bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coherence regularization for SENSE reconstruction with a nonlocal operator (CORNOL)
Authors: Fang Sheng , Ying Kui , Zhao Li , Cheng Jianping 
Published: August 2010

AbstractThe sensitivity encoding (SENSE) reconstruction reconstruction of parallel imaging can suffer from amplified noise at high reduction factors due to the ill‐conditioned system matrix. Regularization alleviates this problem by imposing priors on the reconstructed image. These priors typically introduce both intrastructure smoothness and interstructure smoothness. The former mainly reduces noise, while the latter can also decrease intensity changes between different structures and cause structure loss. In this study, coherence regularization was proposed to impose only intrastructure smoothness in order to enhance the preservation of the image structure. Its energy functional was formed by examining the connection between regularization and the diffusion equation of adaptive image filtering. The coherence regularization extracts image structure information directly from the noisy data by adapting diffusion equation–related image‐filtering methods. In this study, a nonlocal operator derived from the nonlocal mean filter was used for structure detection. Based on this structure information, only intrastructure intensity changes are penalized while the interstructure intensity changes are preserved. Both phantom simulation and in vivo experiments demonstrate that the coherence regularization would be able to effectively suppress noise in SENSE reconstruction at high reduction factors while suffering from much less image degradation, compared to Tikhonov and total variation methods. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
The one‐warehouse multiretailer problem with an order‐up‐to level inventory policy
Authors: Solyalı Og̀uz , Süral Haldun , Denizel Meltem 
Published: August 2010

AbstractWe consider a two‐level system in which a warehouse manages the inventories of multiple retailers. Each retailer employs an order‐up‐to level inventory policy over T periods and faces an external demand which is dynamic and known. A retailer's inventory should be raised to its maximum limit when replenished. The problem is to jointly decide on replenishment times and quantities of warehouse and retailers so as to minimize the total costs in the system. Unlike the case in the single level lot‐sizing problem, we cannot assume that the initial inventory will be zero without loss of generality. We propose a strong mixed integer program formulation for the problem with zero and nonzero initial inventories at the warehouse. The strong formulation for the zero initial inventory case has only T binary variables and represents the convex hull of the feasible region of the problem when there is only one retailer. Computational results with a state‐of‐the art solver reveal that our formulations are very effective in solving large‐size instances to optimality. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010
Order within disorder: Aggrecan chondroitin sulphate‐attachment region provides new structural insights into protein sequences classified as disordered
Authors: Jowitt Thomas A. , Murdoch Alan D. , Baldock Clair , Berry Richard , Day Joanna M. , Hardingham Timothy E. 
Published: August 2010

AbstractStructural investigation of proteins containing large stretches of sequences without predicted secondary structure is the focus of much increased attention. Here, we have produced an unglycosylated 30 kDa peptide from the chondroitin sulphate (CS)‐attachment region of human aggrecan (CS‐peptide), which was predicted to be intrinsically disordered and compared its structure with the adjacent aggrecan G3 domain. Biophysical analyses, including analytical ultracentrifugation, light scattering, and circular dichroism showed that the CS‐peptide had an elongated and stiffened conformation in contrast to the globular G3 domain. The results suggested that it contained significant secondary structure, which was sensitive to urea, and we propose that the CS‐peptide forms an elongated wormlike molecule based on a dynamic range of energetically equivalent secondary structures stabilized by hydrogen bonds. The dimensions of the structure predicted from small‐angle X‐ray scattering analysis were compatible with EM images of fully glycosylated aggrecan and a partly glycosylated aggrecan CS2‐G3 construct. The semiordered structure identified in CS‐peptide was not predicted by common structural algorithms and identified a potentially distinct class of semiordered structure within sequences currently identified as disordered. Sequence comparisons suggested some evidence for comparable structures in proteins encoded by other genes (PRG4, MUC5B, and CBP). The function of these semiordered sequences may serve to spatially position attached folded modules and/or to present polypeptides for modification, such as glycosylation, and to provide templates for the multiple pleiotropic interactions proposed for disordered proteins. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Phase transition, microstructure and electric‐field‐induced large strain in Bi0.5(Na0.85K0.15)0.5TiO3–BiAlO3 lead‐free piezoelectric ceramics
Authors: Ullah Aman , Ahn Chang Won , Kim Ill Won 
Published: August 2010

