Showing papers by "Katholieke Universiteit Leuven published in 1980"
1,099 citations
TL;DR: Trophoblastic invasion of the human decidua has been studied in 48 intact uteri with pregnancies ranging from 8 to 18 weeks after the last menstrual period to find out the role played by these cells in placentation.
792 citations
744 citations
TL;DR: Closely spaced samples from an uninterrupted calcareous pelagic sequence across the Cretaceous-Tertiary boundary reveal that the extinction of planktonic Foraminifera and nannofossils was abrupt without any previous warning in the sedimentary record, and that the moment of extinction was coupled with anomalous trace element enrichments, especially of iridium and osmium.
Abstract: Closely spaced samples from an uninterrupted calcareous pelagic sequence across the Cretaceous–Tertiary boundary reveal that the extinction of planktonic Foraminifera and nannofossils was abrupt without any previous warning in the sedimentary record, and that the moment of extinction was coupled with anomalous trace element enrichments, especially of iridium and osmium. The rarity of these two elements in the crust of the Earth indicates that an extraterrestrial source, such as the impact of a large meteorite may have provided the required amounts of iridium and osmium.
361 citations
TL;DR: Microscopical examination reveals that the apparent stimulation of bone ingrowth into the surface pores of the implant is the reason for the increased rate of bond formation, and weight bearing might be allowed much earlier, thus reducing the recuperation period.
Abstract: Skeletal fixation of permanent implants by new methods such as fixation by mechanical interlocking of bone with porous prosthetic coatings or chemical bonding with bioactive materials shows growing potential. This paper reports on the resulting skeletal fixation of a combined porous and bioactive material. Metal plugs with a porous metal fiber coating impregnated with hydroxyapatite were implanted for 2, 4, and 12 weeks and were compared to the parent porous, nonbioactive, metal fiber material. Statistical analysis of the interfacial failure shear stress, as obtained by mechanical testing, shows there is a marked influence of hydroxyapatite impregnation on the rate of bone ingrowth and the strength of the interfacial bond the few weeks following surgery. Microscopical examination reveals that the apparent stimulation of bone ingrowth into the surface pores of the implant is the reason for the increased rate of bond formation. The results are of particular clinical interest: with an increased rate of bone ingrowth, weight bearing might be allowed much earlier, thus reducing the recuperation period.
316 citations
305 citations
TL;DR: For a distribution function F on [0, ∞] we say F ∈ if for some fixed γ > 0, and for each real, limx→∞ {1-F(x + y)/{1- F(x)} ═ e − n. The related classes ℒt are proved closed under convolutions, which implies the closure of the class of positive random variables with regularly varying tails under multiplication as mentioned in this paper.
Abstract: For a distribution function F on [0, ∞] we say F ∈ if {1 – F(2)(x)}/{1 – F(x)}→2 as x→∞, and F∈, if for some fixed γ > 0, and for each real , limx→∞ {1 – F(x + y)}/{1 – F(x)} ═ e– n. Sufficient conditions are given for the statement F ∈ F * G ∈ and when both F and G are in y it is proved that F*G∈pF + 1(1 – p) G ∈ for some (all) p ∈(0,1). The related classes ℒt are proved closed under convolutions, which implies the closure of the class of positive random variables with regularly varying tails under multiplication (of random variables). An example is given that shows to be a proper subclass of ℒ 0.
281 citations
TL;DR: Investigation of identical twin-sisters presented at 2 years of age with marked psychomotor retardation and bone-age of 1 year revealed markedly fluctuating basal serum prolactin, FSH, GH and GH, but otherwise normal thyroid function including TRH test, arylsulphatase A and lymphocyte karyotype.
