Showing papers by "University of Amsterdam published in 1980"
TL;DR: In this article, a semi-empirical model of alloy cohesion involving two material constants for each element is introduced by means of the physical ideas underlying the scheme and the resulting expressions for the heat of formation of binary alloys are presented and their applicability in various extreme situations is discussed.
Abstract: A semi-empirical model of alloy cohesion involving two material constants for each element is introduced by means of the physical ideas underlying the scheme The resulting expressions for the heat of formation of binary alloys are presented and their applicability in various extreme situations is discussed The model is shown to reproduce a vast amount of experimental information on the sign of heats of formation Detailed comparison with experiment for particular classes of alloys will be presented in the sequels to this paper
932 citations
TL;DR: In this article, the authors discuss single molecule properties and intermolecular interactions and discuss in detail the ortho-para properties, conversion and diffusion, followed by a description of the crystal structures and the orientational ordering phenomena.
Abstract: The molecular hydrogens (${\mathrm{H}}_{2}$, ${\mathrm{D}}_{2}$, HD, etc.) form the simplest of all molecular solids. The combination of the light mass, small moment of inertia, weak interactions, and the quasi-metastable ortho-para species result in a fascinating low-temperature behavior that can be understood to a large extent from considerations of first principles. After discussing single molecule properties and intermolecular interactions we discuss in detail the ortho-para properties, conversion and diffusion. This is followed by a description of the crystal structures and the orientational ordering phenomena. The thermodynamic properties are reviewed. The article is concluded with a discussion of the translational ground state of the solid and the effect of the large zero-point motion on the solid state properties. A large number of data are collected in tables and graphs to provide a reference source.
912 citations
Book•
28 Nov 1980TL;DR: In this paper, an examination of the nature of economic explanation is presented, where the authors introduce current thinking in the philosophy of science and review the literature on methodology, and then turn to the troublesome question of the logical status of welfare economics, giving the reader an understanding of the outstanding issues in economics.
Abstract: This book is an examination of the nature of economic explanation. The opening chapters introduce current thinking in the philosophy of science and review the literature on methodology. Professor Blaug then turns to the troublesome question of the logical status of welfare economics, giving the reader an understanding of the outstanding issues in the methodology of economics. This is followed by a series of case studies of leading economic controversies, which shows how controversies in economics may be illuminated by paying attention to questions of methodology. A final chapter draws the strands together and gives the author's view of what is wrong with modern economics. This book is a revised and updated edition of a classic work on the methodology of economics, in which Professor Blaug develops his discussion of the latest developments in macroeconomics, general equilibrium theory and international trade theory. A new section on the rationality postulate is also added.
610 citations
TL;DR: Analysis of DNA modification in the human γδβ-globin gene region suggests that a low level of DNA methylation may be a necessary, but not a sufficient, condition for gene expression in higher eucaryotes.
540 citations
TL;DR: Although these ceramics have high compressive strengths, they are not suitable for joint replacements, and Prevention of alveolar ridge resorption is a promising concept, and space-filling and use of aids for jaw-bone enlargement are proposed for routine clinical application.
474 citations
TL;DR: In this paper, a section more than 3 m deep from Denekamp, The Netherlands, which included part of the Younger Dryas and almost the whole of the Holocene, was studied by analysing the micro- and macro-fossils per 0.8 cm in order to obtain maximum information regarding the regional and local vegetational succession and any climatic changes that might have taken place during that time interval.
467 citations
TL;DR: The method is shown to be stable and for a large class of matrices it is, asymptotically, faster by an order of magnitude than theQR method.
Abstract: A method is given for calculating the eigenvalues of a symmetric tridiagonal matrix The method is shown to be stable and for a large class of matrices it is, asymptotically, faster by an order of magnitude than theQR method
404 citations
TL;DR: A new method has been developed for the detection of in situ hybridization by fluorescence microscopy based on the covalent binding of commercially available fluorochromes to the 3′-terminus of RNA.
311 citations
TL;DR: The S-S model has been experimentally validated in terms of thousands of k′ measurements, for hundreds of different solutes and solvents, and it has been applied in polar-bonded-phase liquid chromatography and to gas-solid chromatography, especially as regards solvent selectivity effects.
271 citations
TL;DR: In this article, the course of filling-in and subsequent bog development of a brackish eutrophic lake is analyzed by means of investigations of pollen, spores, algae, fungal remains, diatoms and plant macrofossils.
253 citations
TL;DR: It was concluded that dense apatite ceramics are fully compatible with the tibia of the rat and that no degradation of the implant material occurred for intervals of up to 6 months after implantation.
