Showing papers by "Katholieke Universiteit Leuven published in 1999"
TL;DR: A least squares version for support vector machine (SVM) classifiers that follows from solving a set of linear equations, instead of quadratic programming for classical SVM's.
Abstract: In this letter we discuss a least squares version for support vector machine (SVM) classifiers. Due to equality type constraints in the formulation, the solution follows from solving a set of linear equations, instead of quadratic programming for classical SVM‘s. The approach is illustrated on a two-spiral benchmark classification problem.
8,811 citations
Stanford University1, Merck & Co.2, Université libre de Bruxelles3, Yale University4, University of Salamanca5, Johns Hopkins University School of Medicine6, McGill University7, Johns Hopkins University8, University of Basel9, Université catholique de Louvain10, Thermo Fisher Scientific11, Washington University in St. Louis12, Katholieke Universiteit Leuven13
TL;DR: A total of 6925 Saccharomyces cerevisiae strains were constructed, by a high-throughput strategy, each with a precise deletion of one of 2026 ORFs (more than one-third of the ORFs in the genome), finding that 17 percent were essential for viability in rich medium.
Abstract: The functions of many open reading frames (ORFs) identified in genome-sequencing projects are unknown. New, whole-genome approaches are required to systematically determine their function. A total of 6925 Saccharomyces cerevisiae strains were constructed, by a high-throughput strategy, each with a precise deletion of one of 2026 ORFs (more than one-third of the ORFs in the genome). Of the deleted ORFs, 17 percent were essential for viability in rich medium. The phenotypes of more than 500 deletion strains were assayed in parallel. Of the deletion strains, 40 percent showed quantitative growth defects in either rich or minimal medium.
4,051 citations
TL;DR: Infliximab is an efficacious treatment for fistulas in patients with Crohn's disease and the most common adverse events for patients treated with infliximab were headache, abscess, upper respiratory tract infection, and fatigue.
Abstract: Background Enterocutaneous fistulas are a serious complication of Crohn's disease and are difficult to treat. Infliximab, a chimeric monoclonal antibody to tumor necrosis factor alpha, has recently been developed as a treatment for Crohn's disease. We conducted a randomized, multicenter, double-blind, placebo-controlled trial of infliximab for the treatment of fistulas in patients with Crohn's disease. Methods The study included 94 adult patients who had draining abdominal or perianal fistulas of at least three months' duration as a complication of Crohn's disease. Patients were randomly assigned to receive one of three treatments: placebo (31 patients), 5 mg of infliximab per kilogram of body weight (31 patients), or 10 mg of infliximab per kilogram (32 patients); all three were to be administered intravenously at weeks 0, 2, and 6. The primary end point was a reduction of 50 percent or more from base line in the number of draining fistulas observed at two or more consecutive study visits. A secondary end point was the closure of all fistulas. Results Sixty-eight percent of the patients who received 5 mg of infliximab per kilogram and 56 percent of those who received 10 mg per kilogram achieved the primary end point, as compared with 26 percent of the patients in the placebo group (P=0.002 and P=0.02, respectively). In addition, 55 percent of the patients assigned to receive 5 mg of infliximab per kilogram and 38 percent of those assigned to 10 mg per kilogram had closure of all fistulas, as compared with 13 percent of the patients assigned to placebo (P=0.001 and P=0.04, respectively). The median length of time during which the fistulas remained closed was three months. More than 60 percent of patients in all the groups had adverse events. For patients treated with infliximab, the most common were headache, abscess, upper respiratory tract infection, and fatigue. Conclusions Infliximab is an efficacious treatment for fistulas in patients with Crohn's disease.
2,516 citations
TL;DR: A consensus-based approach was applied, supplemented by input from international experts who reviewed the report, and a dyspepsia subgroup classification is proposed for research purposes, based on the predominant (most bothersome) symptom.
2,428 citations
TL;DR: In the 21st century, manufacturing companies must possess new types of manufacturing systems that are cost-effective and very responsive to all these market changes as mentioned in this paper, which are the cornerstones of this new manufacturing paradigm.
1,706 citations
TL;DR: It is found that the subscales of the FABQ and the TSK were superior in predicting self-reported disability and poor behavioral performance and the PASS appeared more strongly associated with pain catastrophizing and negative affect, and was less predictive of pain disability and behavioral performance.
