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Showing papers by "University of Geneva published in 1983"


Journal ArticleDOI
TL;DR: In this article, the role of dynamic swelling and the dissolution of the polymer matrix on the release mechanism was discussed, as well as the effect of the tracer/excipient ratio on the poly(vinyl alcohol) release profile.

4,397 citations



Journal ArticleDOI
TL;DR: In this paper, the three Judd-Ofelt intensity parameters for erbium(III) are given in 17 different environments, and the effect of covalent chemical bonding on the intensity is discussed.
Abstract: The three Judd-Ofelt intensity parameters for erbium(III) are given in 17 different environments. The Ω 2 parameter is strongly affected by covalent chemical bonding. In contrast, the Ω 6 parameter is related to the rigidity of the medium in which the ions are situated.

624 citations


Journal ArticleDOI
01 Jul 1983-Science
TL;DR: The DNA of the bithorax complex has been isolated, and a region of 195,000 base pairs that covers the left half of the complex is described here.
Abstract: The bithorax complex in Drosophila melanogaster is a cluster of homeotic genes that specify developmental pathways for many of the body segments of the fly. The DNA of the bithorax complex has been isolated, and a region of 195,000 base pairs that covers the left half of the complex is described here. The lesions associated with many of the bithorax complex mutants have been identified, and most are due to DNA rearrangements. Most of the spontaneous mutants have insertions of a particular mobile element named "gypsy." This element affects the functions of sequences removed from the site of insertion. Mutant lesions for a given phenotypic class are distributed over large DNA distances of up to 73,000 base pairs.

546 citations


Journal ArticleDOI
TL;DR: The release of potassium chloride from hydroxypropyl methylcellulose matrices was investigated for tablets prepared with several different compression forces and it was determined that the release kinetics for these systems deviates significantly from the classical t1/2 dependence.

322 citations


Journal ArticleDOI
TL;DR: Using a lacI-Z fusion system, the efficiency of suppression of nonsense codons in the I gene of Escherichia coli is determined by assaying beta-galactosidase activity and models explaining the effect of the surrounding sequence on suppression efficiency are considered.

257 citations


Journal ArticleDOI
TL;DR: In this paper, a method of deriving the first power corrections (1/Q 2 ) to the leptoproduction structure functions is presented, based directly on the manipulation of Feynman diagrams, in which the transverse components of momenta and the gluon field control both kinematic and dynamical power corrections.

243 citations


Journal ArticleDOI
TL;DR: At least three polymorphic class II antigens are encoded in the human major histocompatibility complex (HLA): DR, DC and SB, and at least two non‐allelic DR beta chain genes exist.
Abstract: At least three polymorphic class II antigens are encoded in the human major histocompatibility complex (HLA): DR, DC and SB. cDNA clones encoding beta chains of HLA-DR antigen, derived from mRNA of a heterozygous B-cell line, were isolated and could be divided into four subsets, clearly distinct from cDNA clones encoding DC beta chains. Therefore, at least two non-allelic DR beta chain genes exist. The complete sequence of one of the DR beta chain cDNA clones is presented. It defines a putative signal sequence, two extracellular domains, a trans-membrane region and a cytoplasmic tail. Comparison with a DC beta chain cDNA clone revealed a homology of 70% between the two beta chains and that the two genes diverged under relatively little selective pressure. A set of amino acids conserved in immunoglobulin molecules was found to be identical in both DR and DC beta chains. Comparison of the DR beta chain sequence with the amino acid sequence of another DR beta chain revealed a homology of 87% and that most differences are single amino acid substitutions. Allelic polymorphism in DR beta chains has probably not arisen by changes in long blocks of sequence.

237 citations


Journal ArticleDOI
01 Dec 1983-Cell
TL;DR: Sequence homologies at the beginning of three Sendai virus cistrons suggest that these genes may have arisen by duplication from a common ancestor, possibly an influenza-like virus gene.

215 citations


Journal ArticleDOI
01 Feb 1983-Cell
TL;DR: Examination of known leader RNA sequences suggests that the sequence responsible for selective assembly by N protein is a five-times-repeated A residue at every third position from the 5' end of the leader chain.

