Ghent University is a highly ranked Dutch-speaking public university located in Ghent, Belgium. It is one of the larger Flemish universities, consisting of 41,000 students and 9,000 staff members. The current rector is Anne De Paepe . As of 2014, Ghent University ranks as 90th globally according to Times Higher Education, 129th according to QS World University Rankings and 70th according to the Academic Ranking of World Universities. It is therefore considered to be a top university, globally.It was established in 1817 by King William I of the Netherlands. After the Belgian revolution of 1830, it was administered by the newly formed Belgian state. French became the academic language until 1930, when Ghent University became the first Dutch-speaking university in Belgium. In 1991, the university was granted major autonomy and changed its name from State University of Ghent to its current name. Wikipedia.
Van Reeth K.,Ghent University
Current topics in microbiology and immunology | Year: 2013
Commercial vaccines currently available against swine influenza virus (SIV) are inactivated, adjuvanted, whole virus vaccines, based on H1N1 and/or H3N2 and/or H1N2 SIVs. In keeping with the antigenic and genetic differences between SIVs circulating in Europe and the US, the vaccines for each region are produced locally and contain different strains. Even within a continent, there is no standardization of vaccine strains, and the antigen mass and adjuvants can also differ between different commercial products. Recombinant protein vaccines against SIV, vector, and DNA vaccines, and vaccines attenuated by reverse genetics have been tested in experimental studies, but they have not yet reached the market. In this review, we aim to present a critical analysis of the performance of commercial inactivated and novel generation SIV vaccines in experimental vaccination challenge studies in pigs. We pay special attention to the differences between commercial SIV vaccines and vaccination attitudes in Europe and in North America, to the issue of vaccine strain selection and changes, and to the potential advantages of novel generation vaccines over the traditional killed SIV vaccines.
Ionescu C.M.,Ghent University
IEEE Transactions on Systems, Man, and Cybernetics Part A:Systems and Humans | Year: 2012
This paper presents a novel concept of modeling biological systems by means of preserving the natural rules governing the system's dynamics, i.e., their intrinsic fractal (recurrent) structure. The purpose of this paper is to illustrate the capability of recurrent ladder networks to capture the intrinsic recurrent anatomy of neural networks and to provide a dynamic model which shows typical neuronal phenomena, such as the phase constancy. As an illustrating example, the simplified model for a neural network consisting of motor neurons is used in simulation of a recurrent ladder network. Starting from a generalized approach, it is shown that, in the steady state, the result converges to a constant-phase behavior. The outcome of this paper indicates that the proposed model is a suitable tool for specific neural models in various neuroscience applications, being able to capture their fractal structure and the corresponding fractal dynamic behavior. A link to the dynamics of EEG activity is suggested. By studying specific neural populations by means of the ladder network model presented in this paper, one might be able to understand the changes observed in the EEG with normal aging or with neurodegenerative disorders. © 2012 IEEE.
Pennings G.,Ghent University
Human Reproduction | Year: 2012
Victoria (Australia) is considering retrospective legislation on the abolition of gamete donor anonymity. Retrospective legislation evokes many negative emotions mainly because it is considered unfair. It also makes it impossible for citizens to organize their life with reasonable certainty of the consequences. Introduction of this law for donor anonymity is defended by the right of the child to know its genetic origins. Against this law, people appeal to the right to privacy and confidentiality of the donor. This paper analyses the arguments for and against a retrospective law on donor anonymity by looking at the conditions that should be respected when two principles (the donor's right to privacy and the child's right to genetic information) have to be balanced. It is concluded that the justification for introducing retrospective law is lacking: the conditions are not fulfilled. Moreover, retroactive laws in the context of gamete donation may jeopardize the whole practice by destroying the trust of candidate donors and recipients in the government. © 2012 The Author.
Derveaux T.,Ghent University
Retina | Year: 2016
PURPOSE:: To describe the structural and functional characteristics of oxalate retinopathy. METHODS:: Five patients with molecularly confirmed primary hyperoxaluria (PH) Type 1 underwent multimodal retinal imaging (spectral-domain optical coherence tomography, white light, and HRA multispectral imaging) and functional testing, including color vision testing, Goldmann perimetry, and International Society for Clinical Electrophysiology of Vision standard electrophysiological testing. RESULTS:: Four distinct retinal phenotypes are presented. One patient with a c.[33dupC]; c.[731T>C] mutation showed bilateral perifoveal retinal pigment epithelium hyperplasia. The fundus in the four other patients, all of whom share an identical homozygous c.[33dupC] mutation, ranged from normal to bilateral widespread distribution of retinal crystals and confluent macular retinal pigment epithelium hyperplasia with subfoveal fibrosis. All patients who had developed end-stage renal disease showed some sign of retinopathy, more severe with earlier onset. CONCLUSION:: Retinopathy in PH Type 1 shows considerable interindividual variation. No correlation between genotype and retinal phenotype was detected. Oxalate crystals at the level of the retinal pigment epithelium seem to be irreversible. A proposed clinical grading system of oxalate maculopathy, based on a literature review, may provide clinicians with a tool to better predict visual function and prognosis. © 2016 by Ophthalmic Communications Society, Inc.
Flexer V.,CNRS Paul Pascal Research Center |
Flexer V.,Ghent University |
Mano N.,CNRS Paul Pascal Research Center
Analytical Chemistry | Year: 2014
We report unprecedented high current densities for the enzymatic oxidation of glucose already at 0 V versus Ag/AgCl. The modified electrodes were made by assembling pyrroloquinoline quinone (PQQ)-soluble glucose dehydrogenase (PQQ-sGDH) from Acinetobacter calcoaceticus with osmium-based redox polymers and a cross-linker. Both redox mediators are made of a poly(4-vinylpyridine) (PVP) polymer with Os complexes tethered to the polymer backbone via long C chains, giving the Os complexes flexibility and mobility inside the redox hydrogels. Current densities larger than 1 mA cm-2 were measured already below 0 V with a plateau value of 4.4 mA cm-2. Similar hydrogel electrodes comprising the same redox polymers and glucose oxidase (GOx) showed less than half the current densities of the PQQ-sGDH electrodes. The current versus potential curve dependence showed a sigmoidal shape characteristic of mediated enzyme catalysis but with a current increase versus potential less sharp than expected. Surprisingly, the midwave redox potential was positively shifted with respect to the potential of the redox mediator. © 2014 American Chemical Society.
Verhelst S.,Ghent University
International Journal of Hydrogen Energy | Year: 2014
Hydrogen-fueled internal combustion engines (H2ICEs) have been the topic of research for many decades, and contemporary reviews have surveyed the relevant literature. Because of a number of relatively large R&D projects that have been ongoing recently, much progress has been made that is worth reporting. Specifically, this paper reviews the advancements made in plotting the possibilities offered by direct injection of hydrogen, in-cylinder heat transfer, modeling and combustion strategies (on an engine as well as vehicle level). These efforts have resulted in impressive efficiency numbers, both at peak and part load operation, while keeping emissions far below regulatory limits and reaching satisfactory specific power outputs. New demonstration vehicles have been put on the road showing the relatively low barriers (on a vehicle level) to introduce hydrogen engined transportation and these are briefly described. The paper discusses the merits of H2ICEs but also what makes them potentially unfit as a realistic alternative. Finally, the paper concludes with the main areas of research that require further efforts. Copyright © 2013, Hydrogen Energy Publications, LLC.
Dubuy V.,Ghent University
Health education research | Year: 2013
The aim of the study was to evaluate the impact of the state-wide dissemination of a physical activity (PA) intervention in Flanders. In 2011, a random sample was taken of the entire adult (25-75 years) population of Flanders. Data of the Flemish sample were compared with baseline data of the intervention and control group of '10 000 Steps Ghent' (2005). In total, data of the International Physical Activity Questionnaire were available of 2556 respondents (1675 of the comparison sample and 881 of the Flemish sample). Pedometer data were obtained by 269 respondents of the Flemish sample and by 1236 respondents of the comparison sample. Compared with the comparison sample of 2005, the Flemish sample reported more walking (P < 0.001), moderate (P < 0.001), vigorous (P < 0.001), work-related (P < 0.001), leisure time (P = 0.01) and household PA (P = 0.03). Step count analyses revealed that the Flemish sample took more pedometer-based daily step counts (P < 0.001) than the comparison sample. Furthermore, a higher proportion of respondents reaching the 10 000 steps/day goal (P = 0.005) was found in the Flemish sample. A positive effect of '10 000 Steps Flanders' was found. Results indicate that a state-wide approach based on socio-ecological models is an effective strategy to promote PA in a large population.
Vanheule S.,Ghent University
Psychology and Psychotherapy: Theory, Research and Practice | Year: 2012
Purpose. This paper studies how diagnosis is currently conceptualized in the field of psychiatry, and examines whether this mode of diagnosis is relevant for psychotherapeutic intervention. Method. Narrative literature review was used in this study. Results. In the context of the DSM, diagnosis is equated with classification. Symptoms and complaints are approached in terms of a medical semiological model, and are seen as signs of underlying illness processes. In discussing this approach the author makes use of Gottlob Frege's theory, in which three aspects of a sign are discerned: the reference/referent or Bedeutung, the sense or Sinn, and the representation/idea or Vorstellung. Based on this distinction, it is argued that in the transition from the DSM-III to the DSM-5 much effort has been taken to disambiguate the sense attributed to symptoms and complaints, while person-specific ideas and representations have been excluded. This exclusion of the Vorstellung is criticized, both from a psychiatric and a psychotherapeutic perspective. Subsequently it is argued that whereas the DSM-III and DSM-IV avoided strong statements on etiology, the DSM-5 makes clear choices. The DSM-5, and more recently the RDoC group within the NIMH, aims at developing systems of classification that start from the assumption that psychiatric disorders are brain disorders. It is argued that by doing so a referent is classified that is different from the object of intervention that psychotherapeutic theories are concerned with. Conclusion. Such a view of diagnosis is not workable for psychotherapy. The exclusion of personal experiences associated with symptoms and complaints is problematic and the referent that recent psychiatric classification uses, that is, brain processes, is not compatible with the referent that psychotherapeutic theories use. Case formulation can be seen as an alternative to standard classification. Practitioner Points A clear distinction between classification and diagnosis should be made. Psychotherapeutic diagnosis cannot exclude information on the embedding of problems in broader life contexts. Case formulation is a viable alternative to classification. © 2012 The British Psychological Society.
De Frenne P.,Ghent University
New Phytologist | Year: 2015
The prediction of the effects of climate warming on plant communities across the globe has become a major focus of ecology, evolution and biodiversity conservation. However, many of the frequently used empirical approaches for inferring how warming affects vegetation have been criticized for decades. In addition, methods that require no electricity may be preferred because of constraints of active warming, e.g. in remote areas. Efforts to overcome the limitations of earlier methods are currently under development, but these approaches have yet to be systematically evaluated side by side. Here, an overview of the benefits and limitations of a selection of innovative empirical techniques to study temperature effects on plants is presented, with a focus on practicality in relatively remote areas without an electric power supply. I focus on methods for: ecosystem aboveground and belowground warming; a fuller exploitation of spatial temperature variation; and long-term monitoring of plant ecological and microevolutionary changes in response to warming. An evaluation of the described methodological set-ups in a synthetic framework along six axes (associated with the consistency of temperature differences, disturbance, costs, confounding factors, spatial scale and versatility) highlights their potential usefulness and power. Hence, further developments of new approaches to empirically assess warming effects on plants can critically stimulate progress in climate-change biology. © 2014 New Phytologist Trust.
Wauman J.,Vlaams Institute for Biotechnology |
Tavernier J.,Ghent University
Frontiers in Bioscience | Year: 2011
The identification of spontaneous mutations in the leptinand leptin receptor (ObR)-encoding ob and db gene, respectively, opened up a new field in obesity research. Leptin, an adipocyte-derived hormone, mirrors the body's fat stores and thereby informs the brain about the body's energy status. In the hypothalamus, leptin triggers specific neuronal subpopulations, like POMC and AgRP/NPY neurons, and activates several intracellular signaling events, including the JAK/STAT, MAPK, PI3K and mTOR pathway, which eventually translates into decreased food intake and increased energy expenditure. Leptin is also involved in the regulation of other physiological processes including reproduction, bone homeostasis and immune function. Here, we review the pathways that are activated upon ObR activation, how ObR expression is controlled and the molecular mechanisms leading to leptin resistance, i.e. the inability to adequately respond to elevated leptin levels and therefore a primary risk factor for obesity.
Vandijck D.M.,Ghent University
Nursing in critical care | Year: 2010
Changes in patient profile, and in the health care environment, altering socioeconomic conditions and advances in science and information technology challenge the nursing profession, in particular intensive care nursing. All these changes will undoubtedly affect the way we will practice in the (near) future. A comprehensive understanding of these factors is therefore essential if nursing is to meet the challenges presented by tomorrow's critical care environment. Precisely because of the often expensive high-tech evolutions that have occurred at a rapid pace and are to be further expected, a continued focus on the basics of nursing, the core role of care, as well as maintaining confidence in the capacity to deliver safe, high-quality, and evidence-based patient care will increasingly be a challenge to critical care nurses. In particular, basic nursing skills and knowledge remain a key prerequisite in the prevention of nosocomial infections, which is a continuing major complication and threat to intensive care unit patients. However, critical care nurses' knowledge about the evidence-based consensus recommendations for infection prevention and control has been found to be rather poor. It has nevertheless been demonstrated that a meticulous implementation of such preventive bundles may result in significantly better patient and process outcomes. Moreover, many preventive strategies are considered to be easy to implement and inexpensive. As such, a first and critical step should be to increase critical care nurses' adherence to the recommendations of the Centers for Disease Control and Prevention. In this article, an up-to-date assessment of evidence-based recommendations for the prevention of nosocomial infections, with special focus on catheter-related bloodstream infections and strategies relevant for nurses working in critical care environments, will be provided. Additionally, we will detail on a number of approaches advocated to translate the internationally accepted consensus recommendations to the needs and expectations of critical care nurses, and to consequently enhance the likelihood of successful implementation and adherence. These steps will help critical care nurses in their striving towards excellence in their profession. Intensive care nurses can make a significant contribution in preventing nosocomial infections by assuming full responsibility for quality improvement measures such as evidence-based infection prevention and control protocols. However, as general knowledge of the preventive measures has been shown to be rather poor, nurses' education should include supplementary support from evidence-based recommendations.
Tourchi A.,Brady Urological Institute |
Hoebeke P.,Ghent University
Journal of Pediatric Urology | Year: 2013
Hypospadias, epispadias with or without exstrophy, and disorders of sex development are among the most common anomalies of genitalia that occur during childhood. Considering the tremendous effect of genitourinary reconstruction on adult life, the evaluation of the long-term results of different techniques of genitoplasty in pediatrics is of the utmost importance. After reviewing the literature, the authors summarize the available long-term outcomes of genitoplasty in childhood, specifically focusing on the cosmetic, psychosocial, psychosexual and functional results, and emphasize that, contrary to the widely available data on early outcomes of genital reconstruction in the pediatric population, very few well described controlled studies have evaluated the long-term effect of genitoplasty in puberty and adulthood, in the sense that the surgeon should describe the peroperative findings in more detail and also be more structured in evaluating the postoperative result at follow-up visits. Finally, the authors conclude that more attention should be paid to the impact of these techniques on cosmetic aspects and psychosexual development in these patients after puberty, as they play a crucial role in their adult quality of life.
Su Y.,TU Eindhoven |
Straathof N.J.W.,TU Eindhoven |
Hessel V.,TU Eindhoven |
Noel T.,TU Eindhoven |
Noel T.,Ghent University
Chemistry - A European Journal | Year: 2014
Continuous-flow photochemistry is used increasingly by researchers in academia and industry to facilitate photochemical processes and their subsequent scale-up. However, without detailed knowledge concerning the engineering aspects of photochemistry, it can be quite challenging to develop a suitable photochemical microreactor for a given reaction. In this review, we provide an up-to-date overview of both technological and chemical aspects associated with photochemical processes in microreactors. Important design considerations, such as light sources, material selection, and solvent constraints are discussed. In addition, a detailed description of photon and mass-transfer phenomena in microreactors is made and fundamental principles are deduced for making a judicious choice for a suitable photomicroreactor. The advantages of microreactor technology for photochemistry are described for UV and visible-light driven photochemical processes and are compared with their batch counterparts. In addition, different scale-up strategies and limitations of continuous-flow microreactors are discussed. Light up your chemistry! Continuous-flow photochemistry is used increasingly by researchers in academia and industry to facilitate photochemical processes and their subsequent scale-up. This Review provides an up-to-date overview of both technological and chemical aspects associated with photochemical processes in microreactors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Vandenabeele P.,Ghent University |
Edwards H.G.M.,University of Bradford |
Jehlicka J.,Charles University
Chemical Society Reviews | Year: 2014
The applications of analytical Raman spectroscopy in the characterisation of materials associated with archaeologically excavated artefacts, forensic investigations of drugs of abuse, security and crime scenes, minerals and rocks and future astrobiological space missions are now well established; however, these applications have emphasised the need for new developments in the area of miniaturised instrumentation which extends the concept and breadth of the analytical requirement to facilitate the provision of data from 'in field' studies. In this respect, the apparently unrelated themes of art and archaeology, forensic science, geological science and astrobiology as covered by this review are unified broadly by the ability to record data nondestructively and without resorting to sampling and the subsequent transfer of samples to the analytical laboratory. In studies of works of art there has long been a requirement for on-site analysis, especially for valuable paintings held under strict museum security and for wall paintings which cannot physically be removed from their setting; similarly, the use of portable Raman spectroscopy in archaeological and geological field work as a first-pass screening device which obviates the necessity of multiple and wasteful specimen collection is high on the wish-list of practicing spectroscopists. As a first-pass screening probe for forensic crime scenes, Raman spectroscopy has proved to be of inestimable value for the early detection of dangerous and prohibited materials such as drugs of abuse, explosives and their chemical precursors, and banned contraband biomaterials such as ivories and animal products; in these applications the advantage of the Raman spectroscopic technique for the recognition of spectral signatures from mixtures of inorganic and organic compounds is paramount and not afforded by other less portable instrumental techniques. Finally, in astrobiological work, these requirements also apply but with the additional prerequisite for system operation remotely-often over distances of several hundred million kilometres-as part of instrumental suites on robotic spacecraft and planetary landers; this necessitates robust and reliable instrumentation for the observation of unique and characteristic spectral features from the planetary geological surface and subsurface which are dependent on the assignment of both biological and geological band signatures. This journal is © the Partner Organisations 2014.
Richter M.,Ghent University
BMC public health | Year: 2012
Important unanswered questions remain on the impact of international sporting events on the sex industry. Speculation about increased demand and supply of sex work often generates significant attention, but also additional funding for HIV programmes. This study assessed whether changes occurred in the demand and supply of paid sex during the 2010 Soccer World Cup in South Africa. Trained sex worker interviewers conducted face-to-face semi-structured interviews among consenting female sex workers during May-September 2010. Using bivariate analyses we compared supply, demand, sexual risk-taking, and police and health services contact pre-World Cup, to levels during the World Cup and after the event. No increases were detected in indicators of sex work supply, including the proportion of sex workers newly arrived in the city (< 2.5% in each phase) or those recently entering the trade (≤ 1.5%). Similarly, demand for sex work, indicated by median number of clients (around 12 per week) and amount charged per transaction ($13) remained similar in the three study periods. Only a third of participants reported observing any change in the sex industry ascribed to the World Cup. Self-reported condom-use with clients remained high across all samples (> 92.4% in all phases). Health-care utilisation decreased non-significantly from the pre- to during World Cup period (62.4% to 57.0%; P = 0.075). Across all periods, about thirty percent of participants had interacted with police in the preceding month, two thirds of whom had negative interactions. Contrary to public opinion, no major increases were detected in the demand or supply of paid sex during the World Cup. Although the study design employed was unable to select population-based samples, these findings do not support the public concern and media speculation prior to the event, but rather signal a missed opportunity for public health action. Given the media attention on sex work, future sporting events offer strategic opportunities to implement services for sex workers and their clients, especially as health service utilisation might decrease in this period.
Vansteelandt S.,Ghent University |
Daniel R.M.,London School of Hygiene and Tropical Medicine
Statistics in Medicine | Year: 2014
Propensity scores are widely adopted in observational research because they enable adjustment for high-dimensional confounders without requiring models for their association with the outcome of interest. The results of statistical analyses based on stratification, matching or inverse weighting by the propensity score are therefore less susceptible to model extrapolation than those based solely on outcome regression models. This is attractive because extrapolation in outcome regression models may be alarming, yet difficult to diagnose, when the exposed and unexposed individuals have very different covariate distributions.Standard regression adjustment for the propensity score forms an alternative to the aforementioned propensity score methods, but the benefits of this are less clear because it still involves modelling the outcome in addition to the propensity score. In this article, we develop novel insights into the properties of this adjustment method. We demonstrate that standard tests of the null hypothesis of no exposure effect (based on robust variance estimators), as well as particular standardised effects obtained from such adjusted regression models, are robust against misspecification of the outcome model when a propensity score model is correctly specified; they are thus not vulnerable to the aforementioned problem of extrapolation. We moreover propose efficient estimators for these standardised effects, which retain a useful causal interpretation even when the propensity score model is misspecified, provided the outcome regression model is correctly specified. © 2014 John Wiley & Sons, Ltd.
Mertes H.,Ghent University
Journal of Assisted Reproduction and Genetics | Year: 2015
Purpose: A critical ethical analysis of the initiative of several companies to cover the costs of oocyte cryopreservation for their healthy employees. The main research question is whether such policies promote or confine women’s reproductive autonomy. Results: A distinction needs to be made between the ethics of AGE banking in itself and the ethics of employers offering it to their employees. Although the utility of the former is expected to be low, there are few persuasive arguments to deny access to oocyte cryopreservation to women who are well informed about the procedure and the success rates. However, it does not automatically follow that it would be ethically unproblematic for employers to offer egg banking to their employees. Conclusions: For these policies to be truly ‘liberating’, a substantial number of conditions need to be fulfilled, which can be reduced to three categories: (1) women should understand the benefits, risks and limitations, (2) women should feel no pressure to take up the offer; (3) the offer should have no negative effect on other family-friendly policies and should in fact be accompanied by such policies. Fulfilling these conditions may turn out to be impossible. Thus, regardless of companies’ possible good intentions, women’s reproductive autonomy is not well served by offering them company-sponsored AGE banking. © 2015, Springer Science+Business Media New York.
Lamkanfi M.,Ghent University |
Kanneganti T.-D.,St Jude Childrens Research Hospital
Cell Research | Year: 2012
Humans can be divided into roughly three groups with distinct microbial communities in their gastro-intestinal tract. The microbiota contributes to metabolic activity in the gastrointestinal tract of the host, but what mechanisms shape the composition of the gut microbiota, and how does a person's 'enterotype' affect metabolic processes in distant organs? Flavell and colleagues shed light on these questions by revealing an important role for inflammasomes in modulating the prevalence of colitogenic species, and by demonstrating that dysbiosis influences susceptibility to non-alcoholic steatohepatitis (NASH) and other manifestations of metabolic syndrome. © 2012 IBCB, SIBS, CAS All rights reserved.
Spilker T.,University of Michigan |
Vandamme P.,Ghent University |
LiPuma J.J.,University of Michigan
Journal of Clinical Microbiology | Year: 2012
The genus Achromobacter currently is comprised of seven species, including Achromobacter xylosoxidans, an opportunistic and nosocomial pathogen that displays broad-spectrum antimicrobial resistance and is recognized as causing chronic respiratory tract infection in persons with cystic fibrosis (CF). To enable strain typing for global epidemiologic investigations, to clarify the taxonomy of "Achromobacter-like" strains, and to elucidate the population structure of this genus, we developed a genus-level multilocus sequence typing (MLST) scheme. We employed in silico analyses of whole-genome sequences of several phylogenetically related genera, including Bordetella, Burkholderia, Cupriavidus, Herminiimonas, Janthinobacterium, Methylibium, and Ralstonia, for selecting loci and designing PCR primers. Using this MLST scheme, we analyzed 107 genetically diverse Achromobacter isolates cultured from biologic specimens from CF and non-CF patients, 1 isolate recovered from sludge, and an additional 39 strains obtained from culture collections. Sequence data from these 147 strains, plus three recently genome-sequenced Achromobacter strains, were assigned to 129 sequence types based on seven loci. Calculation of the nucleotide divergence of concatenated locus sequences within and between MLST clusters confirmed the seven previously named Achromobacter species and revealed 14 additional genogroups. Indices of association showed significant linkage disequilibrium in all of the species/genogroups able to be tested, indicating that each group has a clonal population structure. No clear segregation of species/genogroups between CF and non-CF sources was found. Copyright © 2012, American Society for Microbiology. All Rights Reserved.
Vandersickel N.,Ghent University |
Zwanziger D.,New York University
Physics Reports | Year: 2012
In 1967, Faddeev and Popov were able to quantize the Yang-Mills theory by introducing new particles called ghost through the introduction of a gauge. Ever since, this quantization has become a standard textbook item. Some years later, Gribov discovered that the gauge fixing was not complete, gauge copies called Gribov copies were still present and could affect the infrared region of quantities like the gauge dependent gluon and ghost propagator. This feature was often in the literature related to confinement. Some years later, the semi-classical approach of Gribov was generalized to all orders and the GZ action was born. Ever since, many related articles were published. This review tends to give a pedagogic review of the ideas of Gribov and the subsequent construction of the GZ action, including many other topics related to the Gribov region. It is shown how the GZ action can be viewed as a non-perturbative tool which has relations with other approaches toward confinement. Many different features related to the GZ action shall be discussed in detail, such as BRST breaking, the KO criterion, the propagators, etc. We shall also compare with the lattice data and other non-perturbative approaches, including stochastic quantization. © 2012 Elsevier B.V.
De Pauw S.S.,Ghent University
Child psychiatry and human development | Year: 2010
The numerous temperament and personality constructs in childhood impede the systematic integration of findings on how these individual differences relate to developmental psychopathology. This paper reviews the main temperament and personality theories and proposes a theoretical taxonomy representing the common structure of both temperament and personality traditions within one conceptual framework. This integrated lexicon of childhood temperament/personality traits facilitates an overview of the most important research findings on the role of temperament and personality in the development of anxiety, depression, ADHD, proactive and reactive antisocial behavior. Several directions for future research are discussed to further validate and refine these reviewed relationships.
De Paepe B.,Ghent University
Pediatric research | Year: 2012
Protons are pumped from the mitochondrial matrix via oxidative phosphorylation (OXPHOS) into the intermembrane space, creating an electric membrane potential (ΔΨ) that is used for adenosine triphosphate (ATP) production. Defects in one or more of the OXPHOS complexes are associated with a variety of clinical symptoms, often making it difficult to pinpoint the causal mutation. In this article, a microscopic method for the quantitative evaluation of ΔΨ in cultured skin fibroblasts is described. The method using 5,5',6,6'-tetraethylbenzimidazolyl-carbocyanine iodide (JC-1) fluorescence staining was tested in a selection of OXPHOS-deficient cell lines. A significant reduction of ΔΨ was found in the cell lines of patients with either an isolated defect in complex I, II, or IV or a combined defect (complex I + complex IV). ΔΨ was not reduced in the fibroblasts of two patients with severe complex V deficiency. Addition of the complex I inhibitor rotenone induced a significant reduction of ΔΨ and perinuclear relocalization of the mitochondria. In cells with a heteroplasmic mitochondrial DNA (mtDNA) defect, a more heterogeneous reduction of ΔΨ was detected. Our data show that imaging of ΔΨ in cultured skin fibroblasts is a useful method for the evaluation of OXPHOS functioning in cultured cell lines.
Szakonyi D.,John Innes Center |
Szakonyi D.,Ghent University |
Byrne M.E.,University of Sydney
Plant Journal | Year: 2011
Summary Ribosomal proteins are integral to ribosome biogenesis, and function in protein synthesis. In higher eukaryotes, loss of cytoplasmic ribosomal proteins results in a reduced growth rate as well as developmental defects. To what extent and how ribosomal proteins affect development is currently not known. Here we describe a semi-dominant mutation in the cytoplasmic ribosomal protein gene RPL27aC that affects multiple aspects of plant shoot development, including leaf patterning, inflorescence and floral meristem function, and seed set. In the embryo, RPL27aC is required to maintain the growth rate and for the transition from radial to bilateral symmetry associated with initiation of cotyledons. rpl27ac-1d embryos undergo stereotypical patterning to establish a globular embryo. However, a temporal delay in initiation and outgrowth of cotyledon primordia leads to development of an enlarged globular embryo prior to apical domain patterning. Defects in embryo development are coincident with tissue-specific ectopic expression of the shoot meristem genes SHOOT MERISTEMLESS (STM) and CUP-SHAPED COTYLEDON2 (CUC2), in addition to delayed expression of the abaxial gene FILAMENTOUS FLOWER (FIL) and mis-regulation of the auxin efflux effector PIN-FORMED1 (PIN1). Genetic interactions with other ribosomal protein mutants indicate that RPL27aC is a component of the ribosome. We propose that RPL27aC regulates discrete developmental events by controlling spatial and temporal expression of developmental patterning genes via an as yet undefined process involving the ribosome. © 2010 The Authors. The Plant Journal © 2010 Blackwell Publishing Ltd.
Koban L.,University of Colorado at Boulder |
Koban L.,University of Geneva |
Pourtois G.,Ghent University
Neuroscience and Biobehavioral Reviews | Year: 2014
Action monitoring allows the swift detection of conflicts, errors, and the rapid evaluation of outcomes. These processes are crucial for learning, adaptive behavior, and for the regulation of cognitive control. Our review discusses neuroimaging and electrophysiological studies that have explored the contribution of emotional and social factors during action monitoring. Meta-analytic brain activation maps demonstrate reliable overlap of error monitoring, emotional, and social processes in the dorsal mediofrontal cortex (dMFC), lateral prefrontal areas, and anterior insula (AI). Cumulating evidence suggests that action monitoring is modulated by trait anxiety and negative affect, and that activity of the dMFC and the amygdala during action monitoring might contribute to the 'affective tagging' of actions along a valence dimension. The role of AI in action monitoring may be the integration of outcome information with self-agency and social context factors, thereby generating more complex situation-specific and conscious emotional feeling states. Our review suggests that action-monitoring processes operate at multiple levels in the human brain, and are shaped by dynamic interactions with affective and social processes. © 2014 Elsevier Ltd.
Verbrugghe E.,Ghent University
Veterinary research | Year: 2012
The mycotoxin T-2 toxin and Salmonella Typhimurium infections pose a significant threat to human and animal health. Interactions between both agents may result in a different outcome of the infection. Therefore, the aim of the presented study was to investigate the effects of low and relevant concentrations of T-2 toxin on the course of a Salmonella Typhimurium infection in pigs. We showed that the presence of 15 and 83 μg T-2 toxin per kg feed significantly decreased the amount of Salmonella Typhimurium bacteria present in the cecum contents, and a tendency to a reduced colonization of the jejunum, ileum, cecum, colon and colon contents was noticed. In vitro, proteomic analysis of porcine enterocytes revealed that a very low concentration of T-2 toxin (5 ng/mL) affects the protein expression of mitochondrial, endoplasmatic reticulum and cytoskeleton associated proteins, proteins involved in protein synthesis and folding, RNA synthesis, mitogen-activated protein kinase signaling and regulatory processes. Similarly low concentrations (1-100 ng/mL) promoted the susceptibility of porcine macrophages and intestinal epithelial cells to Salmonella Typhimurium invasion, in a SPI-1 independent manner. Furthermore, T-2 toxin (1-5 ng/mL) promoted the translocation of Salmonella Typhimurium over an intestinal porcine epithelial cell monolayer. Although these findings may seem in favour of Salmonella Typhimurium, microarray analysis showed that T-2 toxin (5 ng/mL) causes an intoxication of Salmonella Typhimurium, represented by a reduced motility and a downregulation of metabolic and Salmonella Pathogenicity Island 1 genes. This study demonstrates marked interactions of T-2 toxin with Salmonella Typhimurium pathogenesis, resulting in bacterial intoxication.
Bachert C.,Ghent University
Allergologie | Year: 2015
The new S2k-guideline for allergen immunotherapy (AIT) for the first time provides product-specific Information for subcutaneous (SCIT) and sublingual (SLIT) products. This product-specific approach suggests the use of evidence-based and registered AIT products, which represent the first choice in the treatment decision. © 2015 Dustri-Verlag Dr. Karl Feistle.
