Showing papers by "Katholieke Universiteit Leuven published in 1971"
TL;DR: In this article, the authors explore several variables that characterize organic organization to test whether they are associated with varying rates of innovation, such as the number of occupational specialities, the inten...
Abstract: This study explores several variables that characterize organic organization to test whether they are associated with varying rates of innovation. The number of occupational specialities, the inten...
607 citations
TL;DR: Positivity bias is approached from three viewpoints: (a) It may be the effect of purely cognitive dispositions. (b) As such, it may function as an hypothesis about reality; and (c) the subject may seek rewarding behavioral interactions with entities within his life space as discussed by the authors.
Abstract: Positivity bias is approached from three viewpoints: (a) It may be the effect of purely cognitive dispositions. (b) As such, it may function as an hypothesis about reality. The related dynamic factor would be a tendency toward cognitive validity which may lead to an orientation toward the negative as a means to test the positivity-hypothesis. (c) Finally, the subject may seek rewarding behavioral interactions with entities within his life space. In this context cognitive positivity bias may reflect a behavioural approach bias which can be related to the dynamics of ‘mere survival’ and ‘self-actualization’.
202 citations
01 Jan 1971
TL;DR: In this paper, the authors present a mathematical description of the feedback system, well-posedness, stability and stability in the time-invariant case, and stability and instability in the constant case.
Abstract: This chapter contains sections titled: 5.1 Mathematical Description of the Feedback System, 5.2 Well-Posedness, 5.3 Stability and Instability in the Time-Invariant Case, References
103 citations
TL;DR: In this article, an approximate formula for the inversion of the Laplace transform was derived from a gaussian integration formula for Bromwich's inversion integral, which is exact whenever F(p) is a linear combination of p−s+k,k=0, 1, 2,..., 2N−1, withs an arbitrary positive real number.
Abstract: An approximate formula for the inversion of the Laplace transformF(p) is studied. The formula is exact wheneverF(p) is a linear combination ofp−s+k,k=0, 1, 2, ..., 2N−1, withs an arbitrary positive real number. The formula is derived from a gaussian integration formula for Bromwich's inversion integral.
76 citations
TL;DR: It is concluded that the left apex cardiogram provides a reliable noninvasive technique for the timing of intracardiac events.
Abstract: The left apex cardiogram was recorded in the dog by means of a pulse transducer with an infinite time constant. The time relation between the left apex cardiogram and left ventricular and aortic pressure tracings (recorded by means of high fidelity micromanometers) and their first time derivatives (dp/dt) was studied. Both the onset of the upstroke and the protodiastolic nadir of the left apex cardiogram and of the left ventricular pressure curve were found to occur nearly simultaneously. This close relation was preserved during various acutely induced hemodynamic changes and during right and left ventricular pacing. The E point of the left apex cardiogram occurred simultaneously with the peak dp/dt of the left ventricular pressure, or followed it with a time lag of 2 to 35 msec. Diastolic waves also occurred simultaneously. It is concluded that the left apex cardiogram provides a reliable noninvasive technique for the timing of intracardiac events.
72 citations
TL;DR: The application of this method to the jejunal crypts of several animal species indicates that Paneth cell granules contain lysozyme, and the binding of the hydrolysis products with Alcian Blue is so strong that any other alcianophilia can be removed selectively.
Abstract: The breakdown products resulting from the hydrolysis of chitin by lysozyme stain with Alcian Blue. A method based upon this observation has been developed for the histochemical demonstration of lysozyme activity. The application of this method to the jejunal crypts of several animal species indicates that Paneth cell granules contain lysozyme. The binding of the hydrolysis products with Alcian Blue is so strong that any other alcianophilia (e.g. of acid mucosubstances in goblet cells) can be removed selectively by washing withN-cetylpyridinium chloride and counterstaining with Basic Fuchsin and Nuclear Fast Red.
69 citations
TL;DR: An infrared spectroscopic study has been made of the hydroxyl groups in so-called ultrastable faujasites and deep-bed calcined NH 4 Y samples.
68 citations
TL;DR: The dissociation of various tritium-labeled 17β-hydroxysteroids from the steroid binding β-globulin1 (SBβG) was studied by ammonium sulfate precipitation of the steroid-SB βG complex at different intervals after the addition of an excess of unlabeled testosterone or dihydrotestosterone.
