bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cardiac and respiratory double self‐gated cine MRI in the mouse at 7 T
Authors: Hiba Bassem , Richard Nathalie , Janier Marc , Croisille Pierre 
Published: February 2006

AbstractECG‐gated cardiac MRI in the mouse is hindered by many technical difficulties in ECG signal recording inside static and variable high magnetic scanner fields. The present study proposes an alternative robust method of acquiring auto‐gated cardiac and respiratory cine images in mouse heart. In our approach, a motion synchronization signal is extracted from the echo peak MR signal of a non‐triggered radial acquisition. This signal is then used for both cardiac and respiratory retrospective gating before cine image reconstruction. Highly asymmetric echoes were acquired to achieve the radial k‐space sampling in order to avoid radial acquisition related artifacts and to increase auto‐gating robustness. In vivo experiments demonstrated the feasibility and robustness of self‐gated cine‐MRI in the mouse heart at 7T. The signal‐to‐noise and contrast‐to‐noise ratios of the self‐gated and ECG‐gated images were comparable, all parameters being equal. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Contrast behavior and relaxation effects of conventional and hyperecho‐turbo spin echo sequences at 1.5 and 3 T
Authors: Weigel Matthias , Hennig Juergen 
Published: February 2006

AbstractTo overcome specific absorption rate (SAR) limitations of spin‐echo‐based MR imaging techniques, especially at (ultra) high fields, rapid acquisition relaxation enhancement/TSE (turbo spin echo)/fast spin echo sequences in combination with constant or variable low flip angles such as hyperechoes and TRAPS (hyperTSE) have been introduced. Due to the multiple spin echo and stimulated echo pathways involved in the signal formation, the contrast behavior of such sequences depends on both T2 and T1 relaxation times. In this work, constant and various variable flip angle sequences were analyzed in a volunteer study. It is demonstrated that a single effective echo time parameter TEeff can be calculated that accurately describes the overall T2 weighted image contrast. TEeff can be determined by means of the extended phase graph concept and is practically independent of field strength. Using the described formalism, the contrast of any TSE sequence can be predicted. HyperTSE sequences are demonstrated to show a robust and well‐defined T2 contrast allowing clinical routine MRI to be performed with SAR reductions of typically at least 70%. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
A multilevel passenger screening problem for aviation security
Authors: McLay Laura A. , Jacobson Sheldon H. , Kobza John E. 
Published: February 2006

AbstractPassenger prescreening is a critical component of aviation security systems. This paper introduces the Multilevel Allocation Problem (MAP), which models the screening of passengers and baggage in a multilevel aviation security system. A passenger is screened by one of several classes, each of which corresponds to a set of procedures using security screening devices, where passengers are differentiated by their perceived risk levels. Each class is defined in terms of its fixed cost (the overhead costs), its marginal cost (the additional cost to screen a passenger), and its security level. The objective of MAP is to assign each passenger to a class such that the total security is maximized subject to passenger assignments and budget constraints. This paper shows that MAP is NP‐hard and introduces a Greedy heuristic that obtains approximate solutions to MAP that use no more than two classes. Examples are constructed using data extracted from the Official Airline Guide. Analysis of the examples suggests that fewer security classes for passenger screening may be more effective and that using passenger risk information can lead to more effective security screening strategies. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006
The Banzhaf value and communication situations
Authors: Alonso‐Meijide J.M. , Fiestras‐Janeiro M.G. 
Published: February 2006

AbstractMyerson 3 and 4 proposed and characterized a modification of the Shapley value in the context of communication situations. In this paper we propose several characterizations of the extension of the Banzhaf value proposed by Owen 7 to communication situations. In particular we characterize this value with the properties of fairness, isolation, and pairwise merging. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006
Modeling the operation of multireservoir systems using decomposition and stochastic dynamic programming
Authors: Archibald T.W. , McKinnon K.I.M. , Thomas L.C. 
Published: February 2006

AbstractStochastic dynamic programming models are attractive for multireservoir control problems because they allow non‐linear features to be incorporated and changes in hydrological conditions to be modeled as Markov processes. However, with the exception of the simplest cases, these models are computationally intractable because of the high dimension of the state and action spaces involved. This paper proposes a new method of determining an operating policy for a multireservoir control problem that uses stochastic dynamic programming, but is practical for systems with many reservoirs. Decomposition is first used to reduce the problem to a number of independent subproblems. Each subproblem is formulated as a low‐dimensional stochastic dynamic program and solved to determine the operating policy for one of the reservoirs in the system. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006
A stochastic model for burn‐in procedures in accelerated environment
Authors: Cha Ji Hwan 
Published: February 2006