Verschoor J.A.,University of Pretoria |
Baird M.S.,University of Wales |
Grooten J.,Ghent University
Progress in Lipid Research | Year: 2012
Mycolic acids constitute the waxy layer of the outer cell wall of Mycobacterium spp. and a few other genera. They are diverse in structure, providing a unique chromatographic foot-print for almost each of the more than 70 Mycobacterium species. Although mainly esterified to cell wall arabinogalactan, trehalose or glucose, some free mycolic acid is secreted during in vitro growth of Mycobacterium tuberculosis. In M. tuberculosis, α-, keto- and methoxy-mycolic acids are the main classes, each differing in their ability to attract neutrophils, induce foamy macrophages or adopt an antigenic structure for antibody recognition. Of interest is their particular relationship to cholesterol, discovered by their ability to attract cholesterol, to bind Amphotericin B or to be recognised by monoclonal antibodies that cross-react with cholesterol. The structural elements that determine this diverse functionality include the carboxylic acid in the mycolic motif, as well as the nature and stereochemistry of the two functional groups in the merochain. The functional diversity of mycolic acid classes implies that much information may be contained in the selective expression and secretion of mycolic acids to establish tuberculosis after infection of the host. Their cholesteroid nature may relate to how they utilize host cholesterol for their persistent survival. © 2012 Elsevier Ltd. All rights reserved.
Lang J.W.B.,Ghent University |
Lang J.W.B.,Maastricht University
Psychological Review | Year: 2014
The measurement of implicit or unconscious motives using the picture story exercise (PSE) has long been a target of debate in the psychological literature. Most debates have centered on the apparent paradox that PSE measures of implicit motives typically show low internal consistency reliability on common indices like Cronbach's alpha but nevertheless predict behavioral outcomes. I describe a dynamic Thurstonian item response theory (IRT) model that builds on dynamic system theories of motivation, theorizing on the PSE response process, and recent advancements in Thurstonian IRT modeling of choice data. To assess the models' capability to explain the internal consistency paradox, I first fitted the model to archival data (Gurin, Veroff, & Feld, 1957) and then simulated data based on bias-corrected model estimates from the real data. Simulation results revealed that the average squared correlation reliability for the motives in the Thurstonian IRT model was .74 and that Cronbach's alpha values were similar to the real data (<.35). These findings suggest that PSE motive measures have long been reliable and increase the scientific value of extant evidence from motivational research using PSE motive measures. © 2014 American Psychological Association.
Ceelen W.P.,Ghent University |
Flessner M.F.,University of Mississippi Medical Center
Nature Reviews Clinical Oncology | Year: 2010
In patients with tumors confined to the peritoneal cavity, there is established pharmacokinetic and tumor biology-related evidence that intraperitoneal drug administration is advantageous. Three large randomized trials in patients with stage III ovarian cancer who underwent optimal cytoreduction have demonstrated a significant survival benefit when intraperitoneal chemotherapy was added to systemic therapy. Although intraperitoneal therapy is associated with locoregional toxic effects, recent trials suggest that with some modification of the local delivery methods this approach is safe in 80% of patients in an ambulatory setting. Surgical cytoreduction immediately followed by intraoperative hyperthermic intraperitoneal chemoperfusion (HIPEC) ensures intraperitoneal delivery of the drug to all peritoneal surfaces and the advantages of combined hyperthermia to be exploited. An increasing number of centers are initiating this multimodality therapy in ovarian cancer and colorectal cancer. Clearly, intraperitoneal drug delivery is an important adjunct to surgery and systemic chemotherapy in selected patients. The optimal drug, dose and schedule for intraperitoneal delivery, the exact role of added HIPEC compared with cytoreduction alone, and the potential role of HIPEC in ovarian cancer and peritoneal mesothelioma are still undefined. Several randomized controlled trials addressing these uncertainties have been initiated. © 2010 Macmillan Publishers Limited. All rights reserved.
De Paepe B.,Ghent University
Cytokine | Year: 2015
Evidence accumulates implicating interferons (IFNs) in the chronic inflammation associated with the idiopathic inflammatory mypathies (IM). Dermatomyositis in particular appears to display a strong IFN type 1 signature. Proposed pathogenic actions of IFNs include the upregulation of major histocompatibility complex class I on muscle fibres, and the induction of a plethora of pro-inflammatory factors, including cytokines and chemokines. This review brings together findings on IFNs and IFN-induced factors, sketching their roles in IM immunopathogenesis in general and dermatomyositis in particular, and offering a basis for exploring their potential therapeutic relevance. © 2014 Elsevier Ltd.
Van Eenoo P.,Ghent University
Handbook of Experimental Pharmacology | Year: 2010
Two groups of substances which stimulate the adrenergic system are listed as prohibited by the World Anti-Doping Agency. Stimulants are prohibited in-competition only and β2-agonists are prohibited in- and out-of-competition. While β2-agonists act directly on the target receptors, sympathomimetic amines can exert their action directly and indirectly. Due to differences in pharmacology but mainly due to differences in administered dose, differences in detection methods between both groups of substances exist although preparation is similar and consists of an extraction at basic pH. Gas chromatography coupled to mass spectrometry has been the detection methodology of choice for several decades. However, the importance of liquid chromatography-mass spectrometry as a preferred detection methodology is rapidly increasing, especially for the detection of β2-agonists and new additions to the list of prohibited stimulants, such as modafinil. Pharmacology, metabolism and detection of both groups of prohibited substances will be discussed. © 2009 Springer-Verlag Berlin Heidelberg.
Versilovskis A.,Latvian Institute of Organic Synthesis |
de Saeger S.,Ghent University
Molecular Nutrition and Food Research | Year: 2010
Sterigmatocystin (STC) is a mycotoxin produced by fungi of many different Aspergillus species. Other species such as Bipolaris, Chaetomium, Emiricella are also able to produce STC. STC producing fungi were frequently isolated from different foodstuffs, while STC was regularly detected in grains, corn, bread, cheese, spices, coffee beans, soybeans, pistachio nuts, animal feed and silage. STC shows different toxicological, mutagenic and carcinogenic effects in animals and has been recognized as a 2B carcinogen (possible human carcinogen) by International Agency for Research on Cancer. There are more than 775 publications available in Scopus (and more than 505 in PubMed) mentioning STC, but there is no summary information available about STC occurrence and analysis in food. This review presents an overview of the worldwide information on the occurrence of STC in different foodstuffs during the last 40 years, and describes the progress made in analytical metho - dology for the determination of STC in food. © 2009 WILEY-VCH Verlag GmbH & Co.
Steyer R.,Friedrich - Schiller University of Jena |
Mayer A.,Ghent University |
Geiser C.,Utah State University |
Cole D.A.,Vanderbilt University
Annual Review of Clinical Psychology | Year: 2015
We present a revision of latent state-trait (LST-R) theory with new definitions of states and traits. This theory applies whenever we study the consistency of behavior, its variability, and its change over time. States and traits are defined in terms of probability theory. This allows for a seamless transition from theory to statistical modeling of empirical data. LST-R theory not only gives insights into the nature of latent variables but it also takes into account four fundamental facts: Observations are fallible, they never happen in a situational vacuum, they are always made using a specific method of observations, and there is no person without a past. Although the first fact necessitates considering measurement error, the second fact requires allowances for situational fluctuations. The third fact implies that, in the first place, states and traits are method specific. Furthermore, compared to the previous version of LST theory (see, e.g., Steyer et al. 1992, 1999), our revision is based on the notion of a person-at-time-t. The new definitions in LST-R theory have far-reaching implications that not only concern the properties of states, traits, and the associated concepts of measurement errors and state residuals, but also are related to the analysis of states and traits in longitudinal observational and intervention studies. © 2015 by Annual Reviews. All rights reserved.
Younes F.,Ghent University
European journal of oral implantology | Year: 2013
This retrospective cohort study evaluated metal-cast silan-coated three-unit resin-bonded fixed dental prostheses (RBFDPs) after at least 16 years and identified covariates affecting the survival. A total of 37 patients with 42 RBFDPs placed by one operator between 1986 and 1993 were recalled and invited for a clinical examination in conjunction with scrutiny of clinical records. Thirteen RBFDPs were lost to follow-up after an average of 58.5 months (SD = 39.4) and considered unaccounted for, 10 failed prior to the research recall and had a survival of 130.2 months (SD = 68.3), and 19 were still in function with a mean survival of 236.2 months (SD = 24.7). The estimated, cumulative survival via Kaplan-Meier analysis of the total number of 43 RBFDPs resulted in 95% (SE = 4%) survival after 5 years, 88% (SE = 6%) after 10 years and 66% (SE = 9%) after 20 years. No covariates were found having a significant effect on the survival rates. RBFDPs have an acceptable clinical survival although lower than conventional FDPs and single implants. They should therefore be considered as a temporary provision, as a provision for geriatric or medically-compromised patients because of the simplicity of the provision, as a less expensive alternative, and for patients where the amount of bone loss impedes the use of dental implants.
Elgar F.J.,McGill University |
Pfortner T.-K.,University of Cologne |
Moor I.,Martin Luther University of Halle Wittenberg |
De Clercq B.,Ghent University |
And 2 more authors.
The Lancet | Year: 2015
Background Information about trends in adolescent health inequalities is scarce, especially at an international level. We examined secular trends in socioeconomic inequality in five domains of adolescent health and the association of socioeconomic inequality with national wealth and income inequality. Methods We undertook a time-series analysis of data from the Health Behaviour in School-aged Children study, in which cross-sectional surveys were done in 34 North American and European countries in 2002, 2006, and 2010 (pooled n 492 788). We used individual data for socioeconomic status (Health Behaviour in School-aged Children Family Affluence Scale) and health (days of physical activity per week, body-mass index Z score [zBMI], frequency of psychological and physical symptoms on 0-5 scale, and life satisfaction scored 0-10 on the Cantril ladder) to examine trends in health and socioeconomic inequalities in health. We also investigated whether international differences in health and health inequalities were associated with per person income and income inequality. Findings From 2002 to 2010, average levels of physical activity (3·90 to 4·08 days per week; p<0·0001), body mass (zBMI -0·08 to 0·03; p<0·0001), and physical symptoms (3·06 to 3·20, p<0·0001), and life satisfaction (7·58 to 7·61; p=0·0034) slightly increased. Inequalities between socioeconomic groups increased in physical activity (-0·79 to -0·83 days per week difference between most and least affluent groups; p=0·0008), zBMI (0·15 to 0·18; p<0·0001), and psychological (0·58 to 0·67; p=0·0360) and physical (0·21 to 0·26; p=0·0018) symptoms. Only in life satisfaction did health inequality fall during this period (-0·98 to -0·95; p=0·0198). Internationally, the higher the per person income, the better and more equal health was in terms of physical activity (0·06 days per SD increase in income; p<0·0001), psychological symptoms (-0·09; p<0·0001), and life satisfaction (0·08; p<0·0001). However, higher income inequality uniquely related to fewer days of physical activity (-0·05 days; p=0·0295), higher zBMI (0·06; p<0·0001), more psychological (0·18; p<0·0001) and physical (0·16; p<0·0001) symptoms, and larger health inequalities between socioeconomic groups in psychological (0·13; p=0·0080) and physical (0·07; p=0·0022) symptoms, and life satisfaction (-0·10; p=0·0092). Interpretation Socioeconomic inequality has increased in many domains of adolescent health. These trends coincide with unequal distribution of income between rich and poor people. Widening gaps in adolescent health could predict future inequalities in adult health and need urgent policy action. Funding Canadian Institutes of Health Research. © 2015 Elsevier Ltd.
Eggermont M.,Ghent University
Archives of Gynecology and Obstetrics | Year: 2015
Purpose: To develop juridical recommendations to reduce medical liability of the obstetrician, providing intrapartum care. Methods: 107 legal proceedings of the past 40 years from Belgium, France and the Netherlands, involving medical negligence of the obstetrician during intrapartum care, were analyzed in depth. The legal databases used were Jura and Judit (Belgium), Legifrance, Juricaf and Dalloz (France) and Recht, Rechtspraak (the Netherlands). A minority of the cases were retrieved through contacts with insurance companies (Belgium only) and courts. Results: The judicial assessment of negligence is focused on four domains of expertise of the obstetrician: 36 % (38/107) recognizing a specific pathology, 33 % (35/107) interpreting fetal monitoring, 19 % (21/107) performing a forceps/vacuum-assisted delivery and 12 % (13/107) managing shoulder dystocia. The highest liability rate of 86 % (30/35) was reflected in the category of interpreting fetal monitoring. Conclusion: To reduce the liability rate of 66 %, several policy recommendations can be made. Respond to the first symptoms of obstetric complications (particularly placental abruption and uterine rupture). Secondly, respond to disturbing messages of the midwife concerning fetal distress and evaluate every deviation in fetal heart rate monitoring. Education concerning the interpretation of fetal monitoring is a must for every midwife and obstetrician. Use proper methods to monitor the heart rate to optimize the quality of the signal. The third recommendation is to be cautious about opting for a forceps/vacuum-assisted delivery, consider all circumstances. Consider the risk of failed instrumental delivery. And finally in relation to shoulder dystocia, recognize the risk factors by ordering further examinations to purchase a diagnosis. © 2015, Springer-Verlag Berlin Heidelberg.
Julvez J.J.,University of Zaragoza |
Boel R.K.,Ghent University
IEEE Transactions on Systems, Man, and Cybernetics Part A:Systems and Humans | Year: 2010
Traffic systems are often highly populated discrete event systems that exhibit several modes of behavior such as free flow traffic, traffic jams, stop-and-go waves, etc. An appropriate closed loop control of the congested system is crucial in order to avoid undesirable behavior. This paper proposes a macroscopic model based on continuous Petri nets as a tool for designing control laws that improve the behavior of traffic systems. The main reason to use a continuous model is to avoid the state explosion problem inherent to large discrete event systems. The obtained model captures the different operation modes of a traffic system and is highly compositional. In order to handle the variability of the traffic conditions, a model predictive control strategy is proposed and validated. © 2010 IEEE.
Van Lijsebettens M.,Vlaams Institute for Biotechnology |
Van Lijsebettens M.,Ghent University |
Grasser K.D.,University of Regensburg
Trends in Plant Science | Year: 2014
Elongation is a dynamic and highly regulated step of eukaryotic gene transcription. A variety of transcript elongation factors (TEFs), including modulators of RNA polymerase II (RNAPII) activity, histone chaperones, and histone modifiers, have been characterized from plants. These factors control the efficiency of transcript elongation of subsets of genes in the chromatin context and thus contribute to tuning gene expression programs. We review here how genetic and biochemical analyses, primarily in Arabidopsis thaliana, have advanced our understanding of how TEFs adjust plant gene transcription. These studies have revealed that TEFs regulate plant growth and development by modulating diverse processes including hormone signaling, circadian clock, pathogen defense, responses to light, and developmental transitions. © 2014 Elsevier Ltd.
Van de Peer Y.,VIB |
Van de Peer Y.,Ghent University
Genome Biology | Year: 2011
A recent phylogenomic study has provided new evidence for two ancient whole genome duplications in plants, with potential importance for the evolution of seed and flowering plants.
Verhoeven K.,Ghent University
European journal of pain (London, England) | Year: 2012
Distraction is an intuitive way of coping with pain and is often used in children's pain treatment programs. However, empirical evidence concerning the effectiveness of distraction is equivocal. One potential explanation might be that distraction does not work for everyone in every situation. In the current series of studies, we examined the role of pain catastrophizing as an influencing factor of distraction effectiveness. In the first study, we investigated the use of pain coping strategies (including distraction) in schoolchildren (N = 828, aged 8-18 years) by means of a questionnaire. Results indicated that children with higher levels of pain catastrophizing reported using less distraction strategies in daily life than children with lower levels of pain catastrophizing. In the second study, a subsample (N = 81, aged 9-18 years) performed a painful cold pressor task (CPT) (12 °C). Participants were randomly assigned to a distraction group, in which an attention-demanding tone-detection task was performed during the CPT, or a control group, in which no distraction task was performed. Results showed that participants in the distraction group were engaged in the distraction task, and reported to have paid less attention to pain than participants in the control group. However, distraction was ineffective in reducing cold pressor pain, and even intensified the pain experience in high catastrophizing children. Caution may be warranted in using distraction as a 'one size fits all' method, especially in high catastrophizing children. © 2011 European Federation of International Association for the Study of Pain Chapters.
Starheim K.K.,University of Bergen |
Gevaert K.,VIB |
Gevaert K.,Ghent University |
Arnesen T.,University of Bergen
Trends in Biochemical Sciences | Year: 2012
The majority of eukaryotic proteins are subjected to N-terminal acetylation (Nt-acetylation), catalysed by N-terminal acetyltransferases (NATs). Recently, the structure of an NAT-peptide complex was determined, and detailed proteome-wide Nt-acetylation patterns were revealed. Furthermore, Nt-acetylation just emerged as a multifunctional regulator, acting as a protein degradation signal, an inhibitor of endoplasmic reticulum (ER) translocation, and a mediator of protein complex formation. Nt-acetylation is regulated by acetyl-coenzyme A (Ac-CoA) levels, and thereby links metabolic cell states to cell death. The essentiality of NATs in humans is stressed by the recent discovery of a human hereditary lethal disease caused by a mutation in an NAT gene. Here, we discuss how these recent findings shed light on NATs as major protein regulators and key cellular players. © 2012 Elsevier Ltd.
Frenkel J.,Friedrich - Schiller University of Jena |
Vyverman W.,Ghent University |
Pohnert G.,Friedrich - Schiller University of Jena
Plant Journal | Year: 2014
Algae are found in all aquatic and many terrestrial habitats. They are dominant in phytoplankton and biofilms thereby contributing massively to global primary production. Since algae comprise photosynthetic representatives of the various protoctist groups their physiology and appearance is highly diverse. This diversity is also mirrored in their characteristic life cycles that exhibit various facets of ploidy and duration of the asexual phase as well as gamete morphology. Nevertheless, sexual reproduction in unicellular and colonial algae usually has as common motive that two specialized, sexually compatible haploid gametes establish physical contact and fuse. To guarantee mating success, processes during sexual reproduction are highly synchronized and regulated. This review focuses on sex pheromones of algae that play a key role in these processes. Especially, the diversity of sexual strategies as well as of the compounds involved are the focus of this contribution. Discoveries connected to algal pheromone chemistry shed light on the role of key evolutionary processes, including endosymbiotic events and lateral gene transfer, speciation and adaptation at all phylogenetic levels. But progress in this field might also in the future provide valid tools for the manipulation of aquaculture and environmental processes. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.
Vanderweele T.J.,Harvard University |
Vansteelandt S.,Ghent University
American Journal of Epidemiology | Year: 2011
Estimates of additive interaction from case-control data are often obtained by logistic regression; such models can also be used to adjust for covariates. This approach to estimating additive interaction has come under some criticism because of possible misspecification of the logistic model: If the underlying model is linear, the logistic model will be misspecified. The authors propose an inverse probability of treatment weighting approach to causal effects and additive interaction in case-control studies. Under the assumption of no unmeasured confounding, the approach amounts to fitting a marginal structural linear odds model. The approach allows for the estimation of measures of additive interaction between dichotomous exposures, such as the relative excess risk due to interaction, using case-control data without having to rely on modeling assumptions for the outcome conditional on the exposures and covariates. Rather than using conditional models for the outcome, models are instead specified for the exposures conditional on the covariates. The approach is illustrated by assessing additive interaction between genetic and environmental factors using data from a case-control study. © 2011 The Author.
Depla D.,Ghent University
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2014
The effective sputter yield during magnetron sputtering of elemental targets was measured by weighing the target before and after sputtering at constant discharge voltage. During the experiment, the pressure and discharge current were logged. The effective sputter yield is compared with a set of published semi-empirical equations to calculate the sputter yield for ion/solid interactions. The differences between both yields are discussed based on different contributions which affect the effective sputter yield such as redeposition, the target roughness and the contribution of high energetic neutrals. © 2014 Elsevier B.V. All rights reserved.
De Backer G.G.,Ghent University
Current Atherosclerosis Reports | Year: 2014
The importance of total cardiovascular (CV) risk estimation before management decisions are taken is well established. Models have been developed that allow physicians to stratify the asymptomatic population in subgroups at low, moderate, high, and very high total CV risk. Most models are based on classical CV risk factors: age, gender, smoking, blood pressure, and lipid levels. The impact of additional risk factors is discussed here, looking separately at the predictive increments of novel biomarkers and of indicators of subclinical atherosclerotic disease. The contribution of biomarkers to the total CV risk estimation is generally modest, and their usage should be limited to subjects at intermediate total CV risk. Detection of subclinical vascular damage may improve total CV risk estimation in asymptomatic subjects who are close to a threshold that could affect management decisions and in whom the chances of re-classification in a different risk category are great. There is, however, an urgent need for trials in which the value of using total CV risk estimation models is tested. © 2014 Springer Science+Business Media.
Murphy E.,University of Nottingham |
De Smet I.,University of Nottingham |
De Smet I.,Ghent University
Trends in Plant Science | Year: 2014
Small secreted peptides are gaining importance as signalling molecules in plants. Among the 1000 open reading frames (ORFs) in the Arabidopsis (Arabidopsis thaliana) genome potentially encoding small secreted peptides, the members of the RAPID ALKALINIZATION FACTOR (RALF) family of peptides have been linked to several physiological and developmental processes. Here, we provide a comprehensive overview of current knowledge on the RALF family. Discovered in tobacco (Nicotiana tabacum), the role of RALF peptides has been investigated in numerous plant species. Together, these observations suggest that RALF peptides impact on acidification and cell expansion during growth and development. Although few components of the signalling pathway have been revealed, the recent identification of FERONIA (FER) as a RALF receptor and plasma membrane H+-ATPase 2 as a downstream target provide a major step forward. © 2014 Elsevier Ltd.
de Poel B.V.,University of Maryland University College |
Van Der Straeten D.,Ghent University
Frontiers in Plant Science | Year: 2014
Ethylene is a simple two carbon atom molecule with profound effects on plants. There are quite a few review papers covering all aspects of ethylene biology in plants, including its biosynthesis, signaling and physiology. This is merely a logical consequence of the fascinating and pleiotropic nature of this gaseous plant hormone. Its biochemical precursor, 1-aminocyclopropane-1-carboxylic acid (ACC) is also a fairly simple molecule, but perhaps its role in plant biology is seriously underestimated. This triangularly shaped amino acid has many more features than just being the precursor of the lead-role player ethylene. For example, ACC can be conjugated to three different derivatives, but their biological role remains vague. ACC can also be metabolized by bacteria using ACC-deaminase, favoring plant growth and lowering stress susceptibility. ACC is also subjected to a sophisticated transport mechanism to ensure local and long-distance ethylene responses. Last but not least, there are now a few exciting studies where ACC has been reported to function as a signal itself, independently from ethylene. This review puts ACC in the spotlight, not to give it the lead-role, but to create a picture of the stunning co-production of the hormone and its precursor. © 2014 Van de Poel and Van Der Straeten.
Willems J.L.,Ghent University
IEEE Transactions on Instrumentation and Measurement | Year: 2011
This paper deals with the concepts of reactive power and reactive current in a nonsinusoidal periodic situation. It is shown that there exists a close relationship between the definitions proposed by Budeanu, Tenti, and Kusters and Moore. A new result is derived associated with the well-known Budeanu reactive power concept. © 2006 IEEE.
Verhoeven G.J.J.,Ghent University
International Journal of Remote Sensing | Year: 2010
Current one-shot, handheld Digital Still Cameras (DSCs) generally offer different file formats to save the captured frames: Joint Photographic Experts Group (JPEG), RAW and/or Tag(ged) Image File Format (TIFF). Although the JPEG file format is the most commonly used file format worldwide, it is incapable of storing all original data, something that also occurs, to a certain extent, for large TIFF files. Therefore, most professional photographers prefer shooting RAW files, often described as the digital photography's equivalent of a film negative. As a RAW file contains the absolute maximum amount of information and original data generated by the sensor, it is the only scientifically justifiable file format. In addition, its tremendous flexibility in both processing and postprocessing also makes it beneficial from a workflow and image quality point of view. On the other hand, large file sizes, the required software and proprietary file formats remain hurdles that are often too difficult to overcome for many photographers. Aerial photographers who shoot with handheld DSCs should be familiar with both RAW and other file formats, as their implications cannot be neglected. By outlining the complete process from photon capture to the generation of pixel values, additionally illustrated by real-world examples, the advantages and particularities of RAW aerial photography should become clear. © 2010 Taylor & Francis.
Leroux-Roels G.,Ghent University
Medical Microbiology and Immunology | Year: 2015
The safety and immunogenicity profiles of currently available recombinant hepatitis B vaccines are excellent. However, it remains a real challenge to induce protective immunity in the target groups that respond poorly or not at all to conventional vaccines. Ideally, a hepatitis B vaccine can be developed that conveys lifelong protection against infection rapidly after the injection of a single dose. Although this goal is far from being reached, important improvements have been made. Novel vaccine adjuvants have been developed that enhance the immunogenicity of recombinant hepatitis B vaccines while maintaining a good safety profile. The different adjuvants and adjuvant systems that are discussed herein have all been thoroughly evaluated in clinical trials and some have reached or are close to reach the market. © 2014, Springer-Verlag Berlin Heidelberg.
Mestdagh P.,Ghent University
Nucleic acids research | Year: 2011
While a growing body of evidence implicates regulatory miRNA modules in various aspects of human disease and development, insights into specific miRNA function remain limited. Here, we present an innovative approach to elucidate tissue-specific miRNA functions that goes beyond miRNA target prediction and expression correlation. This approach is based on a multi-level integration of corresponding miRNA and mRNA gene expression levels, miRNA target prediction, transcription factor target prediction and mechanistic models of gene network regulation. Predicted miRNA functions were either validated experimentally or compared to published data. The predicted miRNA functions are accessible in the miRNA bodymap, an interactive online compendium and mining tool of high-dimensional newly generated and published miRNA expression profiles. The miRNA bodymap enables prioritization of candidate miRNAs based on their expression pattern or functional annotation across tissue or disease subgroup. The miRNA bodymap project provides users with a single one-stop data-mining solution and has great potential to become a community resource.
Haerens L.,Ghent University
Public health nutrition | Year: 2010
To explore the relationship between several physical activity (PA) and dietary behaviours and BMI Z-score and to investigate the relationship between changes in these variables and in the BMI Z-score over a 4-year period from childhood to adolescence. Longitudinal study in which children were included in the fifth grade and measured for four consecutive years. Dietary and PA behaviours as well as height and weight were measured by means of self-reported validated questionnaires. Fifty-nine Flemish elementary schools. The baseline sample consisted of 51·9 % boys and the mean age was 10 (sd 0·4) years. During the first measurement year (2002), data on 1670 fifth graders were gathered. These measurements were repeated after 1 (n 1557), 2 (n 1151) and 3 (n 807) years. Significant inverse relationships with BMI Z-score were observed for frequency of breakfast consumption (β = -0·033, se = 0·012) and frequency of sports participation (β = -0·011, se = 0·004) across four time points. Significant inverse relationships between changes in BMI Z-score and changes in frequency of sports participation (β = -0·011, se = 0·006) and hours of physical education (PE; β = -0·052, se = 0·023) were observed, meaning that decreases in sports participation and hours spent in PE were associated with increases in BMI Z-score. The present study provides an important insight into different dietary and PA behaviours related to (changes in) BMI Z-score during the transition from childhood to adolescence.
Devreese K.,Ghent University |
Peerlinck K.,Catholic University of Leuven |
Hoylaerts M.F.,Catholic University of Leuven
Blood | Year: 2010
Lupus anticoagulants (LACs) are associated with thromboembolic complications (TECs). LACs can be detected by their anticoagulant properties in thrombin generation assays, by the peak height (PH) and lag time (LT). To assess the thrombotic risk in LAC-positive patients, we have expressed the LAC activity quantitatively by PH/LT calibration curves, constructed for mixtures of monoclonal antibodies against β2-glycoprotein I (β2GPI) and prothrombin, spiked in normal plasma. PH/LT was determined in LAC patients, with (n = 38) and without (n = 21) TECs and converted into arbitrary LAC units. LAC titers ranged from 0 to 200 AU/mL, with 5 of 59 patients being negative. In the positive LAC titer population (54 of 59), LAC and anti-β2GPI immunoglobulin G (IgG) titers correlated with TECs, with odds ratios of 3.54 (95% CI, 1.0-1.7) and 10.0 (95% CI, 1.98-50.6), respectively. In patients with single or combined low titers, useful predictions on thrombosis could be made only after additional measurements of soluble Pselectin and factor VII. This layered strategy yielded positive and negative predictive values, sensitivity, and specificity values approximately 90% in this subgroup. Hence, LAC and anti-β2GPI IgG titers, when combined with selected markers of the hypercoagulable state, allow a relevant thrombotic risk assessment in nearly all patients with LACs. © 2010 by The American Society of Hematology.
Lorente L.,Hospital Universitario Of Canarias |
Blot S.,Ghent University |
Rello J.,Institute Of Recerca Vall Dhebron
American Journal of Respiratory and Critical Care Medicine | Year: 2010
In the past 2 years, American, Canadian, and European scientific societies have published their new evidence-based guidelines for ventilator-associated pneumonia (VAP) prevention. However, these guidelines did not review some potentially useful strategies, such as the use of an endotracheal tube with an ultrathin cuff membrane, an endotracheal tube with a low-volume/low-pressure cuff, a device for continuous monitoring of the endotracheal tube cuff pressure, a device to remove biofilm from the inner site of the endotracheal tube, and saline instillation before tracheal suctioning. Only a few guidelines analyze the time of tracheostomy, and so no firm recommendations can be made regarding its importance. In addition, the guidelines diverge on the use of heat and moisture exchangers or heated humidifiers and on the use of an endotracheal tube coated with antimicrobial agents. The current review focuses on measures of VAP prevention for which there is no clear recommendation, or the use of which is controversial. A review of the literature suggests that the use of an endotracheal tube with an ultrathin and tapered-shape cuffmembrane and coated in antimicrobial agents may reduce the risk of VAP. These features offer an attractive way to optimize the VAP prevention capacity of endotracheal tubeswitha lumenfor subglottic secretion drainage. We believe that early tracheostomy should be considered, based on the length reduction of mechanical ventilation and intensive care unit stay, reduction of mortality, and on patient comfort, although early tracheostomy has not yet been shown to favorably impact the incidence of VAP. We believed that heat and moisture exchangers should be considered based on the benefits in terms of cost savings. More research is necessary to clarify the role of continuous cuff pressure monitoring, removal of biofilm formation in the endotracheal tubes, and routine saline instillation before tracheal suctioning.
Paemeleire K.,Ghent University |
Bartsch T.,University of Kiel
Neurotherapeutics | Year: 2010
Occipital nerve stimulation (ONS) was originally described in the treatment of occipital neuralgia. However, the spectrum of possible indications has expanded in recent years to include primary headache disorders, such as migraine and cluster headaches. Retrospective and some prospective studies have yielded encouraging results, and evidence from controlled clinical trials is emerging, offering hope for refractory headache patients. In this article we discuss the scientific rationale to use ONS to treat headache disorders, with emphasis on the trigeminocervical complex. ONS is far from a standardized technique at the moment and the recent literature on the topic is reviewed, both with respect to the procedure and its possible complications. An important way to move forward in the scientific evaluation of ONS to treat refractory headache is the clinical phenotyping of patients to identify patients groups with the highest likelihood to respond to this modality of treatment. This requires multidisciplinary assessment of patients. The development of ONS as a new treatment for refractory headache offers an exciting prospect to treat our most disabled headache patients. Data from ongoing controlled trials will undoubtedly shed new light on some of the unresolved questions. © 2010 The American Society for Experimental NeuroTherapeutics, Inc.
Vanhellemont J.,Ghent University
Journal of Crystal Growth | Year: 2012
The incorporation of intrinsic point defects during silicon crystal growth from the melt is discussed using recent data for intrinsic point defect thermal equilibrium and diffusivity. It is shown that the impact of compressive stress on the thermal equilibrium concentration and diffusivity of vacancies and self-interstitials should be taken into account. An analytical expression is derived to quantify the relation between crystal diameter and the critical pull rate window to grow defect free crystals. The results are compared with published experimental data on grown-in defect formation for crystal diameters ranging from 1 to 40 cm. It is shown that both the thermal stress due to the axial thermal gradient at the melt/solid interface and the silicon yield stress at high temperature play a crucial role. An empirical expression is proposed to describe the dependence of the thermal gradient on pulling rate. © 2011 Elsevier B.V.
