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  • 1
    Electronic Resource
    Electronic Resource
    Enzymes in stereoselective pharmacokinetics of endogenous substancesPresented at the Second International Symposium on Chiral Discrimination, May 27-31, 1991, Rome, Italy. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 247-251 
    Details
    ISSN: 0899-0042
    Keywords: radioenzyme assay ; stereospecific assay ; carnitine acetyl transferase ; L-carnitine family ; L-carnitine ; acetyl-L-carnitine ; propionyl-L-carnitine ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of enzymes to assay individual components of the L-carnitine family in pharmaceuticals, foodstuffs, and biological fluids with various forms of detection is reviewed. The most useful enzyme in the assay of compounds of the L-carnitine family is carnitine acetyl transferase (CAT), which catalyses the reversible interconversion of L-carnitine and its short-chain acyl esters. CAT can be used in one or more coupled reactions combined with U.V., or radiolabelled detection, or combined with HPLC, allowing, enantioselective, structurally specific, and, in the case of radiolabelled tracing, highly sensitive assays to be carried out. When compared with chromatographic separation of enantiomers or diastereoisomers, enantioselective enzyme mediated assays may be cheaper, more sensitive, and simpler, but they do not allow the nonpreferred isomer to be assayed. Consequently, they are appropriate for the specific assay of endogenous enantiomeric substrates of the enzyme concerned, in biological samples. The analysis of the other enantiomer in raw materials or in pharmaceuticals must be more properly approached by enantioselective chromatographic methods.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040408
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of nanophase powders prepared by laser synthesis (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 22 (1994), S. 248-253 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Si—based (Si—C—N and Si—C—Al) nanopowders prepared by laser synthesis process have been studied by XPS and XAES analyses.The changes of the silicon coordination as a function of the carbon fraction in Si—C—N powders have been investigated by a detailed analysis of Si 2p and Si KLL lines and the measurements of the Auger parameter Ek(Si KLL) + Eb(Si 2p). The non-linear dependence of the Auger parameter on the carbon fraction has been interpreted as due to the formation of a carbonitride nanophase, indicating that the ternary powders are not merely a mixture of silicon carbide and silicon nitride.In Si—C—Al powders it has been found that the incorporation of aluminium results in a modified structure of the silicon carbide, as shown by the variation of the different spectral features.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740220154
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  • 3
    Electronic Resource
    Electronic Resource
    On the association of DNA primase activity with the nuclear matrix in HeLa S3 cells (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 11 (1993), S. 287-290 
    Details
    ISSN: 0263-6484
    Keywords: DNA primase ; nuclear matrix ; nuclear isolation ; heat exposure ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have reinvestigated the association of DNA primase activity with the nuclear matrix prepared from exponentially growing HeLa S3 cells. We have found that 25-30 per cent of the nuclear primase activity resists extraction with 2 M NaCl and digestion with Dnase I. Unlike previous investigations, done with the same cell line, the results showed that nuclear matrix-bound DNA primase activity represented less than 10 per cent of the total cell activity. Association of high levels of primase activity with the nuclear matrix was strictly dependent on a 37°C incubation of isolated nuclei prior to subfractionation. Evidence was obtained that the method used for preparing nuclei can have a dramatic effect on the amount of primase activity which is recovered both in the postnuclear supernatant and in isolated nuclei, thus seriously affecting the interpretation of the results about the quantity of DNA primase activity bound to the nuclear matrix.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cbf.290110410
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  • 4
    Electronic Resource
    Electronic Resource
    No discrete complexes containing DNA polymerase α activity can be solubilized from the heat-stabilized nuclear matrix prepared from HeLa S3 cells (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 12 (1994), S. 37-44 
    Details
    ISSN: 0263-6484
