Showing papers by "University of Twente published in 2007"
TL;DR: The rheumatologic community is in a leading position for the development of International Classification of Functioning, Disability and Health (ICF) Core Sets and the research into the validity and application of the ICF, but not all of us are aware of this new development.
Abstract: The rheumatologic community is in a leading position for the development of International Classification of Functioning, Disability and Health (ICF) Core Sets and the research into the validity and application of the ICF We can be proud of this achievement, but not all of us are aware of this new development What is the ICF? Rheumatologic conditions have major impact on patients Apart from symptoms such as pain, stiffness, and fatigue, patients are limited in activities and restricted in participation in society [2] When unable to continue paid work, for example, there are important consequences for the patients, their families, but also for society A major goal of the management of rheumatic diseases is to maintain or restore functioning This contributes to the well-being of the patients, their families, and other caregivers It is clear that maintaining function requires more than control of disease activity By using the ICF, which was developed by the World Health Organization (WHO), we can obtain information on all three areas that are important for global functioning: body functions and structures, activities (actions by an individual), and participation (involvement in life situations) [3] The ICF is one of the three reference classification systems that were proposed and developed by the WHO and belong to the Family of International Classifications The main aim of the classification systems is to improve integration of health information The International Classification of Diagnosis (ICD) is well known and widely applied [4] The ICF was developed from the older International Classification of Impairments, Disabilities, and Handicaps (ICIDH) and accepted in 2001 [3] It is increasingly recognized as an important classification in clinical medicine, outcome research, and healthcare organization The International Classification of Health Interventions (ICHI) is proposed as the newest member of the family, and its development has just started [1] The WHO aims to implement effectively the ICF worldwide and formulated strategic directions in which the three following are the most relevant: (1) The ICF has to become the framework to classify function, (2) easy-to-use ICF linked instruments should be developed to assess functional outcome as well as effectiveness of interventions, and (3) the level and quality of implementation of the ICF should be improved to increase quality and comparability Clin Rheumatol (2007) 26:1803–1808 DOI 101007/s10067-007-0623-0
1,653 citations
TL;DR: Focusing of coherent light through opaque scattering materials by control of the incident wavefront with a brightness up to a factor of 1000 higher than the brightness of the normal diffuse transmission is reported.
Abstract: We report focusing of coherent light through opaque scattering materials by control of the incident wavefront. The multiply scattered light forms a focus with a brightness that is up to a factor of 1000 higher than the brightness of the normal diffuse transmission.
1,624 citations
17 Sep 2007
TL;DR: Electromyography (EMG) measurements on eight important leg muscles, show that free walking in the device strongly resembles free treadmill walking; an indication that the device can offer task-specific gait training.
Abstract: This paper introduces a newly developed gait rehabilitation device. The device, called LOPES, combines a freely translatable and 2-D-actuated pelvis segment with a leg exoskeleton containing three actuated rotational joints: two at the hip and one at the knee. The joints are impedance controlled to allow bidirectional mechanical interaction between the robot and the training subject. Evaluation measurements show that the device allows both a "pa- tient-in-charge" and "robot-in-charge" mode, in which the robot is controlled either to follow or to guide a patient, respectively. Electromyography (EMG) measurements (one subject) on eight important leg muscles, show that free walking in the device strongly resembles free treadmill walking; an indication that the device can offer task-specific gait training. The possibilities and limitations to using the device as gait measurement tool are also shown at the moment position measurements are not accurate enough for inverse-dynamical gait analysis.
1,150 citations
TL;DR: The characteristics of human motion analysis are discussed to highlight trends in the domain and to point out limitations of the current state of the art.
908 citations
TL;DR: Current protein immobilization strategies, including physical, covalent, and bioaffinity immobilization for the fabrication of protein biochips, are described and particular consideration has been given to oriented immobilization, also referred to as site-specific immobilized, which is believed will improve homogeneous surface covering and accessibility of the active site.
861 citations
TL;DR: This paper reviews the use of discrete particle models for the study of the flow phenomena prevailing in fluidized beds and describes the gas-phase as a continuum, whereas each of the individual particles is treated as a discrete entity.