Abstract: The dissociation of various tritium-labeled 17β-hydroxysteroids from the steroid binding β-globulin1 (SBβG) was studied by ammonium sulfate precipitation of the steroid-SBβG complex at different intervals after the addition of an excess of unlabeled testosterone or dihydrotestosterone.2 At 0 C the dissociation rate constant found for dihydrotestosterone was 0.009 min−1, 0.031 min−1 for 5α-androstane-3α,17β-diol, 0.054 min−1 for testosterone, 0.088 min−1 for androst-5-ene-3β,17β-diol and 0.21 min−1 for 17β-estradiol. At 37 C the dissociation of dihydrotestosterone and of testosterone was about 40 times faster than at 0 C. The between person variation of the dissociation rate constant of testosterone at 0 C [0.054±0.0028 (sd) min−1; N =13] and of dihydrotestosterone at 20 C [0.059±0.0029 (sd) min−1; N =12] was small. No significant differences in dissociation were found between plasma samples of men, plasma samples of normal, hirsute or pregnant women, and umbilical cord blood plasma.
62 citations
01 Oct 1971
TL;DR: In this article, the authors present two methods for numerical inversion of a Laplace transform, a very economical method, suitable only for a limited class of Laplace transforms, and a general method, which is compared with other general methods.
Abstract: The calculation of the transient response corresponding to a given frequency response is a problem of numerical inversion of a Laplace transform. Two methods are presented: a very economical method, which is suitable only for a limited class of Laplace transforms, and a general method. FORTRAN programs for both methods are described. The general method is compared with other general methods.
55 citations
TL;DR: Compared with the accepted conjugation with glucuronic acid as a major route of detoxification in mammals, the detection of large amounts of xylose and glucose conjugates of bilirubin in dog bile suggests that the underlying biosynthetic pathways may be important alternative routes of detoxication.
Abstract: 1. T.l.c. with neutral solvent systems of ethyl anthranilate azopigments derived from bile of man, dog and rat revealed pronounced species variation. The less polar components (alpha-group) could be separated conveniently by development with chloroform-methanol (17:3, v/v). 2. The azopigment material derived from gallbladder bile of dog contained about 10% of azobilirubin beta-d-monoxyloside (azopigment alpha(2)) and 30% of azobilirubin beta-d-monoglucoside (azopigment alpha(3)). The sugar moieties were identified by t.l.c. with acidic, neutral and basic solvent systems and by anion-exchange column chromatography of their boric acid complexes. Treatment of the purified azopigments with ammonia vapour led to the formation of the amide of azobilirubin, indicating that both pigments are ester glycosides. The beta-d configuration was demonstrated by enzymic studies with emulsin (an adequate source of beta-glucosidase activity) and with Mylase-P (an adequate source of beta-glucosidase and beta-xylosidase activities). 3. Hydrolysis studies with model substrates and with the alpha(2)- and alpha(3)-azopigments suggested that in Mylase-P the beta-glucosidase and beta-xylosidase activities reside in separate enzymes. 4. Compared with the accepted conjugation with glucuronic acid as a major route of detoxication in mammals, the detection of large amounts of xylose and glucose conjugates of bilirubin in dog bile suggests that the underlying biosynthetic pathways may be important alternative routes of detoxication.
55 citations
TL;DR: The conductance for Sr ions as a function of (Sr)e follows Michaëlis-Menten characteristics, suggesting that the Sr conductance is determined by a first order reaction between Sr and a site on the cell membrane.
Abstract: The characteristics of the regenerative increase in conductance for Sr ions in cardiac Purkyně fibres was examined as a function of (Sr)
e
, in the presence and absence of Ca ions. The maximum rate of depolarization during the upstroke of the action potential was not linearly related to log (Sr)
e
but tended to become constant at high external Sr concentrations, and was also inhibited by increasing Ca concentrations. The conductance for Sr ions as a function of (Sr)
e
follows Michaelis-Menten characteristics, suggesting that the Sr conductance is determined by a first order reaction between Sr and a site on the cell membrane. The behaviour in the presence of Ca can be explained by Ca acting as a competitive inhibitor.
TL;DR: In this paper, a new method for the calculation of the integrals is presented, where the function f(x) is approximated by a sum of Chebyshev polynomials, which are then used to calculate a Neumann series approximation forI1(m) and I2(m).
Abstract: A new method for the calculation of the integrals
$$I_1 (m) = \int\limits_a^b {f(x)\sin mxdx} andI_2 (m) = \int\limits_a^b {f(x)\cos mxdx}$$
is presented. The functionf(x) is approximated by a sum of Chebyshev polynomials. The Chebyshev coefficients are then used to calculate a Neumann series approximation forI1(m) andI2(m).
TL;DR: The binding of 17β-hydroxy-5α-androstan-3-one (dihydrotestosterone, DHT) to the steroid-binding β-globulin (SBβG) in human plasma was evaluated by means of three parameters, based on ammonium sulphate precipitation of this globulin.
TL;DR: The islets of Langerhans of the neonatal pancreas are a heterogeneous group and the composition appears to vary according to the staining method used, while in babies from mothers with reduced carbohydrate tolerance the islets contain an increased proportion of B cells and Ag+ cells.