Abstract: Identical twin-sisters (born at 36 wks; birthweight 2.2 and 3.0 kg) presented at 2 years of age with marked psychomotor retardation and bone-age of 1 year. Physical growth and phenotype were normal. Repeated investigations revealed: markedly fluctuating basal serum prolactin (778-5652 μU/ml; nl < 800), FSH (17-55 mIU/ml; nl < 10) and GH (2-144 ng/ml; nl < 10), but normal LH; low TBG (1.1 and 1.2 mg/dl; nl 1.6-2.4) also present in the father, with otherwise normal thyroid function including TRH test, arylsulphatase A moderately increased in serum (mean 293 and 272 nmol/ml; nl 30-130) but not in leukocytes, without increase of other lysosomal enzymes, and increasing CSF protein. Normal results were found for GH response to i.m. glucagon, urinary excretion of 17-keto and 17-hydroxysteroids, at funduscopy and for lymphocyte karyotype (Giemsa banding), buffy coat of blood leukocytes and electronmicroscopy of conjunctiva. Sella tursica was normal on x-ray. Cortical and cerebellar hypotrophy was evident on CAT-scan. Electromyography was normal but nerve conduction velocity was delayed (30-31 m/sec; nl 50 ± 1). A nerve and muscle biopsy is planned. At this stage we have no satisfactory explanation for these unusual findings.
246 citations
TL;DR: Close similarities in immunological properties and molecular weights support the hypothesis that plasminogen activator is synthesized in the vascular wall and released into the circulating blood.
246 citations
TL;DR: In this paper, the transformations of the Weyl and vector multiplet are purely superconformal covariantizations of the linearized rules, and the decomposition of Poincare supersymmetry in terms of super-formal transformation is exhibited for all submultiplets.
229 citations
TL;DR: A pseudo-polynomial algorithm is given to enumerate all these efficient points to minimize the holding cost and the maximum tardiness of n jobs to be sequenced on a single machine.
TL;DR: In this paper, motilin and gastrin levels were analyzed in relation to the interdigestive motor complex in humans, taking the onset of a duodenal activity front (phase 3 of the complex) as a reference point and the time lapse between two fronts as a time base.
TL;DR: It is postulate that the primary amines, methylamine and mono-dansylcadaverine, interfere with the recycling of α 2 M receptors, while the chemical nature of the amines and the conditions under which inhibition becomes apparent point to the involvement of transglutaminase in this recycling.
TL;DR: The primary method of therapy used by almost all physicians for the management of acute deep-vein thrombosis and pulmonary embolism has been anticoagulation.
Abstract: Excerpt For over three decades, the primary method of therapy used by almost all physicians for the management of acute deep-vein thrombosis and pulmonary embolism has been anticoagulation. This fo...
TL;DR: The dermatological and histological aspects of this tumor suggest a highly malignant undifferentiated process, but the biological behavior seems to be of a low‐grade malignancy.
Abstract: Clinical, microscopic, ultrastructural, and histochemical characteristics of a primary cutaneous tumor, identified as an APUDoma possibly arising from Merkel cells, are presented. The tumor can be diagnosed by means of routine histology. In some cases the argyrophylic staining technique can be helpful. The dermatological and histological aspects of this tumor suggest a highly malignant undifferentiated process. The biological behavior of this tumor, however, seems to be of a low-grade malignancy. It is therefore important to recognize it from undifferentiated, highly malignant, mostly metastatic processes in the skin. There is also a summary of the clinical history and microscopic findings of identical tumors in 4 other patients.
TL;DR: A detailed description of the morphology and the complex melting behavior of poly(ethylene terephthalate) crystallized isothermally in the range 100-245°C is presented in this article.
Abstract: A detailed description of the morphology and the complex melting behavior of poly(ethylene terephthalate) crystallized isothermally in the range 100–245°C is presented. Double or single melting endotherms can deliberately be obtained by varying the heating rate in the differential scanning calorimeter (DSC). In the case of double melting peaks, the first endotherm (I) corresponds to the melting of the crystalline material formed at the crystallization temperature Tc. The second melting endotherm (II) originates from the melting of a fraction of the original crystalline material reorganized during the DSC scan. The appearance of one melting endotherm (I or II) relates to the melting of the original structure or the melting of a completely transformed structure. Taking the end of the melting endotherm I as the final melting temperature TM of the material, an equilibrium melting temperature of 290°C is obtained from a plot of TM vs. Tc. A detailed morphological study of the isothermally crystallized samples by electron microscopy and both small-angle and wide-angle x-ray scattering raises questions about the use of the two-phase concept in relating morphological parameters and melting behavior at low crystallization temperatures.
