Showing papers by "Katholieke Universiteit Leuven published in 1989"
TL;DR: In this paper, the authors sampled the soil horizons of 40 important Belgian soil series, with textures ranging from sand to heavy clay, and measured their moisture retention characteristic (MRC).
Abstract: We sampled the soil horizons of 40 important Belgian soil series, with textures ranging from sand to heavy clay, and measured their moisture retention characteristic (MRC). Of these horizons, the particle-size distribution in nine fractions, the dry bulk density, and the carbon content were determin
709 citations
TL;DR: In this article, a charge pumping technique is used to determine the degradation mechanisms in MOS transistors under all kinds of aging conditions (e.g., irradiation, hot-carrier, Fowler-Nordheim stress) and to quantify the degradation.
Abstract: It is shown that the charge pumping technique is able not only to determine the degradation mechanisms in MOS transistors under all kinds of aging conditions (eg, irradiation, hot-carrier, Fowler-Nordheim stress), but also in several cases to evaluate and to quantify the degradation It is further shown that the technique can be applied to separate the presence of fixed oxide changes due to charge trapping and the generation of interface traps It can be used to analyze degradations that occur uniformly over the transistor channel, as well as strongly localized transistor degradations (eg, for the case of hot-carrier degradations) All possible cases of uniform and nonuniform degradations, for p-channel as well as for n-channel transistors, are described, and for most of them experimental examples are given >
423 citations
TL;DR: This matrix algorithm for the identification of statespace models for multivariable linear time-invariant systems using (possibly noisy) input-output (I/O) measurements only draws its excellent performance from repeated use of the numerically stable and accurate singular value decomposition.
Abstract: A geometrically inspired matrix algorithm is derived for the identification of statespace models for multivariable linear time-invariant systems using (possibly noisy) input-output (I/O) measurements only. As opposed to other (mostly stochastic) identification schemes, no variance-covariance information whatever is involved, and only a limited number of I/O-data are required for the determination of the system matrices. Hence, the algorithm can be best described and understood in the matrix formalism, and consists of the following two steps. First, a state vector sequence is realized as the intersection of the row spaces of two block Hankel matrices, constructed with I/O-data. Then the system matrices are obtained at once from the least-squares solution of a set of linear equations. When dealing with noisy data, this algorithm draws its excellent performance from repeated use of the numerically stable and accurate singular value decomposition. Also, the algorithm is easily applied to slowly time-...
403 citations
TL;DR: It is concluded that EMA is a motilin receptor agonist because it had no effect on muscle strips of rat or dog duodenum but did induce contractions in human strips and was totally ineffective on ileal preparations, which are also unresponsive to motil in and in which motilIn binding is absent.
Abstract: Erythromycin A (EMA) is a potent stimulator of gastrointestinal motor activity. In vitro studies suggest that it mimics motilin, a peptide that stimulates motor activity in human and in rabbit via smooth muscle receptors. We have compared the in vitro contractile effect of EMA and two derivatives, 8,9-anhydro-EMA-6,9-hemiketal (EM201) and EMA N-oxide, on rabbit duodenal smooth-muscle strips with their ability to displace iodinated motilin bound to crude smooth-muscle membrane fractions. The concentrations required to induce 50% of the maximum contractile response to a supramaximal dose of acetylcholine were 5.0 x 10(-8), 2.0 x 10(-6), and 1.0 x 10(-4) M for, respectively, EM201, EMA, and EMA N-oxide. The concentrations required to displace 50% of the labeled motilin were, in the same order, 1.0 x 10(-8), 1.3 x 10(-7), and 4.0 x 10(-6) M. Both parameters were well correlated. The dose-response curve of the EMA was parallel to that of motilin and the effects of motilin and EMA were additive. Contractions induced by EMA were insensitive to pretreatment with tetrodotoxin or atropine. EMA had no effect on muscle strips of rat or dog duodenum but did induce contractions in human strips. EMA was totally ineffective on ileal preparations, which are also unresponsive to motilin and in which motilin binding is absent. EMA has therefore the same regional and species specificity as motilin. We conclude that EMA is a motilin receptor agonist.
