bluuebunny/crossref_metadata_2025 huggingface dataset:
Safety and effectiveness of drug eluting stent in patients with ST elevation myocardial infarction undergoing primary angioplasty
Authors: Romano Michele , Buffoli Francesca , Tomasi Luca , Corrado Lettieri , Ferrari Maria Rosa , Zanini Roberto
Published: April 2008

Background: Drug eluting stents (DES) have recently been proven to further reduce restenosis and revascularization rate in comparison to bare metal stents in elective procedures. Most early DES trials did not include patients undergoing primary percutaneous coronary intervention (PCI) for ST‐segment elevation MI, because these patients tend to have lower restenosis rates than other patient groups and delayed endothelization of these stents raises concern about a possible increase of thrombotic complications in the setting of STEMI. Aim: To confirm the safety and effectiveness of DES in patients with STEMI in a real‐world scenario. Methods: From January 2004 to December 2006, clinical and angiographic data of 370 patients with STEMI treated with primary PCI have been analyzed. Patients were retrospectively followed for the occurrence of major adverse cardiac events (MACE): death, reinfarction and target vessel revascularization (TVR). Results: Overall, 120 patients received DES (32%, DES group) and 250 received bare metal stents (68%, BMS group) in the infarct related artery. Compared with the BMS group, DES patients were younger, (mean age 56 ± 12 vs. 65 ± 10; P < 0.001) had more often diabetes mellitus (47% vs. 14% P < 0.001), anterior localization (65% vs. 45%; P < 0.0011) and less cardiogenic shock at admission (4% vs. 7%; P < 0.001). The angiographic characteristics in the DES group showed longer lesions (23 mm vs. 19 mm) and smaller diameter of vessels (2.5 mm vs. 3.0 mm). After a median follow‐up of 24 ± 9 months, there was no significant difference in the rate of stent thrombosis (1.6% in the DES group vs. 1.2% in the BMS group, P = ns). The incidence of MACE was significantly lower in the DES group compared with the BMS group (HR 0.56 [95% CI: 0.3–0.8]; P = 0.01), principally due to the lower rate of TVR (HR 0.41 [95% CI: 0.2–0.85]; P = 0.01). Conclusions: Utilization of DES in the setting of primary PCI for STEMI, in our “real world,” was safe and improved the 3‐year clinical outcome compared with BMS reducing the need of TVR. © 2008 Wiley‐Liss, Inc.
Sloshing analysis of a liquid storage container using level set X‐FEM
Authors: Nagashima Toshio
Published: April 2008

The extended finite element method (X‐FEM), in conjunction with the level set method, is applied to sloshing analysis of a rigid container filled with liquid. The governing equations for liquid with a free surface based on the potential flow theory are discretized using the framework of level set X‐FEM. Once the space domain of a container is modeled by tetrahedral elements, sloshing analysis for arbitrary liquid levels and configurations can be performed without remeshing. Natural frequencies of free surface sloshing motion in rigid containers of various shapes were computed by the proposed method and the results were compared with those obtained by theoretical solutions and experiments. The proposed method was demonstrated to perform sloshing analysis efficiently for rigid containers with various liquid levels and configurations. Copyright © 2008 John Wiley & Sons, Ltd.
Control of gastrula cell motility by the Goosecoid/Mix.1/ Siamois network: Basic patterns and paradoxical effects
Authors: Luu Olivia , Nagel Martina , Wacker Stephan , Lemaire Patrick , Winklbauer Rudolf
Published: April 2008

In the vegetal half of the Xenopus gastrula, cell populations differ with respect to migration on fibronectin substratum. We show that the paired‐class homeodomain transcription factors Goosecoid (Gsc), Mix.1, and Siamois (Sia) are involved in the modulation of migration velocity and cell polarity. Mix.1 is expressed in the whole vegetal half and serves as a competence factor that is necessary, but not sufficient, for rapid cell migration and polarization. In the head mesoderm, Gsc and Sia are coexpressed with Mix.1, promoting rapid cell migration and polarization. Ectopic expression of Gsc and Sia in both vegetal and ventral regions often generates paradoxical effects; if a factor activates a certain motility trait in one region, it inhibits it in the other. Migration velocity and cell polarity are regulated independently. Fast and efficiently migrating multipolar cells and slow‐moving polarized cells can be obtained by ectopic expression of these transcription factors in different combinations. Developmental Dynamics 237:1307‐1320, 2008. © 2008 Wiley‐Liss, Inc.
Novel structure of three‐phase phase‐locked loop with robustness against disturbances
Authors: Bae Byung Y. , Han Byung M.
Published: April 2008

Phase‐locked loop (PLL) is a key item to control power converters for power conditioning system and power quality compensator. This paper proposes a novel structure of three‐phase PLL that is composed of adaptive linear combiner (ALC) and proportional integral (PI) control. The operational principle was investigated through theoretical approach. The performance was verified through computer simulations with MATLAB and experimental works with TMS320vc33 digital signal processor (DSP) board. The three‐phase PLL shows accurate performance under the voltage disturbances such as sag, harmonics, and phase‐angle jump. Copyright © 2008 John Wiley & Sons, Ltd.
Novel DLC model for QoS enhancement of bursty VBR traffic in wireless ATM networks
Authors: El‐Ocla Hosam , El. Tobely Tarek E.
Published: April 2008

