bluuebunny/crossref_metadata_2025 huggingface dataset:
Usage and outcomes of deceased donor liver allografts with preprocurement injury from blunt trauma
Authors: Geenen Irma Laurentia Antonia , Sosef Meindert Nico , Shun Albert , Crawford Michael , Gallagher James , Strasser Simone , Stormon Michael , McCaughan Geoff , Verran Deborah Jean
Published: February 2009

The use of extended criteria donors is an effective way of reducing the shortage of deceased donor organs. Evidence of significant liver trauma in a deceased donor usually rules out transplantation of the liver. The aim of this study was to evaluate the use and outcomes of donor livers with preprocurement trauma. Records of all 312 deceased donors with a history of trauma between January 1986 and September 2007 were reviewed. Donors with macroscopic liver injuries were identified, and data from recipient medical records were obtained. Data on declined donor offers were also evaluated. The median donor age was 20 (range, 10–57) years, and 9 of 15 (60%) were male. The liver injuries were predominantly lacerations (grades 1–5) and vascular injury. The right lobe was resected because of extensive damage in 3 cases. This resulted in 2 left lobes (back-table cut-down) and 1 left lateral segment allograft (in situ split). For the 15 recipients, the median age was 43 (3–69) years. Primary nonfunction was not seen. There was no difference in survival between whole and partial allografts. Three deaths occurred within 3 months post-transplantation. During the same period, 42 of 1405 donor offers (3%) were declined because of extensive liver trauma or major ongoing intra-abdominal hemorrhage. In conclusion, the use of donor livers with preexisting trauma leads to acceptable outcomes. Strategies to deal with trauma include resection of the right lobe if required. Use of deceased donor livers with injury is a safe way to expand the donor pool.
Clinically relevant differences in the model for end-stage liver disease and model for end-stage liver disease–sodium scores determined at three university-based laboratories of the same area
Authors: Xiol Xavier , Gines Pere , Castells Lluis , Twose Jorge , Ribalta Alba , Fuentes-Arderiu Xavier , Rodriguez Santiago , Castellote Jose , Navasa Miquel , Deulofeu Roser
Published: February 2009

The Model for End-Stage Liver Disease (MELD) score is considered an objective and reliable measure of liver disease severity. However, the use of specific laboratory methodologies may introduce significant and clinically relevant variations into the score. It has been suggested that the incorporation of sodium into MELD (MELD-Na) can provide a more accurate survival prediction than MELD alone. Before implementing organ allocation based on the MELD score in an area with 3 transplant centers, we studied whether there were significant variations in MELD and MELD-Na scores determined at each center. Seventy patients on the waiting list were studied simultaneously. Blood samples for each patient were divided into 3 aliquots and were processed in the 3 laboratories in order to calculate MELD and MELD-Na scores. There were statistical differences between the 3 laboratories in the MELD and MELD-Na scores and their parameters. The MELD score was identical in the 3 laboratories for only 6 of the 70 patients, and the MELD-Na score was identical for only 9. MELD and MELD-Na scores from 2 laboratories differed by 1 point or more in 54% and 47% of cases, respectively. Our study confirms that there is major variability in the MELD score, serum sodium, and MELD-Na score. These differences are clinically relevant, and in order to guarantee equitable organ allocation based on the MELD score, similar laboratory methodologies should be implemented at all centers in the same organ procurement area. Alternatively, the possibility of setting up a central laboratory in each organ procurement area should be considered.
Whole‐brain atrophy as a measure of progression in premanifest and early Huntington's disease
Authors: Henley Susie M.D. , Wild Edward J. , Hobbs Nicola Z. , Frost Chris , MacManus David G. , Barker Roger A. , Fox Nick C. , Tabrizi Sarah J.
Published: February 2009

Therapeutic trials in Huntington's disease (HD) are challenging as clinical progression is slow and variable and reliable biomarkers are lacking. We used magnetic resonance imaging and the brain boundary shift integral to quantify whole‐brain atrophy rates over 1 year in early and premanifest HD subjects, and controls. Early HD subjects had statistically significantly (P = 0.007) increased (threefold higher) rates of whole‐brain atrophy compared with controls. Higher atrophy rates were associated with longer CAG repeat length. MRI‐based measures of whole‐brain atrophy may have potential as a measure of progression in HD. © 2009 Movement Disorder Society
Natural gas storage valuation and optimization: A real options application
Authors: Thompson Matt , Davison Matt , Rasmussen Henning
Published: February 2009

In this article, we present an algorithm for the valuation and optimal operation of natural gas storage facilities. Real options theory is used to derive nonlinear partial‐integro‐differential equations (PIDEs), the solution of which give both valuation and optimal operating strategies for these facilities. The equations are designed to incorporate a wide class of spot price models that can exhibit the same time‐dependent, mean‐reverting dynamics, and price spikes as those observed in most energy markets. Particular attention is paid to the operational characteristics of real storage units. These characteristics include working gas capacities, variable deliverability and injection rates, and cycling limitations. We illustrate the model with a numerical example of a salt cavern storage facility that clearly shows how a gas storage facility is like a financial straddle with both put and call properties. Depending on the amount of gas in storage the relative influence of the put and call components vary. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009
Rank‐Cluster‐and‐Prune: An algorithm for generating clusters in complex set partitioning problems
Authors: Cohn Amy , Magazine Michael , Polak George
Published: February 2009

