bluuebunny/crossref_metadata_2025 huggingface dataset:
E-Impresa
Authors: Sedehi Habib
Published: May 2010

Electronic commerce, marketing on line, and network economy are today’s keywords of (possible) success. But how many managers effectively know about the cost and benefits of starting to sell their products and services through the Web? How much they should invest at the beginning and how long does it takes to have a break-even point of their investment? In order to give support for better understanding the process of the Web marketing and to have more elements to decide to “dive” or not in this virtual world a System Dynamics (SD) model (Forrester J.W. 1961, 1971, 1980), has been developed. The model has the aim to support strategic decisions for SME involvement in e-Commerce, pointed out to guarantee sustainable growth and medium-long term success. The project e-Impresa1 analyses the whole process of the investment in building and maintaining a web site, taking into account the main variables of E-commerce. Through a case study, a SD business game model has been developed. The model gives the opportunity to users to evaluate different what-if analysis through the simulation period time (2 years) at each model step time (4 weeks). This chapter will explain the overall architecture of the model and will present some results of use of the model in different conditions.
Preparedness of Small and Medium-Sized Enterprises to Use Information and Communication Technology as a Strategic Tool
Authors: Antlova Klara
Published: May 2010

The objective of this chapter is to emphasize issues connected with adoption of information and communication technology (ICT) as a strategic tool contributing to further organizational growth. This understanding is based on the results of a qualitative analysis of a group of small and medium-sized enterprises (SMEs). Gradual development of a group of 30 organizations has been monitored over the last fifteen years during their co-operation with the Technical University of Liberec. These organizations have hosted one-year student placements where students, as part of their Bachelor’s degree course, undertake a long term work experience enabling them to integrate the practical and theoretical aspects of their course. The research focused on SME management’s approach to ICT, its utilization for competitive advantage and its relation to and defining of business strategy. Other aspects of the study looked at the effect of ICT on organizational performance, knowledge and skills of the employees, training and organizational culture. The results indicate that successful and growing companies have gradually established business, information and knowledge strategies and make strategic use of ICT.
Elements that Can Explain the Degree of Success of ERP Systems Implementation
Authors: de Pablos Heredero Carmen , de Pablos Heredero Mónica
Published: May 2010

The implementation of an Enterprise Resource Planning System (ERP) is a risky and high cost action, even more when we are dealing with small and medium sized enterprises. Although many studies have shown the importance of paying attention to critical success factors in ERP implementations, there is still a high degree of failures and bad experiences around ERP implementations. Most literature has shown experiences of success and failure coming from large sized firms. But there is a lack of information of what has happened in the area of small and medium size firms, and for some economies, they are essential. In this chapter, we try to show a model containing the main elements that can better explain the degree of success and of failure in ERP implementations by providing examples mainly affecting to the circumstances of small and medium size firms. In our model, we propose 5 main groups of variables affecting final results in ERP implementations.
Change Management Strategies for ERP Implementation in SME and a Case Study in Turkey
Authors: Vayvay Özalp , Derman Ilhan , Beceren Ergin
Published: May 2010

SMEs differ from large firms in terms of environmental uncertainty, dependency, centralization, specialization, strategy, systems, resources and flexibility. Because of these distinguishing characteristics, the results of research carried out in large firms cannot be transferred directly to small firms. This is particularly true of the critical success factors for change management and technology implementation. Generally, SMEs tend to adopt new technologies after large firms. The case study in Turkey, represents the change management activities on ERP implementation by a consultancy firm (ABH) on an international corporation’s Turkey located SME.
Leading in a Knowledge Era
Authors: Jayasingham Sharmila , Ansari Mahfooz A.
Published: May 2010

Knowledge management (KM) has been found to be a critical success factor for organizational performance. However, most organizations are found to be purely focused on the technological perspectives of KM initiatives at the expense of people perspective. They fail to realize that the success of any KM system relies upon the acceptance and motivation of knowledge worker (k-worker), the primary player in any KM initiatives. Here, knowledge leaders have a crucial role to play in influencing and encouraging k-workers to adopt KM practices. However, a transformation of leader behavior is required to manage this new generation of workers. This chapter thus highlights the power-influence approach to leadership behavior in promoting and instilling KM practices among k-workers.
Managing in the Time of Virtualness
Authors: Carte Traci , King Heather
Published: May 2010

Virtual teams are increasingly being utilized by organizations in order to bring together far-flung expertise using collaborative technologies rather than physical relocation. While many organizations have been quick to utilize technology to enable this new virtual team structure they have been slower in recognizing the needed complementary shifts in management practices surrounding such teams. This chapter seeks to offer advice to managers in this new time of “virtualness.” Interviews were conducted with a variety of individuals engaged in virtual team activities asking about communication practices, performance, change management, and leadership. The authors further probed about what technologies were in use by teams and what areas of the team processes could be improved. Finally, they asked the participants to draw distinctions between their views on effective practices of face-to-face teams and effective practices of virtual teams. From this interview data, insights are offered into social and managerial issues that drive virtual team performance.
Knowledge Brokers in Overlapping Online Communities of Practice
Authors: Cranefield Jocelyn , Yoong Pak
Published: May 2010