AbstractLead‐free (1 − x)(Bi0.5(Na0.85K0.15)0.5TiO3)‐xBiAlO3 (abbreviated as BNKT15‐BA, x = 0, 0.025, 0.050, 0.075, 0.100) piezoelectric ceramics were synthesized by a conventional solid‐state reaction method. The phase‐transition behavior in BNKT15‐BA ceramics with respect to changes in composition were investigated using X‐ray diffraction analysis, dielectric and ferroelectric characterizations, and electric‐field‐induced strain. The results of X‐ray diffraction revealed that a pure perovskite phase was formed for x ≤ 0.050. A phase transition from the coexistence of rhombohedral and tetragonal to a pseudocubic phase was observed at x = 0.050. The dielectric constant continuously decreased with increasing BA content, and the depolarization temperature (Td) was shifted towards lower temperature. The polarization and strain hysteresis loops indicate that the ferroelectric order of BNKT15 ceramics is disrupted significantly with the addition of BA. The destabilization of ferroelectric order is accompanied by an enhancement of bipolar and unipolar strains, and a large electric‐field‐induced strain (S = 0.21%) and a normalized strain ($d_{33}^{*} $ = Smax/Emax = 276 pm/V) were obtained at x = 0.050. These results suggested that the BNKT15‐BA system can be employed in lead‐free electromechanical devices.
Characterization of Au‐metal nanoparticle‐hybridized poly (3,4‐ethylenedioxythiophene) films for electrochromic devices
Authors: Lee Jong Seok , Choi Yong‐June , Wang Seok‐Joo , Park Hyung‐Ho , Pyun Jae Chul 
Published: August 2010

AbstractIn order to enhance the electrochromic properties of poly (3,4‐ethylenedioxythiophene) (PEDOT), Au/PEDOT nano‐hybrid thin films were prepared from a Au nanoparticle (Au NP), 3,4‐ethylenedioxythiophene (EDOT), iron p‐toluenesulfonate and imidazole mixture. The incorporation of Au NPs slightly affected the surface roughness of PEDOT films but had an important impact on the conjugation length and packing density of PEDOT due to the physical volume effect. An enhancement in the electrochromic properties of PEDOT was obtained, in particular, a 50% reduction in the switching speed of PEDOT with a blue shift of the maximum absorption peak in the ultra violet‐visible spectroscopic analysis.
The ECMWF re‐analysis for the AMMA observational campaign
Authors: Agustí‐Panareda Anna , Beljaars Anton , Ahlgrimm Maike , Balsamo Gianpaolo , Bock Olivier , Forbes Richard , Ghelli Anna , Guichard Françoise , Köhler Martin , Meynadier Remi , Morcrette Jean‐Jacques 
Published: August 2010

AbstractDuring the 2006 African Monsoon Multidisciplinary Analysis (AMMA) field experiment, an unprecedented number of soundings were performed in West Africa. However, due to technical problems many of these soundings did not reach the Global Telecommunication System and therefore they could not be included in the operational numerical weather prediction (NWP) analyses. This issue, together with the realization that there was a significant bias in the radiosonde humidity, led to the conclusion that a re‐analysis effort was necessary. This re‐analysis was performed at the European Centre for Medium‐Range Weather Forecasts (ECMWF) spanning the wet monsoon season of 2006 from May–September. The key features of the ECMWF AMMA re‐analysis are presented, including the use of a newer model version with improved physics, all the AMMA radiosonde data available from the AMMA database and a new radiosonde humidity bias‐correction scheme. Data‐impact experiments show that there is a benefit from these observations, but also highlight large model physics biases over the Sahel that cause a short‐lived impact of the observations on the model forecast. The AMMA re‐analysis is compared with independent observations to investigate the biases in the different parts of the physics. In the framework of the AMMA project, a hybrid dataset was developed to provide a best estimate of the different terms of the water cycle. This hybrid dataset is used to evaluate the improvement achieved from the use of extra AMMA observations and of a radiosonde humidity bias‐correction scheme in the water cycle of the West African monsoon. Finally, future model developments that offer promising improvements in the water cycle are discussed. Copyright © 2010 Royal Meteorological Society
Can 4D‐Var use dynamical information from targeted observations of a baroclinic structure?
Authors: Irvine E. A. , Gray S. L. , Methven J. 
Published: August 2010