Clustering problems are often difficult to solve due to nonlinear cost functions and complicating constraints. Set partitioning formulations can help overcome these challenges, but at the cost of a very large number of variables. Therefore, techniques such as delayed column generation must be used to solve these large integer programs. The underlying pricing problem can suffer from the same challenges (non‐linear cost, complicating constraints) as the original problem, however, making a mathematical programming approach intractable. Motivated by a real‐world problem in printed circuit board (PCB) manufacturing, we develop a search‐based algorithm (Rank‐Cluster‐and‐Prune) as an alternative, present computational results for the PCB problem to demonstrate the tractability of our approach, and identify a broader class of clustering problems for which this approach can be used. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009
Optimal inventory and dynamic admission policies for a retailer of seasonal products with affiliate programs and drop‐shipping
Authors: Xiao Yongbo , Chen Frank Y. , Chen Jian
Published: February 2009

This article investigates the optimal inventory and admission policies for a “Clicks‐and‐Bricks” retailer of seasonal products that, in addition to selling through its own physical and online stores, also sells through third‐party websites by means of affiliate programs. Through postings on partners' webpages, an affiliate program allows a retailer to attract customers who would otherwise be missed. However, this retailer needs to pay a commission for each sale that originates from the website operators participating in the program. The retailer may also refer online orders to other sources (such as distributors and manufacturers) for fulfillment through a drop‐shipping agreement and thus earns commissions. This would be an option when, for example, the inventories at the physical stores were running low. Therefore, during the selling horizon, the retailer needs to dynamically control the opening/closing of affiliate programs and decide on the fulfillment option for online orders. On the basis of a discrete‐time dynamic programming model, the optimal admission policy of the retailer is investigated in this paper, and the structural properties of the revenue function are characterized. Numerical examples are given to show the revenue impact of optimal admission control. The optimal initial stocking decisions at the physical stores are also studied. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009
Space Mapping Approach for Particle Control in Turbulent Flows
Authors: Marheineke Nicole , Pinnau René , Reséndiz Edgar
Published: February 2009

Controlling the motion of particles in turbulent flows, the paper at hand presents an efficient space–mapping approach that is based on a hierarchy of models. The approach reduces the highly complex optimization of the k‐ε turbulence model for high Reynolds–number flows (fine model) to the cheaper one of the Navier–Stokes equations for smaller Reynolds–number (laminar) flows in direct numerical simulations on coarser grids (coarse model) by help of a space–map function that maps the respective coarse model control onto the desired fine model control. The numerical results are very convincing in terms of accuracy and computational effort. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamics of flow near a separation point
Authors: Uruba V. , Knob M.
Published: February 2009

Dynamical behavior of a boundary layer separation is studied using the experimental approach. The dynamical nature of the phenomenon is demonstrated on a simple case of a flat–plate boundary layer in adverse pressure gradient. The Time–Resolved PIV technique was utilized for monitoring instantaneous structure of the separation region and its time development. Distinctive coherent structures and their dynamical behavior were identified using the Proper Orthogonal Decomposition method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reliability‐Based Optimization of Structural Systems involving Discrete Design Variables
Authors: Valdebenito Marcos A. , Schuëller Gerhart I.
Published: February 2009

This contribution proposes an approach for solving Reliability–based optimization (RBO) problems involving discrete design variables. The proposed approach is based on a decoupling approach and sequential approximations. An application example involving a linear structure under dynamic loading is presented, showing the efficiency of the proposed method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Passivity Criteria for Infinite‐Dimensional Descriptor Systems
Authors: Reis Timo , Jacob Birgit
Published: February 2009

We study infinite–dimensional descriptor systems with the property of input–output–passivity, that is, the Lebesgue inner product of input and output has positive real part. A sufficient criterion for passivity, is given in terms of a certain operator inequality generalizing the Kalman–Yakubovich–Popov inequality. We furthermore characterize passivity in the frequency domain. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Distributional solution theory for linear DAEs
Authors: Trenn Stephan
Published: February 2009

A solution theory for switched linear differential–algebraic equations (DAEs) is developed. To allow for non–smooth coordinate transformation, the coefficients matrices may have distributional entries. Since also distributional solutions are considered it is necessary to define a suitable multiplication for distribution. This is achieved by restricting the space of distributions to the smaller space of piecewise–smooth distributions. Solution formulae for two special DAEs, distributional ordinary differential equations (ODEs) and pure distributional DAEs, are given. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Boundary layer separation from continuous surfaces with increasingly complex topography: a comparative LES, hybrid LES/RANS and RANS study
Authors: Jakirlić Suad , Šarić Sanjin , Kniesner Björn , Kadavelil Gisa , Djugum Adnan , Cavar Dalibor
Published: February 2009

