bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phytochelatin induction by selenate in Chlorella vulgaris, and regulation of effect by sulfate levels
Authors: Simmons Denina B. D , Emery R. J. Neil 
Published: October 2010

Abstract
Phytochelatins (PCs) are short metal detoxification peptides made from the sulfur-rich molecule glutathione. The production of PCs by algae caused by Se exposure has never been studied, although many algae accumulate Se, forming Se-rich proteins and peptides, and higher plants have demonstrated PC production when treated with Se; therefore, a goal of the current study was to examine whether Se induces PC production in algae. Furthermore, selenate is thought to compete with sulfate in the S assimilation pathway, and sulfate therefore may have a protective effect against the toxic effects of high doses of Se in algae. Hence, the interaction of selenate and sulfate was investigated with respect to the induction of PCs. Chlorella vulgaris was cultured in media with either low (31.2 µM) or high (312 µM) concentrations of sulfate. These cultures were exposed to selenate in doses of 7, 35, and 70 nM for 48 h. In a separate treatment, Cd (890 nM) was added as a positive PC-inducing control, and one no-metal negative control was used. Total Se and Se speciation were determined, and glutathione, phytochelatin-2, and phytochelatin-3 were quantified in each of cell digests, cell medium, and cell lysates. We found that PCs and their precursor glutathione were induced by selenate as well as by a Cd control. The high concentration of sulfate was able to counter selenate-induced production of PCs and glutathione. These data support two possible mechanisms: a negative feedback system in the S assimilation pathway that affects PC production when sulfate is abundant, and competition for uptake at the ion transport level between selenate and sulfate. Environ. Toxicol. Chem. 2011;30:469–476. © 2010 SETAC
Comparing effects of low levels of herbicides on greenhouse- and field-grown potatoes (Solanum tuberosum L.), soybeans (Glycine max L.), and peas (Pisum sativum L.)
Authors: Pfleeger Thomas , Olszyk David , Lee E. Henry , Plocher Milton 
Published: October 2010

Abstract
Although laboratory toxicology tests are generally easy to perform, cost effective, and readily interpreted, they have been questioned for their environmental relevance. In contrast, field tests are considered realistic while producing results that are difficult to interpret and expensive to obtain. Toxicology tests were conducted on potatoes, peas, and soybeans grown in a native soil in pots in the greenhouse and were compared to plants grown outside under natural environmental conditions to determine toxicological differences between environments, whether different plant developmental stages were more sensitive to herbicides, and whether these species were good candidates for plant reproductive tests. The reproductive and vegetative endpoints of the greenhouse plants and field-grown plants were also compared. The herbicides bromoxynil, glyphosate, MCPA ([4-chloro-2-methylphenoxy] acetic acid), and sulfometuron-methyl were applied at below field application rates to potato plants at two developmental stages. Peas and soybeans were exposed to sulfometuron-methyl at similar rates at three developmental stages. The effective herbicide concentrations producing a 25% reduction in a given measure differed between experimental conditions but were generally within a single order of magnitude within a species, even though there were differences in plant morphology. This study demonstrated that potatoes, peas, and soybeans grown in pots in a greenhouse produce phytotoxicity results similar to those grown outside in pots; that reproductive endpoints in many cases were more sensitive than vegetative ones; and that potato and pea plants are reasonable candidates for asexual and sexual reproductive phytotoxicity tests, respectively. Plants grown in pots in a greenhouse and outside varied little in toxicity. However, extrapolating those toxicity results to native plant communities in the field is basically unknown and in need of research. Environ. Toxicol. Chem. 2011;30:455–468. © 2010 SETAC
Application of ambient analysis techniques for the estimation of electromechanical oscillations from measured PMU data in four different power systems
Authors: Vanfretti Luigi , Dosiek Luke , Pierre John W. , Trudnowski Daniel , Chow Joe H. , García‐Valle Rodrigo , Aliyu Usman 
Published: October 2010

