bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lake/watershed sulfur budgets and their response to decreases in atmospheric sulfur deposition: watershed and climate controls
Authors: Mitchell Myron J. , Driscoll Charles T. , McHale Patrick J. , Roy Karen M. , Dong Zheng 
Published: December 2012

AbstractAtmospheric sulfur (S) emissions peaked in North America in the early 1970s followed by declines in S deposition and sulfate (SO42−) concentrations in surface waters. Changes in S biogeochemistry affect the mobilization of toxic (Al+3, H+) and nutrient (Ca2+, Mg2+, K+) cations, and the acid–base status of ecosystems. We focused on lake/watersheds in the Adirondack Mountains of New York, USA, one of the most acid‐sensitive and acid‐impacted regions in North America. We used 16 of the 17 original Adirondack Long‐Term Monitoring Lakes from 1984 through 2010 and found significant declines (−2.14 µmolc l−1 year−1) in SO42− concentrations. There were significant declines (−0.28 kg S ha−1 year−1) in total S deposition for all lake/watersheds. We constructed S mass balances for 14 lakes/watersheds from wet and dry S deposition and SO42− loss from drainage and found a comparable decline (−0.26 kg S ha−1 year−1) in lake SO42− export. There was a discrepancy (mean 2.34 kg S ha−1 year−1) between atmospheric S deposition and watershed S loss due to internal S sources. Using major solute chemistry including dissolved silica and watershed characteristics, it was evident that the watershed S budget discrepancy increased with thickness of surficial deposits. The annual discrepancies in S mass balances were strongly linked with annual watershed discharge. These results suggest that internal S sources are becoming increasingly important as atmospheric S inputs have declined. The internal SO42− supply of watersheds decreased concomitantly with lake acid neutralizing capacity (ANC). These findings suggest that the limited contributions from internal sources of SO42− will facilitate the recovery of ANC from those lake/watersheds with the lowest ANC. With long‐term decreases in atmospheric S deposition, the effects of climate, especially increases in precipitation, will play an increasingly important role in regulating S budgets and the amount of SO42− mobilized from internal watershed sources. Copyright © 2012 John Wiley & Sons, Ltd.
Analgesia induced by localized injection of opiate peptides into the brain of infant rats
Authors: Barr G.A. , Wang S. 
Published: December 2012

AbstractBackgroundStimulation of a variety of brain sites electrically or by opiates activates descending inhibitory pathways to attenuate noxious input to the spinal cord dorsal horn and produce analgesia. Analgesia induced by electrical stimulation of the periaqueductal grey (PAG) of the midbrain or medial rostral ventral medulla (RVM) matures late, towards the end or past the pre‐weaning period. Descending facilitation takes precedence over inhibition. Yet opiates injected intracerebroventricularly or directly into the PAG induce analgesia relatively early in development. Our goal was to re‐examine the role of opiates specific to individual receptor types in analgesia at several supraspinal sites.MethodsAntinociception was tested following microinjection of DAMGO (μ‐opiate agonist), DPDPE (∂‐opiate agonist) or U50,488 (κ‐opiate agonist) into the PAG, RVM or dorsal lateral pons (DLP) in 3‐, 10‐ and 14‐day‐old rats.ResultsDAMGO produced analgesia at 3 days of age at each brain area; the RVM was the most effective and the dorsal PAG was the least effective site. DPDPE produced modest analgesia at 10 and 14 days of age at the ventral PAG, RVM or DLP, but not the dorsal PAG. U50,488H was ineffective at all sites and all ages.ConclusionsAntinociception could be elicited at all three sites by DAMGO as early as 3 days of age and DPDPE at 10 and 14 days of age. The degree of analgesia increased gradually during the first 2 weeks of life, and likely reflects the maturation of connections within the brain and of descending inhibitory paths from these sites.
A dual‐functionally modified chitosan derivative for efficient liver‐targeted gene delivery
Authors: Xiao Bo , Wang Xiaoyu , Qiu Zhiye , Ma Jun , Zhou Lei , Wan Ying , Zhang Shengmin 
Published: December 2012