Different wall–bounded flow configurations featured by the boundary layer separation are investigated computationally by using LES (Large–Eddy Simulation), a two–layer, hybrid LES/RANS (HLR) and RANS (Reynolds–Averaged Navier Stokes) methods. The flow cases investigated are featured by a systematic increase in the wall complexity: a backward–facing step flow (ReH=5540; Exp., Kasagi and Matsunaga, 1995), flow in a plane diffuser (Rem=18000; Exp., Obi et al., 1993, Buice and Eaton, 1997), periodic flow over an axisymmetric hill (ReH=10800; LES, Froehlich et al., 2005) and flow over a hump (ReC=936000; Exp., Greenblatt et al., 2004). The main objective of the present work is the in–depth analysis of the flow structure aiming at establishing appropriate criteria for the flow unsteadiness characterization, marking the RANS method capabilities with respect to capturing correctly the mean flow characteristics relative to the LES–related methods. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal control for indoor overhead crane systems with predefined course of crab
Authors: Blume Bodo , Büskens Christof
Published: February 2009

Most papers on optimal control of 3D overhead cranes focus on systems without constraints for the course of the crab (for example [1], [3]). Based on a general 3D model a minimal model with 2 degrees of freedom is developed. Starting from a given initial state the optimal control to reach a given final state is calculated for some predefined courses of the crab. For different turning angles and speeds of the crab an arc of a sine, parabola, circular and an arc of two symmetric clothoid segments have been investigated. Calculations for different values of the mass of the load, turning angles and speed of the crab are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anwendung elastischer Mehrkörpersysteme in der Hochauftriebs‐Entwicklung von Verkehrsflugzeugen
Authors: Heyden Thomas , Woernle Christoph , Winter Evelyn , Zierath János
Published: February 2009

Für Verkehrsflugzeuge erfolgt die Anpassung des Auftriebsbeiwertes für die Start– und Landephase durch so genannte Hochauftriebssysteme. Hochauftriebssysteme bestehen im Allgemeinen aus variablen Flügelgeometrien an der Flügelvorderkante (Vorflügel) und an der Flügelhinterkante (Landeklappen). Die Simulation der Dynamik von Hochauftriebssystemen erfolgt günstig mit der Methode der Mehrkörpersysteme. Mit dieser Methode werden Starrkörperbewegungen (Ein– und Ausfahren der Hochauftriebselemente) exakt erfasst. Elastische Körper werden aus Finite–Elemente Modellen mittels eines modalen Ansatzes in das Mehrkörpersystem integriert. Ein typisches Anwendungsgebiet ist die Berechnung von Reaktionskräften an den Bindungsstellen (Gelenke, Einspannungen) des Systems. Im Rahmen des Beitrags werden der Bruch einer Antriebsstrebe einer Landeklappe und der Einfluss der Flügelverformung auf das Hochauftriebssystem untersucht. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamics of Rigid Spacecraft Under the Influence of Gravity Torques. Theory and Applications.
Authors: Mladenova Clementina
Published: February 2009

This paper considers the dynamic equations of a rigid spacecraft under the influence of the gravity torques written as a first–order form with a constant coefficient matrix which eigenvalues are found analytically. An appropriate parameterization of SO(3) group with nice and clear geometrical properties is used and this turns out to be quite efficient in computational aspects. An example is given, which demonstrates the stability of the model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stable Model Inversion for Underactuated Multibody Systems
Authors: Seifried Robert , Eberhard Peter
Published: February 2009

Inverse models for underactuated multibody systems are presented. The derivation of the inverse model is based on the transformation of the equation of motion into a nonlinear input–output normal–form. These inverse models often include a internal dynamics, for which different methods of solution are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some Methods of Analysis of the Dynamic Systems with the Various Dissipation in Dynamics of a Rigid Body
Authors: Shamolin Maxim V.
Published: February 2009

In is well–known due to its complexity, the problem of the motion of a rigid body in an unbounded medium requires the introduction of certain simplifying restrictions. The main aim in this connection is to introduce hypotheses that would make it possible to study the motion of the rigid body separately from the motion of the medium in which the body is embedded. On the one hand, a similar approach was realized in the classical Kirchhoff problem on the motion of a body in an unbounded ideal incompressible fluid that undergoes an irrotational motion and is at rest at infinity. On the other hand, it is obvious that the above–mentioned Kirchhoff problem does not exhaust the possibilities of this kind of simulation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pathplanning and control of an autonomous robot vehicle with a manipulator
Authors: Stadlbauer Klaus , Bremer Hartmut
Published: February 2009

An autonomous mobile robot is presented. It consists of two parts: a mobile vehicle underneath a robotarm with DOF 5. These two are a nonholomic (the mobile vehicle) and a holonomic subsystem (the robotarm).

