bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of the Upper Pleistocene terraces of Lake Van (Turkey)
Authors: Kuzucuoğlu Catherine , Christol Aurélien , Mouralis Damase , Doğu Ali‐Fuat , Akköprü Ebru , Fort Monique , Brunstein Daniel , Zorer Halil , Fontugne Michel , Karabiyikoğlu Mustafa , Scaillet Stéphane , Reyss Jean‐Louis , Guillou Hervé
Published: September 2010

Sedimentological and geomorphological studies of terraces around Lake Van (1647 m) provided a preliminary framework for lake‐level variations. The elevations of terraces and past lake level were measured with a differential global positioning system. A chronology is developed using 234U/230Th dating of travertines, 39Ar/40Ar dating of pyroclastites and 14C dating of organic matter. Facies and stratigraphic correlations identify four transgressions (C1′, C1″, C2′ and C2″), each followed by a regression which ended with low lake levels that caused river incision and terrace formation. Evidence of the oldest transgression (C1′) is found in the uppermost reaches of valleys up to 1755 m, an altitude higher than the present lake threshold (1736 m). This C1′ transgression may be related to pyroclastic flows which dammed an outlet located in the western part of the lake basin and which is dated to before 105 ka. After 100 ka, a second transgression (C1″) reached 1730/1735 m, possibly related to a younger ignimbrite flow, in association with high water inflow (warm and/or wetter conditions). The two younger transgressions reached 1700–1705 m. The first one (C2′) is dated to 26–24.5 cal. ka BP and the second one (C2″) to 21–20 cal. ka BP. Available data suggest that the long‐term lake‐level changes responded mainly to climate oscillations. Additional events such as river captures caused by volcanic falls filling valleys, tectonism, erosion and karstic diversion may have impacted these long‐term lake‐level changes. Copyright © 2010 John Wiley & Sons, Ltd.
A Raman spectroscopic study of the igneous rocks on Marion Island: a possible terrestrial analogue for the geology on Mars
Authors: Prinsloo Linda C. , Colomban Philippe , Brink Johan D. , Meiklejohn Ian
Published: September 2010

The geology of Marion Island is typical of the oceanic volcanoes forming the Hawaiian archipelago, which is generally seen as an analogue for the geology on Mars. Because of the cold climate, the relatively young igneous rocks on Marion Island exhibit no visible alteration from the original rocks, and we used Raman spectroscopy to study examples of the igneous rocks on the island as potential model substances for the parent material on Mars. Three types of volcanic material were studied: namely, a grey lava (270 000–70 000 BP) as well as black lava and red scoriae cones, both formed at a later date (12 000 BP to present). A few Raman spectra of volcanic ash from the island are included for comparison purposes. The basic elemental content of the three different lavas are the same by X‐ray fluorescence (XRF), but there is a variation in the relative amounts of crystalline and amorphous phases present in X‐ray diffraction (XRD) data and Raman measurements, which can be related to cooling rate and oxidising conditions during the formation process. Fosterite, sanidine, labrodorite, anorthite and diopside were identified in the grey lava. In the black lava, broad bands in the spectra indicated the presence of many amorphous phases, but fosterite, anorthite, diopside, magnetite and ulvöspinel could be identified through their Raman spectra. In the red scoriae, fosterite, anorthite, diopside, hematite and pseudobrookite were identified, the last two minerals acting as colouring agent. Haematite was also identified as a thin layer covering feldspar glass. The spectra of the volcanic ash vary much and represent a variety of amorphous/glassy phases. This study emphasises the strength of Raman spectroscopy to identify a whole range of disordered phases. Copyright © 2010 John Wiley & Sons, Ltd.
New evidences of in situ laser irradiation effects on γ‐Fe2O3 nanoparticles: a Raman spectroscopic study
Authors: El Mendili Y. , Bardeau J.‐F. , Randrianantoandro N. , Gourbil A. , Greneche J.‐M. , Mercier A.‐M. , Grasset F.
Published: September 2010

The nature of the physical mechanisms responsible for the structural modification of the γ‐Fe2O3 nanoparticles under laser irradiation has been investigated by Raman spectroscopy. In situ micro‐Raman measurements were carried out on as‐prepared γ‐Fe2O3 nanoparticles about 4 nm in size as a function of laser power and on annealed γ‐Fe2O3 particles. A baseline profile analysis clearly evidenced that the phase transition from maghemite into hematite is caused by local heating due to laser irradiation with an increase of grain size of nanoparticles. This increasing was clearly determined by X‐ray diffraction from 4 nm in nanoparticles up to more than 177 nm beyond 900 °C in a polycrystalline state. Copyright © 2010 John Wiley & Sons, Ltd.
Evaluation of crystalline perfection degree of multi‐walled carbon nanotubes: correlations between thermal kinetic analysis and micro‐Raman spectroscopy
Authors: Santangelo S. , Messina G. , Faggio G. , Lanza M. , Milone C.
Published: September 2010