AbstractGalactosylated chitosan‐hydroxypropyltrimethylammonium (gal‐HTCC) was synthesized by galactosylating and quaternizing chitosan to endue chitosan with targeting specificity for potential applications as gene vectors. The composition and physicochemical properties of gal‐HTCC were characterized by FT‐IR, 1H NMR, elemental analysis, X‐ray diffraction, and turbidity measurement. It was found that water‐soluble gal‐HTCC showed a more amorphous structure than chitosan, and it also had a much better plasmid condensation capability than galactosylated chitosan. Cytotoxicity measurements revealed that gal‐HTCC showed significantly lower cytotoxicity in HepG2 and HeLa cell lines compared to branched polyethylenimine (bPEI, 25 kDa) which was used as a positive control. The nanoparticles (NPs) consisted of gal‐HTCC and plasmid DNA had desirable particle size (around 250 nm) with a narrow size distribution. Confocal laser scanning microscopy confirmed that NPs could be internalized and transported to the nucleus efficiently within 6 h. In vitro gene transfection results indicated that gal‐HTCC had significantly higher transfection efficiency (7‐ to 32‐fold) compared to chitosan and gal‐chitosan for targetable delivery of pGL3 luciferase plasmid to HepG2, and its transfection efficiency was highly inhibited in the presence of galactose (20 mM). All these results suggest that gal‐HTCC can function as a promising nonviral gene vector for efficient liver‐targeted gene delivery. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Modulation of the African–Indian rainfall relationship by the thermal variability over the Mediterranean Sea in northern summer
Authors: Fontaine Bernard , Pham Xuan Thanh 
Published: December 2012

ABSTRACTThis statistical study stresses the relationship between different types of thermal anomaly patterns observed in Mediterranean areas and rainfall amounts in the African and Indian monsoon regions at the inter‐decadal (>10 years), inter‐annual (<10 years), intra‐seasonal (>10 d) and synoptic (3–9 d) scales through composite and correlation analyses performed on different atmospheric reanalyses and outgoing longwave radiation OLR data. The results show that the warmest situations registered over the whole Mediterranean Sea are concomitant of higher amounts in the African and Indian monsoon regions, contributing therefore to a positive African/Indian correlation. By contrast this correlation reverses when thermal variations between the eastern and western Mediterranean basins are considered: One observes higher African (lower Indian) rainfall with southwesterly (northeasterly) wind anomalies and an enhancement of the 3–9 d wave activity over the African continent associated with a northeastward extension of the main African Easterly Jet axis that favours wind shear and African easterly wave activity in the mid troposphere. More generally, eastern Mediterranean warming is synchronous of multiple atmospheric signals consistent with an intensification of moist convection, mid‐level ascents and integrated moisture content in the atmospheric column over Africa. The reverse is observed in Indian regions and appears compatible with the Rodwell–Hoskins mechanism.
A methodology for statistically downscaling seasonal snow cover characteristics over the Northeastern United States
Authors: Tryhorn Lee , DeGaetano Art 
Published: December 2012

ABSTRACTSnow cover amount and duration have a large role in both the natural and anthropogenic systems of the Northeast United States. Any changes in the climatology of the amount, duration, and timing of the snowpack may have long‐lasting environmental and economic consequences. At present, the principal tools used to examine future climatic changes are general circulation models; however, they do not provide information at the scales required for investigating many of the impacts in which snow plays a major role. In order to address this gap, a statistical downscaling methodology for simulating climatological snow cover parameters was developed. The methodology utilizes the Statistical DownScaling Model to construct climate change scenarios at daily time scales that are subsequently evaluated based on their ability to reproduce seasonal snow cover statistics. Two different observational datasets (station and gridded) were used as predictands and empirical relationships were created between the predictands and regional scale predictors. The methodology was tested at 20 locations across the Northeast and was then applied to output from HadCM3 under the A2 and B2 emissions scenarios. The methodology performed well at capturing key properties of station‐based snow cover over a range of climates and was found to perform better than the technique used in previous work in the Northeast. By the end of the century, the projections revealed characteristics that are consistent with declining snow cover, yet there are likely to be regional variations in the next several decades, especially when elevation is considered.
Residue depletion of nifuroxazide in broiler chicken
Authors: Gao Feng , Zhang Qi Di , Zhang Zhen Hong , Yan Xiao Dong , Zhang Hui Cai , Wang Jian Ping 
Published: December 2012