AbstractThe application of advanced signal processing techniques to power system measurement data for the estimation of dynamic properties has been a research subject for over two decades. Several techniques have been applied to transient (orringdown) data, ambient data, and to probing data. Some of these methodologies have been included in off‐line analysis software, and are now being incorporated into software tools used in control rooms for monitoring the near real‐time behavior of power system dynamics. In this paper we illustrate the practical application of some ambient analysis methods for electromechanical mode estimation in different power systems. We apply these techniques to phasor measurement unit (PMU) data from stored archives of several hours originating from the US Eastern Interconnection (EI), the Western Electricity Coordinating Council (WECC), the Nordic Power System, and time‐synchronized Frequency Disturbance Recorder (FDR) data from Nigeria. It is shown that available signal processing tools are readily applicable for analysis of different power systems, regardless of their specific dynamic characteristics. The discussions and results in this paper are of value to power system operators and planners as they provide information of the applicability of these techniquesviareadily available signal processing tools, and in addition, it is shown how to critically analyze the results obtained with these methods. Copyright © 2010 John Wiley & Sons, Ltd.
Using adjoint error estimation techniques for elastohydrodynamic lubrication line contact problems
Authors: Hart D. E. , Berzins M. , Goodyer C. E. , Jimack P. K. 
Published: October 2010

AbstractThe use of an adjoint technique for goal‐based error estimation described by Hartit et al. (Int. J. Numer. Meth. Fluids 2005; 47:1069–1074) is extended to the numerical solution of free boundary problems that arise in elastohydrodynamic lubrication (EHL). EHL systems are highly nonlinear and consist of a thin‐film approximation of the flow of a non‐Newtonian lubricant which separates two bodies that are forced together by an applied load, coupled with a linear elastic model for the deformation of the bodies. A finite difference discretization of the line contact flow problem is presented, along with the numerical evaluation of an exact solution for the elastic deformation, and a moving grid representation of the free boundary that models cavitation at the outflow in this one‐dimensional case. The application of a goal‐based error estimate for this problem is then described. This estimate relies on the solution of an adjoint problem; its effectiveness is demonstrated for the physically important goal of the total friction through the contact. Finally, the application of this error estimate to drive local mesh refinement is demonstrated. Copyright © 2010 John Wiley & Sons, Ltd.
Numerical simulation of compressible turbulent flow via improved gas‐kinetic BGK scheme
Authors: Xiong Shengwei , Zhong Chengwen , Zhuo Congshan , Li Kai , Chen Xiaopeng , Cao Jun 
Published: October 2010

AbstractIn order to solve compressible turbulent flow problems, this study focuses on incorporating the Spalart–Allmaras turbulence model into gas‐kinetic BGK (Bhatnagar–Gross–Krook) scheme. The Spalart–Allmaras turbulence model is solved using finite difference discretization. The variables on the cell interface are interpolated via the van Leer limiter in the reconstruction stage. Simulation of subsonic and transonic flow over a NACA0012 airfoil has been implemented using two‐dimensional body‐fitted grids. The numerical results obtained appear in good agreement with the AGARD results, demonstrating the effectiveness and usefulness of the strategy of coupling the Spalart–Allmaras turbulence model with the BGK scheme for compressible turbulent flow simulation. Copyright © 2010 John Wiley & Sons, Ltd.
A multidimensional HLL‐Riemann solver for non‐linear hyperbolic systems
Authors: Capdeville G. 
Published: October 2010

AbstractThis article presents a numerical model that enables to solve on unstructured triangular meshes and with a high order of accuracy, Riemann problems that appear when solving hyperbolic systems.For this purpose, we use a MUSCL‐like procedure in a ‘cell‐vertex’ finite‐volume framework.In the first part of this procedure, we devise a four‐state bi‐dimensional HLL solver (HLL‐2D). This solver is based upon the Riemann problem generated at the barycenter of a triangular cell, from the surrounding cell‐averages. A new three‐wave model makes it possible to solve this problem, approximately. A first‐order version of the bi‐dimensional Riemann solver is then generated for discretizing the full compressible Euler equations.In the second part of the MUSCL procedure, we develop a polynomial reconstruction that uses all the surrounding numerical data of a given point, to give at best third‐order accuracy. The resulting over determined system is solved by using a least‐square methodology. To enforce monotonicity conditions into the polynomial interpolation, we use and adapt the monotonicity‐preserving limiter, initially devised by Barth (AIAA Paper 90‐0013, 1990).Numerical tests and comparisons with competing numerical methods enable to identify the salient features of the whole model. Copyright © 2010 John Wiley & Sons, Ltd.
A heterogeneous multiscale modeling framework for hierarchical systems of partial differential equations
Authors: Masud Arif , Scovazzi Guglielmo 
Published: October 2010