Devreese K.,Ghent University |
Hoylaerts M.F.,Catholic University of Leuven
Clinical Chemistry | Year: 2010
BACKGROUND: The antiphospholipid syndrome (APS) is an important cause of acquired thromboembolic complications and pregnancy morbidity. Its diagnosis is based on clinical and laboratory criteria, defined by strict guidelines. The original clinical and laboratory criteria for the identification of APS patients were published in 1999, in the so-called Sapporo criteria. In 2006 these criteria were revised, and recently more precise guidelines for analysis of the lupus anticoagulant have been provided. However, several questions related to the diagnosis of APS remain unanswered. CONTENT: In addition to providing a historical perspective, this review covers several challenges in the diagnosis of APS with respect to clinical and laboratory features, while highlighting pathogenic pathways of the syndrome. We discuss ongoing dilemmas in the diagnosis of this complex disease. Although antiphospholipid antibodies are found in association with various clinical manifestations, the older established clinical criteria were not substantively altered in the 2006 update. Several laboratory tests recommended in the latest criteria, including phospholipid-dependent coagulation tests for the detection of the lupus anticoagulant and ELISAs for measuring anticardiolipin and β2-glycoprotein I antibodies, still show methodological and diagnostic shortcomings. In addition, antiphospholipid antibodies have been described against other antigens, but their clinical role remains uncertain. CONCLUSIONS: Despite updated APS criteria, diagnosis of this syndrome remains challenging. Further research on clinically relevant antibodies and standardization of their detection are needed to improve clinical risk assessment in APS. © 2010 American Association for Clinical Chemistry.
Vanholder R.,Ghent University
Clinical Journal of the American Society of Nephrology | Year: 2013
Crush syndrome is the second most common cause of death after earthquakes (the first most common is direct trauma). Many logistic problems with the treatment of patients with crush syndrome are due to chaotic disaster circumstances; consequently, medical and logistic recommendations on the treatment of crush victims are needed. In a joint initiative of the Renal Disaster Relief Task Force of the International Society of Nephrology and European Renal Best Practice, a work group of nephrologists, intensivists, surgeons, and logisticians with disaster experience or experts in guideline preparation collaborated to provide comprehensive information and recommendations on the management of crush casualties considering their occurrence with "epidemic" dimensions after mass disasters. The result is the monograph "Recommendations for the Management of Crush Victims inMass Disasters", which may help provide effective health care to disaster victims with renal problems. This article discussesmedical and logistic principles of the treatment of crush victims, both at the disaster field and on admission to hospitals, and guidance is described. The importance of early fluid administration even before extrication of the victims and avoidance of potassium-containing solutions during the treatment of crush victims is underlined. Also, the logistic problems in treating crush casualties are emphasized. Themost important aspects of the recently published recommendations are highlighted. © 2013 by the American Society of Nephrology.
Kuhn S.,Ghent University
Translational psychiatry | Year: 2011
Video game playing is a frequent recreational activity. Previous studies have reported an involvement of dopamine-related ventral striatum. However, structural brain correlates of video game playing have not been investigated. On magnetic resonance imaging scans of 154 14-year-olds, we computed voxel-based morphometry to explore differences between frequent and infrequent video game players. Moreover, we assessed the Monetary Incentive Delay (MID) task during functional magnetic resonance imaging and the Cambridge Gambling Task (CGT). We found higher left striatal grey matter volume when comparing frequent against infrequent video game players that was negatively correlated with deliberation time in CGT. Within the same region, we found an activity difference in MID task: frequent compared with infrequent video game players showed enhanced activity during feedback of loss compared with no loss. This activity was likewise negatively correlated with deliberation time. The association of video game playing with higher left ventral striatum volume could reflect altered reward processing and represent adaptive neural plasticity.
Declercq T.,Ghent University
The Cochrane database of systematic reviews | Year: 2013
Antipsychotic agents long-term use for this indication. Their effectiveness is limited and there is concern about adverse effects, including higher mortality with long-term use. When behavioural strategies have failed and drug therapy is instituted, regular attempts to withdraw these drugs are recommended. measures. Our primary efficacy outcomes were success of withdrawal (i.e. remaining in study off antipsychotics) and NPS. Eight of nine trials significantly shorter in the discontinuation group (Chi(2) = 4.1, P value = 0.04). The ninth trial included people with psychosis or (NPI)-core score of 30% or greater (P value = 0.004, hazard ratio (HR) 1.94, 95% confidence interval (CI) 1.09 to 3.45 at four months). The only outcome that could be pooled was the full NPI-score, used in two months (mean difference (MD) -1.49, 95% CI -5.39 to 2.40). These two studies reported subgroup analyses according to baseline NPI-score (14 or less versus > 14). In one study, those with milder symptoms at discontinuation group (NPI-agitation, Mann-Whitney U test z = 2.4, P value = 0.018). In both studies, there was evidence of significant behavioural deterioration in people with more severe baseline NPS who were withdrawn from antipsychotics (Chi(2) = 6.8; P value = 0.009 for the marked symptom score in one study).Individual studies did not report (5% to 8% greater than placebo, depending on the population analysed, measured at 12 months). This trend became significant three years after randomisation, but due to dropout and uncertainty about the use of withdrawal might not be recommended.
Verheest F.,Ghent University
Physics of Plasmas | Year: 2010
Using a Sagdeev pseudopotential formalism where nonlinear structures are stationary in a comoving frame, large dust-acoustic solitary waves and double layers have been studied in plasmas with negative cold dust or heavier ions, in the presence of nonthermal electrons and protons/positrons. The existence domain of negative solitary waves is limited by infinite compression of the negative dust or heavy ion species, that of positive solitary waves by the occurrence of positive double layers. These double layers require a sufficient degree of nonthermality of the hot species. There are parameter ranges where both negative and positive solitary structures can occur; sometimes both of the solitary wave type or sometimes one solitary wave and the other a double layer. Great emphasis is placed on the determination of the existence domains in compositional parameter space, with the help of strong analytical results, before typical Sagdeev pseudopotentials and solitary wave profiles are presented. Subject to simple adjustments, these results apply equally to a conjugate plasma model of positive dust or heavy ions, together with nonthermal electrons and protons/positrons. © 2010 American Institute of Physics.
de Bleecker J.,Ghent University
Molecular Psychiatry | Year: 2015
Pathological expansion of a G4C2 repeat, located in the 5' regulatory region of C9orf72, is the most common genetic cause of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). C9orf72 patients have highly variable onset ages suggesting the presence of modifying factors and/or anticipation. We studied 72 Belgian index patients with FTLD, FTLD–ALS or ALS and 61 relatives with a C9orf72 repeat expansion. We assessed the effect of G4C2 expansion size on onset age, the role of anticipation and the effect of repeat size on methylation and C9orf72 promoter activity. G4C2 expansion sizes varied in blood between 45 and over 2100 repeat units with short expansions (45–78 units) present in 5.6% of 72 index patients with an expansion. Short expansions co-segregated with disease in two families. The subject with a short expansion in blood but an indication of mosaicism in brain showed the same pathology as those with a long expansion. Further, we provided evidence for an association of G4C2 expansion size with onset age (P<0.05) most likely explained by an association of methylation state of the 5' flanking CpG island and expansion size in blood (P<0.0001) and brain (P<0.05). In several informative C9orf72 parent–child transmissions, we identified earlier onset ages, increasing expansion sizes and/or increasing methylation states (P=0.0034) of the 5' CpG island, reminiscent of disease anticipation. Also, intermediate repeats (7–24 units) showed a slightly higher methylation degree (P<0.0001) and a decrease of C9orf72 promoter activity (P<0.0001) compared with normal short repeats (2–6 units). Decrease of transcriptional activity was even more prominent in the presence of small deletions flanking G4C2 (P<0.0001). Here we showed that increased methylation of CpGs in the C9orf72 promoter may explain how an increasing G4C2 size lead to loss-of-function without excluding repeat length-dependent toxic gain-of-function. These data provide insights into disease mechanisms and have important implications for diagnostic counseling and potential therapeutic approaches.Molecular Psychiatry advance online publication, 20 October 2015; doi:10.1038/mp.2015.159. © 2015 Macmillan Publishers Limited
van Oostrum N.,Ghent University
Human reproduction (Oxford, England) | Year: 2013
Is bacterial vaginosis (BV) associated with the cause of infertility and does BV impinge on conception rates and early pregnancy loss following IVF? The incidence of BV is significantly higher among patients with tubal infertility when compared with patients with non-tubal infertility. BV does not impinge on conception rates but is significantly associated with preclinical pregnancy loss, though not with first trimester abortion. BV is prevalent in patients with infertility, as evident from studies across the world. This study is a meta-analysis of data on the prevalence of BV in women with infertility, the association between BV and the cause of infertility, and the associations between BV and conception rates and early pregnancy loss following IVF. The meta-analyses of the various topics involved different numbers of studies: prevalence of BV with infertility--12 studies, association with tubal infertility--3 studies and associations with conception rates--6 studies, with early preclinical pregnancy loss--2 studies and with clinical pregnancy loss--4 studies. Systematic literature searches of the electronic databases, PubMed, EMBASE, CINAHL, the Cochrane Library and ISI Web of Knowledge were performed up to September 2012. Studies were included if they reported on, at least, one of the following: prevalence of BV in infertility patients, association between BV and the cause of infertility, association between BV and conception rates with IVF or association between BV and early pregnancy loss. Studies were considered eligible if BV was diagnosed through standardized criteria like Nugent's criteria or Hay-Ison's criteria. In none of the studies, infertility as such was defined, but patients were described as unselected patients undergoing IVF. The estimated prevalence of BV (Nugent score >6) in infertile women is 19% [95% confidence interval (CI): 14-25%]. Abnormal microflora including BV and intermediate microflora (Nugent scores 4-10) occurs in 39% of the infertile patients (95% CI: 26-52%). BV is significantly more prevalent in women with infertility compared with antenatal women in the same population [OR (odds ratio) 3.32, 95% CI 1.53-7.20]. BV is significantly more prevalent in women with tubal infertility compared with women with other causes of infertility (OR 2.77, 95% CI 1.62-4.75). BV is not associated with decreased conception rates (OR 1.03, 95% CI 0.79-1.33). Similarly, none of the studies found an association between abnormal vaginal flora and conception rates following IVF treatment. BV is associated with a significantly elevated risk of preclinical pregnancy loss (OR 2.36, 95% CI: 1.24-4.51). BV is not associated with an increased risk of first trimester miscarriage (OR 1.20, 95%CI: 0.53-2.75). All included studies were centre based. In addition, publication bias cannot be ruled out. Furthermore, all estimates are obtained using an absolute minimum of studies. The standard error on the estimates is so large that it does not allow for any formal statistical conclusions regarding heterogeneity between the effects reported in different studies. It needs to be recognized that most inferences drawn in our study rely on a limited number of studies, potentially, endangering the generalizability of our findings. Moreover, all studies on cause of infertility in relation to BV included had a cross-sectional design and, therefore, do not allow for causal inferences. Still, there is strong circumstantial evidence that supports a causal link between BV and tubal infertility. Studies with a longitudinal design, on the other hand, strongly support a relation between BV and early pregnancy loss. Unfortunately, no study looked beyond first trimester fetal loss, although it is plausible that the high preterm birth rates with IVF are, at least, in part attributable to BV.
Burger R.,University of Concepcion |
Diehl S.,Lund University |
Nopens I.,Ghent University
Water Research | Year: 2011
The aim of this contribution is partly to build consensus on a consistent modelling methodology (CMM) of complex real processes in wastewater treatment by combining classical concepts with results from applied mathematics, and partly to apply it to the clarification-thickening process in the secondary settling tank. In the CMM, the real process should be approximated by a mathematical model (process model; ordinary or partial differential equation (ODE or PDE)), which in turn is approximated by a simulation model (numerical method) implemented on a computer. These steps have often not been carried out in a correct way. The secondary settling tank was chosen as a case since this is one of the most complex processes in a wastewater treatment plant and simulation models developed decades ago have no guarantee of satisfying fundamental mathematical and physical properties. Nevertheless, such methods are still used in commercial tools to date. This particularly becomes of interest as the state-of-the-art practice is moving towards plant-wide modelling. Then all submodels interact and errors propagate through the model and severely hamper any calibration effort and, hence, the predictive purpose of the model. The CMM is described by applying it first to a simple conversion process in the biological reactor yielding an ODE solver, and then to the solid-liquid separation in the secondary settling tank, yielding a PDE solver. Time has come to incorporate established mathematical techniques into environmental engineering, and wastewater treatment modelling in particular, and to use proven reliable and consistent simulation models. © 2011 Elsevier Ltd.
Van Doorsselaere J.,Ghent University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013
We discuss properties of the electroweak vacuum as a function of an external magnetic field. The interest in these properties arises due to possible existence of the electromagnetically superconducting phase of QCD in the background of a sufficiently strong magnetic field. In the electroweak theory, a superconducting vacuum exists for a well defined range of magnetic background fields, and the interest of the current paper is the behavior near the upper critical magnetic field. We determine this critical field and calculate the vacuum condensates to leading order. © 2013 American Physical Society.
Rondou P.,Ghent University
Cellular and molecular life sciences : CMLS | Year: 2010
Dopamine is an important neurotransmitter that regulates several key functions in the brain, such as motor output, motivation and reward, learning and memory, and endocrine regulation. Dopamine does not mediate fast synaptic transmission, but rather modulates it by triggering slow-acting effects through the activation of dopamine receptors, which belong to the G-protein-coupled receptor superfamily. Besides activating different effectors through G-protein coupling, dopamine receptors also signal through interaction with a variety of proteins, collectively termed dopamine receptor-interacting proteins. We focus on the dopamine D4 receptor, which contains an important polymorphism in its third intracellular loop. This polymorphism has been the subject of numerous studies investigating links with several brain disorders, such as attention-deficit hyperactivity disorder and schizophrenia. We provide an overview of the structure, signalling properties and regulation of dopamine D4 receptors, and briefly discuss their physiological and pathophysiological role in the brain.
Vriet C.,BASF |
Russinova E.,VIB |
Russinova E.,Ghent University |
Plant Cell | Year: 2012
Plant sterols and steroid hormones, the brassinosteroids (BRs), are compounds that exert a wide range of biological activities. They are essential for plant growth, reproduction, and responses to various abiotic and biotic stresses. Given the importance of sterols and BRs in these processes, engineering their biosynthetic and signaling pathways offers exciting potentials for enhancing crop yield. In this review, we focus on how alterations in components of sterol and BR metabolism and signaling or application of exogenous steroids and steroid inhibitors affect traits of agronomic importance. We also discuss areas for future research and identify the fine-tuning modulation of endogenous BR content as a promising strategy for crop improvement. © 2012 American Society of Plant Biologists. All rights reserved.
Hoogenboom R.,Ghent University
Angewandte Chemie - International Edition | Year: 2012
Achieving the unachievable: Hard supramolecular materials displaying autonomous self-healing have been considered unachievable because of the mobility required to reconstitute supramolecular interactions after rupture. Now, relatively hard thermoplastic elastomers have been reported that meet these requirements. The picture shows a triblock copolymer containing soft supramolecular "self-healing" domains and hard, structure-giving domains. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Vansteelandt S.,Ghent University |
Vanderweele T.J.,Harvard University
Biometrics | Year: 2012
We define natural direct and indirect effects on the exposed. We show that these allow for effect decomposition under weaker identification conditions than population natural direct and indirect effects. When no confounders of the mediator-outcome association are affected by the exposure, identification is possible under essentially the same conditions as for controlled direct effects. Otherwise, identification is still possible with additional knowledge on a nonidentifiable selection-bias function which measures the dependence of the mediator effect on the observed exposure within confounder levels, and which evaluates to zero in a large class of realistic data-generating mechanisms. We argue that natural direct and indirect effects on the exposed are of intrinsic interest in various applications. We moreover show that they coincide with the corresponding population natural direct and indirect effects when the exposure is randomly assigned. In such settings, our results are thus also of relevance for assessing population natural direct and indirect effects in the presence of exposure-induced mediator-outcome confounding, which existing methodology has not been able to address. © 2012, The International Biometric Society.
Chernodub M.N.,French National Center for Scientific Research |
Chernodub M.N.,Ghent University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014
In a recent paper Y. Hidaka and A. Yamamoto [Phys. Rev. D 87, 094502 (2013)] claim - using both analytical and numerical approaches - that the charged ρ mesons cannot condense in the vacuum subjected to a strong magnetic field. In this Comment we point out that both the analytical and numerical results of this paper are consistent with the inhomogeneous ρ-meson condensation. Furthermore, we show that the numerical results of the paper support the presence of the expected (in quenched lattice QCD) crossover transition driven by the ρ-meson condensation. Finally, we stress that the inhomogeneous ρ-meson condensation is consistent with both Vafa-Witten and Elitzur theorems. © 2014 American Physical Society.
Beeckman D.S.,Ghent University
Current issues in molecular biology | Year: 2010
Numerous bacterial proteins exert their function outside the prokaryotic cell. To this end, both Gram-negative and Gram-positive bacteria have evolved specialized mechanisms to transport their proteins to the bacterial supernatant or host cell cytoplasm, so called secretion systems. These different strategies will be briefly discussed, followed by an in depth description of the Type III secretion system, an efficient molecular syringe assisting Gram-negative bacteria in entrance, growth and survival in eukaryotic host cells. Topics addressed include classification and role of multiple Type III secretion systems, the mechanism of protein translocation into the host cell as well as substrate recognition and chaperoning. Chlamydiales have also been found to encode a Type III secretion system and associated effector proteins. In contrast to the genetic organization in other bacteria, the encoding genes are scattered throughout the genome. To date, no structural information is available on the chlamydial Type III secretion system. We therefore propose a model of the chlamydial Type III secretion system and summarize current knowledge on the role of Type III secretion in the different stages of the chlamydial developmental cycle.
Gervais R.,Ghent University
Studies in History and Philosophy of Science Part A | Year: 2014
According to explanatory pluralism, the appropriate explanatory level is determined by pragmatic factors, and there are no general exclusion or preference rules concerning higher- or lower-level explanations. While I agree with the latter claim, I will argue that the former is in need of revision. In particular, I will argue that by distinguishing cases of two explanations being descriptions of one underlying causal process, and two explanations being descriptions of two distinct causal processes, it becomes clear that the grain size of an explanation is in fact determined by the interplay of various pragmatic and non-pragmatic factors. Within these constraints, positive guidelines can be developed to direct us to the appropriate explanatory level. This gives us the outlines for a general framework for classifying various types of relations between explanations on different levels. After making a comparison between this new framework and standard explanatory pluralism, I end by suggesting some ways in which the framework could be further developed. © 2014 Elsevier Ltd.
Van Tuyckom C.,Ghent University
Scandinavian Journal of Public Health | Year: 2011
Background: Although there is a growing agreement among researchers that the modern environment contributes to the current trend of decreasing leisure-time physical activity (LTPA), there are very few studies addressing environmental and policy correlates of LTPA within a cross-national European context. This study describes LTPA patterns across the European Union and identifies some macro-environmental factors associated with LTPA rates at a national level. Methods: Data on LTPA and indicators of the economic, physical, and policy environment were assembled from international databases for the 27 European member states. To examine the association of each of the independent macro-environmental variables and LTPA as a continuous dependent variable, bivariate linear regression models were employed. Separate analyses were done for the overall, male, and female groups. Results: With respect to LTPA, striking differences between European member states and genders were found, with higher rates in Western and Northern European countries, and among males. Statistical significant associations were observed between overall LTPA and variables from the economic (GDP, real GDP, and public expenditures on health), food (available fat, available fruit, and vegetables), urbanisation (urban population, total and new passenger cars), and policy (all governance indicators) domains. Associations for male and female LTPA were similar, except that for males available fruit and vegetables, and for females available fat and urban population were not significant. Conclusions: This exploratory study seeks to plead for the need for cross-nationally comparable LTPA data and more sophisticated research in order to understand the role of macro-economic environments, with a special focus on policy-related variables and gender-specific differences. © 2011 the Nordic Societies of Public Health.
Martens L.C.,Ghent University
European Archives of Paediatric Dentistry | Year: 2011
Aim: The aim of this introduction to this special laser issue is to describe some basic laser physics and to delineate the potential of laser-assisted dentistry in children. Review: A brief review of the available laser literature was performed within the scope of paediatric dentistry. Attention was paid to soft tissue surgery, caries prevention and diagnosis, cavity preparation, comfort of the patient, effect on bacteria, long term pulpal vitality, endodontics in primary teeth, dental traumatology and low level laser therapy. Although there is a lack of sufficient evidence taking into account the highest standards for evidence-based dentistry, it is clear that laser application in a number of different aetiologies for soft tissue surgery in children has proven to be successful. Lasers provide a refined diagnosis of caries combined with the appropriate preventive adhesive dentistry after cavity preparation. This will further lead to a new wave of micro-dentistry based on 'filling without drilling'. Conclusion: It has become clear from a review of the literature that specific laser applications in paediatric dentistry have gained increasing importance. It can be concluded that children should be considered as amongst the first patients for receiving laser-assisted dentistry.
Ellenbecker T.S.,Physiotherapy Associates Scottsdale Sports Clinic |
Cools A.,Ghent University
British Journal of Sports Medicine | Year: 2010
Rehabilitation of the patient with glenohumeral impingement requires a complete understanding of the structures involved and the underlying mechanism creating the impingement response. A detailed clinical examination and comprehensive treatment programme including specific interventions to address pain, scapular dysfunction and rotator cuff weakness are recommended. The inclusion of objective testing to quantify range of motion and both muscular strength and balance in addition to the manual orthopaedic clinical tests allows clinicians to design evidence- based rehabilitation programmes as well as measure progression and patient improvement.
Colman E.,Ghent University
BMC health services research | Year: 2012
The high mental health care consumption rates of divorced singles may constitute a heavy burden on the public health care system. This raises the question of whether their higher health care use stems from a greater need, or whether there are other factors contributing to these high consumption rates. We examine both health care use and subjective unmet need (perceiving a need for care without seeking it) because of social or emotional problems of the divorced singles, the repartnered divorcees, and the married. Moreover, we investigate how health care use and subjective unmet need relate to each other. We conduct several gender specific logistic regressions employing data from the Divorce in Flanders Survey (N men = 2884; N women = 3317). Results show that the divorced singles have more contact with professional health care providers (general practitioners, psychiatrists, and psychologists) because of social or emotional problems, and more often perceive unmet needs. The higher health care use rates and greater subjective unmet needs can largely be attributed to higher levels of depressive symptoms. Surprisingly, we find that non-frequent health care users more often perceive a subjective unmet need than frequent health care users and those who have not contacted any health care provider. The single divorced consult health care providers more often because of social or emotional problems and they also perceive unmet needs more often.
Lefever S.,Ghent University
Clinical chemistry | Year: 2013
Genome-sequencing studies have led to an immense increase in the number of known single-nucleotide polymorphisms (SNPs). Designing primers that anneal to regions devoid of SNPs has therefore become challenging. We studied the impact of one or more mismatches in primer-annealing sites on different quantitative PCR (qPCR)-related parameters, such as quantitative cycle (Cq), amplification efficiency, and reproducibility. We used synthetic templates and primers to assess the effect of mismatches at primer-annealing sites on qPCR assay performance. Reactions were performed with 5 commercially available master mixes. We studied the effects of the number, type, and position of priming mismatches on Cq value, PCR efficiency, reproducibility, and yield. The impact of mismatches was most pronounced for the number of mismatched nucleotides and for their distance from the 3' end of the primer. In addition, having ≥4 mismatches in a single primer or having 3 mismatches in one primer and 2 in the other was required to block a reaction completely. Finally, the degree of the mismatch effect was concentration independent for single mismatches, whereas concentration independence failed at higher template concentrations as the number of mismatches increased. Single mismatches located >5 bp from the 3' end have a moderate effect on qPCR amplification and can be tolerated. This finding, together with the concentration independence for single mismatches and the complete blocking of the PCR reaction for ≥4 mismatches, can help to chart mismatch behavior in qPCR reactions and increase the rate of successful primer design for sequences with a high SNP density or for homologous regions of sequence.
Derakshan N.,Birkbeck, University of London |
Koster E.H.W.,Ghent University
Behaviour Research and Therapy | Year: 2010
It is generally held that anxiety is characterized by an attentional bias for threatening information. In recent years there has been an important debate whether these biases reside at the level of attentional selection (threat detection) or attentional processing after threat detection (attentional disengagement). In a visual search task containing emotional facial expressions, eye-movements were examined before and after threat detection in high and low trait anxious individuals to further elucidate the temporal unfolding of attentional bias. Results indicated that high-anxious individuals neither showed facilitated orienting to threat nor impaired disengagement of visual attention from threat. Interestingly, the presence of threat in the visual search display was associated with increased decision times in high-anxious individuals. These results challenge some of the current views on attentional bias to threat but indicate that emotional information reduces processing efficiency in anxiety. © 2010.
Aps J.K.M.,Ghent University
Dentomaxillofacial Radiology | Year: 2010
The aim of this study was to assess general dental practitioners' knowledge of dental radiography and radiation protection in order to alert the Belgian authorities and dental professional societies. Prior to attending a postgraduate course on intraoral radiology, general dental practitioners in Flanders, Belgium, were asked to fill in a questionnaire regarding the radiological equipment and the techniques they used for intraoral radiography. The availability and type of dental panoramic equipment were also assessed. A total of 374 questionnaires were available for this study. 15% of the attendants used radiographic equipment that was more than 27 years old and 43% reported equipment that operated with a clockwork timer. 32% and 75% respectively had no idea what the kV or mA settings were on their intraoral equipment. 5% were unaware which cone geometry or geometric technique (paralleling or bisecting angle technique) they were using. 81% claimed to be using a short cone technique. 47% did not know what collimation meant, whereas 40% stated that they were using circular collimation. 38% used digital intraoral image detectors (63% were photostimulable storage phosphorplate (PSPP)), but 16% were not sure about the type of sensor they were using (PSPP or solid-state sensors). 61% also had dental panoramic equipment available, 25% of which was digital (10% charge coupled device (CCD) and 15% PSPP). These results clearly indicate the need for continued education on this subject. The latter is an important signal to Belgian authorities and dental professional societies. © 2010 The British Institute of Radiology.
Hamalainen R.,University of Jyvaskyla |
de Wever B.,Ghent University
International Journal of Computer-Supported Collaborative Learning | Year: 2013
This study focuses on vocational education teachers' instructional activities in a new technology-enhanced learning (TEL) setting. A content analysis is applied to investigate teachers' and students' interactions in a 3D game context. The findings illustrate that when teachers' and students' interactions are mediated by a game, teachers seem to apply different discussion activities to empower vocational learning than they do in traditional classroom settings. Additionally, the present study shows that teachers spontaneously develop new ways of supporting vocational learning processes. In more detail, two main types of instructional activities were identified: a "knowledge-providing" approach and a "joint problem-solving" approach. Additionally, findings illustrate how teachers using different types of instructional approaches are followed up with different processes by students. The article is concluded with a general discussion of the emerging challenges regarding the technological and pedagogical development of vocational education and teachers' instructional activities in new TEL settings based on a more long-term design-based research project (ongoing since 2004). © 2013 International Society of the Learning Sciences, Inc. and Springer Science+Business Media New York.
Neutens T.,Ghent University
Journal of Transport Geography | Year: 2015
Research at the confluence of accessibility, equity and health is flourishing. And yet, there is only slow and modest progress in terms of improving the spatial and temporal accuracy of measuring accessibility and equity of accessibility to health care services. This paper critically reviews the latest methodological and empirical research developments and trends in this area through a transport geography lens. More specifically, this paper discusses recent accomplishments in terms of modeling accessibility and provides a systematic and comprehensive literature review of their application in empirical studies of health care delivery. Based on this literature review a research agenda is put forward, identifying knowledge gaps that transport researchers can help to fill. These knowledge gaps pertain to the need for more spatially disaggregated, individualized and temporally-aware accessibility metrics, more sophisticated geocomputational tools to operationalize such metrics and improved measurement of equity considerations in empirical research. © 2015 Elsevier Ltd.
De Graeve K.,Ghent University
Bioethics | Year: 2010
The concept of 'intimate citizenship' stresses the right of people to choose how they organize their personal lives and claim identities. Support and interest groups are seen as playing an important role in the pursuit of recognition for these intimate choices, by elaborating visible and positive cultures that invade broader public spheres. Most studies on intimate citizenship take into consideration the exclusions these groups encounter when negotiating their differences with society at large. However, much less attention is paid to the ways in which these groups internalize the surrounding ideologies, identity categories and hierarchies that pervade society and constrain their recognition as full citizens. In contrast, this paper aims to emphasize the reproduction of otherness within alternative spheres of life, and to reveal the ambiguities and complexities involved in their dialectic relationship with society at large. To address this issue, the paper focuses on the role that 'adoption cultures' of Flemish adoptive parents with children from Ethiopia play in the pursuit of being recognized as 'proper' families and full citizens. The ethnographic research among adoptive parents and adoption professionals shows a defensive discourse and action that aims at empowering against potential problems, as well as a tendency to other the adoptive child by pathologizing its non-normativity. By showing the strong embeddedness of adoptive families' practices of familial and cultural construction in larger cultural frames of selfing and othering, characterized by biologism and nativism, one begins to understand the limits of their capacity to realize full citizenship. © 2010 Blackwell Publishing Ltd.
De Reu J.,Ghent University
Radiocarbon | Year: 2014
To formulate a solid chronology of the northwest Belgian Bronze Age barrow phenomenon, a critical review of the available radiocarbon dates was necessary. The resulting 14C chronology of the barrows was compared with the 14C chronologies of the Late Neolithic Bell Beaker graves, the Bronze Age metalwork depositions, the evidence of barrow reuse, and the Bronze Age longhouses. This research revealed interesting patterns concerning the appearance and disappearance of the barrow phenomenon. The earliest 14C-dated barrows are dated during the Late Neolithic and coincide with the presence of the Bell Beaker culture in the region. The peak of the barrow-building practice occurred between 1700 and 1500/1400 cal BC, a period of flourishing trade networks in the regions along the North Sea basin. The period around 1500 cal BC is characterized by the disappearance of barrow-building practices and the sudden appearance of ritual deposi-tional practices, reflecting changes in society. © 2014 by the Arizona Board of Regents on behalf of the University of Arizona.
Van Damme E.J.M.,Ghent University
Methods in Molecular Biology | Year: 2011
Glycosylation has been recognized as one of the most important modifications on proteins. The interactions between proteins and glycans are known to play an important role in many biological processes. Lectins are carbohydrate-binding proteins that can specifically interact with and select for carbohydrate structures. The technique of lectin affinity chromatography takes advantage of this specific interaction and enables the selection and purification of glycoproteins with carbohydrate structures complementary to the lectin-binding site. Depending on the carbohydrate specificity of the lectin glycoprotein fractions enriched for example, high mannose or complex N-glycans or O-glycans can be obtained. Afterward both the protein part and the glycan part can be analyzed in more detail allowing the identification of the interacting partners and the type of glycans involved. © Springer Science+Business Media, LLC 2011.
Steendam H.,Ghent University
IEEE Transactions on Signal Processing | Year: 2013
Unique-word (UW) OFDM is a new multicarrier technique that was recently proposed in [M. Huemer, C. Hofbauer, and J. B. Huber, 'The Potential of Unique Words in OFDM, Proc. InOWo, Hamburg, Germany, Sep. 2010, pp. 140-144]. In this technique, the guard interval that contains a priori known samples is part of the FFT interval. To be able to construct the UW-OFDM signal, some carriers must be sacrificed to transmit redundant information - these carriers are called the redundant carriers. It turns out that the average redundant energy needed strongly depends on the positions of the redundant carriers. In this paper, we look for the redundant carrier placement that minimizes the average redundant energy. However, this optimization is a NP-hard problem. Therefore, we reformulate the optimization problem and implement a branch and bound (B&B) algorithm to find the optimum. The results of the B&B search algorithm are compared to a theoretical lower bound, and with the results for two low cost redundant carrier placements, i.e., the quasi-uniform (QU) distribution [H. Steendam, 'The Quasi-Uniform Redundant Carrier Placement for UW-OFDM,' Vehicular Technology Conf., Fall 2012, Quebec, Canada, Sep. 2012], for the case where no guard bands are present, and the maximum distance (MD) distribution, in case forbidden guard bands are present. We show in this paper that when the full band is available for redundant carriers, both the redundant carrier placement found with the B&B algorithm and the QU distribution result in a redundant energy that is very close to the theoretical lower bound. Although the B&B slightly outperforms the QU distribution, this implies that the QU distribution is a good low cost solution to the redundant carrier placement problem in the case of no guard bands. However, when there are forbidden guard bands in which the redundant carriers cannot be placed, the QU distribution can no longer be used. In that case, the results of the B&B algorithm are compared to that of the MD distribution. We show in this paper that the proposed B&B algorithm outperforms the MD distribution in the sense that it needs noticeably lower redundant energy. © 1991-2012 IEEE.
