bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relaxometry model of strong dipolar perturbers for balanced‐SSFP: Application to quantification of SPIO loaded cells
Authors: Lebel R. Marc , Menon Ravi S. , Bowen Chris V. 
Published: January 2006

AbstractMagnetic resonance microscopy using magnetically labeled cells is an emerging discipline offering the potential for non‐destructive studies targeting numerous cellular events in medical research. The present work develops a technique to quantify superparamagnetic iron‐oxide (SPIO) loaded cells using fully balanced steady state free precession (b‐SSFP) imaging. An analytic model based on phase cancellation was derived for a single particle and extended to predict mono‐exponential decay versus echo time in the presence of multiple randomly distributed particles. Numerical models verified phase incoherence as the dominant contrast mechanism and evaluated the model using a full range of tissue decay rates, repetition times, and flip angles. Numerical simulations indicated a relaxation rate enhancement (ΔR2b=0.412γ · LMD) proportional to LMD, the local magnetic dose (the additional sample magnetization due to the SPIO particles), a quantity related to the concentration of contrast agent. A phantom model of SPIO loaded cells showed excellent agreement with simulations, demonstrated comparable sensitivity to gradient echo ΔR*2 enhancements, and 14 times the sensitivity of spin echo ΔR2 measurements. We believe this model can be used to facilitate the generation of quantitative maps of targeted cell populations. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Numerical equilibration of signal intensity and spatial resolution in time‐resolved continuously moving table imaging
Authors: Madhuranthakam Ananth J. , Hu Houchun H. , Kruger David G. , Riederer Stephen J. 
Published: January 2006

AbstractTime‐resolved continuously moving table imaging techniques have been previously developed to observe a dynamically changing phenomenon over an extended field‐of‐view. The acquisition involves differential k‐space sampling and view sharing. Since the table is continuously moving during data acquisition, the k‐space for any longitudinal position is sampled only sparsely for the first reconstruction timeframe and is progressively more fully sampled for subsequent frames. Consequently, the signal intensity increases and the lateral spatial resolution improves from frame to frame even for static materials, which can mask true dynamically changing phenomena. This work provides a description of this effect and a means for signal correction in the early reconstruction frames, thus permitting any residual variation in signal intensity to be primarily attributed to true dynamic processes. The method is tested experimentally on a static phantom and in a peripheral vascular study designed to observe the leading edge of the contrast bolus. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Fast and reliable analysis of free‐edge stress fields in a thermally loaded composite strip by a layerwise laminate theory
Authors: Mittelstedt Christian , Becker Wilfried 
Published: January 2006

AbstractA layerwise theory for the analysis of free‐edge effects in thermally loaded symmetric laminates with arbitrary layups is developed. The laminate under investigation is decomposed into an arbitrary number of mathematical layers through the thickness. The theory approach employs displacement terms according to Classical Laminate Plate Theory which are upgraded by layerwise displacement functions. The additional layerwise displacement functions consist of unknown inplane functions and linear thickness terms. The principle of minimum potential energy yields the governing Euler–Lagrange equations which allow for a closed‐form analytical solution for the inplane functions, thus characterizing this method as a semi‐analytical one. The underlying boundary conditions of traction free edges are fulfilled in an integral sense. The present results are in excellent agreement with accompanying finite element computations. Copyright © 2006 John Wiley & Sons, Ltd.
Fourier methods for quasi‐periodic oscillations
Authors: Schilder Frank , Vogt Werner , Schreiber Stephan , Osinga Hinke M. 
Published: January 2006

AbstractQuasi‐periodic oscillations and invariant tori play an important role in the study of forced or coupled oscillators. This paper presents two new numerical methods for the investigation of quasi‐periodic oscillations. Both algorithms can be regarded as generalizations of the averaging and the harmonic (spectral) balance methods. The algorithms are easy to implement and require only minimal a priori knowledge of the system. Most importantly, the methods do not depend on an a priori co‐ordinate transformation. The methods are applied to a number of illustrative examples from non‐linear electrical engineering and the results show that the methods are efficient and reliable. In addition, these examples show that the presented algorithms can also continue through regions of sub‐harmonic (phase‐locked) resonance even though they are designed only for the quasi‐periodic case. Copyright © 2006 John Wiley & Sons, Ltd.
A quadrature formula for integrals with nearby singularities
Authors: Tsamasphyros G. , Theotokoglou E. E. 
Published: January 2006