    Keywords: Nuclear matrix ; DNA polymerase α ; soluble complexes ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Most of the DNA polymerase α activity, bound to the heat-stabilized nuclear matrix prepared from HeLa S3 cells, was released as a matrix extract by sonication. When the extract was centrifuged in a 5-20 per cent linear sucrose gradient no definite peaks of activity could be identified. Most of the activity sedimented to the bottom of the tube under all the conditions tested, whilst the remaining activity was associated with matrix fragments of various and irregular size. No 10 S complexes, containing polymerase activity, were seen after incubation of the extract for 16 h before centrifugation. Other solubilization procedures (i.e. treatment of the matrix with chelating agents, high pH associated with reducing agents, ionic and nonionic detergents) failed to produce release of matrix-bound DNA polymerase α activity. In contrast, we released 10 S complexes, containing polymerase activity, from the matrix prepared from nuclei not exposed to heat. We conclude that a 37°C incubation of isolated nuclei before extraction with 2 M NaCl and DNase I digestion causes DNA polymerase α to bind to the nuclear matrix in a form that cannot subsequently be released as discrete components, at variance with previous results obtained with the matrix prepared from regenerating rat liver.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cbf.290120106
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  • 5
    Electronic Resource
    Electronic Resource
    Catalytic properties of DNA polymerase α activity associated with the heat-stabilized nuclear matrix prepared from HeLa S3 cells (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 12 (1994), S. 129-135 
    Details
    ISSN: 0263-6484
    Keywords: Nuclear matrix ; DNA polymerase α ; processivity ; activity ; heat stabilization ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have investigated whether or not ATP or other nucleoside di- and trisphosphates (including some nonhydrolysable ATP analogues) can stimulate the activity and/or the processivity of DNA polymerase α associated with the nuclear matrix obtained from HeLa S3 cell nuclei that had been stabilized at 37°C prior to subfractionation, as has been reported previously for DNA polymerase α bound to the nuclear matrix prepared from 22-h regenerating rat liver. We have found that HeLa cell matrix-associated DNA polymerase α activity could not be stimulated at all by ATP or other nucleotides, a behaviour which was shared also by DNA polymerase α activity that solubilizes from cells during the isolation of nuclei and that is thought to be a form of the enzyme not actively engaged in DNA replication. Moreover, the processivity of matrix-bound DNA polymerase α activity was low (〈 10 nucleotides). These results were obtained with the matrix prepared with either 2M NaCl or 0·25 M (NH4)2SO4 and led us to consider that a 37° incubation of isolated nuclei renders resistant to high-salt extraction a form of DNA polymerase α which is unlikely to be involved in DNA replication in vivo.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cbf.290120208
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesis of N,N′-Disubstituted (1R,2R)-1,2-Diaminocyclohex-4-enes by a Ruthenium-Catalyzed Ring-Closing Metathesis Reaction (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 1523-1526 
    Details
    ISSN: 1434-193X
    Keywords: Ruthenium ; Ring-closing metathesis ; Metathesis ; EPC synthesis ; 1,2-Diaminocyclohex-4-ene ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantiopure (1R,2R)-1,2-diaminocyclohex-4-ene derivatives have been synthesized by the ruthenium-catalyzed ring-closing metathesis reaction of (4R,5R)-N,N′-bis[(S)-1-phenylethyl]-4,5-diamino-1,7-octadiene dihydrochloride.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Analytical response of single polychlorinated biphenyls analysed by selected ion monitoring (1981)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 8 (1981), S. 347-350 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analytical response of 45 single polychlorinated biphenyls to electron impact mass spectrometry was measured by monitoring their positive molecular ion intensity. The results showed little variability in response within the isomer groups with the same number of chlorine atoms, and the average response is proposed as a basis for quantitation of the polychlorinated biphenyl level for the corresponding degree of chlorination. The possibility of distinguishing the level of each polychlorinated biphenyl group by a method as specific and sensitive as gas chromatography combined with mass spectrometry could be very useful, especially in toxicology studies. Preliminary data obtained from application of the technique in studies of marine organisms are presented.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200080806
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  • 8
    Electronic Resource
    Electronic Resource
    Kinetik der Umsetzung substituierter Anthracene mit MaleinsäureanhydridHerrn Prof. Dr. R. Huisgen in herzlicher Verbundenheit zum 60. Geburtstag gewidmet. (1980)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 954-970 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Kinetic Study of Reactions of Substituted Anthracenes with Maleic AnhydrideHerrn Prof. Dr. R. Huisgen in herzlicher Verbundenheit zum 60. Geburtstag gewidmet.Kinetic data for the Diels-Alder addition of 2-, 9- and 9,10-disubstituted anthracenes with maleic anhydride are interpreted in terms of FMO-theory. While the simplest form of FMO-theory does not give satisfactory results, inclusion of eigenvector coefficients at the reacting centers does provide an improvement.
