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Berlin Brandenburg

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  • 1
    Language: English
    In: Journal of Plant Nutrition and Soil Science, December 2018, Vol.181(6), pp.894-904
    Description: Sonication is widely used for disruption of suspended soil aggregates. Calorimetric calibration allows for determining sonication power and applied energy as a measure for aggregate disrupting forces. Yet other properties of sonication devices (., oscillation frequency and amplitude, sonotrode diameter) as well as procedure details (soil‐to‐water ratio, size, shape, and volume of used containers) may influence the extent of aggregate disruption in addition to the applied energy. In this study, we tested potential bias in aggregate disruption when different devices or procedures are used in laboratory routines. In nine laboratories, three reference soil samples were sonicated at 30 J mL and 400 J mL. Aggregate disruption was estimated based on particle size distribution before and after sonication. Size distribution was obtained by standardized submerged sieving for particle size classes 2000–200 and 200–63 µm, and by dynamic imaging for particles 45 W). Thus, these sonication device properties need to be listed when reporting on sonication‐based soil aggregate disruption. The overall small differences in the degree of disruption of soil aggregates between different laboratories demonstrate that sonication with the energies tested (30 and 400 J mL) provides replicable results despite the variations regarding procedures and equipment.
    Keywords: Disaggregation ; Particle Size Fractions ; Reproducibility ; Round‐Robin Test ; Ultrasound
    ISSN: 1436-8730
    E-ISSN: 1522-2624
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  • 2
    In: European Journal of Soil Science, May 2019, Vol.70(3), pp.454-465
    Description: Soil structural traits provide links between soil structure and ecosystem functioning. The size and stability of soil aggregates are assumed to provide information on aggregate formation and turnover. A standard method to analyse these traits is to determine the mass distribution on sieves. The major drawback of this method is the small size resolution because of a small number of size classes. A promising, yet still unexplored, method for size distribution analysis in soil science, is dynamic image analysis, which foremost allows a much larger diameter resolution and the assessment of both size and shape distributions. The aim of our study was to validate the applicability of dynamic digital image analysis in combination with sonication to characterize the size and shape distribution and the stability of aggregates. We used two different heterogeneous reference materials and three different soil samples with different aggregate stabilities to test this method. The soil samples were chosen based on increasing clay, humus and calcium carbonate contents. The method yielded reproducible results for diameter and shape distributions for both reference materials and soil samples. The most important improvement compared to well‐established methods was the extremely large size resolution. This allows specification of the pattern of diameter‐dependent breakup curves by relating them to specific soil properties. The information on sphericity adds supplementary information on the aggregates released. We found much lower sphericity of 1‐mm aggregates mobilized from topsoil samples formed from the activity of living organisms than aggregates mobilized from subsoil samples formed mainly by physicochemical processes. Highlights Our aim was to validate dynamic digital image analysis to characterize soil aggregates.Dynamic image analysis allows high resolution and shape analysis compared to established methods.The method yielded reproducible results for diameter and shape distributions.We established high‐resolution disruption patterns of aggregates enabling new approaches in future research.
    Keywords: Aggregate Breakdown Dynamics ; Particle‐Size Distribution ; Ultrasonic Dispersion
    ISSN: 1351-0754
    E-ISSN: 1365-2389
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  • 3
    Language: English
    In: Journal of Biological Inorganic Chemistry, 2015, Vol.20(5), pp.841-853
    Description: The structure-activity relationships of chiral 1,2-diaminophenylalkane platinum(II) anticancer derivatives are studied, including interactions with telomeric- and genomic-like DNA sequences, the pKa of their diaqua species, structural properties obtained...
