigated the potential and robustness of the off‐line coupling of polymerase chain reaction (PCR) with electrospray ionization mass spectrometry (ESI‐MS), for further applications in the screening of single‐nucleotide polymorphisms (SNPs). This was based on recently reported data demonstrating that anion‐exchange solid‐phase extraction was the most efficient technique for efficiently desalting PCR products, with a recovery of ∼70%. Results showed that this purification approach efficiently removes almost all the chemicals commonly added to PCR buffers. ESI‐MS analysis of a model 114‐bp PCR product performed on the LTQ‐Orbitrap instrument demonstrated that detection limits in the nM range along with an average mass measurement uncertainty of 9.15 ± 7.11 ppm can be routinely obtained using an external calibration. The PCR/ESI‐MS platform was able to detect just a few copies of a targeted oligonucleotide. However, it was shown that if two PCR products are present in a mixture in a ratio higher than 10 to 1, the lower abundance one might not be reproducibly detected. Applications to SNPs demonstrated that an LTQ‐Orbitrap with a resolution of 30 000 (at m/z 400) easily identified a single (A ↔ G) switch, i.e. a 16 Da difference, in binary mixtures of ∼ 35 kDa PCR products. Complementary experiments also showed that the combination of endonucleases and ESI‐MS could be used to confirm base composition and sequence, and thus to screen for unknown polymorphisms in specific sequences. For example, a single (T ↔ A) switch (9 Da mass difference) was successfully identified in a 114‐bp PCR product. Copyright © 2010 John Wiley & Sons, Ltd.
Study of plasma metabolic profiling and biomarkers of chronic unpredictable mild stress rats based on gas chromatography/mass spectrometry
Authors: Li Zhen‐Yu , Zheng Xing‐Yu , Gao Xiao‐Xia , Zhou Yu‐Zhi , Sun Hai‐Feng , Zhang Li‐Zeng , Guo Xiao‐Qing , Du Guan‐Hua , Qin Xue‐Mei 
Published: November 2010

AbstractA metabolomic investigation of chronic unpredictable mild stress (CUMS) rats was carried out. Plasma obtained from Sprague‐Dawley (SD) rats treated by CUMS was analyzed using gas chromatography/mass spectrometry. Thirty‐seven metabolites were identified among the detected compounds. Subsequent data analysis using the t test and principal component analysis (PCA) revealed significant metabolic changes in the rats' plasma after CUMS treatment. Clear separation between the model and control group was achieved, and the level of twelve metabolites, including amino acids, sugar, organic acids and fatty acids, were significantly different between plasma samples from the controls and CUMS group. These observations suggested that the depressed state may be associated with perturbation of amino acid metabolism, energy metabolism and glycometabolism. The study suggested that the metabolomics approach could be used as a potential powerful tool to investigate the biochemical change in certain physiopathological conditions, such as depression, as an early diagnostic means. Copyright © 2010 John Wiley & Sons, Ltd.
On the limits of clustering in high dimensions via cost functions
Authors: Koepke Hoyt A. , Clarke Bertrand S. 
Published: November 2010

AbstractThis paper establishes a negative result for clustering: above a certain ratio of random noise to nonrandom information, it is impossible for a large class of cost functions to distinguish between two partitions of a data set. In particular, it is shown that as the dimension increases, the ability to distinguish an accurate partitioning from an inaccurate one is lost unless the informative components are both sufficiently numerous and sufficiently informative. We examine squared error cost functions in detail. More generally, it is seen that the VC‐dimension is an essential hypothesis for the class of cost functions to satisfy for an impossibility proof to be feasible. Separately, we provide bounds on the probabilistic behavior of cost functions that show how rapidly the ability to distinguish two clusterings decays. In two examples, one simulated and one with genomic data, bounds on the ability of squared‐error and other cost functions to distinguish between two partitions are computed. Thus, one should not rely on clustering results alone for high dimensional low sample size data and one should do feature selection. Copyright © 2010 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 4: 30–53 2011