Commercially available and laboratory‐prepared multi‐walled carbon nanotubes (MWCNTs) are systematically investigated by the use of micro‐Raman spectroscopy (MRS), thermogravimetric analysis (TGA) and complementary techniques (scanning electron microscopy (SEM) and transmission electron microscopy (TEM)) with the aim of establishing a standardised post‐growth diagnostic protocol for the assessment of their overall crystalline quality. By studying a set of ‘reference’ samples, clear correlations are evidenced between the Raman graphitisation indexes (D/G, G′/G and G′/D intensity ratios) commonly adopted to describe the crystalline arrangement of nanotubes, and their reactivity towards oxygen, as measured by the apparent activation energy needed for their oxidation, inferred from the kinetic analysis in quasi‐isothermal conditions. The higher the crystalline perfection degree, the higher the energy needed for oxidising them. The efficacy of the found correlations in indirectly assessing the reactivity of nanotubes prepared under different conditions is successfully demonstrated by the use of a second set of samples. The physical meaning and range of validity of the shown correlations are further discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Identification of chemical modification in single human keratinocyte cells exposed to low doses of chlorpyriphos by Raman micro‐spectroscopy
Authors: Perna G. , Lasalvia M. , D'Antonio P. , L'Abbate N. , Capozzi V.
Published: September 2010

Raman micro‐spectroscopy can be used to investigate biological single cells exposed to different chemicals. Since chronic exposure at low doses of pesticides can promote several diseases, the investigation of cellular changes induced by exposure to non‐cytotoxic doses of pesticides is of increasing interest. The efficiency of Raman micro‐spectroscopy to detect chemical modification in normal human keratinocytes induced by exposure to non‐cytotoxic doses of chlorpyriphos, an organophosphate pesticide present in many plant‐protection products, was investigated. Such modification affects mainly proteineous components (both single amino acids and amide linkages between amino acids) of the nucleus, cellular membranes and cytoplasm as well as the nucleic acid component of the nucleus. Chemical modifications are already detectable after 24 h exposure of keratinocytes at a chlorpyriphos concentration of 10−6 M, which is three orders of magnitude lower than the cytotoxic concentration (10−3 M). Heavy damage to the lipid component occurs after exposure to the nearly cytotoxic concentration (10−4 M). Atomic force microscopy images of keratinocyte cells exposed for 24 h to various chlorpyriphos concentrations show a progressive deterioration of the morphology of cellular membrane as the chlorpyriphos concentration increases. The results of this work may have wide applications in the monitoring of molecular changes in single human cells exposed to toxic agents. Copyright © 2010 John Wiley & Sons, Ltd.
Reversed‐phase HPLC of peptides: Assessing column and solvent selectivity on standard, polar‐embedded and polar endcapped columns
Authors: Mant Colin T. , Cepeniene Dziuleta , Hodges Robert S.
Published: September 2010

We desired to evaluate the chromatographic selectivity for peptides of silica‐based RP high‐performance liquid chromatography stationary phases with various modifications (polar embedding and polar endcapping on C18 columns; ether‐linked phenyl column with polar endcapping) compared with n‐alkyl (C18, C8) and aromatic phenylhexyl columns. Thus, we have designed and synthesized two series of synthetic peptide standards with the sequence Gly–Gly–Leu–Gly–Gly–Ala–Leu–Gly–X–Leu–Lys–Lys–amide, where the N‐terminal either contains a free α‐amino group (AmC series) or is Nα‐acetylated (AcC series) and where position X is substituted by Gly, Ala, Val, Ile, Phe or Tyr. These represent series of peptides with single substitutions of n‐alkyl (Gly<Ala<Val<Ile in order of increasing hydrophobicity), alkyl versus aromatic side‐chains (Phe, Tyr) and a side‐chain also with polar character (Tyr). Peptide mixtures were run on all columns at pH 2 (linear gradients of ACN or methanol in aqueous mobile phases). Our initial results clearly demonstrate the useful complementarity of different RP high‐performance liquid chromatography packing materials, with peptide mixtures showing profound selectivity differences between n‐alkyl versus polar‐embedded and polar endcapped C18 stationary phases. In addition, changing the polarity of the RP matrix in combination with changing the polarity of the mobile phase (ACN versus methanol) is shown to be synergistic to maximize selectivity of peptide separations.
Laser assisted septal cartilage reshaping (LASCR): A prospective study in 12 patients
Authors: Leclère Franck M. , Petropoulos Ioannis , Buys Bruno , Mordon Serge
Published: September 2010

Background and Objectives

Occurring in one‐third of the population, nasal obstruction is the most common complaint in an average rhinologic practice. The etiology is usually a deviation of the nasal septum, although other conditions, such as turbinate hypertrophy, can also cause nasal obstruction. Our team has already demonstrated that laser assisted cartilage reshaping can be used effectively for the correction of ear protrusion. This study aims to evaluate laser assisted septal cartilage reshaping (LASCR) to treat septal deviation.

Study Design

Between March 2009 and September 2009, 12 patients (8 males, 4 females—mean age: 23 years) underwent LASCR for treatment of septal deviation. The mean NOSE score was 11.6. Preoperative examination included rhinomanometry and nasal endoscopy to exclude inferior turbinate or adenoid hypertrophy. Both sides of the septum were irradiated using a 1,540 nm laser connected to a 4 mm spot handpiece with integrated cooling (fluence: 50 J/cm2). Contact cooling made the treatment tolerable, but topical anesthesia was still required. Immediately after the procedure, an internal splint was inserted into the nostril and kept for 7 days. The NOSE score was calculated at 1 week, 1 month, and 3 months post‐procedure and a rhinomanometry was carried out at 3 months.