This chapter argues that leaders need to better understand the roles played by informal knowledge brokers in connecting overlapping online communities of practice (CoPs). It illustrates how distributed individuals playing a key knowledge broker role – the Connector-leader – helped to drive transformative professional change. The research context was a professional development programme for New Zealand schools that promoted a new, student-centric teaching approach. The research project explored how online CoPs facilitate professional knowledge transfer, focusing on how new knowledge is embedded in interpretive frameworks and practices. Connector-leaders spanned boundaries in the online community realm and had a strong online presence. As professional learners, they were strongly outward facing, identifying primarily as members of a distributed online CoP. As leaders, they were inward facing, focusing largely on the knowledge needs of local organisations and CoPs. This study extends previous research into the boundary spanner and knowledge broker, introduces new ideas about the nature of boundaries in CoPs, and promotes a system-level view of knowledge flows, emphasising the importance of both visible and invisible dimensions of online knowledge brokering.
Exploring Leadership in E-Commerce Adoption in Australian SMEs
Authors: Scupola Ada
Published: May 2010

This chapter presents the results of a study investigating leadership and leadership styles in e-commerce adoption in small and medium size enterprises in Australia. The results show that top management and CEO’ leadership have a key role in small and medium size enterprises (SMEs) in developing a vision for e-commerce adoption and that the dominant leadership style is directive with some signs of consultative. Furthermore the study shows that e-commerce adoption is becoming a strategic process and in this process top management is taking into consideration both the organizational knowledge and the knowledge of external consultants.
Assessment Strategies for Servant Leadership Practice in the Virtual Organization
Authors: Molnar Darin R.
Published: May 2010

Leadership in the virtual organization presents unique opportunities and challenges for the manager. Some researchers consider management in the virtual organization to be comprised mainly of challenges while others see it as the opportunity to realize competitive advantage in the global marketplace. Several leadership approaches offer interesting options for the manager within the context of the virtual organization. One standout approach that has gained increasing popularity over the last 30 years is servant leadership in which the leader is servant first. Those managers in virtual organizations who have committed to a practice of servant leadership recognize the need for assessment instruments to help them understand the level of perceived servant leadership characteristics among organizational members under their guidance. This understanding acts as a foundation for training within this context. With this in mind, Laub’s Organizational Leadership Assessment (OLA) offers a reliable survey instrument accepted by the servant leadership practice community. The OLA is easily administered to virtual organization members as a set of Web pages and can be used in conjunction with complementary, third-party data sets such as the World Values Survey database. Future directions for the assessment of servant leadership in the virtual organization include the potential modification of the OLA, as well as the creation of survey instruments to be used in conjunction with it.
A Question for Research
Authors: Stowell Frank
Published: May 2010

In this chapter I raise questions about the nature of Information systems, the way that they are designed and developed and suggest areas that IS researchers may wish to investigate. A concern is raised about the way we think about the domain of information systems and a suggestion made that rather than think of it in terms of the mnemonic IS, with is association with IT, it should be thought of in terms of as systems of information. This suggestion is made as a means of highlighting considerations developers have to take into account which go beyond those of technology alone. As a means of instigating this proposition four questions are raised in the chapter which are intended to stimulate further information systems research. These questions are about the nature of IS, design Methods, the underpinning philosophy and finally, IS failure.
Importance of Systems Engineering in the Development of Information Systems
Authors: Kljajic Miroljub , Farr John V.
Published: May 2010

The interrelationship between Information Systems (IS), Systems Engineering (SE), and Information Systems Development (ISD) is discussed from past, present, and future perspectives. While SE is relatively a well-established discipline based upon an interdisciplinary approach to enable the realization of successful systems, ISD has evolved to a variant of SE applied mainly for the development of IS. Given the growth in complexity, need for enterprise wide solutions, and the cost and schedule overruns that have be common place for modern software centric systems, well-established tools, techniques, and processes are needed for the development of good IS. Similarities and differences of methodology as well as their evolution and perspectives are also presented herein. We found a positive trend in the evolution of research methodology and published material in SE and its use in IS.
An Analysis of the Imbursement of Currency in a Debt-Based Money-Information System
Authors: Swanson G. A.
Published: May 2010

The imbursement of currency into modern debtbased money-information systems is a concrete phenomenon. Economic jargon traffics in abstract concepts. This analysis attempts to bridge the gap between the abstract and the concrete and to provide practical insights into certain social consequences of different modes of currency imbursement. Information science, like economics, has developed as an analytic science. Many reasons might explain that development. Not least among them is the daunting complexity of the matter-energy systems they concern. Button and Dourish (1996) provide an interesting view of the role of systems design to provide an opaque barrier for decisionmakers against that complexity while enabling engagement. That conceptual distance can give a false sense that the design of information systems should be limited only by imagination. Many definitions of information have been proposed and some have gained acceptance in certain circles. In some highly abstracted systems, Bateson’s (1972, xxv-xxvi) “difference that makes a difference” has appeal. Nevertheless, when we consider that technology emerges in self-organizing, evolving living systems that exist in physical space-time, that definition has little explanatory power. Alternatively, Shannon’s H restatement of the measure of entropy (Shannon, 1948) that became known as a measure of information is significantly explicatory of an essential connection between information and matter-energy processes. Shannon’s treatment of information as a reduction of uncertainty has found wide application.
Case Study - "Can You See Me?"
Authors: DiPardo Anne , DiPardo Mike
Published: May 2010

