bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological and Physical Properties of Triblock Copolymers of Methyl Methacrylate and 2‐Ethylhexyl Methacrylate
Authors: Eslami Hormoz , Zhu Shiping 
Published: August 2006

AbstractSummary: Triblock copolymers of methyl methacrylate (MMA) and 2‐ethylhexyl methacrylate (EHMA) [that is, poly(MMA–EHMA–MMA)] were prepared by an emulsion atom‐transfer radical polymerization. The relationships of their structural, morphological, and physical properties were investigated. The latex particles had core‐shell morphologies and the block copolymers experienced phase separation. Small latex particles with a low number of cores could deform and wet silicon‐wafer surfaces, but the deformation of large latex particles was restricted by the internal two‐phase morphology of the particles. Latex casting produced continuous pinhole‐free films, in which hard poly(MMA) (PMMA) cores of different latex particles merged and provided interparticle connections. The morphology of solution‐cast films depended on block composition, solvent type, and film thickness. For all the prepared polymer samples, thick films cast in toluene had poly(EHMA) (PEHMA) materials at air surface, whereas those cast in tetrahydrofuran had a sponge‐like PMMA surface structure. Thin toluene‐cast films from P(MMA–EHMA–MMA) with the block degrees of polymerization ($\overline {DP}$) 200–930–200 showed spherical PMMA domains and those from 380–930–380 yielded a protruded worm‐like PMMA structure. The copolymer materials were coated on a glass surface for peeling tests. The films gave good hot‐melt adhesion properties when the $\overline {DP}$ of the PEHMA block was over 600. The peeling strength depended on the lengths of both PEHMA and PMMA blocks. The P(MMA–EHMA–MMA) sample with $\overline {DP} {\rm s}$ of 310–930–310 yielded the highest peeling strength of 7.4 kgf · inch−1. The developed material is demonstrated to be a good candidate for a solvent‐free, hot‐melt, pressure‐sensitive adhesives for special‐purpose applications such as medical tapes and labels.
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Effect of Bio‐Scavengers on the Curing Behavior and Bonding Properties of Melamine‐Formaldehyde Resins
Authors: Kim Sumin , Kim Hyun‐Joong , Kim Hee‐Soo , Lee Hwa Hyoung 
Published: August 2006

AbstractSummary: The effects of bio‐scavengers on the formaldehyde emission, bonding strength, curing behavior, and thermal decomposition properties of MF resins for engineered flooring and adhesion for wood were investigated. Four varieties of bio‐scavengers, tannin powder, wheat flour, rice husk flour, and charcoal, were added to MF resin at 5 wt.‐%. To determine formaldehyde emission and bonding strength, we manufactured engineered floorings. MF‐charcoal was most effective in reducing formaldehyde emission because of its porous nature, but its bonding strength was decreased. Tannin powder and wheat flour, which contain more hydroxyl groups, showed higher bonding strength and curing degree than pure MF resin did. Although the hydroxyl groups of the bio‐scavengers were effective in reducing formaldehyde emission and improve bonding strength and curing degree, rice husk flour and charcoal behaved like inorganic substances, thereby disturbing the adhesion between MF resin and wood and thus reducing the bonding strength. In thermogravimetric analysis, MF‐tannin showed the highest thermal stability in the low‐temperature range from 100 to 300 °C.Storage modulus (E′) of MF resin with various bio‐scavengers at a heating rate of 10 °C · min−1.magnified imageStorage modulus (E′) of MF resin with various bio‐scavengers at a heating rate of 10 °C · min−1.
MP‐SAGE: A new MP‐RAGE sequence with enhanced SNR and CNR for brain imaging utilizing square‐spiral phase encoding and variable flip angles
Authors: Stöcker Tony , Shah N. Jon 
Published: August 2006