316 citations
TL;DR: It is concluded that positive patchtests to corticosteroids occur approximately six to seven times more frequently in well‐defined groups of structurally‐related substances than between cortic Fosteroids of different groups.
Abstract: Contact allergy to topical corticosteroids occurs more frequently than previously supposed. Cross-allergic phenomena are common. On the basis of a review of the literature and our own patch test data on 15 patients, we conclude that positive patchtests to corticosteroids occur approximately six to seven times more frequently in well-defined groups of structurally-related substances than between corticosteroids of different groups. An analogous substitution pattern on the steroid D-ring or the carbon side chain (C20, C21) seems to have a significant influence on the association of positive patchtest results. This is not the case for other structural variables, such as the presence of a double bond in the steroid A-ring or fluoride substitutions on the B-ring. The effect of other factors such as concomitant sensitization and steroid metabolism in the skin on the development of a corticosteroid polyallergy are analysed, and the specificity and sensitivity of cross-allergy phenomena are evaluated. These are important in the selection of a topical steroid in the future treatment of a corticosteroid sensitive patient.
295 citations
TL;DR: The nettle lectin may be a promising candidate for possible applications in the genetic engineering of disease-resistant crops and synergistically with chitinase in inhibiting fungal growth.
Abstract: Rhizomes of stinging nettle contain a small-sized lectin that exhibits binding specificity toward chitin. This lectin inhibits growth of several phytopathogenic and saprophytic chitin-containing fungi in vitro. The antifungal action of the nettle lectin differs from the action of chitinases, which are a ubiquitous class of antifungal plant proteins. Moreover, the nettle lectin acts synergistically with chitinase in inhibiting fungal growth. The nettle lectin may be a promising candidate for possible applications in the genetic engineering of disease-resistant crops.
289 citations
TL;DR: Reaggregate cell cultures of mouse or rat anterior pituitary were found to produce interleukin-6 (IL-6), a cytokine known for its multiple actions in the immune system, and the presence of folliculo-stellate (FS) cells was revealed to be essential for IL-6 production.
Abstract: Reaggregate cell cultures of mouse or rat anterior pituitary were found to produce interleukin-6 (IL-6), a cytokine known for its multiple actions in the immune system. Studies on aggregates prepared from differentially enriched pituitary cell populations revealed the presence of folliculo-stellate (FS) cells to be essential for IL-6 production. Aggregates that contained only hormone-secreting, but no FS cells, failed to produce IL-6. Furthermore, the yield of IL-6 increased with increasing proportions of FS cells present in the aggregates. It is suggested that IL-6 participates in the local regulation of the secretory function of the hypophysis and may constitute a link between events in the immune system and those in the endocrine system.
275 citations
TL;DR: An exponential regression of the results measured for each property as a function of the volumetric filler fraction was appraised and an excellent correlation was found with each property.
274 citations
01 Sep 1989
TL;DR: Practical examples show that OPTIMAN quickly designs analog circuits, closely meeting the specifications, and that it is a flexible and reliable design and exploration tool.
Abstract: A methodology for the automatic design optimization of analog integrated circuits is presented. A non-fixed-topology approach is realized by combining the optimization program OPTIMAN with the symbolic simulator ISAAC. After selecting a circuit topology, the user invokes ISAAC to model the circuit. ISAAC generates both exact and simplified analytic expressions, describing the circuit's behavior. The model is then passed to the design optimization program OPTIMAN. This program is based on a generalized formulation of the analog design problem. For the selected topology, the independent design variables are automatically extracted and OPTIMAN sizes all elements to satisfy the performance constraints, thereby optimizing a user-defined design objective. The global optimization method used on the analytic circuit models is simulated annealing. Practical examples show that OPTIMAN quickly designs analog circuits, closely meeting the specifications, and that it is a flexible and reliable design and exploration tool. >
254 citations
TL;DR: Recordings from 183 single units of area V1 of monkeys performing an orientation discrimination task found to increase with increasing response strength, and the relationship between response variance and response strength was well described.
Abstract: In order to relate single cell performance to behavioral discrimination one needs measurements of the response variance of the units. We recorded from 183 single units of area V1 of monkeys performing an orientation discrimination task. The response variance was found to increase with increasing response strength. This relationship between response variance and response strength was well described by a power function with a power close to one. The response variance was on average 1.9 times the response strength. Despite important differences in preparation, the behaving monkey data are in good agreement with those previously obtained in paralysed and anesthetised animals.
