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  • 1
    Electronic Resource
    Electronic Resource
    Coordinatively unsaturated complexes [Fe2(CO)5(.mu.-P-tert-Bu2)(.mu.-PR2)](Fe:Fe) (R = Cy, Ph): addition of PBu3, Ph2PH, and dppm (dppm = bis(diphenylphosphino)methane). The unprecedented complex [Fe2(CO)3(.mu.-P-tert-Bu2)(.mu.-PCy2)(.mu.-dppm)](Fe-Fe) (1994)
    s.l. : American Chemical Society
    Organometallics 13 (1994), S. 172-178 
    Details
    ISSN: 1520-6041
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/om00013a028
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  • 2
    Electronic Resource
    Electronic Resource
    Guo, Jiann-Jong: Price Reform in China, 1979–86 : Basingstoke, St Martin's Press, 1992 (1994)
    Cambridge : Cambridge University Press
    The @China quarterly 138 (1994), S. 528-530 
    Details
    ISSN: 0305-7410
    Source: Cambridge Journals Digital Archives
    Topics: Linguistics and Literary Studies , History , Political Science , Sociology , Economics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1017/S0305741000035955
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  • 3
    Electronic Resource
    Electronic Resource
    Quantitative determination of chloride by means of flow injection analysis with spectrophotometric detection in the UV/VIS range (1994)
    Springer
    Microchimica acta 116 (1994), S. 183-189 
    Details
    ISSN: 1436-5073
    Keywords: chloride determination ; flow injection analysis ; mercury ; thiocyanate ; chloranilate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Chloride is determined indirectly by Spectrophotometric flow injection analysis. Two systems are compared, both based on the principle of ion exchange of easily detectable anions versus chloride from suitable mercury salts. The first method is based on the exchange of chloride with chloranilate which is detected at 332 nm or at 306 nm in neutral or in acidic medium respectively. In the second case, chloride reacts with Hg(SCN)2. The liberated thiocyanate forms a strongly coloured complex with Fe(III) in acidic solution with an absorption maximum at 460 nm. Both methods have a detection limit of about 5 μmol Cl−/l (175 ng/ml). In the case of the thiocyanate method, the relative standard deviation is about 2% (7 measurements) in the range of 5 to 150 μmol/l and decreases significantly to a value of approximately 0.2% at higher concentrations; for the chloranilate method it is 10% for lower and about 1% for higher concentrations respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01260363
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of citric acid by means of competitive complex formation in a flow injection system (1994)
    Springer
    Microchimica acta 113 (1994), S. 203-210 
    Details
    ISSN: 1436-5073
    Keywords: citric acid ; flow injection analysis ; spectrophotometry ; complex formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A photometric method for the determination of citrate and other organic acids based on their ability to complex Fe3+-ions is presented. The red colored complex of [Fe(SCN)2]+, used as reagent, is destroyed upon contact with the sample because the organic acid complexes the Fe3+-ion. The decrease in absorption is monitored at 460 nm. The reaction is carried out in a simple flow injection system either in single or preferably double channel configuration. The influence of pH was investigated. Best results were obtained by adjusting the carrier stream to pH 2.0–2.5 with a KCl/HCl-buffer. With an increasing concentration of reagent the linear range is shifted to higher citrate concentrations. The slope of the calibration graph and the linear range are influenced by the sample volume. Other variations of parameters include flow rate, reactor volume and diameter of tubing. Generally speaking, optimum conditions for the flow system are not specified because they vary with the application. The typical conditions for a calibration graph from 1 to 8 mmol/l citrate were a reagent concentration of 2.6 mmol/l [Fe(SCN)2]+, a flow rate of 2.4 ml/ min, a reactor length of 50 cm with tubing of 0.97 mm inner diameter and a sample volume of 100 μl. At these system settings the coefficients of variation were 2.5% and 1.6% for eight replicate measurements of samples containing 4 mmol/l and 8 mmol/l citrate, respectively. Up to 180 samples can be analyzed per hour. Naturally the method is disturbed by all other ions that form complexes or precipitates with Fe3+-ions. Therefore its application is limited to samples with a known matrix, which was given in the analysis of citrate in lemon flavored soft drinks, where the citric acid usually accounts for 95 to 99% of the total acidity and other interfering ions are absent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01243611
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  • 5
    Electronic Resource
    Electronic Resource
    Hand radiographs: a comparative study of digital luminescent radiography (DLR) and conventional screen-film system combinations (1994)
    Springer
    European radiology 4 (1994), S. 225-230 
    Details
    ISSN: 1432-1084
