Showing papers by "Ghent University published in 1996"
TL;DR: This biennial Review summarizes much of particle physics, using data from previous editions.
12,798 citations
TL;DR: In this review, the practice of polyphasic taxonomy is discussed for four groups of bacteria chosen for their relevance, complexity, or both: the genera Xanthomonas and Campylobacter, the lactic acid bacteria, and the family Comamonadaceae.
1,651 citations
TL;DR: More stringent requirements for diagnosis of the Marfan syndrome in relatives of an unequivocally affected individual; skeletal involvement as a major criterion if at least 4 of 8 typical skeletal manifestations are present; and potential contribution of molecular analysis to the diagnosis of Marfan Syndrome are proposed.
Abstract: In 1986, the diagnosis of the Marfan syndrome was codified on the basis of clinical criteria in the Berlin nosology [Beighton et al., 1988]. Over time, weaknesses have emerged in these criteria, a problem accentuated by the advent of molecular testing. In this paper, we propose a revision of diagnostic criteria for Marfan syndrome and related conditions. Most notable are: more stringent requirements for diagnosis of the Marfan syndrome in relatives of an unequivocally affected individual; skeletal involvement as a major criterion if at least 4 of 8 typical skeletal manifestations are present; potential contribution of molecular analysis to the diagnosis of Marfan syndrome; and delineation of initial criteria for diagnosis of other heritable conditions with partially overlapping phenotypes.
1,541 citations
TL;DR: A panel of four 16S rRNA-targeted oligonucleotide probes specific for bacteria of the phylum cytophaga-flavobacter-bacteroides (CFB) were designed and used together with other higher-order probes to analyse the structure and community composition in complex environments.
Abstract: We designed a panel of four 16S rRNA-targeted oligonucleotide probes specific for bacteria of the phylum cytophaga-flavobacter-bacteroides (CFB). Probes CF319a and CF319b are targeted to members of the flavobacteria-cytophaga group and the genus Porphyromonas, whereas probe BAC303 has a target region characteristic for the genera Prevotella and Bacteroides within the bacteroides group. The probe FFE8b was developed for species-specific hybridizations with Flavobacterium ferrugineum. All probes were designed by computer-assisted sequence analysis and compared to all currently accessible 16S and 23S rRNA sequences. The oligonucleotides were further evaluated by whole-cell and non-radioactive dot-blot hybridization against reference strains of the CFB phylum and other major lineages of Bacteria. The newly developed probes were used together with other higher-order probes to analyse the structure and community composition in complex environments. In activated sludge samples, members of the flavobacteria-cytophaga group were revealed by in situ hybridization as important constituents of sludge flocs and characteristic colonizers of filamentous bacteria. By application of fluorescent probe BAC303, members of the genera Bacteroides and Prevotella could be visualized without prior cultivation as an important part of the human faecal microflora.
1,220 citations
TL;DR: In this paper, the authors examined the determinants of interaction between VCs and CEOs, the roles VCs assume, and VCs' perceptions of how much value they add through these roles.
880 citations
TL;DR: It is shown that the new method is able to find a donor site in the coding sequence for the jelly fish Green Fluorescent Protein, exactly at the position that was experimentally observed in A.thaliana transformants.
Abstract: Artificial neural networks have been combined with a rule based system to predict intron splice sites in the dicot plant Arabidopsis thaliana. A two step prediction scheme, where a global prediction of the coding potential regulates a cutoff level for a local prediction of splice sites, is refined by rules based on splice site confidence values, prediction scores, coding context and distances between potential splice sites. In this approach, the prediction of splice sites mutually affect each other in a non-local manner. The combined approach drastically reduces the large amount of false positive splice sites normally haunting splice site prediction. An analysis of the errors made by the networks in the first step of the method revealed a previously unknown feature, a frequent T-tract prolongation containing cryptic acceptor sites in the 5' end of exons. The method presented here has been compared with three other approaches, GeneFinder, Gene-Mark and Grail. Overall the method presented here is an order of magnitude better. We show that the new method is able to find a donor site in the coding sequence for the jelly fish Green Fluorescent Protein, exactly at the position that was experimentally observed in A.thaliana transformants. Predictions for alternatively spliced genes are also presented, together with examples of genes from other dicots, monocots and algae. The method has been made available through electronic mail (NetPlantGene@cbs.dtu.dk), or the WWW at http://www.cbs.dtu.dk/NetPlantGene.html
810 citations
TL;DR: It is found that type-D personality was a significant predictor of long-term mortality in patients with established CHD, independently of biomedical risk factors.