Results

The entire procedure took an average of 20 minutes. For all procedures, there were no lesions of the septal mucosa. Three months post‐op, mean NOSE score improved from 11.6 to 5.3. Rhinomanometry assesses an increase in airflow (+19%) and improvement to air inflow resistance (−16%), confirming a subjective improvement. In seven adults, the expected septal reshaping was achieved. In five adults, incomplete septum reshaping was observed. In three patients it was correlated to anatomical variations: a thick septum in two cases and a long septum in one case. In the remaining two patients, it was due to insufficient fluence. In these cases, insufficient local anesthesia did not allow us to finish the procedure and the patients received a fluence of 30 J/cm2 only. Those patients were re‐treated at 3 months at 50 J/cm2 fluence and all achieved suitable reshaping.

Conclusion

LASCR is a safe and less morbid approach to surgical septoplasty. Since significant variability in the cartilaginous elements of the nose is the rule rather than the exception, some improvements in the technique are still required. Lasers Surg. Med. 42:693–698, 2010 © 2010 Wiley‐Liss, Inc.
The immunosuppressive pipeline: Meeting unmet needs in liver transplantation
Authors: Selzner Nazia , Grant David R. , Shalev Itay , Levy Gary A.
Published: September 2010

Liver transplantation is now recognized as the treatment of choice for end-stage liver failure. Its success can be attributed largely to the generation of selective immunosuppressive agents, which have resulted in a dramatic reduction in the incidence of acute rejection and improvements in the short- and long-term outcomes of patients. However, the unresolved limitation of current immunosuppressive agents is long-term toxicity, which results in increases in the incidence and severity of cardiovascular, neurological, and renal diseases. Our recent understanding of the pathways of cell activation has resulted in the development of a new generation of immunosuppressive agents that may address the challenges facing transplantation today and allow the minimization or substitution of existing agents. Furthermore, advances in our understanding of the mechanisms of tolerance and the identification of biomarker signatures hold the promise that in some patients transplantation may be able to be performed without the need for long-term immunosuppression (tolerance). Liver Transpl 16:1359–1372, 2010. © 2010 AASLD.
Blood Compatibility and Permeability of Heparin‐Modified Polysulfone as Potential Membrane for Simultaneous Hemodialysis and LDL Removal
Authors: Huang Xiao‐Jun , Guduru Deepak , Xu Zhi‐Kang , Vienken Jörg , Groth Thomas
Published: September 2010

Heparin was covalently immobilized on PSf membranes to obtain a dialysis membrane with high affinity for LDL. WCA and streaming potential measurements were performed to investigate wettability and surface charge of the membranes. The morphology of the membranes was investigated by SEM. An ELISA was used to measure the adsorption and desorption of LDL on plain and modified PSf. Blood compatibility was studied by measurement of thrombin time, partial thromboplastin time, kallikrein activity and platelet adhesion. It was found that the blood compatibility of the membrane was improved by covalent immobilization of heparin at its surface. However, PSf‐Hep membrane showed higher flux recovery after BSA solution filtration, which revealed antifouling property of PSf‐Hep membranes.

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A Novel Crystallization Scheme in Poly[styrene‐block‐(ferrocenyl dimethylsilane)] Diblock Copolymers
Authors: Xu Jianjun , Bellas Vasilios , Jungnickel Bernd , Stühn Bernd , Rehahn Matthias
Published: September 2010

Isothermal crystallization of the poly(ferrocenyl dimethylsilane) (PFDMS) segments in a poly[styrene‐block‐(ferrocenyl dimethylsilane)] (PS‐b‐PFDMS) diblock copolymer of lamellar micro‐morphology has been investigated. The PFDMS is shown to crystallize in a confined and grain‐by‐grain fashion. Here a ‘grain’ is defined as an ensemble of stacked lamellae wherein the PFDMS crystallization spreads quickly but stops at its surroundings. Such crystallization propagates not only along the PFDMS lamellae but across the amorphous PS layers as well. We suggest that conformational changes in the PS as induced by the PFDMS crystallization (‘squeezing transfer’) are responsible for the latter pathway of the crystallization's spread.

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Catechol‐O‐methyltransferase val158met and cognitive function in Parkinson's disease
Authors: Hoogland Jeroen , de Bie Rob M.A. , Williams‐Gray Caroline H. , Muslimović Dino , Schmand Ben , Post Bart
Published: September 2010

Cognitive dysfunction is one of the most incapacitating non‐motor symptoms of Parkinson's disease (PD). Some cognitive deficits are thought to be related to abnormal dopamine homeostasis. The latter is influenced by catechol‐O‐methyltransferase (COMT), an enzyme that degrades dopamine. Previous research suggests a relationship between the COMT val158met functional polymorphism (SNP) and measures of executive function. We evaluated this hypothesis in a cohort of PD patients with an extensive neuropsychological test battery. Cognitive assessment and COMT genotyping were performed in 153 early PD patients from outpatient clinics general hospitals in the Netherlands. Our results do not support a direct effect of COMT val158met genotype on performance on neuropsychological measures of attention and executive function, but they suggest that genotype may interact with dopaminergic medication use to influence cognitive ability. © 2010 Movement Disorder Society
NMR spectral assignment of 2α‐ and 3β‐methylhopanes and evidence for boat conformation in D ring of 17α(H),21α(H)‐hopanes
Authors: Kildahl‐Andersen Geir , Nytoft Hans Peter , Johansen Jon Eigill
Published: September 2010