196 citations


Journal ArticleDOI
TL;DR: These observations confirm the existence of two qualitatively distinct Golgi subcompartments, show that the lectin conjugates can be employed as relatively proximal or distal Golgi markers under conditions of excellent ultrastructural preservation, and suggest that the asymmetric distribution of qualitatively different oligosaccharides is a property of underlying cellular components.
Abstract: We investigated the subcellular sites of glycoprotein oligosaccharide maturation by using lectin conjugates to stain lightly-fixed, saponin-permeabilized myeloma cells At the electron microscopic level, concanavalin A-peroxidase stains the cisternal space of the nuclear envelope, the rough endoplasmic reticulum, and cisternae along the proximal face of the Golgi stack Conversely, wheat germ agglutinin-peroxidase stains cisternae along the distal face of the Golgi stack, associated vesicles, and the cell surface These observations confirm the existence of two qualitatively distinct Golgi subcompartments, show that the lectin conjugates can be employed as relatively proximal or distal Golgi markers under conditions of excellent ultrastructural preservation, suggest that the asymmetric distribution of qualitatively distinct oligosaccharides is a property of underlying cellular components and not simply of the principal secretory product, and suggest that the oligosaccharide structure recognized by wheat germ agglutinin is attained during transport from the proximal toward the distal face of the Golgi stack

Journal ArticleDOI
TL;DR: Investigation of the hydrophilic/hydrophobic characteristics of the four polypeptides of Drosophila melanogaster revealed the presence of an alpha-helical region of very prominent local hydrophilicity, which probably represents a surface structural domain common to each protein.

Journal ArticleDOI
TL;DR: In this article, a sufficient condition for a unimodal map of the interval to have an invariant measure absolutely continuous with respect to the Lebesgue measure was given, and the condition requires positivity of the forward and backward Liapunov exponent of the critical point.
Abstract: We give a sufficient condition for a unimodal map of the interval to have an invariant measure absolutely continuous with respect to the Lebesgue measure. Apart from some weak regularity assumptions, the condition requires positivity of the forward and backward Liapunov exponent of the critical point.

Journal ArticleDOI
TL;DR: Although the present documentation method is actively recommended it is hoped that it will help supply some of the common language and syntax that qualitative researchers will need in elaborating a well documented and credible methodology.
Abstract: Several major points are made about techniques of data reduction. 1) Data reduction or data transformation occurs at all points in a study from design to data collection and write-up. It is analysis of a form which organizes and clarifies data in such a way that final analysis can occur coherently. 2) Data reduction and data analysis have as an indispensable accompaniment some form of data display and the display modes chosen will inevitably condition the processes and conclusions for analysis. The most frequently adopted and typical display mode for qualitative data the narrative text is also the most cumbersome. Matrices and figures of several sorts can be generated that meet the need to display data coherently and compactly. 3) Single-site and multisite analytical processes are complex but not arcane or obscure. 4) It is possible to understand processes if they have been documented accurately using some reasonably standardized scheme. Such documentation permits an external audit it allows reproducibility of findings and replicability of studies; it can support dialogue among researchers struggling with qualitative analysis that can lead to something resembling shared methodological canons. However methodological canons also result in endless refinement of effort intense socialization of novitiates into a received orthodoxy and preoccupation with methods rather than the substance of inquiry. Nevertheless self-documentation is labor-intensive and not a total substitute for verbal elaboration. Filling out forms usually takes at least 15% of the total analysis time. Thus although the present documentation method is actively recommended it is hoped that it will help supply some of the common language and syntax that qualitative researchers will need in elaborating a well documented and credible methodology.

Journal ArticleDOI
TL;DR: The pick-up head of a magnetic tape player is demagnetized by a moving, alternating magnetic field generated within the front end portion of a cartridge-type housing inserted into the player as discussed by the authors.
Abstract: The pick-up head of a magnetic tape player is demagnetized by a moving, alternating magnetic field generated within the front end portion of a cartridge-type housing inserted into the player. The drive capstan of the player drives a carrier on which magnets are mounted to produce said alternating magnetic field. The carrier is reciprocated through a predetermined stroke relative to the pick-up head by an actuating mechanism.

Journal ArticleDOI
B. Cochet1, A Jung1, Griessen M1, P. Bartholdi1, P Schaller1, A. Donath1 
TL;DR: In this article, the effect of lactose on intestinal calcium absorption was studied in 12 normal-lactase subjects and 7 lactase-deficient subjects, with or without the presence of an oral load of 50 g of lactic acid in each subject.