Several data‐link control (DLC) protocol procedures have been proposed in order to provide reliable data transmission over powerless radio links. However, many quality of service (QoS) issues still need to be achieved such as balance between cell transfer delay (CTD) and cell loss rate (CLR), absence of cell delay variation (CDV) and network traffic utilisation. The main problem with wireless ATM is how to overcome the unreliability of the wireless link in order to maintain QoS requirements especially for variable bit rate (VBR) application. Here, we propose a model that provides QoS support for ATM virtual connections (VC) and solves the unreliability problem of the wireless ATM through an efficient DLC protocol for bursty VBR traffic. This model mainly concerns with enhancing QoS to gain error‐free wireless transmission and regulating VBR Traffic. Copyright © 2008 John Wiley & Sons, Ltd.
First‐ and second‐order sensitivity equation methods for value and shape parameters
Authors: Ilinca F. , Pelletier D. , Hay A.
Published: April 2008

This paper presents formulations of the sensitivity equation method (SEM) and applications to transient flow problems. Solutions are shown for both value and shape parameters using a three‐dimensional solution algorithm. Sensitivities are used for fast evaluation of the flow at nearby values of the parameters: the solution is approximated by a Taylor series in parameter space involving the flow sensitivities. The accuracy of nearby flows is much improved when second‐order sensitivities are used. We show how the sensitivity of the Strouhal number can be obtained from the flow sensitivities. Results are in agreement with the experimental correlation. The methodology is also applied to the flow past a cylinder in ground proximity. The proposed method is verified on a steady‐state problem by comparing the computed sensitivity with the actual change in the solution when a small perturbation is imposed on the shape parameter. We then investigate the ability of the SEM to anticipate the unsteady flow response to changes in the ground to cylinder gap. The approach properly reproduces the damping or amplification of the vortex shedding with a reduction or increase of the gap size. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Implicit symmetrized streamfunction formulations of magnetohydrodynamics
Authors: Kang K. S. , Keyes D. E.
Published: April 2008

We apply the finite element method to the classic tilt instability problem of two‐dimensional, incompressible magnetohydrodynamics, using a streamfunction approach to enforce the divergence‐free conditions on the magnetic and velocity fields. We compare two formulations of the governing equations, the standard one based on streamfunctions and a hybrid formulation with velocities and magnetic field components. We use a finite element discretization on unstructured meshes and an implicit time discretization scheme. We use the PETSc library with index sets for parallelization. To solve the nonlinear problems on each time step, we compare two nonlinear Gauss‐Seidel‐type methods and Newton's method with several time‐step sizes. We use GMRES in PETSc with multigrid preconditioning to solve the linear subproblems within the nonlinear solvers. We also study the scalability of this simulation on a cluster. Copyright © 2008 John Wiley & Sons, Ltd.
A Taylor series‐based finite volume method for the Navier–Stokes equations
Authors: Wu G. X. , Hu Z. Z.
Published: April 2008

A Taylor series‐based finite volume formulation has been developed to solve the Navier–Stokes equations. Within each cell, velocity and pressure are obtained from the Taylor expansion at its centre. The derivatives in the expansion are found by applying the Gauss theorem over the cell. The resultant integration over the faces of the cell is calculated from the value at the middle point of the face and its derivatives, which are further obtained from a higher order interpolation based on the values at the centres of two cells sharing this face. The terms up to second order in the velocity and the terms up to first order in pressure in the Taylor expansion are retained throughout the derivation. The test cases for channel flow, flow past a circular cylinder and flow in a collapsible channel have shown that the method is quite accurate and flexible. Copyright © 2008 John Wiley & Sons, Ltd.
Enhancement of fixed‐grid methods towards complex fluid–structure interaction applications
Authors: Gerstenberger Axel , Wall Wolfgang A.
Published: April 2008

Fixed‐grid methods for moving interface problems offer a number of attractive properties and have therefore gained quite some popularity in recent time. However, moving mesh approaches still have their advantages when the physical problem requires special treatment or accurate representation of the interface. This is, for example, the case in complex fluid–structure interaction (FSI) problems when state‐of‐the‐art boundary layer meshing is essential. This paper explores two enhancements of fixed‐grid methods that allow the improved solution of such complex FSI problems. The two enhancements are a straightforward approach based on local adaptivity and a hybrid method that combines ideas from fixed‐grid methods and arbitrary Lagrangean–Eulerian formulations. Although both enhancements could be used with most available fixed‐grid approaches they are given here against the background of a recently developed extended finite element method (XFEM)/Lagrange multiplier (LM) (Comp. Meth. Appl. Mech. Eng. 2007. DOI: 10.1016/j.cma.2007.07.002) fixed‐grid method. It is shown that the hybrid scheme perfectly fits into the presented XFEM/LM framework in a consistent way. Copyright © 2008 John Wiley & Sons, Ltd.
Blood flow dynamics and fluid–structure interaction in patient‐specific bifurcating cerebral aneurysms
Authors: Valencia Alvaro , Ledermann Darren , Rivera Rodrigo , Bravo Eduardo , Galvez Marcelo
Published: April 2008