The full 1H and 13C NMR chemical shift assignment of 2α‐methyl‐17α(H),21β(H)‐hopane is presented. This compound is formed in mature sediments from biogenic sources of 2β‐methyl‐17β(H),21β(H)‐hopanoids, which include several cyanobacteria. In addition, full 1H and 13C NMR chemical shift data of all four 17,21 isomers of 3β‐methylhopane have been assigned. The thermodynamically most stable 3β‐configuration corresponds to that found in bacterial sources. The data presented here suggest minor corrections to the 13C chemical assignments reported earlier for 17α(H)‐hopanes. Moreover, spectral evidence indicates an unexpected ring‐D boat conformation of 17α(H),21α(H)‐hopanes, which may serve to explain the steric strain reported for this isomer. Copyright © 2010 John Wiley & Sons, Ltd.
Feasibility of Tubular Microreactors for Emulsion Polymerization
Authors: Yadav Arvind Kumar , de la Cal José Carlos , Barandiaran María Jesús
Published: September 2010

The viability of a tubular microreactor for the production of polymer dispersions by emulsion polymerization was investigated. The reactor setup and operational conditions necessary to reach a very stable reactor operation were determined. It was found that stability of pre‐emulsion plays a very important role in achieving steady‐state performance. Further, the flow pattern of the microreactor was characterized, observing that the dispersion model can be used because of the effect of the radial molecular diffusion. Finally, a comparative study of the styrene emulsion polymerization in microreactor and batch laboratory reactor was performed. Similar kinetics and properties were achieved, indicating enough mixing in the microreactor.

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Transurethral prostate magnetic resonance elastography: Prospective imaging requirements
Authors: Arani Arvin , Plewes Donald , Chopra Rajiv
Published: September 2010

Tissue stiffness is known to undergo alterations when affected by prostate cancer and may serve as an indicator of the disease. Stiffness measurements can be made with magnetic resonance elastography performed using a transurethral actuator to generate shear waves in the prostate gland. The goal of this study was to help determine the imaging requirements of transurethral magnetic resonance elastography and to evaluate whether the spatial and stiffness resolution of this technique overlapped with the requirements for prostate cancer detection. Through the use of prostate‐mimicking gelatin phantoms, frequencies of at least 400 Hz were necessary to obtain accurate stiffness measurements of 10 mm diameter inclusions, but the detection of inclusions with diameters as small as 4.75 mm was possible at 200 Hz. The shear wave attenuation coefficient was measured in vivo in the canine prostate gland, and was used to predict the detectable penetration depth of shear waves in prostate tissue. These results suggested that frequencies below 200 Hz could propagate to the prostate boundary with a signal to noise ratio (SNR) of 60 and an actuator capable of producing 60 μm displacements. These requirements are achievable with current imaging and actuator technologies, and motivate further investigation of magnetic resonance elastography for the targeting of prostate cancer. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Flip‐angle measurement by magnetization inversion: Calibration of magnetization nutation angle in hyperpolarized 3He magnetic resonance imaging lung experiments
Authors: Rivoire J. , Terekhov M. , Meise F. M. , Gast K. , Salhi Z. , Schreiber L. M.
Published: September 2010

The aim of this work was to establish a new, fast, and robust method of flip‐angle calibration for magnetic resonance imaging of hyperpolarized 3He. The method called flip‐angle measurement with magnetization inversion is based on acquiring images from periodically inverted longitudinal magnetization created using the spatial modulation of magnetization technique. By measuring the width of the area where the magnetization was inverted by the spatial modulation of magnetization preparation in phase images, the flip angle can be generated using a simple equation. To validate and establish the limits of the proposed method, flip‐angle measurement with magnetization inversion acquisitions were simulated and applied to proton and hyperpolarized 3He phantoms. Then, the calibration procedure was applied during hyperpolarized 3He magnetic resonance imaging in a healthy volunteer. The advantage of the flip‐angle measurement with magnetization inversion method compared with the conventional method based on the assessment of radiofrequency‐decay is that it is free of errors induced by relaxation due to oxygen, by imperfect excitation slice profile and by any diffusion of 3He into and out of the slice. Another advantage is that it does not require image processing with external software and therefore can be performed using the implemented tools on the magnetic resonance workstation. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Mutation in connexin 32 causes charcot–marie–tooth disease in a large Chinese family
Authors: Guo Fuqiang , Shi Yi , Lin Ying , Liu Xiaoqi , Liu Bin , Liu Ying , Yang Yang , Lu Fang , Ma Shi , Yang Zhenglin
Published: September 2010

The purpose was to study the clinical features and genetics of a large Chinese family with Charcot–Marie–Tooth (CMT) disease. A genome‐wide linkage scan using Applied Biosystems v. 2.5 411 short tandem repeat (STR) markers was performed in this family. Mutation screening was conducted on connexin 32 (Cx32). Prediction of impact of the mutation and sequence alignments of Cx32 in 10 vertebrates were performed using Polyphen and Clustal W, respectively. Twelve family members were diagnosed as CMT type 1. An X‐chromosome locus (DXS991) was linked to the phenotype of this family by the genome‐wide linkage analysis. An H100Y mutation found in Cx32 was predicted to be possibly damaging to the function of Cx32, with a PSIC score difference of 1.758. The H100 of Cx32 is highly conserved among the 10 vertebrates. A large Chinese family had CMTX1 linked to Xq13.1 caused by an H100Y mutation in the Cx32 gene. Muscle Nerve, 2010
Diffusion imaging in multiple sclerosis: research and clinical implications
Authors: Inglese M. , Bester Maxim
Published: September 2010