To give the robot orders or tasks to accomplish this can be done from an external controlsoftware via TCP–IP to the controlsoftware of the robot. An embedded system involves chart creation, pathplanning (global, local), evaluation of sensorsignals, object– and/or marker–detection and a controlled movement. Futhermore it communicates over FIFOs with an nonrealtime–task which allows a communication via TCP–IP.

Several sensors are implemented, e.g. infrared–/ ultrasonic–range sensors connected via CAN to the embedded board, as well as the control boards for each engine. A Laserscanner is installed in front of the robot to detect edges and obstacles. For marker–tracking and object recognition an USB–Webcam is added on the robotarm.

For avoidance of collisions between the robotarm and the mobile robot a repeller is introduced. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal Control of long cable crane systems
Authors: Vogelsang Jan , Büskens Christof
Published: February 2009

Crane systems like overhead cranes used in high–rack warehouses are usually modeled as a multi body system with the cable modeled as a pendulum whose cable is regarded as linear. With cables around 40–50 meters long, it is possible that the description of the cable by a straight line is not sufficient anymore, because the cable is bended slightly. The shape of the cable is more like a curve than a straight line.

A more suitable description could be achieved by a chain of piecewise linear links, which is again a multi body system and leads to a differential–algebraic system. Each of these links can be modeled again by a pendulum. Using the example of an overhead crane system used in high–rack warehouses, the conventional model with linearly connected trolley and load is compared to the new model with a piecewise linear connection between trolley and load.

The optimal trajectories and controls for both models with respect to the same objective function are analyzed for different cable lengths, loads, transport distances and objective functions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A microstructurally motivated anisotropic viscoelastic model for soft tissues
Authors: Ehret Alexander E. , Itskov Mikhail , Weinhold Georg
Published: February 2009

In this paper, a microstructurally motivated approach to take into account the anisotropic viscoelastic behaviour of soft biological tissues is proposed. The constitutive model is based on the assumption that this behaviour results from an interaction between collagen fibres and surrounding matrix constituents. Accordingly, a non–linear viscoelastic one–dimensional model for fibres and the nearby ground substance is developed. This model is then generalised to the anisotropic three–dimensional case. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical simulation of non‐Newtonian blood flow in bypass models
Authors: Jonášová Alena , Vimmr Jan
Published: February 2009

The article presents the numerical investigation of non–Newtonian effects of steady blood flow in complete idealized 3–D bypass models, whose native artery is either coronary or femoral with average physiological parameters. Considering the blood to be a generalized Newtonian fluid, the shear–dependent viscosity is described by two well–known macroscopic non–Newtonian models (the Carreau–Yasuda model and the modified Cross model). The results were obtained by own developed computational software based on the pseudo–compressibility approach and on the cell–centred finite volume method defined on unstructured hexahedral grids. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability study of the human body‐seat system into an autovehicle
Authors: Simona Rodean , Paul Rodean Claudiu , Geamilia Solea , Arghir Mariana
Published: February 2009

The paper presents the study of the human body, as a mechanical system, seated inside an autovehicle and exposed under the vertical harmonic vibration action during the auto vehicle motion time. The human body may be roughly approximated by a linear lumped parameter at low frequencies and low vibration levels. Therefore, the model has 5 DOFs in translation, where 4 DOFs represents the human body and 1 DOF is for the seat cushion The mechanical model of the human body, in sitting position on the seat cushion of a vehicle seat, consists of four parts: pelvis, upper torso, viscera and head.. The eigenvalues for the human body – seat system and the damping ratio for the system was been calculate. The system stability analysis is given by the existence of a Lyapunov function for the system. The stability of a system can also be characterized by the eigenvalues of the system. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Numerical Simulation of Interlaminar Failure of Composites
Authors: Kula Krzysztof , Schlebusch Rainer , Zastrau Bernd W. , Kuczma Mieczysław
Published: February 2009

This paper deals with one of the most dangerous failure modes in fiber reinforced composites, namely delamination. The laminated structure is modeled by a solid–shell finite element. The mechanical modeling of delamination onset and propagation is based upon a cohesive zone model implemented into a cohesive element located between laminae of a composite structure. The numerical simulations are accomplished within the commercial software package ABAQUS by the implementation of a user–written finite element. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fracture Analysis of Functionally Graded Piezoelectric Materials
Authors: Rao B. N. , Kuna M.
Published: February 2009

This paper presents domain form of interaction integrals based on three independent formulations for computation of stress intensity factors and electric displacement intensity factor for cracks in functionally graded piezoelectric materials. Each of the formulation differs in the way auxiliary fields are imposed in the evaluation of interaction integral and each of them results in a consistent form of interaction integral in the sense that extra terms naturally appears in their derivation to compensate for the difference in the chosen crack tip asymptotic fields of homogeneous and functionally graded piezoelectric medium. The additional terms play an important role of ensuring domain independence of the presented interaction integrals. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Material force method: theoretical and numerical aspects in nonlinear electro‐elastostatics
Authors: Vu Duc Khoi , Steinmann Paul
Published: February 2009