AbstractBackgroundSeveral nitrofuran drugs have been prohibited for use in food producing animals due to their carcinogenic and mutagenic effects. However, one of the nitrofurans, nifuroxazide, is still used as a veterinary drug in some countries. This study was conducted to investigate the residue depletion of nifuroxazide in broiler chicken. Chickens were fed with dietary feeds containing 50 mg kg−1 of nifuroxazide for seven consecutive days. Liver, kidney, muscle and plasma samples were collected at different withdrawal periods, and the residues of parent nifuroxazide and its acid‐hydrolysable side chain, 4‐hydroxybenzhydrazide (HBH), in these samples were determined.ResultsNifuroxazide was metabolised in vivo and its metabolite HBH was formed. Parent nifuroxazide was not detectable in these samples after 14 days of cessation. HBH was detectable in these samples even after 28 days of cessation and the total HBH residues were higher than 1.0 ng g−1. Furthermore, the residue level of tissue bound HBH was much higher than that of free HBH.ConclusionThe tissue‐bound HBH could be used as a marker to monitor the residue of nifuroxazide in chicken and the best target tissue should be liver. This is the first paper reporting the residue depletion of nifuroxazide in chicken.© 2012 Society of Chemical Industry
Poly(2‐oxazoline)‐derived Contact Biocides: Contributions to the Understanding of Antimicrobial Activity
Authors: Kelly Andrew M. , Kaltenhauser Verena , Mühlbacher Inge , Rametsteiner Karl , Kren Harald , Slugovc Christian , Stelzer Franz , Wiesbrock Frank 
Published: December 2012

AbstractA set of poly(2‐oxazoline)‐derived (co‐)polymers was prepared by microwave‐assisted polymerizations and acid‐mediated hydrolysis and tested for antimicrobial activity in 50 × 50 × 2 mm PP compound plates containing 5 wt% of the polymers. Antimicrobial activity against gram‐negative E. coli and P. aeruginosa as well as C. albicans depended only on the degree of hydrolysis, while antimicrobial activity against gram‐positive S. aureus was only observed for hydrolyzed poly(2‐nonyl‐2‐oxazoline)s. The surface energies of the compound plates compared to pure PP were hardly altered, and the compounds can be considered as alternatives for PP. The presence of the biocide additives at the surface of the PP compound plates could be shown by combined ATR‐IR, zeta potential, and SEM‐EDX measurements. Antimicrobial activity was maintained during double incubation as well as for lowered amounts of the biocide additive of 1% in PP compound plates. magnified image
Core–Shell Capsules Based on Supramolecular Hydrogels Show Shell‐Related Erosion and Release Due to Confinement
Authors: Guo Mingyu , Cao Xiaoyu , Meijer E. W. , Dankers Patricia Y. W. 
Published: December 2012

AbstractHydrogel‐containing core–shell capsules are useful as drug delivery vehicles for many biomedical applications, especially when release of incorporated guests can be controlled. Here, we developed a one‐step organic solvent‐free method to prepare such core–shell capsules using a synthetic and a natural supramolecular hydrogel, for the core and shell, respectively. A solution containing ureido‐pyrimidinone modified poly(ethylene glycol) hydrogelators and calcium chloride was drop‐wise added to an alginate solution, yielding core–shell structures. It was found that the outer shell provides a confined space for the inner supramolecular hydrogel and therefore prevents swelling of the core. This consequently slows down both erosion of the less stable core, and release of dextran guests. magnified image
Robust Iterative Solution of a Class of Time‐Dependent Optimal Control Problems
Authors: Pearson John W. , Stoll Martin , Wathen Andrew J. 
Published: December 2012

AbstractThe fast iterative solution of optimal control problems, and in particular PDE‐constrained optimization problems, has become an active area of research in applied mathematics and numerical analysis. In this paper, we consider the solution of a class of time‐dependent PDE‐constrained optimization problems, specifically the distributed control of the heat equation. We develop a strategy to approximate the (1, 1)‐block and Schur complement of the saddle point system that results from solving this problem, and therefore derive a block diagonal preconditioner to be used within the MINRES algorithm. We present numerical results to demonstrate that this approach yields a robust solver with respect to step‐size and regularization parameter. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The nonequispaced FFT on graphics processing units
Authors: Kunis Susanne , Kunis Stefan 
Published: December 2012