AbstractThe purpose of this paper is to propose a new quadrature formula for integrals with nearby singularities. In the boundary element method, the integrands of nearby singular boundary integrals vary drastically with the distance between the field and the source point. Especially, field variables and their derivatives at a field point near a boundary cannot be computed accurately. In the present paper a quadrature formula for 𝓁‐isolated singularities near the integration interval, based on Lagrange interpolatory polynomials, is obtained. The error estimation of the proposed formula is also given. Quadrature formulas for regular and singular integrals with conjugate poles are derived. Numerical examples are given and the proposed quadrature rules present the expected polynomial accuracy. Copyright © 2006 John Wiley & Sons, Ltd.
A stabilized nodally integrated tetrahedral
Authors: Puso M. A. , Solberg J. 
Published: January 2006

AbstractA stabilized, nodally integrated linear tetrahedral is formulated and analysed. It is well known that linear tetrahedral elements perform poorly in problems with plasticity, nearly incompressible materials, and acute bending. For a variety of reasons, low‐order tetrahedral elements are preferable to quadratic tetrahedral elements; particularly for nonlinear problems. But the severe locking problems of tetrahedrals have forced analysts to employ hexahedral formulations for most nonlinear problems. On the other hand, automatic mesh generation is often not feasible for building many 3D hexahedral meshes. A stabilized, nodally integrated linear tetrahedral is developed and shown to perform very well in problems with plasticity, nearly incompressible materials and acute bending. The formulation is analytically and numerically shown to be stable and optimally convergent for the compressible case provided sufficient smoothness of the exact solution u ∈ C2 ∩ (H1)3. Future work may extend the formulation to the incompressible regime and relax the regularity requirements; nonetheless, the results demonstrate that the method is not susceptible to locking and performs quite well in several standard linear and nonlinear benchmarks. Published in 2006 by John Wiley & Sons, Ltd.
Recent developments in the use of two‐photon polymerization in precise 2D and 3D microfabrications
Authors: Lee Kwang‐Sup , Yang Dong‐Yol , Park Sang Hu , Kim Ran Hee 
Published: January 2006

AbstractThe use of two‐photon polymerization (TPP) initiated by a photosensitizer's non‐linear two‐photon absorption in two‐ and three‐dimensional (2D and 3D) microfabrications for various photonic applications has been intensively studied. Since TPP emerged as a new technology over a decade ago, a large variety of micro‐objects including 3D micro‐optical components, micromechanical devices, and 3D photonic crystals have been fabricated using TPP with a high spatial resolution of approximately submicron scale to 100 nm. Recent efforts have been made to improve the fabrication efficiency and precision of micro‐objects obtained with TPP; in particular, many studies have been carried out with the aim of developing efficient two‐photon absorbing chromophores. In this article, efforts to develop highly efficient two‐photon absorbing materials and also describe recent attempts to enhance the resolution and improve the fabrication efficiency of nanofabrications based on two‐photon polymerization are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Fetomaternal hemorrhage in relation to chorionic villus sampling revisited
Authors: Pelikan Denise M. , Kanhai Humphrey H. , De Groot‐Swings Godelieve M. , Mesker Wilma E. , Tanke Hans J. , Scherjon Sicco A. 
Published: January 2006

AbstractObjectiveTo investigate whether chorionic villus sampling (CVS) results in a proportional increase of alpha‐fetoprotein (AFP) and fetal red cells in maternal blood.MethodsBlood samples were collected before and after CVS. The AFP concentration was measured and supervised automated microscopy of Kleihauer–Betke slides was applied to quantify fetal red cells.ResultsAFP analysis was performed in 53 paired samples and automated microscopic scanning in 59 paired samples. Median AFP concentrations before and after CVS were 12.0 µg/L (range 6.4–36.4) and 18.7 µg/L (range 8.2–668.9), respectively, indicating a significant increase (p < 0.0001). Median numbers of fetal red cells detected before and after CVS were 0 (range 0–36) and 0 (range 0–31), respectively. No significant increase of fetal cells was observed (p = 0.72). The delta (Δ) fetal red cells and the Δ AFP correlated poorly (ρ = −0.22, p = 0.11). The amount of villi correlated moderately with the Δ AFP (ρ = 0.32, p = 0.02) and did not correlate with the Δ fetal red cells (ρ = −0.11, p = 0.43).ConclusionsAlthough the AFP concentration after CVS increased, no increase of fetal red cells was detected. These findings suggest that CVS results in a leakage of proteins due to placental tissue damage, rather than increased trafficking of fetal cells. Copyright © 2006 John Wiley & Sons, Ltd.
Prenatal findings in four consecutive pregnancies with fetal Pierson syndrome, a newly defined congenital nephrosis syndrome
Authors: Mark Karlheinz , Reis André , Zenker Martin 
Published: January 2006