Formulations of the spatial and material motion problem in nonlinear electroelastostatics are considered in this work by a virtual work approach. Based on these formulations, a finite element discretization is realized and a numerical example is presented to demonstrate possible uses of the material force method in studying the closing process of cracks. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of Rosenbrock‐type methods to a finite element formulation based on large strain viscoelasticity
Authors: Hamkar Ahmad‐Wahadj , Hartmann Stefan
Published: February 2009

The present paper is focused on the solution of differential–algebraic equation systems (DAE), which arise in large viscoelastic deformations within the quasi–static finite element context. For this purpose linearly implicit methods of Rosenbrock–type are used, which avoid completely the solution of non–linear equations. This article investigates a possible treatment of the new global approach with respect to expense and achievable accuracy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A finite element framework for the numerical implementation of boundary potentials
Authors: Javili Ali , Steinmann Paul
Published: February 2009

This contribution deals with the implications of boundary potential energies on deformational mechanics in the framework of the finite element method at finite strains. The common material models in continuum mechanics are taking the bulk into account, nevertheless, neglecting the boundary. However, boundary effects sometimes play a dominant role in the material behavior, e.g. surface tension in fluids. The boundary potentials, in general, are allowed to depend not only on the boundary deformation gradient but also on the spatial surface–normal / curve–tangent, as well. For the finite element implementation, a suitable curvilinear coordinate system attached to the boundary is defined and corresponding geometrical and kinematical derivations are carried out. Afterwards, the discretization of the generalized weak formulation, including boundary potentials, is carried out and finally numerical examples are presented to demonstrate the boundary effects due to the different proposed material behavior. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Goal‐oriented r‐adaptivity based on the evaluation of the physical and material residual
Authors: Materna Daniel , Barthold Franz‐Joseph
Published: February 2009

This contribution is concerned with goal–oriented r‐adaptivity based on energy minimization principles for the primal and the dual problem. We obtain a material residual of the primal and of the dual problem, which are indicators for non–optimal finite element meshes. For goal–oriented r‐adaptivity we have to optimize the mesh with respect to the dual solution, because the error of a local quantity of interest depends on the error in the corresponding dual solution. We use the material residual of the primal and dual problem in order to obtain a procedure for mesh optimization with respect to a local quantity of interest. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aspects Regarding the Conception, Modeling and Implementation of an Articulated Robot in Space with Noises and Vibrations
Authors: Ispas Virgil , Petrişor Silviu Mihai , Arghir Mariana , Ispas Viorel
Published: February 2009

The authors want to conceive and to model a structure of a 6R serial modular industrial robot with six freedom degrees. Some specific points are followed: the direct geometric modelling of the robot using the matrix of rotation method, the given in 3D modelling of the robot, the presentation of its components having some possible applications in the processes of production in the spaces with noises and vibrations. The direct geometrical modelling will be determinate the relative orientation matrices, which express the position of each system Ti, (i=1‐6), according to the system Ti–1, also expressing the vectors of relative position of origin Oi of the systems Ti. They will be expressed the orientation of each system Ti in account to the fixed system To attached to the robot base, the set of independent parameters of orientation then are obtained the final equation of the column vector of the generalized coordinates, which express the position and the orientation of the clamping device. The paper presents the two possible applications of the studied robot implementation in a flexible manufacturing cel for the manipulation operations of parts. The robot will be used on the other side for the execution of weld in a points applied to the car carcases. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The relationship of the level of circulating antiangiogenic factors to the clinical manifestations of preeclampsia
Authors: Kim Young Nam , Lee Dae Shim , Jeong Dae Hoon , Sung Moon Su , Kim Ki Tae
Published: February 2009

Objective

This study investigated whether the antiangiogenic factors' concentrations differ according to the clinical manifestations of preeclampsia.

Methods

This study included 62 preeclampsia and compared the soluble fms‐like tyrosine kinase‐1 (sFlt‐1), soluble endoglin (sEng), and placental growth factor (PlGF) concentrations among patients with different clinical manifestations of preeclampsia. We also compared the patients with preeclampsia to 62 controls matched by age, gestational age, and parity after 20 weeks of gestation.

Results

The sEng concentrations were significantly elevated in early‐onset than in late‐onset preeclampsia (105.4 ± 37.9 vs 66.3 ± 36.0 ng/mL, p = 0.0008). Moreover, the sEng levels were also higher in severe preeclampsia compared to mild (42.5 ± 31.0 vs 79.2 ± 38.6 ng/mL, p = 0.0013) and in the small for gestational age (SGA) group compared to the group without SGA (68.3 ± 39.3 vs 85.7 ± 38.2 ng/mL, p = 0.0273). The sFlt‐1 levels, however, did not reveal significant difference according to the onset‐time, severity, and presence of SGA. The antiangiogenic factors' concentrations were not related with the degree of hypertension or proteinuria.