Hemodynamics plays an important role in the progression and rupture of cerebral aneurysms. The current work describes the blood flow dynamics and fluid–structure interaction in seven patient‐specific models of bifurcating cerebral aneurysms located in the anterior and posterior circulation regions of the circle of Willis. The models were obtained from 3D rotational angiography image data, and blood flow dynamics and fluid–structure interaction were studied under physiologically representative waveform of inflow. The arterial wall was assumed to be elastic, isotropic and homogeneous. The flow was assumed to be laminar, non‐Newtonian and incompressible. In one case, the effects of different model suppositions and boundary conditions were reported in detail. The fully coupled fluid and structure models were solved with the finite elements package ADINA. The vortex structure, pressure, wall shear stress (WSS), effective stress and displacement of the aneurysm wall showed large variations, depending on the morphology of the artery, aneurysm size and position. The time‐averaged WSS, effective stress and displacement at the aneurysm fundus vary between 0.17 and 4.86 Pa, 4.35 and 170.2 kPa and 0.16 and 0.74 mm, respectively, for the seven patient‐specific models of bifurcating cerebral aneurysms. Copyright © 2008 John Wiley & Sons, Ltd.
Convergence of MPFA on triangulations and for Richards' equation
Authors: Klausen R. A. , Radu F. A. , Eigestad G. T.
Published: April 2008

Spatial discretization of transport and transformation processes in porous media requires techniques that handle general geometry, discontinuous coefficients and are locally mass conservative. Multi‐point flux approximation (MPFA) methods are such techniques, and we will here discuss some formulations on triangular grids with further application to the nonlinear Richards equation. The MPFA methods will be rewritten to mixed form to derive stability conditions and error estimates. Several MPFA versions will be shown, and the versions will be discussed with respect to convergence, symmetry and robustness when the grids are rough. It will be shown that the behavior may be quite different for challenging cases of skewness and roughness of the simulation grids. Further, we apply the MPFA discretization approach for the Richards equation and derive new error estimates without extra regularity requirements. The analysis will be accompanied by numerical results for grids that are relevant for practical simulation. Copyright © 2008 John Wiley & Sons, Ltd.
Stabilized finite element methods to predict ventilation efficiency and thermal comfort in buildings
Authors: Lube G. , Knopp T. , Rapin G. , Gritzki R. , Rösler M.
Published: April 2008

The non‐isothermal, incompressible Navier–Stokes equations with Boussinesq approximation are considered as a model of turbulent indoor air flows. The transient calculation is based on the Reynolds‐averaged Navier–Stokes problem using the k/ε‐turbulence model or improved variants such as the $\overline{v^2}-f$ model. The model is first discretized in time using backward‐differencing schemes and then linearized using a Newton‐type method per time step with emphasis on the proper calculation of (non‐negative) turbulence quantities. The resulting auxiliary problems of Oseen type and of advection–diffusion–reaction type are solved using stabilized finite element method of residual type. Here we summarize some of our recent analytical results for higher‐order methods and shock‐capturing techniques. The numerical solution to the model in boundary layer regions is obtained using either adaptive wall functions if the k‐ε model is used or a hybrid mesh with anisotropic refinement if the $\overline{v^2}-f$ model is applied. Besides the standard flow quantities, it is possible to calculate quantities such as the age of the air. Such quantities are used to develop criteria for the evaluation of the efficiency of air exchange in a room. The quality of the numerical simulations is demonstrated for typical benchmark problems. Copyright © 2008 John Wiley & Sons, Ltd.
A vortex axis and vortex core border grid adaptation algorithm
Authors: Rütten Markus , Alrutz Thomas , Wendland Holger
Published: April 2008

In the design process of hydrodynamical and aerodynamical technical applications, the numerical simulation of massively separated vortical flow is crucial for predicting, for example, lift or drag. To obtain reliable numerical results, it is mandatory to accurately predict the physical behavior of vortices. Thus, the dominant vortical flow structures have to be resolved in detail, which requires a local grid refinement and certain adaptation techniques. In this paper, a vortex flow structure adaptation algorithm is presented, which is particularly designed for local grid refinement at vortex axes positions and associated vortex core border locations. To this end, a fast and efficient vortex axis detection scheme is introduced and the algorithm for the vortex core border determination is explained. As the interaction between vortices makes the assignment of grid points to a certain vortex axis difficult, a helicity‐based vortex distinction approach in combination with a geometrical rotational sensor is developed. After describing the combined different techniques in detail, the vortex feature adaptation algorithm is applied to analytical and more realistic examples, which show that the described grid adaptation algorithm is able to enhance the grid cell resolution locally such that all significant vortical flow phenomena are resolved. Copyright © 2008 John Wiley & Sons, Ltd.
Energy norm a posteriori error estimation for divergence‐free discontinuous Galerkin approximations of the Navier–Stokes equations
Authors: Kanschat Guido , Schötzau Dominik
Published: April 2008