847 citations
TL;DR: In this article, extensive lattice Boltzmann simulations were performed to obtain the drag force for random arrays of monodisperse and bidisperse spheres, and a new drag law was suggested for general polydisperse systems.
Abstract: Extensive lattice-Boltzmann simulations were performed to obtain the drag force for random arrays of monodisperse and bidisperse spheres. For the monodisperse systems, 35 different combinations of the Reynolds number Re (up to Re = 1,000) and packing fraction were studied, whereas for the bidisperse systems we also varied the diameter ratio (from 1:1.5 to 1:4) and composition, which brings the total number of different systems that we considered to 150. For monodisperse systems, the data was found to be markedly different from the Ergun equation and consistent with a correlation, based on similar type of simulations up to Re = 120. For bidisperse systems, it was found that the correction of the monodisperse drag force for bidispersity, which was derived for the limit Re = 0, also applies for higher-Reynolds numbers. On the basis of the data, a new drag law is suggested for general polydisperse systems, which is on average within 10% of the simulation data for Reynolds numbers up to 1,000, and diameter ratios up to 1:4
696 citations
TL;DR: The taper and the diameter of the root canal were found to be important parameters in determining the efficacies of dentine debris removal and the role of cavitation during PUI remains inconclusive.
Abstract: Ultrasonic irrigation of the root canal can be performed with or without simultaneous ultrasonic instrumentation. When canal shaping is not undertaken the term passive ultrasonic irrigation (PUI) can be used to describe the technique. In this paper the relevant literature on PUI is reviewed from a MEDLINE database search. Passive ultrasonic irrigation can be performed with a small file or smooth wire (size 10-20) oscillating freely in the root canal to induce powerful acoustic microstreaming. PUI can be an important supplement for cleaning the root canal system and, compared with traditional syringe irrigation, it removes more organic tissue, planktonic bacteria and dentine debris from the root canal. PUI is more efficient in cleaning canals than ultrasonic irrigation with simultaneous ultrasonic instrumentation. PUI can be effective in curved canals and a smooth wire can be as effective as a cutting K-file. The taper and the diameter of the root canal were found to be important parameters in determining the efficacies of dentine debris removal. Irrigation with sodium hypochlorite is more effective than with water and ultrasonic irrigation is more effective than sonic irrigation in the removal of dentine debris from the root canal. The role of cavitation during PUI remains inconclusive. No detailed information is available on the influence of the irrigation time, the volume of the irrigant, the penetration depth of the instrument and the shape and material properties of the instrument. The influence of irrigation frequency and intensity on the streaming pattern as well as the complicated interaction of acoustic streaming with the adherent biofilm needs to be clarified to reveal the underlying physical mechanisms of PUI.
615 citations
TL;DR: In this paper, two membrane-based energy conversion techniques are evaluated: pressure-retarded osmosis and reverse electrodialysis, with respect to power density and energy recovery.
535 citations
TL;DR: Risk perception, personal experience, perceived behavioural control and subjective norm were found to significantly predict the perceived usefulness of electronic services in general, while trust in e-government was the main determinant of the perception usefulness of e- government services.
520 citations
TL;DR: In this paper, the authors conducted a meta-analysis to identify the 24 most widely researched success factors for NTVs and found that among the 24 possible success factors identified in the literature, 8 are homogeneous significant success factors.
TL;DR: A layered implementation model is proposed in which the primary focus on individual determinants changes throughout the development life cycle of the telemedicine implementation.
Abstract: Telemedicine implementations often remain in the pilot phase and do not succeed in scaling-up to robust products that are used in daily practice. We conducted a qualitative literature review of 45 conference papers describing telemedicine interventions in order to identify determinants that had influenced their implementation. The identified determinants, which would influence the future implementation of telemedicine interventions, can be classified into five major categories: (i) Technology, (ii) Acceptance (iii) Financing, (iv) Organization and (v) Policy and Legislation. Each category contains determinants that are relevant to different stakeholders in different domains. We propose a layered implementation model in which the primary focus on individual determinants changes throughout the development life cycle of the telemedicine implementation. For success, a visionary approach is required from the multidisciplinary stakeholders, which goes beyond tackling specific issues in a particular development phase. Thus the right philosophy is: ‘start small, think big’.