    Keywords: Natural Sciences ; Biological Sciences ; Biochemistry And Molecular Biology ; Naturvetenskap ; Biologiska Vetenskaper ; Biokemi Och Molekylärbiologi ; Cancer ; Platinum ; G-Quadruplex ; Conceptual Dft ; Rxes
    ISSN: 0949-8257
    E-ISSN: 14321327
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  • 4
    Language: English
    In: Journal of Ornithology, 2016, Vol.157(1), pp.333-342
    Description: Maintaining or restoring old-growth stand structures in mountain forests, including deadwood and snags provided by natural disturbances, is considered critical for the conservation of secondary cavity-nesting birds. Under current climate warming, old-growth mountain forests might become increasingly important for boreo-alpine species living in the southern part of their ranges. Here, we focused on hierarchical habitat selection by Eurasian Pygmy Owls Glaucidium passerinum in mixed mountain forests at their low latitude range limit in the southern French Prealps. We quantified Pygmy Owl habitat use at complementary hierarchical levels, from the local population to individual home ranges, by combining systematic playback counts and radio-telemetry. Mean home range sizes for breeding adult males covered 0.67 km 2 , ranging between 0.46 and 0.98 km 2 . We found evidence for Pygmy Owl habitat selection being a consistently hierarchical process, with (1) fir-dominated forests selected as the main habitat at the population level; (2) old-growth fir-dominated forest stands including edges with grassland gaps and karstic eroded areas selected at the home range level; and (3) amount of surrounding dead or decaying spruces increasing the occurrence probability of owl nesting cavities. Conserving Pygmy Owls at their low latitude range limit therefore requires the maintenance of old-growth mixed forests dominated by firs that provide these critical habitat features within a complex and heterogeneous landscape mosaic. Hierarchische Habitat-Auswahl beim Sperlingskauz ( Glaucidium passerinum ) in alten Waldbeständen des französischen Voralpenlandes Das Erhalten oder die Wiederherstellung alter Bestandsstrukturen in Gebirgswäldern inklusive des durch natürliche Störeinflüsse entstandenen Totholzes und der Baumstümpfe wird als ausschlaggebend für den Erhalt derjenigen Vögel betrachtet, die in sekundären Bruthöhlen nisten. Bei der derzeitigen Klimaerwärmung könnten die alten Gebirgswald-Bestände für diejenigen boreoalpinen Arten immer wichtiger werden, die am südlichen Rand ihrer Verbreitungsgebiete leben. In unserer Studie konzentrierten wir uns auf die hierarchische Habitat-Auswahl von Sperlingskäuzen ( Glaucidium passerinum ) in Mischwäldern auf mittlerer Höhe der südlichen französischen Voralpen. Mit einer Kombination von Radio-Telemetriedaten und systematisch erfassten Ruf-Zählungen quantifizierten wir die Nutzung der Habitate auf allen Ebenen: von der örtlichen Population bis hin zu den alltäglichen Lebensräumen der Einzeltiere. Die Größe der individuellen Lebensräume brütender, adulter Männchen reichte von 0,46 bis 0,98 km2 und betrug im Schnitt 0,67 km2. Wir fanden Hinweise darauf, dass die Habitat-Auswahl bei Sperlingskäuzen ein durchgängig hierarchischer Vorgang ist: (i) Tannen-dominierte Wälder wurden auf Populations-Ebene als wichtigste Habitate ausgewählt, (ii) auf der Ebene der individuellen Habitate lagen Altbestände von Tannenwäldern, die mit Wiesenflecken und karstig erodierten Bereichen durchsetzt war, an erster Stelle, und (iii) die Menge an toten oder vermodernden Fichten erhöhten die Wahrscheinlichkeit, Nisthöhlen der Sperlingskäuze zu finden. Sperlingskäuze auf den niedrigeren Höhen ihrer Verbreitungsgebieten zu halten, erfordert daher den Erhalt von alten, vorherrschend mit Tannen besetzten Mischwäldern, die innerhalb eines komplexen und heterogenen Landschaftsbildes diese wichtigen Auswahlkriterien für Habitate bieten.