Abstract: The islets of Langerhans of the neonatal pancreas are composed of B cells and non-B cells. The non-B cells are a heterogeneous group and the composition appears to vary according to the staining method used. Silver impregnation methods sometimes impregnate a small number of B cells. No complete identity exists between argyrophilic cells (Hellerstrom-Hellman modifications of the Davenport technique) and D cells. In babies from mothers with reduced carbohydrate tolerance the islets contain an increased proportion of B cells and Ag+ cells. Such an increase is not found in babies with erythroblastosis or alpha-thalassaemia. An active hypothalamohypophyseal system seems to be obligatory for complete maturation of the foetal islet tissue. In babies of diabetic mothers hyperplasia of the B cell appears only when a complete hypothalamo-hypophyseal system is present.
TL;DR: The clinical, hemodynamic, and angiocardiographic features of this rare type of cyanotic heart disease are described in two children and reviewed in 13 previously reported cases.
Abstract: Hypoplasia of the right ventricle, unassociated with severe pulmonary or tricuspid valvar malformations, is a primary congenital abnormality in which the trabeculated sinus portion of the ventricle fails to develop. An atrial septal defect or a stretched foramen ovale serves as an escape valve. The clinical, hemodynamic, and angiocardiographic features of this rare type of cyanotic heart disease are described in two children and reviewed in 13 previously reported cases. The clinical spectrum varies considerably in accordance with the degree of hypoplasia. Severe forms of hypoplasia, usually presenting in infancy, closely resemble tricuspid or pulmonary atresia. The electrocardiogram in hypoplasia, which shows right atrial enlargement and absence of right ventricular electrical forces, may be indistinguishable from an electrocardiogram in atresia. Lesser degrees of hypoplasia should be differentiated from Ebstein's malformation and anomalies of the systemic venous return. Both our patients, who had only mi...
TL;DR: In this paper, a necessary and sufficient condition for unitary equivalence of pure quasifree states over the Weyl algebra is proved, and partial results on states over this algebra are formulated in Theorem 1, and Lemmas 1, 4, 5 and 6.
Abstract: A necessary and sufficient condition for unitary equivalence of pure quasifree states over the Weyl algebra is proved. Some partial results on states over the Weyl algebra are formulated in Theorem 1, and Lemmas 1, 4, 5 and 6.
Journal Article•
TL;DR: The structures of the alpha(2)- and alpha(3)-azopigments, prepared by diazotization of dog bile with ethyl anthranilate, were shown by mass spectrometry and g.r.l.c. to correspond to azobilirubin beta-d-xylopyranoside and azobilIRubinbeta- d-glucopyranuside respectively.
Abstract: 1. The structures of the α2- and α3-azopigments, prepared by diazotization of dog bile with ethyl anthranilate, were shown by mass spectrometry and g.l.c. to correspond to azobilirubin β-d-xylopyranoside and azobilirubin β-d-glucopyranoside respectively. 2. Both azopigments consist of a mixture of two methyl vinyl isomers having structures (IIIa) and (IIIb) for the α2-azopigment and structures (IVa) and (IVb) for the α3-azopigment. Separation of methyl vinyl isomers was obtained by t.l.c. or column chromatography performed on the acetylated azopigments. Hydrolysis of the less polar acetates derived from components (IIIa) and (IVa) gave rise to the azopigment (Ia), whereas hydrolysis of the more polar acetates derived from components (IIIb) and (IVb) gave rise to the azopigment acid (Ib). The positions of methyl and vinyl substituents in compounds (Ia) and (Ib) were assigned on the basis of their n.m.r. spectra. 3. Molecular ions in the mass spectra of the trimethylsilyl and acetyl derivatives of the azopigments indicated the presence of a pentose and a hexose conjugating sugar. 4. The ester functions linking the sugars to the propionic acid side chain of azobilirubin were demonstrated by ammonolysis and identification of the amide of azobilirubin as the aglycone derivative. 5. The sugar moieties were shown to occur as xylopyranose (α2) and glucopyranose (α3), bound at C-1, by application of a sequence of reactions performed on a micro-scale. The sugar hydroxyl groups were acetylated and the 1-acyl aglycone removed selectively by treatment with hydrogen bromide in acetic acid. Hydrolysis of the 1-bromo sugar acetates followed by acetylation afforded the α- and β-xylopyranose tetra-acetates and α- and β-glucopyranose penta-acetates, identified by a combination of g.l.c. and mass spectrometry. 6. The validity of this degradation scheme was confirmed (a) by g.l.c.–mass spectrometry identification of the α- and β-1-propionyl derivatives of glucopyranose tetra-acetate, obtained from the α3-azopigment after final reaction with propionic anhydride; (b) by subjecting the acetates of αβ-glucopyranose, αβ-xylofuranose and αβ-glucofuranose to the same sequence of reactions.