625 citations
TL;DR: Comparison of the newly obtained data with results previously obtained by well-established genotypic and chemotaxonomic methods shows the superior discriminative power of AFLP towards the differentiation of highly related bacterial strains that belong to the same species or even biovar (i.e. to characterize strains at the infrasubspecific level).
Abstract: We investigated the usefulness of a novel DNA fingerprinting technique, AFLP, which is based on the selective amplification of genomic restriction fragments by PCR, to differentiate bacterial strains at the subgeneric level. In total, 147 bacterial strains were subjected to AFLP fingerprinting: 36 Xanthomonas strains, including 23 pathovars of Xanthomonas axonopodis and six pathovars of Xanthomonas vasicola, one strain of Stenotrophomonas, 90 genotypically characterized strains comprising all 14 hybridization groups currently described in the genus Aeromonas, and four strains of each of the genera Clostridium, Bacillus, Acinetobacter, Pseudomonas and Vibrio. Depending on the genus, total genomic DNA of each bacterium was digested with a particular combination of two restriction endonucleases and the resulting fragments were ligated to restriction halfsite-specific adaptors. These adaptors served as primer-binding sites allowing the fragments to be amplified by selective PCR primers that extend beyond the adaptor and restriction site sequences. Following electrophoretic separation on 5% (w/v) polyacrylamide/8.3 M urea, amplified products could be visualized by autoradiography because one of the selective primers was radioactively labelled. The resulting banding patterns, containing approximately 30-50 visualized PCR products in the size range 80-550 bp, were captured by a high-resolution densitoscanner and further processed for computer-assisted analysis to determine band-based similarity coefficients. This study reveals extensive evidence for the applicability of AFLP in bacterial taxonomy through comparison of the newly obtained data with results previously obtained by well-established genotypic and chemotaxonomic methods such as DNA-DNA hybridization and cellular fatty acid analysis. In addition, this study clearly demonstrates the superior discriminative power of AFLP towards the differentiation of highly related bacterial strains that belong to the same species or even biovar (i.e. to characterize strains at the infrasubspecific level), highlighting the potential of this novel fingerprinting method in epidemiological and evolutionary studies.
561 citations
TL;DR: In this paper, a steady-state kinetic model for methanol synthesis and the water gas shift reaction on a commercial Cu/ZnO/Al2O3 catalyst is presented.
544 citations
Journal Article•
TL;DR: Evidence is provided that frequent E-cadherin mutations are involved in the particular etiology of sporadic lobular breast cancers and in 0 of 50 breast cancers of other histopathological subtypes.
Abstract: We have analysed a series of 49 human breast cancers for mutations in the entire coding region plus flanking intron sequences of the E-cadherin gene. The tumours included 41 infiltrating lobular carcinomas, two infiltrating ducto-lobular carcinomas and six infiltrative ductal carcinomas. In the lobular carcinomas 23 different somatic mutations were detected, of which seven were insertions, 11 deletions, two nonsense mutations and three splice site mutations. The other tumours showed no detectable E-cadherin mutations. All the frameshift and nonsense mutations are expected to generate a secreted E-cadherin fragment instead of a transmembrane protein with cell adhesion activity. The majority of the mutations (21 of 23) were found in combination with loss of heterozygosity of the wild type E-cadherin locus (16q22.1), a hallmark of classical tumour suppressor genes. The mutations were scattered over the whole coding region and no hot spots could be identified. All mutations described here were previously unreported. In conclusion, we have identified up to now E-cadherin mutations in 27 of 48 (56%) infiltrating lobular breast carcinomas and in 0 of 50 breast cancers of other histopathological subtypes. These data provide strong evidence that frequent E-cadherin mutations are involved in the particular etiology of sporadic lobular breast cancers.