Journal ArticleDOI
01 Oct 1983-Gene
TL;DR: A cosmid cloning system has been developed which is useful for the construction of genomic libraries and the introduction of clones into a broad range of bacterial species, and the genes specifying myo-inositol transport from Pseudomonas strain JD34 have been cloned with this system.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the low and medium-temperature specific heat of 25 samples based on eleven $A15$ binary compounds, with values ranging from less than 0.015 to 18 K.
Abstract: We analyze the low- and medium-temperature specific heat of 25 samples based on eleven $A15$ binary compounds, with ${T}_{c}$'s ranging from less than 0.015 to 18 K. Experimentally determined "moments" of the phonon spectra ($\overline{\ensuremath{\omega}}$,${\overline{\ensuremath{\omega}}}_{2}$,${\ensuremath{\omega}}_{log}$) are included in the analysis. Values are tabulated for ${\overline{T}}_{c}$, ${\overline{\ensuremath{\alpha}}}^{2}$, $\ensuremath{\eta}$, $〈{I}^{2}〉$, ${N}_{\mathrm{bs}}({E}_{F})$, $M{\overline{\ensuremath{\omega}}}_{2}^{2}$, ${H}_{c}(0)$, and $\frac{2\ensuremath{\Delta}(0)}{{k}_{B}{T}_{c}}$. We note the following: (i) The Debye temperature is generally a bad estimate of ${\ensuremath{\omega}}_{log}$. (ii) $\ensuremath{\lambda}$ is governed mainly by the "electronic parameter" $\ensuremath{\eta}$; $\ensuremath{\lambda}=0.175\ensuremath{\eta}(\mathrm{eV}/{\AA{}}^{2})\ifmmode\pm\else\textpm\fi{}0.2$ for all $A15$ compounds studied. (iii) $\ensuremath{\eta}$ is proportional to the density of states at the Fermi level and this density of states agrees well with band-structure calculations of Jarlborg in Nb-based compounds. In V-based compounds, the observed bad correlation may reflect the presence of spin fluctuations. (iv) The values for the reduced gap $\frac{2\ensuremath{\Delta}(0)}{{k}_{B}{T}_{c}}$ range from 3.4 to 4.9 and they are correlated with $\frac{{T}_{c}}{{\ensuremath{\omega}}_{log}}$.

Journal ArticleDOI
TL;DR: In this article, the authors studied the effect on the transposition activity of IS1 of the position and orientation of the element in the donor replicon of the transposon Tn9.

Journal ArticleDOI
TL;DR: In this article, the exceptional polymorphism of La${\mathrm{Ir}}_{2}$${\mathm{Si}}-2}$ is discussed, emphasizing structural relationships and the occurrence of superconductivity in the high-temperature modification.
Abstract: La${\mathrm{Ir}}_{2}$${\mathrm{Si}}_{2}$ has a high-temperature form crystallizing in the primitive tetragonal Ca${\mathrm{Be}}_{2}$${\mathrm{Ge}}_{2}$-type structure (space group $\frac{P4}{\mathrm{nmm}}$; $a=4.191$ \AA{}, $c=9.944$ \AA{}), and a low-temperature form of the body-centered tetragonal Th${\mathrm{Cr}}_{2}$${\mathrm{Si}}_{2}$ type (space group $\frac{I4}{\mathrm{mmm}}$; $a=4.109$ \AA{}, $c=10.299$ \AA{}). Both structures are Ba${\mathrm{Al}}_{4}$-type derivatives. The high-temperature modification may be quenched from above the transformation temperature of 1720\ifmmode^\circ\else\textdegree\fi{}C and becomes superconducting at 1.6 K, while the low-temperature modification is normal down to 1 K. The structures of both modifications have been refined in single-crystal studies. The exceptional polymorphism of La${\mathrm{Ir}}_{2}$${\mathrm{Si}}_{2}$ is discussed, emphasizing structural relationships and the occurrence of superconductivity in the high-temperature modification.

Journal ArticleDOI
TL;DR: In this article, the axial-vector to vector form factor ratio |g1/f1| = 0.34 ± 0.05 was obtained for the Σ− decay vertex and from the impact point measured in a neutron detector.
Abstract: The charged hyperon beam at the CERN Super Proton Synchrotron (SPS) has been used to collect data on semileptonic decays of Σ−, Ξ−, and Λ. In this article we report results on the\(\sum \to ne\bar v\) decay mode. A magnetic channel selected 100 GeV/c (130 GeV/c) negatively charged particles produced in the forward direction by interaction of the 210 GeV/c (240 GeV/c) SPS proton beam on a BeO target. The Σ− hyperons were identified in a DISC Cerenkov counter, and the negatively charged decay particle was analysed by a magnetic spectrometer. The neutron direction was obtained from the Σ− decay vertex and from the impact point measured in a neutron detector. Electron-hadron discrimination was achieved by the combined use of lead-glass and transition radiation detectors. The\(\sum \to ne\bar v\) branching ratio measurement gave a value of (0.96±0.05) ×10−3. Measurements of the centre-of-mass distributions (baryon kinetic energy, electron-antineutrino correlation, and Dalitz plot distributions) yield the axial-vector to vector form factor ratio |g1/f1|=0.34 ±0.05. From the study of the electron momentum spectrum, the negative sign ofg1/f1, which is expected within the Cabibbo theory framework, is favoured by at least 2.6 standard deviations. The effects ofq2-dependence off1 andg1 and of radiative corrections, the measurement of the weak magnetism form factorf2, and the effect of possible second-class current terms are discussed. Results on the other Ξ−, Σ−, and Λ semileptonic decays are reported in separate articles.