This chapter presents a case study detailing how geographically dispersed software developers employ writing in the process of creating and troubleshooting products for use in the healthcare industry. It focuses particularly on their efforts to arrive at language that unambiguously reflects functional requirements and optimal design principles. After a brief history of the company and the evolution of its national and international virtual collaboration practices, the authors turn to the role of text across particular task cycles, exploring the uses of writing in generating, designing, and refining plans and products. Focusing on a series of three composing sequences, the authors highlight the incremental process by which the team moves toward a shared sense of understanding and linguistic precision. They argue that in contrast to common conceptions of texts as simple containers for preformed ideas, these episodes provide a more nuanced picture, as writing comes to play a central role in constituting and fine-tuning meaning and in maintaining strong working relationships throughout the processes of developing and refining products. They close with implications for preparing diverse virtual teams for participation in tasks that demand exacting uses of the written word.
Case Study
Authors: Brunk-Chavez Beth , Palsole Sunay
Published: May 2010

This chapter features a case study of a collaborative project among a team of writers and a team of multimedia designers and examines their intersections. The chapter’s central question is: What does it take to enable collective collaboration in a virtual writing environment? The chapter is based in part on a study that found that building and strengthening social presence is integral to effective collaboration. The spoken and unspoken social contracts of working toward a common goal in a respectful environment are important. It also found that the technologies must be adoptable, adaptable, and they must enable anywhere/anytime collaboration. Therefore, collaboration using technologies is a complex process involving social presence, availability, and adaption/adoption of technologies with the changing needs of the collaborative team.
CO2, δO2/N2 and APO: observations from the Lutjewad, Mace Head and F3 platform flask sampling network
Authors: van der Laan-Luijkx I. T. , Karstens U. , Steinbach J. , Gerbig C. , Sirignano C. , Neubert R. E. M. , van der Laan S. , Meijer H. A. J.
Published: May 2010

Abstract. We report results from our atmospheric flask sampling network for three European sites: Lutjewad in the Netherlands, Mace Head in Ireland and the North Sea F3 platform. The air samples from these stations are primarily being analyzed for their CO2 and O2 concentrations. In this paper we present the CO2 and O2 data series from these sites between 1998 and 2009, as well as the atmospheric potential oxygen (APO). The seasonal pattern and long term trends agree to a large extent between our three measurement locations. We however find an increasing gradient between Mace Head and Lutjewad, both for CO2 and O2. As Lutjewad is influenced by local fluctuations in the fossil fuel sources, we use an atmospheric transport model in combination with CO2 emission data and information on the fossil fuel mix per region and category in order to correct the tracer APO for a residual fossil fuel component. For Lutjewad this correction differs significantly from the global average. Using the APO trend from Mace Head we obtain an estimate for the global oceanic CO2 uptake of 1.8 ± 0.8 PgC/year.
Clear-sky direct aerosol radiative forcing variations over mega-city Delhi
Authors: Singh S. , Soni K. , Bano T. , Tanwar R. S. , Nath S. , Arya B. C.
Published: May 2010

Abstract. The direct aerosol radiative forcing (DARF) has been estimated for the clear-sky conditions over Delhi from January 2006 to January 2007 using Santa Barbara DISORT Atmospheric Radiative Transfer model (SBDART) in the wavelength range 300–3000 nanometer. The single scattering albedo (SSA) and the asymmetry parameter used in this model were estimated using the Optical Properties of Aerosol and Cloud (OPAC) model. The annual average AOD observed at 500 nm was ~0.86±0.42 with an average Angstrom exponent ~0.68±0.35. The average monthly AOD throughout the year over Delhi was found to be in the range 0.56 to 1.22 with the Angstrom exponent in the range 0.38 to 0.96. A high monthly average BC concentration in the range 4–15 μg m−3 led to monthly average SSA in the range 0.90±0.4 to 0.74±0.3 during the year. Consequently, the monthly average clear-sky DARF at the surface was found to vary in the range −46±8 W m−2 to −110±20 W m−2, at TOA in the range −1.4±0.4 to 21±2 W m−2, whereas in the atmosphere it was in the range 46±9 W m−2 to 115±19 W m−2 throughout the year. As the dust concentration in the atmosphere was highest (May–June) the SSA showed an increase with wavelength however when dust concentration was low the SSA decreased with the wavelength.
Observed and modelled ecosystem respiration and gross primary production of a grassland in southwestern France
Authors: Albergel C. , Calvet J.-C. , Gibelin A.-L. , Lafont S. , Roujean J.-L. , Berne C. , Traullé O. , Fritz N.
Published: May 2010

Abstract. In this work, the rich dataset acquired at the SMOSREX experimental site is used to enhance the A-gs version of the Interactions between Soil, Biosphere and Atmosphere (ISBA) model. A simple representation of the soil moisture effect on the ecosystem respiration is implemented in the ISBA-A-gs model. It results in an improvement of the modelled CO2 flux over a grassland in southwestern France. The former temperature-only dependent respiration formulation used in ISBA-A-gs is not able to model the limitation of the respiration under dry conditions. In addition to soil moisture and soil temperature, the only parameter required in this formulation is the ecosystem respiration parameter Re25. It can be estimated by means of eddy covariance measurements of turbulent nighttime CO2 flux (i.e. ecosystem respiration). The resulting correlation between observed and modelled net ecosystem exchange is r2=0.63 with a bias of −2.18 μmol m−2 s−1. It is shown that when CO2 observations are not available, it is possible to use a more complex model, able to represent the heterotrophic respiration and all the components of the autotrophic respiration, to estimate Re25 with similar results. The modelled ecosystem respiration estimates are provided by the Carbon Cycle (CC) version of ISBA (ISBA-CC). ISBA-CC is a version of ISBA able to simulate all the respiration components, whereas ISBA-A-gs uses a single equation for ecosystem respiration. ISBA-A-gs is easier to handle and more convenient than ISBA-CC for the practical use in atmospheric or hydrological models. Surface water and energy flux observations, as well as Gross Primary Production (GPP) estimates, are compared with model outputs. The dependence of GPP to air temperature is investigated. The observed GPP is less sensitive to temperature than the modelled GPP. Finally, the simulations of the ISBA-A-gs model are analysed over a seven year period (2001–2007). Modelled soil moisture and Leaf Area Index (LAI) are confronted with the observed surface and root-zone soil moisture content (m3 m−3), and with LAI estimates derived from surface reflectance measurements.
Influence of resin viscosity and vacuum level on mechanical performance of sandwich structures manufactured by vacuum bagging
Authors: Valenza A. , Fiore V.
Published: May 2010