455 citations
TL;DR: In this article, the authors examined the performance effects of acquisitions and mergers between EC credit institutions over the period 1988-1993 and found that domestic mergers among equal-sized partners significantly increase the performance of the merged banks.
Abstract: Based on a sample of 492 takeovers we examine the performance effects of acquisitions and mergers between EC credit institutions over the period 1988–1993. The sample is subdivided according to the degree of managerial leverage on the part of the acquirer and the degree of operational integration. The results indicate that domestic mergers among equal-sized partners significantly increase the performance of the merged banks. Improvement of cost efficiency is also found in cross-border acquisitions. On the other hand, domestic takeovers are found to be influenced predominantly by defensive and managerial motives such as size maximization.
TL;DR: The influence of age, smoking, body mass index (BMI), serum albumin, insulin, GH, and insulin-like growth factor I (IGF-I) levels, respectively, on androgen levels and SHBG-binding capacity in a nonobese healthy population as well as in an obese population before and after weight loss is investigated.
Abstract: Several aspects of the regulation of androgen secretion and plasma levels in males remain controversial. Among these, we cite the problem of whether the age-related decrease in testosterone (T) levels is an intrinsic aging phenomenon or is a sequel of previous illness, the mechanisms underlying the increase in sex hormone-binding globulin (SHBG)-binding capacity in aging men and the supranormal capacity observed immediately after a weight-reducing diet, and the role of insulin in the age-associated decrease in dehydroepiandrosterone (sulfate) [DHEA (DHEAS)] levels. To gain further insight into these issues, we investigated the influence of age, smoking, body mass index (BMI), serum albumin, insulin, GH, and insulin-like growth factor I (IGF-I) levels, respectively, on androgen levels and SHBG-binding capacity in a nonobese healthy population (n = 250) as well as in an obese population (n = 50) before and after weight loss. The influence of GH supplementation on SHBG, DHEAS, DHEA, and insulin levels was st...
TL;DR: In this article, the authors examined the fatty acid composition of serum cholesteryl esters and phospholipids in 36 major depressed, 14 minor depressed and 24 normal subjects.
TL;DR: A chimeric gene consisting of the coding sequence for chloroplastic Fe superoxide dismutase from Arabidopsis thaliana coupled to the chloroplast targeting sequence from the pea ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit was expressed in Nicotiana tabacum cv Petit Havana SR1.
Abstract: A chimeric gene consisting of the coding sequence for chloroplastic Fe superoxide dismutase (FeSOD) from Arabidopsis thaliana, coupled to the chloroplast targeting sequence from the pea ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit, was expressed in Nicotiana tabacum cv Petit Havana SR1. Expression of the transgenic FeSOD protected both the plasmalemma and photosystem II against superoxide generated during illumination of leaf discs impregnated with methyl viologen. By contrast, overproduction of a mitochondrial MnSOD from Nicotiana plumbaginifolia in the chloroplasts of cv SR1 protected only the plasmalemma, but not photosystem II, against methyl viologen (L. Slooten, K. Capiau, W. Van Camp, M. Van Montagu, C. Sybesma, D. Inze [1995] Plant Physiol 107: 737-750). The difference in effectiveness correlates with different membrane affinities of the transgenic FeSOD and MnSOD. Overproduction of FeSOD does not confer tolerance to H2O2, singlet oxygen, chilling-induced photoinhibition in leaf disc assays, or to salt stress at the whole plant level. In nontransgenic plants, salt stress led to a 2- to 3-fold increase in activity, on a protein basis, of FeSOD, cytosolic and chloroplastic Cu/ZnSOD, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. In FeSOD-overproducing plants under salt stress, the induction of cytosolic and chloroplastic Cu/ZnSOD was suppressed, whereas induction of a water-soluble chloroplastic ascorbate peroxidase isozyme was promoted.
TL;DR: In this article, the authors discuss the role of charged dust in the formation of planetary rings, including radial spokes in the B-ring and braids in the F-ring of Saturn.