We develop the energy norm a posteriori error analysis of exactly divergence‐free discontinuous RTk/Qk Galerkin methods for the incompressible Navier–Stokes equations with small data. We derive upper and local lower bounds for the velocity–pressure error measured in terms of the natural energy norm of the discretization. Numerical examples illustrate the performance of the error estimator within an adaptive refinement strategy. Copyright © 2008 John Wiley & Sons, Ltd.
On the use of anisotropic a posteriori error estimators for the adaptative solution of 3D inviscid compressible flows
Authors: Bourgault Y. , Picasso M. , Alauzet F. , Loseille A.
Published: April 2008

This paper describes the use of an a posteriori error estimator to control anisotropic mesh adaptation for computing inviscid compressible flows. The a posteriori error estimator and the coupling strategy with an anisotropic remesher are first introduced. The mesh adaptation is controlled by a single‐parameter tolerance (TOL) in regions where the solution is regular, whereas a condition on the minimal element size hmin is enforced across solution discontinuities. This hmin condition is justified on the basis of an asymptotic analysis. The efficiency of the approach is tested with a supersonic flow over an aircraft. The evolution of a mesh adaptation/flow solution loop is shown, together with the influence of the parameters TOL and hmin. We verify numerically that the effect of varying hmin is concordant with the conclusions of the asymptotic analysis, giving hints on the selection of hmin with respect to TOL. Finally, we check that the results obtained with the a posteriori error estimator are at least as accurate as those obtained with anisotropic a priori error estimators. All the results presented can be obtained using a standard desktop computer, showing the efficiency of these adaptative methods. Copyright © 2008 John Wiley & Sons, Ltd.
Assessment of algorithms for the no‐slip boundary condition in the lattice Boltzmann equation of BGK model
Authors: Suh Yong Kweon , Kang Jinfen , Kang Sangmo
Published: April 2008

Three kinds of algorithms for the lattice Boltzmann equation of the BGK model in the implementation of the no‐slip boundary condition on the wall are assessed by using the analytical formula for the slip velocity of the fully developed pressure‐driven channel flow. It is shown that the bounce‐back algorithm results in the spatial accuracy of 1st order, except for the case when the wall is located at half way between the two grid lines. The interpolation scheme proposed by Yu et al. (Prog. Aerospace Sci. 2003; 39:329–367) and the similar one by Bouzidi et al. (Phys. Fluids 2001; 13(11):3452–3459) are of 2nd order, but the error increases quadratically with the relaxation time. The extrapolation scheme of Guo et al. (Phys. Fluids 2002; 14(6):2007–2010) is also shown to be of 2nd order, and the error level increases linearly with the relaxation time, but it turns out that this scheme is unstable for a certain range of parameter values. Numerical experiments with various parameter sets have been performed to obtain the stability diagram. Three algorithms are then applied to a circular‐Couette flow and their performance is also studied in terms of the numerical accuracy and stability. Copyright © 2008 John Wiley & Sons, Ltd.
Non‐Newtonian flow in branched pipes and artery models
Authors: Barth William L. , Branets Larisa V. , Carey Graham F.
Published: April 2008

This work concerns finite element analysis for a class of generalized Newtonian flows through branching pipe or tube junctions in industrial applications or blood flow through arterial branches, prosthetic tube implants or in biomedical engineering devices. A two‐step morphing transformation is developed and implemented to map a generic coplanar 3D branching flow configuration to general out‐of‐plane deformed geometry including local constriction/dilation ‘defects’ suitable for modeling specific arterial flow and industrial flow applications. Unstructured 3D meshes may be generated in the reference configuration and morphed to the application configuration. The resulting meshes may be tangled and exhibit mesh quality degradation. Algorithms integrating mesh generation, morphing, untangling and cell shape control strategies are presented.

Phenomenological studies are conducted with the Powell–Eyring class as a representative model to determine local details of shear‐thinning flow behavior as well as the nature and location of high shear stress regions on artery branch walls. The supporting simulations are carried out using a parallel finite element scheme with domain decomposition by a sectional partitioning that takes advantage of the medial curve shape and specialized ILU preconditioning. Copyright © 2008 John Wiley & Sons, Ltd.
Steady flow through a realistic human upper airway geometry
Authors: Nithiarasu P. , Hassan O. , Morgan K. , Weatherill N. P. , Fielder C. , Whittet H. , Ebden P. , Lewis K. R.
Published: April 2008

Air flow through a human upper airway (central part) has been carried out using a realistic geometry. In addition to explaining the anatomy, problems and importance of patient‐specific study of human upper airways, this article also presents some qualitative and quantitative simulation results. As expected, the shear and pressure forces are large in the oropharynx and laryngopharynx, where the flow passage is narrow. This clearly indicates that these locations should be the focus of any study aimed at understanding the human upper airway collapse in a patient‐specific manner. Copyright © 2008 John Wiley & Sons, Ltd.
Stress, social support, and outcomes in two probability samples of homeless adults
Authors: Toro Paul A. , Tulloch Elizabeth , Ouellette Nicole
Published: April 2008

