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  • 1
    ISSN: 0731-7085
    Keywords: 2-(α-Thenoylthio)-propionylglycine (TTPG) ; metabolism. ; oral dose proportionality ; pharmacokinetics ; propionylglycine (tiopronin) ; thiophenecarboxylic acid (TCA)
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1041
    Keywords: acetyl-L-carnitine ; renal clearance ; pharmacokinetics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of acetyl-L-carnitine hydrochloride were investigated in 6 healthy volunteers of both sexes after i.v. injection of 500 mg of the drug, expressed as inner salt. Plasma concentrations and urinary excretion of acetyl-L-carnitine (A), L-carnitine (B) and total acid soluble L-carnitine fraction were evaluated over a period lasting from 24 h before to 48 h after the administration. Plasma concentrations of A increased quickly after administration and then declined reaching base values within 12 h. Conversely, plasma concentrations of B rose more slowly, reaching a peak in 30–60 min, and then declined to base values within 24 h. Most of the injected dose of acetyl-L-carnitine was recovered in the urine during the first 24 h after administration as B and A. Mean renal clearance of both A and B during the first 12 h after injection was higher than the base values, suggesting the presence of a saturable tubular reabsorption process which may counterbalance major changes occurring in plasma concentrations of L-carnitine pattern.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 38 (1990), S. 309-312 
    ISSN: 1432-1041
    Keywords: Acetyl-L-carnitine ; renal impairment ; pharmacokinetics ; adverse reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Acetyl-L-carnitine 1.5 g and 3.0 g was administered as three divided doses on each of two occasions to 24 people with varying renal failure (creatinine clearance 127 – 8 ml·min−1). Plasma and urinary concentrations of total-L-carnitine, free (non-esterified) carnitine, short-chain esters and acetyl-L-carnitine were measured. The baseline (pre-study) concentrations of all four substances were related to renal function. Patients whose creatinine clearance was below about 30–40 ml·min−1 were had the highest concentrations. Renal elimination of all four substances was related to dose and to renal function. There was evidence for dose-related elimination, with greater elimination of the larger dose.
    Type of Medium: Electronic Resource
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  • 4
    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
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  • 5
    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
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  • 6
    Publication Date: 2017-04-04
    Description: Despite its impact in understanding oceanic crust formation and eruptive styles of related volcanism, magma dynamics at midocean ridges are poorly known. Here, we propose a new method to assess ascent rates of mid-ocean ridge basalt (MORB) magmas,as well as their pre- and sin-eruptive dynamics. It is based on the idea that a rising magma can reach a variable degree of both CO2 supersaturation in melt and kinetic fractionation among noble gases in vesicles in relation to its ascent rate through the crust. To quantify the relationship, we have used a model of multicomponent bubble growth in MORB melts, developed by extending the single-component model of Proussevitch and Sahagian [A.A. Proussevitch, D.L. Sahagian, Dynamics and energetics of bubble growth in magmas: analytical formulation and numerical modeling, J. Geophys. Res. 103 (1998), 18223–18251.] to CO2–He–Ar gas mixtures. After proper parameterization, we have applied it to published suites of data having the required features (glasses from Pito Seamount and mid-Atlantic ridges). Our results highlight that the investigated MORB magmas display very different ranges of ascent rates: slow rises of popping rock forming-magmas that cross the crust (0.01–0.5 m/s), slightly faster rates of energetic effusions (0.1–1 m/s), up to rates of 1–10 m/s which fall on the edge between lava effusion and Hawaiian activity. Inside a single plumbing system, very dissimilar magma dynamics highlight the large differences in compressive stress of the oceanic crust on a small scale. Constraints on how the systems of ridges work, as well as the characteristics of the magmatic source, can also be obtained. Our model shows how measurements of both the dissolved gas concentration in melt and the volatile composition of vesicles in the same sample are crucial in recognizing the kinetic effects and definitively assessing magma dynamics. An effort should be made to correctly set the studied samples in the sequence of volcanic submarine deposits where they are collected. Enhanced knowledge of a number of physical properties of gas-bearing MOR magmas is also required, mainly noble gas diffusivities, to describe multicomponent bubble growth at a higher confidence level.
    Description: Published
    Description: 138-158
    Description: partially_open
    Keywords: Bubble growth ; MORB ; Noble gas ; Kinetic fractionation ; Modeling ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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    Format: 695380 bytes
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  • 7
    Publication Date: 2017-04-04
    Description: We analyzed major and trace elements, Sr and Nd isotopes in ultramafic xenoliths in Miocenic age Hyblean diatremes, along with noble gases of CO2-rich fluid inclusions hosted in the same products. The xenoliths consist of peridotites and pyroxenites, which are considered to be derived from the upper mantle. Although the mineral assemblage of peridotites and their whole-rock abundance of major elements (e.g., Al2O3 = 0.8–1.5 wt.%, TiO2 = 0.03–0.08 wt.%) suggest a residual character of the mantle, a moderate enrichment in some incompatible elements (e.g., LaN/YbN = 9–14) highlights the presence of cryptic metasomatic events. In this context a deep silicate liquid is considered the metasomatizing agent, which is consistent with the occurrence of pyroxenites as veins in peridotites. Both the Zr/Nb and 143Nd/144Nd ratios of the investigated samples reveal two distinct compositional groups: (1) peridotites with Zr/Nb ≈ 4 and 143Nd/144Nd ≈ 0.5129, and (2) pyroxenites with Zr/Nb ≈ 20 and 143Nd/144Nd ≈ 0.5130. The results of noble-gas analyses also highlight the difference between the peridotite and pyroxenite domains. Indeed, the 3He/4He and 4He/40Ar* ratios measured in the fluid inclusions of peridotites (respectively 7.0–7.4 ± 0.1 Ra and 0.5–8.2, where Ra is the atmospheric 3He/4He ratio of 1.38 × 10− 6) were on average lower than those for the pyroxenites (respectively 7.2–7.6 Ra and 0.62–15). This mantle heterogeneity is interpreted as resulting from a mixing between two end-members: (1) a peridotitic layer with 3He/4He ≈ 7 Ra and 4He/40Ar* ≈ 0.4, which is lower than the typical mantle ratio (~ 1–4) probably due to melt extraction events, and (2) metasomatizing mafic silicate melts that gave rise to pyroxenites characterized by 3He/4He ≈ 7.6 Ra, with a variable 4He/40Ar* due to degassing processes connected with the ascent of magma at different levels in the peridotite wall rock. The complete geochemical data set also suggests two distinct mantle sources for the xenolithic groups highlighted above: (1) a HIMU (high-μ)-type source for the peridotites and (2) a DM (depleted mantle)-type source for the pyroxenites.