Multiple sclerosis (MS) is an inflammatory‐demyelinating and neurodegenerative disease of the central nervous system (CNS) and the most frequent cause of non‐traumatic disability in young and middle‐age adults. Although conventional MRI (including T2‐weighted, pre‐ and post‐contrast T1‐weighted scans) has had a huge impact on MS by enabling an earlier diagnosis, and by providing surrogate markers for monitoring treatment response, it is limited by the low pathological specificity and the low sensitivity to diffuse damage in normal‐appearing white matter and gray matter. Diffusion weighted MRI is a quantitative technique able to overcome these limitations by providing markers more specific to the underlying pathologic substrates and more sensitive to the full extent of ‘occult’ brain tissue damage. This review describes diffusion studies in MS, discusses their pathophysiological implications and emphasizes their clinical relevance. Copyright © 2010 John Wiley & Sons, Ltd.
Incremental incomplete LU factorizations with applications
Authors: Calgaro Caterina , Chehab Jean‐Paul , Saad Yousef
Published: September 2010

This paper addresses the problem of computing preconditioners for solving linear systems of equations with a sequence of slowly varying matrices. This problem arises in many important applications. For example, a common situation in computational fluid dynamics, is when the equations change only slightly, possibly in some parts of the physical domain. In such situations it is wasteful to recompute entirely any LU or ILU factorizations computed for the previous coefficient matrix. A number of techniques for computing incremental ILU factorizations are examined. For example we consider methods based on approximate inverses as well as alternating techniques for updating the factors L and U of the factorization. Copyright © 2010 John Wiley & Sons, Ltd.
Adaptive dynamic cohesive fracture simulation using nodal perturbation and edge‐swap operators
Authors: Paulino Glaucio H. , Park Kyoungsoo , Celes Waldemar , Espinha Rodrigo
Published: September 2010

Dependence on mesh orientation impacts adversely the quality of computational solutions generated by cohesive zone models. For instance, when considering crack propagation along interfaces between finite elements of 4k structured meshes, both extension of crack length and crack angle are biased according to the mesh configuration. To address mesh orientation dependence in 4k structured meshes and to avoid undesirable crack patterns, we propose the use of nodal perturbation (NP) and edge‐swap (ES) topological operation. To this effect, the topological data structure TopS (Int. J. Numer. Meth. Engng 2005; 64: 1529–1556), based on topological entities (node, element, vertex, edge and facet), is utilized so that it is possible to access adjacency information and to manage a consistent data structure in time proportional to the number of retrieved entities. In particular, the data structure allows the ES operation to be done in constant time. Three representative dynamic fracture examples using ES and NP operators are provided: crack propagation in the compact compression specimen, local branching instability, and fragmentation. These examples illustrate the features of the present computational framework in simulating a range of physical phenomena associated with cracking. Copyright © 2010 John Wiley & Sons, Ltd.
A multiple level set approach to prevent numerical artefacts in complex microstructures with nearby inclusions within XFEM
Authors: Tran A. B. , Yvonnet J. , He Q‐C. , Toulemonde C. , Sanahuja J.
Published: September 2010

In this paper, we highlight that when the extended finite element method (XFEM) is employed to model a microstructure in which inclusions are involved and the distance between two inclusions is small enough to be comparable with the mesh size, three numerical artefacts are induced, significantly affecting the convergence and accuracy of the numerical solution to the problem with such a microstructure. These artefacts are: (a) an artificial percolation of nearby inclusions; (b) an artificial distortion of phase domains; and (c) an enrichment deficiency. We propose to improve the XFEM/Level set method so as to avoid these artefacts. The new technique leading to this improvement uses one level set function for each inclusion and adds additional enrichment in an element whose support is cut by several interfaces. A local description of the multiple level sets is provided to avoid the storage of all level set functions. A simple integration rule is employed for numerical quadrature in elements cut by several interfaces. We show that the artefacts mentioned hereinbefore are circumvented in this framework. The performances of the method are demonstrated through benchmarks and examples applied to the homogenization of concrete materials in 2D and 3D cases. Copyright
© 2010 John Wiley & Sons, Ltd.
Numerical methods for improved efficiency in macrosegregation modeling
Authors: Sajja Udaya K. , Felicelli Sergio D. , Heinrich Juan C.
Published: September 2010

New algorithms developed for the simulation of macrosegregation in directionally solidified alloys are presented. The work has been motivated by the inefficiency of models that have been used in the past. Three different developments are reported, the use of a fractional step projection finite element method to solve the momentum equations, the use of mesh‐less element free Galerkin formulations, and the combination of the Galerkin finite element method with adaptive mesh refinement. The formulation of the different algorithms is given and a two‐dimensional example of application in which the efficiency of the methods is compared is presented. The results of a three‐dimensional calculation using the Galerkin finite element method show that very significant gains are effected when compared with previously published simulations. Copyright © 2010 John Wiley & Sons, Ltd.
On the long time simulation of the Rayleigh–Taylor instability
Authors: Lee Hyun Geun , Kim Kyoungmin , Kim Junseok
Published: September 2010