Abstract: Dense (97-99.9%) hydroxylapatite ceramics were implanted in muscle and bone tissue of rats. The aim of this study was to compare apatite implant material made of commercially available powder with laboratory powder prepared in a painstaking manner. Biocompatibility, biostability, and adherence to bone were evaluated. In muscle tissue the implants were found to be encapsulated with a very thin connective tissue layer. Implantation in excavated bone tissue resulted with new bone directly deposited against the implant surface, irrespective of the type of hydroxylapatite used. When the implants were protruding from the bone surface, bone appeared to grow up to the edge of the protruding part of the implant. A very strong bonding developed; push-out tests indicated that the bone fractured but never at the interface. Histologic studies proved that a sleeve of newly formed bone closely encased the implant, regardless of shape. It was concluded that dense apatite ceramics are fully compatible with the tibia of the rat and that no degradation of the implant material occurred for intervals of up to 6 months after implantation. The very strong bonding without mechanical retention indicated continuity between artificial hydroxylapatite and natural bone. No difference was found between the biological behavior of the hydroxylapatites prepared from commercial or laboratory starting powders.
TL;DR: In this paper, a literature search through Chemical Abstracts and the Science Citation Index is performed to find chemical and electrochemical aspects of the glassy carbon/electrolyte interface for both aqueous solutions and non-aqueous electrolytes.
TL;DR: An immunofluorescence test on paraformaldehyde‐fixed platelets in suspension was used for the detection of antibodies on platelets and in the sera of patients with idiopathic or secondary thrombocytopenia.
Abstract: Summary An immunofluorescence test on paraformaldehyde-fixed platelets in suspension was used for the detection of antibodies on platelets and in the sera of patients with idiopathic or secondary thrombocytopenia.
In idiopathic thrombocytopenia, a positive test was found on the patients' platelets in 55 out of 80 cases. The indirect immunofluorescence test with the patient's serum was positive in 28 out of 80 cases. In thrombocytopenia accompanied by other autoimmune diseases, the direct test was positive in 35 out of 39; the indirect test in 13 out of 39 patients. These results are similar to those obtained with other techniques recently described in the literature.
By using FITC-labelled monospecific anti-immunoglobulin reagents, immunochemical characterization of the autoantibodies was possible. Of the 90 patients with a positive direct test, 80 were analysed in this way. Of these, platelet-bound IgG was detected in 76. This was accompanied by IgM in 17 and IgA in three. In four, only IgM was found. The IgG subclasses of platelet-bound IgG were studied in 48 patients. Mainly IgG1 was found (45), often together with IgG3 (22) or IgG4 (14), but rarely with IgG2 (1). Only a few patients had just IgG3 (2) or IgG4 (1) on their platelets.
Platelet-bound autoantibodies could often be eluted (41 out of 86 cases) with ether and were demonstrable in the eluate with the indirect immunofluorescence test. This test was usually positive when the direct test was strongly positive (40 out of 44) and usually negative when it was weakly positive (1 out of 24) or negative (1 out of 18).
TL;DR: In the Netherlands, where land for disposal is scarce, the percentage of refuse which is incinerated has increased steadily from 15% in 1960 to 34% in 1978 as a replacement of l and f i l l (see Table I ) (I ).
TL;DR: 11S and 18S fractions of yeast mitochondrial RNAs, isolated by electrophoresis through agarose gels, have been found by electron microscopy to contain approximately 50% circular molecules, and it is concluded that they are covalently closed.
TL;DR: Cloned DNA complementary to the messenger RNAs for four immunologically distinct VSGs are cloned and hybridised these complementary DNAs with restriction digests of T. brucei nuclear DNA and infer that activation of a VSG gene involves the production of an expression-linked copy of that gene.
Abstract: Pathogenic African trypanosomes evade the immune system of their mammalian hosts by the sequential expression of alternative cell-surface glycoproteins (reviewed in refs 1,2). Variant surface glycoproteins (VSGs) purified from cloned variants of Trypanosoma brucei have similar molecular weights (about 60,000), but differ in amino acid composition, N-terminal amino acid sequence and C-terminal structure. We have cloned DNA complementary to the messenger RNA's for four immunologically distinct VSGs and hybridised these complementary DNAs (cDNAs) with restriction digests of T. brucei nuclear DNA, fractionated by gel electrophoresis and transferred to nitrocellulose strips. Each cDNA recognises a unique set of fragments and this basic set is present unaltered in the nuclear DNAs from the four variants. In addition, each probe recognises an extra fragment only in nuclear DNA isolated from cells expressing the VSG corresponding to the cDNA probe. We infer that activation of a VSG gene involves the production of an expression-linked copy of that gene.