AbstractBurn‐in procedure is a manufacturing technique that is intended to eliminate early failures of system or product. Burning‐in a component or system means to subject it to a period of use prior to being used in field. Generally, burn‐in is considered expensive and so the length of burn‐in is typically limited. Thus, burn‐in is most often accomplished in an accelerated environment in order to shorten the burn‐in process. A new failure rate model for an accelerated burn‐in procedure, which incorporates the accelerated ageing process induced by the accelerated environmental stress, is proposed. Under a more general assumption on the shape of failure rate function of products, which includes the traditional bathtub‐shaped failure rate function as a special case, upper bounds for optimal burn‐in time will be derived. A numerical example will also be given for illustration. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006
A precise numerical method for Rayleigh waves in a stratified half space
Authors: Gao Q. , Lin J. H. , Zhong W. X. , Howson W. P. , Williams F. W. 
Published: February 2006

AbstractThis paper presents theory and results for Rayleigh waves propagating in a transversely isotropic stratified solid resting on an elastic semi‐infinite space. It uses the precise integration method (PIM) and the extended Wittrick–Williams (W–W) algorithm. This problem can be reduced into the eigenvalue problem of ordinary differential equations (ODEs) in the frequency–wavenumber domain. The PIM used here is a precise method for solving the ODEs with two‐point boundary conditions, and the eigenvalue counting method of the extended W–W algorithm is used to ensure that all eigenvalues are found without the possibility of any being missed. Hence the theory presented in this paper is exact, in the sense that its precision is limited only by the precision of the computer used. Copyright © 2006 John Wiley & Sons, Ltd.
Convergence of a spectral projection of the Camassa‐Holm equation
Authors: Kalisch Henrik , Raynaud Xavier 
Published: February 2006

AbstractA spectral semi‐discretization of the Camassa‐Holm equation is defined. The Fourier‐Galerkin and a de‐aliased Fourier‐collocation method are proved to be spectrally convergent. The proof is supplemented with numerical explorations that illustrate the convergence rates and the use of the dealiasing method. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2006
High‐order approximation of 2D convection‐diffusion equation on hexagonal grids
Authors: Karaa Samir 
Published: February 2006

AbstractWe derive a fourth‐order finite difference scheme for the two‐dimensional convection‐diffusion equation on an hexagonal grid. The difference scheme is defined on a single regular hexagon of size h over a seven‐point stencil. Numerical experiments are conducted to verify the high accuracy of the derived scheme, and to compare it with the standard second‐order central difference scheme. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2006
An error analysis and the mesh independence principle for a nonlinear collocation problem
Authors: Aitbayev Rakhim 
Published: February 2006

AbstractA nonlinear Dirichlet boundary value problem is approximated by an orthogonal spline collocation scheme using piecewise Hermite bicubic functions. Existence, local uniqueness, and error analysis of the collocation solution and convergence of Newton's method are studied. The mesh independence principle for the collocation problem is proved and used to develop an efficient multilevel solution method. Simple techniques are applied for estimating certain discretization and iteration constants that are used in the formulation of a mesh refinement strategy and an efficient multilevel method. Several mesh refinement strategies for solving a test problem are compared numerically. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2006
Use of G‐CSF in Matched Sibling Donor Pediatric Allogeneic Transplantation: A Consensus Statement from the Children's Oncology Group (COG) Transplant Discipline Committee and Pediatric Blood and Marrow Transplant Consortium (PBMTC) Executive Committee
Authors: Grupp Stephan A. , Frangoul Haydar , Wall Donna , Pulsipher Michael A. , Levine John E. , Schultz Kirk R. 
Published: February 2006