AbstractThe magnetization‐prepared rapid gradient‐echo (MP‐RAGE) sequence is well known and widely used for high‐resolution, structural brain MRI. Here we present a new version, termed magnetization‐prepared spiral acquisition gradient‐echo (MP‐SAGE), that employs interleaved square‐spiral phase‐encoding (PE) to take advantage of the 3D nature of the sequence. Resolution loss caused by point‐spread function (PSF) blurring is circumvented by the use of variable flip angle (VFA) radiofrequency (RF) pulses. The pulse train is calculated by means of an accurate new signal evolution theory that is derived from the extended phase graph (EPG) description. Phantom results show excellent agreement between theory and experiment for substances with relaxation times similar to those of human brain tissue. Both phantom and in vivo results show a strong enhancement of SNR and CNR compared to the standard MP‐RAGE in high‐resolution MRI. The benefits for brain tissue segmentation using images obtained with MP‐SAGE are shown. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Quantification of the pulse wave velocity of the descending aorta using axial velocity profiles from phase‐contrast magnetic resonance imaging
Authors: Yu Hsi‐Yu , Peng Hsu‐Hsia , Wang Jaw‐Lin , Wen Chih‐Yung , Tseng Wen‐Yih Isaac 
Published: August 2006

AbstractThe pulse wave velocity (PWV) of aortic blood flow is considered a surrogate for aortic compliance. A new method using phase‐contrast (PC)‐MRI is presented whereby the spatial and temporal profiles of axial velocity along the descending aorta can be analyzed. Seventeen young healthy volunteers (the YH group), six older healthy volunteers (the OH group), and six patients with coronary artery disease (the CAD group) were studied. PC‐MRI covering the whole descending aorta was acquired, with velocity gradients encoding the in‐plane velocity. From the corrected axial flow velocity profiles, PWV was determined from the slope of an intersecting line between the presystolic and early systolic phases. Furthermore, the aortic elastic modulus (Ep) was derived from the ratio of the brachial pulse pressure to the strain of the aortic diameter. The PWV increased from YH to OH to CAD (541 ± 94, 808 ± 184, 1121 ± 218 cm/s, respectively; P = 0.015 between YH and OH; P = 0.023 between OH and CAD). There was a high correlation between PWV and Ep (r = 0.861, P < 0.001). Multivariate analysis showed that age and CAD were independent risk factors for an increase in the PWV. Compared to existing methods, our method requires fewer assumptions and provides a more intuitive and objective way to estimate the PWV. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Numerical simulation of substation grounding grids buried in both horizontal and vertical multilayer earth model
Authors: Li Zhong‐Xin , Fan Jian‐Bin , Chen Wei‐Jiang 
Published: August 2006

AbstractIn the simulation of quasi‐static electromagnetic fields produced by a point source located in both horizontal and vertical multilayer media, the conventional image method requires an infinite number of images to get an accurate solution, while the method of quasi‐static complex images needs only a few ones. Based on the method of quasi‐static complex images, the closed form of Green's function of a point source in both horizontal and vertical multilayer earth model is derived through matrix pencil (MP) approach. The fast convergent Galerkin's type of boundary element method (BEM) is taken to simulate and analyse a grounding system including floating electrode with any complicated structure, which can be located anywhere in horizontal or vertical multilayer earth model. Copyright © 2006 John Wiley & Sons, Ltd.
A second‐order homogenization procedure for multi‐scale analysis based on micropolar kinematics
Authors: Larsson Ragnar , Diebels Stefan 
Published: August 2006

AbstractThe paper presents a higher order homogenization scheme based on non‐linear micropolar kinematics representing the macroscopic variation within a representative volume element (RVE) of the material. On the microstructural level the micro–macro kinematical coupling is introduced as a second‐order Taylor series expansion of the macro displacement field, and the microstructural displacement variation is gathered in a fluctuation term. This approach relates strongly to second gradient continuum formulations, presented by, e.g. Kouznetsova et al. (Int. J. Numer. Meth. Engng 2002; 54:1235–1260), thus establishing a link between second gradient and micropolar theories. The major difference of the present approach as compared to second gradient formulations is that an additional constraint is placed on the higher order deformation gradient in terms of the micropolar stretch. The driving vehicle for the derivation of the homogenized macroscopic stress measures is the Hill–Mandel condition, postulating the equivalence of microscopic and macroscopic (homogenized) virtual work. Thereby, the resulting homogenization procedure yields not only a stress tensor, conjugated to the micropolar stretch tensor, but also the couple stress tensor, conjugated to the micropolar curvature tensor. The paper is concluded by a couple of numerical examples demonstrating the size effects imposed by the homogenization of stresses based on the micropolar kinematics. Copyright © 2006 John Wiley & Sons, Ltd.
A structural damage identification method based on genetic algorithm and vibrational data
Authors: Borges Carlos C. H. , Barbosa Helio J. C. , Lemonge Afonso C. C. 
Published: August 2006