AbstractWithout doubt, the fast Fourier transform (FFT) belongs to the algorithms with large impact on science and engineering. By appropriate approximations, this scheme has been generalized for arbitrary spatial sampling points. This so called nonequispaced FFT is the core of the sequential NFFT3 library and we discuss its computational costs in detail. On the other hand, programmable graphics processing units have evolved into highly parallel, multithreaded, manycore processors with enormous computational capacity and very high memory bandwidth. By means of the so called Compute Unified Device Architecture (CUDA), we parallelized the nonequispaced FFT using the CUDA FFT library and a dedicated parallelization of the approximation scheme. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preconditioned Block‐Iterative Methods on GPUs
Authors: Naumov Maxim 
Published: December 2012

AbstractAn implementation of the incomplete‐LU/Cholesky preconditioned block‐iterative methods on the Graphics Processing Units (GPUs) using the CUDA parallel programming model is presented. In particular, we focus on the tradeoffs associated with the sparse matrix‐vector multiplication with multiple vectors, sparse triangular solve with multiple right‐hand‐sides (rhs) as well as incomplete factorization with 0 fill‐in. We use these building blocks to implement the block‐CG and BiCGStab iterative methods for the symmetric positive definite (s.p.d.) and nonsymmetric linear systems, respectively. Also, in our numerical experiments we show that the implementation of the preconditioned block‐iterative methods using the CUSPARSE library on the GPU achieves an average of 3× speedup over their MKL implementation on the CPU. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Twinned martensite configurations arising as ground states of a two‐well discrete Hamiltonian
Authors: Kitavtsev G. , Luckhaus S. 
Published: December 2012

AbstractIn this paper we construct and analyze a two‐well Hamiltonian on 2D atomic lattice considered with nonconvex interactions. Two wells of the Hamiltonian are given by two rank‐one connected martensitic twins, respectively. Our combined analytical and numerical results show that the structure of ground states under appropriate boundary conditions is close to the macroscopically expected twinned configuration plus additional exponential boundary layers localized near the twinning interface. Besides, we proceed to continuum limit, show asymptotic piece‐wise rigidity of minimizing sequences and derive the limiting form of their surface energy. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nano to Micro – Perspectives for Homogenization in Crystalline Solids
Authors: Schröder Jörg , Eidel Bernhard , Brands Dominik , Balzani Daniel 
Published: December 2012

AbstractThis paper communicates perspectives and ideas for lengthscale‐transitions for metallic materials from nano over micro to macro. For micro‐macro transitions, the FE2‐method is described, where a top‐down perspective manifests the need to introduce even finer‐scaled information than typically considered on the microscale, such as e.g. atomistic details. In contrast, the description of the Quasi‐Continuum method as an atomistic‐continuum transition method naturally takes the perspective of a bottom‐up approach, that starts at the nanoscale and aims at larger length scales by finite element techniques. We describe the main differences between the two multiscale frameworks referring to atomistics and those which pertain to continuum mechanics. Perspectives are proposed for combining and coupling the different frameworks in a consistent way. Finally we identify fields of applications, where nanoscale information is introduced to micro‐models, either via sequential/hierarchical coupling or in concurrent frameworks. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micro‐to‐macro transitions for continua with surface structure at the microscale
Authors: Javili Ali , McBride Andrew , Mergheim Julia , Steinmann Paul , Schmidt Ulrike 
Published: December 2012

AbstractA framework for micro‐to‐macro transitions is developed that accounts for the effect of size at the microscopic scale. This is done by endowing the surfaces of the microscopic features with their own (energetic) structure using the theory of surface elasticity. Following a standard first‐order ansatz on the microscopic motion in terms of the macroscopic deformation gradient, a Hill‐type averaging condition is used to link the two scales. The surface elasticity theory introduces two additional microscopic length scales: the ratio of the bulk volume to the energetic surface area, and the ratio of the surface and bulk Helmholtz energies. The influence of these microscopic length scales is elucidated via a series of numerical examples performed using the finite element method. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Variational Homogenization of Micro‐Electro‐Elasticity
Authors: Zäh Dominic , Miehe Christian 
Published: December 2012