Abstract: Astrophysical dust occurs in many circumstances, like interstellar and circumstellar media, and between and around planets and comets. Typical Solar System applications include planetary rings, asteroid zones, cometary comae and tails, and regions of Earth's lower magnetosphere. Dust grains immersed in ambient plasmas are electrically charged by various processes and interact with electromagnetic fields. Intriguing phenomena observed in the 1980s by Voyager cameras and attributed to charged dust are radial spokes in the B-ring and braids in the F-ring of Saturn. Collective effects become important when the dust intergrain distance is smaller than the plasma Debye length, and start from observations that micron-sized dust grains can have very high negative charges and in proportion even higher masses. Characteristic dust frequencies are considerably smaller than corresponding electron or ion quantities, giving rise to new low-frequency eigenmodes, which could explain some of the low-frequency noise in space and astrophysical plasmas. Repelling electrostatic forces between charged dust grains prevent planetary rings from collapsing to very thin sheets, and oscillations in transverse ring thickness give rise to resonant phenomena, held responsible for gaps in the rings of Jupiter and Saturn. Further features are connected with fluctuating dust charges, which imply highly nontrivial source and/or sink terms in the description, and those in turn lead to new electrostatic and electromagnetic instabilities. Many different papers are reviewed which discuss waves and instabilities in dusty space plasmas, both with fixed and variable dust charges, at the linear level and, at the nonlinear level, involving double layers, solitons, vortices and other waves. These studies are at present far ahead of what observations can corroborate, a situation not likely to change soon due to the paucity of coming solar system missions concerned with planetary or cometary phenomena.
TL;DR: In this article, a degree of hydration-based description for the compressive strength, Young's modulus, uniaxial tensile strength, splitting tensile and flexural tensile strengths, Poisson's ratio and peak strain are all worked out based on an extensive experimental program on hardening concrete elements.
Abstract: For the evaluation of the risk of thermal cracking in hardening massive concrete elements, knowledge of the development of strength and deformability of early-age concrete is extremely important. Based on an extensive experimental research program on hardening concrete elements, a degree of hydration-based description for the compressive strength, Young's modulus, the uniaxial tensile strength, the splitting tensile strength, the flexural tensile strength, Poisson's ratio and the peak strain are all worked out. An extension of the formulation of Sargin for the stress-strain relation for short-term compressive loading leads to a degree of hydration-based stress-strain relation for hardening concrete. Good agreement with experimental results is reported.
TL;DR: In this article, seven regionally correlatable reflectors have been identified in the Upper Cenozoic sedimentary succession along the western continental margin of Svalbard and the Barents Sea.
TL;DR: The complete β-tubulin folding pathway was described in this article, where the postchaperonin steps in the reaction cascade do not depend on ATP or GTP hydrolysis, although GTP plays a structural role in tubulin folding.
TL;DR: Because ARDRA detects interspecies and interstrain as well as interoperon variability and enables a relatively fast multiple strain analysis per taxon, this technique is appropriate to obtain indicative phylogenetic and taxonomic information.
TL;DR: It can be concluded that drastic inhibition of methane production is not unequivocally successful as a result of several factors, such as: instantaneous inhibition often followed by restoration of methanogenesis due to adaptation of the microbes or degradation of the additive, toxicity for the host animal, negative effects on overall digestion and productive performance.
Abstract: During the last decades, considerable research on methane production in the rumen and its inhibition has been carried out. Initially, as methane production represents a significant loss of gross energy in the feed (2–15%), the ultimate goal of such intervention in rumen fermentation was an increase in feed efficiency. A second reason favouring research on methane inhibition is its role in the global warming phenomenon and in the destruction of the ozone layer. In this review, the authors describe briefly several interventions for reducing methane emission by ruminants. The objective can be reached by intervention at the dietary level by ration manipulation (composition, feeding level) or by the use of additives or supplements. Examples of additives are polyhalogenated compounds, ionophores and other antibiotics. Supplementation of the ration with lipids also lowered methanogenesis. More biotechnological interventions, e.g., defaunation, probiotics and introduction of reductive acetogenesis in the rumen, are also mentioned. It can be concluded that drastic inhibition of methane production is not unequivocally successful as a result of several factors, such as: instantaneous inhibition often followed by restoration of methanogenesis due to adaptation of the microbes or degradation of the additive, toxicity for the host animal, negative effects on overall digestion and productive performance. Therefore, methanogenesis and its inhibition cannot be considered as a separate part of rumen fermentation and its consequences on the animal should be taken into account.