01 Jul 2007
TL;DR: In this article, the issues for national policy and for individual institutions are discussed, focusing on Europeanisation, institutional rankings and typologies, and cross-border mobility in higher education.
Abstract: Economic and cultural globalisation has ushered in a new era in higher education. Higher education was always more internationally open than most sectors because of its immersion in knowledge, which never showed much respect for juridical boundaries. In global knowledge economies, higher education institutions are more important than ever as mediums for a wide range of cross-border relationships and continuous global flows of people, information, knowledge, technologies, products and financial capital. Even as they share in the reinvention of the world around them, higher education institutions, and the
policies that produce and support them, are also being reinvented. For the first time in history every research university is part of a single world-wide network and the world leaders in the field have an unprecedented global visibility and power. Research is more internationalised than before and the mobility of doctoral students and faculty has increased. The specifically global element in academic labour markets has gained weight, especially since the advent of global university rankings. This working paper explores the issues for national policy and for individual institutions. Part I provides an overview of globalisation and higher education and the global responses of national systems and individual institutions of higher education. Part II is focused on certain areas of policy with a strong multilateral dimension: Europeanisation, institutional rankings and typologies and cross-border mobility.
TL;DR: Results demonstrate that enzymatic crosslinking is an efficient way to obtain fast in situ formation of hydrogels that are promising for use as injectable systems for biomedical applications including tissue engineering and protein delivery.
TL;DR: Cell‐ and growth‐factor based tissue engineering provides a promising alternative to natural bone grafts; however, the performance of tissue‐engineered constructs often depends on the used carrier.
Abstract: The need for bone tissue regeneration is continuously expanding due to the improvement of life quality and the consequent increase in life expectancy. Although natural bone grafts have shown excellent clinical successes, their use is associated with some important drawbacks, limited availability being one of the most important. Cell- and growth-factor based tissue engineering provides a promising alternative to natural bone grafts; however, the performance of tissue-engineered constructs often depends on the used carrier.
An important challenge in the field of bone regeneration is the development of synthetic bone graft substitutes that are intelligent in that they are able to instruct the in vivo environment to form bone. A group of potentially intelligent bone graft substitutes are osteoinductive biomaterials.
In this paper, background on the phenomenon of osteoinduction and an overview of synthetic biomaterials with osteoinductive potential are given. Furthermore, we elaborate on physicochemical properties of biomaterials that are of influence on their osteoinductive potential. Finally, we discuss the relevance of osteoinductivity of biomaterials in the repair of clinically relevant bone defects.
TL;DR: The presented anatomical dataset embraces all necessary data for state of the art musculoskeletal modelling of the lower extremity, and implementation of these data into an (existing) model is likely to significantly improve the estimation of muscle forces.
TL;DR: A method that uses constraints in the elbow to measure the orientation of the lower arm with respect to the upper arm is described, but the accuracy is limited by the accuracy of the sensor to segment calibration.
TL;DR: The theoretical foundations of the Shan-Chen methodology for the lattice Boltzmann method are clarified and its applicability and flexibility to the simulation of multiphase flows to density ratios up to O(100).
Abstract: The physical behavior of a class of mesoscopic models for multiphase flows is analyzed in details near interfaces. In particular, an extended pseudopotential method is developed, which permits to tune the equation of state and surface tension independently of each other. The spurious velocity contributions of this extended model are shown to vanish in the limit of high grid refinement and/or high order isotropy. Higher order schemes to implement self-consistent forcings are rigorously computed for 2d and 3d models. The extended scenario developed in this work clarifies the theoretical foundations of the Shan-Chen methodology for the lattice Boltzmann method and enhances its applicability and flexibility to the simulation of multiphase flows to density ratios up to O(100).
TL;DR: The design and testing of a portable magnetic system combined with miniature inertial sensors for ambulatory 6 degrees of freedom ( DOF) human motion tracking is presented and an optimal solution for position and orientation estimates is obtained.