AbstractPreliminary studies indicate that G‐CSF‐primed marrow harvesting may result in a graft with increased mononuclear cells collected, increased CD34+ stem and progenitor cell dose and a potential for more rapid engraftment. Increased cell dose plus other potential positive effects of G‐CSF priming have resulted in improved survival in non‐randomized preliminary studies. These benefits may be available without the increased risk of chronic graft versus host disease (GVHD) that is experienced with allogeneic peripheral blood stem cell (PBSC) transplant. A phase III Children's Oncology Group (COG)/Pediatric Blood and Marrow Transplant Consortium (PBMTC) trial comparing G‐CSF‐primed marrow to standard marrow has been proposed. This document reviews background studies of G‐CSF‐primed marrow and addresses benefits and risks of G‐CSF administration to normal pediatric donors. We conclude that the approach is promising and warrants further study. Risks of G‐CSF to the donor are minimal and benefits to both donor and recipient may occur. Pediatr Blood Cancer 2006,46:414–421. © 2006 Wiley‐Liss, Inc.
Metal ion permeation properties of silk fibroin/chitosan blend membranes
Authors: Du Chun‐Hui , Zhu Bao‐Ku , Chen Jian‐Yong , Xu You‐Yi 
Published: February 2006

AbstractSilk fibroin/chitosan (SF/CS) blend membranes were prepared and characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy. It was found that SF and CS were compatible in the blend membranes and that the membranes were dense without microscopic phase separation. Swelling experiments showed that the swelling ratio of the blend membranes increased with CS content and reached the highest value when CS content was 70 wt%. Experiments indicated that the permeability coefficient of K+ through the blend membrane was 2–4 times higher than that of pure CS membrane, and 10 times higher than that of pure SF membrane. The permeation rate of K+ increased linearly with CS content in the blend membrane for the lower concentration feeding solution. For different metal ions, the permeability through SF/CS blend membranes was in the sequence K+ > Ca2+ > Cd2+ > Pb2+ > Cu2+ > Ni2+. Copyright © 2006 Society of Chemical Industry
Influence of viscosity ratio on processing and morphology of thermotropic liquid crystal polymer‐reinforced poly(ethylene 2,6‐naphthalate) blends
Authors: Kim Jun Young , Kim Seong Hun 
Published: February 2006

AbstractThermotropic liquid crystal polymer (TLCP) microfibril‐reinforced poly(ethylene 2,6‐naphthalate) (PEN) composites with various intrinsic viscosities were prepared by a melt compounding method. Polymer composites consisting of bulk cheap polyester with a small amount of expensive TLCP are of interest from a commercial perspective. The TLCP acts as a nucleating agent in the TLCP/PEN composites, enhancing the crystallization of the PEN matrix through heterogeneous nucleation. The structural viscosity index of the TLCP/PEN composites was lower than that of PEN and TLCP, which was attributed to the formation of TLCP fibrillar structures with elongated fibrils in the PEN matrix. The TLCP/PEN composites with higher intrinsic viscosity than the polymer matrix contained these elongated fibrils, and had a TLCP component with a smaller average diameter, and a narrower diameter distribution than TLCP/PEN composites with lower intrinsic viscosity. The higher intrinsic viscosity of the polymer matrix, the higher shear rate and the lower viscosity ratio of TLCP to PEN can all favour TLCP fibrillation in the polymer composites. Copyright © 2006 Society of Chemical Industry
Titanium‐mediated living radical styrene polymerizations. V. Cp2TiCl‐catalyzed initiation by epoxide radical ring opening: Effect of solvents and additives
Authors: Asandei Alexandru D. , Moran Isaac W. , Saha Gobinda , Chen Yanhui 
Published: February 2006

AbstractThe effects of solvents, additives, ligands, and solvent in situ drying agents as well as catalyst and initiator concentrations have been investigated in the Cp2TiCl‐catalyzed radical polymerization of styrene initiated by epoxide radical ring opening. On the basis of the solubilization of Cp2Ti(III)Cl and the polydispersity of the resulting polymer, the solvents rank as follows: dioxane ≥ tetrahydrofuran > diethylene glycol dimethyl ether > methoxybenzene > diphenyl ether ≥ bulk > toluene ≫ pyridine > dimethylformamide > 1‐methyl‐2‐pyrrolidinone > dimethylacetamide > ethylene carbonate, acetonitrile, and trioxane. Alkoxide additives such as aluminum triisopropoxide and titanium(IV) isopropoxide are involved in alkoxide ligand exchange with the epoxide‐derived titanium alkoxide and lead to broad molecular weight distributions, whereas similarly to strongly coordinating solvents, ligands such as bipyridyl block the titanium active site and prevent the polymerization. By contrast, softer ligands such as triphenylphosphine improve the polymerization in less polar solvents such as toluene. Although mixed hydrides such as lithium tri‐tert‐butoxyaluminum hydride, sodium borohydride, and lithium aluminum hydride react with bis(cyclopentadienyl)titanium dichloride to form mixed titanium hydride species ineffective in polymerization control, simple hydrides such as lithium hydride, sodium hydride, and especially calcium hydride are particularly effective as in situ trace water scavengers in this polymerization. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2015–2026, 2006
Iron‐catalyzed radical polymerization of acrylamides in the presence of Lewis acid for simultaneous control of molecular weight and tacticity
Authors: Sugiyama Yuya , Satoh Kotaro , Kamigaito Masami , Okamoto Yoshio 
Published: February 2006