Abstract: There is growing evidence for the idea that in back pain patients, pain-related fear (fear of pain/physical activity/(re)injury) may be more disabling than pain itself. A number of questionnaires have been developed to quantify pain-related fears, including the Fear-Avoidance Beliefs Questionnaire (FABQ), the Tampa Scale for Kinesiophobia (TSK), and the Pain Anxiety Symptoms Scale (PASS). A total of 104 patients, presenting to a rehabilitation center or a comprehensive pain clinic with chronic low back pain were studied in three independent studies aimed at (1) replicating that pain-related fear is more disabling than pain itself (2) investigating the association between pain-related fear and poor behavioral performance and (3) investigating whether pain-related fear measures are better predictors of disability and behavioral performance than measures of general negative affect or general negative pain beliefs (e.g. pain catastrophizing). All three studies showed similar results. Highest correlations were found among the pain-related fear measures and measures of self-reported disability and behavioral performance. Even when controlling for sociodemographics, multiple regression analyses revealed that the subscales of the FABQ and the TSK were superior in predicting self-reported disability and poor behavioral performance. The PASS appeared more strongly associated with pain catastrophizing and negative affect, and was less predictive of pain disability and behavioral performance. Implications for chronic back pain assessment, prevention and treatment are discussed.
1,585 citations
TL;DR: Based on the direct 3D analysis of human bone biopsies, it appears that samples with a lower bone mass are primarily characterized by a smaller plate‐to‐rod ratio, and to a lesser extent by thinner trabecular elements.
Abstract: The appearance of cancellous bone architecture is different for various skeletal sites and various disease states. During aging and disease, plates are perforated and connecting rods are dissolved. There is a continuous shift from one structural type to the other. So traditional histomorphometric procedures, which are based on a fixed model type, will lead to questionable results. The introduction of three-dimensional (3D) measuring techniques in bone research makes it possible to capture the actual architecture of cancellous bone without assumptions of the structure type. This requires, however, new methods that make direct use of the 3D information. Within the framework of a BIOMED I project of the European Union, we analyzed a total of 260 human bone biopsies taken from five different skeletal sites (femoral head, vertebral bodies L2 and L4, iliac crest, and calcaneus) from 52 donors. The samples were measured three-dimensionally with a microcomputed tomography scanner and subsequently evaluated with both traditional indirect histomorphometric methods and newly developed direct ones. The results show significant differences between the methods and in their relation to the bone volume fraction. Based on the direct 3D analysis of human bone biopsies, it appears that samples with a lower bone mass are primarily characterized by a smaller plate-to-rod ratio, and to a lesser extent by thinner trabecular elements.
1,326 citations
TL;DR: Targeted inactivation or truncation of the beta-catenin-binding cytosolic domain of the VE-cadherin gene was found to affect assembly of endothelial cells in vascular plexi, but to impair their subsequent remodeling and maturation, causing lethality at 9.5 days of gestation.
1,320 citations
TL;DR: In this paper, a novel approach of stochastic subspace identification is presented that incorporates the idea of the reference sensors already in the identification step: the row space of future outputs is projected into the rowspace of past reference outputs.
1,236 citations
TL;DR: In this article, the authors examine antecedents of consumer innovativeness in a cross-national context and propose a framework that distinguishes individual difference variables and national cultural variables to distinguish consumer difference variables.
Abstract: The authors examine antecedents of consumer innovativeness in a cross-national context. They propose a framework that distinguishes individual difference variables and national cultural variables. ...
1,166 citations
TL;DR: In this article, a review of literature based on the analysis of 63 studies suggests that the use of a combination of different new assessment forms encourages students to become more responsible and reflective.
Abstract: The growing demand for lifelong learners and reflective practitioners has stimulated a re-evaluation of the relationship between learning and its assessment, and has influenced to a large extent the development of new assessment forms such as self-, peer, and co-assessment. Three questions are discussed: (1) what are the main findings from research on new assessment forms such as self-, peer and co-assessment; (2) in what way can the results be brought together; and (3) what guidelines for educational practitioners can be derived from this body of knowledge? A review of literature, based on the analysis of 63 studies, suggests that the use of a combination of different new assessment forms encourages students to become more responsible and reflective. The article concludes with some guidelines for practitioners.
TL;DR: The algorithm is able to segment single- and multi-spectral MR images, corrects for MR signal inhomogeneities, and incorporates contextual information by means of Markov random Fields (MRF's).