Maes W.H.,Ghent University |
Verbist B.,Catholic University of Leuven
Renewable and Sustainable Energy Reviews | Year: 2012
Although 40% of the global population relies on traditional biomass use, mainly firewood and charcoal, for cooking, traditional biomass has received very little attention in the current biomass debate, because of its considered primitive and unsustainable nature. In this review, we discuss how the sustainability of household cooking in developing countries can be improved. Indoor air pollution due to incomplete combustion of traditional biomass causes the death of 1.45 million people every year, mainly of women and children, who also carry the heavy burden of fuelwood collection. In addition, charcoal production and combustion is responsible for very high greenhouse gas emissions per unit of energy. On the other hand, fuelwood production and trade is of vital importance for local economies and serves as safety net for the poorest people. Moreover, fuelwood collection is not a driver of deforestation and global fuelwood shortage will not occur, despite local problems of fuelwood provision. There are two distinct policy alternatives to increase the sustainability of cooking in developing countries. The first option is to climb the energy ladder and to switch from solid fuels to fossil fuels (LPG or kerosene), biogas or electricity. As this largely avoids the severe health damages of traditional biomass use, this option is considered the most desirable by numerous countries and by international organizations. However, as most developing countries are far away from meeting the necessary requirements, related to infrastructure, economics and local culture, expecting a large-scale switch to liquid fuels or electricity is unrealistic. In that case, the second policy option, increasing the sustainability of the current traditional biomass system, must be considered. This can be realized by an integrated approach, in which national and regional fuelwood policies are adapted, improved systems for charcoal production are implied and improved stoves, in combination with chimneys, are distributed. © 2012 Elsevier Ltd. All right reserved.
Vander Cruyssen B.,Ghent University
Rheumatology (Oxford, England) | Year: 2010
OBJECTIVES: Although clinicians recognize hip involvement, which frequently leads to hip replacement surgery, as an important feature of AS, data on the epidemiology, nature of the disease and therapeutic strategies are scarce. We aimed to describe the epidemiology of clinical and radiological hip involvement and define the risk factors for the hip replacement surgery in AS patients. METHODS: Data from 3 datasets were merged, including 847 Belgian (ASPECT database), 1405 Spanish (REGISPONSER database) and 466 Ibero-American (RESPONDIA database) AS patients. The ASPECT and REGISPONSER database (Dataset A) are used for exploratory analysis; the RESPONDIA database (Dataset B) is used for confirmative analysis. Factors associated with hip involvement and the hip replacement surgery were analysed. RESULTS: Twenty four (REGISPONSER) to 36% (RESPONDIA) of AS patients under rheumatologist's care presented clinical hip involvement, including the 5% (Dataset A) of AS patients who needed hip replacement surgery. Patients with hip involvement had significantly worse overall Bath Ankylosing Spondylitis Functional Index (BASFI) scores compared with patients without hip involvement (mean difference = 1.6, P < 0.001) (Dataset A, confirmed in B). Corrected for disease duration, patients with early disease onset, enthesial and axial disease needed most frequently hip replacement surgery (Dataset A, confirmed in B). CONCLUSION: Hip involvement is commonly recognized by rheumatologists in AS patients, and involves about one out of the three to four patients with AS and is associated with impaired functioning reflected by higher overall BASFI scores. Early onset of disease, axial and enthesial disease are associated with the hip replacement surgery in AS.
Leliaert F.,Ghent University |
Lopez-Bautista J.M.,University of Alabama
BMC Genomics | Year: 2015
Background: Species of Bryopsidales form ecologically important components of seaweed communities worldwide. These siphonous macroalgae are composed of a single giant tubular cell containing millions of nuclei and chloroplasts, and harbor diverse bacterial communities. Little is known about the diversity of chloroplast genomes (cpDNAs) in this group, and about the possible consequences of intracellular bacteria on genome composition of the host. We present the complete cpDNAs of Bryopsis plumosa and Tydemania expeditiones, as well as a re-annotated cpDNA of B. hypnoides, which was shown to contain a higher number of genes than originally published. Chloroplast genomic data were also used to evaluate phylogenetic hypotheses in the Chlorophyta, such as monophyly of the Ulvophyceae (the class in which the order Bryopsidales is currently classified). Results: Both DNAs are circular and lack a large inverted repeat. The cpDNA of B. plumosa is 106,859 bp long and contains 115 unique genes. A 13 kb region was identified with several freestanding open reading frames (ORFs) of putative bacterial origin, including a large ORF (>8 kb) closely related to bacterial rhs-family genes. The cpDNA of T. expeditiones is 105,200 bp long and contains 125 unique genes. As in B. plumosa, several regions were identified with ORFs of possible bacterial origin, including genes involved in mobile functions (transposases, integrases, phage/plasmid DNA primases), and ORFs showing close similarity with bacterial DNA methyltransferases. The cpDNA of B. hypnoides differs from that of B. plumosa mainly in the presence of long intergenic spacers, and a large tRNA region. Chloroplast phylogenomic analyses were largely inconclusive with respect to monophyly of the Ulvophyceae, and the relationship of the Bryopsidales within the Chlorophyta. Conclusions: The cpDNAs of B. plumosa and T. expeditiones are amongst the smallest and most gene dense chloroplast genomes in the core Chlorophyta. The presence of bacterial genes, including genes typically found in mobile elements, suggest that these have been acquired through horizontal gene transfer, which may have been facilitated by the occurrence of obligate intracellular bacteria in these siphonous algae. © 2015 Leliaert and Lopez-Bautista; licensee BioMed Central.
Van Craenenbroeck K.,Ghent University
Sub-cellular biochemistry | Year: 2012
G protein-coupled receptor (GPCR) export to the plasma membrane is considered to follow the default secretory pathway. Several observations indicate that trafficking from the endoplasmic reticulum to the plasma membrane is strictly regulated and involves interactions with specific proteins, such as resident ER chaperones. These interactions help with GPCR folding, but more importantly, they ensure that only properly folded proteins proceed from the ER to the trans-golgi network. The assembly of several GPCRs into a quaternary structure is started in the ER, before cell surface delivery, and helps in the correct expression of the GPCRs. This review will mainly focus on the role of GPCR oligomerization in receptor biogenesis.
Leroux O.,National University of Ireland |
Leroux O.,Ghent University
Annals of Botany | Year: 2012
BackgroundCollenchyma has remained in the shadow of commercially exploited mechanical tissues such as wood and fibres, and therefore has received little attention since it was first described. However, collenchyma is highly dynamic, especially compared with sclerenchyma. It is the main supporting tissue of growing organs with walls thickening during and after elongation. In older organs, collenchyma may become more rigid due to changes in cell wall composition or may undergo sclerification through lignification of newly deposited cell wall material. While much is known about the systematic and organographic distribution of collenchyma, there is rather less information regarding the molecular architecture and properties of its cell walls.Scope and conclusionsThis review summarizes several aspects that have not previously been extensively discussed including the origin of the term 'collenchyma' and the history of its typology. As the cell walls of collenchyma largely determine the dynamic characteristics of this tissue, I summarize the current state of knowledge regarding their structure and molecular composition. Unfortunately, to date, detailed studies specifically focusing on collenchyma cell walls have not been undertaken. However, generating a more detailed understanding of the structural and compositional modifications associated with the transition from plastic to elastic collenchyma cell wall properties is likely to provide significant insights into how specific configurations of cell wall polymers result in specific functional properties. This approach, focusing on architecture and functional properties, is likely to provide improved clarity on the controversial definition of collenchyma. © 2012 The Author 2012. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissionsoup.com.
Verdoolaege G.,Ghent University |
Scheunders P.,University of Antwerp
Journal of Mathematical Imaging and Vision | Year: 2012
This paper concerns the geometry of the zero-mean multivariate generalized Gaussian distribution (MGGD) and the calculation of geodesic distances on the MGGD manifold. The MGGD is a suitable distribution for the modeling of multivariate (color, multispectral, vector and tensor images, etc.) image wavelet statistics. Expressions are derived for the Fisher-Rao metric for the zero-mean MGGD model. A closed-form expression is obtained for the geodesic distance on the submanifolds characterized by a fixed MGGD shape parameter. Suitable approximate solutions to the geodesic equations are presented in the case of MGGDs with varying shape parameters. An application to image texture similarity measurement in the wavelet domain is briefly discussed, comparing the performance of the geodesic distance and the Kullback-Leibler divergence. © 2011 Springer Science+Business Media, LLC.
Steendam H.,Ghent University
IEEE Wireless Communications and Networking Conference, WCNC | Year: 2012
Unique word (UW) OFDM is a new multicarrier technique that was first introduced in . In this technique, the guard interval is a part of the inverse FFT (IFFT) output, and is filled with known symbols. To be able to construct - by using an IFFT - a time domain signal containing a block of known samples, it is necessary to sacrifice a number of carriers. These carriers are called redundant carriers and the symbols modulated on these redundant carriers depend on the data to be transmitted. In this paper, we evaluate the distribution of the redundant carriers over the bandwidth. It turns out that when the positions of the redundant carriers are not carefully selected, the extra energy needed for the redundant carriers can become very large. We propose a novel algorithm for the placement of the redundant carriers that is based on a simple analytical expression, such that extensive simulations to find the optimal distribution is avoided. The proposed distribution yields essentially minimal average redundant energy. © 2012 IEEE.
Lamkanfi M.,Ghent University |
Kanneganti T.-D.,St Jude Childrens Research Hospital
Immunobiology | Year: 2012
Members of the nucleotide-binding and oligomerization domain (NOD)-like receptor (NLR) family are quickly emerging as critical regulators of innate and adaptive immune responses during microbial infection and autoimmunity. The NLR family member NLRC5 was recently proposed to function as a positive and negative regulator of antiviral immune responses. NLRC5 has also been implicated in regulation of inflammasome signaling and MHC class I transcription. Some of these functions have recently been assessed in NLRC5-deficient mice and immune cells. Here, we summarize and review the newly gained knowledge on the structure, expression profile and putative functions of NLRC5 in regulating immune responses and host defense. © 2011 Elsevier GmbH.
De Almeida Engler J.,French National Institute for Agricultural Research |
Gheysen G.,Ghent University
Molecular Plant-Microbe Interactions | Year: 2013
Plant-parasitic root-knot and cyst nematodes have acquired the ability to induce remarkable changes in host cells during the formation of feeding sites. Root-knot nematodes induce several multinucleate giant cells inside a gall whereas cyst nematodes provoke the formation of a multinucleate syncytium. Both strategies impinge on the deregulation of the cell cycle, involving a major role for endoreduplication. This review will first describe the current knowledge on the control of normal and aberrant cell cycles. Thereafter, we will focus on the role of both cell-cycle routes in the transformation process of root cells into large and highly differentiated feeding sites as induced by the phytoparasitic root-knot and cyst nematodes. © 2013 The American Phytopathological Society.
De Coninck T.,Ghent University
The American journal of sports medicine | Year: 2013
Little is known about radial displacement (RD) of polyurethane (PU) scaffolds, intended for partial meniscus defect substitution; no data are available on whether rim thickness influences RD and whether RD correlates with clinical outcome scores. The meniscus is not extruded preoperatively, but RD occurs after scaffold implantation. A thicker rim will limit RD, and there is no correlation between RD and clinical outcome. Case series; Level of evidence, 4. Twenty-six patients were implanted with a PU scaffold (8 lateral, 18 medial). Radial displacement (mm) was evaluated on magnetic resonance images preoperatively and at 3 months, 1 year, and 2 years postoperatively. At each time point, it was determined whether a correlation existed between the rim and RD. Clinical outcome was determined using a visual analog scale (VAS) for pain as well as the Lysholm knee scoring scale, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) score. Radial displacement of lateral scaffolds was not significantly different (P = .178) either preoperatively (mean ± SD, 3.42 ± 0.99 mm) or at 3 months (4.82 ± 0.59 mm), 1 year (4.55 ± 0.87 mm), or 2 years postoperatively (4.10 ± 0.93 mm). No correlation was observed between the rim and lateral RD at all time points. Medial scaffold RD increased significantly (P < .001) from preoperative values (2.17 ± 0.84 mm) to those at 3 months (4.25 ± 0.89 mm), 1 year (4.43 ± 1.01 mm), and 2 years postoperatively (4.41 ± 0.96 mm). A strong negative correlation between medial RD and the rim was observed at all time points. There was no significant correlation between clinical outcome scores and RD, either preoperatively or postoperatively. This study demonstrated that limited medial meniscal RD was present preoperatively but increased by 2 mm after scaffold implantation. Lateral RD was also present preoperatively but did not increase after scaffold implantation. Importantly, a strong negative correlation was found between the rim and postoperative medial RD; a thicker rim limited RD. However, in the lateral compartment, rim thickness did not correlate with RD because RD was already strongly present preoperatively. Finally, no correlations were observed between scaffold RD and clinical outcome scores, either preoperatively or postoperatively.
De Geyter N.,Ghent University
Surface and Coatings Technology | Year: 2013
In this work, polylactic acid (PLA) surfaces are exposed to a medium pressure dielectric barrier discharge (DBD). PLA surface transformations are realized with DBDs in different atmospheres (air, helium, helium/air mixtures) and are compared to study the influence of discharge atmosphere on the PLA surface modification. A first part of the paper is dedicated to the discharge characterization using current-voltage waveforms and optical emission spectra, while the second part containing contact angle and XPS results focusses on the surface modification effect. Results show that the discharge gas significantly influences the final PLA surface composition: the helium DBD leads to a high nitrogen incorporation on the PLA surface, while the air discharge results in a high oxygen incorporation. Moreover, the addition of a very small amount of air in helium is sufficient to completely change the chemistry on the PLA surface: nitrogen incorporation is hindered by the presence of oxygen containing plasma species, thereby proving the extreme reactivity of these plasma species. When more oxygen is added to the surface than nitrogen, the minimum contact angle value is limited to 59°. However, when the surface chemistry is essentially related to nitrogen grafting, the PLA wettability becomes higher (lowest contact angle value equal to 36°). © 2012 Elsevier B.V.
De Schoenmaker S.,Ghent University
Tobacco control | Year: 2013
To examine whether the nationwide smoking ban, imposed in 2007, had an impact on the profitability of Belgian restaurants. Objective financial reporting data on 1613 restaurants were analysed with return on assets as the outcome measure. The data were collected from the Belfirst database and cover the period 2004-2009. To assess the impact of the smoking ban, a differences-in-differences estimation method was used, with bars serving as the control group. The regression model was estimated, while controlling for firm-specific characteristics and unobserved firm-level heterogeneity. The variable of interest is the interaction between the smoking ban dummy and the dummy for the treatment group. The coefficient of this variable is insignificant. The adoption of the nationwide smoking ban did not affect the profitability of Belgian restaurants.
Defoirdt T.,Ghent University
Reviews in Aquaculture | Year: 2014
Although aquaculture continues to be the fastest-growing food-producing industry worldwide, the sector faces important challenges with respect to controlling infectious diseases. Indeed, the frequent use of antibiotics, which are traditionally the most important line of defence against bacterial disease, has raised problems related to the development and spread of resistance. As a result, we currently are in a race to develop novel therapeutics that should allow us to continue controlling bacterial disease in the future. In this respect, scientific progress of the past years has allowed us to start understanding the mechanisms by which bacterial pathogens are causing disease. This knowledge in its turn opens up novel possibilities to combat infections by interfering with these mechanisms, a strategy that has been termed antivirulence therapy. In this review, the current knowledge with respect to pathogenicity mechanisms of bacterial aquaculture pathogens is discussed, including adhesion mechanisms, production of extracellular polysaccharides and biofilm formation, production of lytic enzymes (e.g. haemolysins and proteases), mechanisms of iron acquisition, secretion systems and regulatory mechanisms such as quorum sensing and host-pathogen signalling with catecholamine stress hormones. Furthermore, an overview is given of the first steps towards antivirulence therapy for aquaculture, with a focus on quorum sensing disruption as a proof of concept. © 2013 Wiley Publishing Asia Pty Ltd.
Verstraelen H.,Ghent University |
Swidsinski A.,University Tsmedizin Berlin
Current Opinion in Infectious Diseases | Year: 2013
Purpose of Review: Recent evidence supports the view that bacterial vaginosis presents as a polymicrobial biofilm infection. This has far-reaching implications for the pathogenesis, epidemiology, diagnosis and treatment of bacterial vaginosis. Recent Findings: Gardnerella vaginalis is presumably the first species to adhere to the vaginal epithelium and then becomes the scaffolding to which other species adhere. Not all G. vaginalis strains do form biofilms: G. vaginalis can be present in the vagina in a planktonic or in a biofilm mode of growth. The presence of planktonic (dispersed) or biofilm-associated (cohesive) G. vaginalis can be reliably shown in urine sediments in both women and men, and there is an absolute concordance in the carriage of biofilm-associated (cohesive) G. vaginalis between women with bacterial vaginosis and their partners. In-vitro data suggest that selected probiotic lactobacilli might be an effective means to conquer the biofilm. Summary: Future epidemiological research may benefit from biofilm-based urine diagnosis of bacterial vaginosis to a significant extent. The search for novel therapeutic agents can now be more directed towards the biofilm-breaking agents, but is at present hampered by the lack of a proper in-vitro model of the bacterial vaginosis biofilm. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Gryson N.,Ghent University
Analytical and Bioanalytical Chemistry | Year: 2010
The applicability of a DNA-based method for GMO detection and quantification depends on the quality and quantity of the DNA. Important food-processing conditions, for example temperature and pH, may lead to degradation of the DNA, rendering PCR analysis impossible or GMO quantification unreliable. This review discusses the effect of several food processes on DNA degradation and subsequent GMO detection and quantification. The data show that, although many of these processes do indeed lead to the fragmentation of DNA, amplification of the DNA may still be possible. Length and composition of the amplicon may, however, affect the result, as also may the method of extraction used. Also, many techniques are used to describe the behaviour of DNA in food processing, which occasionally makes it difficult to compare research results. Further research should be aimed at defining ingredients in terms of their DNA quality and PCR amplification ability, and elaboration of matrix-specific certified reference materials. © 2009 Springer-Verlag.
Hakim R.S.,Howard University |
Baldwin K.,Howard University |
Smagghe G.,Ghent University
Annual Review of Entomology | Year: 2010
The insect midgut is an important site of entry for pathogens and insect control agents. This review focuses on recent information related to midgut epithelial growth, metamorphosis, and repair as a defense against pathogens. The roles of stem cell mitogens and differentiation factors are described. Included is a discussion of apoptosis and autophagy in the yellow body. Sloughing, also described, protects the midgut from virus infections and bacterial toxins through death and replacement of affected cells. The mechanisms by which the repair process reduces the effectiveness of pest control strategies are discussed. Primary tissue culture methods also are described, and their value in understanding the mechanisms by which biologically based insecticides work is discussed. © 2010 by Annual Reviews All rights reserved.
Defoirdt T.,Ghent University
Trends in Biotechnology | Year: 2016
Antivirulence therapy, disarming pathogens rather than killing them, is emerging as a novel strategy for disease control. Reporter strains expressing an easily measurable and quantifiable phenotype enable easy screening of virulence inhibitors. In this paper I propose a novel concept to exclude false positives in this type of screening. © 2016 Elsevier Ltd.
Schenk H.J.,California State University, Fullerton |
Steppe K.,Ghent University |
Jansen S.,University of Ulm
Trends in Plant Science | Year: 2015
Long-distance water transport in plants relies on a system that typically operates under negative pressure and is prone to hydraulic failure due to gas bubble formation. One primary mechanism of bubble formation takes place at nanoporous pit membranes between neighboring conduits. We argue that this process is likely to snap off nanobubbles because the local increase in liquid pressure caused by entry of air-water menisci into the complex pit membrane pores would energetically favor nanobubble formation over instant cavitation. Nanobubbles would be stabilized by surfactants and by gas supersaturation of the sap, may dissolve, fragment into smaller bubbles, or create embolisms. The hypothesis that safe and stable nanobubbles occur in plants adds a new component supporting the cohesion-tension theory. © 2015 Elsevier Ltd.
Crombez G.,Ghent University
Journal of Headache and Pain | Year: 2015
Innamorati and colleagues (Innamorati et al., J Headache Pain 16:2, 2015) validated the “stagnation scale” and proposed to use it to screen for psychopathology. I have some critical comments to consider about the theoretical and clinical value of the instrument. First, items of the scale are not specific, and may equally well measure worry, self-worth and distress. Second, questionnaires are tools to assess the experiences of patients, but not hypothesized causal processes. The scale can thus not identify patients who repress emotions. Third, the routine use of this instrument will detract clinicians from what really is at stake in patients and what may help them. © 2015, Crombez; licensee Springer.
Azermai M.,Ghent University
International psychogeriatrics / IPA | Year: 2011
Given the potential adverse effects of antipsychotics, high use in nursing homes creates concern. Our study goal was to explore the use of antipsychotics in relation to resident characteristics, and to assess the appropriateness of antipsychotic prescribing in Belgian nursing homes. Data were used from a cross-sectional study (Prescribing in Homes for the Elderly; PHEBE) conducted in 76 nursing homes in Belgium. Antipsychotics were classified into typical and atypical, using the anatomical therapeutic and chemical classification. Ten inappropriate antipsychotic prescribing indicators were selected from the updated Beers criteria (2003), Bergen District Nursing Home Study (BEDNURS) indicators, and Screening Tool of Older People's Prescriptions criteria (STOPP). The residents' mean age was 84.8 years, 78.1% of whom were female. The prevalence of antipsychotic utilization was 32.9%. Antipsychotics were mainly indicated for dementia-related agitation, and psychosis with/without dementia. Higher use of antipsychotics was found for dementia (OR: 3.27; 95% CI: 2.61-4.09), insomnia (OR: 1.38; 95% CI: 1.10-1.73), depression (OR: 1.30; 95% CI: 1.03-1.65), and age <80 years (OR: 1.79; 95% CI: 1.38-2.33). Inappropriate antipsychotic prescribing indicators scoring the highest among users were: long-term use (92.6%), use despite risk of falling (45.6%), combined use with other psychotropics (31.8%), and duplicate use (15.1%). Inappropriate prescribing was associated with depression (OR: 3.41) and insomnia (OR: 2.17). The indicator-driven analysis of antipsychotic prescribing quality revealed a need for improvement, with the main prescribing problems relating to duration and combination of therapies. Risks/benefits of off-label use need to be evaluated more consciously at the start of therapy, and at periodic re-evaluations.
Kuhn S.,Ghent University |
Kuhn S.,University College London |
Kuhn S.,Charite - Medical University of Berlin |
Gallinat J.,Charite - Medical University of Berlin
Schizophrenia Bulletin | Year: 2012
Auditory verbal hallucinations (AVHs) have a high prevalence in schizophrenic patients. An array of studies have explored the neural correlates of AVHs by means of functional neuroimaging and have associated AVHs with diverse brain regions, some of which have been shown to be involved in speech generation, speech perception, and auditory stimulus processing. We divided these studies into "state" studies comparing periods of presence and absence of AVHs within-subject and "trait" studies comparing patients experiencing AVHs with patients without AVHs or healthy controls during tasks with verbal material. We set out to test the internal consistency and possible dissociations of the neural correlates of AVHs. We used activation likelihood estimation to perform quantitative meta-analyses on brain regions reported in state and trait studies on AVHs to assess significant concordance across studies. State studies were associated with activation in bilateral inferior frontal gyrus, bilateral postcentral gyrus, and left parietal operculum. Trait studies on the other hand showed convergence of decreases in hallucinating subjects in left superior temporal gyrus, left middle temporal gyrus, anterior cingulate cortex, and left premotor cortex activity. Based on the clear dissociation of brain regions that show convergence across state in comparison to trait studies, we conclude that the state of experiencing AVHs is primarily related brain regions that have been implicated in speech production ie, Broca's area, whereas the general trait that makes humans prone to AVHs seems to be related to brain areas involved in auditory stimuli processing and speech perception, ie, auditory cortex. © 2012 The Author.
Hiddinga B.I.,University of Antwerp |
Van Meerbeeck J.P.,University of Antwerp |
Van Meerbeeck J.P.,Ghent University
Journal of Thoracic Oncology | Year: 2013
The role of surgery in the management of malignant pleural mesothelioma remains controversial. Surgical resection consists of different procedures for diagnostic or therapeutic reasons. The latter includes either an extrapleural pleuropneumonectomy (EPP) or lung-sparing operations like debulking of the parietal and visceral pleura by pleurectomy/decortication (P/D) or extended pleurectomy/decortication, in which further debulking of the diaphragm or pericardium is included. Because of the modest outcome of surgery as single-modality therapy, combinations of chemotherapy, surgery, and radiation therapy were initiated as a new treatment strategy to improve prognosis. The observations that patients treated with P/D had an equal to better outcome than those treated with EPP, and that EPP with perioperative chemotherapy was better than EPP alone, raises the issue whether performing a P/D with perioperative chemotherapy would result in a further improvement of outcome with a lower operative mortality than with EPP and perioperative chemotherapy. This is the rationale for the next European Organisation for Research and Treatment of Cancer trial exploring the feasibility of P/D with perioperative chemotherapy. Copyright © 2013 by the International Association for the Study of Lung Cancer.
Lamkanfi M.,Ghent University |
Kanneganti T.-D.,St Jude Childrens Research Hospital
International Journal of Biochemistry and Cell Biology | Year: 2010
Innate immune cells rely on pathogen recognition receptors such as the nucleotide-binding and oligomerization domain (NOD)-like receptor (NLR) family to mount an appropriate immune response against microbial threats. The NLR protein Nlrp3 senses microbial ligands, endogenous danger signals and crystalline substances in the cytosol to trigger the assembly of a large caspase-1-activating protein complex termed the Nlrp3 inflammasome. Autoproteolytic maturation of caspase-1 zymogens in the Nlrp3 inflammasome leads to maturation and extracellular release of the pro-inflammatory cytokines interleukin (IL)-1β and IL-18. Gain-of-function mutations in the NOD domain of Nlrp3 are associated with auto-inflammatory disorders characterized by skin rashes and prolonged episodes of fever. In addition, decreased Nlrp3 expression was recently linked with susceptibility to Crohn's disease in humans. In this review, we discuss recent developments on the role of the Nlrp3 inflammasome in innate immunity, its activation mechanisms and the auto-inflammatory disorders associated with deregulation of Nlrp3 inflammasome activity. © 2010 Elsevier Ltd.
Zaki M.H.,St Jude Childrens Research Hospital |
Boyd K.L.,Animal Resources Center and the Veterinary Pathology Core |
Vogel P.,Animal Resources Center and the Veterinary Pathology Core |
Kastan M.B.,St Jude Childrens Research Hospital |
And 2 more authors.
Immunity | Year: 2010
Decreased expression of the Nlrp3 protein is associated with susceptibility to Crohn's disease. However, the role of Nlrp3 in colitis has not been characterized. Nlrp3 interacts with the adaptor protein ASC to activate caspase-1 in inflammasomes, which are protein complexes responsible for the maturation and secretion of interleukin-1β (IL-1β) and IL-18. Here, we showed that mice deficient for Nlrp3 or ASC and caspase-1 were highly susceptible to dextran sodium sulfate (DSS)-induced colitis. Defective inflammasome activation led to loss of epithelial integrity, resulting in systemic dispersion of commensal bacteria, massive leukocyte infiltration, and increased chemokine production in the colon. This process was a consequence of a decrease in IL-18 in mice lacking components of the Nlrp3 inflammasome, resulting in higher mortality rates. Thus, the Nlrp3 inflammasome is critically involved in the maintenance of intestinal homeostasis and protection against colitis. © 2010 Elsevier Inc.
Focquaert F.,Ghent University
Theoretical Medicine and Bioethics | Year: 2014
What if neurofeedback or other types of neurotechnological treatment, by itself or in combination with behavioral treatment, could achieve a successful "rewiring" of the psychopath's brain? Imagine that such treatments exist and that they provide a better long-term risk-minimizing strategy compared to imprisonment. Would it be ethical to offer such treatments as a condition of probation, parole, or (early) prison release? In this paper, I argue that it can be ethical to offer effective, non-invasive neurotechnological treatments to offenders as a condition of probation, parole, or (early) prison release provided that: (1) the status quo is in no way cruel, inhuman, degrading, or in some other way wrong, (2) the treatment option is in no way cruel, inhuman, degrading, or in some other way wrong, (3) the treatment is in the best interests of the offender, and (4) the offender gives his/her informed consent. © 2014 Springer Science+Business Media Dordrecht.
Ceelen W.P.,Ghent University
Minerva Chirurgica | Year: 2013
Approximately 5% of colorectal cancer (CRC) patients will develop peritoneal carcinomatosis (PC) in the absence of systemic disease. Iconographic staging is only moderately accurate, but may be improved by diffusion weighted MR imaging. Systemic chemotherapy prolongs survival in PC patients, but is less active than in patients with hepatic metastasis. Intraperitoneal chemotherapy is based mainly on pharmacokinetic and pharmacodynamic observations. An increasing number of patients is treated with cytoreductive surgery followed by hyperthermic intraperitoneal chemoperfusion (HIPEC). Provided a complete resection can be performed, a median survival of almost three years may be achieved. The combined procedure is, however, associated with potentially significant morbidity. In patients with resected CRC at high risk of peritoneal recurrence, planned repeat surgery with "prophylactic". HIPEC has been shown to significantly reduce the risk of peritoneal recurrence. Cytoreduction and HIPEC should be a component of a multimodal approach, including neoadjuvant and adjuvant therapeutic regimens. Several questions remain, such as the specific role of HIPEC versus surgery alone, and the results of ongoing randomized trials are expected to provide important answers.
Azermai M.,Ghent University
Psychology Research and Behavior Management | Year: 2015
Dealing with the behavioral and psychological symptoms of dementia (BPSD) is often complex. Given the controversy with regard to antipsychotics for behavioral problems in people with dementia, there has been a renewed emphasis on nonpharmacological interventions, with progress in the design of the relevant studies. Potential nonpharmacological interventions for BPSD are: cognitive training/stimulation, rehabilitative care, activities of daily living, music therapy, massage/touch, physical activity, education/training of professionals, and education and psychosocial support of informal caregivers. Use of antipsychotics in the management of BPSD is controversial due to limited efficacy and the risk of serious adverse effects, but credible alternatives remain scarce. The problem of chronic use of antipsychotics in nursing homes should be tackled. Discontinuation of antipsychotic medication in older individuals with BPSD appears to be feasible. Discontinuation efforts are needed to differentiate between patients for whom antipsychotics have no added value and patients for whom the benefits outweigh the risks. © 2015 Azermai
Blot S.I.,Ghent University |
Blot S.I.,University of Queensland |
Pea F.,Institute of Clinical Pharmacology |
Pea F.,University of Udine |
Lipman J.,University of Queensland
Advanced Drug Delivery Reviews | Year: 2014
Critically ill patients are at high risk for development of life-threatening infection leading to sepsis and multiple organ failure. Adequate antimicrobial therapy is pivotal for optimizing the chances of survival. However, efficient dosing is problematic because pathophysiological changes associated with critical illness impact on pharmacokinetics of mainly hydrophilic antimicrobials. Concentrations of hydrophilic antimicrobials may be increased because of decreased renal clearance due to acute kidney injury. Alternatively, antimicrobial concentrations may be decreased because of increased volume of distribution and augmented renal clearance provoked by systemic inflammatory response syndrome, capillary leak, decreased protein binding and administration of intravenous fluids and inotropes. Often multiple conditions that may influence pharmacokinetics are present at the same time thereby excessively complicating the prediction of adequate concentrations. In general, conditions leading to underdosing are predominant. Yet, since prediction of serum concentrations remains difficult, therapeutic drug monitoring for individual fine-tuning of antimicrobial therapy seems the way forward. © 2014.
Devreese K.M.J.,Ghent University
Thrombosis Research | Year: 2012
The laboratory diagnosis of the antiphospholipid syndrome (APS) via antiphospholipid antibody (aPL) tests, including lupus anticoagulant (LAC), anti-cardiolipin (aCL), or anti-beta2 glycoprotein I (aβ2GPI) antibodies remains a challenge. Coagulation tests for LAC as well as solid phase assays for aCL and aβ2GPI have methodological shortcomings, although for LAC large progress have been made in standardization. All assays are associated with clinical APS-criteria (thrombotic and/or pregnancy complications) but with limited specificity. Besides, clinical studies demonstrating the association between the presence of aPL and thrombosis are not always well designed and result in wide ranges of odds ratio with large variation between studies. The best association between thrombotic complications and aPL is found for LAC. The association between thrombosis and aCL or aβ2GPI is at least inconsistent. The inclusion of more specific assays, such as the domain-I-β2GPI. antibodies is too premature and depends on further investigation in large clinical studies and the commercial availability. The search for new assays should proceed to identify patients with aPL with increased risk for thrombosis, preferable in large prospective studies. Meanwhile, with the current available LAC, aCL and aβ2GPI assays it is strongly recommended to make antibody profiles. Multiple positivity of tests seems clinically more relevant. The strengths and weaknesses of the current laboratory criteria for APS are discussed in view of their role in risk stratification of patients with thrombotic events. © 2012 Elsevier Ltd.