TL;DR: In this article, the authors investigate polychlorinated dibenzo-p-dioxins (PCDD) and related compounds in the fly ash and flue gasses of some municipal incinerators in the Netherlands.
TL;DR: The results obtained suggest a subclassification of postsynaptic alpha-adrenoceptors into alpha 1- and alpha 2-subtypes mediating pressor effects, and yohimbine an antagonist of post Synaptic alpha 2 -adrenOceptors and phentolamine behaves as a non-selective antagonist.
TL;DR: Atomic hydrogen has been stabilized at temperatures of 270 mK and magnetic fields up to 7 T as discussed by the authors. But it has no measurable decrease in density after 532 sec. Covering of exposed surfaces with a film of $^{4}mathrm{He$ is essential.
Abstract: Atomic hydrogen has been stabilized at temperatures of 270\ifmmode\pm\else\textpm\fi{}20 mK and in magnetic fields up to 7 T. It is believed to be gaseous. A sample displayed no measurable decrease in density after 532 sec. Covering of exposed surfaces with a film of $^{4}\mathrm{He}$ is essential.
TL;DR: This hereditary disease is shown to be the result of a deletion of at least 40,000 base pairs of the γδβ -globin gene locus, which results in a severe anaemia in newborns which subsequently develops into a β-thalassaemia syndrome in adult life.
Abstract: In gamma-beta-thalassaemia, human gamma- and beta-globin gene expression is suppressed; this results in a severe anaemia in newborns which subsequently develops into a beta-thalassaemia syndrome in adult life. This hereditary disease is now shown to be the result of a deletion of at least 40,000 base pairs of the gammadeltabeta-globin gene locus. The gamma- and delta-globin genes are deleted in the affected chromosome but, surprisingly, the beta-globin gene is still present, together with a large segment of the DNA sequences flanking the gene on its 5'-side and the entire region on the 3'-side of the gene. Hence, a deletion of DNA far from the beta-globin gene results in the suppression of its activity.
TL;DR: The results show that in a restricted group of patients with pulmonary vascular disease, a biopsy of the lung has a place in establishing the nature and severity of the vascular alterations.
TL;DR: A family is described in which the mother developed platelet‐specific antibodies, not directed against the antigens of the Zw(PlA) or the KO system, and proved to be mainly IgGl antibodies, although weak IgM antibodies of the same specificity were also detected.
Abstract: A family is described in which the mother developed platelet-specific antibodies, not directed against the antigens of the Zw(PlA) or the Ko system. The antibodies were only detectable in the immumofluorescence test and the radioactive antiglobulin test on platelets, and proved to be mainly IgG1 antibodies, although weak IgM antibodies of the same specificity were also detected. By cross-absorption studies, investigation of the family and a small-scale population study, it appeared that the antibodies were directed against a new antigen which we have called Baka. The frequency of the Baka phenotype in the Dutch population was 90.76%, the calculated genotype frequency 0.696. The Baka phenotype was neither sex-linked nor, so far as evaluable, closely linked to other platelet, red-cell, granulocyte, or HLA groups. The first child of this mother died of neonatal thrombocytopenia, the second child was unaffected. During the second pregnancy, the titre of the antibodies did not rise. The platelets of this child were found not to carry the Baka antigen.
TL;DR: It is shown that DNA from an individual heterozygous for the Greek (A gamma) type of HPFH shows no detectable deletion in the entire gamma delta beta-globin gene region, and HPFH appears to occur in different molecular forms.
Abstract: We have mapped the globin gene region in the DNA of two HPFH patients. In a patient homozygous for the G gamma A gamma type of HPFH at least 24 kb of DNA in the globin gene region has been deleted to remove most of the gamma-delta intergenic region and the delta and beta globin genes. The 5' break point of the deletion is located about 9 kb upstream from the delta globin gene. The 3' break point has not been precisely located but is at least 7 kb past the beta globin gene. DNA from an individual heterozygous for the Greek (A gamma) type of HPFH, however, shows no detectable deletion in the entire gamma delta beta-globin gene region. HPFH, therefore, appears to occur in different molecular forms. These results are discussed in terms of a model for the regulation of globin gene expression in man.
TL;DR: In this article, a mineral medium containing 1% of glucose as the main carbon source was subjected to one-phase and two-phase anaerobic digestion processes under comparable conditions.