    Description: Published
    Description: 70-81
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: restricted
    Keywords: noble gases ; mantle ; xenoliths ; fluid inclusions ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
    Publication Date: 2017-04-04
    Description: We investigated the carbon isotope composition of mantle source beneath the Hyblean Plateau (southeast Sicily, Italy) by studying CO2 in fluid inclusions from ultramafic xenoliths recovered in some Miocene diatremes. In order to constrain the processes influencing the isotopic marker of carbon we combined d13CCO2 results with information about noble gases (He and Ar) obtained in a previous investigation of the same products. Although Ar/CO2 and He/Ar ratios provide evidence of Rayleigh-type fractional degassing, the isotopic geochemistry of carbon is poorly influenced by this process. Mixing related to metasomatic processes where MORB-type pyroxenitic melts permeate a peridotite mantle probably contaminated by crustal fluids inherited from a fossil subduction can explain the measured d13C and CO2/3He variations, ranging from 24&to 22& and from 109 to 1010, respectively. Simple mass-balance calculations highlighted that the Hyblean peridotite source was mainly contaminated by the carbonate source, being carbonate and organic matter present at a ratio that varied within the range from 7:1 to 4:1.
    Description: Published
    Description: 600-611
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: xenoliths ; mantle heterogeneity ; Hyblean Plateau ; fluid inclusions ; isotopic carbon ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publication Date: 2017-04-04
    Description: We have analyzed by single-step crushing helium and argon isotopes in olivine and orthopyroxene from mantle xenoliths of Calatrava (CLV) in central Spain and Tallante (TL) in southeast Spain. The investigation focused on carefully selected samples previously characterized in terms of major and trace elements on both bulk rock and constituent minerals, and Sr and Nd isotopes on clinopyroxene separates. Six analyses were performed on protogranular spinel lherzolites from CLV, and 17 were performed on spinel harzburgites, lherzolites, and orthopyroxenites from TL. The 40Ar/36Ar ratio was between 296 and 622, indicating atmospheric contamination, which probably occurred during exposure to the surface. The helium-isotope ratio (3He/4He) ranged between 3.6 and 6.5 Ra in CLV samples and between 1.4 and 5.7 Ra in TL samples. There was a positive correlation between the 3He/4He and 4He/40Ar* ratios, possibly reflecting diffusive fractionation between 3He, 4He, and 40Ar within mantle sections interacting with ascending melts. However, the difference between the maximum 3He/4He ratios measured in CLV and TL appears to be related to significant differences in the metasomatic melts that affected the two sectors of the lithospheric mantle. In agreement with the findings of previous studies, the helium isotopes at CLV are compatible with metasomatism due to ascending HIMU-type asthenospheric melts. In contrast, the lower 3He/4He values recorded at TL suggest subduction-related metasomatic components that are possibly related to the Cenozoic subduction of the Betic system. Such event plausibly introduced crust-derived fluids that metasomatized the mantle wedge, slightly decreasing its 3He/4He value. Noble gases appear decoupled from other elements during these mantle processes, since comparatively low 3He/4He values have been recorded also in samples that are relatively unmetasomatized in terms of incompatible lithophile elements. We hypothesize a role for volatile-dominated, CO2-rich fluids progressively decoupling from the ascending metasomatic melts and migrating in the surrounding peridotite matrix to form a diffuse aureola enriched in noble gases.
    Description: Published
    Description: 18-26
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: noble gas ; xenoliths ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 10
    Publication Date: 2017-04-04
    Description: We present the first chlorine isotope compositional data for gases and lavas from Mount Etna (Italy), and to our knowledge, of active Mediterranean volcanism. We investigated lavas erupted and gases discharged during 2008-2011 from a high-temperature fumarole (HT; 〉300°C) and plume gases from both North East and Central Craters. Most of the samples vary in a narrow range of chlorine isotope composition (37Cl values ≈ 0 ± 0.7‰) with gases partially overlapping with rocks. Only HT gases sampled in 2009 have been clearly affected by secondary processes (37Cl values 〉 15.9‰), resulting in partial removal of chlorine and isotopic fractionation producing a 37Cl enrichment in the residual gaseous HCl. These secondary processes also affect, although to a lesser extent, plume gases from North East Crater (NEC). Although post-magmatic processes are able to modify the chlorine isotope composition, 37Cl values are not affected by magma degassing for residual fractions ≥ 0.3 in the melt, or any effect is within our data variability. Finally, 37Cl values and Cl/K ratios of magmatic chlorine constrain the Etnean source to be compatible with depleted mantle (DMM) contaminated by altered oceanic crust (AOC), in agreement with indications from more common isotopic tracers of mantle processes.
    Description: Published
    Description: 134-142
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: Mount Etna ; chlorine isotope ; plume ; fumarole ; degassing ; mantle source ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 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
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