AbstractTargeted observations are generally taken in regions of high baroclinicity, but often show little impact. One plausible explanation is that important dynamical information, such as upshear tilt, is not extracted from the targeted observations by the data assimilation scheme and used to correct initial condition error. This is investigated by generating pseudo targeted observations which contain a singular vector (SV) structure that is not present in the background field or routine observations, i.e. assuming that the background has an initial condition error with tilted growing structure. Experiments were performed for a single case‐study with varying numbers of pseudo targeted observations. These were assimilated by the Met Office four‐dimensional variational (4D‐Var) data assimilation scheme, which uses a 6 h window for observations and background‐error covariances calculated using the National Meteorological Centre (NMC) method. The forecasts were run using the operational Met Office Unified Model on a 24 km grid. The results presented clearly demonstrate that a 6 h window 4D‐Var system is capable of extracting baroclinic information from a limited set of observations and using it to correct initial condition error. To capture the SV structure well (projection of 0.72 in total energy), 50 sondes over an area of 1×106 km2 were required. When the SV was represented by only eight sondes along an example targeting flight track covering a smaller area, the projection onto the SV structure was lower; the resulting forecast perturbations showed an SV structure with increased tilt and reduced initial energy. The total energy contained in the perturbations decreased as the SV structure was less well described by the set of observations (i.e. as fewer pseudo observations were assimilated). The assimilated perturbation had lower energy than the SV unless the pseudo observations were assimilated with the dropsonde observation errors halved from operational values. Copyright © 2010 Royal Meteorological Society
Structure, stability, and dynamics of hydrogen polyoxides
Authors: Martins‐Costa Marilia , Anglada Josep M. , Ruiz‐López Manuel F. 
Published: August 2010

AbstractHydrogen polyoxides H2On have been theoretically studied in gas phase and in aqueous solution. Structures up to n = 4 have been detected experimentally. Larger systems are speculative till now but previous calculations predicted stable structures. Minimum energy geometries and formation enthalpies for n = 3–10 have been calculated in gas phase using high‐level ab initio calculations that include DFT, QCISD, and CCSD(T) methods. Formation enthalpies are negative for n < 5, close to zero for n = 5, and positive for n > 5. They go up by ∼12–16 kcal/mol per O atom although the increase is not regular; it presents an oscillatory behavior that is clearly connected with odd/even effects reported for OO bond lengths. Computations in aqueous solution focus on free energies of solvation, solute–solvent hydrogen bonds strength, and solvent effects on polyoxide structure. We use two solvent models. A dielectric continuum implicit model is used to estimate free energies of solvation at an affordable cost. An explicit model is then used combining a QM/MM description of the solution and molecular dynamics (MD) simulations for polyoxides n = 3–6. The solute is described at the DFT level whereas solvent molecules are treated with an empirical force field. The analysis of the solute dynamics in solution shows that the systems are very good proton donors but poor proton acceptors. The structure with n = 5 exhibits a particular behavior that seems to be related with its larger statistical probability of forming intramolecular hydrogen bonds. Most bonds are lengthened in solution, especially the polar HO bonds and the inner OO bonds. Remarkably, the amplitude of OO bond length fluctuations has been shown to depend primarily on its position along the chain, that is, the distance with respect to the terminal HO bond, and less on chain length. For n = 6, the central OO bond fluctuates between 1.2 and 1.9 Å. Chains beyond n = 6 should be extremely labile since fluctuations of the central OO bonds should be even larger. Hence, if formed, the corresponding lifetimes should be extremely short. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Electronic states of hydrogen atom in tetrahedral and similar polyhedral cavities
Authors: Pupyshev Vladimir I. 
Published: August 2010