This study investigated the main effects of social support measures and their stress‐buffering effects in two samples of homeless adults (Ns=249 and 219) obtained in the same large county (surrounding Detroit) at different points in time over an 8‐year period (1992–1994 and 2000–2002). The findings suggest that the construct of social support, commonly applied to broad community and student samples, can also be usefully applied to at‐risk groups such as the homeless. Although the study's main effects and stress‐buffering effects were generally consistent with existing research on social support, the findings point out that expected results do not consistently emerge even when similar sampling and measurement techniques are employed. For example, a measure of perceived support showed consistent main and stress‐buffering effects on psychological symptoms (but not other outcomes) and social network measures showed less consistent effects on outcomes (e.g., alcohol and drug abuse symptoms). © 2008 Wiley Periodicals, Inc.
Using discourse analysis and psychological sense of community to understand school transitions
Authors: Fyson Stephen J.
Published: April 2008

The research involved examining the nature of the transition that students experienced in progressing to junior high school from primary school. Students' experiences were chosen as the focus of the research because the issue of substance being investigated was that of alienation. The main methodology that was used was the qualitative procedure of discourse analysis, implemented over a 3‐year period. This report describes the findings from the first year of the study.

The key findings of the research include the establishment of critical concerns of students. These critical concerns were articulated as psychological sense of community categories of interest, with positive and negative discourse descriptors being developed according to an analysis of students' descriptions of social regularities. The categories of interest were arranged into a sequential pattern that described pathways to increasing commitment or alienation. © 2008 Wiley Periodicals, Inc.
A commentary on Newbrough's Third Position
Authors: Newbrough J. R. , McMillan David W. , Lorion Raymond P.
Published: April 2008

Newbrough's Third Position is discussed in terms of its utility as a framework within which to understand and resolve interpersonal differences, seemingly irresolvable diametric differences, and conflictual situations. The framework's essential elements and its application is illustrated through the presentation of a series of fictitious scenarios that open with conflict and close with a resolution in which the interested parties feel heard and satisfied. The intent of the commentary is to re‐introduce community psychologists to this framework and encourage its consideration, application, and investigation in responding to community‐based conflicts and the resolution of seeming impasses. The Third Position is presented as a valuable tool for the community psychologist involved with conflict resolution, community consultation, and community development. © 2008 Wiley Periodicals, Inc.
Community involvement and adolescent mental health: moderating effects of race/ethnicity and neighborhood disadvantage
Authors: Hull Pamela , Kilbourne Barbara , Reece Michelle , Husaini Baqar
Published: April 2008

Social development and stress process theories suggest that participation in one's community can function as a protective factor for mental health, especially for youth from socioeconomically disadvantaged areas. However, the effects of community involvement on adolescent mental health could vary across racial/ethnic groups and levels of neighborhood disadvantage. The objectives of this paper are to: (1) examine the effects of various types of community involvement on adolescent mental health, and (2) assess the extent to which race/ethnicity and neighborhood disadvantage moderate the effects of community involvement on adolescent mental health. Using data from two waves (1994/95 and 1996) of the National Longitudinal Study of Adolescent Health (“Add Health,” N=7,863), multilevel (hierarchical) linear models were estimated that tested for interaction effects of race/ethnicity and neighborhood disadvantage. The types of community participation that impacted adolescent mental health varied across racial/ethnic groups. Neighborhood interaction and religious participation were salient for both White and Hispanic teens, but the impact of religious participation for Whites was moderated by neighborhood disadvantage. Non‐sport extracurricular activities and employment were the salient factors for Black teens, both of which were moderated by neighborhood disadvantage. The findings from this study have implications for community‐level and clinical interventions to prevent and/or treat mental health problems among adolescents. Social integration interventions should take into account adolescents' cultural backgrounds and socioeconomic contexts in order to be effective. © 2008 Wiley Periodicals, Inc.
Eucalyptus globulus kraft process modifications: Effect on pulping and bleaching performance and papermaking properties of bleached pulps
Authors: Santiago AS , Neto C Pascoal
Published: April 2008

BACKGROUND: Increasing the yield of the wood pulping process allows the reduction of specific wood costs. Process modifications with a great impact on pulp yield are the profiling of chemical charges and addition of anthraquinone (AQ). The aim of the present work is to investigate the influence of effective alkali (EA) profiling and addition of anthraquinone on E. globulus kraft pulping performance. The impact of such process modifications on the ECF bleaching process and on the papermaking properties of the resulting bleached pulps is also evaluated.

RESULTS: An EA profiling cook may lead to a pulp yield gain, which is more significant as the total EA charge used in the kraft cook increases. AQ addition to kraft pulping leads to a significant yield increase. The ClO2 charge required to fully bleach the pulps is lower for EA profiling and higher for kraft + AQ unbleached pulps. Bleached AQ pulp presents a high beatability due to high pulp xylan retention.

