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  • 1
    Electronic Resource
    Electronic Resource
    Serum concentrations of amiodarone during long term therapy. Relation to dose, efficacy and toxicity (1983)
    Springer
    European journal of clinical pharmacology 24 (1983), S. 485-494 
    Details
    ISSN: 1432-1041
    Keywords: amiodarone ; pharmacokinetics ; therapeutic serum level ; thyroid function ; antiarrhythmic therapy ; adverse effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In 17 patients on long term therapy with amiodarone, serum drug levels measured by HPLC were related to pharmacological effects. At steady state, serum levels were directly proportional to the dose, 5 mg/kg per day leading to an average serum level of approximately 2.5 µmol/l. The non-amiodarone level of iodine averaged 4-times higher than the level of amiodarone iodine. The elimination half-life of amiodarone ranged from 21 to 78 days, and of non-amiodarone iodine from 24 to 160 days. Control of arrhythmias was satisfactory in all 12 evaluable patients, when the serum amiodarone level exceeded 1.5 µmol/l. Deterioration of vision and polyserositis occurred only at amiodarone levels above 4 µmol/l. Tentatively, a therapeutic range of 1.5 to 4 µmol/l is proposed. In contrast, thyroid dysfunction was observed at any amiodarone level. In view of the narrow therapeutic window, therapy with amiodarone may be optimized by monitoring its serum level and in addition, thyroid function should be regularly checked.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609891
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  • 2
    Electronic Resource
    Electronic Resource
    Insertion and deletion mutations within the nif region of Rhizobium japonicum (1984)
    Springer
    Plant molecular biology 3 (1984), S. 159-168 
    Details
    ISSN: 1573-5028
    Keywords: electron microscopy ; mutants ; nitrogen fixation ; Rhizobium ; symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Insertion and deletion mutants were used to characterize a genomic region of Rhizobium japonicum where the nitrogenase structural genes are located on two separate operons nifDK and nifH. In addition to previously described nifD:: Tn5 and nifK:: Tn5 mutations we have now generated, by localized mutagenesis, further Tn5 insertion mutations in the vicinity of nifDK as well as within and adjacent to nifH. The nifD:: Tn5, nifK:: Tn5, and nifH:: Tn5 mutant strains were of the Nod+ Fix- phenotype whereas all other mutants were symbiotically fully effective (Nod+ Fix+). The nifH:: Tn5 mutation was helpful in the identification of the nifH gene product (the dinitrogenase reductase) by two-dimensional gel electrophoresis: due to its polar effect this insertion specifically abolished the synthesis of that protein under microaerobic culture conditions. The ultrastructure of soybean root nodules infected with either the nif + wild-type or with the nif - (but otherwise isogenic) mutant strains was analyzed by electron microscopy. All contained fully developed bacteroids, but the nitrogen non-fixing mutants showed massive accumulation of PHB. Of Tn5-containing strains, kanamycin sensitive derivatives were obtained which contained deletions. Several classes of deletion mutants were found which, as judged by their physical DNA structure and their phenotypes, allowed the following most important conclusions: (i) deletions lacking both the nifDK and nifH regions indicate linkage between the two operons whereby at least 15 kb of DNA separate them; (ii) one deletion ending upstream from nifH, and lacking only nifDK, indicates that the nifDK operon is located on the 5′-flanking side of the nifH operon; (iii) all deletion mutants are Nod+ indicating that there are no essential nodulation gnes located between and adjacent to nifDK and nifH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00016063
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  • 3
    Electronic Resource
    Electronic Resource
    Mathematical model of the single-fibre action potential (1984)
    Springer
    Medical & biological engineering & computing 22 (1984), S. 433-439 
    Details
    ISSN: 1741-0444
    Keywords: Action potentials ; Electromyography ; Mathematical model ; Single fibre
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A methematical model of the single-fibre extra- and intracellular action potential is proposed whereby the transition from one to the other is given by an approximate analytical relationship. The model is given in both the time and the frequency domain, and has a simple mathematical form. Based on the new model an analytical description of the transfer function of the muscle tissue is given. The proposed model compares favourably with previously published models and experimental results. The model allows a simple interpretation of the involved influence of the length and asymmetry of the transmembrane potential on the extracellular potential field. The proposed model should be helpful in the electrical modelling and simulation of neuromuscular activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02447703
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  • 4
    Electronic Resource
    Electronic Resource
    Detailed investigation of the “DIP” structure in the μ+-relaxation rate in Nb (1984)
    Springer
    Hyperfine interactions 17 (1984), S. 177-182 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The depolarization rate of positive muons implanted in a number of nominally pure, cylindrical Nb single crystals (maximal 250 ppm Ta, 100 ppm N + O) was investigated at two temperatures, viz. 14.0 and 36.8 K, in a high transverse field of 7.5 kG with the stroboscopicμSR technique in order to study the nature of the “dip” at 22 K. To determine the sites at which the muon is trapped on both sides of this dip, the full angular dependence of the depolarization rate was measured by rotating a large single crystal around its 〈110〉 cylinder axis in a transverse magnetic field. The resulting curves for both temperatures are quite different, reflecting clearly the different environment in which the muon is trapped above and below 22 K. The trapping site at 36.8 K was identified to be of tetrahedral symmetry, located near a Ta substitutional impurity and possibly associated with an interstitial impurity. Lattice distortions due to these impurities and radial relaxation around the muon,δR/R, were determined. The latter is +6.7(6)% for nearest neighbors and −6(2)% for next nearest neighbors. The 14.0 K angular dependence could not be fitted by considering distorted tetrahedral and octahedral sites and pointlike muons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02065899
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  • 5
    Electronic Resource
    Electronic Resource
    Positive muons in antimony bismuth alloys (1984)
    Springer