    Keywords: Boreal owl ; Home range ; Mountain forests ; Radio-telemetry ; Secondary cavity-nester ; Southern distribution limit
    ISSN: 2193-7192
    E-ISSN: 2193-7206
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  • 5
    In: Analyst, 2016, Vol.141(4), pp.1226-1232
    Description: Platinum-based drugs are commonly used in cancer treatment. The biological activity of a metallodrug is obviously closely related to its chemical and stereochemical characteristics. An overlooked aspect is the effect of the ligand to the electronic structure of the metal atom (coordinated atom). We report herein a Resonant X-ray Emission Spectroscopy (RXES) study on the chemical speciation of chiral platinum complexes in which diastereomers are distinguished on the basis of their metal electronic configuration. This demonstrates RXES high chemical speciation capabilities, a necessary property to further investigate the reactivity of the Pt atom towards nucleophiles or bionucleophiles, and an important complement the previously reported RXES abilities, namely that it can be employed for in situ studies at physiological concentrations.
    Keywords: Spectrometry, X-Ray Emission ; Antineoplastic Agents -- Chemistry ; Organoplatinum Compounds -- Chemistry;
    ISSN: 0003-2654
    E-ISSN: 1364-5528
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  • 6
    Language: English
    In: JBIC Journal of Biological Inorganic Chemistry, 2015, Vol.20(5), p.841(13)
    Description: Byline: Gilles Berger (1), Luca Fusaro (2), Michel Luhmer (2), Joanna Czapla-Masztafiak (3), Ewelina Lipiec (3), Jakub Szlachetko (4,5), Yves Kayser (4), Daniel L. A. Fernandes (6), Jacinto Sa (6,7), Francois Dufrasne (1), Sophie Bombard (8) Keywords: Cancer; Platinum; G-quadruplex; Conceptual DFT; RXES Abstract: The structure--activity relationships of chiral 1,2-diaminophenylalkane platinum(II) anticancer derivatives are studied, including interactions with telomeric- and genomic-like DNA sequences, the pKa of their diaqua species, structural properties obtained from DFT calculations and resonant X-ray emission spectroscopy. The binding modes of the compounds to telomeric sequences were elucidated, showing no major differences with conventional cis-platinum(II) complexes like cisplatin, supporting that the cis-square planar geometry governs the binding of small Pt(II) complexes to G4 structures. Double-stranded DNA platination kinetics and acid--base constants of the diaqua species of the compounds were measured and compared, highlighting a strong steric dependence of the DNA-binding kinetics, but independent to stereoisomerism. Structural features of the compounds are discussed on the basis of dispersion-corrected DFT, showing that the most active series presents conformers for which the platinum atom is well devoid of steric hindrance. If reactivity indices derived from conceptual DFT do not show evidences for different reactivity between the compounds, RXES experiments provide new insight into the availability of platinum orbitals for binding to nucleophiles. Author Affiliation: (1) Laboratoire de Chimie Pharmaceutique Organique, Universite Libre de Bruxelles, Campus Plaine CP205/5, Bd du Triomphe, 1050, Brussels, Belgium (2) Laboratoire de Resonance Magnetique Nucleaire Haute Resolution, Universite Libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50, CP160/08, 1050, Brussels, Belgium (3) The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland (4) Paul Scherrer Institute (PSI), Villigen, Switzerland (5) Institute of Physics, Jan Kochanowski University in Kielce, Kielce, Poland (6) Angstrom Laboratory, Department of Chemistry, Uppsala University, Uppsala, Sweden (7) Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland (8) Homeostasie Cellulaire et Cancer, UMR-S INSERM 1007, Universite Paris Descartes, 45 rue des Saint-Peres, 75006, Paris, France Article History: Registration Date: 07/05/2015 Received Date: 02/04/2015 Accepted Date: 03/05/2015 Online Date: 16/05/2015 Article note: Electronic supplementary material The online version of this article (doi: 10.1007/s00775-015-1270-6) contains supplementary material, which is available to authorized users.
    Keywords: Nuclear Physics ; Cancer Treatment ; Stereoisomers
    ISSN: 0949-8257
    Source: Cengage Learning, Inc.
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  • 7
    Language: English
    In: Drug Discovery Today: Technologies, September 2015, Vol.16, pp.1-6
    Description: This review presents a new application of Resonant X-ray Emission Spectroscopy (RXES) to study the mechanism of action of metal containing anticancer derivatives and in particular platinum and . The technique is an example of a photon-in photon-out X-ray spectroscopic approach, which enables chemical speciation of drugs to be determined and therefore to derive action mechanisms, and to determine drug binding rates under physiological conditions and therapeutic concentrations. This is made feasible due to the atomic specificity and high penetration depth of RXES. The review presents examples of the three main types of information that can be obtained by RXES and establishes an experimental protocol to perfect the measurements within cells.