CONCLUSION: A low total EA charge is the key parameter for high polysaccharide retention on pulp. AQ addition constitutes a feasible strategy to increase pulp yield. Bleaching performance and papermaking properties of pulps produced with the three different methods may be affected by the kraft pulping modifications. Copyright © 2008 Society of Chemical Industry
Direct injection LC/ESI‐MS horse urine analysis for the quantification and identification of threshold substances for doping control. I. Determination of hydrocortisone
Authors: Vonaparti A. , Lyris E. , Panderi I. , Koupparis M. , Georgakopoulos C.
Published: April 2008

Two simple and rapid LC/MS methods with direct injection analysis were developed and validated for the quantification and identification of hydrocortisone in equine urine using the same sample preparation but different mass spectrometric systems: ion trap mass spectrometry (IT‐MS) and time‐of‐flight mass spectrometry (TOF‐MS). The main advantage of the proposed methodology is the minimal sample preparation procedure, as particle‐free diluted urine samples were directly injected into both LC/MS systems. Desonide was used as internal standard (IS). The linear range was 0.25–2.5 µg ml−1 for both methods. Matrix effects were evaluated by preparing and analyzing calibration curves in water solutions and different horse urine samples. A great variation of the signal both for hydrocortisone and the internal standard was observed in different matrices. To overcome matrix effects, the unavailability of blank matrix and the excessive cost of the isotopically labeled internal standard, standard additions calibration method was applied. This work is an exploration of the performance of the standard additions approach in a method where neither nonisotopic internal standards nor extensive sample preparation is utilized and no blank matrix is available. The relative standard deviations of intra and interday analysis of hydrocortisone in horse urine were lower than 10.2 and 5.4%, respectively, for the LC/IT‐MS method and lower than 8.4 and 4.4%, respectively, for the LC/TOF‐MS method. Accuracy (bias percentage) was less than 9.7% for both methods. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of lyophilisation, refrigerated storage and frozen storage on the coagulant activity and microbiological quality of Cynara cardunculus L. extracts
Authors: Tejada Luis , Vioque Montserrat , Gómez Rafael , Fernández‐Salguero José
Published: April 2008

BACKGROUND:Cheese‐makers have traditionally kept vegetable coagulants refrigerated until use, even though little was known of their microbiological quality or coagulant activity during storage. This study aimed to assess the efficacy of lyophilisation, refrigerated storage and frozen storage of fresh vegetable extract as a means of standardising coagulant activity in terms of coagulation times, pH and microbiological quality.

RESULTS:Neither the pH nor the coagulation time of lyophilised extracts was significantly modified during 1 year; however, changes were observed following frozen storage, and more notable following refrigerated storage. Lyophilisation of aqueous extracts prompted the destruction of most micro‐organisms; low counts initially noted for total mesophiles, lactic acid bacteria and yeasts disappeared during the first few days of storage, due to low water activity. There was a generalised decrease in micro‐organism counts during frozen storage. Refrigeration was found to be unsuitable for storing of cardoon extract; an increase of roughly 2 log unit counts was recorded in total mesophile, lactic acid bacteria, yeast and mould counts after 1 year of refrigerated storage.

CONCLUSION:Refrigerated storage cannot be considered a suitable method for prolonged conservation of aqueous cardoon extract. Both lyophilisation and frozen storage of aqueous extracts proved ideal for prolonged storage of vegetable coagulant. Lyophilisation additionally had certain advantages over frozen storage. Copyright © 2008 Society of Chemical Industry
Comparison of volatile emissions from undamaged and mechanically damaged almonds
Authors: Beck John J , Higbee Bradley S , Merrill Glory B , Roitman James N
Published: April 2008

BACKGROUND: The navel orangeworm (NOW) Amyelois transitella (Walker) is a major insect pest of almonds causing considerable monetary setbacks for both growers and processors, and thus control of NOW is one of the top priorities for the almond industry. Field observations purport that NOW is attracted to previously injured almonds. Accordingly, in this study the volatile output of damaged almonds was investigated in an effort to identify potential attractants for further studies into the control and/or monitoring of NOW. Mature almonds from the Monterey variety were evaluated for their volatile composition after mechanical damage and compared with the volatile composition of undamaged almonds.

RESULTS: Volatile organic compounds (VOCs) were collected on Tenax, desorbed and identified via gas chromatography/mass spectrometry analysis. VOCs unique to the damaged tree nuts included trace amounts of 3‐pentanol and isomers of the spiroketal chalcogran. VOCs that increased in relative amounts after damage include the spiroketal conophthorin and numerous four‐carbon ester and ketone as well as alcohol derivatives, in addition to two eight‐carbon chain compounds.

CONCLUSION: Several VOCs, both unique and in increased amounts, were identified from damaged almonds. Their presence in damaged almonds warrants further investigation into their role in NOW response to damaged almonds, which may lead to insights into the control and/or monitoring of NOW. Published in 2008 by John Wiley & Sons, Ltd.
The rate of convergence of q‐Durrmeyer operators for 0<q<1
Authors: Gupta Vijay , Heping Wang
Published: April 2008

In the present paper, we introduce certain q‐Durrmeyer operators and estimate the rate of convergence for continuous functions in terms of modulus of continuity. The obtained estimate is sharp with respect to order. Copyright © 2008 John Wiley & Sons, Ltd.
Further Conventions for NMR Shielding and Chemical Shifts (IUPAC Recommendations 2008)
Authors: Harris Robin K. , Becker Edwin D. , De Menezes Sonia M. Cabral , Granger Pierre , Hoffman Roy E. , Zilm Kurt W.
Published: April 2008