    Keywords: Digital luminescent radiography (DLR) ; X-ray intensifying screens ; Radiographic image enhancement ; Hand radiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A total of 102 matched hand radiographs were taken by digital luminescent radiography (DLR) and conventional) screen film system combinations. In DLR two differently postprocessed images were obtained from each data set: A display with low-spatial frequency enhancement filtered to took like a conventional radiograph was placed opposite a display with high-edge enhancement. Conventional and digital images were evaluated rank only and separately by four radiologists, using a questionnaire. Using DLR proved diagnostically equivalent to the conventional technique except for a diminished visibility of subtle erosions and fissures. High-frequency enhancement did not provide additional diagnostic information and led to artifacts at the edges of metal prostheses. Densitometry confirmed an optimized density of digital radiographs. The main argument for the employment of digital techniques is the availability of data for picture archiving and communications systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00606452
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  • 6
    Electronic Resource
    Electronic Resource
    Pulmonary uptake of bupivacaine in isolated perfused rat lung (1994)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 351 (1994), S. 99-106 
    Details
    ISSN: 1432-1912
    Keywords: Key words Lung perfusion ; Bupivacaine ; Fluorochrome-labeled capillaries ; First-pass retention ; Inulin ; Tritium-labeled water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ability of rat lung to remove the local anaesthetic drug bupivacaine from the blood was studied in isolated organs which were perfused either in an open (single-pass mode) or in a closed system (recirculating medium). Isolated perfused rat lungs exhibited a very low capacity to metabolize bupivacaine within 3 h during which the drug circulated continuously through the organ. The clearance values differed only by 0.2 ml/min from the control parameters in sham perfusions. The calculated extraction ratio was 0.2% and the elimination half-life was about 210 min. The volume of distribution of bupivacaine was 133 ml which remarkably surmounted the reference values obtained for sham perfusions. The distribution of bupivacaine into the pulmonary tissue was investigated applying the multiple indicator dilution technique to isolated lungs perfused in the single-pass mode. The mean elimination time of model compounds for distribution into the intravascular space, 14C-inulin, and the total water space, 3H-water, were 68 and 75 s at a flow rate of 6 ml/min. The volume of distribution was 5.9 ml for inulin and 6.5 ml for water. The mean transit time for concomitantly injected bupivacaine was 221 s and the volume of distribution was 14.4 ml. The respective parameters of sham perfusions performed without an isolated organ were substantially lower, i.e. mean elimination time 50, 50 and 61 s and distribution volume 4.9, 5.0 and 6.1 ml for inulin, water and bupivacaine. The volume of distribution during single-pass contact of bupivacaine to lung was not substantially influenced by an increase of the flow rate from 6 to 9 and 12 ml/min whereas the mean transit time dropped from 221 to 121 and 108 s, respectively. These results support the assumption that bupivacaine is extensively retained by the pulmonary tissue and that elimination of bupivacaine by metabolism can be neglegted for lung. The hemodynamic parameters of bronchiolar perfusion in the artificially perfused lung were determined using two fluorochrome-labeled macromolecular proteins, i.e. fluorescein-isothiocyanate (FITC)- and lissamine-rhodamine-B 200 (RB 200)-labeled globulin. After 10 min of perfusion at a flow rate of 12 ml/min in the closed system an area of 10.8% of the peribronchiolar tissue area contained the dye-label FITC. A very similar index (10.1%) of dye-coloured capillaries was obtained when the lungs of anaesthetized rats were examined 10 min after intravenous injection of the fluorochrome into the pulmonary artery in vivo. In isolated perfused rat lungs receiving both FITC and RB 200 59.5% of FITC-labeled capillaries were reached by the second fluorochrome within 2 s. This fraction accounted for 93.3% after 10 s of circulation time. This proves that isolated rat lungs were well perfused in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169070
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  • 7
    Electronic Resource
    Electronic Resource
    Fine structure and critical modes at the first-order Suhl instability in YIG spheres (1994)
    Springer
    The European physical journal 95 (1994), S. 55-62 
    Details
    ISSN: 1434-6036
    Keywords: 75.30D ; 76.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The FMR fine structure of the first-order Suhl instability in YIG spheres, previously observed by Jantz and Schneider (1975), has been re-investigated both for the conditions of coincidence and subsidiary absorption (3 and 9 GHz) from room temperature down to 1.6K. The observed fine structure consists of several series of closely spaced resonances, indicating a critical wave vectork≠0 even for half the pumping frequency lower than the 45° spin-wave branch, which is in contrast to the prediction of Suhl's theory. The spacing of these resonances was analyzed in terms of spherical modes. We were able to determine the indices and the effective wave numbers (≈105 cm−1) of the critical modes. The very different dynamic behaviour observed at room temperature and at 1.6K can be attributed to a competition of different damping mechanisms—mainly surface pit scattering and three-magnon confluence processes — and their dependences on field, frequency, and temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01316843