TL;DR: The spectral changes caused by the addition of halides to myeloperoxidase have been investigated and the dissociation constants of the enzyme-halide complexes have been determined and it is shown that at low pH, chloride acts as a competitive inhibitor with respect to H2O2, whereas at higher pH, H2 O2 inhibits the chlorination reaction.
TL;DR: It is concluded that in bloodstream form T. brucei the glycolytic intermediates are present in the glycosomes as well as in the cytosol and that the two pools of intermediates equilibrate with each other, despite the presence of the Glycosomal membrane.
Abstract: The possibility that the glycosomes present in the bloodstream form of Trypanosoma brucei [Opperdoes, F. R. and Borst, P. (1977) FEBS Lett. 80, 360--364] constitute a separate pool of glycolytic intermediates within the cell was investigated. In titrations of intact cells with digitonin, a differential activation of glycolytic enzymes was observed. Enolase, pyruvate kinase and the cell-sap marker alanine aminotransferase were activated at 0.05 mg digitonin per mg protein. The nine glycosomal enzymes involved in the conversion of glucose and glycerol into 3-phosphoglycerate were activated only at digitonin concentrations between 0.7 and 9.8 mg/mg protein. In subcellular fractions the activities of the latter enzymes were all latent between 70 and 92%. Latency was abolished by addition of 0.1% Triton X-100 or partly by five cycles of freezing and thawing. We conclude that the glycosomal enzymes are surrounded by a membrane, which forms a permeability barrier to intermediates and co-factors of glycolysis. The concentrations of glycolytic intermediates and of adenine nucleotides were measured under aerobic conditions as well as in the presence of 1 mM salicylhydroxamic acid, a respiratory inhibitor. Addition of salicylhydroxamic acid caused the following changes: (a) The levels of almost all glycolytic intermediates measured decreased. Glycerol-3-phosphate, however, increased fourfold. (b) The phosphate potential was drastically lowered from 2900 to 450 M-1. (c) The trypanosomes became more reduced, as monitored by a change in the apparent redox state of the NADH/NAD+ courple from E'h = -189 to E'h = -219 mV. From the high levels of metabolite concentrations found and from comparison of the apparent mass-action ratios calculated for the separate glycolytic reactions with those for other organisms, we conclude that in bloodstream form T. brucei the glycolytic intermediates are present in the glycosomes as well as in the cytosol and that the two pools of intermediates equilibrate with each other, despite the presence of the glycosomal membrane.
TL;DR: Vasopressin and oxytocin were specifically demonstrated in the rat brain using the unlabelled antibody-enzyme method and purification of the first antiserum to propose the proposed presence of vasotocin in the pineal gland.
Abstract: Vasopressin and oxytocin were specifically demonstrated in the rat brain using the unlabelled antibody-enzyme method and purification of the first antiserum. Vasopressin and oxytocin fibres extend via the subcommissural organ or habenular commissure into the pineal stalk and terminate in the anterior part of the pineal organ. In addition, immediately adjacent to the subsommissural organ many vasopressin-containing fibres run caudally toward the central grey. These results are discussed in relation to the proposed presence of vasotocin in the pineal gland.
TL;DR: An immunoperoxidase method has been developed which allows accurate and sensitive quantitation of the binding of monoclonal antibodies to cell surface antigens and results obtained with several monoclotal antibodies with specificity for different target cells are shown.
TL;DR: It is concluded from this lack of cross-hybridization that antigenic diversity in trypanosomes, unlike antibody diversity in mammals, does not involve the linkage of a repertoire of genes for the variable N-terminal half to a single gene for the C-terminals of the VSGs.
TL;DR: In this article, the pharmacokinetics following a bolus injection of fentanyl 60 μg kg−1 as the sole anaesthetic in five patients undergoing cardiac surgery are described, and the authors describe a biexponenrial decay curve with an initial half-life of 1.7±0.85 min and a half life during the tissue uptake phase of 69±8.2 min.
Abstract: SUMMARY The pharmacokinetics following a bolus injection of fentanyl 60 μg kg−1 as the sole anaesthetic in five patients undergoing cardiac surgery are described. Before cardiopulmonary bypass the kinetics can be described by a biexponenrial decay curve with an initial half-life of 1.7±0.85 min and a half-life during the tissue uptake phase of 69±8.2 min. Two patients had secondary peaks in plasma fentanyl concentration during the first 5 min after injection. After 5 min cardiopulmonary bypass with haemodilution, the fentanyl concentration decreased by an average of 53%. The half-life in the post-bypass elimination phase was 423±36.9 min. No second peaks during the elimination phase were found.