AbstractThis paper presents a heterogeneous multiscale method with efficient interscale coupling for scale‐dependent phenomena modeled via a hierarchy of partial differential equations. Physics at the global level is governed by one set of partial differential equations, whereas features in the solution that are beyond the resolution capability of the coarser models are accounted for by the next refined set of differential equations. The proposed method seamlessly integrates different sets of equations governing physics at various levels, and represents a consistent top–down and bottom–up approach to multi‐model modeling problems. For the top–down coupling of equations, this method provides a variational residual‐based embedding of the response from the coarser or global system equations, into the corresponding local or refined system equations. To account for the effects of local phenomena on the global response of the system, the method also accommodates bottom–up embedding of the response from the local or refined mathematical models into the global or coarser model equations. The resulting framework thus provides a consistent way of coupling physics between disparate partial differential equations by means of up‐scaling and down‐scaling of the mathematical models. An integral aspect of the proposed framework is an uncertainty quantification and error estimation module. The structure of this error estimator is investigated and its mathematical implications are delineated. Copyright © 2010 John Wiley & Sons, Ltd.
Computer‐algebra multiple‐timescale method for spatially periodic thin‐film viscous‐flow problems
Authors: Groh Christian M. , Kelmanson Mark A. 
Published: October 2010

SUMMARYA flexible, fully automated, computer‐algebra algorithm is developed for solving a class of non‐linear partial‐differential evolution equations arising frequently in the modeling of two‐dimensional transient free‐surface viscous thin‐film flows. The method, which is formulated for solving spatially periodic problems, is based upon an explicit multiple‐timescale asymptotic approximation of the thin‐film thickness. It admits the resolution of diverse physical phenomena by employing a finite geometric progression of increasingly slow timescales.The method is implemented on a challenging test problem comprising the evolution of an annular film of viscous liquid, with a free surface, adhering to the exterior of a horizontal rotating circular cylinder; as a model for numerous industrially motivated coating flows, this benchmark problem has been analyzed in diverse numerical and theoretical studies, against whose results those of the present method are compared.The explicit algebraic form of the solution admits a study of large‐time evolutionary dynamics that lies beyond the reach of considerably more expensive conventional numerical solvers, thereby shedding new light on the hitherto‐undiscovered explicit dependence of large‐time evolutionary fluid dynamics in terms of independent parameters describing gravitational and capillary effects.The results obtained from the new computer‐algebra procedure are demonstrated to be in good agreement with those obtained from a bespoke efficient numerical integration method that is spectrally accurate in space and 8th‐order (Runge–Kutta) in time. Newly discovered mechanisms describing the decay of free‐surface wave modes, from arbitrary initial conditions to the steady state, are presented. Copyright © 2010 John Wiley & Sons, Ltd.
An implicit full Eulerian method for the fluid–structure interaction problem
Authors: Ii S. , Sugiyama K. , Takeuchi S. , Takagi S. , Matsumoto Y. 
Published: October 2010

AbstractA numerical method, which relaxes limitation of small time increment in fluid–structure interaction (FSI) simulations with hard solid, is developed based on a full Eulerian FSI model (Sugiyama et al. Comput. Mech. 2010; 46(1):147–157). In this model, the solid volume fraction is applied for describing the multicomponent material, and the left Cauchy‐Green deformation tensor is introduced to describe the deformation of the hyperelastic body. The transport equations for them are solved by finite difference formulation on a fixed Cartesian coordinate grid. In this paper, a simple implicit formulation is proposed for the elastic stress to avoid restriction and instability due to high stiffness. Both linear and nonlinear hyperelastic materials are treated by a unified formulation by introducing a fourth‐order Jacobian tensor to overcome the difficulty associated with the difference between the constitutive laws of solid and fluid. The numerical examples are carried out in two dimensions, and the proposed method is confirmed to work well for hard Mooney–Rivlin materials. It is also applied to 2D wall‐bounded flows involving biconcave particles, and the effects of the solid stiffness on the shape and distribution of the particles, and the overall flow rate are discussed. Copyright © 2010 John Wiley & Sons, Ltd.
On the discontinuous Galerkin computation of N‐waves focusing
Authors: Sescu Adrian , Afjeh Abdollah A. 
Published: October 2010