    Hyperfine interactions 17 (1984), S. 387-391 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract StroboscopicμSR and TD-μSR techniques were used to measure theμ + Knight shiftK μ, and relaxation rateλ inSbBi alloys as functions of magnetic fieldH, temperatureT, the angleθ betweenH and the crystallineĉ axis, and the concentration [Bi] of alloyed Bi. In pure Sb and inSbBi (6.5%),K μ (θ=0) andK μ (θ=π/2) both decrease linearly withT up to about 100 K, but bothK μ and its anisotropy are smaller in the 6.5% alloy, indicating a “dilution” effect. With 15 at % Bi,K μ is reduced further but itsT-dependence and that ofλ are dramatically altered. At low temperaturesK μ (θ=0) inSbBi(15%) actually becomes negative and the sign of the anisotropy is reversed. In the same sample,λ is proportional toH at both 20 K and 150 K; at 120 Kλ is proportional toK μ ifθ is used as an implicit variable, but at 36 K this is not the case. A consistent phenomenological description is offered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02065931
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  • 6
    Electronic Resource
    Electronic Resource
    Possibility of a Lifshitz phase transition in Cd observed by a singularity in the muon Knight shift (1984)
    Springer
    Hyperfine interactions 17 (1984), S. 359-363 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract During the past much effort has been devoted to a systematic study of the muon Knight shiftK μ in metallic environments and its implications on the local electronic structure of hydrogen in metals [1]. These measurements in simple metals were essentially all carried out in polycrystalline samples at room temperature. The present measurements in Cd in polycrystalline and single crystal samples cover a temperature range between 20 K and the melting point of this strongly anisotropic metal (hcp crystal structure,c/a ratio 1.89 — idealc/a ratio 1.63). These measurements add qualitatively new and interesting aspects and insights on the screening of a light hydrogen isotope in a metal as well as on certain properties of the host material itself. The outstanding features of the muon Knight shift in Cd are: (i) a strong intrinsic temperature dependence with an increase ofK μ of more than 100% between 20 K and the melting point (T=593 K), (ii) an anomaly at 110 K in the form of a singularity in the isotropic part ofK μ which is interpreted as a band structure effect, (iii) an anisotropic Knight shift contribution fitting the expressionK(T,θ)=K iso(T)+K ax(T) * (3 · cos2 θ−1)/2, where both, the isotropic and the axial contribution ofK μ, are strongly temperature dependent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02065926
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  • 7
    Electronic Resource
    Electronic Resource
    Structural analysis using the input-output model: With special reference to networks of science (1984)
    Springer
    Scientometrics 6 (1984), S. 401-423 
    Details
    ISSN: 1588-2861
    Source: Springer Online Journal Archives 1860-2000
    Topics: Information Science and Librarianship , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract Social science network analysis originated in the small group sociometric tradition, thus many of the common assumptions of network models are inappropriate theoretically and formally for the analysis of open systems of social relationships. Five common assumptions of network analysis are identified, discussed and criticized: (a) generators are homogeneous, (b) relationships are dichotomous, (c) groups have fixed boundaries, (d) relationships are symmetric, and (e) networks are static. It is suggested that an open input-output model overcomes many of the difficulties inherent in the more common network analytical techniques. After a formal treatment of input-output analysis, and its relationship to network analysis, some interpretations from exchange theory are suggested. This model helps the analyst overcome many of the theoretical difficulties encountered in other models and allows the researcher to specify how subsets of individuals are “embedded” within larger social contexts. Specifically, because society is comprised of numerous interacting subsystems, this model is particularly beneficial in describing how groups of scientists interface with each other and with the larger social domains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02025828
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  • 8
    Electronic Resource
    Electronic Resource
    Muon Knight shift at a structural defect in zinc crystals (1984)
    Springer
    Hyperfine interactions 17 (1984), S. 365-369 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The interaction of a light hydrogen isotope with a structural defect is traced for the first time by means of the temperature dependence of the muon Knight shiftK μ in the hcp metal Zn. A surprising result is the huge and negativeK μ (−520 ppm) at the defect site, probably a multivacancy cluster.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02065927
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  • 9
    Electronic Resource
    Electronic Resource
    Muon Knight shift in platinum and in β-PdHx (x=0.70, 0.75) (1984)
    Springer
    Hyperfine interactions 17 (1984), S. 377-382 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Theμ + Knight shift in platinum has been measured between 20 K and 785 K. It shows a strong temperature dependence and scales with the magnetic bulk susceptibility. A temperature independent contribution of +40 to +60 ppm and a d-electron induced hyperfine field per unpaired d-electron per atom ofB hf,d Ω=−5.03 kG (±8.5%) are obtained. Theμ + Knight shift in PdH0.70 and PdH0.75 shows no dependence on temperature between 20 K andRT and increases fromK μ ppm forx=0.70 toK μ ppm forx=0.75, in good agreement with proton Knight shift measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02065929
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  • 10
    Electronic Resource
    Electronic Resource
    Positive muon Knight shift in graphite and Grafoil (1984)
    Springer
    Hyperfine interactions 17 (1984), S. 383-385 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Positive muon Knight shifts and relaxation rates were measured at room temperature in a graphite crystal and in a stack of Grafoil sheets. The Knight shift was ≈ 500 ppm in the single crystal and reduced by 0.702 in Grafoil. Both have the same (large) fractional anisotropy relative to theĉ axis or to the normal to the Grafoil sheets, respectively. The (isotropic) relaxation rates were 0.024(4)μs−1 in the crystal and 0.194(6)μ −1 in the Grafoil. Apparently theμ + in Grafoil “sees” highly aligned bulk crystalline graphite, and does not reach the surfaces of the sheets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02065930
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