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  • 1
    Electronic Resource
    Electronic Resource
    GaAs multiple quantum well microresonator modulators grown on silicon substrates (1992)
    Springer
    Optical and quantum electronics 24 (1992), S. S177 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract We report new results on the modulation characteristics of GaAs/AlGaAs asymmetric Fabry-Perot modulators grown on silicon substrates. We discuss factors affecting device performance and evaluate these by growing p-i-n quantum well diodes, and multilayer reflector stacks on silicon. Using data from these test structures we have designed an asymmetric microresonator modulator and achieve, experimentally, a 40% reflection change with only 5 V and a contrast ratio of 7.4 dB, also with 5 V.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00625823
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  • 2
    Electronic Resource
    Electronic Resource
    Ratio correlations and major element mobility in altered basalts and komatiites (1986)
    Springer
    Contributions to mineralogy and petrology 93 (1986), S. 89-97 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Attempts have been made in the recent literature to constrain major element mobility in altered basalts and komatiites using the molecular proportion ratio (MPR) diagrams developed by T.H. Pearce (1970). The method involves ratioing the molecular proportions of two oxides against a third oxide and presenting the results as an oxide-oxide ratio plot. The transformation appears to ‘clean up’ scatter plots with low correlations and produces highly correlated ratio plots. These plots have been taken to be indicative of igneous fractionation trends and thus of minimal bulk chemical change during alteration. There are however inherent statistical problems in ratio correlation which have received much attention in the mathematical literature. This paper explains the implications of enhanced correlations for work on altered rocks using ratio plots and suggests that extreme caution must be exercised in the interpretation of MPR diagrams.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00963587
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  • 3
    Electronic Resource
    Electronic Resource
    Ratio correlations and major element mobility in altered basalts and komatiites — reply to K.J. Vines (1987)
    Springer
    Contributions to mineralogy and petrology 97 (1987), S. 527-528 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00375330
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  • 4
    Electronic Resource
    Electronic Resource
    A fixed receiver for recording multichannel wide-angle seismic data on the seabed (1990)
    Springer
    Marine geophysical researches 12 (1990), S. 49-57 
    Details
    ISSN: 1573-0581
    Keywords: seismic refraction ; lithosphere ; continental shelf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Previous experiments to record seismic data at wide angle on the continental shelf have generally been unsuccessful in determining velocity structure in the lower crust; either the lines were too short or shot-receiver density too sparse to identify lower crustal arrivals. In contrast, deep normal incidence profiles show good structural resolution in the crust and uppermost mantle. A sea-bottom multichannel instrument has been developed to record datasets containing closely spaced traces, in order to improve the resolution of reversed wide-angle experiments on the continental shelf. The Pull-up Multichannel Array (PUMA) is a 1200 m, 12-channel hydrophone array for remotely recording seismic data on the seabed. It consists of 12 short hydrophone sections linked by 100 m-long passive sections. A pressure case is attached to the array at one end, in which recording electronics, cassette tape recorders and a battery power supply are housed. The PUMA is designed for deployment in water depths less than 200 m from a research ship and is moored to buoys for recovery. The instrument, which was successfully used in an experiment west of Lewis, Outer Hebrides, UK (Powell and Sinha, 1987) was specifically designed to provide a reliable determination of the velocity structure of the crust and uppermost mantle over part of the BIRPS WINCH deep normal incidence profile. Because the traces are closely spaced it is easy to correlate phases across the record section and to monitor changes in amplitude. A velocity structure for the continental crust and uppermost mantle has been devised from these data, using amplitude modelling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310562
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  • 5
    Electronic Resource
    Electronic Resource
    The use of a Quantimet image analysis system to analyse trypsin banding patterns of V79/4 (AH1) Chinese hamster chromosomes (1980)
    Springer
    Cellular and molecular life sciences 36 (1980), S. 1354-1356 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A Quantimet image-analysis system was programmed to identify and print out banding patterns from G-banded chromosome spreads of a clone derived from the established cell line V79/4 (Chinese hamster fibroblasts), designated V79/4(AH1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01960094
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  • 6
    Electronic Resource
    Electronic Resource
    Receptors for intercellular messenger molecules in microbes: Similarities to vertebrate receptors and possible implications for diseases in man (1986)
    Springer
    Cellular and molecular life sciences 42 (1986), S. 782-788 
    Details
    ISSN: 1420-9071
    Keywords: Evolution ; receptors ; plant hormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01941525
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  • 7
    Electronic Resource
    Electronic Resource