    Keywords: Pharmacy, Therapeutics, & Pharmacology
    ISSN: 1740-6749
    E-ISSN: 1740-6749
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  • 8
    Language: English
    In: Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry, July 2015, Vol.20(5), pp.841-53
    Description: The structure-activity relationships of chiral 1,2-diaminophenylalkane platinum(II) anticancer derivatives are studied, including interactions with telomeric- and genomic-like DNA sequences, the pKa of their diaqua species, structural properties obtained from DFT calculations and resonant X-ray emission spectroscopy. The binding modes of the compounds to telomeric sequences were elucidated, showing no major differences with conventional cis-platinum(II) complexes like cisplatin, supporting that the cis-square planar geometry governs the binding of small Pt(II) complexes to G4 structures. Double-stranded DNA platination kinetics and acid-base constants of the diaqua species of the compounds were measured and compared, highlighting a strong steric dependence of the DNA-binding kinetics, but independent to stereoisomerism. Structural features of the compounds are discussed on the basis of dispersion-corrected DFT, showing that the most active series presents conformers for which the platinum atom is well devoid of steric hindrance. If reactivity indices derived from conceptual DFT do not show evidences for different reactivity between the compounds, RXES experiments provide new insight into the availability of platinum orbitals for binding to nucleophiles.
    Keywords: Antineoplastic Agents -- Chemistry ; DNA, Neoplasm -- Drug Effects ; Hydrocarbons, Chlorinated -- Pharmacology ; Organoplatinum Compounds -- Chemistry
    ISSN: 09498257
    E-ISSN: 1432-1327
    Source: MEDLINE/PubMed (U.S. National Library of Medicine)
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  • 9
    Language: English
    In: European Journal of Pharmacology, 1986, Vol.130(3), pp.203-208
    Description: The antinociceptive effects obtained in arthritic rats with morphine, the opioid mu-agonist DAGO [D-Ala2,MePhe4,Gly-ol5]enkephalin, the delta-selective agonist DTLET [D-Thr2, Leu5]enkephalyl-Thr, and the kappa-agonist U-50,488H were compared to their corresponding effects in normal animals and morphine-pretreated arthritic rats, respectively, using a paw pressure test. The effects of the mu- and kappa-agonists were increased in arthritic rats. While morphine-treated rats were cross-tolerant to the mu- and kappa-agonists, no tolerance to the delta-selective agonist was found. The possibility that the potent action of morphine in this model for chronic inflammatory pain is mediated partly through kappa-mechanisms is discussed.
    Keywords: Arthritic Rats ; Opioid Receptors ; Analgesia ; Tolerance ; Pharmacy, Therapeutics, & Pharmacology
    ISSN: 0014-2999
    E-ISSN: 1879-0712
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  • 10
    Language: English
    In: Physical review letters, 08 December 2017, Vol.119(23), pp.231101
    Description: According to the weak equivalence principle, all bodies should fall at the same rate in a gravitational field. The MICROSCOPE satellite, launched in April 2016, aims to test its validity at the 10^{-15} precision level, by measuring the force required to maintain two test masses (of titanium and platinum alloys) exactly in the same orbit. A nonvanishing result would correspond to a violation of the equivalence principle, or to the discovery of a new long-range force. Analysis of the first data gives δ(Ti,Pt)=[-1±9(stat)±9(syst)]×10^{-15} (1σ statistical uncertainty) for the titanium-platinum Eötvös parameter characterizing the relative difference in their free-fall accelerations.
    Keywords: Astrophysics - Instrumentation And Methods For Astrophysics ; Astrophysics - Cosmology And Nongalactic Astrophysics ; General Relativity And Quantum Cosmology;
    ISSN: 00319007
    E-ISSN: 1079-7114
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