AbstractThis work is directed to the stereospecific living radical polymerization of acrylamides such as N,N‐dimethylacrylamide and N‐isopropylacrylamide with an iron complex and a Lewis acid. DMAM was polymerized with [FeCp(CO)2]2 in conjunction with an alkyl iodide [(CH3)2C(CO2Et)I] as an initiator in the presence of Y(OTf)3 in toluene/methanol (1/1) at 60 °C to be converted almost quantitatively to the polymers with controlled molecular weights and high isotacticity (m > 80%), wherein the Fe‐complex generates radical species from a covalent CI bond of the dormant species and the Lewis acid controls the stereochemistry of the polymerization via coordination with the amide groups of the polymer terminal and the monomer. A series of Lewis acids were also used for the iron(I)‐catalyzed DMAM polymerization, and Yb(OTf)3 and Yb(NTf2)3 proved effective in giving isotactic polymers without deteriorating the molecular weight control similar to Y(OTf)3. Furthermore, a slight enhancement of isospecificity was observed for the iron‐catalyzed system in comparison with the α,α‐Azobisisobutyronitrile‐initiated, when coupled with Y(OTf)3. Stereoblock polymerization of DMAM via a one‐pot reaction was also achieved by just adding the Y(OTf)3 methanol solution in the course of the polymerization to give atactic‐b‐isotactic poly(DMAM). A similar but slightly lower control in the molecular weight and tacticity was achieved in the polymerization of NIPAM with [FeCp(CO)2]2/Y(OTf)3. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2086–2098, 2006
Synthesis of comb‐like polystyrene with poly(N‐phenyl maleimide‐alt‐p‐chloromethyl styrene) as macroinitiator
Authors: Shi Yan , Fu Zhifeng , Yang Wantai 
Published: February 2006

AbstractThe copolymerization of N‐phenyl maleimide and p‐chloromethyl styrene via reversible addition–fragmentation chain transfer (RAFT) process with AIBN as initiator and 2‐(ethoxycarbonyl)prop‐2‐yl dithiobenzoate as RAFT agent produced copolymers with alternating structure, controlled molecular weights, and narrow molecular weight distributions. Using poly(N‐phenyl maleimide‐alt‐p‐chloromethyl styrene) as the macroinitiator for atom transfer radical polymerization of styrene in the presence of CuCl/2,2′‐bipyridine, well‐defined comb‐like polymers with one graft chain for every two monomer units of backbone polymer were obtained. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2069–2075, 2006
Effect of reaction conditions on the molecular weight and polydispersity of linear poly(arylene ether phosphine oxide)s prepared from an AB monomer
Authors: Kaiti Sridevi , Fossum Eric 
Published: February 2006

AbstractA thorough study of the polymerization behavior of 4‐fluoro‐4′‐hydroxytriphenyl‐phosphine oxide, 2, under nucleophilic aromatic substitution reactions has been carried out. The synthesis of 2 was achieved in excellent yields by the reaction of bis(4‐fluorophenyl)phenylphosphine oxide, 1, with one equivalent of potassium hydroxide in DMSO/water. The structure and purity of 2 were confirmed via 1H, 13C, and 31P NMR spectroscopy along with elemental analysis. Polymerization reactions of 2 in NMP or DMSO at 180 °C provided the corresponding linear poly(arylene ether phosphine oxide)s, PAEPOs, with number average molecular weights, Mn, ranging from 11,700 to 36,500 Da. All of the polymer samples were completely soluble in chloroform, tetrahydrofuran, DMSO, NMP, and DMAc. The polymerization reactions were accompanied by a competing intramolecular process that resulted in the formation of cyclic oligomeric species that were removed via a final precipitation from methanol. Analysis using 31P NMR spectroscopy and size exclusion chromatography (SEC) confirmed that the majority of the lower molecular weight cyclic species were removed via this process. The polymer samples formed tough films when chloroform solutions were slowly evaporated on a glass slide. The PAEPO samples prepared in this study exhibited excellent thermal stability with Td (5%) values between 503 and 542 in air while the glass transition temperatures ranged from 223 to 237 °C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2099–2106, 2006
Chromatic Monitoring of DC Plasma Torches: The Latest Developments
Authors: Djakov Boyan E. , Enikov Radomir , Oliver Dick H. , Hrabovsky Milan , Kopecky Vladimir 
Published: February 2006