    Characteristics of plasma protein binding of tacrine hydrochloride: a new drug for Alzheimer's disease (1994)
    Springer
    European journal of clinical pharmacology 47 (1994), S. 151-155 
    Details
    ISSN: 1432-1041
    Keywords: Tacrine hydrochloride ; Alzheimer's disease ; plasma protein binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The aim of this study was to characterise the plasma protein binding of tacrine hydrochloride (THA) in vitro. Binding was assessed in the plasma of 11 healthy individuals aged 20 to 27 years using ultrafiltration followed by HPLC assay. At THA concentrations from 10 to 100 ng/ml protein binding ranged from 78.6 to 71.0%. Binding to commercially available human albumin ranged from 41.7 to 38.3% and to human α1-acid glycoprotein from 23.1 to 12.4% over the THA concentrations from 25 to 100 ng/ml. THA binding and total plasma protein, plasma albumin and α1-acid glycoprotein were measured in healthy young subjects (n=13), healthy elderly individuals (n=12) and patients hospitalised with acute illnesses (n=8). There were significant differences between the groups in total plasma protein, plasma albumin and in α1-acid glycoprotein but no differences in the protein binding of THA which remained constant at about 75%. There was no correlation between THA binding and any plasma protein concentration. The THA binding was not high enough to be of major significance clinically or to reduce the validity of total plasma THA measurement in therapeutic monitoring.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194965
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  • 8
    Electronic Resource
    Electronic Resource
    Variability in the plasma protein binding of velnacrine (1-hydroxy tacrine hydrochloride) A potential agent for Alzheimer’s disease (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 115-119 
    Details
    ISSN: 1432-1041
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract. Objectives: To quantify the protein binding of velnacrine in healthy individuals and investigate potential sources of variability. Setting: Medical School Unit, Southmead Hospital, Bristol. Subjects: Plasma samples were obtained from the following groups: a) 11 healthy volunteers aged 18 to 30 years; b) 10 healthy volunteers aged 73 to 87 years; c) 10 patients aged 65 to 85 years hospitalised for a variety of acute illnesses. Methods: Aliquots of plasma from the above subjects were incubated with various concentrations of velnacrine, in the presence and absence of tacrine hydrochloride. Standard solutions of human serum albumin and α1 acid glycoprotein were incubated with velnacrine. The degree of protein binding was determined using the Amicon centrifree micropartition system. Results:Over the range of concentrations from 10 to 320 ng ⋅ml−1, there was a decrease in protein binding from 59.1 to 46.7%. 2) At 40 ng⋅ml−1 the plasma protein binding of velnacrine was 54.8% in the group a subjects, 51.9% in the group b subjects and 53.0% in the group c subjects (NS). 3) The mean total plasma protein concentration was significantly lower in the samples from elderly subjects. The mean albumin and α1 acid glycoprotein concentrations were lower and higher respectively in patients with acute disease. 4) Velnacrine was shown to bind to both albumin and α1-acid glycoprotein, but together they did not account for total binding. 5) The binding of velnacrine was significantly decreased from 59.3 to 43.9% in the presence of a therapeutic concentration (25 ng ⋅ml−1) of THA. There was no evidence that velnacrine displaced THA. Conclusion: Protein binding can be discounted as a major source of variation in the relationship between drug concentration and effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050078
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  • 9
    Electronic Resource
    Electronic Resource
    Assessment of the value of therapeutic monitoring of tacrine in Alzheimer's disease (1998)
    Springer
    European journal of clinical pharmacology 54 (1998), S. 721-724 
    Details
    ISSN: 1432-1041
    Keywords: Key words Alzheimer's disease ; Tacrine ; Therapeutic monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objectives: The purpose of this study was to validate the lower end of the putative therapeutic range of serum tacrine concentrations of 7–20 ng · ml−1 in the treatment of Alzheimer's disease. Methods: The relationship between dose, steady-state serum tacrine concentrations and change in MMSE score (a measure of cognitive function) was examined in 106 Alzheimer's disease patients who had been treated with the drug for 12 weeks. Results: In all, 72% of patients showed some response, but there was no relationship between dose and the chance of a favourable outcome. The proportion of patients with serum concentrations above 7 ng · ml−1 who improved (79%) was significantly greater than that of those with serum concentrations below this level (47%) (P 〈 0.02). Also, a significantly greater proportion of patients with serum concentrations above both 5 ng · ml−1 and 9 ng · ml−1 showed improvement in comparison to those with concentrations below these levels. Conclusions: This study indicates that therapeutic monitoring of serum tacrine concentrations might increase the possibility of responding to tacrine by some 68%. This represents an important contribution to the management of Alzheimer's disease patients with this drug, and may also be relevant to the use of the newer generation of cholinesterase inhibitors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050541
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  • 10
    Electronic Resource
    Electronic Resource
    Hol Chan: Demonstrating that marine reserves can be remarkably effective (1994)
    Springer
    Coral reefs 13 (1994), S. 90-90 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300766
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