252 citations
TL;DR: In patients taking active treatment total mortality was increased in the lowest thirds of treated systolic and diastolic blood pressures, suggesting some deterioration of general health.
Abstract: OBJECTIVE--To investigate the relation between mortality and treated systolic and diastolic blood pressures. DESIGN--Randomised double blind placebo controlled trial. Mortality in the two treatment groups was examined in thirds of treated systolic and diastolic blood pressures. PATIENTS--339 And 352 patients allocated to placebo and active treatment, respectively. The groups were similar at randomisation in sex ratio (70% women), mean age (71.5 years), blood pressure (182/101 mm Hg), and proportion of patients with cardiovascular complications (35%). MEASUREMENTS AND MAIN RESULTS--In the placebo group total mortality rose with increasing systolic pressure whereas it had a U shaped relation with diastolic pressure, the total lowest mortality being in patients in the middle third of the distribution of diastolic pressure. In the group given active treatment total mortality showed a U shaped relation with systolic pressure and an inverse association with treated diastolic pressure. In both groups cardiovascular and non-cardiovascular mortality followed the same trends as total mortality. The increased mortality in the lowest thirds of pressure was not associated with an increased proportion of patients with cardiovascular complications at randomisation or with a fall in diastolic pressure exceeding the median fall in pressure in each group. In contrast, patients in the lowest thirds of pressure showed greater decreases in body weight and haemoglobin concentration than those in the middle and upper thirds of pressure. CONCLUSIONS--In patients taking active treatment total mortality was increased in the lowest thirds of treated systolic and diastolic blood pressures. This increased mortality is not necessarily explained by an exaggerated reduction in pressure induced by drugs as for diastolic pressure a U shaped relation also existed during treatment with placebo. In addition, patients in the lowest thirds of systolic and diastolic pressures were characterised by decreases in body weight and haemoglobin concentration, and the patients in the lowest thirds of diastolic pressure taking active treatment also by an increased non-cardiovascular mortality, suggesting some deterioration of general health.
TL;DR: Extensive overlap of latencies in all 3 regions at both the high and low ends of their respective ranges indicates a considerable degree of parallel interaction between striate and extrastriate cortex.
TL;DR: A synthetic "mixed" triglyceride (1,3-distearoyl,2[13C]octanoyl glycerol), having a medium-chain fatty acid in the 2 position, was evaluated as a substrate for an exocrine pancreatic function test by comparing the 13CO2 breath excretion with the lipase output in the duodenum.
TL;DR: While tumor stage had only a limited impact in the range of tumors included in this study, the localisation of the tumor significantly influenced cosmetic outcome with worse results for inferior and medial localisations.
TL;DR: In this article, the TLS problem is generalized in order to maintain consistency of the parameter estimates in a general errors-in-variables model; i.e., some of the columns of A may be known exactly and the covariance matrix of the errors in the rows of the remaining data matrix may be...
Abstract: The Total Least Squares (TLS) method has been devised as a more global fitting technique than the ordinary least squares technique for solving overdetermined sets of linear equations $AX \approx B$ when errors occur in all data. This method, introduced into numerical analysis by Golub and Van Loan, is strongly based on the Singular Value Decomposition (SVD). If the errors in the measurements A and B are uncorrelated with zero mean and equal variance, TLS is able to compute a strongly consistent estimate of the true solution of the corresponding unperturbed set $A_0 X = B_0 $. In the statistical literature, these coefficients are called the parameters of a classical errors-in-variables model.In this paper, the TLS problem, as well as the TLS computations, are generalized in order to maintain consistency of the parameter estimates in a general errors-in-variables model; i.e., some of the columns of A may be known exactly and the covariance matrix of the errors in the rows of the remaining data matrix may be...
TL;DR: In this paper, the specific effect of the stabilizer layer is investigated using suspensions of monodisperse PMMA particles with a chemically attached stabilizer, and the ratio between particle radius and stabilizer thickness is changed between 5 and 61.