AbstractSummary: The chromatic‐sensing technique is based on reduction of the optical spectroscopic information about an object to three signals obtained by photodetectors with different spectroscopic responsivities. Each plasma state is represented by a point of the hue, luminance, and saturation (HLS) or C1C2C3 chromaticity space. For specific operating conditions, the plasma fluctuations cause the formation of a ring around the point of S = 0, which makes the measurement of H impossible. Such a situation can be avoided by alternative tuning of the chromatic system. Systematic studies of the output/input correlation for air and water vapour/argon mixture plasmas are made. The results are presented in the form of ‘response surfaces’, which are of interest for an eventual on‐line control. This is illustrated by a ‘C2 vs. argon flow rate and jet axial co‐ordinate’ surface, which can be used to locate the correct powder injection point in a plasma spray process.Schematic diagram of the chromatic monitoring system.imageSchematic diagram of the chromatic monitoring system.
A Simple Optical Monitoring Technique for Determining the Geometrical Characteristics of a Plasma Jet
Authors: Djakov Boyan E. , Oliver Dick H. , Enikov Radomir , Vasileva Elmira 
Published: February 2006

AbstractSummary: A sensor device is proposed to evaluate the location, size, and shape of a plasma jet. It consists of a small number (e.g., six) of photodetectors arranged in a cross‐sectional plane of the jet. Tests of the technique are made by simulations based on CCD images of a plasma jet taken simultaneously from three different angles of view.Photodiode configurationimagePhotodiode configuration
Formation of Surfaces Organized on both a Micro‐ and Nanometer Scale by a Laser‐Liquid‐Solid‐Interaction Process
Authors: Pramatarova Lilyana , Pecheva Emilia , Presker Radina 
Published: February 2006

AbstractSummary: A time‐sparing method for the fabrication of structures organized on both the micro‐ and nanometer‐scale typical of nature is demonstrated by using a laser. In the applied laser‐liquid‐solid‐interaction method, a micrometer scale architecture with precisely controlled size and shape is created by laser irradiation of various surfaces, and nanostructured hydroxyapatite is subsequently grown. Since the latter is known as the major inorganic constituent of bones and teeth, the formation of such a material may have direct application in medicine, dentistry, and tissue engineering, particularly as the population ages.A schematic drawing of the laser‐liquid‐solid‐interaction method.imageA schematic drawing of the laser‐liquid‐solid‐interaction method.
1,7‐Cyclization of 1‐diazo‐2,4‐pentadiene and its heteroanalogues: DFT study
Authors: Subbotina Julia O. , Bakulev V. A. , Herges R. , Fabian W. M. F. 
Published: February 2006

Abstract1,7‐Dipolar cyclizations of 1‐diazo‐2,4‐pentadiene1aand its heteroanalogues1b,cand4cwere studied using density functional theory (DFT). Although the heteroanalogue1chas an appropriate electronic structure to allow for pseudopericyclic cyclization, natural bond order (NBO) analysis has provided evidence for the electrocyclic ring closure. Magnetic criteria (anisotropy of the induced current density [ACID], nucleus‐independent chemical shifts [NICS]) confirmed the pericyclic character of the located transition states2a,cand5c. The activation barriers for the cyclization of 1‐diazo‐2,4‐pentadiene1aand its aza analogues1c,4care 3.3, 8.2, and 12.3 kcal/mol at the B3LYP/6‐31G(d) level, respectively. The higher barrier of the1c→3cand4c→3creactions compared with1a→3ais in line with the Hammond postulate. The out‐of‐plane distorted geometry of the cyclic product is an additional factor arguing against a pseudopericyclic mechanism. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006