    Notes: Die kinetischen Daten der Diels-Alder-Reaktion von 2-, 9- und 9,10-substituierten Anthracenen mit Maleinsäureanhydrid lassen sich durch die FMO-Theorie in ihrer einfachsten Form nur unbefriedigend beschreiben. Eine Berücksichtigung der Eigenvektorkoeffizienten der reagierenden Zentren bringt eine deutliche Verbesserung der Korrelation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198019800615
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  • 9
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    Helium–strontium isotope constraints on mantle evolution beneath the Roman Comagmatic Province, Italy (2005)
    Elsevier
    Details
    Publication Date: 2020-12-03
    Description: A study of the He isotopic ratios of fluid inclusions in olivine and pyroxene from the Roman Comagmatic Province (RCP),Italy, is presented together with 87Sr/86Sr isotope compositions of the whole rock or pyroxene phenocrysts. A clear covariation in He and Sr isotopes is apparent, with a strong northward increase in radiogenic He and Sr being evident. He and Sr isotopes ratios range from 3He/4He = 5.2 Ra and 87Sr/86Sr = 0.7056 in south Campania, to 3He/4He = 0.44 Ra and 87Sr/86Sr = 0.715905 in the northernmost Latium. Helium isotope ratios are significantly lower than MORB values and are among the lowest yet measured in subduction zone volcanism. The 3He/4He of olivine and pyroxene phenocryst-hosted volatiles appear to be little influenced by posteruptive processes and magma–crust interaction. The 3He/4He–87Sr/86Sr covariation is consistent with binary mixing between an asthenospheric mantle similar to HIMU ocean island basalts, and an enriched (radiogenic) mantle end member generated from subduction of the Ionian/Adriatic plate. The contribution of radiogenic He from metasomatic fluids and postmetasomatism radiogenic ingrowth in the wedge is strongly dependent on the initial He concentration of the mantle. Only when asthenosphere He concentrations are substantially lower than the MORB source mantle, and metasomatism occurred at the beginning of the subduction (f30 Ma), can ingrowth in the mantle wedge account for the 3He/4He of the most radiogenic basalts.
    Description: - European Social Fund - Scottish Universities - Carnegie Trust for the Universities of Scotland.
    Description: Published
    Description: 295–308
    Description: partially_open
    Keywords: Roman Comagmatic Province ; fluid inclusions ; helium ; strontium ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 516427 bytes
    Format: 539 bytes
    Format: application/pdf
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  • 10
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    A new view of the He–Ar–CO2 degassing at mid-ocean ridges: Homogeneous composition of magmas from the upper mantle (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Deep-sea exploration is rapidly improving our understanding of volatiles geochemistry in mid-ocean-ridge igneous products. It is also placing greater constraints on degassing processes of the Earth’s mantle, with the result that degassing models based on vapour–melt equilibrium are no longer able to explain the increasing number of data. In fact, such models force to postulate an upper mantle strongly heterogeneous at any scale, and cannot account for the widespread carbon supersaturation of the recovered igneous products. Here we review the global He–Ar–CO2 dataset of fluid inclusions in mid-ocean-ridge glasses using the framework of advanced modelling of multicomponent bubble growth in magmas. We display that non-equilibrium fractionations among He, Ar and CO2, driven by their different diffusivities in silicate melts, are common in most of the natural conditions of magma decompression and their signature strongly depends on pressure of degassing. Due to the comparable Ar and CO2 diffusivity, magma degassing at low pressure fractionates both the He/Ar and He/CO2 ratio by a similar extent, while the slower CO2 diffusion at high pressure causes early kinetic effects on Ar/CO2 ratio and dramatically changes the degassing path. On this ground, the very different geochemical signatures among suites of data coming from different ridge segments mainly depend on the depth of the magma chamber where the melt was stored. Besides, the variations inside a single suite highlight variable ascent speed and cooling rate of the emplaced lava. The large variations in both the He/CO2 and Ar/CO2 ratios at almost constant He/Ar, displayed in glasses coming from the Mid-Atlantic Ridge 24–30 N segment and the Rodriguez Triple Junction, are therefore interpreted as a high-pressure signature. In contrast, the simultaneous increase in both He/CO2 and He/Ar of the East Pacific Rise, Pito Seamount and South-East Indian Ridge data sets suggests the dominance of low-pressure fractionation, implying that the shallow magma chambers are at a lower depth than those of the Mid- Atlantic Ridge 24–30 N and Rodriguez Triple Junction. Our conclusions support the presence of a relationship between spreading rate and depth of high-temperature zones below ridges, and are consistent with the depth of magma chambers as suggested from seismic studies. Non-equilibrium degassing explains the volatile systematics of mid-ocean-ridge basalts by starting from a single mantle-derived magma, dispensing with the supposed need for heterogeneities in abundance ratios of volatiles in the mantle below oceanic ridges.
    Description: Published
    Description: 1747–1763
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: nonequilibrium degassing ; MORB mantle ; geochemical modeling ; fluid inclusions ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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