Conclusion

Altered antiangiogenic factors might be involved in the pathogenesis of preeclampsia with synergistic, but different roles. Especially, sEng may be more related with early and severe preeclampsia. Copyright © 2009 John Wiley & Sons, Ltd.
Study of fluorescent nanoparticle comprising iron DMAc complex embedded within polyimide matrix
Authors: Kundnani Chitra , Gupta Anand Kumar , Arya Madhulica , Shrivastava Deepali , Aseri Priyanka , Keller Jagmohan , Bajpai Rakesh
Published: February 2009

Iron complexed with dimethylacetamide (DMAc) was incorporated in variable ultra low concentration in polyimide (PI) at it precursor stage to obtain nanoscopically manipulated metallopolyimide films. The in situ generation of these nanophase structures, their stability within PI matrix, and interaction with its chains was studied using UV–vis spectroscopy. AFM topographic image shows the presence of rock‐shaped nano particles, which is produced by the formation of polyamic acid salt of Fe‐DMAc complex. Unique fluorescence and improved hydrolytic stability of these metallopolyimide films were due to the formation of nanophase structures. Different photo‐physical properties of developed films are attributed to size quantization effect. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Gamma‐irradiation effects on polypropylene‐based composites with and without an internal lubricant
Authors: Brostow Witold , Deshpande Sameer , Fan Kimberly , Mahendrakar Sridhar , Pietkiewicz Dorota , Wisner Steve R.
Published: February 2009

Polypropylene (PP) based materials for nonreusable syringe applications have been investigated, some of them containing an internal liquid lubricant. Hardness, tensile properties, and friction measured by two distinct procedures have been determined. We report three series of results: for nonirradiated samples; for samples directly after stopping the irradiation; and also for samples after accelerated aging equivalent to 2 years of shelf life. We find that effects of irradiation and aging on Shore A and Shore D hardness are small. Tensile strength at break, elongation at yield, and elongation at break all decrease after irradiation and then decrease still more after aging; these results are quantified but expected. By contrast, results from pin‐on‐disk tribometry are quite varied. In some cases γ irradiation and aging both increase friction, in other cases both decrease friction. We also have a case when irradiation increases friction while aging decreases it—as well as vice versa. Possible mechanisms of all these types of behavior are advanced. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Fracture analysis of rubber‐like materials using global and local approaches: Initiation and propagation direction of a crack
Authors: Aït Hocine N. , Naït Abdelaziz M.
Published: February 2009

In this work, fracture of elastomers is analyzed using global and local approaches, combining experiments, analytical developments, and finite element calculations. The J‐integral is chosen as a global parameter characterizing crack initiation in such materials. Particular attention is paid to single specimen methods for measuring the fracture surface energy. More precisely, models developed in the literature are summarized and, because of the lack of accuracy of these models, an original pertinent expression of J is proposed by analogy with linear elastic fracture mechanics frameworks. However, the J‐integral is not able to predict the kinetic or the propagation direction of a crack. Thus, some local parameters are examined: principal strains, principal stresses, and the strain energy density (SED) factor. Results revealed that all these parameters represent reasonable indicators of the crack propagation direction in elastomers. Moreover, unlike maximal principal stress and SED factor, maximal principal strain seems to govern the crack initiation in this kind of materials. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Viscoelasticity and mechanical properties of reactive PVC plastisols
Authors: Boudhani Hassane , Lainé Carole , Fulchiron René , Bounor‐Legaré Véronique , Cassagnau Philippe
Published: February 2009

Reactive poly(vinyl chloride) (PVC) plastisols have been developed to substitute the hydrocarbon diluents generally used in low viscosity PVC plastisols. For this purpose, methacrylate monomers (5–15%) were added in the PVC suspension (based on diisononyl phtalate plasticizer) to reduce the viscosity at room temperature and to polymerize (by radical polymerization initiated by an organic peroxide) during the gelation process. Both the reactive processing and the gelation process were carried out between the plates of a rheometer cell in the linear viscoelasticity domain (small deformation) and under increasing temperature from room temperature up to 160°C (ω = 6.283 rad s−1,
$ \dot {\rm T} $
= 5°C min−1). A temperature criterion was proposed to define the right balance between the polymerization and the gelation to get the best mechanical properties (i.e., elongation and stress at break). The polymerization process must be slower than the gelation process as the polymerization must take place when PVC grains have fused together to form a homogeneous medium at least at the microscale. Actually, the polymerization kinetics can be controlled by the decomposition kinetics of the organic peroxide. Finally, triethylene glycol dimethacrylate and lauryl methacrylate monomers and dicumyl peroxide as initiator turned out to be the best reactive system for some potential industrial applications. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Understanding the Adoption of Project Management in Serbian Organizations: Insights from an Exploratory Study
Authors: Cicmil Svetlana , Dordević Zoran , Zivanovic Sasa
Published: February 2009