IUPAC has published a number of recommendations regarding the reporting of nuclear magnetic resonance (NMR) data, especially chemical shifts. The most recent publication [Pure Appl. Chem. 73, 1795 (2001)] recommended that tetramethylsilane (TMS) serve as a universal reference for reporting the shifts of all nuclides, but it deferred recommendations for several aspects of this subject. This document first examines the extent to which the 1H shielding in TMS itself is subject to change by variation in temperature, concentration, and solvent. On the basis of recently published results, it has been established that the shielding of TMS in solution [along with that of sodium‐3‐(trimethylsilyl)propanesulfonate, DSS, often used as a reference for aqueous solutions] varies only slightly with temperature but is subject to solvent perturbations of a few tenths of a part per million (ppm). Recommendations are given for reporting chemical shifts under most routine experimental conditions and for quantifying effects of temperature and solvent variation, including the use of magnetic susceptibility corrections and of magic‐angle spinning (MAS).

This document provides the first IUPAC recommendations for referencing and reporting chemical shifts in solids, based on high‐resolution MAS studies. Procedures are given for relating 13C NMR chemical shifts in solids to the scales used for high‐resolution studies in the liquid phase. The notation and terminology used for describing chemical shift and shielding tensors in solids are reviewed in some detail, and recommendations are given for best practice. © 2008 IUPAC. Reprinted with permission from Pure Appl. Chem. 2008; 80: 59. This article can be freely downloaded from http://www.iupac.org/publications/pac/80/1/0059/ and can be copied, provided acknowledgement to IUPAC is given.
Organoclays as flame retardants for PVC
Authors: Beyer Günter
Published: April 2008

Peak heat release reduction is lower for plasticized PVC composites containing a modified montmorillonite compared to those formulated with the hectorite. One possible explanation is that the char of the sample containing the modified montmorillonite was less cracked. Both clays initiate accelerated HCl release from PVC resulting in unwanted color changes of the compounds. Copyright © 2008 John Wiley & Sons, Ltd.
Angiotensin‐converting enzyme 2 (ACE2) expression and activity in human carotid atherosclerotic lesions
Authors: Sluimer JC , Gasc JM , Hamming I , van Goor H , Michaud A , van den Akker LH , Jütten B , Cleutjens J , Bijnens APJJ , Corvol P , Daemen MJAP , Heeneman S
Published: April 2008

Angiotensin‐converting enzyme (ACE)2 is a recently identified homologue of ACE. As ACE2 inactivates the pro‐atherogenic angiotensin II, we hypothesize that ACE2 may play a protective role in atherogenesis. The spatiotemporal localization of ACE2 mRNA and protein in human vasculature and a possible association with atherogenesis were investigated using molecular histology (in situ hybridization, immunohistochemistry). Also, the ACE : ACE2 balance was investigated using enzymatic assays. ACE2 mRNA was expressed in early and advanced human carotid atherosclerotic lesions. In addition, ACE2 protein was present in human veins, non‐diseased mammary arteries and atherosclerotic carotid arteries and expressed in endothelial cells, smooth muscle cells and macrophages. Quantitative analysis of immunoreactivity showed that total vessel wall expression of ACE and ACE2 was similar during all stages of atherosclerosis. The observed ACE2 protein was enzymatically active and activity was lower in the stable advanced atherosclerotic lesions, compared to early and ruptured atherosclerotic lesions. These results suggest a differential regulation of ACE2 activity during the progression of atherosclerosis and suggest that this novel molecule of the renin–angiotensin system may play a role in the pathogenesis of atherosclerosis. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Molecular profiling pleomorphic lobular carcinomas of the breast: evidence for a common molecular genetic pathway with classic lobular carcinomas
Authors: Simpson PT , Reis‐Filho JS , Lambros MBK , Jones C , Steele D , Mackay A , Iravani M , Fenwick K , Dexter T , Jones A , Reid L , Da Silva L , Shin SJ , Hardisson D , Ashworth A , Schmitt FC , Palacios J , Lakhani SR
Published: April 2008