AbstractThe problem of damage identification in framed structures using vibrational data is considered. The identification problem is modelled as an optimization task and the use of measured natural frequencies as well as modeshape information in the construction of objective functions is discussed. In a first attempt, a standard genetic algorithm is shown to be ineffective in obtaining the correct damage distribution in test problems. Using domain knowledge, modifications are introduced in the coding process, in the initial population generation, in the fitness function, and in the genetic operators, leading to a promising tool to solve this class of problems. Synthetic problems, with the addition of noise in the simulated measured data associated with the damaged structure, are analysed in order to assess the capability of the proposed technique. Copyright © 2006 John Wiley & Sons, Ltd.
Finite element code for impact collapse problems of framed structures
Authors: Lynn Kyaw Myo , Isobe Daigoro 
Published: August 2006

AbstractThe objective of this study is to develop a dynamic finite element code that can effectively cope with strong non‐linearities and discontinuities common in impact collapse problems, and whose calculation cost is sufficiently low to enable dynamic analyses of full‐model large‐scale structures. The adaptively shifted integration (ASI) technique is modified into the ASI‐Gauss technique to further reduce calculation cost. Algorithms considering member fractures and elemental contact are also presented. Impact collapse analysis is conducted to simulate the aircraft impact with the World Trade Center South Tower (WTC2), and the analytical results showed good agreement with the observed data. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis of contact‐aided compliant mechanisms for non‐smooth path generation
Authors: Mankame N. D. , Ananthasuresh G. K. 
Published: August 2006

AbstractTopology optimization is used in this paper for the systematic synthesis of contact‐aided compliant mechanisms that trace prescribed, non‐smooth paths in response to a single, monotonically increasing input force. Intermittent contact interactions that enable these mechanisms to exhibit non‐smooth responses also lead to algorithmic difficulties when the techniques from the synthesis of ordinary compliant mechanisms are used to design contact‐aided compliant mechanisms. A sequential optimization approach based on a regularized normal contact model for large displacements is used in this work to circumvent these difficulties and to enable the use of computationally efficient, gradient‐based optimization methods. We use an objective function based on Fourier shape descriptors, which allows the designer to emphasize different aspects of the design intent (such as the shape, the size and the orientation of the output path) separately. A variable‐stiffness input spring is used to allow the synthesis procedure to choose the appropriate magnitude of the input force. An arc‐length finite element solver and heuristic measures that guard against local and global instabilities add to the robustness of the synthesis procedure as demonstrated by the two design examples presented in this paper. Copyright © 2006 John Wiley & Sons, Ltd.
Estimating the critical time‐step in explicit dynamics using the Lanczos method
Authors: Koteras J. R. , Lehoucq R. B. 
Published: August 2006

AbstractThe goal of our paper is to demonstrate the cost‐effective use of the Lanczos method for estimating the critical time step in an explicit, transient dynamics code. The Lanczos method can provide a significantly larger estimate for the critical time‐step than an element‐based method (the typical scheme). However, the Lanczos method represents a more expensive method for calculating a critical time‐step than element‐based methods. Our paper shows how the additional cost of the Lanczos method can be amortized over a number of time steps and lead to an overall decrease in run‐time for an explicit, transient dynamics code. We present an adaptive hybrid scheme that synthesizes the Lanczos‐based and element‐based estimates and allows us to run near the critical time‐step estimate provided by the Lanczos method. Copyright © 2006 John Wiley & Sons, Ltd.
Incremental‐secant modulus iteration scheme and stress recovery for simulating cracking process in quasi‐brittle materials using XFEM
Authors: Xiao Q. Z. , Karihaloo B. L. , Liu X. Y. 
Published: August 2006