TL;DR: Peritoneal fluid appears to be predominantly an ovarian exudate, neither an exudates from the pelvic peritoneum nor a tubal secretion, which is not affected by pelvic varicose veins, a visible corpus luteum or an ovulation stigma.
TL;DR: The present study with light and electron microscopes was carried out on the spiral arteries during the second trimester of normal human pregnancy, with special attention given to the intravascular migration of trophoblast, as well as to the consequent interaction between fetal and maternal tissues.
01 Jan 1980
TL;DR: A highly significant correlation was demonstrated between pKd and pKa (or pKi) values, suggesting that the detected binding sites are the physiological receptors involved in the glycogenolytic action of vasopressin on the rat liver.
Abstract: Specific vasopressin binding to rat hepatocytes and rat liver membranes was measured using biologically active (3H)-Tyr2-Lys8-vaso-pressin (8.5 Ci/mM). In both systems, vasopressin binding was found to be time-dependent, reversible, and saturable. The kinetic parameters for vasopressin binding were: apparent dissociation constants (Kd): 4.9 nM and 15 nM; maximal binding capacities: 0.83 pmoles/mg protein and 2.105 sites/Cell for purified membranes and intact cells respectively. The relative affinities of 19 vasopressin structural analogues were deduced from competition experiments and compared to the previously determined glycogenolytic (or anti-glycogenolytic) potencies of these analogues. For both agonists and antagonists, a highly significant correlation was demonstrated between pKd and pKa (or pKi) values, suggesting that the detected binding sites are the physiological receptors involved in the glycogenolytic action of vasopressin on the rat liver. The affinity of antagonists for binding to t...
TL;DR: The abnormal serum concentrations of 1,25-dihydroxyvitamin D3 in thyroid disorders cannot be explained by differences in serum binding because the serum vitamin D-binding protein was unaltered in hyperthyroid subjects and only slightly increased (+17%) in hypothyroid subjects.
Abstract: The serum concentrations of parathyroid hormone, 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 were measured in patients with untreated thyroid disorders. The serum concentration of parathyroid hormone was decreased in hyperthyroidism [20 +/- 10 mU/liter, (mean +/- SD); n =23; P < 0.01] and increased in hypothyroidism (53 +/- 17 mU/liter; n = 12; P < 0.001) compared to that in normal subjects (26 +/- 9 mU/liter; n = 81). The concentration of 25-hydroxyvitamin D3 was not altered, but the concentration of 1,25-dihydroxyvitamin D3 was significantly lower in the serum of hyperthyroid patients (28 +/- 11 ng/liter) than in the serum of normal subjects (42 +/- 13 ng/liter). On the contrary, an increased concentration of 1,25-dihydroxyvitamin D3 was observed in the serum of hypothyroid patients (73 +/- 28 ng/liter; P < 0.001 vs. normal subjects). The abnormal serum concentrations of 1,25-dihydroxyvitamin D3 in thyroid disorders cannot be explained by differences in serum binding because the serum vitamin D-binding protein was unaltered in hyperthyroid subjects and only slightly increased (+17%) in hypothyroid subjects. These changes in the serum concentration of 1,25-dihydroxyvitamin D3 are compatible with previous data on altered intestinal calcium absorption in thyroid disorders.
TL;DR: The CPG/ethylene glycol‐purified γ‐type interferon preparation was found to inhibit the growth of certain lymphoblastoid cells and potentiated natural killer activity of fresh donor lymphocytes, and was not significantly more active than preparations of a and β‐interferon of similar antiviral potency.