D'haese J.,Ghent University
The International journal of oral & maxillofacial implants | Year: 2013
The number of clinical reports giving detailed information on clinical outcomes with guided surgery is rather scarce despite its large-scale introduction over the last decade. The aim of this report was to determine implant survival and success in terms of peri-implant bone loss and evaluate whether smoking affects the outcome. A total of 26 cases with a partially or totally edentulous maxilla were selected for implant treatment using the Facilitate software system (Astra Tech). In totally edentulous cases, six fluoride-modified OsseoSpeed implants (Astra Tech) were inserted. Immediately after implantation, abutments were screwed onto the implants. Within 8 hours, a provisional screw-retained fiber-reinforced acrylic fixed dental prosthesis was screwed on the abutments. For the partial cases, the surgical guide rested on the remaining teeth and implants were not immediately loaded. In total 13 out of 114 implants were lost within 12 months after surgery, resulting in 88.6% survival at 1 year. Twelve of those failures occurred in smokers, leading to 69.2% implant survival compared to 98.7% in nonsmokers. Implants were lost in 7 out of 26 (26.9%) patients; only 1 out of 17 nonsmokers (5.9%) compared to 6 out of 9 (66.7%) smokers lost one or more implants. In total, 38.5% of the subjects with a full immediately loaded fixed dental prosthesis experienced implant failures compared with 15.4% of the partially delayed loaded cases. The overall mean bone loss based on all implants was 0.47 mm (SD, 0.94). Mean bone loss was 0.36 mm for nonsmokers and 0.62 mm for smokers. On the basis of the current case control study, it is tempting to suggest that smoking is an exclusion factor when placing implants using stereolithographic guided surgery in conjunction with immediate loading. There is still not enough scientific evidence to show if this method is as safe and predictable as the traditional method.
Vereecken C.,Ghent University
Public health nutrition | Year: 2010
To identify the correlates of the home food environment (parents' intake, availability and food-related parenting practices) at the age of 10 years with dietary patterns during childhood and in adolescence. Primary-school children of fifty-nine Flemish elementary schools completed a questionnaire at school in 2002. Four years later they completed a questionnaire by e-mail or mail at home. Their parents completed a questionnaire on food-related parenting practices at baseline. Longitudinal study. The analyses included 609 matched questionnaires. Multi-level regression analyses were used to identify baseline parenting practices (pressure, reward, negotiation, catering on demand, permissiveness, verbal praise, avoiding negative modelling, availability of healthy/unhealthy food items and mothers' fruit and vegetable (F&V) and excess scores) associated with children's dietary patterns (F&V and excess scores). Mother's F&V score was a significant positive independent predictor for children's F&V score at baseline and follow-up, whereas availability of unhealthy foods was significantly negatively associated with both scores. Negotiation was positively associated with children's follow-up score of F&V, while permissiveness was positively associated with children's follow-up excess score. Availability of unhealthy foods and mother's excess score were positively related to children's excess score at baseline and follow-up. Parental intake and restricting the availability of unhealthy foods not only appeared to have a consistent impact on children's and adolescents' diets, but also negotiating and less permissive food-related parenting practices may improve adolescents' diets.
Ainley V.,Royal Holloway, University of London |
Brass M.,Ghent University |
Tsakiris M.,Royal Holloway, University of London
Neuropsychologia | Year: 2014
'Interoceptive awareness', defined as the individual's awareness of internal body signals, modulates self/other distinction under conditions of multisensory integration. We examined here, for the first time, the potential impact of interoceptive awareness on self/other distinction in the motor domain. In automatic imitation, inhibition of imitation is an index of an individual's success in distinguishing internally generated motor representations from those triggered by observing another person's action. This is measured by the 'congruency effect', which is the difference between mean reaction times when the observed action is 'incongruent' with the required action and when it is 'congruent'. The present study compared the congruency effect in a typical finger lifting paradigm, with interoceptive awareness measured by heartbeat perception. Contrary to expectation, interoceptive awareness was positively correlated with the congruency effect and this effect depended on mean reaction times in the incongruent condition, indicating that good heartbeat perceivers had more difficulty inhibiting the tendency to imitate. Potentially, high interoceptive awareness involves stronger interoceptive representations of the consequences of an action, implying higher empathy, greater motor reactivity in response to observed action and hence a greater tendency to imitate. Our results may also tentatively be explained within a predictive coding account of interoception. © 2014 Elsevier Ltd.
De Sutter A.I.,Ghent University
Cochrane database of systematic reviews (Online) | Year: 2012
Although combination formulas containing antihistamines, decongestants and/or analgesics are sold over-the-counter (OTC) in large quantities for the common cold, the evidence of effectiveness is limited. To assess the effectiveness of antihistamine-decongestant-analgesic combinations in reducing the duration and alleviating the symptoms of the common cold in adults and children. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4), which contains the Cochrane Acute Respiratory Infections Group's Specialised Register, OLDMEDLINE (1953 to 1965), MEDLINE (1966 to November Week 3, 2011) and EMBASE (1990 to December 2011). Randomised controlled trials (RCTs) investigating the effectiveness of antihistamine-decongestant-analgesic combinations compared with placebo, other active treatment (excluding antibiotics) or no treatment in children and adults with the common cold. Two review authors independently extracted and summarised data on general recovery, nasal obstruction, rhinorrhoea, sneezing, cough and side effects. We categorised the trials according to the active ingredients. We included 27 trials (5117 participants) of common cold treatments. Fourteen trials studied antihistamine-decongestant combinations; two antihistamine-analgesic; six analgesic-decongestant; and five antihistamine-analgesic-decongestant combinations. In 21 trials the control intervention was placebo and in six trials an active substance. Reporting of methods in most trials was poor and there were large differences in design, participants, interventions and outcomes. Pooling was only possible for a limited number of studies and outcomes.Antihistamine-decongestant: 12 trials. Eight trials report on global effectiveness, six could be pooled; n = 309 on active treatment, n = 312 placebo) the odds ratio (OR) of treatment failure was 0.27 (95% confidence interval (CI) 0.15 to 0.50); the number needed to treat for an additional beneficial outcome (NNTB) was four (95% CI 3 to 5.6). On the final evaluation day 41% of participants in the placebo group had a favourable response compared to 66% on active treatment. Of the two trials that were not included in the pooling, one showed some global effect, the other showed no effect.Antihistamine-analgesic: three trials. Two reported on global effectiveness, data from one study was presented. (n = 290 on active treatment, n = 292 ascorbic acid). The OR of treatment failure was 0.33 (95% CI 0.23 to 0.46) and the NNTB was 6.67 (95% CI 4.76 to 12.5). After six days of treatment 43% were cured in the control group and 70% in the active treatment group. The second study also showed an effect in favour of active treatment.Analgesic-decongestant: six trials. One trial reported on global effectiveness: 73% benefited compared with 52% in the control group (paracetamol) (OR 0.28, 95% CI 0.15 to 0.52).Antihistamine-analgesic-decongestant: Five trials. Four trials reported on global effectiveness, two could be pooled: global effect reported (less than one severity point on a four or five-point scale) with active treatment (52%) and placebo (34%); the OR of treatment failure was 0.47 (95% CI 0.33 to 0.67) and the NNTB was 5.6 (95% CI 3.8 to 10.2). Two other trials found no beneficial effect. Two other studies did not show any effect.Two studies with antihistamine-decongestant (113 children) could not be pooled. There was no significant effect of the active treatment.Adverse effects: the combination of antihistamine-decongestant had more adverse effects than the control intervention but the difference was not significant: 157/810 (19%) versus 60/477 (13%) participants suffered one or more adverse effects (OR 1.58, 95% CI 0.78 to 3.21). Analgesic-decongestant combinations had significantly more adverse effects than control (OR 1.71, 95% CI 1.23 to 2.37); the number needed to treat for an additional harmful outcome (NNTH) was 14. None of the other two combinations caused significantly more adverse effects. Antihistamine-analgesic: 11/90 with combination suffered one or more adverse effects (12%) versus 9/91 (10%) with control (OR 1.27, 95% CI 0.50 to 3.23). Antihistamine-analgesic-decongestant: in one study 5/224 (2%) suffered adverse effects with active treatment versus 9/208 (4%) with placebo. Two other trials reported no differences between treatment groups but numbers were not reported. Current evidence suggests that antihistamine-analgesic-decongestant combinations have some general benefit in adults and older children. These benefits must be weighed against the risk of adverse effects. There is no evidence of effectiveness in young children.
Giraud O.,University Of Toulouse Ups |
Giraud O.,French National Center for Scientific Research |
Giraud O.,University Paris - Sud |
Thas K.,Ghent University
Reviews of Modern Physics | Year: 2010
In a celebrated paper "Can one hear the shape of a drum?" M. Kac [Am. Math. Monthly 73, 1 (1966)]10.2307/2313748 asked his famous question about the existence of nonisometric billiards having the same spectrum of the Laplacian. This question was eventually answered positively in 1992 by the construction of noncongruent planar isospectral pairs. This review highlights mathematical and physical aspects of isospectrality. © 2010 The American Physical Society.
Coghill D.,University of Dundee |
Sonuga-Barke E.J.S.,University of Southampton |
Sonuga-Barke E.J.S.,Ghent University
Journal of Child Psychology and Psychiatry and Allied Disciplines | Year: 2012
The question of whether child and adolescent mental disorders are best classified using dimensional or categorical approaches is a contentious one that has equally profound implications for clinical practice and scientific enquiry. Here, we explore this issue in the context of the forth coming publication of the DSM-5 and ICD-11 approaches to classification and diagnosis and in the light of recent empirical studies. First, we provide an overview of current category-based systems and dimensional alternatives. Second, we distinguish the various strands of meaning and levels of analysis implied when we talk about categories and dimensions of mental disorder - distinguishing practical clinical necessity, formal diagnostic systems, meta-theoretical beliefs and empirical reality. Third, we introduce the different statistical techniques developed to identify disorder dimensions and categories in childhood populations and to test between categorical and dimensional models. Fourth, we summarise the empirical evidence from recent taxometric studies in favour of the 'taxonomic hypothesis' that mental disorder categories reflect discrete entities with putative specific causes. Finally, we explore the implications of these findings for clinical practice and science. © 2012 The Authors. Journal of Child Psychology and Psychiatry © 2012 Association for Child and Adolescent Mental Health.
De Backer G.,Ghent University
European journal of preventive cardiology | Year: 2012
While cardiovascular disease and certain other conditions are considered to confer a high or very high risk of cardiovascular events, the asymptomatic population can be subdivided in different categories of total CV risk using risk models; this allows the clinician to adapt the intensity of preventive strategies accordingly. Risk models, such as that based on the US Framingham Study and the SCORE model, based on European cohorts, estimate risk according to the presence of risk factors, including age, gender, smoking habits, systolic blood pressure, and cholesterol levels. However, estimation of an individual's cardiovascular risk remains approximate, and whether new biomarkers of risk will improve risk assessment is a key question. Several novel cardiovascular risk markers have been suggested, including lipid, inflammatory, thrombotic, and genetic biomarkers. Demonstrating that a novel biomarker is predictive of cardiovascular disease is, by itself, insufficient proof that it adds incremental value to existing risk estimation models. The Net Reclassification Improvement index provides an indication of the ability of a novel marker to improve risk estimation by classifying individuals to a more correct category. In addition, new risk models may be calibrated by measuring how closely predicted outcomes agree with actual outcomes. Traditional cardiovascular risk factors explain most of an individual's risk. Consequently, the addition of new risk factors to existing models has provided disappointingly small effects overall. However, there addition to conventional risk estimation may be useful in correctly reclassifying individuals at intermediate risk as above or below a chosen intervention threshold.
Dudal D.,Ghent University |
Guimaraes M.S.,State University of Rio de Janeiro |
Sorella S.P.,State University of Rio de Janeiro
Physical Review Letters | Year: 2011
We set up an infrared-based moment problem to obtain estimates of the masses of the scalar, pseudoscalar, and tensor glueballs in Euclidean Yang-Mills theories using the refined Gribov-Zwanziger (RGZ) version of the Landau gauge, which takes into account nonperturbative physics related to gauge copies. Employing lattice input for the mass scales of the RGZ gluon propagator, the lowest order moment problem approximation gives the values m0++1. 96GeV, m2++2.04GeV, and m0-+2.19GeV in the SU(3) case, all within a 20% range of the corresponding lattice values. We also recover the mass hierarchy m0++
De Regge M.,Ghent University
Acta clinica Belgica | Year: 2012
Automated external defibrillators (AEDs) have shown to improve survival after cardiopulmonary arrest (CPA) in many, but not all clinical settings. A recent study reported that the use of AEDs in-hospital did not improve survival. The current retrospective study reports the results of an in-hospital AED programme in a university hospital, and focuses on the quality of AED use. At Ghent University Hospital 30 AEDs were placed in non-monitored hospital wards and outpatient clinics treating patients with non-cardiac problems. Nurses were trained to use these devices. From November 2006 until March 2011, the AEDs were used in 23 of 39 CPA cases, in only one patient the presenting heart rhythm was ventricular fibrillation and this patient survived. Pulseless electrical activity was present in 14 patients (four survived) and asystole in eight patients (one survived). AEDs were attached to eight patients without CPA, and in 16 patients with CPA AED was not used. The quality of AED use was often suboptimal as illustrated by external artifacts during the first rhythm analysis by the AED in 30% (7/23) and more than 20 seconds delay before restart of chest compressions after the AED rhythm analysis in 50% (9/18). The literature data, supported by our results, indicate that in-hospital AED programmes are unlikely to improve survival after CPA. Moreover, their use is often suboptimal. Therefore, if AEDs are introduced in a hospital, initial training, frequent retraining and close follow-up are essential.
Hoste E.A.,Ghent University
Critical care (London, England) | Year: 2012
Acute kidney injury (AKI) in ICU patients is typically associated with other severe conditions that require special attention when renal replacement therapy (RRT) is performed. RRT includes a wide range of techniques, each with specific characteristics and implications for use in ICU patients. In the present review we discuss a wide range of conditions that can occur in ICU patients who have AKI, and the implications this has for RRT. Patients at increased risk for bleeding should be treated without anticoagulation or with regional citrate anticoagulation. In patients who are haemodynamically unstable, continuous therapies are most often employed. These therapies allow slow removal of volume and guarantee a stable blood pH. In patients with cerebral oedema, continuous therapy is recommended in order to prevent decreased cerebral blood flow, which will lead to cerebral ischemia. Continuous therapy will also prevent sudden change in serum osmolality with aggravation of cerebral oedema. Patients with hyponatraemia, as in liver failure or decompensated heart failure, require extra attention because a rapid increase of serum sodium concentration can lead to irreversible brain damage through osmotic myelinolysis. Finally, in patients with severe lactic acidosis, RRT can be used as a bridging therapy, awaiting correction of the underlying cause. Especially in ICU patients who have severe AKI, treatment with RRT requires balancing the pros and cons of different options and modalities. Exact and specific guidelines for RRT in these patients are not available for most clinical situations. In the present article we provide an update on the existing evidence.
De Hert S.,Ghent University
Best Practice and Research: Clinical Anaesthesiology | Year: 2012
Homeostasis of hemodynamics refers to the regulation of the blood circulation to meet the demands of the different organ and tissue systems. This homeostasis involves an intimate interaction between peripheral metabolic needs, vascular adaptations to meet these needs and cardiac adaptation to provide the driving force to circulate the blood. The three variables that reflect the homeostasis of cardiovascular regulation are mean systemic arterial pressure, cardiac output and total systemic vascular resistance in the circulation. Regulation of the blood circulation depends on a static component, based on the physical properties of the different vessels and the characteristics of the fluid going through these vessels. Superimposed on this static regulation, is the dynamic regulation which is based on local control systems and the controls systems that adjust hemodynamic status to meet the needs of the body as a whole. This global circulation throughout the body is regulated by hormonal and neural control systems. All these systems closely interact to maintain blood pressure between the normal levels. © 2012 Published by Elsevier Ltd.
Hendrix A.,Ghent University |
Hume A.N.,Queens Medical Center
International Journal of Developmental Biology | Year: 2011
Exosomes are 40-100 nm intraluminal vesicles that are released by cells upon fusion of multivesicular endosomes (MVEs) with the plasma membrane. The Rab family of small GTPases, including Rab27A and Rab27B, control different steps of exosome release, including transport of MVEs and docking at the plasma membrane. Exosomes are long range message particles that mediate communication between cells in physiological conditions such as mammary gland development and lactation, but also in pathology such as breast cancer. Metastasis is the culmination of cancer progression and involves a complex interaction with the local and distant environment. Exosome messaging contributes to tumor environment interactions such as immune escape, thrombosis and myofibroblast differentiation, thereby modulating metastatic niche preparation. © 2011 UBC Press.
Fodor J.,Obuda University |
De Baets B.,Ghent University
Fuzzy Sets and Systems | Year: 2012
We study uninorms of which both the underlying t-norm and underlying t-conorm are strict. Such uninorms are the only candidates for being representable by an additive generator. We prove that the representability of such a uninorm depends solely on its value at a single arbitrary point in the 'remaining' open part of the unit square. More explicitly, such a uninorm turns out to be representable if and only if this single value is located strictly between the minimum and the maximum of the corresponding arguments. If this single value coincides with one of these bounds, then the value of the uninorm at any point in the 'remaining' open part is determined by the same bound. © 2011 Published by Elsevier B.V.
Rosseel Y.,Ghent University
Journal of Statistical Software | Year: 2012
Structural equation modeling (SEM) is a vast field and widely used by many applied researchers in the social and behavioral sciences. Over the years, many software packages for structural equation modeling have been developed, both free and commercial. However, perhaps the best state-of-the-art software packages in this field are still closed- source and/or commercial. The R package lavaan has been developed to provide applied researchers, teachers, and statisticians, a free, fully open-source, but commercial-quality package for latent variable modeling. This paper explains the aims behind the development of the package, gives an overview of its most important features, and provides some examples to illustrate how lavaan works in practice.
Van Renterghem T.,Ghent University
Ecological Engineering | Year: 2014
This paper discusses that a non-deep tree belt along a road can be an interesting solution to achieve road traffic noise reduction. Noise shielding is mainly obtained as a combination of multiple scattering in the tree trunk layer and due to the presence of an acoustically soft soil. A large dataset of full-wave and highly detailed numerical simulations, based as much as possible on measured input data, shows that high biomass density should be strived for as a general rule. This conflicts, however, with practical limitations regarding access to light, nutrients and water for the trees. Some interesting approaches have been identified to relax the need for high biomass density, without affecting noise shielding to an important extent. Rectangular planting schemes, where the spacing orthogonal to the road can be increased, omitting full rows parallel to the road length axis, and thinning inside the belt are examples of such measures. It is discussed that the specific choice of a planting scheme could make a tree belt along a road an efficient noise reducing measure or not. © 2014 Elsevier B.V.
Vanakker O.M.,Ghent University
Laboratory investigation; a journal of technical methods and pathology | Year: 2010
Soft-tissue mineralization is a tightly regulated process relying on the activity of systemic and tissue-specific inhibitors and promoters of calcium precipitation. Many of these, such as matrix gla protein (MGP) and osteocalcin (OC), need to undergo carboxylation to become active. This post-translational modification is catalyzed by the gammaglutamyl carboxylase GGCX and requires vitamin K (VK) as an essential co-factor. Recently, we described a novel phenotype characterized by aberrant mineralization of the elastic fibers resulting from mutations in GGCX. Because of the resemblance with pseudoxanthoma elasticum (PXE), a prototype disorder of elastic fiber mineralization, it was coined the PXE-like syndrome. As mutations in GGCX negatively affect protein carboxylation, it is likely that inactive inhibitors of calcification contribute to ectopic mineralization in PXE-like syndrome. Because of the remarkable similarities with PXE, we performed a comparative study of various forms of VK-dependent proteins in serum, plasma (using ELISA), and dermal tissues (using immunohistochemistry) of PXE-like and PXE patients using innovative, conformation-specific antibodies. Furthermore, we measured VK serum concentrations (using HPLC) in PXE-like and PXE samples to evaluate the VK status. In PXE-like patients, we noted an accumulation of uncarboxylated Gla proteins, MGP, and OC in plasma, serum, and in the dermis. Serum levels of VK were normal in these patients. In PXE patients, we found similar, although not identical results for the Gla proteins in the circulation and dermal tissue. However, the VK serum concentration in PXE patients was significantly decreased compared with controls. Our findings allow us to conclude that ectopic mineralization in the PXE-like syndrome and in PXE results from a deficient protein carboxylation of VK-dependent inhibitors of calcification. Although in PXE-like patients this is due to mutations in the GGCX gene, a deficiency of the carboxylation co-factor VK is at the basis of the decreased activity of calcification inhibitors in PXE.
Van Bockstal M.,Ghent University
Virchows Archiv : an international journal of pathology | Year: 2014
This study aimed to characterize ductal carcinoma in situ (DCIS) according to human epidermal growth factor receptor 2 (HER2) amplification status and molecular subtype. In addition, we performed a detailed HER2 and CEP17 copy number analysis and we assessed the impact of recent changes in the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines on HER2 immunohistochemical (IHC) scores in DCIS. Nuclear grade, extensive comedonecrosis, stromal architecture, stromal inflammation, and progesterone receptor (PR) expression were significantly associated with HER2 amplification status. In multivariate analysis, stromal inflammation and extensive comedonecrosis were the only two features that remained significantly related to HER2 amplification status. The recent changes in ASCO/CAP guidelines resulted in significant upgrading of HER2 IHC score. Remarkably, about one in five non-amplified DCIS presented a 3+ IHC score, regardless of the scoring method. The biological significance of this phenomenon is presently unknown. After categorization according to molecular subtype, luminal A DCIS mainly presented histopathological features associated with good prognosis, whereas luminal B/HER2+ and HER2+ categories displayed a more aggressive phenotype. Overall, our results demonstrate that HER2-amplified DCIS constitute a clearly distinct subgroup which is characterized by histopathological features associated with poor prognosis. Further studies are required to elucidate the biological significance of a 3+ IHC score in non-amplified DCIS, as well as its mechanism.
Ntagiopoulos P.G.,Lyon Ortho Clinic |
Byn P.,Ghent University |
Dejour D.,Lyon Ortho Clinic
American Journal of Sports Medicine | Year: 2013
Background: Trochlear dysplasia is one of the most consistent anatomic factors that can lead to recurrent patellar dislocations. Various trochleoplasty procedures have been described to treat patellar dislocations in high-grade dysplasia by creating a new congruent trochlea. Purpose: To present the midterm efficacy and outcome of the sulcus-deepening trochleoplasty procedure in patients with recurrent patellar dislocations due to high-grade trochlear dysplasia. The clinical evaluation results, the amount of radiological correction, and the prevalence of arthritis were recorded. Study Design: Case series; Level of evidence, 4. Methods: A total of 27 skeletally mature patients (31 knees) with recurrent patellar dislocations due to high-grade trochlear dysplasia without any previous surgery were retrospectively included from September 1993 to September 2006. All patients underwent sulcus-deepening trochleoplasty combined with a bony and/or soft tissue procedure according to concomitant etiological factors to patellar dislocations: medial patellofemoral ligament reconstruction (16.1%), vastus medialis obliquus plasty (83.8%), tibial tuberosity distalization (51.6%), tibial tuberosity medialization (67.7%), and lateral retinaculum release (67.6%). Mean followup was 7 years (range, 2-9 years). Results: The mean sulcus angle decreased significantly (P < .01) from 152° ± 16° preoperatively to 141° ± 9° postoperatively, tibial tuberosity-trochlear groove distance decreased significantly (P < .001) from 19 ± 4 mm to 12 ± 5 mm, and patellar tilt decreased significantly (P < .001) from 37° ± 7° to 15° ± 8°. No recurrence was observed, and there was no case of stiffness. Apprehension signs remained positive in 19.3% of the cases, patellar tracking was normal in all cases, and the lateral patellar glide test finding was negative in 96.8%. The mean preoperative International Knee Documentation Committee (IKDC) score was 51 (range, 25-80), and the mean postoperative IKDC score was 82 (range, 40-100) (P < .001), while the mean Kujala score improved from a preoperative 59 (range, 28-81) to 87 (range, 49-100) postoperatively (P < .001). There was no radiographic evidence of patellofemoral arthritis at the latest follow-up. Conclusion: Sulcus-deepening trochleoplasty is a valid option for the primary surgical treatment of carefully selected patients with recurrent patellar dislocations with high-grade trochlear dysplasia type B and D. Concomitant etiological factors must be cautiously corrected in an associated procedure. Midterm follow-up showed satisfactory restoration of patellar stability and improvement of knee scores with no complication of subsequent arthritis. © 2013 The Author(s).
Verbrugge B.,Ghent University
Extractive Industries and Society | Year: 2014
In line with trends observed in several other countries, small-scale gold mining in Compostela Valley (ComVal) province has expanded immensely, and now boasts a high number of more advanced i.e. more capitalized and mechanized operations that push the edge of what is usually considered artisanal and small-scale mining (ASM). A historical, fieldwork-based analysis is presented of the diverse factors underlying the current situation. It is argued that existing accounts of ASM-expansion, by focusing disproportionately on the role of poverty in pushing people into ASM, fail to satisfactorily account for the state of gold mining in ComVal. Whereas this poverty-driven narrative may well explain the constant supply of mining recruits, it risks obscuring how for certain groups, ASM harbors important opportunities for capital accumulation. More specifically, the increased engagement in gold mining on the part of a heterogeneous class of mining financiers enabled ASM to evolve from rudimentary into relatively mechanized operations with highly complex working practices and revenue sharing arrangements. The nascent gold mining elite has entrenched itself in a regulatory environment amenable to the further expansion of gold mining. These observations suggest that more critical attention should be paid to the 'capital interests' driving similar transformations of ASM elsewhere. © 2014 Elsevier Ltd.
De Bruyn B.,Ghent University
Journal of Combinatorial Theory. Series A | Year: 2011
Let δ be a thick dual polar space and F a convex subspace of diameter at least 2 of δ. Every hyperplane G of the subgeometry Fsp̃ of δ induced on F will give rise to a hyperplane H of δ, the so-called extension of G. We show that F and G are in some sense uniquely determined by H. We also consider the following problem: if e is a full projective embedding of δ and if eF is the full embedding of Fsp̃ induced by e, does the fact that G arises from the embedding eF imply that H arises from the embedding eδ We will study this problem in the cases that e is an absolutely universal embedding, a minimal full polarized embedding or a Grassmann embedding of a symplectic dual polar space. Our study will allow us to prove that if e is absolutely universal, then also eF is absolutely universal. © 2010 Elsevier Inc.
Vansteelandt S.,Ghent University |
Keiding N.,Copenhagen University
American Journal of Epidemiology | Year: 2011
In this issue of the Journal, Snowden et al. (Am J Epidemiol. 2011;173(7):731-738) give a didactic explanation of G-computation as an approach for estimating the causal effect of a point exposure. The authors of the present commentary reinforce the idea that their use of G-computation is equivalent to a particular form of model-based standardization, whereby reference is made to the observed study population, a technique that epidemiologists have been applying for several decades. They comment on the use of standardized versus conditional effect measures and on the relative predominance of the inverse probability-of-treatment weighting approach as opposed to G-computation. They further propose a compromise approach, doubly robust standardization, that combines the benefits of both of these causal inference techniques and is not more difficult to implement. © 2011 The Author.
Pauwels L.,VIB |
Goossens A.,Ghent University
Plant Cell | Year: 2011
Jasmonates are phytohormones that regulate many aspects of plant growth, development, and defense. Within the signaling cascades that are triggered by jasmonates, the JASMONATE-ZIM DOMAIN (JAZ) repressor proteins play a central role. The endogenous bioactive JA-Ile conjugate mediates the binding of JAZ proteins to the F-box protein CORONATINE INSENSITIVE1 (COI1), part of the Skp1/Cullin/F-box SCFCOI1 ubiquitin E3 ligase complex. Upon the subsequent destruction of the JAZ proteins by the 26S proteasome, multiple transcription factors are relieved from JAZ-mediated repression, allowing them to activate their respective downstream responses. However, many questions remain regarding the targets, specificity, function, and regulation of the different JAZ proteins. Here, we review recent studies on the model plant Arabidopsis thaliana that provided essential and novel insights. JAZ proteins have been demonstrated to interact with a broad array of transcription factors that each control specific downstream processes. Recruitment of the corepressor TOPLESS unveiled a mechanism for JAZ-mediated gene repression. Finally, the presence of JAZ proteins was also found to be regulated by alternative splicing and interactions with proteins from other hormonal signaling pathways. Overall, these contemporary findings underscore the value of protein-protein interaction studies to acquire fundamental insight into molecular signaling pathways. © 2011 American Society of Plant Biologists. All rights reserved.
Haegeman A.,Ghent University |
Jones J.T.,SCRI |
Danchin E.G.J.,French National Institute for Agricultural Research
Molecular Plant-Microbe Interactions | Year: 2011
The origin of plant parasitism within the phylum Nematoda is intriguing. The ability to parasitize plants has originated independently at least three times during nematode evolution and, as more molecular data has emerged, it has become clear that multiple instances of horizontal gene transfer (HGT) from bacteria and fungi have played a crucial role in the nematode's adaptation to this new lifestyle. The first reported HGT cases in plant-parasitic nematodes were genes encoding plant cell wall-degrading enzymes. Other putative examples of HGT were subsequently described, including genes that may be involved in the modulation of the plant's defense system, the establishment of a nematode feeding site, and the synthesis or processing of nutrients. Although, in many cases, it is difficult to pinpoint the donor organism, candidate donors are usually soil dwelling and are either plant-pathogenic or plant-associated microorganisms, hence occupying the same ecological niche as the nematodes. The exact mechanisms of transfer are unknown, although close contacts with donor microorganisms, such as symbiotic or trophic interactions, are a possibility. The widespread occurrence of horizontally transferred genes in evolutionarily independent plant-parasitic nematode lineages suggests that HGT may be a prerequisite for successful plant parasitism in nematodes. © 2011 The American Phytopathological Society.
Schockaert S.,Ghent University |
Prade H.,French National Center for Scientific Research
Artificial Intelligence | Year: 2011
Although many techniques for merging conflicting propositional knowledge bases have already been proposed, most existing work is based on the idea that inconsistency results from the presence of incorrect pieces of information, which should be identified and removed. In contrast, we take the view in this paper that conflicts are often caused by statements that are inaccurate rather than completely false, suggesting to restore consistency by interpreting certain statements in a flexible way, rather than ignoring them completely. In accordance with this view, we propose a novel approach to merging which exploits extra-logical background information about the semantic relatedness of atomic propositions. Several merging operators are presented, which are based on different formalizations of this background knowledge, ranging from purely qualitative approaches, related to possibilistic logic, to quantitative approaches with a probabilistic flavor. Both syntactic and semantic characterizations are provided for each merging operator, and the computational complexity is analyzed. © 2011 Elsevier B.V.
Van Damme S.,Ghent University |
Kindermans H.,Maastricht University
Clinical Journal of Pain | Year: 2015
OBJECTIVE:: Behavioral factors such as avoidance and persistence have received massive theoretical and empirical attention in the attempts to explain chronic pain and disability. The determinants of these pain behaviors remain, however, poorly understood. We propose a self-regulation perspective to increase our understanding of pain-related avoidance and persistence. METHODS:: A narrative review. RESULTS:: We identified several theoretical views that may help explaining avoidance and persistence behavior, and organized these views around 4 concepts central in self-regulation theories: (1) identity, (2) affective-motivational orientation, (3) goal cognitions, and (4) coping. The review shows that each of these self-regulation perspectives allows for a broadened view in which pain behaviors are not simply considered passive consequences of fear, but proactive strategies to regulate the self when challenged by pain. DISCUSSION:: Several implications and challenges arising from this review are discussed. In particular, a self-regulation perspective does not consider avoidance and persistence behavior to be intrinsically adaptive or maladaptive, but argues that their effects on disability and well-being rather depend on the goals underlying these behaviors. Such view would require a shift in how avoidance and persistence behavior are assessed and approached in clinical interventions. © 2014 Wolters Kluwer Health, Inc.