AbstractIn this paper, an incremental‐secant modulus iteration scheme using the extended/generalized finite element method (XFEM) is proposed for the simulation of cracking process in quasi‐brittle materials described by cohesive crack models whose softening law is composed of linear segments. The leading term of the displacement asymptotic field at the tip of a cohesive crack (which ensures a displacement discontinuity normal to the cohesive crack face) is used as the enrichment function in the XFEM. The opening component of the same field is also used as the initial guess opening profile of a newly extended cohesive segment in the simulation of cohesive crack propagation. A statically admissible stress recovery (SAR) technique is extended to cohesive cracks with special treatment of non‐homogeneous boundary tractions. The application of locally normalized co‐ordinates to eliminate possible ill‐conditioning of SAR, and the influence of different weight functions on SAR are also studied. Several mode I cracking problems in quasi‐brittle materials with linear and bilinear softening laws are analysed to demonstrate the usefulness of the proposed scheme, as well as the characteristics of global responses and local fields obtained numerically by the XFEM. Copyright © 2006 John Wiley & Sons, Ltd.
Shear correction for Mindlin type plate and shell elements
Authors: Liu Yu , Soh Chee‐Kiong 
Published: August 2006

AbstractIn this paper, two shear correction methods, which can guarantee good accuracy, suitable for different materials and easy to implement, are proposed for the first‐order theory based plate and shell elements. The general variational principles based on the thermodynamic potentials are first derived, to provide a uniform frame for the different material non‐linearity. Then, the two shear correction methods are derived from the obtained general variational principles using the assumed strain and assumed stress methods, respectively. The shear correction factors (SCF) for homogeneous elastic materials are evaluated using the two methods, and the same result of 0.8 is obtained. The proposed shear correction method is then applied to an elastic‐linear hardening plastic deep beam for verification, and the conformable result is obtained as compared with the plane strain result. Copyright © 2006 John Wiley & Sons, Ltd.
Reporting of adverse drug reactions: predictors of under‐reporting in Malaysia
Authors: Aziz Zoriah , Siang Tan Ching , Badarudin Nurul Suhaida 
Published: August 2006

AbstractBackgroundMalaysia like many other countries worldwide uses spontaneous reporting systems as a mean of collecting data on suspected adverse drug reaction (ADR). However, compared to other countries, which use the system, the reporting rate in Malaysia is very low. Why some physicians do not report ADRs is not well understood.ObjectiveTo identify factors, which would predict physicians' failure to send ADR reports.Design and SettingFace‐to‐face interview using a structured questionnaire involving physicians working at the University of Malaya Medical Centre, Malaysia.ResultsAbout a third of the physicians in the Centre participated. Sixty‐five of the 415 approached refused to participate. A high proportion of the respondents (81.4%) indicated that they had suspected an ADR but did not report it, while about 40% of the respondents were not aware of the existence of the national reporting system in Malaysia. Logistic regression modelling identified the variable ‘ADR considered to be too trivial or too well known to report’ as the strongest predictor of not reporting, followed by physicians' category and uncertainty that the reaction had been definitely caused by a drug.ConclusionImportant predictor variables, which limit physicians from reporting ADR in Malaysia, were related to uncertainty of types of reaction to report, lack of awareness about the existence, function and purpose of national ADR reporting. The findings could be useful for planning strategies to improve the reporting rate. Copyright © 2006 John Wiley & Sons, Ltd.
Proteome analysis of B‐cell maturation
Authors: Salonen Johanna M. , Valmu Leena , Rönnholm Gunilla , Kalkkinen Nisse , Vihinen Mauno 
Published: August 2006