The article contributes to our understanding of the drivers behind, and the nature of, project management implementation in the complex context of a transitional economy. Relevant insights are generated through an integrated and dynamic analysis of interviews and secondary data from a sample of local organizations, based on a conceptual model of strategic transformation. The analysis concludes with propositions about how both adoption of and resistance to project management implementation in the region could be understood from a strategic point of view, taking into account complex and dissonant circumstances of transition, history, cultural tradition, embedded social values, and identities of individual organizational members.
The Value of Project Management to Organizations in Canada and Germany, or Do Values Add Value? Five Case Studies
Authors: Mengel Thomas , Cowan-Sahadath Kathy , Follert Friedbert
Published: February 2009

Five case studies have been conducted: four in Canada and one in Germany. The authors of this article were particularly interested in understanding the value of values and meaning in the context of project management implementation and project environments. The article first summarizes the authors’ particular approach. It then discusses the five case studies and their findings. These findings will be grouped around the concepts of value of project management and meaningful work. In conclusion, the findings of this study will be summarized across all five case studies and based on a comparative content analysis.
Understanding the Value of Project Management from a Stakeholder's Perspective: Case Study of Mega-Project Management
Authors: Zhai Li , Xin Yanfei , Cheng Chaosheng
Published: February 2009

Project management can generate significant value for organizations (Thomas & Mullaly, 2007). However, the value of project management varies depending on the different size and complexity of projects managed. Focusing on mega-projects, this study explores the value of project management from the stakeholders’ perspective, thereby creating a value framework. In the case of SHRBC Company, it analyzes the company's project management practice and the value of project management, and consequently certifies the applicability of this value framework through empirical study.
Project Management Systems: Moving Project Management from an Operational to a Strategic Discipline
Authors: Cooke-Davies Terence J. , Crawford Lynn H. , Lechler Thomas G.
Published: February 2009

This article illustrates one aspect of the concept of “fit” between an organization's implementation of project management and its organizational context by exploring how the underlying drivers of an organization's strategy might influence not only the nature of the projects that it undertakes, but also the appropriateness of the arrangements that it makes to manage those projects. Using a model conceptualized from the literature on strategic management, an analysis of four organizations that have made significant investments in project management over the past 5 years supports the hypothesis that the degree of “fit” between an organization's strategic drivers of value and the configuration of its project management system influences the value it obtains from project management.
Rural breast cancer survivors: exercise preferences and their determinants
Authors: Rogers Laura Q. , Markwell Stephen J. , Verhulst Steven , McAuley Edward , Courneya Kerry S.
Published: February 2009

Objective: As a first step in planning interventions to promote exercise in rural breast cancer survivors (BCS), we sought to determine the exercise preferences of rural BCS and to identify the major determinants of these preferences.

Methods: Self‐administered mail survey to a population‐based sample from a state cancer registry.

Results: Among the 483 respondents, 96% were White with mean education of 13±2.5 years and mean months since diagnosis of 39.0±21.5. Only 19% reported ⩾150 min of moderate to vigorous physical activity per week. Although up to half were open to various counseling options, the most popular options were counseling after treatment (36%), face‐to‐face (47%), and from an exercise specialist (40%). Rural BCS preferred home‐based (63%), unsupervised (47%), moderate intensity exercise (65%) that was primarily walking. The strongest preference correlates include higher education with exercise specialist, higher environment score with outdoors, more comorbidities with low intensity and counseling after cancer treatment, higher social support with exercising with friends or family, sedentary or insufficient physical activity with low intensity, and lower household income with preferring supervised exercise.

Conclusions: Interventions designed to promote exercise among rural BCS are needed. Such interventions should consider the environmental aspects of this population and include multiple options based on the preferences of targeted subgroups. Copyright © 2009 John Wiley & Sons, Ltd.
Correlates of physical activity among lung cancer survivors
Authors: Coups Elliot J. , Park Bernard J. , Feinstein Marc B. , Steingart Richard M. , Egleston Brian L. , Wilson Donna J. , Ostroff Jamie S.
Published: February 2009

Objective: Lung cancer survivors commonly experience impairments in quality of life, which may be improved through regular physical activity. However, little is known regarding correlates of physical activity in this survivor population. The current study addressed this research gap.

Methods: The participants were 175 survivors of early‐stage non‐small cell lung cancer who completed surgical treatment from 1 to 6 years previously. Information regarding medical factors was obtained from chart records and from participant self‐report. Participants also answered questions about demographic and social cognitive factors that may be associated with physical activity, which was assessed as reported engagement in moderate/strenuous activities and leisurely walking.

Results: Participants reported an average of 77.7 min of moderate/strenuous weekly activity and 64.6% reported engaging in leisurely walking at least three times per week. Less leisurely walking was reported by older individuals (p=0.001) and those with a lower education level (p<0.001), who also reported less engagement in moderate/strenuous activities (p=0.004). Individuals with poorer pre‐operative pulmonary function reported less moderate/strenuous physical activity (p=0.014) and the number of surgical complications was inversely associated with leisurely walking (p=0.003). Multiple social cognitive constructs were associated with moderate/strenuous activity and leisurely walking.