Abstract: Describes a fully automated method for model-based tissue classification of magnetic resonance (MR) images of the brain. The method interleaves classification with estimation of the model parameters, improving the classification at each iteration. The algorithm is able to segment single- and multi-spectral MR images, corrects for MR signal inhomogeneities, and incorporates contextual information by means of Markov random Fields (MRF's). A digital brain atlas containing prior expectations about the spatial location of tissue classes is used to initialize the algorithm. This makes the method fully automated and therefore it provides objective and reproducible segmentations. The authors have validated the technique on simulated as well as on real MR images of the brain.
TL;DR: In this article, the impact of job insecurity on workers differ according to their professional position, gender, and age, and how important is job insecurity compared to other stressors on the workfloor.
Abstract: Research on the psychological consequences of job insecurity is reviewed, showing that job insecurity reduces psychological well-being and job satisfaction, and increases psychosomatic complaints and physical strains. Next, three additional research questions are addressed, since these questions did not receive much attention in previous research. First, does the impact of job insecurity on workers differ according to their professional position, gender, and age? Second, how important is job insecurity compared to other stressors on the workfloor? Third, how important is job insecurity compared to the impact of unemployment? To analyse these issues, data were used from a Belgian plant, part of a European multinational company in the metalworking industry (N = 336). The results of this exploratory study showed that job insecurity was associated with lower well-being (score on the GHQ-12), after controlling for background variables, such as gender and age. A significant interaction with gender occurred, ind...
TL;DR: Long-term treatment with infliximab showed efficacy and tolerability in managing symptoms of patients with active Crohn's disease not responding to conventional treatments.
TL;DR: In this article, the authors examine the relation between the innovation strategy and industry-, firm and innovation-specific characteristics using Belgian company data from the Eurostat Community Innovation Survey (CIS).
TL;DR: It is concluded that the six minute walking distance can be predicted adequately using a clinically useful model in healthy elderly subjects and its variability is explained largely by age, sex, height and weight.
Abstract: The six minute walking distance (6MWD) test is a commonly used test to estimate functional exercise capacity in patients with chronic diseases including chronic obstructive lung disease. Surprisingly, no attempt has been made to establish normal values for the 6MWD. The aim of this study, therefore, was to evaluate the 6MWD in healthy elderly volunteers and to evaluate its determining factors. Fifty-one healthy subjects aged 50-85 yrs volunteered to participate in the trial. All subjects were free of diseases that could interfere with performance in a walking test. Tests were performed in a quiet 50-m long hospital corridor. Patients were encouraged every 30 s to continue walking as quickly as possible. Walking distance averaged 631+/-93 m and was 84 m greater in the male compared to female subjects (p<0.001). The 6MWD showed significant correlations with age (r=-0.51, p<0.01) and height (r=0.54, p<0.01). Stepwise multiple regression analysis showed that age, height, sex and weight were independent contributors to the 6MWD in healthy subjects, thus explaining 66% of the variability. It is concluded that the six minute walking distance can be predicted adequately using a clinically useful model in healthy elderly subjects. Its variability is explained largely by age, sex, height and weight. Results of the six minute walking distance may be interpreted more adequately if expressed as a percentage of the predicted value.
TL;DR: This report summarises conclusions from an evidence-based workshop which evaluated major clinical strategies for the management of the full spectrum of gastro-oesophageal reflux disease, with an emphasis on medical management.
Abstract: This report summarises conclusions from an evidence-based workshop which evaluated major clinical strategies for the management of the full spectrum of gastro-oesophageal reflux disease, with an emphasis on medical management.
The disease was defined by the presence of oesophageal mucosal breaks or by the occurrence of reflux induced symptoms severe enough to impair quality of life. Endoscopy negative patients were recognised as the most common subgroup; most of these patients can be diagnosed by a well structured symptom analysis. There is a consistent hierarchy of effectiveness of available initial and long term therapies that applies for all patient subgroups. Lifestyle measures were judged to be of such low efficacy that they were rejected as a primary therapy for all patient subgroups. Proton pump inhibitor therapy was considered the initial medical treatment of choice because of its clearly superior efficacy which results in the most prompt achievement of desirable outcomes at the lowest overall medical cost. It was acknowledged that most of patients require long term management and that any maintenance therapy should be chosen by step down to the regimen that is still effective, but least costly. Endoscopic monitoring of routine long term therapy was considered inappropriate, on the basis that control of symptoms is an acceptably reliable indicator of healing in patients with oesophagitis.