Journal ArticleDOI
17 Mar 1983-Nature
TL;DR: It is shown that the membrane patches in rat kidney are selectively devoid of filipin-sterol complexes and that when identified in thin sections, they have a cytoplasmic bristle coat: both of these features are characteristics of coated pits which, in other systems, are involved in receptor-mediated endocytosis.
Abstract: The water permeability of collecting ducts is greatly increased by the antidiuretic hormone, vasopressin. This permeability increase is associated with the appearance of intramembrane particle (IMP) clusters on the luminal plasma membranes of principal cells of the collecting duct epithelium. IMP aggregates have also been related to an increase in water permeability of two other vasopressin-sensitive epithelia, the amphibian urinary bladder and the amphibian epidermis, and it has been proposed that these specialized membrane domains might represent specific water-permeable membrane patches, induced by the hormone in their respective epithelia. Using a cytochemical probe for membrane cholesterol, filipin, we show here that the membrane patches in rat kidney are selectively devoid of filipin-sterol complexes and that when identified in thin sections, they have a cytoplasmic bristle coat: both of these features are characteristics of coated pits which, in other systems, are involved in receptor-mediated endocytosis. We also show that vasopressin induces the appearance of coated pits on collecting duct luminal membranes in Brattleboro homozygous rats, which have hereditary diabetes insipidus.

Journal ArticleDOI
C. Rossel1
TL;DR: In this article, a summary of the recent superconducting systems is presented followed by a more extensive discussion on the relationships between structural parameters and super-conducting properties of the two largest families, i.e., the ternary molybdenum chalcogenides (Chevrel phases) and the Ternary rhodium borides.
Abstract: Within the past decade an enormous increase of interest has occurred in the field of ternary superconductors, the number of which is growing rapidly due to the extraordinary flexibility Nature offers in combining three elements. A summary of the recent superconducting systems is presented followed by a more extensive discussion on the relationships between structural parameters and superconducting properties of the two largest families,i.e. the ternary molybdenum chalcogenides (Chevrel phases) and the ternary rhodium borides.

Journal ArticleDOI
TL;DR: It is demonstrated that exogenous melatonin can inhibit or delay sexual maturation in the male rat if administered between 20 and 40 days of age and suggested that this inhibitory action is exerted at the hypothalamic and/or pituitary level.
Abstract: The influence of daily sc administration of melatonin (5–100 μg/day) on sexual development of prepubertal and pubertal male rats was studied in vivo. Adult animals were also studied. When melatonin was injected daily into young animals starting at day 20 of age, dose-dependent reductions in plasma testosterone, testis and seminal vesicles weights, plasma FSH and LH levels, and pituitary GnRH receptor number were observed at day 40 or 45 of age when animals were killed. In contrast, prepubertal animals (5–20 days old) showed no significant responses to similar treatment with melatonin, whereas in adult animals (70–90 days old), melatonin elicited only a small decrease in plasma testosterone concentration. Melatonin analogs such as AT-acetyl-serotonin and 5-hydroxytryptophol administered daily from 20–45 days of age did not produce any effect. Chronic melatonin administration from 20–50 days of life did not alter the occurrence of the nocturnal rise of circulating plasma melatonin, but did enhance its ampli...

Book ChapterDOI
01 Jan 1983
TL;DR: In this article, a review of complexes in which a dioxygen ligand is bonded to a transition metal is presented, and three aspects of these complexes are discussed in detail: the structure, the electronic structure, and the reactivity.
Abstract: This article gives a review of complexes in which a dioxygen ligand is bonded to a transition metal. Three aspects of these complexes are discussed in detail: the structure, the electronic structure, and the reactivity. The structural section summarises the recent X-ray crystal structure determinations, and the structural data obtained by other methods. The electronic structure is first considered in qualitative terms which allow the rationalisation of the different structures observed, and this qualitative model is compared with the results of calculations and with spectroscopic data. The reactivity of the complexes is discussed separately for each structural class in terms of the electronic structure. An attempt is made to compare the results obtained in historically different areas of research. Our objective is to give a clear summary of current knowledge of these compounds for workers interested in their application to catalysis and in their role in biochemical systems.