AbstractObjectiveTo describe the prenatal findings in Pierson syndrome, a newly defined autosomal recessive entity, comprising congenital nephrotic syndrome (CNS) with diffuse mesangial sclerosis and distinct eye abnormalities due to LAMB2 mutations.MethodsSerial prenatal ultrasound examinations were performed in four consecutive pregnancies affected by Pierson syndrome in the same family. LAMB2 mutations were demonstrated in retrospect by direct sequencing of the gene in the newborn index patient and three abortuses.ResultsFetal ultrasound consistently revealed marked renal hyperechogenicity associated with variable degree of pyelectasis. These features were detectable by 15 weeks of gestation in all fetuses. Hydrops fetalis due to severe hypalbuminemia demonstrated by chordocentesis occurred in one fetus. Placentas were significantly enlarged. Development of oligohydramnios indicated prenatal decline of renal excretory function. Anencephaly was detected in another fetus with molecularly proven Pierson syndrome at 12 weeks of gestation.ConclusionWe conclude that Pierson syndrome has to be considered in the differential diagnosis of nephrotic disorders with prenatal onset. Ultrasound criteria for differentiation from the most common type of CNS–congenital nephrosis of the Finnish type (CNF)–are discussed. Because of its prognostic relevance, we advocate molecular genetic testing of LAMB2 in any case of prenatally detected nephrotic syndrome with negative results of NPHS1 mutational screening, especially in the presence of the typical sonomorphologic findings of the kidneys and the development of oligohydramnios. Copyright © 2006 John Wiley & Sons, Ltd.
Intermittent administration of morphine alters protein expression in rat nucleus accumbens
Authors: Li Ka Wan , Jimenez Connie R. , van der Schors Roel C. , Hornshaw Martin P. , Schoffelmeer Anton N. M. , Smit August B. 
Published: January 2006

AbstractRepeated exposure to drugs of abuse causes time‐dependent neuroadaptive changes in the mesocorticolimbic system of the brain that are considered to underlie the expression of major behavioral characteristics of drug addiction. We used a 2‐D gel‐based proteomics approach to examine morphine‐induced temporal changes in protein expression and/or PTM in the nucleus accumbens (NAc) of morphine‐sensitized rats. Rats were pretreated with saline [1 mL/kg subcutaneously (s.c.)] or morphine (10 mg/kg, s.c.) once daily for 14 days and the animals were decapitated 1 day later. The NAc was extracted and proteins resolved by 2‐DE. Several protein functional groups were found to be regulated in the morphine‐treated group, representing cytoskeletal proteins, proteins involved in neurotransmission, enzymes involved in energy metabolism and protein degradation, and a protein that regulates translation.
Down‐regulation of the strawberry Bet v 1‐homologous allergen in concert with the flavonoid biosynthesis pathway in colorless strawberry mutant
Authors: Hjernø Karin , Alm Rikard , Canbäck Björn , Matthiesen Rune , Trajkovski Karin , Björk Lars , Roepstorff Peter , Emanuelsson Cecilia 
Published: January 2006