We investigate the classical Rayleigh–Taylor instability with a phase‐field method. Despite of the long history of numerical simulations for the Rayleigh–Taylor instability, almost all results were relatively short time experiments. This is partly because of the way of treating the pressure boundary conditions. We implement a time‐dependent pressure boundary condition through a time‐dependent density field at the boundary. Owing to the pressure boundary treatment, we can perform long time evolutions resulting in an equilibrium state. In addition to the bubble and spike fronts, we have found that the width of sides is another important landmark on the interface of the Rayleigh–Taylor instability. Copyright © 2010 John Wiley & Sons, Ltd.
Direct estimation of generalized stress intensity factors using a three‐scale concurrent multigrid X‐FEM
Authors: Passieux J. C. , Gravouil A. , Réthoré J. , Baietto M. C.
Published: September 2010

A concurrent multigrid method is devised for the direct estimation of stress intensity factors and higher‐order coefficients of the elastic crack tip asymptotic field. The proposed method bridges three characteristic length scales that can be present in fracture mechanics: the structure, the crack and the singularity at the crack tip. For each of them, a relevant model is proposed. First, a truncated analytical reduced‐order model based on Williams' expansion is used to describe the singularity at the tip. Then, it is coupled with a standard extended finite element (FE) method model which is known to be suitable for the scale of the crack. A multigrid solver finally bridges the scale of the crack to that of the structure for which a standard FE model is often accurate enough. Dedicated coupling algorithms are presented and the effects of their parameters are discussed. The efficiency and accuracy of this new approach are exemplified using three benchmarks. Copyright © 2010 John Wiley & Sons, Ltd.
A partly and fully cracked triangular XFEM element for modeling cohesive fracture
Authors: Mougaard J. F. , Poulsen P. N. , Nielsen L. O.
Published: September 2010

This paper discusses the build‐up of a partly cracked cohesive crack tip element. The crack tip element is based on the principles of the eXtended Finite Element Method (XFEM) and is of Linear Strain Triangle (LST) type. The composition of the enrichment has been in focus to achieve as complete a description as possible on both sides of the crack. The stress accuracy within the crack tip element has been improved to a level, so that the crack tip stresses can be evaluated locally without introducing nonlocal averaging in the surroundings of the crack tip. The partly cracked element can also be applied as a fully cracked element with a few restrictions in the displacement field. The performance of the developed element has been tested in three examples. One example is an infinite sheet with an initial flaw in pure tension, where a semianalytical solution exists. The two other examples are the two benchmark tests: Three‐point Bending Test (TPBT) and the Four‐point Shear Beam (FPSB). The partly cracked element performs well, and captures the overall structural response even for coarse meshes in all the three examples. Copyright © 2010 John Wiley & Sons, Ltd.
A fourth‐order compact scheme for the Helmholtz equation: Alpha‐interpolation of FEM and FDM stencils
Authors: Nadukandi Prashanth , Oñate Eugenio , Garcia Julio
Published: September 2010

We propose a fourth‐order compact scheme on structured meshes for the Helmholtz equation given by R(φ):=f(x)+Δφ+ξ2φ=0. The scheme consists of taking the alpha‐interpolation of the Galerkin finite element method and the classical central finite difference method. In 1D, this scheme is identical to the alpha‐interpolation method (J. Comput. Appl. Math. 1982; 8(1):15–19) and in 2D making the choice α=0.5 we recover the generalized fourth‐order compact Padé approximation (J. Comput. Phys. 1995; 119:252–270; Comput. Meth. Appl. Mech. Engrg 1998; 163:343–358) (therein using the parameter γ=2). We follow (SIAM Rev. 2000; 42(3):451–484; Comput. Meth. Appl. Mech. Engrg 1995; 128:325–359) for the analysis of this scheme and its performance on square meshes is compared with that of the quasi‐stabilized FEM (Comput. Meth. Appl. Mech. Engrg 1995; 128:325–359). In particular, we show that the relative phase error of the numerical solution and the local truncation error of this scheme for plane wave solutions diminish at the rate O((ξℓ)4), where ξ, ℓ represent the wavenumber and the mesh size, respectively. An expression for the parameter α is given that minimizes the maximum relative phase error in a sense that will be explained in Section 4.5. Convergence studies of the error in the L2 norm, the H1 semi‐norm and the l∞ Euclidean norm are done and the pollution effect is found to be small. Copyright © 2010 John Wiley & Sons, Ltd.
Non‐smooth monotonicity constraints in optimal control problems: Some economic applications
Authors: Ruiz del Portal X.
Published: September 2010

This paper presents a theorem on necessary conditions for optimal control problems containing monotonicity constraints that bear on a joint function of the control variable, the state variable, and the time. These constraints are often found, under continuity and piecewise smoothness assumptions for the endogenous variables of the problem, in various economic fields that include monopoly regulation, non‐uniform pricing, implicit contracts, and optimal taxation. After applying our theorem to a general incentive provision model, we show its usefulness in relaxing the standard continuity and smoothness assumptions, for the case of two screening problems among those that have received more attention in the literature. Copyright © 2010 John Wiley & Sons, Ltd.
A modified pseudospectral scheme for accurate solution of Bang‐Bang optimal control problems
Authors: Shamsi M.
Published: September 2010