Abstract: This paper presents the design and testing of a portable magnetic system combined with miniature inertial sensors for ambulatory 6 degrees of freedom ( DOF) human motion tracking. The magnetic system consists of three orthogonal coils, the source, fixed to the body and 3-D magnetic sensors, fixed to remote body segments, which measure the fields generated by the source. Based on the measured signals, a processor calculates the relative positions and orientations between source and sensor. Magnetic actuation requires a substantial amount of energy which limits the update rate with a set of batteries. Moreover, the magnetic field can easily be disturbed by ferromagnetic materials or other sources. Inertial sensors can be sampled at high rates, require only little energy and do not suffer from magnetic interferences. However, accelerometers and gyroscopes can only measure changes in position and orientation and suffer from integration drift. By combing measurements from both systems in a complementary Kalman filter structure, an optimal solution for position and orientation estimates is obtained. The magnetic system provides 6 DOF measurements at a relatively low update rate while the inertial sensors track the changes position and orientation in between the magnetic updates. The implemented system is tested against a lab-bound camera tracking system for several functional body movements. The accuracy was about 5 mm for position and 3 degrees for orientation measurements. Errors were higher during movements with high velocities due to relative movement between source and sensor within one cycle of magnetic actuation
TL;DR: In vivo results showed that increase of porosity and pore size, and thus increase of permeability of titanium alloy implants positively influenced their osteoconductive properties.
TL;DR: In this article, a framework that focuses on the concepts of the construction of identity, hierarchy and rationality to systematically analyse the various aspects of transformations of professional organizations is presented. And the main question addressed in this article is to what extent we can speak of an organizational transformation of Dutch universities.
Abstract: During the past few decades traditional state-centred governing arrangements have been critiqued and replaced by alternative modes of governance. Higher education is one of the public sectors where such shifts in governance have been seen. As a consequence of the reshuffling of authority and responsibilities across the different levels in Dutch higher education, universities as organizations have become important foci of attention in the system’s coordination. The main question addressed in this article is to what extent we can speak of an organizational transformation of Dutch universities. Based on conceptual ideas from researchers such as Greenwood and Hinings (1996), Ferlie et al. (1996), and Brunsson and Sahlin-Andersson (2000), we use a framework that focuses attention on the concepts of the construction of identity, hierarchy and rationality to systematically analyse the various aspects of transformations of professional organizations.
TL;DR: In this article, a hierarchical framework for modeling speed and accuracy on test items is presented as an alternative to these models, allowing a "plug-and-play" approach with alternative choices of models for the response and response-time distributions as well as the distributions of their parameters.
Abstract: Current modeling of response times on test items has been strongly influenced by the paradigm of experimental reaction-time research in psychology. For instance, some of the models have a parameter structure that was chosen to represent a speed-accuracy tradeoff, while others equate speed directly with response time. Also, several response-time models seem to be unclear as to the level of parametrization they represent. A hierarchical framework for modeling speed and accuracy on test items is presented as an alternative to these models. The framework allows a "plug-and-play approach" with alternative choices of models for the response and response-time distributions as well as the distributions of their parameters. Bayesian treatment of the framework with Markov chain Monte Carlo (MCMC) computation facilitates the approach. Use of the framework is illustrated for the choice of a normal-ogive response model, a lognormal model for the response times, and multivariate normal models for their parameters with Gibbs sampling from the joint posterior distribution.
TL;DR: In conclusion, irrespective of age, gender, and source of isolation, cells from all donors showed osteogenic potential, and in vitro studies suggest a correlation between in vitro ALP expression and in vivo bone formation.
TL;DR: XTT assays showed that SS-PAAs and their polyplexes possess essentially no or only very low cytotoxicity at concentrations where the highest transfection activity is observed, indicating that bioreducible poly(amido amine)s have excellent properties for the development of highly potent and nontoxic polymeric gene carriers
TL;DR: The results show that photoacoustic imaging may have potential in visualizing certain breast cancers based on intrinsic optical absorption contrast and a future role for the approach could be in supplementing conventional breast imaging to assist detection and/or diagnosis.