AbstractProteomic screening of strawberry (Fragaria ananassa) yielded a 58% success rate in protein identification in spite of the fact that no genomic sequence is available for this species. This was achieved by a combination of MALDI‐MS/MS de novo sequencing of double‐derivatized peptides and indel‐tolerant searching against local protein databases built on both EST and full‐length nucleotide sequences. The amino acid sequence of a strawberry allergen, homologous to the well‐known major birch pollen allergen Bet v 1, was partially determined. This strawberry allergen, named Fra a 1 according to the nomenclature for allergen proteins, showed sequence identity of 54 and 77%, respectively, with corresponding allergens from birch and apple. Differential expression, as evaluated by 2‐D DIGE, occurred in 10% of protein spots when red strawberries were compared to a colorless (white) strawberry mutant. White strawberries, known to be tolerated by individuals affected by allergy, were found to be virtually free from the strawberry allergen. Also several enzymes in the pathway for biosynthesis of flavonoids, to which the red color pelargonidin belongs, were down‐regulated. This approach to assess differential protein expression without access to genomic sequence information can also be applied to other crop plants and phenotypic traits.
Prediction of experimentally unknownredistances of organic molecules from Dunning basis set extrapolations forab initiopost‐HF calculations
Authors: Neugebauer Alexander , Häfelinger Günter 
Published: January 2006

AbstractAn approach to estimate equilibriumrebond lengths of organic molecules which contain standard bonding situations for CC, CH, CO and CN distances from only one equation is presented. For this, optimizations of molecular geometries using correlated post‐Hartree–Fock and density functional methods have been performed. A selection scheme was developed to determine the most reliable methodology for prediction of equilibriumredistances of covalent bonds from a set of investigated theoretical methods. Consequently, distances computed in the CCSD(T) procedure via exponential extrapolation from a consecutive set of Dunning cc‐pVXZ basis sets by use of Eqn (2) are accurate up to ± 0.0005 Å in comparison to experimentally availableredistances. Applications for predictions of the experimentally unknownredistances of methanol, methylamine and methylenimine are presented.Additionally the estimation ofredistances of larger, chemically more interesting molecules is possible by lower order calculations (e.g. DFT B3LYP/cc‐pVDZ) via linear correlation statistics using the results from ourrereference model system via Eqn (3). Copyright © 2006 John Wiley & Sons, Ltd.
Cocuring behaviors of benzoxazine and maleimide derivatives and the thermal properties of the cured products
Authors: Liu Ying‐Ling , Yu Juin‐Meng 
Published: January 2006

AbstractThe cocuring behaviors of 3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine (P‐ABz) and various N‐phenylmaleimide compounds were studied with DSC, FTIR, and TGA‐GC/MS. The presence of benzoxazine compound promoted the polymerization of maleimide groups. In contrast, 4‐hydroxyphenylmaleimide (MI‐OH) and 4‐maleimidobenzoic acid (MI‐COOH), which possess acidic moieties, showed an acid‐catalytic effect on the polymerization of benzoxazine groups. The cocuring composition of P‐ABz/MI‐COOH showed low polymerization temperatures, high glass transition temperature above 220 °C, and comparable thermal stability to conventional polybenzoxazines. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1890–1899, 2006
Atom transfer graft copolymerization of 2‐ethyl hexylacrylate from labile chlorines of poly(vinyl chloride) in an aqueous suspension
Authors: Bicak Niyazi , Karagoz Bunyamin , Emre Dilek 
Published: January 2006

AbstractCopper‐mediated atom transfer radical polymerization (ATRP) is presented as a versatile tool for the graft copolymerization of 2‐ethyl hexylacrylate with poly(vinyl chloride) (PVC) in an aqueous suspension. The appreciable solubility of PVC in 2‐ethyl hexylacrylate (30%) at temperatures around 130 °C makes grafting of the monomer possible from labile chlorines of PVC in aqueous suspensions without the use of additional solvent. The first‐order kinetics (rate constant k = 4.2 × 10−6 s−1) of the mass percentage increase reveals a typical ATRP fashion of the graft copolymerization at low conversions. The use of a completely organosoluble copper(I) complex of hexylated triethylene tetramine, in combination with α‐methylcellulose as a stabilizer, makes the graft copolymerization possible in a dispersed organic phase. Nearly spherical, green particles can be obtained with moderate stirring rates (1000 rpm) in high graft yields. Although the kinetics of the reaction deviates from the first order at high conversions, reasonable graft yields (146%) can be attained within a reaction period of 24 h. In this study, the reaction conditions of the grafting have been studied, and graft products have been confirmed by common techniques such as 1H NMR, gel permeation chromatography, and differential scanning calorimetry. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1900–1907, 2006
Phase separation, porous structure, and cure kinetics in aliphatic epoxy resin containing hyperbranched polyester
Authors: Guo Qipeng , Habrard Alexia , Park Yoosup , Halley Peter J. , Simon George P. 
Published: January 2006