Barbez E.,University of Natural Resources and Life Sciences, Vienna |
Barbez E.,Ghent University |
Kleine-Vehn J.,University of Natural Resources and Life Sciences, Vienna
Current Opinion in Plant Biology | Year: 2013
The phytohormone auxin is an essential regulator for plant growth and development. Decades of intensive research revealed the mutual importance of auxin metabolism and intercellular cell-to-cell transport for the regulation of spatiotemporal auxin distribution. Just recently, intracellular putative auxin carriers, such as the PIN-FORMED (PIN)5/PIN8 and the PIN-LIKES (PILS)2/PILS5 were discovered at the endoplasmic reticulum (ER) and seem to limit nuclear auxin signaling via an auxin sequestration mechanism. Moreover, these auxin carriers at the ER might provide a link between auxin compartmentalization and auxin conjugation-based metabolism. Here we review the recent findings on auxin compartmentalization at the ER and discuss its potential contribution to cellular auxin homeostasis and its importance for plant development. © 2012 Elsevier Ltd.
Vanholder R.,Ghent University
Critical care (London, England) | Year: 2011
The question of whether renal replacement therapy should be applied in an intermittent or continuous mode to the patient with acute kidney injury has been the topic of several controlled studies and meta-analyses. Although continuous renal replacement therapy (CRRT) has a theoretical advantage due to offering the opportunity to remove excess fluid more gradually, none of the several outcome studies that have been undertaken in the meanwhile was able to demonstrate its superiority over intermittent renal replacement therapy (IRRT). In the present article, therefore, questions are raised regarding which are the specific advantages of each strategy, and which are the specific populations that might benefit from their application. Although several advantages have been attributed to CRRT - especially more hemodynamic stability allowing more adequate fluid removal, better recovery of renal function, and more efficient removal of small and large metabolites - none of these could be adequately proven in controlled trials. CRRT is claimed to be better tolerated in combined acute liver and kidney failure and in acute brain injury. IRRT is more practical, flexible and cost-effective, allows the clinician to discontinue or to minimize anticoagulation with bleeding risks, and removes small solutes such as potassium more efficiently in acute life-threatening conditions. Sustained low-efficiency daily dialysis is a hybrid therapy combining most of the advantages of both options. © 2011 BioMed Central Ltd
Dhollander A.A.,Ghent University
The journal of knee surgery | Year: 2012
Long after the first reports on human autologous chondrocyte implantation (ACI) by Brittberg in 1994, the development of a so-called optimal technology for osteochondral tissue regeneration is still one of the most challenging issues in knee surgery. Although the short- and intermediate-term results of ACI appear to be favorable, resources are being directed toward scaffold research to improve the technology. Scaffolds used for osteochondral repair may be either cell or noncell-based before its implantation in the knee. The characteristics that make scaffolds optimal for clinical use are that they be biocompatible, biodegradable, permeable, reproducible, mechanically stable, noncytotoxic, and capable of serving as a temporary support for the cells while allowing for eventual replacement by matrix components synthesized by the implanted cells. There is a growing interest in noncell and last-minute cell seeding technologies since they allow for a one-step surgery eliminating the morbidity and necessity of a previous chondral biopsy. Although clinical and histological results from many, already clinically available scaffolds seem to be promising, improvements throughout these technologies and the developments of new ones are still necessary to obtain a more efficient biological response as well as to improve the implant's stability. Moreover, as the understanding of interactions between articular cartilage and subchondral bone continues to evolve, increased attention should be directed at treatment options for the entire osteochondral unit, rather than focusing on the articular surface only.
Ryckebosch E.,Sudan University of Science and Technology |
Drouillon M.,Ghent University |
Vervaeren H.,West-Flanders College
Biomass and Bioenergy | Year: 2011
Biogas from anaerobic digestion and landfills consists primarily of CH4 and CO2. Trace components that are often present in biogas are water vapor, hydrogen sulfide, siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide and nitrogen. In order to transfer biogas into biomethane, two major steps are performed: (1) a cleaning process to remove the trace components and (2) an upgrading process to adjust the calorific value. Upgrading is generally performed in order to meet the standards for use as vehicle fuel or for injection in the natural gas grid. Different methods for biogas cleaning and upgrading are used. They differ in functioning, the necessary quality conditions of the incoming gas, the efficiency and their operational bottlenecks. Condensation methods (demisters, cyclone separators or moisture traps) and drying methods (adsorption or absorption) are used to remove water in combination with foam and dust. A number of techniques have been developed to remove H2S from biogas. Air dosing to the biogas and addition of iron chloride into the digester tank are two procedures that remove H2S during digestion. Techniques such as adsorption on iron oxide pellets and absorption in liquids remove H2S after digestion. Subsequently, trace components like siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide and nitrogen can require extra removal steps, if not sufficiently removed by other treatment steps. Finally, CH4 must be separated from CO2 using pressure swing adsorption, membrane separation, physical or chemical CO2-absorption. © 2011 Elsevier Ltd.
Verbeke W.,Ghent University
Agro Food Industry Hi-Tech | Year: 2011
This contribution provides a summary of insights about consumer attitudes towards agro-food technologies. The main factors that shape consumer acceptance or rejection are highlighted from recent review papers and linked with risk perception. Evidence from beef processing technologies confirms that the presence of a bioactive component or safetyenhancing benefit associated with the technology fuels consumer concern. Communication challenges are discussed, in particular the challenge to find the right balance between informing markets in a transparent way without overloading them with too much information detail.
Demoucron M.,Ghent University
Acta Acustica united with Acustica | Year: 2015
In the playing of bowed-string instruments, bow changes are subtle technical gestures that are used to reverse the bowing direction, from up-bow to down-bow or the other way around. In this study, simulations are performed with a simple control model of the change in order to examine the characteristic features involved in the reversal of direction. The operating parameters of this model are the bow deceleration before zero bow velocity and the subsequent bow acceleration, while the other bowing parameters are kept constant. The simulations show optimal areas in the space of control parameters, where the probability to produce a subsequent Helmholtz motion is higher. Further developments based on Guettler's analysis of simple attacks show that these optimal areas are closely linked to the specific shape of the oscillation remaining from the previous note ending. Finally, we discuss some gestural strategies that can be used by players to reduce possible interferences between the remaining oscillations and the subsequent attack. © S. Hirzel Verlag · EAA.
de Veylder L.,Vlaams Institute for Biotechnology |
de Veylder L.,Ghent University |
Larkin J.C.,University of Strasbourg |
Larkin J.C.,Louisiana State University |
Schnittger A.,University of Strasbourg
Trends in Plant Science | Year: 2011
Endoreplication, also called endoreduplication, is a cell cycle variant of multicellular eukaryotes in which mitosis is skipped and cells repeatedly replicate their DNA, resulting in cellular polyploidy. In recent years, research results have shed light on the molecular mechanism of endoreplication control, but the function of this cell-cycle variant has remained elusive. However, new evidence is at last providing insight into the biological relevance of cellular polyploidy, demonstrating that endoreplication is essential for developmental processes, such as cell fate maintenance, and is a prominent response to physiological conditions, such as pathogen attack or DNA damage. Thus, endoreplication is being revealed as an important module in plant growth that contributes to the robustness of plant life. © 2011 Elsevier Ltd.
Hoogenboom R.,Ghent University
European Journal of Lipid Science and Technology | Year: 2011
Poly(2-oxazoline)s are an interesting class of synthetic poly(amide)s that can be prepared by living cationic ring-opening polymerization. The properties of poly(2-oxazoline)s can be tuned by variation of the 2-substituent of the 2-oxazoline monomer. In this contribution the utilization of fatty acids as side chains for poly(2-oxazoline)s is highlighted. The incorporation of such long aliphatic side-chains results in hydrophobic crystalline poly(2-oxazoline)s that are often applied for the preparation of amphiphilic structures as well as for low surface energy and low adhesive coatings. The most popular fatty-acid based poly(2-oxazoline)s are the saturated poly(2-nonyl-2-oxazoline) and poly(2-undecyl-2-oxazoline) as well as the unsaturated poly(2-decenyl-2-oxazoline) and poly(2-"soy alkyl"-2-oxazoline). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Van Montagu M.,Ghent University
Annual Review of Plant Biology | Year: 2011
When we discovered that crown gall induction on plants by Agrobacterium tumefaciens is a natural event of genetic engineering, we were convinced that this was the dawn of a new era for plant science. Now, more than 30 years later, I remain overawed by how far and how rapidly we progressed with our knowledge of the molecular basis of plant growth, development, stress resistance, flowering, and ecological adaptation, thanks to the gene engineering technology. I am impressed, but also frustrated by the difficulties of applying this knowledge to improve crops and globally develop a sustainable and improved high-yielding agriculture. Now that gene engineering has become so efficient, I had hoped that thousands of teams, all over the world, would work on improving our major food crops, help domesticate new ones, and succeed in doubling or tripling biomass yields in industrial crops. We live in a world where more than a billion people are hungry or starving, while the last areas of tropical forest and wild nature are disappearing. We urgently need a better supply of raw material for our chemical industry because petroleum-based products pollute the environment and are limited in supply. Why could this new technology not bring the solutions to these challenges? Why has this not happened yet; what did we do wrong?. Copyright © 2011 by Annual Reviews. All rights reserved.
Beeckman D.,Ghent University
Journal of Tissue Viability | Year: 2016
Background: Incontinence-Associated Dermatitis (IAD) is one of the clinical manifestations of Moisture- Associated Skin Damage (MASD). IAD is a common problem in aged patients with fecal and/or urinary incontinence. Aim: Update about IAD terminology, etiology, epidemiology, observation, prevention, and treatment. Methods: Integrative review. Results: The lack of an ICD-10 code and an internationally validated and standardized method for IAD data collection contribute to a variation in epidemiological data. Frequent episodes of incontinence (especially fecal), occlusive containment products, poor skin condition, reduced mobility, diminished cognitive awareness, inability to perform personal hygiene, pain, pyrexia, certain medications (antibiotics, immunosuppressants), poor nutritional status, and critical illness are associated with IAD. Correctly diagnosing IAD and distinguish it from pressure ulcers is difficult. Even though the clinical presentation of partial thickness pressure ulcers and IAD is similar, the underlying etiologic factors differ. However, incontinence and IAD were found to be risk factors for pressure ulcer development. IAD management should essentially focus on skin cleansing to remove dirt, debris and microorganisms; skin moisturization to repair or augment the skin's barrier; and the application of a skin barrier product to prevent skin breakdown by providing an impermeable or semi-permeable barrier on the skin. The body of evidence is still limited, but growing since the last decade. Conclusion: Incontinence causes disruptions of the skin barrier function and leads to superficial skin damage. Macerated skin and superficial skin changes due to incontinence are associated with pressure ulcer development. Skin maceration, chemical irritation, and physical irritation should be targeted to effectively prevent and treat IAD. © 2016 Tissue Viability Society.
Verbeke W.,Ghent University
Food Quality and Preference | Year: 2015
This study investigates the readiness of consumers in a Western society, where traditional meat consumption prevails, to adopt insects as a substitute for meat. Using cross-sectional data (n= 368) and binary logistic regression modeling, the study identifies gender, age, familiarity, food neophobia, convenience and environmental food choice motives, as well as meat-related attitudes and future meat consumption intentions as significant predictors. The predicted likelihood of adopting insects as a substitute for meat is 12.8% [95% CI: 6.1-19.4%] for males and 6.3% [95% CI: 2.8-9.9%] for females, other predictor variables held constant at their mean value. People who claim to be familiar with the idea of eating insects have a 2.6 times higher likelihood, and consumers who intend to reduce fresh meat intake are up to 4.5 times more likely to adopt insects. Food neophobia makes the largest contribution to consumers' readiness to adopt insects: a one-unit increase in the food neophobia score is associated with a 84% decrease in the predicted odds of being ready to adopt insects. A stronger convenience orientation in food choice and a higher interest in the environmental impact of food choice increase the likelihood of adopting insects by 75% and 71% per unit increase in these predictors' scores, respectively. By contrast, a one-unit stronger belief that meat is nutritious and healthy, and a one-unit higher importance attached to taste for meat lower the predicted odds by 64% and 61%, respectively. This study reveals that the most likely early adopters of insects as a novel and more sustainable protein source in Western societies are younger males with a weak attachment to meat, who are more open to trying novel foods and interested in the environmental impact of their food choice. © 2014 Elsevier Ltd.
Miralles D.G.,University of Bristol |
Miralles D.G.,Ghent University |
Teuling A.J.,Wageningen University |
Van Heerwaarden C.C.,Max Planck Institute for Meteorology |
De Arellano J.V.-G.,Wageningen University
Nature Geoscience | Year: 2014
The recent European mega-heatwaves of 2003 and 2010 broke temperature records across Europe. Although events of this magnitude were unprecedented from a historical perspective, they are expected to become common by the end of the century. However, our understanding of extreme heatwave events is limited and their representation in climate models remains imperfect. Here we investigate the physical processes underlying recent mega-heatwaves using satellite and balloon measurements of land and atmospheric conditions from the summers of 2003 in France and 2010 in Russia, in combination with a soil-water-atmosphere model. We find that, in both events, persistent atmospheric pressure patterns induced land-atmosphere feedbacks that led to extreme temperatures. During daytime, heat was supplied by large-scale horizontal advection, warming of an increasingly desiccated land surface and enhanced entrainment of warm air into the atmospheric boundary layer. Overnight, the heat generated during the day was preserved in an anomalous kilometres-deep atmospheric layer located several hundred metres above the surface, available to re-enter the atmospheric boundary layer during the next diurnal cycle. This resulted in a progressive accumulation of heat over several days, which enhanced soil desiccation and led to further escalation in air temperatures. Our findings suggest that the extreme temperatures in mega-heatwaves can be explained by the combined multi-day memory of the land surface and the atmospheric boundary layer. © 2014 Macmillan Publishers Limited.
Thorleuchter D.,Fraunhofer Institute for Technological Trend Analysis |
Van Den Poel D.,Ghent University
Expert Systems with Applications | Year: 2012
We analyze the impact of textual information from e-commerce companies' websites on their commercial success. The textual information is extracted from web content of e-commerce companies divided into the Top 100 worldwide most successful companies and into the Top 101 to 500 worldwide most successful companies. It is shown that latent semantic concepts extracted from the analysis of textual information can be adopted as success factors for a Top 100 e-commerce company classification. This contributes to the existing literature concerning e-commerce success factors. As evaluation, a regression model based on these concepts is built that is successful in predicting the commercial success of the Top 100 companies. These findings are valuable for e-commerce websites creation. © 2012 Elsevier Ltd. All rights reserved.
Ghyselinck J.,Ghent University
PloS one | Year: 2013
Different regions of the bacterial 16S rRNA gene evolve at different evolutionary rates. The scientific outcome of short read sequencing studies therefore alters with the gene region sequenced. We wanted to gain insight in the impact of primer choice on the outcome of short read sequencing efforts. All the unknowns associated with sequencing data, i.e. primer coverage rate, phylogeny, OTU-richness and taxonomic assignment, were therefore implemented in one study for ten well established universal primers (338f/r, 518f/r, 799f/r, 926f/r and 1062f/r) targeting dispersed regions of the bacterial 16S rRNA gene. All analyses were performed on nearly full length and in silico generated short read sequence libraries containing 1175 sequences that were carefully chosen as to present a representative substitute of the SILVA SSU database. The 518f and 799r primers, targeting the V4 region of the 16S rRNA gene, were found to be particularly suited for short read sequencing studies, while the primer 1062r, targeting V6, seemed to be least reliable. Our results will assist scientists in considering whether the best option for their study is to select the most informative primer, or the primer that excludes interferences by host-organelle DNA. The methodology followed can be extrapolated to other primers, allowing their evaluation prior to the experiment.
Thorleuchter D.,Fraunhofer Institute for Technological Trend Analysis |
Van Den Poel D.,Ghent University
Expert Systems with Applications | Year: 2012
Multilevel security (MLS) is specifically created to protect information from unauthorized access. In MLS, documents are assigned to a security label by a trusted subject e.g. an authorized user and based on this assignment; the access to documents is allowed or denied. Using a large number of security labels lead to a complex administration in MLS based operating systems. This is because the manual assignment of documents to a large number of security labels by an authorized user is time-consuming and error-prone. Thus in practice, most MLS based operating systems use a small number of security labels. However, information that is normally processed in an organization consists of different sensitivities and belongs to different compartments. To depict this information in MLS, a large number of security labels is necessary. The aim of this paper is to show that the use of latent semantic indexing is successful in assigning textual information to security labels. This supports the authorized user by his manual assignment. It reduces complexity by the administration of a MLS based operating system and it enables the use of a large number of security labels. In future, the findings probably will lead to an increased usage of these MLS based operating systems in organizations. © 2012 Elsevier Ltd. All rights reserved.
Ceelen W.P.,Ghent University
European Surgical Research | Year: 2014
Surgery is a discipline which profoundly affects human integrity. Therefore, there is an ethical and scientific imperative that surgical practice depends on the best possible trial-based evidence. Traditionally, the quality and quantity of clinical research have been lagging behind other disciplines in clinical medicine. However, recent collaborative initiatives, such as the IDEAL framework which tests surgical innovation, international registries, and quality assurance platforms, the development of modified randomized controlled trials and alternative trial designs as well as the impending reforms of the regulatory framework surrounding non pharmaceutical interventions and devices offer significant and timely opportunities to enhance the relevance of clinical research in surgery. Here, we provide an overview of the current state of clinical research in surgery, identify possible obstacles, and discuss realistic and emerging solutions that have the potential to change the way surgical research is organized, funded, and translated to the patient's benefit. © 2014 S. Karger AG, Basel.
Boute R.,Ghent University
IEEE Signal Processing Magazine | Year: 2012
Bandpass sampling (BPS) means sampling a bandlimited signal at rates below the baseband Nyquist rate (defined as twice the highest frequency in the signal spectrum) and still allowing reconstruction. © 2012 IEEE.
Van de Graaf T.,Ghent University
Global Environmental Politics | Year: 2013
In 2009, a group of member countries of the International Energy Agency (IEA) spearheaded the creation of a new international organization, the International Renewable Energy Agency (IRENA), despite the fact that the IEA had been working on renewables for decades. Why would states create an overlapping organization, thus advancing the overall degree of fragmentation? Drawing on the work of Mansfield and Moravcsik, this article provides an explanation based on domestic preferences and institutional capture. Viewed thus, IRENA was part of an institutional hedging strategy instigated by domestic actors in Germany and allied states to counter the IEA's alleged normative bias toward the fossil and nuclear energy industries with a wider set of alternative energy options. The article suggests that, depending on the domestic preferences of a set of states capable to innovate, the transaction costs associated with institutional reform may surmount those of institutional creation. © 2013 by the Massachusetts Institute of Technology.
van Helden M.J.,Inflammation Research Center |
Lambrecht B.N.,Inflammation Research Center |
Lambrecht B.N.,Ghent University |
Lambrecht B.N.,Erasmus University Rotterdam
Current Opinion in Immunology | Year: 2013
The lungs are constantly exposed to antigens, most of which are non-pathogenic and do not require the induction of an immune response. Dendritic cells (DCs) are situated at the basolateral site of the lungs and continuously scan the environment to detect the presence of pathogens and subsequently initiate an immune response. They are a heterogeneous population of antigen-presenting cells that exert specific functions. Compelling evidence is now provided that DCs are both sufficient and necessary to induce allergic responses against several inhaled harmless allergens. How various DC subsets exactly contribute to the induction of allergic asthma is currently a subject of intense investigation. We here review the current progress in this field. © 2013 Elsevier Ltd.
Van Strien M.,Ghent University
Studies in History and Philosophy of Science Part B - Studies in History and Philosophy of Modern Physics | Year: 2013
The reversibility problem (better known as the reversibility objection) is usually taken to be an internal problem in the kinetic theory of gases, namely the problem of how to account for the second law of thermodynamics within this theory. Historically, it is seen as an objection that was raised against Boltzmann's kinetic theory of gases, which led Boltzmann to a statistical approach to the kinetic theory, culminating in the development of statistical mechanics. In this paper, I show that in the late nineteenth century, the reversibility problem had a much broader significance-it was widely discussed and certainly not only as an objection to Boltzmann's kinetic theory of gases. In this period, there was a conflict between mechanism and irreversibility in physics which was tied up with central issues in philosophy of science such as materialism, empiricism and the need for mechanistic foundations of physical theories, as well as with concerns about the heat death of the universe. I discuss how this conflict was handled by the major physicists of the period, such as Maxwell, Kelvin, Duhem, Poincaré, Mach and Planck, as well as by a number of lesser-known authors. © 2013 Elsevier Ltd.
Rombout A.,Ghent University
British Journal of Cancer | Year: 2016
Background:The B-cell receptor (BCR) has a key role in the cross-talk between chronic lymphocytic leukaemia (CLL) cells and the tissue microenvironment, which favours disease progression by promoting proliferation and drug resistance. In vitro studies on downstream signalling and functional effects of CLL BCR ligation often report contradictory results, in part owing to the lack of a standardised stimulation protocol. Our aim was to define a biologically relevant and robust in vitro stimulation method with regard to cellular phenotypic and transcriptional responses.Methods:We evaluated mRNA (FOS, MYC, LPL) and protein (CD54, CD19, CD62L, CD184) expression of genes modulated by BCR triggering in immunoglobulin heavy-chain variable region genes (IGHV)-mutated and -unmutated CLL cells, after stimulation using soluble or immobilised anti-IgM antibodies from different suppliers.Results:The effect of BCR stimulation on gene and protein expression was comparable in all CLL patients, irrespective of IGHV mutation status. However, immobilised anti-IgM stimulation elicited clear and robust changes in gene and protein expression, whereas the response to soluble anti-IgM was far less obvious.Conclusions:These data indicate that the method of BCR stimulation is of major importance regarding responsiveness of CLL cells in the context of the tumour microenvironment, whereas genetic differences in the BCR pathway are less critical.British Journal of Cancer advance online publication, 25 February 2016; doi:10.1038/bjc.2016.35 www.bjcancer.com. © 2016 Cancer Research UK
Fattibene P.,Istituto Superiore di Sanita |
Callens F.,Ghent University
Applied Radiation and Isotopes | Year: 2010
When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry using tooth enamel is based on the (presumed) correlation between the intensity or amplitude of some of the radiation-induced signals with the dose absorbed in the enamel. In the present paper a critical review is given of this widely applied dosimetric method. The first part of the paper is fairly fundamental and deals with the main properties of tooth enamel and some of its model systems (e.g., synthetic apatites). Considerable attention is also paid to the numerous radiation-induced and native EPR signals and the radicals responsible for them. The relevant methods for EPR detection, identification and spectrum analyzing are reviewed from a general point of view. Finally, the needs for solid-state modelling and studies of the linearity of the dose response are investigated. The second part is devoted to the practical implementation of EPR dosimetry using enamel. It concerns specific problems of preparation of samples, their irradiation and spectrum acquisition. It also describes how the dosimetric signal intensity and dose can be retrieved from the EPR spectra. Special attention is paid to the energy dependence of the EPR response and to sources of uncertainties. Results of and problems encountered in international intercomparisons and epidemiological studies are also dealt with. In the final section the future of EPR dosimetry with tooth enamel is analyzed. © 2010 Elsevier Ltd.
Adriaens A.,Ghent University |
Dowsett M.,University of Warwick
Accounts of Chemical Research | Year: 2010
Corrosion is a major source of degradation in heritage metal objects, and any remedial measures are subject to a strong (Western) ethic that favors conservation as opposed to restoration. Accordingly, major scientific challenges exist for developing appropriate treatment methods to stabilize and protect artifacts after they are recovered from an archaeological site, both before and during their display or storage in a museum. Because inappropriate treatments can cause irreversible damage to irreplaceable objects, it is crucial that the chemical processes involved are fully understood and characterized before any preservation work is undertaken. In this regard, large infrastructural facilities such as synchrotrons, neutron sources, and particle accelerators provide a wealth of analytical possibilities, unavailable in smaller scale laboratories. In general, the intensity of the radiation available allows measurements on a short time scale or with high spatial resolution (or both), so heterogeneous changes induced by a chemical process can be recorded while they occur. The penetrative nature of the radiation (e.g., X-rays, protons, or neutrons) also allows a sample to be studied in air. If necessary, complete artifacts (such as paintings or statuettes) can be examined. In situ analysis in a controlled environment, such as a liquid or corrosive atmosphere, also becomes an exciting possibility. Finally, there are many complementary techniques (local atomic structure or crystal structure determination, macroscopic 3-D imaging (tomographies), imaging chemical analysis, and so on) so the many distinct details of a problem can be thoroughly explored. In this Account, we discuss the application of this general philosophy to studies of corrosion and its prevention in cultural heritage metals, focusing on our recent work on copper alloys. More specifically, we use synchrotron-based techniques to evaluate the use of corrosion potential measurements as a possible monitoring method for copper-based objects recovered from marine environments. The extraction of chlorides from such artifacts is a process that must take place before the artifacts are put on display or stored, because air exposure of untreated metal will result in severe damage or loss in as little as a few weeks. Chloride is removed by soaking the artifact for up to two years in tap water or dilute sodium sesquicarbonate, with regular solution changes. Our research supports the effectiveness of this treatment for thin nantokite (copper(I) chloride) layers, but it raises questions for copper hydroxychlorides (atacamite and paratacamite), especially when these minerals are trapped in fissures. Electrochemical parameters such as the corrosion potential are shown to be insensitive to the physical presence of large hydroxychloride coverages if they overlie a cuprite (Cu2O) layer. X-ray absorption spectroscopy proves to be a good monitor for the chloride in solution over the working electrode, whereas X-ray diffraction offers the potential for real-time measurement of the surface chloride composition. In principle, the two techniques together offer the possibility of monitoring surface and fluid levels simultaneously. © 2010 American Chemical Society.
Devisch I.,Ghent University
Health Care Analysis | Year: 2012
In this article, we focus at a key concept of today's healthcare, namely responsibility. Personal responsibility is so important today because it is obvious that the way society is organized, many people are facing a lot of difficulties to live their lives in a responsible way. We explicitly obtain an analysis of responsibility from a view which avoids the binary thinking which is so remarkably present in today's health care discourse. The aim of this pilot study is therefore to open up the horizon of the use of responsibility in today's healthcare. We develop the notion of 'co-responsibility' to understand how individuals, despite the fact they are responsible for their own agency, are always also affected by an ought which contaminates their efforts to fulfill their duties and obligations. We discuss co-responsibility not as conclusion or a magic formula to all problems, but as a new starting point of which we have to explore the opportunities for current and future health care dilemmas. © Springer Science+Business Media, LLC 2011.
Lambrecht B.N.,Laboratory of Immunoregulation and Mucosal Immunology |
Lambrecht B.N.,Ghent University |
Lambrecht B.N.,Erasmus Medical Center |
Hammad H.,Laboratory of Immunoregulation and Mucosal Immunology
Annual Review of Immunology | Year: 2012
Lung dendritic cells (DCs) bridge innate and adaptive immunity, and depending on context, they also induce a Th1, Th2, or Th17 response to optimally clear infectious threats. Conversely, lung DCs can also mount maladaptive Th2 immune responses to harmless allergens and, in this way, contribute to immunopathology. It is now clear that the various aspects of DC biology can be understood only if we take into account the functional specializations of different DC subsets that are present in the lung in homeostasis or are attracted to the lung as part of the inflammatory response to inhaled noxious stimuli. Lung DCs are heavily influenced by the nearby epithelial cells, and a model is emerging whereby direct communication between DCs and epithelial cells determines the outcome of the pulmonary immune response. Here, we have approached DC biology from the perspective of viral infection and allergy to illustrate these emerging concepts. © 2012 by Annual Reviews. All rights reserved.
Eeckhout L.,Ghent University
Synthesis Lectures on Computer Architecture | Year: 2010
Performance evaluation is at the foundation of computer architecture research and development. Contemporary microprocessors are so complex that architects cannot design systems based on intuition and simple models only. Adequate performance evaluation methods are absolutely crucial to steer the research and development process in the right direction. However, rigorous performance evaluation is non-trivial as there are multiple aspects to performance evaluation, such as picking workloads, selecting an appropriate modeling or simulation approach, running the model and interpreting the results using meaningful metrics. Each of these aspects is equally important and a performance evaluation method that lacks rigor in any of these crucial aspects may lead to inaccurate performance data and may drive research and development in a wrong direction. The goal of this book is to present an overview of the current state-of-the-art in computer architecture performance evaluation, with a special emphasis on methods for exploring processor architectures. The book focuses on fundamental concepts and ideas for obtaining accurate performance data. The book covers various topics in performance evaluation, ranging from performance metrics, to workload selection, to various modeling approaches including mechanistic and empirical modeling. And because simulation is by far the most prevalent modeling technique, more than half the book's content is devoted to simulation. The book provides an overview of the simulation techniques in the computer designer's toolbox, followed by various simulation acceleration techniques including sampled simulation, statistical simulation, parallel simulation and hardware-accelerated simulation. Copyright © 2010 by Morgan & Claypool.
Garcia-Ramos J.E.,University of Huelva |
Heyde K.,Ghent University
Physical Review C - Nuclear Physics | Year: 2014
Background: The Po, Pb, Hg, and Pt region is known for the presence of coexisting structures that correspond to different particle-hole configurations in the shell model language or equivalently to nuclear shapes with different deformation. Purpose: We intend to study the configuration mixing phenomenon in the Hg isotopes and to understand how different observables are influenced by it. Method: We study in detail a long chain of mercury isotopes, 172 - 200Hg, using the interacting boson model with configuration mixing. The parameters of the Hamiltonians are fixed through a least-squares fit to the known energies and absolute B(E2) transition rates of states up to 3 MeV. Results: We obtained the IBM-CM Hamiltonians and we calculate excitation energies, B(E2)'s, quadrupole shape invariants, wave functions, isotopic shifts, and mean-field energy surfaces. Conclusions: We obtain a fairly good agreement with the experimental data for all the studied observables and we conclude that the Hamiltonian and the states we obtain constitute a good approximation to the Hg isotopes. © 2014 American Physical Society.
Broos S.,Ghent University
Nucleic acids research | Year: 2013
The most important mechanism in the regulation of transcription is the binding of a transcription factor (TF) to a DNA sequence called the TF binding site (TFBS). Most binding sites are short and degenerate, which makes predictions based on their primary sequence alone somewhat unreliable. We present a new web tool that implements a flexible and extensible algorithm for predicting TFBS. The algorithm makes use of both direct (the sequence) and several indirect readout features of protein-DNA complexes (biophysical properties such as bendability or the solvent-excluded surface of the DNA). This algorithm significantly outperforms state-of-the-art approaches for in silico identification of TFBS. Users can submit FASTA sequences for analysis in the PhysBinder integrative algorithm and choose from >60 different TF-binding models. The results of this analysis can be used to plan and steer wet-lab experiments. The PhysBinder web tool is freely available at http://bioit.dmbr.ugent.be/physbinder/index.php.
Dudal D.,Ghent University |
Guimaraes M.S.,State University of Rio de Janeiro |
Sorella S.P.,State University of Rio de Janeiro
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014
A Padé approximation approach, rooted in an infrared moment technique, is employed to provide mass estimates for various glueball states in pure gauge theories. The main input in this analysis are theoretically well-motivated fits to lattice gluon propagator data, which are by now available for both SU(2) and SU(3) in 3 and 4 space-time dimensions. We construct appropriate gauge invariant and Lorentz covariant operators in the (pseudo)scalar and (pseudo)tensor sector. Our estimates compare reasonably well with a variety of lattice sources directly aimed at extracting glueball masses. © 2014 The Authors.
Bouyssou D.,University of Paris Dauphine |
Marchant T.,Ghent University
Journal of the American Society for Information Science and Technology | Year: 2011
The standard data that we use when computing bibliometric rankings of scientists are their publication/ citation records, i.e., so many papers with 0 citation, so many with 1 citation, so many with 2 citations, etc. The standard data for bibliometric rankings of departments have the same structure. It is therefore tempting (and many authors gave in to temptation) to use the same method for computing rankings of scientists and rankings of departments. Depending on the method, this can yield quite surprising and unpleasant results. Indeed, with some methods, it may happen that the "best" department contains the "worst" scientists, and only them. This problem will not occur if the rankings satisfy a property called consistency, recently introduced in the literature. In this article, we explore the consequences of consistency and we characterize two families of consistent rankings. © 2011 ASIS&T.