AbstractSonic boom focusing phenomenon can be predicted using the solution to the nonlinear Tricomi equation which is a hybrid (hyperbolic‐elliptic) second‐order partial differential equation. In this paper, the hyperbolic conservation law form is derived, which is valid in the entire domain. In this manner, the presence of two regions where the equation behaves differently (hyperbolic in the upper and elliptic in the lower half‐plane) is avoided. On the upper boundary, a new mixed boundary condition for the acoustic pressure is employed. The discretization is carried out using a discontinuous Galerkin (DG) method combined with a Runge–Kutta total‐variation diminishing scheme. The results show the accuracy of DG methods to solve problems involving sharp gradients and discontinuities. Comparisons with analytical results for the linear case, and other numerical results using classical explicit and compact finite difference schemes and weighted essentially non‐oscillatory schemes are included. Copyright © 2010 John Wiley & Sons, Ltd.
Joint testing of genotype and ancestry association in admixed families
Authors: Tang Hua , Siegmund David O. , Johnson Nicholas A. , Romieu Isabelle , London Stephanie J. 
Published: October 2010

AbstractCurrent genome‐wide association studies (GWAS) often involve populations that have experienced recent genetic admixture. Genotype data generated from these studies can be used to test for association directly, as in a non‐admixed population. As an alternative, these data can be used to infer chromosomal ancestry, and thus allow for admixture mapping. We quantify the contribution of allele‐based and ancestry‐based association testing under a family‐design, and demonstrate that the two tests can provide non‐redundant information. We propose a joint testing procedure, which efficiently integrates the two sources information. The efficiencies of the allele, ancestry and combined tests are compared in the context of a GWAS. We discuss the impact of population history and provide guidelines for future design and analysis of GWAS in admixed populations. Genet. Epidemiol. 34:783‐791, 2010. © 2010 Wiley‐Liss, Inc.
The economic impact of dementia in Europe in 2008—cost estimates from the Eurocode project
Authors: Wimo A. , Jönsson L , Gustavsson A. , McDaid D. , Ersek K. , Georges J. , Gulácsi L. , Karpati K. , Kenigsberg P. , Valtonen H. 
Published: October 2010

AbstractObjectiveCare for demented people is very resource demanding, the prevalence is increasing and there is so far no cure.Cost of illness (CoI) studies are important by identifying the distribution of costs between different payers of care. The European Union (EU) funded the European Collaboration on Dementia (Eurocode) as part of the EU's 2005 work plan of the Community public health programme. Eurocode was administered by Alzheimer Europe.The aim was to describe the economic impact of dementia in Europe in 2008.MethodsEurocode's new estimates for dementia prevalence were included in a cost model based on published European CoI papers. For countries where no CoI figures were available, imputation was used.ResultsThe total CoI of dementia in the EU27 in 2008 was estimated to be €160 billion (€22 000 per demented per year), of which 56% were costs of informal care. The corresponding costs for the whole Europe was €177 billion. In northern Europe, the direct costs are estimated to be considerabe, while the cost of informal care is the major cost component in southern Europe. The sensitivity analysis showed a range for total EU27 costs between €111 and 168 billion.ConclusionsThe estimated CoI in this study is higher than in previous studies. There are also large differences in different European regions. Notwithstanding the methodological challenges, the societal costs of dementia in Europe are very high which in turn have substantial resource impacts on the social and health care systems in Europe. Copyright © 2010 John Wiley & Sons, Ltd.
Lack of awareness of symptoms in people with dementia: the structural and functional basis
Authors: Zamboni G. , Wilcock G. 
Published: October 2010