Laparoscopic antireflux surgery was recognised as a significant therapeutic advance, the results of which, however, depend substantially on the experience of the surgeon. There are currently no published direct comparisons of cost and efficacy outcomes of optimal medical and surgical therapies for reflux disease. To a significant degree, the choice between medical and surgical therapy should depend on informed patient preference.
Substantial advances have occurred recently in the understanding and treatment of reflux disease. By contrast, there has been relatively little research into the best …
TL;DR: A theoretical proof is given which shows that the absence of skew in the image plane is sufficient to allow for self-calibration and a method to detect critical motion sequences is proposed.
Abstract: In this paper the theoretical and practical feasibility of self-calibration in the presence of varying intrinsic camera parameters is under investigation. The paper‘s main contribution is to propose a self-calibration method which efficiently deals with all kinds of constraints on the intrinsic camera parameters. Within this framework a practical method is proposed which can retrieve metric reconstruction from image sequences obtained with uncalibrated zooming/focusing cameras. The feasibility of the approach is illustrated on real and synthetic examples. Besides this a theoretical proof is given which shows that the absence of skew in the image plane is sufficient to allow for self-calibration. A counting argument is developed which—depending on the set of constraints—gives the minimum sequence length for self-calibration and a method to detect critical motion sequences is proposed.
15 Dec 1999-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the authors stress the need for further exploration of the 4P-relation: principles-properties-processing-products as well as in companies as well in universities or other research laboratories, illustrated by describing some actual applications indicating why they are successful, other applications why they failed and still others that can only be realised if some further, probably possible, material improvement can be realised.
Abstract: The diversity of (potential) applications using shape memory alloys (SMA), apart from the medical field, becomes quite large. Classic categories such as free recovery, actuators, constrained recovery, pseudo-elasticity or damping require further specifications. For example, micro-actuators, smart materials or active damping, can be all classified as actuator applications, but each of those items demands specific functional performance, dimensions and processing. Furthermore, success for applications can only be realised in so far those materials offer also a price-competitive advantage relative to other functional materials or mechanical designs. This competition requires perfect control of the material performance. It is known that especially Ni–Ti alloys can be tuned relatively easy to some specific requirements of the envisaged application: hysteresis, transformation temperatures, damping capacity. At the other side little is known on recovery stresses, wear resistance, fracture mechanics, fatigue … In this paper we would like to stress the need for further exploration of the 4P-relation: principles–properties–processing–products as well in companies as in universities or other research laboratories. This will be illustrated by describing some actual applications indicating why they are successful, other applications why they failed and still others that can only be realised if some further, probably possible, material improvement can be realised.
TL;DR: Temporary administration of PA inhibitor-1 or the matrix metalloproteinase-inhibitor TIMP-1 completely protected wild-type mice against rupture but did not abort infarct healing, thus constituting a new approach to prevent cardiac rupture after acute myocardial infarction.
Abstract: Cardiac rupture is a fatal complication of acute myocardial infarction lacking treatment. Here, acute myocardial infarction resulted in rupture in wild-type mice and in mice lacking tissue-type plasminogen activator, urokinase receptor, matrix metalloproteinase stromelysin-1 or metalloelastase. Instead, deficiency of urokinase-type plasminogen activator (u-PA–/–) completely protected against rupture, whereas lack of gelatinase-B partially protected against rupture. However, u-PA–/– mice showed impaired scar formation and infarct revascularization, even after treatment with vascular endothelial growth factor, and died of cardiac failure due to depressed contractility, arrhythmias and ischemia. Temporary administration of PA inhibitor-1 or the matrix metalloproteinase-inhibitor TIMP-1 completely protected wild-type mice against rupture but did not abort infarct healing, thus constituting a new approach to prevent cardiac rupture after acute myocardial infarction.
TL;DR: In this article, the retention of a series of organic molecules by four nanofiltration membranes was studied, and a good correlation with retention was found for each of the size parameters: molecular weight, the Stokes diameter, the equivalent molar diameter and a diameter obtained with energy minimisation calculations.
TL;DR: Chronic electrical stimulation instead of bilateral capsulotomy was done in four selected patients with long-standing treatment-resistant obsessive-compulsive disorder and beneficial effects were observed.
TL;DR: Cognitive deficits and phenotypic traits early in life that dissociated in time from the formation of amyloid plaques will be good models for both early and late neuropathological and clinical aspects of Alzheimer’s disease.