The choice of process parameters is critical in optimizing the mechanical properties of sandwich structures produced using the vacuum bagging technique. The aim of this paper is to analyze how the viscosity of the resin/curing agent system and the vacuum level influence the morphology and the mechanical behavior of sandwich beams with composite faces (epoxy resin and glass fiber fabric named COMBI 900) and a PVC foam core. Four different sandwich structures were produced by varying the viscosity of the epoxy resin/curing agent at constant maximum vacuum pressure. Three further structures were manufactured by varying the strength of the vacuum with the resin viscosity maintained constant at the minimum level. Three point bending tests were carried out on all seven sandwiches. The analysis shows that although both parameters affect the mechanical characteristics of the structure, the viscosity of the resin system is clearly the more influential of the two. The morphological structure of the sandwiches was analyzed both by scanning electron microscope (SEM) and by muffle furnace ignition to calculate the percentage of fibers, matrices, and voids present in the different samples © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:20–30, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20172
Synthesis of 3,4‐Diarylsubstituted Maleic Anhydride/Maleimide via Unusual Oxidative Cyclization of Phenacyl Ester/Amide.
Authors: Pattabiraman Vijaya Raghavan , Padakanti Srinivas , Veeramaneni Venugopal Rao , Pal Manojit , Yeleswarapu Koteswar Rao
Published: May 2010

For Abstract see ChemInform Abstract in Full Text.
Aromatic Farnesyl Diphosphate Analogues: Vinyl Triflate‐Mediated Synthesis and Preliminary Enzymatic Evaluation.
Authors: Zhou Chunmei , Shao Ying , Gibbs Richard A.
Published: May 2010

For Abstract see ChemInform Abstract in Full Text.
The First Total Synthesis of 2,3,6‐Tribromo‐4,5‐dihydroxybenzyl Methyl Ether (TDB) and Its Antioxidant Activity.
Authors: Kim Jae‐Kon , Noh Jung Hyun , Lee Sungeun , Choi Jae Sue , Suh Hongsuk , Chung Hae Young , Song Yeong‐Ok , Choi Won Chul
Published: May 2010

For Abstract see ChemInform Abstract in Full Text.
Combinatorial Synthesis: Solution—Phase Synthesis and Solid‐Phase Split & Mix Synthesis
Authors: Fukase Koichi
Published: May 2010

For Abstract see ChemInform Abstract in Full Text.
Hydrogen Bridges in Crystal Engineering: Interactions Without Borders
Authors: Desiraju Gautam R.
Published: May 2010

For Abstract see ChemInform Abstract in Full Text.
Recent Advances on the Synthetic Applications of the Dithioacetal Functionality.
Authors: Luh Tien‐Yau
Published: May 2010

For Abstract see ChemInform Abstract in Full Text.
Heterocyclic Analogues of Pleiadiene. Part 69. Synthesis and Oxidative Hydroxylation of 1‐Alkyl‐1,3‐diazapyrenium Salts.
Authors: Borovlev I. V. , Demidov O. P. , Chernyshev A. V. , Pozharskii A. F.
Published: May 2010

For Abstract see ChemInform Abstract in Full Text.
Synthesis and Investigation of L‐Fuco‐ and D‐Glucurono‐azafagomine.
Authors: Jensen Henrik H. , Jensen Astrid , Hazell Rita G. , Bols Mikael
Published: May 2010

For Abstract see ChemInform Abstract in Full Text.
Asymmetric Organometallic‐Catalyzed Reactions in Aqueous Media
Authors: Sinou Denis
Published: May 2010

For Abstract see ChemInform Abstract in Full Text.
Searching for New Reactivity (Nobel Lecture)
Authors: Sharpless K. Barry
Published: May 2010

For Abstract see ChemInform Abstract in Full Text.
A similarity-index–based method to estimate chemical concentration limits protective for ecological communities
Authors: Kefford Ben J. , Schäfer Ralf B. , Liess Matthias , Goonan Peter , Metzeling Leon , Nugegoda Dayanthi
Published: May 2010