TL;DR: The most important results obtained in this study are presented, and are extended to the case of plant D-type cyclins, in which three groups are identified.
Abstract: The comparative analysis of a large number of plant cyclins of the A/B family has recently revealed that plants possess two distinct B-type groups and three distinct A-type groups of cyclins [1]. Despite earlier uncertainties, this large-scale comparative analysis has allowed an unequivocal definition of plant cyclins into either A or B classes. We present here the most important results obtained in this study, and extend them to the case of plant D-type cyclins, in which three groups are identified. For each of the plant cyclin groups, consensus sequences have been established and a new, rational, plant-wide naming system is proposed in accordance with the guidelines of the Commission on Plant Gene Nomenclature. This nomenclature is based on the animal system indicating cyclin classes by an upper-case roman letter, and distinct groups within these classes by an arabic numeral suffix. The naming of plant cyclin classes is chosen to indicate homology to their closest animal class. The revised nomenclature of all described plant cyclins is presented, with their classification into groups CycA1, CycA2, CycA3, CycB1, CycB2, CycD1, CycD2 and CycD3.
TL;DR: In this article, a Ni-catalyst-based Adiabatic fixed-bed this article with a catalytic combustion zone fed with methane/oxygen or methane/air mixtures was simulated based upon the kinetics of total combustion, steam reforming and water-gas shift on a Ni catalyst.
Abstract: The modeling and simulation of reactors for the catalytic partial oxidation of natural gas to synthesis gas is complex and requires detailed kinetics if it is to be representative and reliable. Adiabatic fixed bed reactors with a catalytic combustion zone fed with methane/oxygen or methane/air mixtures were simulated based upon the kinetics of total combustion, steam reforming and water-gas shift on a Ni catalyst. The steam reforming reactions and water-gas shift reaction are parallel or more or less consecutive to the total combustion, depending upon the degree of reduction of the catalyst, which is determined by the temperature and the gas phase composition. The calculation of the net rates of coke formation was included in the simulation. The influence of carbon dioxide and steam was also investigated.
TL;DR: The results of this study clearly show that the AFLP technique is a valuable new high-resolution genotypic tool for classification of Aeromonas species and also emphasize that this powerful DNA fingerprinting method is important for bacterial taxonomy in general.
Abstract: We investigated the ability of a recently developed genomic fingerprinting technique, named AFLP, to differentiate the 14 currently defined DNA hybridization groups (HGs) in the genus Aeromonas. We also determined the taxonomic positions of the phenospecies Aeromonas allosaccharophila, Aeromonas encheleia, Aeromonas enteropelogenes, and Aeromonas ichthiosmia, which have not been assigned to HGs yet. A total of 98 Aeromonas type and reference strains were included in this study. For the AFLP analysis, the total genomic DNA of each strain was digested with restriction endonucleases Apa I and Taq I. Subsequently, restriction fragments were selectively amplified under high-stringency PCR conditions. The amplification products were electrophoretically separated on a polyacrylamide gel and visualized by autoradiography. Following high-resolution densitometric scanning of the resulting band patterns, AFLP data were further processed for a computer-assisted comparison. A numerical analysis of the digitized fingerprints revealed 13 AFLP clusters which, in general, clearly supported the current Aeromonas taxonomy derived from DNA homology data. In addition, our results indicated that there is significant genotypic heterogeneity in Aeromonas eucrenophila (HG6), which may lead to a further subdivision of this species. A. allosaccharophila and A. encheleia did not represent a separate AFLP cluster but were found to be genotypically related to HG8/10 and HG6, respectively. In addition, the results of the AFLP analysis also confirmed the phylogenetic findings that A. enteropelogenes and A. ichthiosmia are in fact identical to Aeromonas trota (HG13) and Aeromonas veronii (HG8/10), respectively. The results of this study clearly show that the AFLP technique is a valuable new high-resolution genotypic tool for classification of Aeromonas species and also emphasize that this powerful DNA fingerprinting method is important for bacterial taxonomy in general.