AbstractThermosetting blends of an aliphatic epoxy resin and a hydroxyl‐functionalized hyperbranched polymer (HBP), aliphatic hyperbranched polyester Boltorn H40, were prepared using 4,4′‐diaminodiphenylmethane (DDM) as the curing agent. The phase behavior and morphology of the DDM‐cured epoxy/HBP blends with HBP content up to 40 wt % were investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). The cured epoxy/HBP blends are immiscible and exhibit two separate glass transitions, as revealed by DMA. The SEM observation showed that there exist two phases in the cured blends, which is an epoxy‐rich phase and an HBP‐rich phase, which is responsible for the two separate glass transitions. The phase morphology was observed to be dependent on the blend composition. For the blends with HBP content up to 10 wt %, discrete HBP domains are dispersed in the continuous cured epoxy matrix, whereas the cured blend with 40 wt % HBP exhibits a combined morphology of connected globules and bicontinuous phase structure. Porous epoxy thermosets with continuous open structures on the order of 100–300 nm were formed after the HBP‐rich phase was extracted with solvent from the cured blend with 40 wt % HBP. The DSC study showed that the curing rate is not obviously affected in the epoxy/HBP blends with HBP content up to 40 wt %. The activation energy values obtained are not remarkably changed in the blends; the addition of HBP to epoxy resin thus does not change the mechanism of cure reaction of epoxy resin with DDM. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 889–899, 2006
Pressure‐induced metallization and structural evolution of Cu3N
Authors: Zhao J. G. , Yang L. X. , Yu Y. , You S. J. , Liu J. , Jin C. Q. 
Published: January 2006

AbstractIn situ resistance evolution with pressure of anti‐perovskite nitride Cu3N was measured using the diamond anvil cell (DAC) technique up to 20.0 GPa at room temperature. A sharp drop of resistance from 105 Ω at ambient pressure to several Ω was observed in the range 3.0–10.0 GPa. This is an indication of the pressure‐induced metallization in the Cu3N semiconductor. Meanwhile we also performed the high‐pressure energy dispersive X‐ray diffraction experiments on Cu3N at the pressures up to 39.2 GPa. It was found that a crystal structure phase transition begins to take place at ∼5.0 GPa on Cu3N, which is generally consistent with the electronic conductance results. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient coupling into confined optical modes of ZnSe‐based pillar microcavities
Authors: Lohmeyer H. , Sebald K. , Gutowski J. , Kruse C. , Hommel D. , Wiersig J. , Baer N. , Jahnke F. 
Published: January 2006

AbstractMonolithic II–VI pillar microcavities made of ZnCdSSe/ZnSSe λ cavities and Bragg mirrors composed of ZnSSe and MgS/ZnCdSe supperlattices have been fabricated by molecular‐beam epitaxy and focused‐ion‐beam etching. Discrete optical modes of the pillar microcavities are studied in photoluminescence measurements. The measured data show full agreement with calculations based on an extended transfer‐matrix method. A strong enhancement in the detected photoluminescence signal is obtained for single emitters in resonance with modes of the cavity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magneto‐optical properties in hybrid nanostructures of II–VI diluted magnetic semiconductors with perpendicular ferromagnetic films
Authors: Sakuma M. , Hyomi K. , Souma I. , Murayama A. , Oka Y. 
Published: January 2006

AbstractHybrid nanostructures of a diluted magnetic semiconductor quantum well (DMS‐QW) of Zn1–x –y Cdx Mny Se have been fabricated with a ferromagnetic Co/Pt‐multilayered film, by electron beam lithography. The disk structure of the DMS‐QW with the diameter of 100 nm was embedded in the magnetic thin film with the thickness of 50 nm. Giant Zeeman effects of excitons in the DMS‐QW in the hybrid structure are studied by micro‐photoluminescence (PL) spectroscopy. The Co/Pt film shows perpendicular magnetization without external field, and therefore it can generate magnetic fields nearly perpendicular to the DMS‐QW plane in the hybrid structure. As the result, the circularly polarized excitonic PL arises in zero external field, indicating that the perpendicular magnetic field applied from the Co/Pt film aligns the exciton spins in the DMS‐disk in the present hybrid structure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)