Journal ArticleDOI
TL;DR: Results indicate that expression of the TOL plasmid-encoded catabolic pathway is regulated by at least three control elements, two of which interact in the induction of the lower pathway by methylated hydrocarbons and alcohols and one of which responds only to nonmethylated substrates.
Abstract: Mutant derivatives of the TOL plasmid pWW0-161, containing Tn5 insertions in the xylS and xylR regulatory genes of the catabolic pathway, have been identified and characterized. The two genes are located together on a 1.5- to 3.0-kilobase segment of TOL, just downstream of genes of the enzymes of the meta-cleavage pathway. As predicted by a current model for regulation of the TOL catabolic pathway, benzyl alcohol dehydrogenase, a representative enzyme of the upper (hydrocarbon leads to carboxylic acid) pathway, was induced by m-methylbenzyl alcohol in xylS mutant bacteria but not in a xylR mutant, whereas catechol 2,3-oxygenase, a representative enzyme of the lower (meta-cleavage) pathway, was induced by m-toluate in a xylR mutant but not in the xylS mutants. Unexpectedly, however, catechol 2,3-oxygenase was not induced by m-methylbenzyl alcohol in xylS mutants but was induced by benzyl alcohol and benzoate. These results indicate that expression of the TOL plasmid-encoded catabolic pathway is regulated by at least three control elements, two of which (the products of the xylS and xylR genes) interact in the induction of the lower pathway by methylated hydrocarbons and alcohols and one of which responds only to nonmethylated substrates.

Journal ArticleDOI
TL;DR: In this paper, a comprehensive formal system is developed that amalgamates the operational and the realistic approaches to quantum mechanics, and a sharp distinction is made between events, operational propositions, and the properties of physical systems.
Abstract: A comprehensive formal system is developed that amalgamates the operational and the realistic approaches to quantum mechanics. In this formalism, for example, a sharp distinction is made between events, operational propositions, and the properties of physical systems.

Journal ArticleDOI
TL;DR: A simple method is described to embed material in resin, in the form of microscope slides, to observe it with high resolution light microscopy, to select, orient and section it for TEM.
Abstract: SUMMARY A simple method is described to embed material in resin, in the form of microscope slides, to observe it with high resolution light microscopy, to select, orient and section it for TEM. This method can be applied to many kinds of material but is particularly useful for the study of rare or tiny plant or animal microorganisms from field or culture. A diamond scriber, translucent hydrosoluble resin release agent, translucent and smooth resin stubs and a longitudinally perforated block-holder for ultramicrotome are the specific tools of this method.

Journal ArticleDOI
TL;DR: The depletion of substance P immunoreactivity from nerves in arteries and veins by capsaicin suggests that substance P-containing vascular nerves are primarily sensory in nature.
Abstract: Substance P-immunoreactive nerve fibres were localized by the indirect immunohistochemical method in the adventitia and the adventitial-medial border of large peripheral arteries and veins of the rat. Arteries showed a richer substance P-containing innervation than veins. The superior mesenteric artery was densely innervated, whereas no substance P-containing fibres were found around the carotid artery. Substance P produced a vasoconstriction of the veins, but was basically without effect on arteries, although with the carotid artery a dose-dependent relaxation was observed. The absence of a correlation between the degree of innervation of the blood vessels and their responsiveness to exogenous substance P suggests that these nerves do not subserve a vasomotor function. The depletion of substance P immunoreactivity from nerves in arteries and veins by capsaicin suggests that substance P-containing vascular nerves are primarily sensory in nature.

Journal ArticleDOI
TL;DR: The nucleotide sequence of 1100bp around the origin of replication of the pSC101 plasmid has been determined and includes the sequence of the par region involved in partitioning of plasmids at cell division.
Abstract: The nucleotide sequence of 1100bp around the origin of replication of the pSC101 plasmid has been determined. This segment of DNA is capable of replication in the presence of a helper plasmid. The sequence data reveal similarities between pSC101 and several other replicons. The origin of replication contains three direct repeats of an 18bp sequence associated with a segment exceptionally rich in A-T base pairs. A promotor that probably directs transcription of a gene encoding an essential plasmid replication function is associated with a region of extensive potential secondary structure. The sequence presented here includes the sequence of the par region involved in partitioning of plasmids at cell division.