Abstract: Interferon was induced in leukocyte suspensions from human buffy coats by exposure to phytohemagglutinin P, concanavalin A (Con A) and staphylococcal enterotoxin A, under a variety of cell culture conditions. Con A was found to rapidly (within 12 h) induce high yields of antiviral activity (1.5 units/1000 cells). Lesser yields were obtained with the other two mitogens studied. The interferon was partially purified to a spec. act. around 10(5.3) units/mg protein, by batch adsorption on controlled-pore glass (CPG) beads and desorption by ethylene glycol. This material was characterized as containing mainly gamma-type interferon. Specifically on gel filtration, a fraction of 45000 daltons was obtained which could account for virtually all antiviral activity present in the starting material. Furthermore, the ethylene glycol-eluted antiviral activity was acid-labile, serologically distinct from alpha and beta-type interferon and strictly species-specific (no activity detectable on any of the available cell species sensitive to alpha and beta-type interferon). The crude culture supernatant also contained some antiviral activity which resembled beta-type interferon in that it adsorbed to CPG, could be desorbed by pH 2 buffer, was acid-resistant and could be neutralized by a specific anti-fibroblast interferon antiserum. The CPG/ethylene glycol-purified gamma-type interefron preparation was found to inhibit the growth of certain lymphoblastoid cells (Daudi and Molt-4). It also potentiated natural killer activity of fresh donor lymphocytes. In both respects, the gamma-type interferon preparation was not significantly more active than preparations of alpha and beta-interferon of similar antiviral potency.
TL;DR: The genetic heterogeneity of the human and rat vitamin D-binding protein did not affect its affinity or capacity for both vitamin D metabolites.
TL;DR: In this paper, external steel reinforcements are used for restoring and repairing concrete structures, where the external steel is glued to the concrete with an epoxy adhesive and the joints are usually loaded in pure shear or in bending shear.
TL;DR: The results indicate that the bile acid output into the duodenum during the interdigestive phase in fluctuating in accordance with the interDigestive motility complex.
TL;DR: In this article, the transformation laws of chiral superfields with arbitrary Weyl weight w are determined for the U(2) superconformal theory, and a super-conformally invariant density is given for fields with w = 2.
01 Apr 1980
TL;DR: In this article, the Darcy-Weisbach friction coefficient for thin sheet flows was calculated from the unit discharge and the depth, and not from measurements of the surface velocity, and a good approximation of the steady state depth is obtained when the recording balance is fixed to its bottom end.
Abstract: Shallow water depths on steep slopes of as much as fifty per cent can be measured easily by weighing a light flume and the water it contains. Because water accelerates along the flume, a good approximation of the steady state depth is obtained when the recording balance is fixed to its bottom end.
From the unit discharge and the depth, and not from measurements of the surface velocity, the Darcy-Weisbach friction coefficient can be calculated. The present results show that this friction coefficient is larger in thin sheet flows than that calculated from the equation for rough turbulent flow. This latter could fit at a Reynolds Number of 50,000. When the regime is laminar (Re < 2,440) the Darcy-Weisbach friction coefficient always exceeds the theoretical value of 96/Re. The great relative depth of standing and travelling waves could account for this discrepancy together with turbulence and wake formation around bottom grains.
Herein it is assumed that a regime can prevail where a laminar superlayer glides over a turbulent sublayer in the vicinity of bottom grains, because the ratio of the surface velocity to the mean velocity can greatly exceed 1.5, especially on steep slopes.
Until photographs of the streamlines are taken, no statement about flow regimes in supercritical sheet flow can be made.
TL;DR: It is suggested that the assay of progesterone and 17β‐oestradiol in peritoneal fluid should be done in all women with infertility and biphasic basal body temperature charts in order to diagnose the luteinized unruptured follicle syndrome.
TL;DR: Based on the differences in the antigenicity, morphology, and lectin sensitivity between these six variants and established Naegleria species, it is proposed that they should be established as a new species.
TL;DR: In this article, a method for simultaneous measurement of bandgap narrowing and diffusion length in a heavily doped n+substrate is proposed, which uses planar test pattern at the front side of the substrate to determine the hole minority-carrier current injected from a p-type emitter and diodes at the rear side to measure diffusion length.
Abstract: A new method for simultaneous measurement of bandgap narrowing and diffusion length in a heavily doped n+substrate is proposed. The method uses planar test pattern at the front side of the substrate to determine the hole minority-carrier current injected from a p-type emitter and diodes at the rear side to measure diffusion lengths. The method can be generalized such that the minority-carrier diffusion constant can be estimated and the use of extrapolated literature data can be avoided. Results of measured values of bandgap narrowing and diffusion length versus impurity concentration are given for n-type material.