In the present contribution, a modified Legendre pseudospectral scheme for accurate and efficient solution of bang‐bang optimal control problems is investigated. In this scheme control and state functions are considered as piecewise constant and piecewise continuous polynomials, respectively, and the switching points are also taken as decision variables. Furthermore, for simplicity in discretization, the integral formulation of the dynamical equations is considered. Thereby, the problem is converted into a mathematical programming problem which can be solved by the well‐developed parameter optimization algorithms. The main advantages of the present method are that: (i) it obtains good results even by using a small number of collocation points and the rate of convergence is high; (ii) the switching times can be captured accurately; and (iii) the wrongly chosen number of switching points can be detected by the results of the method. These are illustrated through a numerical implementation of the method on three examples and the efficiency of the method is reported. Copyright © 2010 John Wiley & Sons, Ltd.
GRP78 up‐regulation is associated with androgen receptor status, Hsp70–Hsp90 client proteins and castrate‐resistant prostate cancer
Authors: Tan Shaun S , Ahmad Imran , Bennett Haley L , Singh Lukram , Nixon Colin , Seywright Morag , Barnetson Robert J , Edwards Joanne , Leung Hing Y
Published: September 2010

GRP78/BiP is a key member of the molecular chaperone heat shock protein (Hsp) 70 family. It has a critical role in prostate cancer (PC) includingPtenloss‐driven carcinogenesis, but the molecular basis of this remains unclear. We investigated the effect of GRP78 and its putative client proteins, including androgen receptor (AR) in clinical PC. Expression of GRP78 and key Hsp70–hsp90 client proteins (HER2, HER3, AR and AKT) were studied in an incidence tissue microarray (TMA) of prostate cancer. The relationship of GRP78 and AR was further tested inin vitrocell models (LNCaP and its derived LNCaP‐CR subclone) and a matched TMA of hormone‐naïve (HNPC) and castrate‐resistant prostate cancer (CRPC).In vitroandin vivoexpression of GRP78 and client proteins were assessed by western blotting and immunohistochemistry, respectively, using the weighted histoscore method. Significant co‐expression of GRP78, pAKT, HER2, HER3 and AR was observed in PC. Abnormal AR, GRP78 and pAKT expression have significant impact on patient survival. GRP78 expression in AR+tumours was significantly higher than in AR−tumours. In keeping with our clinical data, activation of AR by dihydrotestosterone (DHT) potently activated GRP78 expression in both LNCaP and LNCaP‐CR cells. For the first time, using a matched HNPC and CRPC TMA, enhanced cytoplasmic and membranous GRP78 expression was observed in CRPC. Future prospective studies are therefore warranted to validate GRP78 as prognostic marker and therapeutic target, in the context of the AR and pAKT status. In summary, GRP78 is co‐expressed with Hsp70–hsp90 client proteins. Up‐regulated expression of AR and GRP78 expression in untreated prostate cancer predicts a less favourable outcome. This points to the importance of understanding in the molecular interaction among AR, GRP78 and AKT. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Current awareness: Pharmacoepidemiology and drug safety
Authors:   John Wiley & Sons, Ltd.
Published: September 2010

In order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of pharmacoepidemiology and drug safety. Each bibliography is divided into 23 sections: 1 Reviews; 2 General; 3 Anti‐infective Agents; 4 Cardiovascular System Agents; 5 CNS Depressive Agents; 6 Non‐steroidal Anti‐inflammatory Agents; 7 CNS Agents; 8 Anti‐neoplastic Agents; 9 Haematological Agents; 10 Neuroregulator‐Blocking Agents; 11 Dermatological Agents; 12 Immunosuppressive Agents; 13 Autonomic Agents; 14 Respiratory System Agents; 15 Neuromuscular Agents; 16 Reproductive System Agents; 17 Gastrointestinal System Agents; 18 Anti‐inflammatory Agents ‐ Steroidal; 19 Teratogens/fetal exposure; 20 Antidiabetic Agents; 21 Contrast Agents; 22 Bone Conservation Agents; 23 Others. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.
Gamma radiation on poly(ϵ‐caprolactone) in the presence of vinyltrimethoxysilane
Authors: Wang Shusheng , Han Changyu , Han Lijing , Wang Xuemei , Bian Junjia , Zhuang Yugang , Dong Lisong
Published: September 2010

The performance and radiation‐induced cross‐linking of polycaprolactone (PCL) in the presence of vinyltrimethoxysilane (VTMS) have been investigated. Radiation‐induced cross‐linking of PCL in the presence of VTMS followed the Charlesby–Pinner equation, and VTMS promoted the radiation‐induced cross‐linking of PCL. As the concentration of VTMS increased, the gelation dose and the ratio of degradation to cross‐linking (p0/q0) decreased and the efficiency of radiation‐induced cross‐linking increased. Differential scanning calorimetry analyses showed differences between the first and second scans. Glass‐transition temperature (Tg) and mechanical properties of the polymers increased. Radiation‐induced cross‐linking of PCL in the presence of VTMS was found to retard hydrolytic degradation greatly. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
A confirmatory factor analysis of the Stanford–Binet Intelligence Scales, Fifth Edition, with a high‐achieving sample
Authors: Williams Tasha H. , McIntosh David E. , Dixon Felicia , Newton Jocelyn H. , Youman Elizabeth
Published: September 2010