Conclusions: The study identified several lung cancer survivor subgroups who may be most in need of physical activity interventions. Identification of social cognitive correlates of physical activity provides valuable information regarding theory‐guided constructs that should be targeted in future physical activity interventions for lung cancer survivors. Copyright © 2009 John Wiley & Sons, Ltd.
Optical properties of AgInS2 thin films prepared by sulfurization of evaporated metal precursors
Authors: Nakamura Shigeyuki , Seto Satoru
Published: February 2009

Photoluminescence study has been demonstrated for AgInS2 thin films prepared by sulfurization of metal‐evaporated precursors as well as XRD measurement. We have found the 1.79 eV DAP recombination emission for the stoichiometric thin film containing both chalcopyrite and orthorhombic form. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Epitaxial growth of chalcopyrite CuInS2 films on GaP(001) by controlling [Cu]/[In] ratio
Authors: Vequizo Reynaldo Magdadaro , Tsuboi Nozomu , Kobayashi Satoshi , Oishi Koichiro , Kaneko Futao
Published: February 2009

Epitaxial growth of CuInS2 films with various [Cu]/[In] ratios at 570 °C on GaP (001) substrates is presented with structural and luminescent investigations. CuIn5S8 phase with Cu‐Au ordered CuInS2 dominate in almost stoichiometric films while Cu‐Au ordering of CuInS2 was observed in Cu‐rich films. Chalcopyrite ordering of CuInS2 was highly evident in the slightly Cu‐rich films at a narrow range of 1.28 ≤ [Cu]/[In] ≤ 1.41. These slightly Cu‐rich films exhibited streaky reflection high energy electron diffraction patterns corresponding to the c‐axis oriented chalcopyrite structure without the other oriented structures were observed, indicating highly structural quality of CuInS2 epitaxial films. Broad emission bands in the band‐edge region were observed in the films. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence and time‐resolved photoluminescence in Cu(In,Ga)Se2 thin films and solar cells
Authors: Shirakata Sho , Nakada Tokio
Published: February 2009

Photoluminescence (PL) and time‐resolved PL (TR‐PL) studies have been carried out on Cu(In,Ga)Se2 (CIGS) thin films and solar cells (ZnO/CdS/CIGS) to study the recombination of the photo‐excited carriers. The CIGS solar cells exhibited intense near‐band‐edge (NBE) PL compared with the CIGS films by two orders of magnitude. PL decay time of the cell is strongly dependent on the repetition frequency of the excitation light. PL decay time of the cell is longer than that of the corresponding CIGS thin film. The chemical bath deposition of the CdS buffer layer on CIGS leads to changes in PL intensity, defect‐related PL and the PL decay time. They are discussed with relation to the substitution of Cd atom at the Cu site at the Cu‐deficient surface of CIGS thin film. Under the open circuit condition, NBE‐PL is stronger and the decay time is longer compared with those under the short circuit condition. PL of the cell under the load was examined, and PL intensity and PL decay time are related to the photovoltage during PL measurements. Low temperature PL suggests that the Cd diffusion during the CBD process is pronounced for low Ga content CIGS. The authors demonstrate the effectiveness of PL as a powerful non‐destructive device and photovoltaic characterization methods of CIGS solar cells. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence properties of ZnSnP2 single crystals
Authors: Miyauchi Keisuke , Minemura Takehiro , Nakatani Keigo , Nakanishi Hisayuki , Sugiyama Mutsumi , Shirakata Sho
Published: February 2009

Photoluminescence (PL) spectra of bulk ZnSnP2 crystals grown by solution growth (SG) and normal freezing (NF) methods are described. The donor‐acceptor pair (DAP) transition, which possibly originates from the transition from Sn levels at Zn sites (SnZn) to Zn vacancy (VZn) levels, is observed in the crystals grown by the SG method. The PL spectra of the crystals grown by the NF method exhibit free‐to‐bound transitions. Ionization energies of the SnZn and VZn levels are estimated to be approximately 110 and 40–50 meV, respectively. These results are the first step toward realizing novel functions of optical devices using ZnSnP2. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time‐dependent evolution of crystal lattice, defects and impurities in CdIn2S4 and GaP
Authors: Pyshkin Sergei L. , Ballato John , Bass Michael , Chumanov George , Turri Giorgio
Published: February 2009

We demonstrate that in III‐V and ternary compounds the natural stimuli for ordered distribution of impurities along crystal nodes and interstitials, host atoms and inherent vacancies in right lattice positions prevail over the others which could lead to a heterogenic distribution. The result is obtained in the crystals, prepared in 1963‐1977, due to each 10‐15 years monitoring of their optical and mechanical properties. Here we have summarized the results of the 2005‐2008 monitoring and compare them with the earlier obtained data. We show that the partly inverse spinel CdIn2S4 turns into the perfect normal spinel, while in GaP the impurity ordering leads to the formation of a new type of crystal lattices. Periodically disposed impurities and inherent structural defects modify, improve and stabilize properties of the crystals. New luminescent phenomena of these crystals, including stimulated emission and “hot” luminescence have been discovered. The existing technologies help us to reproduce these naturally ordered structures and to apply them for new generation of optoelectronic devices. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)