A new method is presented to determine retrospectively proportional changes of species composition in a community at risk from particular concentrations of chemical stressors. The method makes estimates with some similarities to those claimed by species sensitivity distributions (SSDs) but is based on species presence/absence field data and requires assumptions that are more likely to be met. The method uses Jaccard's index (JI), the proportion of species in common to two samples. At a similar level of contamination, the occurrence of species is usually highly variable, and thus JI values between individual pairs of samples can be low. However, by pooling samples with a similar contamination level, an increasingly complete set of species present at this level of contamination is gained. Our method involves calculating JI between randomly selected groups of samples (pooled sample sets) with similar and different levels of contamination. It then relates changes in JI to the difference in contamination and produces estimates of the proportional change in species between preselected categories of contamination. The application of the method is illustrated by using data on riverine freshwater macroinvertebrates exposed to salinity in southeastern Australia; pesticide runoff potential in the Aller River Catchment, Germany; and metal pollution (principle Cu) in the Clark Fork River Catchment, Montana, USA. Environ. Toxicol. Chem. 2010;29:2123–2131. © 2010 SETAC
The moment‐guided Monte Carlo method
Authors: Degond Pierre , Dimarco Giacomo , Pareschi Lorenzo
Published: May 2010

In this work we propose a new approach for the numerical simulation of kinetic equations through Monte Carlo schemes. We introduce a new technique that permits to reduce the variance of particle methods through a matching with a set of suitable macroscopic moment equations. In order to guarantee that the moment equations provide the correct solutions, they are coupled to the kinetic equation through a nonequilibrium term. The basic idea, on which the method relies, consists in guiding the particle positions and velocities through moment equations so that the concurrent solution of the moment and kinetic models furnishes the same macroscopic quantities. Copyright © 2010 John Wiley & Sons, Ltd.
A lattice Boltzmann model for two‐dimensional sound wave in the small perturbation compressible flows
Authors: Zhang Jianying , Yan Guangwu , Yan Bo , Shi Xiubo
Published: May 2010

A multi‐entropy‐level lattice Boltzmann model for two‐dimensional sound wave equation in the small perturbation flows is presented. In this model, we used higher‐order moment method, multi‐scale technique and the Chapman–Enskog expansion, and multi‐entropy‐level to obtain sound wave equation with isentropic equation. As numerical examples, the Doppler effects in the sound wave propagation, the sound scattering from circular cylinder are simulated. The numerical results show that this model can be used to simulate sound wave propagation. Copyright © 2010 John Wiley & Sons, Ltd.
A comparative study of various pressure relaxation closure models for one‐dimensional two‐material Lagrangian hydrodynamics
Authors: Kamm J. R. , Shashkov M. J. , Fung J. , Harrison A. K. , Canfield T. R.
Published: May 2010

Lagrangian hydrodynamics of strength‐free materials continues to present open issues, even in one dimension. We focus on the problem of closing a system of equations for a two‐material cell under the assumption of a single velocity model. There are several existing models and approaches, each possessing different levels of fidelity to the underlying physics and each exhibiting unique features in the computed solutions. We consider three models that take different approaches to breaking the assumption of instantaneous pressure equilibration in the mixed‐material cell. The first of these is the well‐known method of Tipton, in which a viscosity‐like pressure relaxation term is coupled with an otherwise isentropic pressure update to obtain closed‐form expressions for the materials' volume fractions and corresponding sub‐cell pressures. The second is the physics‐inspired, geometry‐based pressure relaxation model of Kamm and Shashkov, which is based on an optimization procedure that uses a local, exact Riemann problem. The third model is the unique aspect of this paper, inspired by the work of Delov and Sadchikov and Goncharov and Yanilkin. This sub‐scale dynamics approach is motivated by the linearized Riemann problem to initialize volume fraction changes, which are then modified, via the materials' SIEs, to drive the mixed cell toward pressure equilibrium. Each of these approaches is packaged in the framework of a two‐step time integration scheme. We compare these multi‐material pressure relaxation models, together with corresponding pure‐material calculations, on idealized, two‐material problems with either ideal‐gas or stiffened‐gas equations of state. Published in 2010 by John Wiley & Sons, Ltd.
MRI quantification of non‐Gaussian water diffusion by kurtosis analysis
Authors: Jensen Jens H. , Helpern Joseph A.
Published: May 2010

Quantification of non‐Gaussianity for water diffusion in brain by means of diffusional kurtosis imaging (DKI) is reviewed. Diffusional non‐Gaussianity is a consequence of tissue structure that creates diffusion barriers and compartments. The degree of non‐Gaussianity is conveniently quantified by the diffusional kurtosis and derivative metrics, such as the mean, axial, and radial kurtoses. DKI is a diffusion‐weighted MRI technique that allows the diffusional kurtosis to be estimated with clinical scanners using standard diffusion‐weighted pulse sequences and relatively modest acquisition times. DKI is an extension of the widely used diffusion tensor imaging method, but requires the use of at least 3 b‐values and 15 diffusion directions. This review discusses the underlying theory of DKI as well as practical considerations related to data acquisition and post‐processing. It is argued that the diffusional kurtosis is sensitive to diffusional heterogeneity and suggested that DKI may be useful for investigating ischemic stroke and neuropathologies, such as Alzheimer's disease and schizophrenia. Copyright © 2010 John Wiley & Sons, Ltd.
Proton MRS of large multiple sclerosis lesions reveals subtle changes in metabolite T1 and area
Authors: Brief E. E. , Vavasour I. M. , Laule C. , Li D. K. B. , MacKay A. L.
Published: May 2010