The Stanford–Binet Intelligence Scale, Fifth Edition (SB5), is a recently published, multidimensional measure of intelligence based on Cattell–Horn–Carroll (CHC) theory. The author of the test provides results from confirmatory factor analyses in the technical manual supporting the five‐factor structure of the instrument. Other authors have examined this factor structure through EFA using the standardization sample, and have not found evidence of a five‐factor model. The purpose of the current study was to examine the internal construct validity of the SB5 using an independent sample of high‐functioning students. Participants included 201 high‐functioning, third‐grade students ranging in age from 8 years, 4 months to 10 years, 11 months. Five models of the SB5 were analyzed using Analysis of Moment Structures (AMOS). Our findings indicated that a hierarchical, four‐factor, post‐hoc model provided the best fit to the data. Generally, implications for school psychologists include a better understanding of the factor structure of the SB5, especially as it relates to high‐achieving children. Directions for future research are also discussed. © 2010 Wiley Periodicals, Inc.
Words correct per minute: The variance in standardized reading scores accounted for by reading speed
Authors: Williams Jacqueline L. , Skinner Christopher H. , Floyd Randy G. , Hale Andrea D. , Neddenriep Christine , Kirk Emily P.
Published: September 2010

The measure words correct per minute (WC/M) incorporates a measure of accurate aloud word reading and a measure of reading speed. The current article describes two studies designed to parse the variance in global reading scores accounted for by reading speed. In Study I, reading speed accounted for more than 40% of the reading composite score variance in 4th‐, 5th‐, and 10th‐grade students. In Study II, reading speed accounted for more than 30% of the reading/language arts composite score variance of fourth‐ and fifth‐grade students. Across both studies, when reading speed was combined with words read correctly and converted to WC/M the additional variance accounted for was less than 10% with one exception, fourth‐grade students' reading/language arts scores. These findings are consistent with various theories regarding reading speed, provide direction for future researchers, and may assuage those concerned that WC/M is primarily a measure of aloud, accurate word reading (i.e., word calling). © 2010 Wiley Periodicals, Inc.
Novel synthesis of 2‐aminoquinoline‐3‐carbaldehyde, benzo[b][1,8]naphthyridines and study of their fluorescence behavior
Authors: Shelar Deepak P. , Birari Dilip R. , Rote Ramhari V. , Patil Sandeep R. , Toche Raghunath B. , Jachak Madhukar N.
Published: September 2010

A novel route was successfully developed for the synthesis of new synthons, orthoamino formyl quinoline (heterocyclic orthoaminoaldehyde) and utilized for the synthesis of series of benzonaphthyridines by Friedländer condensation reactions with benzoylacetonitrile. The benzonaphthyridines synthesized were further studied for their fluorescence properties. Copyright © 2010 John Wiley & Sons, Ltd.
Photostability of D–π–A nonlinear optical chromophores containing a benzothiazolium acceptor
Authors: Cigáň Marek , Gáplovský Anton , Sigmundová Ivica , Zahradník Pavol , Dĕdic Roman , Hromadová Magdaléna
Published: September 2010

For the practical application of second‐order NLO materials, not only a high molecular quadratic hyperpolarizability β but also good thermal, chemical, and photochemical stabilities are required. Most of the state‐of‐the‐art chromophores with high NLO response cannot be put to use because they are photochemically highly unstable. Good thermal and photochemical stabilities with preserved high hyperpolarizabilities can be achieved by replacement of an aromatic ring with easily delocalizable heteroaromatics, e.g., with benzothiazole. Furthermore, desirable modifications of the benzothiazole fragment lead to improvement in β values. Here we report results of a comprehensive investigation of the photochemical stability of seven D–π–A push–pull molecules based on a N‐methylbenzothiazolium acceptor and a N,N‐dimethylaminophenyl donor with a different length of conjugated bridge and different acceptor strength. The quantum yield (Φ) and the kinetic parameters of photoreactions were determined for existing photodegradation pathways on irradiation at 300–850 nm in MeOH. Trans–cis photoisomerization is proposed as a fast but inefficient photobleaching mechanism for these irradiation wavelengths. Self‐sensitized photooxidation by 1O2 makes very slow parallel photodegradation pathway and, albeit to small value of Φ, plays a dominant role in the photodegradation of the compounds investigated. Both structural modifications (extension of conjugated bridge and an additional acceptor group bonded to heterocycle) resulting in an increase of NLO response led to a decrease in photostability due to the self‐sensitized 1O2 photooxidative attack. Thus a compromise should be found between an increase in NLO response and a decrease in photostability to make a choice of studied compounds for practical applications. Copyright © 2010 John Wiley & Sons, Ltd.
Nonlinear rheology of model filled elastomers
Authors: Papon Aurélie , Montes Hélène , Lequeux François , Guy Laurent
Published: September 2010

Submitted to large sinusoidal strains, filled elastomers not only show a decrease in their storage modulus — the Payne effect, but also a nonlinear behavior — their response is not sinusoidal anymore and involves strain‐stiffening. We show in this study that the two effects can be separated thanks to large amplitude oscillatory shear experiments. The stress signal of filled elastomers consisting of a dispersion of silica particles into a polymeric matrix was decomposed into an elastic and a viscous part and we could observe simultaneously the Payne effect and a strain‐stiffening phenomenon. We showed that the strain‐stiffening was correlated with the Payne effect but came from various intricated effects. It most probably also has its origins in the finite extensibility of the polymer chains confined between solid particles, where the strain is larger. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010