Coenye T.,Ghent University
Future Microbiology | Year: 2010
Burkholderia cepacia complex bacteria are opportunistic pathogens that cause respiratory tract infections in susceptible patients, mainly people with cystic fibrosis. There is convincing evidence that B. cepacia complex bacteria can form biofilms, not only on abiotic surfaces (e.g., glass and plastics), but also on biotic surfaces such as epithelial cells, leading to the suggestion that biofilm formation plays a key role in persistent infection of cystic fibrosis lungs. This article presents an overview of the molecular mechanisms involved in B. cepacia complex biofilm formation, the increased resistance of sessile B. cepacia complex cells and the role of quorum sensing in B. cepacia complex biofilm formation. © 2010 Future Medicine Ltd.
Stillaert F.B.,Ghent University
Plastic and Reconstructive Surgery | Year: 2010
Background: Despite a revived interest in fat grafting procedures, clinicians still fail to demonstrate clearly the in vivo behavior of fat grafts as a dynamic tissue substitute. However, the basic principles in cellular biology teach us that cells can survive and develop, provided that a structural matrix exists that directs their behavior. The purpose of this in vitro study was to analyze that behavior of crude fat grafts, cultured on a three-dimensional laminin-rich matrix. Methods: Nonprocessed, human fat biopsy specimens (approximately 1 mm) were inoculated on Matrigel-coated wells to which culture medium was added. The control group consisted of fat biopsy specimens embedded in medium alone. The cellular proliferation pattern was followed over 6 weeks. Additional cultures of primary generated cellular spheroids were performed and eventually subjected to adipogenic differentiation media. Results: A progressive outgrowth of fibroblast-like cells from the core fat biopsy specimen was observed in both groups. Within the Matrigel group, an interconnecting three-dimensional network of spindle-shaped cells was established. This new cell colony reproduced spheroids that functioned again as solitary sources of cellular proliferation. Addition of differentiation media resulted in lipid droplet deposition in the majority of generated cells, indicating the initial steps of adipogenic differentiation. Conclusions: The authors noticed that crude, nonprocessed fat biopsy specimens do have considerable potential for future tissue engineering-based applications, provided that the basic principles of developmental, cellular biology are respected. Spontaneous in vitro expansion of the stromal cells present in fat grafts within autologous and injectable matrices could create "off-the-shelf" therapies for reconstructive procedures. Copyright © 2010 by the American Society of Plastic Surgeons.
De Block M.,Bayer BioScience N.V. |
Van Lijsebettens M.,Vlaams Institute for Biotechnology |
Van Lijsebettens M.,Ghent University
Current Opinion in Plant Biology | Year: 2011
The importance of energy metabolism in plant performance and plant productivity is conceptually well recognized. In the eighties, several independent studies in Lolium perenne (ryegrass), Zea mays (maize), and Festuca arundinacea (tall fescue) correlated low respiration rates with high yields. Similar reports in the nineties largely confirmed this correlation in Solanum lycopersicum (tomato) and Cucumis sativus (cucumber). However, selection for reduced respiration does not always result in high-yielding cultivars. Indeed, the ratio between energy content and respiration, defined here as energy efficiency, rather than respiration on its own, has a major impact on the yield potential of a crop. Besides energy efficiency, energy homeostasis, representing the balance between energy production and consumption in a changing environment, also contributes to an enhanced plant performance and this happens mainly through an increased stress tolerance. Although a few single gene approaches look promising, probably whole interacting networks have to be modulated, as is done by classical breeding, to improve the energy status of plants. Recent developments show that both energy efficiency and energy homeostasis have an epigenetic component that can be directed and stabilized by artificial selection (i.e. selective breeding). This novel approach offers new opportunities to improve yield potential and stress tolerance in a wide variety of crops. © 2011 Elsevier Ltd.
Sauer M.,CSIC - National Center for Biotechnology |
Kleine-Vehn J.,University of Natural Resources and Life Sciences, Vienna |
Kleine-Vehn J.,Ghent University
Plant Cell | Year: 2011
AUXIN BINDING PROTEIN1 (ABP1) is one of the first characterized proteins that bind auxin and has been implied as a receptor for a number of auxin responses. Early studies characterized its auxin binding properties and focused on rapid electrophysiological and cell expansion responses, while subsequent work indicated a role in cell cycle and cell division control. Very recently, ABP1 has been ascribed a role in modulating endocytic events at the plasma membrane and RHO OF PLANTS-mediated cytoskeletal rearrangements during asymmetric cell expansion. The exact molecular function of ABP1 is still unresolved, but its main activity apparently lies in influencing events at the plasma membrane. This review aims to connect the novel findings with the more classical literature on ABP1 and to point out the many open questions that still separate us from a comprehensive model of ABP1 action, almost 40 years after the first reports of its existence. © 2011 American Society of Plant Biologists. All rights reserved.
Van Dessel P.,Ghent University |
Vogt J.,University of Chicago
Frontiers in Human Neuroscience | Year: 2012
Prior evidence has shown that a person's affective context influences attention to emotional stimuli. The present study investigated whether a crossmodal affective context that is nduced by remembering an emotional sound modulates attention to visual emotional stimuli. One group of participants had to remember a positive, negative, or neutral sound during each trial of a dot probe paradigm. A second group of participants also had to encode the valence of the sound. The results revealed that attention was preferentially deployed to stimuli that were emotionally congruent to the affective context. However, this effect was only evident when participants had to encode the valence of the affective context. These findings suggest that a crossmodal affective context modulates the deployment of attention to emotional stimuli provided that the affective connotation of the context is task-relevant. © 2012 Van dessel and Vogt.
Thorleuchter D.,Fraunhofer Institute for Technological Trend Analysis |
Van Den Poel D.,Ghent University
Expert Systems with Applications | Year: 2014
Cross impact analysis (CIA) consists of a set of related methodologies that predict the occurrence probability of a specific event and that also predict the conditional probability of a first event given a second event. The conditional probability can be interpreted as the impact of the second event on the first. Most of the CIA methodologies are qualitative that means the occurrence and conditional probabilities are calculated based on estimations of human experts. In recent years, an increased number of quantitative methodologies can be seen that use a large number of data from databases and the internet. Nearly 80% of all data available in the internet are textual information and thus, knowledge structure based approaches on textual information for calculating the conditional probabilities are proposed in literature. In contrast to related methodologies, this work proposes a new quantitative CIA methodology to predict the conditional probability based on the semantic structure of given textual information. Latent semantic indexing is used to identify the hidden semantic patterns standing behind an event and to calculate the impact of the patterns on other semantic textual patterns representing a different event. This enables to calculate the conditional probabilities semantically. A case study shows that this semantic approach can be used to predict the conditional probability of a technology on a different technology. © 2012 Elsevier B.V. All rights reserved.
Lameire N.,Ghent University
Clinical Kidney Journal | Year: 2014
Cancer patients may develop a variety of kidney lesions that impair not only their immediate survival but also limit the adequate treatment of the underlying malignant process. This review summarizes the nephrotoxic potential of some of the most recently developed anti-cancer drugs, focusing on those interfering with the vascular endothelial growth factor and epidermal growth factor receptor pathways and mammalian target of rapamycin inhibitors. Thrombotic microangiopathy (haemolytic-uraemic syndrome), proteinuria, hypertension and magnesium depletion are the most common side effects. Also the risk for developing acute kidney injury in patients with advanced prostate cancer undergoing androgen deprivation therapy is discussed. © The Author 2013. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For permissions, please email: firstname.lastname@example.org.
Denies S.,Ghent University
Expert review of vaccines | Year: 2012
Tumor vaccination holds great promise for the treatment of cancer and research concerning tumor vaccination in dogs is of great interest for veterinary as well as human medicine. Indeed, cancer is the leading cause of death in adult dogs and companion animals are acknowledged as excellent preclinical models for human oncology. The license of the veterinary melanoma vaccine (Oncept™) and Provenge® for the treatment of prostate cancer in men established tumor vaccination as a valid treatment modality for cancer. Although the results with this and other vaccines are promising, there are still some hurdles to overcome. In this article, preclinical and clinical trials with tumor vaccines in dogs are discussed, as well as the surplus value of canine cancer patients for human medicine.
Joos G.F.,Ghent University
Expert Opinion on Investigational Drugs | Year: 2010
Importance of the field: The prevention and relief of symptoms by regular use of bronchodilators is central to the pharmacological management of chronic obstructive pulmonary disease (COPD). Areas covered in this review: The aim of this article is to review the effects of inhaled muscarinic antagonists in the treatment of stable COPD. What the reader will gain: An update of the clinical studies performed with the long-acting inhaled muscarinic antagonist (LAMA) tiotropium bromide in patients with COPD is given. In recent years, combinations of a LAMA and a long-acting inhaled beta2-agonist (LABA), and 'triple therapy' consisting of a LAMA, a LABA, and an inhaled steroid are being developed. Issues of safety of inhaled anticholinergics in COPD are discussed and a short overview of new LAMAs being developed for COPD is given. Take home messages: The importance of anticholinergic drug treatment in COPD was largely advanced by the development of the first LAMA, tiotropium bromide. The vast experience obtained with tiotropium bromide has paved the way for new LAMAs such as aclidinium bromide and glycopyrrolate (NVA-237). © 2010 Informa UK Ltd.
Van Der Zwan Y.G.,Rotterdam University |
Biermann K.,Rotterdam University |
Wolffenbuttel K.P.,Erasmus MC Sophia |
Cools M.,Ghent University |
Looijenga L.H.J.,Rotterdam University
European Urology | Year: 2015
Context A disturbed process of gonadal formation and maintenance may result in testicular dysgenesis syndrome or disorders of sex development (DSDs), with an increased germ cell cancer (GCC) risk. Early diagnosis and treatment requires the identification of relevant risk factors and initial pathologic stages. Objective To evaluate current knowledge and novel insights regarding GCC risk in patients with DSDs, with the aim of providing a model for clinical use. Evidence acquisition A Medline search was conducted to identify all original and review articles assessing the aetiology of GCC, GCC risk in DSD patients, new predictive markers related to GCC, and possible clinical scenarios related to GCC and DSDs. Evidence synthesis Embryonic development is controlled by orchestrated patterns of gene and subsequent protein expression. Knowledge of these networks is essential to understand the mechanisms of disturbed development including GCC formation. GCCs are subdivided into seminomas and nonseminomas, and they all arise from embryonic germ cells that have failed to mature appropriately. The precursor is known as carcinoma in situ (also referred to as testicular intratubular neoplasia and intratubular germ cell neoplasia unclassified) in a testicular microenvironment and gonadoblastoma in a dysgenetic/ovarian microenvironment. GCCs mimic embryonic development, resulting in the identification of diagnostic markers (eg, OCT3/4, SRY [sex determining region Y]-box 2 [SOX2], and [sex determining region Y]-box 17 [SOX17]). Novel insights indicate a subtle interplay of specific single nucleotide polymorphisms, environmental factors, and epigenetic aberrations in the aetiology of GCCs. A genvironmental model combining these factors is presented, proposed as a guideline for clinical management by an experienced multidisciplinary team. The goal is individualised treatment including preservation of gonadal function (if possible) and prevention of malignant transformation. Conclusions A hypothesis is presented in which combined interactions of epigenetic and environmental parameters affect embryonic gonadal development, resulting in delayed/blocked germ cell maturation that determines the risk for GCC formation. Current and future possibilities for early detection of GCCs in risk populations and follow-up in a clinical setting are discussed. Patient summary This review analyses current knowledge about the underlying networks that relate to the development of a germ cell cancer in the context of a disorder of sex development. A combined effect of epigenetic and environmental factors is identified in the pathogenesis, and a model is proposed to apply this knowledge to clinical practice. © 2014 European Association of Urology. All rights reserved.
De Graef J.,Ghent University
Parasitology | Year: 2013
Members of the ATP-binding cassette (ABC) transporter family (P-glycoproteins, Half-transporters and Multidrug Resistant Proteins) potentially play a role in the development of anthelmintic resistance. The aim of this study was to investigate the possible involvement of ABC transporters in anthelmintic resistance in the bovine parasite, Cooperia oncophora. Partial sequences of 15 members of the ABC transporter protein family were identified, by mining a transcriptome dataset combined with a degenerate PCR approach. Reverse transcriptase PCR showed that most of the ABC transporters identified were constitutively transcribed throughout the life cycle of C. oncophora. Constitutive differences in gene transcript levels between a susceptible and resistant isolate were only observed for Con-haf-9 and Con-mrp-1 in eggs of the resistant isolate, while no differences were observed in L3 or the adult life stage. Analysis of resistant adult worms, collected from calves 14 days after treatment with either ivermectin or moxidectin, showed a significant 3- to 5-fold increase in the transcript levels of Con-pgp-11 compared to non-exposed worms. Interestingly, a 4-fold transcriptional up-regulation of Con-pgp-11 was also observed in L3 of the resistant isolate, after in vitro exposure to different concentrations of ivermectin, whereas this effect was not observed in exposed L3 of the susceptible isolate. The results suggest that the worms of this particular resistant isolate have acquired the ability to up-regulate Con-pgp-11 upon exposure to macrocyclic lactones. Further work is needed to understand the genetic basis underpinning this process and the functional role of PGP-11.
Vanhaute E.,Ghent University
Journal of Peasant Studies | Year: 2011
The number of famine prone regions in the world has been shrinking for centuries. It is currently mainly limited to sub-Saharan Africa. Yet the impact of endemic hunger has not declined and the early twenty-first century seems to be faced with a new threat: global subsistence crises. In this essay I question the concepts of famine and food crisis from different analytical angles: historical and contemporary famine research, food regime theory, and peasant studies. I will argue that only a more integrated historical framework of analysis can surpass dualistic interpretations grounded in Eurocentric modernization paradigms. This article successively debates historical and contemporary famine research, the contemporary food regime and the new global food crisis, the lessons from Europe's 'grand escape' from hunger, and the peasantry and 'depeasantization' as central analytical concepts. Dualistic histories of food and famine have been dominating developmentalist stories for too long. This essay shows how a blending of historical and contemporary famine research, food regime theory and new peasant studies can foster a more integrated perspective. © 2011 Taylor & Francis.
Dhont M.,Ghent University
European Journal of Contraception and Reproductive Health Care | Year: 2010
On the 50th birthday of the pill, it is appropriate to recall the milestones which have led to its development and evolution during the last five decades. The main contraceptive effect of the pill being inhibition of ovulation, it may be called a small miracle that this drug was developed long before the complex regulation of ovulation and the menstrual cycle was elucidated. Another stumbling block on its way was the hostile climate with regard to contraception that prevailed at the time. Animal experiments on the effect of sex steroids on ovulation, and the synthesis of sex steroids and orally active analogues were the necessary preliminaries. We owe the development of oral contraceptives to a handful of persons: two determined feminists, Margaret Sanger and Katherine McCormick; a biologist, Gregory Pincus; and a gynaecologist, John Rock. Soon after the introduction of the first pills, some nasty and life-threatening side effects emerged, which were due to the high doses of sex steroids. This led to the development of new preparations with reduced oestrogen content, progestins with more specific action, and alternative administration routes. Almost every decade we have witnessed a breakthrough in oral contraception. Social and moral objections to birth control have gradually disappeared and, notwithstanding some pill scares, oral contraceptives are now one of the most used methods of contraception. Finally, all's well that ends well: recent reports have substantiated the multiple noncontraceptive health benefits paving the way for a bright future for this 50-year-old product. © 2010 The European Society of Contraception and Reproductive Health.
De Backer C.J.S.,University of Antwerp |
Hudders L.,Ghent University
Meat Science | Year: 2015
The aim of this work is to explore the relation between morality and diet choice by investigating how animal and human welfare attitudes and donation behaviors can predict a meat eating versus flexitarian versus vegetarian diet. The results of a survey study (N=299) show that animal health concerns (measured by the Animal Attitude Scale) can predict diet choice. Vegetarians are most concerned, while full-time meat eaters are least concerned, and the contrast between flexitarians and vegetarians is greater than the contrast between flexitarians and full-time meat eaters. With regards to human welfare (measured by the Moral Foundations Questionnaire), results show that attitudes towards human suffering set flexitarians apart from vegetarians and attitudes towards authority and respect distinguish between flexitarians and meat eaters. To conclude, results show that vegetarians donate more often to animal oriented charities than flexitarians and meat eaters, while no differences between the three diet groups occur for donations to human oriented charities. © 2014 Elsevier Ltd.
Finke P.A.,Ghent University
Geoderma | Year: 2012
The unique selling point of pedometricians still is close to their cradle: ability to map. Irrespective of the many scientific achievements one can ask if offering mapping ability, allbeit in various contexts, is all a pedometrician can do to bring forward soil science's broader agenda. This paper identifies, within some of the hotter issues on the soil science agenda, activities that need the input of pedometricians. Digital soil mapping (DSM) has reached maturity although some issues like the optimal use of legacy data still need attention. The necessary shift from DSM to digital soil function mapping implies an increased need for process knowledge in mapping, but also an increased focus of pedometricians on the strengthening of process models. Most quality issues related to DSM have a counterpart in process modelling, and some of these issues need elaboration to construct well-calibrated and complete models, e.g. by making motivated choices between the inclusion of processes or model reduction. Reaching out to stakeholders is also an issue of increasing interest, as these are confronted with uncertain concurrent models to evaluate future scenarios. Questions are raised such as: Does the need for a state-of-the-art (SOTA) approach imply a choice for one model and how should this be made, or is SOTA implementable as some weighted average of screened concurrent models. Can observations and model results be combined in decision making and what techniques are needed. The above issues are illustrated with existing examples and new material from soil science and beyond. As DSM and process modelling share common ground, mutual benefits can be expected at the interface of both research fields such as (i) increased usage of process knowledge in DSM and (ii) probabilistic approaches to less well understood soil processes. Stakeholders will profit from the development of decision frameworks to choose applicable DSM-techniques and the increased application of ensembles of DSM-methods and models to narrow prediction error bandwidths. Additionally, they will profit from the development of decision support systems filled with outcomes of scenario studies of multiple, uncertain, and concurrent models as these provide an interesting alternative to the application of one selected model. © 2010 Elsevier B.V.
Chernodub M.N.,University of Tours |
Chernodub M.N.,Ghent University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012
We show that the electromagnetic superconductivity of vacuum in strong magnetic field background is consistent with the Vafa-Witten theorem because the charged vector meson condensates lock relevant internal global symmetries of QCD with the electromagnetic gauge group. © 2012 American Physical Society.
Deschrijver G.,Ghent University
Information Sciences | Year: 2013
Uninorms are a generalisation of t-norms and t-conorms for which the neutral element is an element of [0, 1] which is not necessarily equal to 0 (as for t-norms) or 1 (as for t-conorms). Uninorms on the unit interval are either conjunctive or disjunctive, i.e. they aggregate the pair (0, 1) to either 0 or 1. In real-life applications, this kind of aggregation may be counter-intuitive. Interval-valued fuzzy set theory and Atanassov's intuitionistic fuzzy set theory are extensions of fuzzy set theory which allows to model uncertainty about the membership degrees. In these theories there exist uninorms which are neither conjunctive nor disjunctive. In this paper we study such uninorms more deeply and we investigate the structure of these uninorms. We also give several examples of uninorms which are neither conjunctive nor disjunctive. © 2013 Elsevier Inc. All rights reserved.
Dudal D.,Ghent University |
Sorella S.P.,State University of Rio de Janeiro
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012
An equivalent formulation of the Gribov-Zwanziger theory accounting for the gauge fixing ambiguity in the Landau gauge is presented. The resulting action is constrained by a Slavnov-Taylor identity stemming from a nilpotent exact Becchi-Rouet-Stora-Tyutin (BRST) invariance which is spontaneously broken due to the presence of the Gribov horizon. This spontaneous symmetry breaking can be described in a purely algebraic way through the introduction of a pair of auxiliary fields which give rise to a set of linearly broken Ward identities. The Goldstone sector turns out to be decoupled. The underlying exact nilpotent BRST invariance allows us to employ BRST cohomology tools within the Gribov horizon to identify renormalizable extensions of gauge invariant operators. Using a simple toy model and appropriate Dirac bracket quantization, we discuss the time evolution invariance of the operator cohomology. We further comment on the unitarity issue in a confining theory, and stress that BRST cohomology alone is not sufficient to ensure unitarity, a fact that, although well known, is frequently ignored. © 2012 American Physical Society.
Dudal D.,Ghent University |
Oliveira O.,University of Coimbra |
Rodriguez-Quintero J.,University of Huelva
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012
Either by solving the ghost propagator Dyson-Schwinger equations or through a one-loop computation in the refined Gribov-Zwanziger (RGZ) formalism, we show that a nontrivial ghost-gluon vertex is required to obtain a ghost propagator prediction compatible with the available corresponding lattice data in the SU(3) case. For the necessary gluon propagator input, we present RGZ tree-level fits which account well for the gluon lattice data. Interestingly, this propagator can be rewritten in terms of a running gluon mass. A comparison of both Dyson-Schwinger equations and RGZ results for the ghost propagator is furthermore provided. We also briefly discuss the connection between the RGZ and the operator product expansion d=2 gluon condensate. © 2012 American Physical Society.
Cousseau L.,Ghent University
Heredity | Year: 2016
Dutch house sparrow (Passer domesticus) densities dropped by nearly 50% since the early 1980s, and similar collapses in population sizes have been reported across Europe. Whether, and to what extent, such relatively recent demographic changes are accompanied by concomitant shifts in the genetic population structure of this species needs further investigation. Therefore, we here explore temporal shifts in genetic diversity, genetic structure and effective sizes of seven Dutch house sparrow populations. To allow the most powerful statistical inference, historical populations were resampled at identical locations and each individual bird was genotyped using nine polymorphic microsatellites. Although the demographic history was not reflected by a reduction in genetic diversity, levels of genetic differentiation increased over time, and the original, panmictic population (inferred from the museum samples) diverged into two distinct genetic clusters. Reductions in census size were supported by a substantial reduction in effective population size, although to a smaller extent. As most studies of contemporary house sparrow populations have been unable to identify genetic signatures of recent population declines, results of this study underpin the importance of longitudinal genetic surveys to unravel cryptic genetic patterns.Heredity advance online publication, 8 June 2016; doi:10.1038/hdy.2016.38. © 2016 The Genetics Society
Baert S.,Ghent University
Anxiety, stress, and coping | Year: 2012
Social stress has been related to both physiological and psychological responses. The recovery of stress is influenced by the way environmental information is processed, i.e., what information is attended to and how it is interpreted. The present study investigated the effect of attention modification training on physiological stress recovery following induced stress. A group of applicants preparing for a job interview were randomly allocated to an attention training condition versus a control condition. Afterwards, they were asked to give an artificial job interview to a real life jury while being videotaped. Participants in both conditions showed decreased heart rate variability during the job interview, which indicates an overall physiological stress response. However, during a 30-minute follow-up period after the training, indices of heart rate variability showed improved stress recovery only in the attention training condition. Attentional training is proposed as a promising strategy to prevent enduring stress reactions.
Saez J.C.,Pontifical Catholic University of Valparaiso |
Saez J.C.,University of Santiago de Chile |
Leybaert L.,Ghent University |
Leybaert L.,University of Santiago de Chile
FEBS Letters | Year: 2014
Connexin hemichannels (connexons) are building blocks of gap junctions but also function as free unapposed channels, which has become an active field of research. Defining functions of hemichannels and their involvement in any biological event requires ruling out possible participation of other channels that share biophysical and regulatory properties, for example pannexins, CALHM1 and P2X receptors. The lack of specific inhibitors for these channels has become an obstacle in elucidating the role of connexin hemichannels. Several experimental approaches are now available to identify hemichannels at the cell surface and to characterize their electrophysiological, permeability and regulatory properties. The use of connexin knockout/knockdown, and the development of peptides that target intracellular connexin domains and specific antibodies directed to extracellular domains have helped to dissect the role of hemichannels in endogenously expressing systems. Moreover, studies of connexin mutants in exogenous expression systems have provided convincing evidence on hemichannels in the pathogenesis of several human genetic diseases. We here present a brief overview of connexin hemichannels as functional channels and itemize a list of aspects to consider when concluding on their involvement. © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Van Meerbeeck J.P.,Ghent University |
Fennell D.A.,Queens University of Belfast |
De Ruysscher D.K.M.,Maastricht University
The Lancet | Year: 2011
The incidence and mortality of small-cell lung cancer worldwide make this disease a notable health-care issue. Diagnosis relies on histology, with the use of immunohistochemical studies to confirm difficult cases. Typical patients are men older than 70 years who are current or past heavy smokers and who have pulmonary and cardiovascular comorbidities. Patients often present with rapid-onset symptoms due to local intrathoracic tumour growth, extrapulmonary distant spread, paraneoplastic syndromes, or a combination of these features. Staging aims ultimately to define disease as metastatic or non-metastatic. Combination chemotherapy, generally platinum-based plus etoposide or irinotecan, is the mainstay first-line treatment for metastatic small-cell lung cancer. For non-metastatic disease, evidence supports early concurrent thoracic radiotherapy. Prophylactic cranial irradiation should be considered for patients with or without metastases whose disease does not progress after induction chemotherapy and radiotherapy. Despite high initial response rates, most patients eventually relapse. Except for topotecan, few treatment options then remain. Signalling pathways have been identified that might yield new drug targets. © 2011 Elsevier Ltd.
Pennings G.,Ghent University
Reproductive BioMedicine Online | Year: 2013
Several criteria are being used to restrict access to medically assisted reproduction. In many countries, parental characteristics such as age and sexual orientation are used for this purpose. Valid use of such criteria is hampered by two elements: first, there is no consensus on which features good parents should possess, and second, there is a dearth of empirical data about the effect of parental characteristics on the wellbeing of the child. The Italian Court goes even a step further: they use such criteria, in this case parental age, not only to determine eligibility for assisted reproduction but also to terminate parental rights. However, termination of parental rights can only be justified when the child is abused or when there is a high risk of serious harm. Advanced parental age does not create such a situation. © 2013, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.
Brass M.,Ghent University
Brain structure & function | Year: 2010
Cognitive neuroscience research has begun to reveal the functional neuroanatomy of intentional action. This research has primarily pointed to the role of the medial frontal cortex for the voluntary control of behaviour. However, a closer inspection of the literature reveals that the anterior insular cortex (AIC) is also routinely activated in tasks that involve different aspects of intentional action. In the present article, we outline studies that have found AIC activation in various intentional action paradigms. Based on these findings, we discuss two hypotheses about the AIC's contribution to voluntary control. One hypothesis states that AIC is involved in forming intentions, by providing information about the internal states of the system. The alternative view suggests that AIC evaluates the outcomes of intentional action decisions that have been previously formed elsewhere. The limited evidence so far favours the evaluative hypothesis. AIC may provide interoceptive signals that play an essential role in evaluating the consequences of intentional action. AIC is therefore a key structure for the adaptive, affective training of the individual will, on which human society depends.
Derave W.,Ghent University
Sports medicine (Auckland, N.Z.) | Year: 2010
Carnosine is a dipeptide with a high concentration in mammalian skeletal muscle. It is synthesized by carnosine synthase from the amino acids L-histidine and beta-alanine, of which the latter is the rate-limiting precursor, and degraded by carnosinase. Recent studies have shown that the chronic oral ingestion of beta-alanine can substantially elevate (up to 80%) the carnosine content of human skeletal muscle. Interestingly, muscle carnosine loading leads to improved performance in high-intensity exercise in both untrained and trained individuals. Although carnosine is not involved in the classic adenosine triphosphate-generating metabolic pathways, this suggests an important role of the dipeptide in the homeostasis of contracting muscle cells, especially during high rates of anaerobic energy delivery. Carnosine may attenuate acidosis by acting as a pH buffer, but improved contractile performance may also be obtained by improved excitation-contraction coupling and defence against reactive oxygen species. High carnosine concentrations are found in individuals with a high proportion of fast-twitch fibres, because these fibres are enriched with the dipeptide. Muscle carnosine content is lower in women, declines with age and is probably lower in vegetarians, whose diets are deprived of beta-alanine. Sprint-trained athletes display markedly high muscular carnosine, but the acute effect of several weeks of training on muscle carnosine is limited. High carnosine levels in elite sprinters are therefore either an important genetically determined talent selection criterion or a result of slow adaptation to years of training. beta-Alanine is rapidly developing as a popular ergogenic nutritional supplement for athletes worldwide, and the currently available scientific literature suggests that its use is evidence based. However, many aspects of the supplement, such as the potential side effects and the mechanism of action, require additional and thorough investigation by the sports science community.
Van Maldeghem H.,Ghent University
Designs, Codes, and Cryptography | Year: 2012
A symplectic polarity of a building Δ of type E 6 is a polarity whose fixed point structure is a building of type F 4 containing residues isomorphic to symplectic polar spaces. In this paper, we present two characterizations of such polarities among all dualities. Firstly, we prove that, if a duality θ of Δ never maps a point to a neighbouring symp, and maps some element to a non-opposite element, then θ is a symplectic duality. Secondly, we show that, if a duality θ never maps a chamber to an opposite chamber, then it is a symplectic polarity. The latter completes the programme for dualities of buildings of type E 6 of determining all domestic automorphisms of spherical buildings, and it also shows that symplectic polarities are the only polarities in buildings of type E 6 for which the Phan geometry is empty. © 2011 Springer Science+Business Media, LLC.
Sinnaeve D.,Ghent University
Concepts in Magnetic Resonance Part A: Bridging Education and Research | Year: 2012
The widely known Stejskal-Tanner (ST) equation is central to any diffusion NMR or so-called pulsed gradient spin-echo experiment, describing the signal attenuation due to loss of coherence caused by diffusion as a function of the experimental parameters. What is less widely known is that the equation itself is not invariable when applying different pulse sequences or different gradient pulse shapes and should thus be modified accordingly. This concept is not new, but nevertheless experimentalists applying diffusion NMR in their research often overlook or are completely oblivious to this fact. In this article, the derivation of the ST equation through the Bloch-Torrey equations is discussed in detail, followed by a discussion of the most basic NMR experiments that measure free diffusion. This derivation is performed here in a novel way, leading to expressions for the ST equation that do not assume any gradient shape beforehand, leaving only a few parameters that are determined solely by the gradient pulse shape. This new approach to presenting the ST equation increases awareness of its dependence on gradient shape. Moreover, it relieves designers of future diffusion NMR pulse sequences of struggling with the cumbersome task of deriving and reporting the equation for each gradient shape separately. A quick reference table of the ST equation for the basic diffusion NMR pulse sequences for any gradient shape is given, as well as an overview for most other diffusion NMR pulse sequences described in the literature. © 2012 Wiley Periodicals, Inc.
Chaemchuen S.,Wuhan University of Technology |
Kabir N.A.,Wuhan University of Technology |
Zhou K.,Wuhan University of Technology |
Verpoort F.,Wuhan University of Technology |
Verpoort F.,Ghent University
Chemical Society Reviews | Year: 2013
In the midst of the global climate change phenomenon, mainly caused by fossil fuel burning to provide energy for our daily life and discharge of CO2 into the atmosphere, biogas is one of the important renewable energy sources that can be upgraded and applied as a fuel source for energy in daily life. The advantages of the production of hybrid materials, metal-organic framework (MOF) adsorbents, expected for the biogas upgrading, rely on the bulk separation of CO2 under near-ambient conditions. This review highlights the challenges for MOF adsorbents, which have the greatest upgrading abilities for biogas via selective passage of methane. The key factors improving the ideal MOF materials for these high CO2 capture and selectivity uses for biogas upgrading to produce bio-methane and reduce fossil-fuel CO 2 emission will be discussed. © 2013 The Royal Society of Chemistry.
Bouyssou D.,University of Paris Dauphine |
Marchant T.,Ghent University
Journal of Informetrics | Year: 2010
Rankings of journals and rankings of scientists are usually discussed separately. We argue that a consistent approach to both rankings is desirable because both the quality of a journal and the quality of a scientist depend on the papers it/he publishes. We present a pair of consistent rankings (impact factor for the journals and total number of citations for the authors) and we provide an axiomatic characterization thereof. © 2010 Elsevier Ltd.