TL;DR: Clinical improvement after infliximab therapy in active Crohn's disease is accompanied by significant healing of endoscopic lesions and disappearance of the mucosal inflammatory infiltrate and architectural changes persisted in most patients.
TL;DR: Tenecteplase and alteplase were equivalent for 30-day mortality and the ease of administration of tenectePLase may facilitate more rapid treatment in and out of hospital.
TL;DR: Impaired myocardial angiogenesis and ischemic cardiomyopathy in mice lacking the vascular endothelial growth factor isoforms V EGF 164 and VEGF 188 is observed.
Abstract: Impaired myocardial angiogenesis and ischemic cardiomyopathy in mice
lacking the vascular endothelial growth factor isoforms VEGF 164
and VEGF 188
TL;DR: Analysis of the p63 gene, a homolog of p53 located in the critical LMS/EEC interval, revealed heterozygous mutations in nine unrelated EEC families that provide a molecular explanation for the dominant character of p63 mutations in EEC syndrome.
TL;DR: The aim of this review is to provide basic information on the electrophysiological changes during acute ischemia and reperfusion from the level of ion channels up to thelevel of multicellular preparations.
Abstract: The aim of this review is to provide basic information on the electrophysiological changes during acute ischemia and reperfusion from the level of ion channels up to the level of multicellular prep...
TL;DR: A major issue that remains to be resolved is the precise connection between the cAMP–PKA pathway and other nutrient‐regulated components involved in the control of growth and of phenotypic characteristics correlated with growth, such as the Sch9 and Yak1 protein kinases.
Abstract: The cAMP-protein kinase A (PKA) pathway in the yeast Saccharomyces cerevisiae plays a major role in the control of metabolism, stress resistance and proliferation, in particular in connection with the available nutrient conditions. Extensive information has been obtained on the core section of the pathway, i.e. Cdc25, Ras, adenylate cyclase, PKA, and on components interacting directly with this core section, such as the Ira proteins, Cap/Srv2 and the two cAMP phosphodiesterases. Recent work has now started to reveal upstream regulatory components and downstream targets of the pathway. A G-protein-coupled receptor system (Gpr1-Gpa2) acts upstream of adenylate cyclase and is required for glucose activation of cAMP synthesis in concert with a glucose phosphorylation-dependent mechanism. Although a genuine signalling role for the Ras proteins remains unclear, they appear to mediate at least part of the potent stimulation of cAMP synthesis by intracellular acidification. Recently, several new targets of the PKA pathway have been discovered. These include the Msn2 and Msn4 transcription factors mediating part of the induction of STRE-controlled genes by a variety of stress conditions, the Rim15 protein kinase involved in stationary phase induction of a similar set of genes and the Pde1 low-affinity cAMP phosphodiesterase, which specifically controls agonist-induced cAMP signalling. A major issue that remains to be resolved is the precise connection between the cAMP-PKA pathway and other nutrient-regulated components involved in the control of growth and of phenotypic characteristics correlated with growth, such as the Sch9 and Yak1 protein kinases. Cln3 appears to play a crucial role in the connection between the availability of certain nutrients and Cdc28 kinase activity, but it remains to be clarified which nutrient-controlled pathways control Cln3 levels.
TL;DR: In this article, the authors investigated the cohort of a randomized trial of thrombolysis to assess the early and late clinical course associated with different subtypes of hemorrhagic infarction (HI) and parenchymal hematoma (PH) detected within the first 36 hours of an ischemic stroke.
Abstract: Background and Purpose—The clinical correlates of the varying degrees of early hemorrhagic transformation of a cerebral infarct are unclear. We investigated the cohort of a randomized trial of thrombolysis to assess the early and late clinical course associated with different subtypes of hemorrhagic infarction (HI) and parenchymal hematoma (PH) detected within the first 36 hours of an ischemic stroke. Methods—We exploited the database of the European Cooperative Acute Stroke Study I (ECASS I), a randomized, placebo-controlled, phase III trial of intravenous recombinant tissue plasminogen activator in acute ischemic stroke. Findings on 24- to 36- hour CT were classified into 5 categories: no hemorrhagic transformation, HI types 1 and 2, and PH types 1 and 2. We assessed the risk of concomitant neurological deterioration and of 3-month death and disability associated with subtypes of hemorrhagic transformation, as opposed to no bleeding. Risks were adjusted for age and extent of ischemic damage on baseline ...