Abstract: Near-infrared photoacoustic images of regions-of-interest in 4 of the 5 cases of patients with symptomatic breasts reveal higher intensity regions which we attribute to vascular distribution associated with cancer. Of the 2 cases presented here, one is especially significant where benign indicators dominate in conventional radiological images, while photoacoustic images reveal vascular features suggestive of malignancy, which is corroborated by histopathology. The results show that photoacoustic imaging may have potential in visualizing certain breast cancers based on intrinsic optical absorption contrast. A future role for the approach could be in supplementing conventional breast imaging to assist detection and/or diagnosis.
TL;DR: In this paper, a comparative study of pure, SiC, and C doped MgB2 wires has revealed that the SiC doping allowed C substitution and formation to take place simultaneously at low temperatures, while the defects, small grain size, and nanoinclusions induced by C incorporation and low-temperature processing are responsible for the improvement in Jc.
Abstract: A comparative study of pure, SiC, and C doped MgB2 wires has revealed that the SiC doping allowed C substitution and MgB2 formation to take place simultaneously at low temperatures. C substitution enhances Hc2, while the defects, small grain size, and nanoinclusions induced by C incorporation and low-temperature processing are responsible for the improvement in Jc. The irreversibility field (Hirr) for the SiC doped sample reached the benchmarking value of 10 T at 20 K, exceeding that of NbTi at 4.2 K. This dual reaction model also enables us to predict desirable dopants for enhancing the performance properties of MgB2.
TL;DR: In this article, the authors assess the global water footprint of the Dutch society in relation to its coffee and tea consumption and find that Dutch people account for 2.4% of the world coffee consumption.
06 Jan 2007
TL;DR: In this article, the authors discuss how far we are from enabling computers to understand human behavior such as affecti0ve and social signaling, and propose a human-centered user interface for next generation computing.
Abstract: A widely accepted prediction is that computing will move to the background, weaving itself into the fabric of our everyday living spaces and projecting the human user into the foreground. If this prediction is to come true, then next generation computing should be about anticipatory user interfaces that should be human-centered, built for humans based on human models. They should transcend the traditional keyboard and mouse to include natural, humanlike interactive functions including understanding and emulating certain human behaviors such as affecti0ve and social signaling. This article discusses how far are we from enabling computers to understand human behavior.
TL;DR: There might not be a specific nano-ethics, but there definitely is an ethics of new & emerging science and technology (NEST), with characteristic tropes and patterns of moral argumentation as mentioned in this paper.
Abstract: There might not be a specific nano-ethics, but there definitely is an ethics of new & emerging science and technology (NEST), with characteristic tropes and patterns of moral argumentation. Ethical discussion in and around nanoscience and technology reflects such NEST-ethics. We offer an inventory of the arguments, and show patterns in their evolution, in arenas full of proponents and opponents. We also show that there are some nano-specific issues: in how size matters, and when agency is delegated to smart devices. Our overall approach is a pragmatist ethics, and we conclude that struggle (and learning) might be more productive than models emphasizing consensus.
TL;DR: In this paper, the authors present the results of a study of the influence of communication climate and perceived external prestige on organizational identification at various organizational levels of a regional police organization, and they find that perception of external prestige has a stronger influence on the identification with the organization as a whole than on the more concrete organizational levels (such as department or work group).
Abstract: sEarlier studies have shown that perceived external prestige and communication climate influence organizational identification. In this paper we present the results of a study of the influence of communication climate and perceived external prestige on organizational identification at various organizational levels of a regional police organization. In total, 314 respondents filled out a questionnaire on communication climate, perceived external prestige and organizational identification. The results of this study show that communication climate has the strongest link with employee identification when it concerns the identification with the daily work group and a weaker one with the organization as a whole. It also appears that perceived external prestige has a stronger influence on the identification with the organization as a whole than on the identification at the more concrete organizational levels (such as department or work group). This research offers reasons to presuppose that organizational identification and communication climate are multiple constructs. If management wishes to influence organizational identification through a bottom-up process, it is wise to pay particular attention to the communication climate in the work groups. Influencing organizational identification with the organization as a whole is better conducted through perceived external prestige.