AbstractElectronic states of an atomic particle situated inside an impenetrable cavity of a simple polyhedral form are studied. The numerical method used here for calculations and its theoretical backgrounds are presented. Numerical estimates for the energy levels of a hydrogen atom inside impenetrable cavities of a tetrahedral, cubic, or more complex shape corresponding to truncated polyhedrons are described. The state ordering of the lowest electronic states for confined hydrogen atom, associated with 1s–3d‐states of a free system, is studied with special attention to the role of the vertexes in tetrahedral cavities. Some details of the state ordering for tetrahedral, octahedral, cubic, and some other polyhedral cavities are analyzed. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
On the shape dependence of cluster (hyper)polarizabilities. A combined ab initio and DFT study on large fullerene–like gallium arsenide semiconductor clusters
Authors: Karamanis Panaghiotis , Pouchan Claude 
Published: August 2010

AbstractThe effect of the cluster shape on the magnitudes of the static dipole (hyper)polarizabilities of large gallium arsenic clusters built from 72 atoms is presented and discussed. Also, the performance of conventional and long range corrected density functionals is assessed on the prediction of the static electric dipole hyperpolarizabilities. The reported results obtained at the Hartree‐Fock, (LC‐) BLYP, (LC‐) BPW91, (CAM)‐B3LYP, and WB97XD levels of theory demonstrate that the cluster shape not only dominates the magnitude of the second hyperpolarizabilities of clusters but also affects dramatically the performance of the density functional theory functionals used. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Experimental analysis of the effective components of problem‐based learning
Authors: Pease María A. , Kuhn Deanna 
Published: August 2010

AbstractProblem‐based learning (PBL) is widely endorsed as a desirable learning method, particularly in science. Especially in light of the method's heavy demand on resources, evidence‐based practice is called for. Rigorous studies of the method's effectiveness, however, are scarce. In Study 1, college students enrolled in an elementary physics course participated in 7 hours of instruction on two concepts, one (electromagnetic field) via a PBL method and the other (gravitational field) via a lecture/discussion method. A comparison class enrolled in the same course with the same instructor underwent the identical experience except that matching of concept and method was reversed. Multiple assessments over time showed superior mastery of the concept learned via PBL for both groups. In Study 2, using a subtractive method, we further investigated the role of specific components of the PBL method by comparing a group who worked individually using a PBL method to one who participated in the typical collaborative form of PBL. Rather than the social component typically associated with PBL, the effective component of the method appears to be the focus on engagement with a problem. © 2010 Wiley Periodicals, Inc. Sci Ed 95: 57–86, 2010.
Authenticated key exchange protocol with enhanced freshness properties
Authors: Huang Hai , Cao Zhenfu 
Published: August 2010

AbstractThis paper investigates the security model for authenticated key exchange protocols. We further enhance the enhanced Canetti‐Krawczyk (eCK) model by introducing a notion called strong key compromise impersonation (SKCI) resilience which is first identified in this paper. SKCI resilience guarantees that the adversary cannot masquerade as another party B to communicate with party A even if the static private key and the ephemeral private key of party A are compromised. We point out that the three‐pass authenticated key exchange protocol generically transformed from the two‐pass one secure in the eCK model cannot resist the SKCI attack. Finally, we introduce a new authenticated key exchange protocol SIG‐DH+ and prove that it satisfies our new definition. Copyright © 2010 John Wiley & Sons, Ltd.
Bio‐creep in non‐inferiority clinical trials
Authors: Everson‐Stewart Siobhan , Emerson Scott S. 
Published: August 2010

AbstractAfter a non‐inferiority clinical trial, a new therapy may be accepted as effective, even if its treatment effect is slightly smaller than the current standard. It is therefore possible that, after a series of trials where the new therapy is slightly worse than the preceding drugs, an ineffective or harmful therapy might be incorrectly declared efficacious; this is known as ‘bio‐creep’. Several factors may influence the rate at which bio‐creep occurs, including the distribution of the effects of the new agents being tested and how that changes over time, the choice of active comparator, the method used to account for the variability of the estimate of the effect of the active comparator, and changes in the effect of the active comparator from one trial to the next (violations of the constancy assumption). We performed a simulation study to examine which of these factors might lead to bio‐creep and found that bio‐creep was rare, except when the constancy assumption was violated. Copyright © 2010 John Wiley & Sons, Ltd.
Cement‐related particles interact with proinflammatory IL‐8 chemokine from human primary oropharyngeal mucosa cells and human epithelial lung cancer cell line A549
Authors: Bauer Mario , Gräbsch Carolin , Gminski Richard , Ollmann Ariane I.H. , Borm Paul , Dietz Andreas , Herbarth Olf , Wichmann Gunnar 
Published: August 2010