The T1 values of metabolites were measured in eight subjects with clinically definite multiple sclerosis (MS) having at least one large brain lesion (2.6 ± 0.7 mL) and in eight age‐ and sex‐matched healthy controls. MRS examinations were conducted at 1.5 T using point‐resolved spectroscopy (PRESS) (TE = 30 ms, TR = 530, 750, 1200, 1500, 3500, 5000 ms). Spectra were acquired from a voxel placed in the largest lesion in the subject with MS, and in a corresponding voxel (same size and region) in normal white matter (NWM) in the matched control, and were fitted using LCModel. As there are regional variations in metabolite and water T1 and metabolite signal areas, careful placement of the control voxel was necessary to measure subtle differences between the lesions and NWM. The T1 and T1‐corrected signal areas of creatine were the same in MS lesions as in controls. The T1 values of choline were significantly shorter in MS lesions located in occipital and parietal, but not in frontal, white matter. N‐Acetylaspartate (NAA) and myoinositol T1 values in MS lesions were similar to those in NWM; however, the area of myoinositol correlated directly with lesion water T1, and the area of NAA correlated inversely with lesion water T1. MR spectra acquired at short TR require T1 correction of choline for accurate quantification. Careful voxel placement in controls to match lesion location in subjects with MS enables a clearer view of the subtle changes in lesions. Copyright © 2010 John Wiley & Sons, Ltd.
Improvement of resolution for brain coupled metabolites by optimized 1H MRS at 7 T
Authors: Choi Changho , Dimitrov Ivan E. , Douglas Deborah , Patel Aditya , Kaiser Lana G. , Amezcua Carlos A. , Maher Elizabeth A.
Published: May 2010

Resolution enhancement for glutamate (Glu), glutamine (Gln) and glutathione (GSH) in the human brain by TE‐optimized point‐resolved spectroscopy (PRESS) at 7 T is reported. Sub‐TE dependences of the multiplets of Glu, Gln, GSH, γ‐aminobutyric acid (GABA) and N‐acetylaspartate (NAA) at 2.2–2.6 ppm were investigated with density matrix simulations, incorporating three‐dimensional volume localization. The numerical simulations indicated that the C4‐proton multiplets can be completely separated with (TE1, TE2) = (37, 63) ms, as a result of a narrowing of the multiplets and suppression of the NAA 2.5 ppm signal. Phantom experiments reproduced the signal yield and lineshape from simulations within experimental errors. In vivo tests of optimized PRESS were conducted on the prefrontal cortex of six healthy volunteers. In spectral fitting by LCModel, Cramér–Rao lower bounds (CRLBs) of Glu, Gln and GSH were 2 ± 1, 5 ± 1 and 6 ± 2 (mean ± SD), respectively. To evaluate the performance of the optimized PRESS method under identical experimental conditions, stimulated‐echo spectra were acquired with (TE, TM) = (14, 37) and (74, 68) ms. The CRLB of Glu was similar between PRESS and short‐TE stimulated‐echo acquisition mode (STEAM), but the CRLBs of Gln and GSH were lower in PRESS than in both STEAM acquisitions. Copyright © 2010 John Wiley & Sons, Ltd.
Simulation of fragmentation of arginine molecule aggregate by quantum molecular dynamics for TOF‐SIMS spectral analysis
Authors: Kato N. , Kudo M.
Published: May 2010

For detailed analysis of fragmentation of organic molecules in TOF‐SIMS spectra, fragmentation process of an arginine molecule was simulated by using the quantum molecular dynamics (QMD) method. In this simulation which was assumed as thermal decomposition process, thermal energies given to an arginine molecule were 0.17, 0.34, 0.51, 0.69 and 0.86 eV. In the simulation which was assumed as molecular collision process, collision energies between two arginine molecules were 50 and 100 eV. Molecular mass and number of fragment molecules resulted from these simulations were compared to mass and intensity of fragments in experimental TOF‐SIMS spectra of arginine. Copyright © 2010 John Wiley & Sons, Ltd.
ToF‐SIMS characterization of the lipid layer on the hair surface. II : Effect of the 18‐MEA lipid layer on surface hydrophobicity
Authors: Okamoto Masayuki , Tanji Noriyuki , Habe Taichi , Inoue Shigeto , Tokunaga Shinichi , Tanamachi Hiroto
Published: May 2010

In this study, the effect of the damage level of 18‐MEA on the hydrophobicity of hair surfaces and the mechanism of technology for replenishment of the lipid on damaged hair surfaces were examined using Time‐of‐Flight Secondary Ion Mass Spectrometry (ToF‐SIMS). The surface amount of 18‐MEA was measured in Japanese women by ToF‐SIMS. It was obvious that the 18‐MEA was decreased drastically by coloring treatments, especially in individuals who underwent such treatments more than two times per year. Additionally, even in hair without any chemical treatments, more than 80 percent of 18‐MEA was removed at the portion 40 cm from the hair root. The relationship between the surface contact angle of the hair fiber and the 18‐MEA amount showed that 18‐MEA played an important role in surface hydrophobicity. It was found that, as a replenishment technology of the surface lipid layer, 18‐MEA conditioner treatment combined with a specific cationic surfactant (Stearoxypropyldimethylamine: SPDA) effectively results in persistent hydrophobicity and low friction on damaged hair surfaces. ToF‐SIMS analyses revealed that the homogeneous adsorption layer provided by 18‐MEA/SPDA treatment resulted in effective hydrophobicity in damaged hair. Copyright © 2010 John Wiley & Sons, Ltd.
Bin+ cluster ion sources for investigation of a covalently immobilized mixed film composed of oligonucleotides and poly(2‐hydroxyethyl methacrylate) brushes
Authors: Wong April K. Y. , Sodhi R. N. S. , Krull Ulrich J.
Published: May 2010