Abstract: The non-Newtonian viscosities of polymerically stabilized colloidal suspensions are usually predicted and correlated on the basis of data and scaling principles for Brownian hard spheres. Here, the specific effect of the stabilizer layer is investigated using suspensions of monodisperse PMMA particles with a chemically attached stabilizer layer. The ratio between particle radius and stabilizer layer thickness is changed between 5 and 61. At high values of this ratio the data show Brownian hard sphere behavior. At lower values deviations appear. As a first approximation, the “softness” of the particles can be characterized through the concentration at maximum packing. A more detailed comparison with hard sphere data provides a measure for softness that changes with concentration and shear rate. A theoretical estimate of the concentration effect is in line with the experiments. The critical shear stress (or Peclet number) is not a constant but goes through a maximum when the concentration is increased.
TL;DR: Patients with haematological malignancies were treated prophylactically with itraconazole during remission induction therapy with the aim of preventing recurrence of disease.
Abstract: Seventy-two patients with haematological malignancies were treated prophylactically with itraconazole during remission induction therapy. The incidence of proven fungal infections was 18%, of which 12.5% were fatal. Aspergillus, Torulopsis and Candida proved to be major invasive pathogens. Plasma levels of itraconazole were monitored for all patients. The occurrence of fungal infection is significantly greater in the group where no therapeutic plasma levels were obtained during at least two weeks. There is a clear need to obtain quick information on itraconazole plasma levels in order to adapt dosage during prophylactic treatment in immunocompromised patients. The influence of itraconazole on liver function tests could not be separated from concomitant cytostatic or antibiotic treatment. No jaundice directly related to itraconazole could be found. During itraconazole prophylaxis a shift from classic pathogens such as Aspergillus and Candida, to Fusarium, Torulopsis and Mucor, may be seen.
TL;DR: The specific reactivity of the polyclonal antiserum confirms the identity of the 48K5 clone and distinguishes the 48- and the 90-kDa core proteins, which do share the 6G12-defined epitope and at least one additional antigenic determinant with the48K5 cDNA-encoded protein, from the 125-, 64-, and 35-k da core proteins of cell surface HSPG of human lung fibroblasts which do not react with either
08 May 1989
TL;DR: In this article, a generalized version of the linear complementarity problem is used to analyze a broad class of piecewise-linear circuits, where nonlinear resistors that are neither voltage nor current controlled can be allowed and no restrictions on the linear part of the circuit have to be made.
Abstract: An important application of complementarity theory consists in solving sets of piecewise-linear equations and hence in the analysis of piecewise-linear resistive circuits. The authors show how a generalized version of the linear complementarity problem can be used to analyze a broad class of piecewise-linear circuits. Nonlinear resistors that are neither voltage nor current controlled can be allowed, and no restrictions on the linear part of the circuit have to be made. As a second contribution, the authors describe an algorithm for the solution of the generalized complementarity problem and show how it can be applied to yield a complete description of the DC solution set as well as of driving-point and transfer characteristics. >
TL;DR: In this paper, the role of the casein micelle surface, as affected by adsorption of heat-denatured whey proteins, on yogurt texture was investigated by electron microscopy, showing that filaments of denatured β-lactoglobulin developed on the micellar surface and offered a barrier to micelle fusion.
TL;DR: The characteristics of the voltage multiplier circuit are thoroughly analyzed and modeled and its capability to compensate for nonvolatile memory degradation is shown.
Abstract: Most of the presently available EEPROM circuits feature 5-V-only operation and therefore incorporate on-chip high-voltage generators. In spite of the importance of these latter circuits, a thorough analysis of the circuit has not been presented. In this paper the characteristics of the voltage multiplier circuit are thoroughly analyzed and modeled. The results obtained from this analysis are fully confirmed by experiments. The degradation characteristics of the circuit are discussed and its capability to compensate for nonvolatile memory degradation is shown. >
TL;DR: Comparison of the dose‐response curves of OA on maturation, isolated enzymes and phosphatase activities in crude oocyte preparations suggests that inhibition of both polycation‐stimulated (PCS) and ATP,Mg‐dependent (AMD) phosphatases is sufficient but requires that a critical phosphorylation level is attained of one or several of their substrates, resulting in the formation of active MPF and meiotic maturation.