AbstractObjectiveTo review studies investigating the brain correlates of unawareness of cognitive and behavioural symptoms in people with dementia.DesignA detailed search of the literature was conducted to include all the peer‐reviewed studies published in English aimed at identifying the structural or functional brain correspondents of unawareness in dementia patients. Their results were interpreted in relation to the methodological differences in terms of type of dementia studied, the protocol adopted to measure lack of awareness, the imaging techniques employed, the experimental designs and statistical analyses performed.ResultsEighteen studies undertaken to explore the functional and structural correlates of unawareness of cognitive symptoms in dementia were identified. Although their results showed a disparate range of brain correlates, they were mainly localized in frontal and temporo‐parietal regions.ConclusionsAlthough the anatomical correlates of unawareness of disease in dementia have not yet been exhaustively explored, understanding the correlates of unawareness may also contribute to understand the brain correlates of self‐awareness and self‐reflection. We discuss the current knowledge base and consider potential future directions for research. Copyright © 2010 John Wiley & Sons, Ltd.
Synergistic associations of depression and apolipoprotein E genotype with incidence of dementia
Authors: Kim Jae‐Min , Stewart Robert , Kim Seon‐Young , Kim Sung‐Wan , Bae Kyung‐Yeol , Yang Su‐Jin , Shin Il‐Seon , Yoon Jin‐Sang 
Published: October 2010

AbstractObjectivesA cohort study of Japanese‐American men suggested interactive effects of depression and apolipoprotein E (APOE) e4 allele on risk of incident dementia. In another sample of East Asian origin, we sought to replicate the findings and to explore individual depressive symptoms where this interaction was most evident.MethodsOf 625 Korean community elders without dementia at baseline, 518 (83%) were followed over a 2.4‐year period and were clinically assessed for incident dementia. Depression was identified by the Geriatric Mental State Schedule (GMS), and nine individual depressive symptoms relevant to DSM‐IV major depressive episode criteria were extracted. APOE genotype was ascertained. Covariates included age, gender, education, and disability.ResultsThere were synergistic interactions between depression and APOE e4 on incident dementia independent of covariates. This interaction was particularly strong for four depressive symptoms: depressed mood, worthlessness, concentration difficulty, and suicidal ideation.ConclusionsWe were able to replicate the previous study, finding that, at least in East Asian origin populations, the APOE e4 allele is a stronger predictor of incident dementia in the presence of depressive syndrome, and particular depressive symptoms. Copyright © 2010 John Wiley & Sons, Ltd.
Binding of the Rett syndrome protein, MeCP2, to methylated and unmethylated DNA and chromatin
Authors: Hansen Jeffrey C. , Ghosh Rajarshi P. , Woodcock Christopher L. 
Published: October 2010

AbstractMethylated CpG Binding Protein 2 (MeCP2) is a nuclear protein named for its ability to selectively recognize methylated DNA. Much attention has been focused on understanding MeCP2 structure and function in the context of its role in Rett syndrome, a severe neurodevelopmental disorder that afflicts one in 10,000–15,000 girls. Early studies suggested a connection between DNA methylation, MeCP2, and establishment of a repressive chromatin structure at specific gene promoters. However, it is now recognized that MeCP2 can both activate and repress specific genes depending on the context. Likewise, in the cell, MeCP2 is bound to unmethylated DNA and chromatin in addition to methylated DNA. Thus, to understand the molecular basis of MeCP2 functionality, it is necessary to unravel the complex interrelationships between MeCP2 binding to unmethylated and methylated regions of the genome. MeCP2 is unusual and interesting in that it is an intrinsically disordered protein, that is, much of its primary sequence fails to fold into secondary structure and yet is functional. The unique structure of MeCP2 is the subject of the first section of this article. We then discuss recent investigations of the in vitro binding of MeCP2 to unmethylated and methylated DNA, and the potential ramifications of this work for in vivo function. We close by focusing on mechanistic studies indicating that the binding of MeCP2 to chromatin results in compaction into local (secondary) and global (tertiary) higher order structures. MeCP2 also competes with histone H1 for nucleosomal binding sites. The recent finding that MeCP2 is found at near stoichiometric levels with nucleosomes in neuronal cells underscores the multiple modes of engagement of MeCP2 with the genome, which include the cooperative tracking of methylation density. © 2010 IUBMB IUBMB Life, 62(10): 732–738, 2010