The ability of Bin+ cluster ion sources to provide information about the physical structure of an integrated film composed of oligonucleotides and non‐nucleic acid oligomers of poly(2‐hydroxyethyl methacrylate) (PHEMA) has been explored using static time‐of‐flight (ToF) SIMS (ToF‐SIMS). Fragment intensities from PHEMA and oligonucleotides were compared. Negative ion spectra indicated that the Bi5+ source provided details that were either not apparent or at much reduced sensitivity when using Bi3+ and Bi+ sources. The Bi3+ ion source provided higher secondary ion intensities for positive ion fragments, and more than 200‐fold selectivity for ionization of oligonucleotide in comparison to PHEMA when in mixture, even though the oligonucleotides were not immobilized as a coating superimposed on PHEMA. Copyright © 2010 John Wiley & Sons, Ltd.
Three‐dimensional reconstruction of a nickel‐ alumina composite coating by FIB‐SIMS
Authors: Chater Richard J. , Corni Ilaria , Boccaccini Aldo R. , Ryan Mary P.
Published: May 2010

The alumina particle distribution in a nickel‐alumina composite coating on stainless steel was determined using the aluminum secondary ion images that were generated by sputtering a cross‐section of the coating with a highly focused gallium primary ion beam (FIB). Thin slices of the coating were removed using the same beam with further imaging of the fresh surface which was very smooth despite the difference in the sputter rates of the two materials. Sequential SIMS imaging and sectioning resulted in a sequence of images from which the 3D distribution of the alumina particles in the composite coating was reconstructed. Copyright © 2010 John Wiley & Sons, Ltd.
Molecular and cellular events of dopamine D1 receptor‐mediated tau phosphorylation in SK‐N‐MC cells
Authors: Lebel Manon , Cyr Michel
Published: May 2010

Microtubules are involved in the formation of axons and dendrites, maintenance of neuronal morphology, and cellular trafficking. Recent studies suggest that drugs affecting dopamine activity in the brain can induce cytoskeletal modifications. For instance, we have demonstrated in acute rat brain slices a molecular chain of events connecting dopamine D1 receptor to aberrant phosphorylation of the microtubule‐associated protein tau. However, the molecular and cellular effects of tau phosphorylated by means of the activation of dopamine receptors were unexplored. Here we used SK‐N‐MC cells, which express endogenously functional D1 receptors, to demonstrate that levels of phosphorylated tau at serines 199–202 or 214 are increased by a calcium‐dependent pathway subsequent to D1 receptor stimulation. Using selective pharmacological tools, we showed that enhanced intracellular calcium lead to cyclin‐dependent kinase 5 (cdk5) activation, by calpain proteolysis of p35 to p25, as well as glycogen synthase kinase 3β (GSK3β) activation, by its phosphorylation at tyrosine 216. Interestingly, while the activation of protein kinase A (PKA) led directly to the phosphorylation of tau at serine 214, tau phosphorylation at serines 199–202 was independent of PKA. In addition, inhibition of cdk5 or GSK3β prevented the decrease in cell viability induced by D1 receptor stimulation whereas PKA inhibition had no influence. Our data demonstrate that activation of cdk5 and GSK3β following D1 receptor stimulation could have profound influence on both the neuronal cytoskeletal constituent tau and cell survival in SK‐N‐MC cells. Synapse 65:69–76, 2011. © 2010 Wiley‐Liss, Inc.
A modified lipid composition in Fabry disease leads to an intracellular block of the detergent‐resistant membrane‐associated dipeptidyl peptidase IV
Authors: Maalouf Katia , Jia Jia , Rizk Sandra , Brogden Graham , Keiser Markus , Das Anibh , Naim Hassan Y.
Published: May 2010

Fabry disease is an X‐linked lysosomal storage disorder that leads to abnormal accumulation of glycosphingolipids due to a deficiency of alpha‐galactosidase A (AGAL). The consequences of these alterations on the targeting of membrane proteins are poorly understood. Glycosphingolipids are enriched in Triton‐X‐100‐ resistant lipid rafts [detergent‐resistant membranes (DRMs)] and play an important role in the transport of several membrane‐associated proteins. Here, we show that In fibroblasts of patients suffering from Fabry disease, the colocalization of AGAL with the lysosomal marker LAMP2 is decreased compared with wild‐type fibroblasts concomitant with a reduced transport of AGAL to lysosomes. Furthermore, overall composition of membrane lipids in the patients’ fibroblasts as well as in DRMs reveals a substantial increase in the concentration of glycolipids and a slight reduction of phosphatidylethanolamine (PE). The altered glycolipid composition in Fabry fibroblasts is associated with an intracellular accumulation and impaired trafficking of the Triton‐X‐100 DRM‐associated membrane glycoprotein dipeptidyl peptidase IV (DPPIV) in transfected Fabry cells, whereas no effect could be observed on the targeting of aminopeptidase N (ApN) that is not associated with this type of DRM. We propose that changes in the lipid composition of cell membranes in Fabry disease disturb the ordered Triton X‐100 DRMs and have implications on the trafficking and sorting of DRM‐associated proteins and the overall protein–lipid interaction at the cell membrane. Possible consequences could be altered signalling at the cell surface triggered by DRM‐associated proteins, with implications on gene regulation and subsequent protein expression.
A unique association between cognitive inhibition and pain sensitivity in healthy participants
Authors: Oosterman Joukje M. , Dijkerman H. Chris , Kessels Roy P.C. , Scherder Erik J.A.
Published: May 2010