TL;DR: A significant correlation between cortical and trabecular bone mass was established in women and a signifikante Korrelation zwischen corticaler andtrabeculärer Knochenmasse festgestellt was found.
Abstract: Trabecular bone mass was measured in the iliac crest of 129 cadavera of both sexes with a physical method based on the principle of Archimedes. Cortical bone mass was measured at the second metacarpal of the right hand with a graphimetric X-ray method in 77 cases. Trabecular and cortical bone mass decreased significantly with age in women but not in men. A significant correlation between cortical and trabecular bone mass was established in women.
TL;DR: Horseradish peroxidase has been used as a cytochemical tracer to study peculiar ultra-structural aspects of exogenous protein uptake and fate in four types of rat liver cells to describe the localization of HRP in cytoplasmic annular profiles and intercellular spaces.
TL;DR: Nuclear 5α-reduction of testosterone is thus not limited to accessory sex organs or to male animals, and 17β-hydroxy-5α-androstan-3-one (dihydrotestosterone) is formed by this nuclear fraction in both sexes.
Abstract: The in vitro metabolism of testosterone has been studied in a purified nuclear fraction of kidneys obtained from male and female rats. In the presence of an NADPH-generating system, 17β-hydroxy-5α-androstan-3-one (dihydrotestosterone) is formed by this nuclear fraction in both sexes. Nuclear 5α-reduction of testosterone is thus not limited to accessory sex organs or to male animals. Reduction of dihydrotestosterone to 5α-androstane-3α, 17β-diol, on the contrary, amounts to about 20% of the total Δ4-5α-reduced metabolites in nuclei from male animals, while it is almost absent in nuclei from female rats. (Endocrinology 89: 842,1971)
TL;DR: In this article, the adiabatic compressibility β s, the specific heat C p and C υ and their ratio γ have been derived for gaseous argon between 100 and 170 K up to pressures of 65 atm.
TL;DR: The functional significance of cells with the ultrastructural characteristics of neurosecretory cells in the lung lobules of prematurely born human infants includes the possibility that they modulate lobular secretion during foetal life, which would thus regulate lobular growth according to Towers's theory.
Abstract: IN this report, we describe cells with the ultrastructural characteristics of neurosecretory cells in the lung lobules of prematurely born human infants. The existence of these cells in the lungs of newborn infants was first suggested by Lauweryns and Peuskens on the basis of light and fluorescence microscopy1. Previously, analogous cells had been found in the lungs of infants2 and in adult lung3 with the light and electron microscopes4,5. There is no certainty that all authors are reporting the same cells, even within their own material; for example, Feyrter proposes a change in their argyrophilic properties during the first few years of life6. The functional significance of these cells in premature infants includes the possibility that they modulate lobular secretion during foetal life, which would thus regulate lobular growth according to Towers's theory7; and also that they may be one of the still unknown factors which modulates normal perinatal cardiopulmonary adaptation8 and which plays a role in respiratory distress syndrome, a condition with clinical9 and anatomical10 characteristics of hypoperfusion.
TL;DR: In this paper, a scanning electron microscope was used to study the morphology of vapour grown magnesium by-product during the Bridgman growth of magnesium, and the morphology varied in the same colony from polyhedra and composite prisms with rings on the (0001) and parabolae on the 10 1 0) planes over spheres with or without crystallographic planes.
TL;DR: In this article, a Ge(Li) and NaI (Tl) detector combination was used for the analysis of the γ-decay of 125Te and the results for the character of the observed transitions are: two pure M1 transitions (172 and 209 keV), two pure E1 transitions, one pure E2 transition (379 keV) and finally one mixed transition (204 keV); the experimental results are compared with the predictions of the Kisslinger-Sorensen calculations and a striking agreement is found.
TL;DR: By multiple regression analysis 3 percent of the individual variations in circulation time could be explained and large individual variations and sex differences have to be borne in mind in using the arm to tongue circulation time as a diagnostic test.
Abstract: The arm to tongue circulation time was determined with magnesium sulfate in an epidemiologic examination of 202 men and 305 women over 60 years of age (mean age 70.6 years). There was a significant difference between the average circulation time of men (16.5 ± 4.0 seconds) and women (13.3 ± 2.9 seconds). An increase of the mean circulation time of 1 second per decade of age was demonstrated. The normal lower limit for aged people is 10 seconds for men and 8 seconds for women, and the upper limit is 21 seconds for men and 19 seconds for women. Several factors, both cardiac and extrinsic, determine the circulation time. There was a significant correlation between the circulation time and various indexes, among which the diameter of the heart (r = +0.36), heart rate (r = −0.37) and body height (r = +0.37) seemed to be the most important. By multiple regression analysis 3 percent of the individual variations in circulation time could be explained. These large individual variations and sex differences have to be borne in mind in using the arm to tongue circulation time as a diagnostic test.