AbstractProteins affected by anti‐mIgM stimulation during B‐cell maturation were identified using 2‐DE‐based proteomics. We investigated the proteome profiles of stimulated and nonstimulated Ramos B‐cells at eight time points during 5 d and compared the obtained proteomic data to the corresponding data from DNA‐microarray studies. Anti‐mIgM stimulation of the cells resulted in significant differences (≥twofold) in the protein abundance close to 100 proteins and differences in post‐translational protein modifications. Forty‐eight up‐ or down‐regulated proteins were identified by mass spectrometric methods and database searches. The identities of a further nine proteins were revealed by comparing their positions to the known proteins in other lymphocyte 2‐DE databases. Several of the proteins are directly related to the functional and morphological characteristics of B‐cells, such as cytoskeleton rearrangement and intracellular signalling triggered by the crosslinking of B‐cell receptors. In addition to proteins known to be involved in human B‐cell maturation, we identified several proteins that were not previously linked to lymphocyte differentiation. The results provide deeper insights into the process of B‐cell maturation and may lead to novel therapeutic strategies for immunodeficiencies. An interactive 2‐DE reference map is available at http://bioinf.uta.fi/BcellProteome.
An integrated approach to mapping the proteome of the human bone marrow stromal cell
Authors: Seshi Beerelli 
Published: August 2006

AbstractBone marrow stromal cells, also known as mesenchymal stem or progenitor cells, are thought to play a critical role in hematopoiesis. Because hematopoiesis is dysregulated in leukemic individuals, expression profiling in leukemic stromal cells might yield valuable insights into mechanisms of normal and dysregulated hematopoiesis. Here, proteomics was used to identify expressed proteins in normal and leukemic bone marrow stromal cells. Isobaric tags for relative and absolute quantification (iTRAQ) technology and MS/MS were used to identify and quantify proteins in bone marrow stromal cells from two normal and two leukemic individuals. Approximately 900 distinct proteins were identified with >95% confidence, 73 of which were differentially expressed in leukemic stromal cells. cDNA microarray analysis on Affymetrix oligonucleotide gene chips showed that transcripts correlated with approximately 90% of the expressed proteins. A novel integrated approach for mining and visualization of iTRAQ data is presented. The results provide an initial assessment of the proteome in human bone marrow stromal cells, laying the groundwork for comprehensive analysis of the proteome in these cells, and ultimately, for improved understanding of normal and dysregulated hematopoiesis.
A differentially expressed proteomic analysis in placental tissues in relation to pungency during the pepper fruit development
Authors: Lee Je Min , Kim Seyoon , Lee Ji Young , Yoo Eun Young , Cho Myeong Cheoul , Cho Min Rae , Kim Byung‐Dong , Bahk Young Yil 
Published: August 2006

AbstractUsing proteomic analysis including 2‐DE, image analysis, and protein identification with LC‐MS/MS, an investigation aimed at a better understanding of the differentially expressed proteins and/or gene products was carried out with total cell extracts from placental tissues in nonpungent (Capsicum annuumcv. Saeng‐Ryeog #213) and pungent peppers (C. annuumcv. Saeng‐Ryeog #211). Mobilization of the most abundant proteins, which were on the gels of pH ranges of 4–7, 4.5–5.5, 5.5–6.7, and 6–9, and showed very similar profiles in the two tissues, revealing approximately 2600 protein spots consisting of 1200 on pH 4–7, 600 on 4.5–5.5, 550 on 5.5–6.7, 250 on 6–9. Of these, 37 protein spots, which appeared in only pungent tissues but not in nonpungent tissues or markedly increased in their staining intensities on the gels from pungent tissue, were selected, excised, in‐gel trypsin digested, and analyzed by LC‐ESI‐MS/MS. Peptide MS/MS data were searched against publicly available protein and EST databases, and 22 proteins were identified. Based on this result, we tested and compared the differential expression during fruit development on the 2‐DE gels with total cell extracts from placental tissues of pungent and nonpungent peppers at an interval of 10 days from 10 to 40 days after flowering. In addition, this differential protein expression was further confirmed for some subsets of candidates by Northern‐blot analysis with RNA samples from placental tissues harvested from each pepper fruit at the same sampling intervals. In this study, the physiological implications, revealed from the experimental data in the levels of proteome and transcripts, are discussed in the context of a complex biosynthesis network of capsaicinoids in pepper cells responsive to pungency.