TL;DR: In this paper, the RIASEC Model of vocational personalities and the Five-Factor Model of personality are used to assess individual differences among study majors and to predict educational achievement, and the results show that both models are useful to describe differences among different majors.
Abstract: In this study Holland's RIASEC Model of vocational personalities and the Five-Factor Model of personality are used (i) to assess individual differences among study majors and (ii) to predict educational achievement. A sample of 934 last-year students who enrolled in different academic majors filled out Dutch/Flemish adaptations of the NEO-PI-R (Costa and McCrae, 1992) and the Self-Directed Search (Holland, 1977; 1979). The results show that both models are useful to describe differences among different majors. Conscientiousness proves to be a general predictor of grades and study career. For the other Big Five dimensions, except for Agreeableness, major and/or gender specific relationships with educational outcomes are observed. Holland's interest dimensions are not related to educational achievement, except for some moderate gender or major specific correlations with the Investigative and the Artistic scales. Suggestions for future research regarding educational streaming and counselling are discussed.
TL;DR: The results do not support the model that catalase inactivation is the key route by which salicylic acid induces PR defense responses in healthy tissue, however, becauseCatalase deficiency is potentially lethal to leaves, catalases inactivation by salicyric acid could be of importance in the establishment of hypersensitive responses.
Abstract: Transgenic tobacco deficient in either Cat1 (Cat1AS), Cat2 (Cat2AS), or both (CatGH) was generated through sense and antisense technology. Cat1AS, Cat2AS, and CatGH plants showed no visible phenotype when grown at low light (100 µmol m−2 sec−1. Under these conditions, deficiency in Cat1 and/or Cat2 did not lead to constitutive pathogenesis-related (PR-1) expression and did not potentiate PR-1 induction by exogenous salicylic acid. This demonstrates that catalase suppression per se is not a sufficient signal for PR-1 induction. In Cat1-deficient plants exposed to higher light intensities (250–1000 µmol m−2 sec−1), PR-1 expression was induced without pathogenic challenge and multiplication of Pseudomonas syringae pv. syringae was repressed. Yet, it is unlikely that Cat1 deficiency is mimicking the mode of action of salicylic acid in tobacco, because, concurrent with PR-1 induction, Cat1 deficiency at high light provoked severe leaf damage, characterized by white necrotic lesions. Taken together, these results do not support the model that catalase inactivation is the key route by which salicylic acid induces PR defense responses in healthy tissue. However, because catalase deficiency is potentially lethal to leaves, catalase inactivation by salicylic acid could be of importance in the establishment of hypersensitive responses.
TL;DR: The release of three model proteins from hydrogels varying in water content and degree of GMA-substitution was studied and it was shown that the release of the proteins was independent of the degree ofGMA substitution of gels at high equilibrium water contents.
TL;DR: In this paper, it is demonstrated that impedance spectroscopy can be used for the energetic characterization of the semiconductor/electrolyte interface and how the mechanisms of electrochemical reactions are studied by the electrical impedance technique.
TL;DR: In this article, a simple measuring system was developed that yields information about the presence of NH + 4 and NO − 2 nitrogen in mixed liquor samples, which is valuable for detailed monitoring of the nitrification process in a reactor: it is simple, inexpensive, robust and generally applicable for nitrifying reactor systems.
TL;DR: The wavelength requirement for optical networks based on wavelength-division multiplexing (WDM) is discussed, and a new heuristic for routing and wavelength assignment is proposed and compared with the Dijkstra algorithm and with a solution based on integer linear programming.
Abstract: We discuss the wavelength requirement for optical networks based on wavelength-division multiplexing (WDM). A mathematical model, to represent the routing and wavelength assignment in optical networks with or without wavelength conversion, is described, and metrics are defined to express the performance. A new heuristic for routing and wavelength assignment is proposed and compared with the Dijkstra algorithm and with a solution based on integer linear programming. The different techniques are applied to a variety of network examples with different traffic loads.