The experience of pain constitutes a complex phenomenon that is determined by and reflects the interplay of many factors, including cognitive functions. Little is known, however, about the precise role of executive functions in pain sensitivity. Importantly, these functions may be directly related to the ability to control pain. The present study evaluated the relationship between pain sensitivity and executive functions in a sample of healthy volunteers. Pain sensitivity was assessed with the cold pressor test. The immersion time, here defined as the time until substantial pain was reported, was measured. Additional pain intensity and pain unpleasantness ratings were obtained as an indication of pain experience. The results revealed a unique association between cognitive inhibition (i.e. the Stroop interference score), but not other executive functions, and immersion time, pain intensity, and pain unpleasantness. Specifically, better cognitive inhibition was related to a reduction in pain sensitivity as evident by an increased immersion time and decreased pain intensity and pain unpleasantness ratings. As such, cognitive inhibition may be an important determinant of pain sensitivity.
Sucht ist ein Public Health-Problem
Authors: Hanewinkel Reiner , Morgenstern Matthis
Published: May 2010

„Einleitung“

Die negativen gesundheitlichen Auswirkungen, die der Konsum von Tabak und Alkohol nach sich ziehen kann, sind bereits seit längerer Zeit bekannt. Aber erst die Entwicklung moderner epidemiologischer Methoden ermöglichte die Abschätzung der Folgen von Suchterkrankungen auf die Volksgesundheit. Weltweit steht der Tabakkonsum an zweiter Stelle der Todesursachenstatistik stand, gefolgt von dem Alkoholkonsum auf neunter und dem Missbrauch illegaler Drogen an 17. Position.
Genetische Disposition für die Entwicklung von Sucht
Authors: Heimann Hannah , Puls Imke , Heinz Andreas
Published: May 2010

Einleitung

Abhängigkeitserkrankungen sind psychische Erkrankungen, die für die Betroffenen weitreichende Konsequenzen haben. Das Ziel der Erforschung möglicher genetischer Faktoren für die Entwicklung einer Sucht ist es, Erkenntnisse über die Ätiologie dieser Erkrankungen zu gewinnen und zielgenauere Therapieformen zu entwickeln. Zur Untersuchung der Rolle genetischer Faktoren stehen verschiedene Strategien zur Verfügung, welche in diesem Artikel vorgestellt werden.
Lerntheoretische Erklärungsansätze zur Entstehung und Aufrechterhaltung von Suchtverhalten
Authors: Beck Anne , Heinz Andreas
Published: May 2010

Einleitung

Alkoholabhängigkeit ist eine der schwerwiegendsten psychischen Erkrankungen bei Männern in westlichen Industrienationen (WHO, 2008), wobei in Deutschland ca. 1,3 Millionen Menschen als abhängig gelten (DHS, 2009). Die Rückfallraten sind auch nach Abklingen der körperlichen Entzugssymptome mit ca. 85% sehr hoch (Boothby und Doering, 2005). Seit Jahrzehnten beschäftigt sich die lerntheoretische Suchtforschung damit, die auslösenden und aufrechterhaltenden Faktoren dieser Suchterkrankung zu analysieren.
Gender Mainstreaming in der Suchthilfe
Authors: Ernst Marie-Louise
Published: May 2010

Einleitung

Neben dem Alter, der sozialen Herkunft und dem Migrationshintergrund ist Gender auch im Suchtbereich ein wesentlicher Einflussfaktor in Bezug auf Konsummuster, Ursachen einer Suchtentwicklung, Suchtverläufen und Ausstiegsszenarien bei Frauen und Männern.
Suchtprobleme im höheren Lebensalter
Authors: Weyerer Siegfried
Published: May 2010

Einleitung

Dem Thema Sucht im höheren Alter wurde lange Zeit wenig Aufmerksamkeit geschenkt (Havemann-Reinecke et al., 1998, Weyerer und Bickel, 2007). Mit der sich ändernden Bevölkerungsstruktur nimmt jedoch die Bedeutung von Suchterkrankungen im Alter zu. In dieser Arbeit sollen - bezogen auf ältere Menschen - der Gebrauch und Missbrauch von drei quantitativ bedeutsamen Substanzgruppen skizziert werden: Medikamente (vor allem Benzodiazepine), Alkohol und Tabak.
Medienabhängigkeit bei Kindern und Jugendlichen - neue vielseitige Herausforderungen
Authors: Putzig Inken , Wedegärtner Felix , Wildt Bert Theodor te
Published: May 2010

Einleitung

Jede neue technologische Entwicklung scheint anfänglich die Frage nach einem vermeintlichen Abhängigkeitspotenzial aufzuwerfen, welches sich rückblickend zumeist nicht bestätigen ließ. Die Konvergenz aller analogen Vorläufermedien in einem digitalen Großmedium sowie die neuartige Interaktivität im Cyberspace und in Computerspielen bieten eine Erklärung dafür, warum die Mediennutzung im klinischen Sinne erstmals in eine Abhängigkeit führen kann.
Sucht und Werbung – Hat Werbung einen Einfluss auf den Konsum von Suchtmitteln?
Authors: Morgenstern Matthis , Isensee Barbara , Hanewinkel Reiner
Published: May 2010

Einleitung

Die Frage danach, ob Werbung für legale Suchtmittel den Konsum von Suchtmitteln befördert, wird nach wie vor diskutiert. Befunde bisheriger empirischer Studien sprechen konsistent für eine solche Wirkung. Der Beitrag erörtert mögliche Gründe für ein Anhalten der Diskussion.