TL;DR: In this paper, the authors evaluated the effect of recombinant tissue-type plasminogen activator (rt-PA) on the recanalisation of occluded coronary arteries.
Abstract: Coronary arterial thrombolysis is becoming an established treatment of acute myocardial infarction. If given early enough, it recanalises occluded coronary arteries, salvages myocardial function and reduces mortality. A reduction of mortality in patients with acute myocardial infarction has now been demonstrated for streptokinase, anisoylated plasminogen streptokinase activator complex (APSAC; anistreplase) and recombinant tissue-type plasminogen activator (rt-PA). From the biochemical point of view, rt-PA has several attractive properties. It is similar to or identical with the physiological plasminogen activator in blood, it does not induce an antibody response, and it is more fibrin-specific than most or all other currently known thrombolytic agents. The rate of recanalisation of occluded coronary arteries with rt-PA is about 60 to 80% in non-comparative and placebo-controlled trials. rt-PA was similar in efficacy to urokinase in the only trial to compare the 2 agents. In 2 comparative trials evaluated by meta-analysis, rt-PA appeared more effective than streptokinase for the early recanalisation of occluded arteries. Both agents were comparable in their effects on left ventricular function in 2 comparative trials, but further study is needed to conclusively evaluate this parameter. Moreover, both agents reduce inhospital mortality, but much larger direct comparative trials are required before scientifically valid statements can be made on the relative clinical efficacy of available thrombolytic agents in terms of their effects on both morbidity and mortality. Thus, rt-PA constitutes a notable contribution of recombinant DNA technology to the treatment of thromboembolic disease, the main cause of death and disability in Western societies.
TL;DR: A logistic regression model was used to develop a numerical scoring system for personal loans as discussed by the authors, which is used to evaluate the creditworthiness of a loan applicant's creditworthiness. But this model is not suitable for credit-card applications.
Abstract: A logistic regression model is used to develop a numerical scoring system for personal loans.
TL;DR: Les statistiques de survie a court et long terme et de fonction ventriculaire gauche apres traitement par thrombolyse de l'infarctus aigu montrent que les effets benefiques de the reperfusion coronarienne ne dependent pas seulement de the recuperation du myocarde ischemique.
TL;DR: In this paper, a ten-membered ring zeolite was synthesized in the presence of diaminohexane, which acts as a pore filling agent during synthesis.
01 Jun 1989
TL;DR: An iterative loop-folding procedure, implemented in the CATHEDRAL II compiler, is presented, which may significantly improve the utilization of parallel hardware, available in a data path.
Abstract: In this paper, we discuss a control-flow transformation called loop folding, during the scheduling of register-transfer code for DSP-systems. Loop folding is functionally equivalent to data-path pipelining. An iterative loop-folding procedure, implemented in the CATHEDRAL II compiler, is presented. This technique may significantly improve the utilization of parallel hardware, available in a data path.
TL;DR: Warning is given against the use of polytetrafluoroethylene paste in children or young adults with a normal life expectancy after periurethral injection of Teflon paste.
TL;DR: This tumor cell growth inhibitory effect was completely suppressed by the addition of catalase to the culture medium containing vitamins C and K3, suggesting an excessive production of hydrogen peroxide as being implied in mechanisms responsible for the above‐mentioned effects.
Abstract: The effects of sodium ascorbate (vitamin C) and 2-methyl-1,4-naphthoquinone (vitamin K3) administered separately or in combination on the in vitro cultured human neoplastic cell lines MCF-7 (breast carcinoma), KB (oral epidermoid carcinoma), and AN3-CA (endometrial adenocarcinoma) have been examined. When given separately, vitamin C or K3 had a growth inhibiting action only at high concentrations (5.10(3) mumol/1 and 10(5) nmol/l, respectively). Combined administration of both vitamins demonstrated a synergistic inhibition of cell growth at 10 to 50 times lower concentrations. At this level separately given vitamins are not toxic. The sensitivity to this treatment was somewhat different in the three cell lines, being slightly higher for KB line. This tumor cell growth inhibitory effect was completely suppressed by the addition of catalase to the culture medium containing vitamins C and K3, suggesting an excessive production of hydrogen peroxide as being implied in mechanisms responsible for the above-mentioned effects.