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  • 8
    Electronic Resource
    Electronic Resource
    Sequestration of host-plant-derived flavonoids by lycaenid butterflyPolyommatus icarus (1994)
    Springer
    Journal of chemical ecology 20 (1994), S. 2523-2538 
    Details
    ISSN: 1573-1561
    Keywords: Polyommatus icarus ; Lepidoptera ; Lycaenidae ; Coronilla varia ; Medicago sativa ; Fabaceae ; flavonoids ; sequestration ; plant-insect interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Larvae of the lycaenid butterflyPolyommatus icarus were reared on inflorescences ofCoronilla varia andMedicago sativa, which are rich in flavonoids. Twelve different flavonoids (five compounds from the former and nine from the latter), including aglycones andO-glycosides of kaempferol, quercetin, and myricetin were isolated and identified by spectroscopic means. NMR and MS data for the new acylated glycoside kaempferol 3-O-6″-(3-hydroxy-3-methylglutaroyl)-β-d-glucopyranoside are reported. Comparative HPLC analysis of the respective host plants and of larvae, pupae, and imagines ofP. icarus indicated selective uptake and accumulation of kaempferol vs. quercetin and myricetin derivatives. The latter were excreted largely unchanged through the feces. Irrespective of the larval host plant kaempferol 3-O-glucoside was found as the major flavonoid in larvae, pupae, and imagines ofP. icarus, accounting for approximately 83–92% of all soluble flavonoids in adult butterflies. Within the imagines, approximately 80% of all flavonoids are stored in the wings (especially in the orange submarginal lunules), whereas the remaining 20% reside in the bodies. Feeding experiments with artificial diet demonstrated that the insects are able to form kaempferol 3-O-glucoside by glucosylation of dietary kaempferol. Possible functions of the sequestered flavonoids, especially for mate recognition ofP. icarus, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02036189
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  • 9
    Electronic Resource
    Electronic Resource
    K-Opioid activity of the four stereoisomers of the peripherally selective κ-agonists, EMD 60 400 and emd 61 753This paper is dedicated to Prof. H.J. Langmann on the occasion of his 70th birthday. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 6 (1994), S. 685-689 
    Details
    ISSN: 0899-0042
    Keywords: chromatographic resolution of stereoisomers ; molecular modelling ; conformation ; κ-opiate receptor ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The four stereoisomers of the two peripherally selective κ-opioid agonists EMD 60 400 and EMD 61 753 were synthesized, tested for stereoisomeric purity, and examined for affinity to the κ opioid receptor. The relationships between the configuration of these molecules and their biological activity are discussed. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530060814
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  • 10
    Electronic Resource
    Electronic Resource
    Identification of transferrin as one of multiple EDTA-extractable extracellular proteins involved in early chick heart morphogenesis (1994)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 54 (1994), S. 207-218 
    Details
    ISSN: 0730-2312
    Keywords: EDTA soluble proteins ; chick embryo ; purification ; epithelial-mesenchymal interactions ; transferrin ; conalbumin ; extracellular matrix ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: It was demonstrated previously that a polyclonal antibody (ES1) raised against EDTA extractable proteins from embryonic chicken heart blocks cardiac endothelial-mesenchymal transformation in a culture bioassay and stains extracellular matrix at sites of embryonic inductive interactions, e.g., developing heart, limb buds, and neural crest forming region (Krug et al., 1987, Dev Biol 120:348-355; Mjaatvedt et al., 1991, Dev Biol 145:219-230). In the present study, by using an antiserum (ES3) to a similar immunogen, we affinity purified four major EDTA-soluble proteins. These proteins migrated as 27, 44, 63, and 70 kD molecules under reduced conditions and 27, 41, 52, and 59 kD under nonreduced conditions, respectively, on SDS-PAGE. Based on several criteria, the protein migrating at 70/59 kD (reduced/nonreduced) was indistinguishable from chicken transferrin (conalbumin): (1) amino acid sequencing showed that eight N-terminal residues were identical to those of chicken transferrin, (2) acid hydrolysates of both proteins had nearly identical compositions, (3) the protein co-migrated exactly with chicken transferrin under both reduced and nonreduced conditions, and (4) ES3 IgG recognized both the 70/59 kD protein and chicken transferrin by western blot analysis of nonreduced samples, but not with reduced samples. Immunohistochemistry of chicken embryonic heart with antibodies against transferrin demonstrated that anti-transferrin immunoreactivity is present in myocardium but absent in cardiac endothelium before the initiation of cardiac endothelial-mesenchymal formation. However, both cardiac endothelium and migrating mesenchymal cells became immunoreactive with anti-transferrin at the time transformation occurred. These findings suggest a possible involvement of transferrin in the inductive process of cardiac endothelial-mesenchymal transformation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240540209
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