AbstractUnderstanding of micromechanical mechanisms in functional materials with electro‐mechanical coupling is a highly demanding area of simulation technology and increasing interest has been shown in the last decades. Smart materials are characterized by microstructural properties, which can be changed by external stress and electric field stimuli, and hence find use as the active components in sensors and actuators. In this context, a key challenge is to combine models for microscopic electric domain evolution with variational principles of homogenization. We outline a variational‐based micro‐electro‐elastic model for the micro‐structural evolution of electric domains in ferroelectric ceramics. The micro‐to‐macro transition is performed on the basis of variational principles, extending purely mechanical formulations to coupled electro‐mechanics. We focus on an electro‐mechanical Boltzmann continuum on the macro‐scale with mechanical displacement and electric potential as primary variables. The material model on the micro‐scale is described by a gradient‐extended continuum formulation taking into account the polarization vector field and its gradient, see Landis [1] and Schrade et al. [2] for conceptually similar approaches. A crucial aspect of the proposed homogenization analysis is the derivation of appropriate boundary conditions on the surface of the representative volume element. In this work we derive stiff Dirichlet‐type, soft Neumann‐type, and periodic boundary constraints starting from a generalized Hill‐Mandel macrohomogeneity condition. Furthermore, we propose techniques to incorporate these boundary conditions in the variational principles of homogenization by means of Lagrange multiplier methods. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Second order asymptotics for the propagation speed of interfaces in the Allen‐Cahn phase field model for elastic solids
Authors: Alber Hans‐Dieter , Markert Bernd 
Published: December 2012

AbstractFor a phase field model, which consists of the elasticity equations coupled to the Allen‐Cahn equation, we state an asymptotic expansion for the propagation speed of the diffusive interface. The error of the expansion is of order η2, where η is the width of the interface. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An approach for decomposition of finite rotations
Authors: Mladenova Clementina D. , Mladenov Ivaïlo M. 
Published: December 2012

AbstractBased on Lie groups theory, this work considers the problem of decomposition of a given rotation into three successive finite rotations with prescribed in advance axes. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Alternative approaches to the incorporation of control constraints in multibody dynamics
Authors: Yang Yinping , Betsch Peter 
Published: December 2012

AbstractControl constraints can be used to prescribe the motion in the inverse dynamics of multibody systems. If the number of control inputs is lower than the degrees of freedom, this kind of mechanical system is called underactuated system. The solution of such partly specified system is a challenging task due to the underactuation property. The description of underactuated systems can be based on either minimal coordinates or redundant coordinates. The resulting governing equations show the form of differential‐algebraic equations (DAEs) with a mixed set of holonomic and control constraints. The index of the DAEs may exceed three and alternative projection methods will be applied to reduce the index to three. Numerical examples are used to compare the alternative projection methods. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Zur Wechselwirkung in Elastomeren und deren Auswirkung auf das Fahrverhalten von PKW
Authors: Lohse Christian , Kröger Matthias 
Published: December 2012

AbstractElastomerbauteile in Fahrwerken dienen der gezielten Beeinflussung der Gesamtelastokinematik. Im Entwicklungsprozess versucht der Konstrukteur die optimale Lösung für den jeweiligen Anwendungsfall zwischen Fahrdynamik inbesondere bei Kurvenfahrt und Fahrkomfort zu finden. Zusätzlich wird in diversen Achskonstruktionen diesen Bauteilen eine die Fahrzeugsicherheit beeinflussende Funktion überlassen. Die Kenntnis des komplexen Bauteilverhaltens, inbesondere der mechanischen Wechselwirkungen, ist daher wünschenswert. Mit einer Kombination aus Finite‐Elemente‐Analysen und der Mehrkörpersimulation können diese Effekte untersucht werden. An einem Beispiel aus der Fahrzeugdynmaik wird gezeigt, in welcher Größenordnung sich der Einfluss der Wechselwirkungen auf das Fahrverhalten bewegen kann. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)