Pleomorphic lobular carcinomas (PLC) of the breast display histological features associated with classic invasive lobular carcinoma (ILC), yet they also exhibit more conspicuous nuclear atypia and pleomorphism, and an aggressive clinical behaviour. From a breast cancer progression perspective, it is unclear whether PLC is a variant of ILC or is a high‐grade invasive ductal carcinoma (IDC) that has lost E‐cadherin. The molecular features of 26 PLC were studied using immunohistochemistry [oestrogen receptor (ER), progesterone receptor (PR), HER2, p53 and E‐cadherin], 0.9 Mb resolution, microarray‐based comparative genomic hybridization (aCGH), fluorescent (FISH) and chromogenic (CISH) in situ hybridization and loss of heterozygosity. Comparative analysis was performed with aCGH data from PLC with classic ILC (16 cases) and high grade IDC (35 cases). PLCs were frequently ER‐ and PR‐positive, E‐cadherin‐negative and occasionally HER2‐ and p53‐positive. Recurrent copy number changes identified by aCGH included gains on 1q, 8q, 11q, 12q, 16p and 17q and losses on 8p, 11q, 13q, 16q and Xq. Highly recurrent 1q+ (100% of cases), 16p+ (93%), 11q− (53%) and 16q− (93%) and evidence of the der(1;16)/der(16)t(1;16) rearrangement, as detected by FISH, suggested that PLC had a ‘lobular genotype’. Focal amplifications were evident at 8p12‐p11, 8q24, 11q13.1‐q14.1, 12q14, 17q12 and 20q13. Loss of BRCA2 was detected in 40% of PLC by LOH. Comparative analysis of aCGH data suggested the molecular features of PLC (ER/PR‐positive, E‐cadherin‐negative, 1q+, 11q−, 16p+ and 16q−) were more closely related to those of ILC than IDC, implicating an overlapping developmental pathway for these lobular tumour types. Molecular alterations found in PLC that are more typical of high‐grade IDC than ILC (p53 and HER2 positivity, 8q+, 17q24‐q25+, 13q− and amplification of 8q24, 12q14, 17q12 and 20q13) are likely to drive the high‐grade and more aggressive biology of PLC. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Small is beautiful: microRNAs and breast cancer—where are we now?
Authors: Verghese ET , Hanby AM , Speirs V , Hughes TA
Published: April 2008

MicroRNAs are a recently discovered class of small regulatory RNAs that influence the stability and translational efficiency of target mRNAs. They have been implicated in an increasing number of biological processes, including neoplasia. Recent studies have shown an involvement for these regulatory molecules in breast cancer. For example, miRNA profiling studies have identified microRNAs that are deregulated in breast cancer. Furthermore, functional studies have uncovered their roles in breast cancer as both tumour suppressor genes (eg miR‐335) and oncogenes (eg miR‐21). miRNAs deregulated in breast cancer influence the translational regulation of well‐established regulatory molecules, such as oestrogen receptor‐α, which is regulated by miR‐206, and novel cancer‐related molecules whose functions are not yet fully understood.. Here we present an overview of our current understanding of miRNA in breast cancer. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Tissue engineering of oral dysplasia
Authors: Gaballah K , Costea DE , Hills A , Gollin SM , Harrison P , Partridge M
Published: April 2008

Keratinocytes and fibroblasts isolated from dysplastic oral lesions were combined to provide a renewable source of epithelia. A dysplasia‐scoring index was devised to compare the architectural and cytological features and used together with robust immunophenotyping to show that the engineered epithelia showed most of the characteriztics of the clinical lesions. The strains of dysplastic oral keratinocytes with an extended or immortal lifespan provided a reproducible resource of epithelia showing mild (DOK), moderate (POE9n) or severe (D20) dysplasia when maintained under defined conditions. The dysplasia score was influenced by growth conditions, with KGF polarizing proliferation to the basal layer and reducing the severity of dysplasia. When compared to the normal counterparts, dysplasia‐associated fibroblasts expressed MMP9, secreted more HGF, increased the dysplasia score for epithelia generated with mortal dysplastic keratinocytes and induced morphological changes in normal keratinocytes, highlighting the role of the microenvironment in determining the phenotype of dysplastic epithelia. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Large‐scale N‐terminal deletions but not point mutations stabilize β‐catenin in small bowel carcinomas, suggesting divergent molecular pathways of small and large intestinal carcinogenesis
Authors: Breuhahn K , Singh S , Schirmacher P , Bläker H
Published: April 2008

Small intestinal adenocarcinoma is rare and its molecular pathogenesis is incompletely understood. Stabilization of β‐catenin, a mediator of wnt/wingless signalling, can be detected in 50% of sporadic carcinomas but, in contrast to colorectal cancer, this finding can not be explained by the inactivation of adenomatous polyposis coli (APC). In order to elucidate the molecular background of β‐catenin stabilization in small intestinal adenocarcinoma, we investigated 20 non‐familial adenomatous polyposis coli (FAP)‐associated tumours, including five microsatellite‐unstable carcinomas for β‐catenin alterations, by immunohistochemistry, western blot analysis and sequence analysis on the RNA and DNA levels. Nuclear accumulation of β‐catenin was found in 50% of carcinomas. In 30%, nuclear stabilization was restricted to tumour cells at the invasion front, while 20% of tumours displayed intense homogeneous nuclear stabilization throughout all areas. Large deletions and insertions in the β‐catenin gene (CTNNB1) resulting in a partial or complete in‐frame loss of exons 3 and 4 on the RNA‐transcript level were found in the latter, exclusively microsatellite‐stable carcinomas. The mutations resulted in the stabilization of aberrant β‐catenin lacking large parts of N‐terminal protein domains. No point mutations in CTNNB1 were observed. Our data show that large intragenic CTNNB1 mutations stabilize β‐catenin in small intestinal adenocarcinomas and influence the subcellular distribution of the protein. In contrast to colon carcinomas, neither APC nor CTNNB1 point mutations seem to play a significant role in carcinogenesis, indicating divergent mechanisms of wnt/wingless control in the small and the large intestine. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.