AbstractEpidemiological studies have shown that respirable exposure to emitted cement particulate matter is associated with adverse health risk for human. The underlying mechanisms, however, are poorly understood. To examine the effect of cement, nine blinded cement‐related particulates (<10 μm) were assessed with regard to their induction of the proinflammatory cytokines IL‐6 and IL‐8 in human primary epithelial cells (pEC) from oropharyngeal mucosa as well as from nonsmall‐cell lung carcinoma (non‐SCLC) cells A549. It was demonstrated that the cement specimens did not act cytotoxic as assessed by the lactate dehydrogenase (LDH) assay. The basal and IL‐1β‐induced IL‐8 expression was suppressed, in contrast to an unchanged IL‐6. At the transcript level the basal and induced IL‐6 and IL‐8 gene expression was not influenced by cement dust. To discover the mechanism by which cement influenced the IL‐8 expression the following experiments were performed. Submerse exposure experiments have shown that the release of IL‐8 was suppressed by cement dust. Furthermore, the incubation of IL‐8 with cement‐related specimens under cell‐free condition led to a loss of immunoreactive IL‐8. An immunological masking of IL‐8 by free soluble components of respiratory epithelial cells was excluded. Thus, the decrease of IL‐8 protein content after cement exposure seems to be a result of the adsorption of IL‐8 protein to cement particles and the inhibition of IL‐8 release. In conclusion, due to absent cytotoxic and inflammatory effects of cement‐related specimens in both human pEC and A549 cell models it remains open how cement exposure may lead to the respiratory adverse effects in humans. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
Comment on “Free convective flow between vertical porous plates with periodic heat input” by B. K. Jha and A. O. Ajibade, ZAMM 90, 185–193 (2010)
Authors: Magyari E. 
Published: August 2010

AbstractIn a recent paper by B. K. Jha and A. O. Ajibade (ZAMM 90, 185–193 2010) the title problem for the fully developed flow regime was investigated and exact analytical solutions for the velocity and temperature fields were reported. However, when the Prandtl number equals unity, some coefficients become singular and thus the velocity solution of Jha and Ajibade cannot be evaluated by a direct substitution of Pr = 1. The main goal of the present note is (i) to show how the singularities can be removed, (ii) to give the corresponding nonsingular velocity solutions in an explicit form, and (iii) to discuss the mathematical and physical origin of this kind of singularity in the fluid and point mechanical problems.
Real‐Time Ultrasound‐Aided Central Vein Cannulation Failure Rate: Establishing a Benchmark
Authors: Requarth Jay A. 
Published: August 2010

AbstractBackgroundThe use of real‐time two‐dimensional B‐mode ultrasound (RTUS)‐aided central venous access device (CVAD) insertion has been recommended by health‐care agencies, but a realistic failure rate for bedside attempts is unknown.MethodsThe failure rate of RTUS‐aided CVAD insertion is estimated using data from adult inpatients and outpatients referred to a tertiary referral radiology department for a new CVAD insertion during the 2.5‐year period ending February 29, 2008. Cannulation failure, complications, and additional fluoroscopic interventions per central vein cannulation attempt and per patient encounter were retrospectively collected and evaluated.ResultsOf the 2456 consecutive patient encounters, the index central vein cannulation failure rate using only RTUS and fluoroscopy was 4.8%; ultimate failure rate was 0.3%. The procedural mortality rate was 0.04%. If the index upper‐body central vein cannulation failed, an ipsilateral upper‐body attempt through a different central vein failed in 63.6%, whereas a contralateral upper‐body attempt failed in 26.7% (p = 0.11) and a common femoral vein attempt failed in 11.5% (p = 0.0039).ConclusionsThe minimum bedside failure rate of RTUS‐aided CVAD insertion is 4.8% for the index central vein cannulated. The ultimate failure rate of 0.3% and the mortality rate of 0.04% are due to RTUS, fluoroscopy, and the additional equipment available in an IR suite. If the upper‐body index central vein cannulation fails, cannulation of the common femoral vein is more likely to succeed than additional attempts in other ipsilateral upper‐body central veins.