Willaert W.,Ghent University
Cochrane database of systematic reviews (Online) | Year: 2012
Current techniques for inguinal hernia repair show similar recurrence rates. Therefore, recurrence is no longer the main issue discussed when considering improving the current standards for groin hernia repair. Post surgical chronic pain represents a major, largely unrecognised clinical problem. Consequently, there is a need to not only decrease an extensive dissection in the inguinal canal with less manipulation of the inguinal nerves, but also to minimize the interaction between the mesh and major surrounding structures. As a result, placing the mesh in the preperitoneal space is a valuable option. To compare elective open preperitoneal mesh techniques with Lichtenstein mesh repair in terms of pain. We searched The Cochrane Central Register of Controlled Trials (The Cochrane library 2011, Issue 4), MEDLINE (January 1966 to April 2011), EMBASE (1947 to October 2009), and ISI WEB OF KNOWLEDGE (1900 to April 2011) for randomized controlled trials. The reference list of identified trials, the World Journal of Hernia and Abdominal Wall Surgery, and relevant book chapters were handsearched for useful trials. If we found relevant ongoing trials using national and international trials registers, we contacted the main investigators for further information. The language of the trials was not an exclusion criterion. Randomized controlled studies comparing elective open preperitoneal mesh techniques with Lichtenstein mesh repair. Three authors independently extracted the pre-specified data and assessed the methodological quality using domain-based evaluation. Missing information was obtained by contacting the original investigators using open-ended questions. Three eligible trials involving 569 patients were identified. Due to methodological limitations in the included studies, there was considerable variation in the results of acute (risk range 38.67% to 96.51%) and chronic pain (risk range 7.83% to 40.47%) across the control groups. Therefore, meta-analysis was not performed but the results of the outcomes in the individual trials were compared. Two trials involving 322 patients reported less chronic pain after preperitoneal repair (relative risk (RR) 0.18, number needed to treat (NNT) 8; RR 0.51, NNT 5), whereas one trial, including 247 patients, described more chronic pain after this repair (RR 1.17, NNT 77). The same trials favoured the preperitoneal technique concerning acute pain (RR 0.17, NNT 3; RR 0.78, NNT 7), whereas in the third trial it was almost omnipresent and thus comparable in both intervention arms (RR 0.997, NNT 333). Early and late hernia recurrence rates were similar across the studies, whereas contrasting results were reported for other early outcomes as infection and hematoma. No late mesh infection occurred in the included trials. Both techniques are valid as they result in similar low recurrence rates. Evaluation of pain results in the individual trials shows some evidence that preperitoneal repair causes less or comparable acute and chronic pain compared to the Lichtenstein procedure. We emphasize the need for homogeneous high quality randomized trials comparing elective preperitoneal inguinal hernia techniques and Lichtenstein repair in terms of chronic pain.
de Backer T.L.,Ghent University
Cochrane database of systematic reviews (Online) | Year: 2012
Lifestyle changes and cardiovascular prevention measures are a primary treatment for intermittent claudication (IC). Symptomatic treatment with vasoactive agents (Anatomic Therapeutic Chemical Classification (ATC) for medicines from the World Health Organisation class CO4A) is controversial. To evaluate evidence on the efficacy and safety of oral naftidrofuryl (ATC CO4 21) versus placebo on the pain-free walking distance (PFWD) of people with IC by using a meta-analysis based on individual patient data (IPD). For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched October 2012) and CENTRAL (2012, Issue 9).For the original review the authors handsearched the European Journal of Vascular and Endovascular Surgery (1984 to 1994) and checked relevant bibliographies. They contacted the registration holder of naftidrofuryl and the authors of identified trials for any unpublished data. We included only randomized controlled trials (RCTs) with low or moderate risk of bias for which the IPD were available. We collected data from the electronic data file or from the case report form and checked the data by a statistical quality control procedure. All randomized patients were analyzed following the intention-to-treat (ITT) principle. The geometric mean of the relative improvement in PFWD was calculated for both treatment groups in all identified studies.The effect of the drug was assessed compared with placebo on final walking distance (WDf) using multilevel and random-effect models and adjusting for baseline walking distance (WD0). For the responder analysis, therapeutic success was defined as an improvement of walking distance of at least 50%. We included seven studies in the IPD (n = 1266 patients). One of these studies (n = 183) was only used in the sensitivity analysis so that the main analysis included 1083 patients. The ratio of the relative improvement in PFWD (naftidrofuryl compared with placebo) was 1.37 (95% confidence interval (CI) 1.27 to 1.49, P < 0.001). The absolute difference in responder rate, or proportion successfully treated, was 22.3% (95% CI 17.1% to 27.6%). The calculated number needed to treat was 4.5 (95% CI 3.6 to 5.8). Oral naftidrofuryl has a statistically significant and clinically meaningful, although moderate, effect of improving walking distance in the six months after initiation of therapy for people with intermittent claudication. Access by researchers to data from RCTs that are suitable for IPD analysis should be possible through repositories of data from pharmacological trials. Regular formal appraisal of the balance of risk and benefit is needed for older pharmaceutical products.
Pennings G.,Ghent University
Human Reproduction | Year: 2011
Within the field of medically assisted reproduction, the welfare of the child is advanced as the major argument to decide the acceptability of certain applications. This argument, however, needs a complex framework in order to be understood and used properly. The effect of empirical evidence regarding the welfare of the child on peoples judgments about the acceptability of same-sex families will differ for utilitarians and deontologists. Deontologists who are opposed to same-sex families will not change their mind when confronted with reassuring evidence. However, utilitarians also frequently use the evidence wrongly or draw the wrong conclusions. The reasonable welfare standard is put forward to avoid counterintuitive judgments and to block comparative reasoning that may follow from the use of heterosexual families as a control in follow-up research. Finally, a number of problems related to the use of parental sexual orientation as a criterion are discussed. The discrimination against same-sex families will not be overturned by empirical evidence about the welfare of the children. Children in same-sex families are generally doing well but their situation could be improved if their parents' relationship were to be socially and legally recognized. © 2011 The Author.
Bulterijs S.,Ghent University
Rejuvenation Research | Year: 2011
Geroprotectors are drugs that decrease the rate of aging and therefore extend life span. Metformin has been described as a geroprotector, and several studies have shown that metformin can slow down the rate of aging. The mechanisms behind the geroprotective effect of metformin are less established. The goal of this review is to investigate the evidence for the geroprotective effect of metformin and to describe the possible mechanisms behind it. © 2011 Mary Ann Liebert, Inc.
Pauwels P.,Ghent University |
Terkaj W.,CNR Institute of Industrial Technologies and Automation
Automation in Construction | Year: 2016
An increasing number of information management and information exchange applications in construction industry is relying on semantic web technologies or tools from the Linked Open Data (LOD) domain to support data interoperability, flexible data exchange, distributed data management and the development of reusable tools. These goals tend to be overlapped with the purposes of the Industry Foundation Classes (IFC), which is a standard for the construction industry defined through an EXPRESS schema. A connecting point between semantic web technologies and the IFC standard would be represented by an agreed Web Ontology Language (OWL) ontology for IFC (termed ifcOWL) that allows to (1) keep on using the well-established IFC standard for representing construction data, (2) exploit the enablers of semantic web technologies in terms of data distribution, extensibility of the data model, querying, and reasoning, and (3) re-use general purpose software implementations for data storage, consistency checking and knowledge inference. Therefore, in this paper we will look into existing efforts in obtaining an ifcOWL ontology from the EXPRESS schemas of IFC and analyse which features would be required in a usable and recommendable ifcOWL ontology. In making this analysis, we present our implementations of an EXPRESS-to-OWL converter and the key features of the resulting ifcOWL ontology. © 2015 Elsevier B.V. All rights reserved.
Poels G.,Ghent University
Journal of Database Management | Year: 2011
In this paper, the author investigates the effect on understanding of using business domain models that are constructed with Resource-Event-Agent (REA) modeling patterns. First, the author analyzes REA modeling structures to identify the enabling factors and the mechanisms by means of which users recognize these structures in a conceptual model and description of an information retrieval and interpretation task. Based on this understanding, the author hypothesizes positive effects on model understanding for situations where REA patterns can be recognized in both task and model. An experiment is then conducted to demonstrate a better understanding of models with REA patterns compared to information equivalent models without REA patterns. The results of this experiment indicate that REA patterns can be recognized with minimal prior patterns training and that the use of REA patterns leads to models that are easier to understand for novice model users. Copyright © 2011, IGI Global.
Verdoolaege G.,Ghent University |
Scheunders P.,University of Antwerp
International Journal of Computer Vision | Year: 2011
We consider the Rao geodesic distance (GD) based on the Fisher information as a similarity measure on the manifold of zero-mean multivariate generalized Gaussian distributions (MGGD). The MGGD is shown to be an adequate model for the heavy-tailed wavelet statistics in multicomponent images, such as color or multispectral images. We discuss the estimation of MGGD parameters using various methods. We apply the GD between MGGDs to color texture discrimination in several classification experiments, taking into account the correlation structure between the spectral bands in the wavelet domain. We compare the performance, both in terms of texture discrimination capability and computational load, of the GD and the Kullback-Leibler divergence (KLD). Likewise, both uni- and multivariate generalized Gaussian models are evaluated, characterized by a fixed or a variable shape parameter. The modeling of the interband correlation significantly improves classification efficiency, while the GD is shown to consistently outperform the KLD as a similarity measure. © 2011 Springer Science+Business Media, LLC.
Hulpiau P.,Vlaams Institute for Biotechnology |
Van Roy F.,Vlaams Institute for Biotechnology |
Van Roy F.,Ghent University
Molecular Biology and Evolution | Year: 2011
Mining newly sequenced genomes of basal metazoan organisms reveals the evolutionary origin of modern protein families. Specific cell-cell adhesion and intracellular communication are key processes in multicellular animals, and members of the cadherin superfamily are essential players in these processes. Mammalian genomes contain over 100 genes belonging to this superfamily. By a combination of tBLASTn and profile hidden Markov model analyses, we made an exhaustive search for cadherins and compiled the cadherin repertoires in key organisms, including Branchiostoma floridae (amphioxus), the sea anemone Nematostella vectensis, and the placozoan Trichoplax adhaerens. Comparative analyses of multiple protein domains within known and novel cadherins enabled us to reconstruct the complex evolution in metazoa of this large superfamily. Five main cadherin branches are represented in the primitive metazoan Trichoplax: classical (CDH), flamingo (CELSR), dachsous (DCHS), FAT, and FAT-like. Classical cadherins, such as E-cadherin, arose from an Urmetazoan cadherin, which progressively lost N-terminal extracellular cadherin repeats, whereas its cytoplasmic domain, which binds the armadillo proteins p120ctn and β-catenin, remained quite conserved from placozoa to man. The origin of protocadherins predates the Bilateria and is likely rooted in an ancestral FAT cadherin. Several but not all protostomians lost protocadherins. The emergence of chordates coincided with a great expansion of the protocadherin repertoire. The evolution of ancient metazoan cadherins points to their unique and crucial roles in multicellular animal life. © 2010 The Author.
Lemiengre M.B.,Ghent University
Cochrane database of systematic reviews (Online) | Year: 2012
In primary care settings, the diagnosis of rhinosinusitis is generally based on clinical signs and symptoms. Technical investigations are not routinely performed, nor recommended. Individual trials show a trend in favour of antibiotics, but the balance of benefit versus harm is unclear. To assess the effect of antibiotics in adults with clinically diagnosed rhinosinusitis in primary care settings. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2012), MEDLINE (January 1950 to February week 4, 2012) and EMBASE (January 1974 to February 2012). Randomised controlled trials (RCTs) of antibiotics versus placebo in participants with rhinosinusitis-like signs or symptoms. Two authors independently extracted data and assessed the risk of bias. We contacted trial authors for additional information. We collected information on adverse effects from the trials. We included 10 trials involving 2450 participants. Overall, the risk of bias in these studies was low. Irrespective of the treatment group, 47% of participants were cured after one week and 71% after 14 days. Antibiotics can shorten the time to cure, but only five more participants per 100 will cure faster at any time point between 7 and 14 days if they receive antibiotics instead of placebo (number needed to treat to benefit (NNTB)) 18 (95% confidence interval (CI) 10 to 115, I(2) statistic 0%, eight trials). Purulent secretion resolves faster with antibiotics (odds ratio (OR) 1.58 (95% CI 1.13 to 2.22)), (NNTB 11, 95% CI 6 to 51, I(2) statistic 0%, three trials). However, 27% of the participants who received antibiotics and 15% of those who received placebo experienced adverse events (OR 2.10, 95% CI 1.60 to 2.77) (number needed to treat to harm (NNTH)) 8 (95% CI 6 to 13, I(2) statistic 13%, seven trials). More participants in the placebo group needed to start antibiotic therapy because of an abnormal course of rhinosinusitis (OR 0.49, 95% CI 0.36 to 0.66), NNTH 20 (95% CI 14 to 35, I(2) statistic 0%, eight trials). Only one disease-related complication (brain abscess) occurred in a patient treated with antibiotics. The potential benefit of antibiotics in the treatment of clinically diagnosed acute rhinosinusitis needs to be seen in the context of a high prevalence of adverse events. Taking into account antibiotic resistance and the very low incidence of serious complications, we conclude that there is no place for antibiotics for the patient with clinically diagnosed, uncomplicated acute rhinosinusitis. This review cannot make recommendations for children, patients with a suppressed immune system and patients with severe disease, as these populations were not included in the available trials.
Gibling M.R.,Dalhousie University |
Davies N.S.,Dalhousie University |
Davies N.S.,Ghent University
Nature Geoscience | Year: 2012
Fluvial landscapes diversified markedly over the 250 million years between the Cambrian and Pennsylvanian periods. The diversification occurred in tandem with the evolution of vascular plants and expanding vegetation cover. In the absence of widespread vegetation, landscapes during the Cambrian and Ordovican periods were dominated by rivers with wide sand-beds and aeolian tracts. During the late Silurian and Devonian periods, the appearance of vascular plants with root systems was associated with the development of channelled sand-bed rivers, meandering rivers and muddy floodplains. The widespread expansion of trees by the Early Pennsylvanian marks the appearance of narrow fixed channels, some representing anabranching systems, and braided rivers with vegetated islands. We conclude that the development of roots stabilized the banks of rivers and streams. The subsequent appearance of woody debris led to log jams that promoted the rapid formation of new river channels. Our contention is supported by studies of modern fluvial systems and laboratory experiments. In turn, fluvial styles influenced plant evolution as new ecological settings developed along the fluvial systems. We suggest that terrestrial plant and landscape evolution allowed colonization by an increasingly diverse array of organisms. © 2012 Macmillan Publishers Limited. All rights reserved.
Victor J.,Ghent University
The bone & joint journal | Year: 2013
We have investigated the benefits of patient specific instrument guides, applied to osteotomies around the knee. Single, dual and triple planar osteotomies were performed on tibias or femurs in 14 subjects. In all patients, a detailed pre-operative plan was prepared based upon full leg standing radiographic and CT scan information. The planned level of the osteotomy and open wedge resection was relayed to the surgery by virtue of a patient specific guide developed from the images. The mean deviation between the planned wedge angle and the executed wedge angle was 0° (-1 to 1, sd 0.71) in the coronal plane and 0.3° (-0.9 to 3, sd 1.14) in the sagittal plane. The mean deviation between the planned hip, knee, ankle angle (HKA) on full leg standing radiograph and the post-operative HKA was 0.3° (-1 to 2, sd 0.75). It is concluded that this is a feasible and valuable concept from the standpoint of pre-operative software based planning, surgical application and geometrical accuracy of outcome.
Bogaert K.,Ghent University
Urban Studies | Year: 2012
Most scholars working on the Arab World typically view the state's power as something congruent with its cartographic boundaries. Power emerges from an institutional core-the regime-which exerts its hegemony over subordinated institutions, spaces and scales. Thus, the regime presents itself as the privileged site of political formation, intervention and inquiry. The result is a body of scholarship that has largely neglected the dynamics of 'new state space' formation at the urban scale. Drawing on the case of the Bouregreg project, a massive high-end urban development scheme positioned between the twin cities of Rabat and Salé, Morocco, this paper investigates the dynamics of agency formation implicated in the creation of a new state space and considers what it reveals about state respatialisation and the rise of new governmental arrangements that have been elided by mainstream accounts on the Middle East and North African region. © 2011 Urban Studies Journal Limited.
Van Den Bosch F.,Ghent University |
Deodhar A.,Oregon Health And Science University
Best Practice and Research: Clinical Rheumatology | Year: 2014
The advent of biologics targeting tumor necrosis factor-alpha (TNFalpha) has revolutionized the field of rheumatology in general and the treatment of spondyloarthritis (SpA) in particular, since - apart from non-steroidal anti-inflammatory agents - no disease modifying treatments are available for this frequent, inflammatory rheumatic condition. The significant improvements in signs and symptoms observed with TNF-blockers in this group of diseases, have raised the bar with regard to treatment goals, including clinical remission. Even if treatment failure with TNF-blocking agents may be a relatively rare phenomenon, cases of primary non-responders, secondary loss-of-efficacy and intolerance, have been described. Results with abatacept, rituximab and tocilizumab - all effective in the treatment of rheumatoid arthritis - were disappointing, especially in patients that had previously failed anti-TNF therapy. On the other hand, there is increasing evidence that targeting the cytokines of the Th-17 axis is associated with major improvements of skin psoriasis and its associated arthritis. In axial spondyloarthritis, preliminary proof-of-concept studies with ustekinumab and interleukin-17 targeting therapies suggest that these agents could become the first new treatment options, not targeting TNF. Finally, the advent of small molecules targeting inflammatory, intracellular signalling pathways, may further change our future therapeutic approach. © 2014 Elsevier Ltd. All rights reserved.
Pennings G.,Ghent University
Gynecologie Obstetrique Fertilite | Year: 2013
The term "social freezing" is used to degrade the reason for freezing eggs to the level of a wish instead of a need. The main problem is that the distinction between "social" and "medical" freezing is very difficult to make and many applications do not fit nicely into one of the categories. The rejection of these applications also suffers from a number of inconsistencies. Given the difficulties in separating the two models, it is proposed that all applications, regardless of the reason, should be evaluated with the same criteria: efficiency, safety and justice. © 2013 Elsevier Masson SAS.
De Bie H.,Ghent University
Mathematical Methods in the Applied Sciences | Year: 2012
In this review, we give an overview of several recent generalizations of the Fourier transform, related to either the Lie algebra sl2 or the Lie superalgebra osp(1|2). In the former case, one obtains scalar generalizations of the Fourier transform, including the fractional Fourier transform, the Dunkl transform, the radially deformed Fourier transform, and the super Fourier transform. In the latter case, one has to use the framework of Clifford analysis and arrives at the Clifford-Fourier transform and the radially deformed hypercomplex Fourier transform. A detailed exposition of all these transforms is given, with emphasis on aspects such as eigenfunctions and spectrum of the transform, characterization of the integral kernel, and connection with various special functions. Copyright © 2012 John Wiley & Sons, Ltd.
Van Dyck D.,Ghent University
Health education research | Year: 2013
The study aim was to investigate the health effects of a pedometer-based behavioural modification program in type 2 diabetes patients and to examine the relationship between changes in steps/day (baseline-post and baseline-follow up) and health outcomes. Ninety-two type 2 diabetes patients (69% male, mean age: 62 ± 9 years and mean BMI: 30.0 ± 2.5 kg/m(2)) were recruited and randomly assigned to an intervention or control group. The intervention consisted of one face-to-face session, pedometer use and seven telephone calls. Selection criteria included 35-75 years, 25-35 kg/m(2) and ≤12% HbA1c (108 mmol/mol). Outcome measures were assessed at baseline, post and follow up, and included systolic blood pressure, waist circumference, body mass index, glucose control (HbA1c and fasting glucose), triglycerides, total, HDL and LDL cholesterol and steps/day. The results showed no significant short- or intermediate-term differences in health outcomes between the control and intervention group. However, a threshold was identified, as HbA1c improved significantly in those who increased ≥4000 steps/day between baseline- and post-measurements (n = 18). This threshold was not applicable to any other health outcome. Hence, although the intervention successfully increased steps/day, no direct effect on health outcomes was identified. However, an increase of ≥4000 steps/day seemed a threshold to have a positive impact on HbA1c.
Vandierendonck A.,Ghent University
Frontiers in Human Neuroscience | Year: 2014
The notion of working memory (WM) was introduced to account for the usage of shortterm memory resources by other cognitive tasks such as reasoning, mental arithmetic, language comprehension, and many others. This collaboration between memory and other cognitive tasks can only be achieved by a dedicated WM system that controls task coordination. To that end, WM models include executive control. Nevertheless, other attention control systems may be involved in coordination of memory and cognitive tasks calling on memory resources. The present paper briefly reviews the evidence concerning the role of selective attention in WM activities. A model is proposed in which selective attention control is directly linked to the executive control part of the WM system. The model assumes that apart from storage of declarative information, the system also includes an executive WM module that represents the current task set. Control processes are automatically triggered when particular conditions in these modules are met. As each task set represents the parameter settings and the actions needed to achieve the task goal, it will depend on the specific settings and actions whether selective attention control will have to be shared among the active tasks. Only when such sharing is required, task performance will be affected by the capacity limits of the control system involved. © 2014 Vandierendonck.
Devolder K.,Ghent University
American Journal of Bioethics | Year: 2015
Shortly before and during the Second World War, Japanese doctors and medical researchers conducted large-scale human experiments in occupied China that were at least as gruesome as those conducted by Nazi doctors. Japan never officially acknowledged the occurrence of the experiments, never tried any of the perpetrators, and never provided compensation to the victims or issued an apology. Building on work by Jing-Bao Nie, this article argues that the U.S. government is heavily complicit in this grave injustice, and should respond in an appropriate way in order to reduce this complicity, as well as to avoid complicity in future unethical medical experiments. It also calls on other U.S. institutions, in particular the Presidential Commission for the Study of Bioethical Issues, to urge the government to respond, or to at least inform the public and initiate a debate about this dark page of American and Japanese history. © 2015, Copyright © Taylor & Francis Group, LLC.
Mueller S.C.,Ghent University
Journal of Neuroendocrinology | Year: 2013
Mounting magnetic resonance imaging (MRI) research is characterising the neurobiological trajectories of healthy human brain development. In parallel, studies increasingly acknowledge the relevance of perturbations of these trajectories for adolescent and adult psychopathology. Although an influence of steroid hormones on mood and anxiety disorders has been demonstrated in adults, very little is known about how steroid hormones alter human brain development and contribute to adolescent psychopathology. This review focuses on recent evidence obtained from structural and functional MRI in children and adolescents with genetic endocrine disorders and with characteristic fluctuations in androgen or oestrogen levels (familial male precocious puberty, congenital adrenal hyperplasia, Klinefelter syndrome and Turner syndrome). It aims to highlight how neurobiological findings from these paediatric endocrine disorders can provide insight into the contribution of sex steroids with respect to the development of neurocircuitry involved in affective processing (amygdala, hippocampus) and cognitive control (prefrontal cortex, inferior frontal gyrus, striatum). In addition, findings from these populations may also provide important information on aberrant psychological processes relevant for the clinical care and management of these populations. Finally, the findings are discussed within the context of current frameworks in animal models, such as the organisational-activational hypothesis or the aromatisation hypothesis. The review ends with a discussion of open questions for future enquiry with the goal of integrating translational models with current knowledge of endocrine disorders and developmental studies in healthy populations. © 2013 British Society for Neuroendocrinology.
Van Damme E.J.M.,Ghent University
Advances in Experimental Medicine and Biology | Year: 2011
In recent years, evidence has been accumulating that protein-carbohydrate interactions play an important role in host-pathogen interaction(s), development, cell-cell communication, and cell signaling. To study the protein-carbohydrate recognition phenomena that take place within or at the surface of a cell, it is requisite to have the appropriate tools for dissecting this type of interaction. During the past decade, microarray technology has successfully been introduced into the field of glycobiology. These carbohydrate or glycan microarrays allow the rapid and comprehensive screening of carbohydrate-binding proteins for interaction with a large set of carbohydrate structures and characterization of their carbohydrate-binding properties. © 2011 Springer Science+Business Media, LLC.
Courtens E.N.P.,Ghent University
ISME Journal | Year: 2016
The increasing production of nitrogen-containing fertilizers is crucial to meet the global food demand, yet high losses of reactive nitrogen associated with the food production/consumption chain progressively deteriorate the natural environment. Currently, mesophilic nitrogen-removing microbes eliminate nitrogen from wastewaters. Although thermophilic nitrifiers have been separately enriched from natural environments, no bioreactors are described that couple these processes for the treatment of nitrogen in hot wastewaters. Samples from composting facilities were used as inoculum for the batch-wise enrichment of thermophilic nitrifiers (350 days). Subsequently, the enrichments were transferred to a bioreactor to obtain a stable, high-rate nitrifying process (560 days). The community contained up to 17% ammonia-oxidizing archaea (AOAs) closely related to ‘Candidatus Nitrososphaera gargensis’, and 25% nitrite-oxidizing bacteria (NOBs) related to Nitrospira calida. Incorporation of 13C-derived bicarbonate into the respective characteristic membrane lipids during nitrification supported their activity as autotrophs. Specific activities up to 198±10 and 894±81 mg N g-1 VSS per day for AOAs and NOBs were measured, where NOBs were 33% more sensitive to free ammonia. The NOBs were extremely sensitive to free nitrous acid, whereas the AOAs could only be inhibited by high nitrite concentrations, independent of the free nitrous acid concentration. The observed difference in product/substrate inhibition could facilitate the development of NOB inhibition strategies to achieve more cost-effective processes such as deammonification. This study describes the enrichment of autotrophic thermophilic nitrifiers from a nutrient-rich environment and the successful operation of a thermophilic nitrifying bioreactor for the first time, facilitating opportunities for thermophilic nitrogen removal biotechnology.The ISME Journal advance online publication, 19 February 2016; doi:10.1038/ismej.2016.8. © 2016 International Society for Microbial Ecology
De Bosscher K.,Ghent University
Journal of Steroid Biochemistry and Molecular Biology | Year: 2010
The ancient two-faced Roman god Janus is often used as a metaphor to describe the characteristics of the Glucocorticoid Receptor (NR3C1), which exhibits both a beneficial side, that serves to halt inflammation, and a detrimental side responsible for undesirable effects. However, recent developments suggest that the Glucocorticoid Receptor has many more faces with the potential to express a range of different functionalities, depending on factors that include the tissue type, ligand type, receptor variants, cofactor surroundings and target gene promoters. This behavior of the receptor has made the development of safer ligands, that trigger the expression program of only a desirable subset of genes, a real challenge. Thus more knowledge-based fundamental research is needed to ensure the design and development of selective Glucocorticoid Receptor modulators capable of reaching the clinic. Recent advances in the characterization of novel selective Glucocorticoid Receptor modulators, specifically in the context of anti-inflammatory strategies, will be described in this review. © 2010 Elsevier Ltd.
Vansteelandt S.,Ghent University |
Lange C.,Harvard University
Human Genetics | Year: 2012
Over the past three decades, substantial developments have been made on how to infer the causal effect of an exposure on an outcome, using data from observational studies, with the randomized experiment as the golden standard. These developments have reshaped the paradigm of how to build statistical models, how to adjust for confounding, how to assess direct effects, mediated effects and interactions, and even how to analyze data from randomized experiments. The congruence of random transmission of alleles during meiosis and the randomization in controlled experiments/trials, suggests that genetic studies may lend themselves naturally to a causal analysis. In this contribution, we will reflect on this and motivate, through illustrative examples, where insights from the causal inference literature may help to understand and correct for typical biases in genetic effect estimates. © Springer-Verlag 2012.
Dewitte M.,Ghent University |
Dewitte M.,Maastricht University
Archives of Sexual Behavior | Year: 2015
The present study investigated the specificity of sexual appraisal processes by making a distinction between implicit and explicit appraisals and between the affective (liking) and motivational (wanting) valence of sexual stimuli. These appraisals are assumed to diverge between men and women, depending on the context in which the sexual stimulus is encountered. Using an Implicit Association Test, explicit ratings, and film clips to prime a sexual, romantic or neutral motivational context, we investigated whether liking and wanting of sexual stimuli differed at the implicit and explicit level, differed between men and women, and were differentially sensitive to context manipulations. Results showed that, at the implicit level, women wanted more sex after being primed with romantic mood whereas men showed the least wanting of sex in the romantic condition. At the explicit level, men reported greater liking and wanting of sex than women, independently of context. We also found that women’s (self-reported) sexual behavior was best predicted by the incentive salience of sexual stimuli whereas men’s sexual behavior was more closely related to the hedonic qualities of sexual stimuli. Results were discussed in relation to an emotion-motivational account of sexual functioning. © 2014, Springer Science+Business Media New York.
Vandeweghe S.,Ghent University
European journal of oral implantology | Year: 2012
To evaluate whether platform switching could preserve marginal bone around implants up to 6 months after loading. 15 patients were selected for a randomised controlled trial. Each patient received one customised wide body implant, with the external hex connection located eccentrically, allowing an extra 1 mm switch on one side. The hex was positioned at random at the mesial or distal side and the implant was loaded after 6 months of non-submerged healing. Patients were examined at 3, 6 and 12 months after surgery, during which a radiograph was taken to evaluate bone levels. At 12 months, the mucosal thickness was measured using a perio-probe. All implants survived and the mean overall bone loss, calculated from both the switched and non-switched side, was 0.39 mm (SD 0.33, range 0.00-1.45), 0.85 mm (SD 0.59, range 0.10-2.50) and 0.80 mm (SD 0.46, 0.26-1.89) after 3, 6 and 12 months, respectively. The bone loss continued up to 6 months but stabilised thereafter (P = 0.615). Significantly more bone loss was observed at the non-switched side compared to the switched side at 3 months (0.51 mm versus 0.28 mm, P = 0.019), 6 months (1.05 mm versus 0.64 mm, P = 0.002) and 12 months (0.94 mm versus 0.66 mm, P = 0.002). The mean mucosal thickness was 4.22 mm (SD 1.45; range 1.50-7.00), and was not significantly different between the switched and non-switched sides (P = 0.882). However, using a post-hoc analysis with the mean thickness as a threshold, the mean bone loss was only significantly different between switched and non-switched sides when the mucosa was thicker than 4.22 mm (P = 0.036). The outcome of this randomised trial is in accordance with earlier studies suggesting that that platform switching decreases bone loss by 30%. Although the sample size was limited, it seems that the creation of a biologic width affects peri-implant bone loss to a significant extent and that platform switching is only effective when the mucosal thickness allows the establishment of a biologic width.
De Boeck H.J.,University of Antwerp |
Verbeeck H.,Ghent University
Biogeosciences | Year: 2011
Drought periods can have important impacts on plant productivity and ecosystem functioning, but climatic conditions other than the lack of precipitation during droughts have never been quantified and have therefore not been considered explicitly in both experimental and modeling studies. Here, we identify which climatic characteristics deviate from normal during droughts and how these deviations could affect plant responses. Analysis of 609 years of daily data from nine Western European meteorological stations reveals that droughts in the studied region are consistently associated with more sunshine (+45 %), increased mean (+1.6 °C) and maximum (+2.8 °C) air temperatures and vapour pressure deficits that were 51 % higher than under normal conditions. These deviations from normal increase significantly as droughts progress. Using the process-model ORCHIDEE, we simulated droughts consistent with the results of the dataset analysis and compared water and carbon exchange of three different vegetation types during such natural droughts and droughts in which only the precipitation was affected. The comparison revealed contrasting responses: carbon loss was higher under natural drought in grasslands, while increased carbon uptake was found especially in decidious forests. This difference was attributed to better access to water reserves in forest ecosystems which prevented drought stress. This demonstrates that the warmer and sunnier conditions naturally associated with droughts can either improve growth or aggravate drought-related stress, depending on water reserves. As the impacts of including or excluding climatic parameters that correlate with drought are substantial, we propose that both experimental and modeling efforts should take into account other environmental factors than merely precipitation. © 2011 Author(s).
Deschrijver G.,Ghent University
Fuzzy Sets and Systems | Year: 2011
In this paper we study t-norms on the lattice of closed subintervals of the unit interval. Unlike for t-norms on a product lattice for which there exists a straightforward characterization of t-norms which are join-morphisms, respectively meet-morphisms, the situation is more complicated for t-norms in interval-valued fuzzy set theory. In previous papers several characterizations were given of t-norms in interval-valued fuzzy set theory which are join-morphisms and which satisfy additional properties, but little attention has been paid to meet-morphisms. Therefore, in this paper, we focus on t-norms which are meet-morphisms. We consider a general class of t-norms and investigate under which conditions t-norms belonging to this class are meet-morphisms. We also characterize the t-norms which are both a join- and a meet-morphism and which satisfy an additional border condition. © 2011 Elsevier B.V. All rights reserved.
De Bruyn B.,Ghent University
European Journal of Combinatorics | Year: 2011
We characterize the hyperplanes of the dual polar space DW(2n-1,q) which arise from projective embeddings as those hyperplanes H of DW(2n-1,q) which satisfy the following property: if Q is an ovoidal quad, then Q ∩ H is a classical ovoid of Q. A consequence of this is that all hyperplanes of the dual polar spaces DW(2n-1,4), DW(2n-1,16) and DW(2n-1, p) (p prime) arise from projective embeddings. © 2011 Elsevier Ltd.
Vandamme P.,Laboratory of Microbiology